design and analysis of foldable human-powered vehicle · design and analysis of foldable...

Proceedings of Mechanical Engineering Research Day 2017, pp. 128-129, May 2017

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© Centre for Advanced Research on Energy

Design and analysis of foldable human-powered vehicle Mohd Azman Abdullah1,2,*, Mohamad Alif Fayumi Ahmad1, Shafizal Mat1,2, Faiz Redza Ramli1,2

1) Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka,

Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka,

Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia

*Corresponding e-mail: [email protected]

Keywords: Human-powered vehicle; foldable mechanism; transformable chassis

ABSTRACT – It is common for 2-wheel human-

powered vehicle (HPV) available in foldable

mechanism i.e. foldable bicycle. However, for 3-wheel

HPV, the foldable mechanism is quite difficult to be

designed. In this paper, a 3-wheel recumbent type

foldable HPV is designed and analyzed. The objective

of this research is to reduce the envelop volume and

areas of the HPV for storage and easy transportation.

Using simple mechanism, the foldable HPV is

successfully designed and analyzed with reduction of 50

% in envelope volume of its original condition.

1. INTRODUCTION

Human powered vehicle (HPV) is an

environmentally friendly and affordable vehicle that can

help people to achieve the green technology concept.

HPV is a one type of vehicle that powered only by

muscular strength to move on the road [1]. It is a land

vehicle with seat position that is inclined backwards.

The current HPV design is not foldable and may be

difficult to be carried around and stored for future use.

This HPV is redesigned for foldable capability by using

fasteners at the joint. The new design makes the HPV

compact [2].

Generally, the current HPV is not easy to be

carried to everywhere in a car rear trunk due to the

space constraint [3]. HPV may be bigger in size

compared to the bicycle. With all the problems in

current HPV, the next possible solution is the ability of

the HPV to be folded to reduce the envelope volume. If

this HPV is foldable, or detachable, it may use less

space and easy to be stored [3].

There is a part of this HPV which can be folded.

The main body of this HPV can be folded while the

wheel and other components are remaining unchanged.

The new design of the HPV also uses a compact joint

which can provide overlap condition when the main

body of the HPV is folded. Then, the seat of this HPV

also can be folded and adjusted for user comfortable

purpose.

The frame of HPV is the important part in the

system. This is because the frame or body will support

the load and vibration [4-7] and also can be folded.

There are several option in term of frame geometry. The

design space defined by the conventional, forward

facing and recumbent rider position. The proper design

and analysis is very crucial. The material used for the

frame can affect the load and dynamic stability [8] of

the HPV.

2. METHODOLOGY

The drawing for foldable HPV was designed using

a computer aided design (CAD) software CATIA. The

design concept for this foldable HPV is based on the

ergonomic, aerodynamic [9], highly engineered, and

easy to be manufactured and fulfil the safety criteria.

The original chassis design of the HPV is shown by

Figure 1. The location of the fold point is at the centre

of the chassis in order to maximise the reduction in

chassis length.

Figure 1 Original chassis design of HPV.

3. DESIGN & ANALYSIS

The assembly design for foldable HPV is shown in

Figure 2. The main objective of this project is to reduce

the space used for the HPV. After the HPV was folded

the percentage of space reduction will be calculated.

The percentage reduction for HPV before and after

foldable are calculated after all parts are completely

folded. The design for HPV before and after foldable

can be shown on the Figure 3.

4. RESULTS AND DISCUSSION

The percentage of size reduction of the foldable

HPV is calculated and summarized in Table 1. The

envelope volume of the foldable HPV is reduced 50.6

%. This is half of the original volume of the HPV. The

envelope areas for the top, side and front are also

reduced to 60.4 %, 17.3 % and 26.9 % respectively.

These have proven that the main objective of the

foldable mechanism for the HPV is achieved. The

cubical volume of the HPV is represented in Figure 4.

Abdullah et al., 2017

129

Figure 2 Foldable HPV design.

Figure 3 Foldable analysis.

Table 1 Percentage of reduction.

Fix

HPV

Foldable

HPV

%

Reduction

Volume, m3 2.32 1.15 50.6

Top area, m2 2.84 1.23 60.4

Side area, m2 1.79 1.48 17.3

Front area, m2 1.08 0.79 26.9

Figure 4 Cubical volume of foldable HPV.

5. CONCLUSION

The design and analysis of foldable HPV is

successfully performed and presented in this paper. The

drawing for foldable HPV is using the CAD software

CATIA. The envelope volume of the HPV is reduced 50

% and the envelope areas are reduced significantly. The

main objective of the paper is achieved.

6. ACKNOWLEDGEMENT

The authors gratefully acknowledged the

Advanced Vehicle Technology (AcTiVe) research group

of Centre for Advanced Research on Energy (CARe),

the financial support from Universiti Teknikal Malaysia

Melaka and The ministry of Education, Malaysia under

Short Term Research Grant, Grant no.

PJP/2014/FKM(10A)/S01330.

REFERENCES

[1] M.A. Abdullah, S.A. Shamsudin, F.R. Ramli, M.H.

Harun, M. A. Yusuff, “Design and fabrication of a

recreational human-powered vehicle”,

International Journal of Engineering Science

Invention, vol. 5, no. 2, pp. 11-14, 2016.

[2] A.V.R.K. Teja, J. Sri Harsha, N.S.K.Teja, A.Teja

and P.S Afridi Khan, “Kinematic design and

fabrication of four bar mechanism to steer a human

powered vehicle”, International Journal for

Research in Emerging Science and Technology,

vol. 3, no. 4, pp. 102-107, 2016.

[3] R.U. Urunkar and P.P. Deshpande, “Study of drive

mechanisms of bicycle, tricycle or like vehicles to

optimize operating performance - a review”,

International. Journal of Engineering Research

and Applications, vol. 4, no. 1, pp. 214–219, 2014.

[4] M.A. Abdullah, M.R. Mansur, N. Tamaldin, and K.

Thanaraj, “Development of formula varsity race

car chassis”, IOP Conference Series: Materials

Science and Engineering, vol. 50, no. 1, pp.

012001, 2013.

[5] M.A. Abdullah, M.R. Mansor, M.Mohd Tahir, S.I.

Abdul Kudus, M.Z. Hassan and M.N. Ngadiman,

“Design, analysis and fabrication of chassis frame

for utem formula varsitytm race car”, International

Journal of Mining, Metallurgy & Mechanical

Engineering, vol. 1, no. 1, pp. 75-77, 2013.

[6] M.A. Abdullah, A.H. Mohamad and F.R. Ramli,

“Design, Analysis and Fabrication of Fixed-Base

Driving Simulator Frame”, The Journal of

Engineering and Technology, vol 4, no. 2, pp. 85-

102, 2013.

[7] M.A. Abdullah, N. Tamaldin, M.A. Mohamad, R.

S. Rosdi, and M.N.I. Ramlan, “Energy harvesting

and regeneration from the vibration of suspension

system”, Applied Mechanics and Materials, vol.

699, pp. 800-805, 2015.

[8] M.A. Abdullah, M.A. Salim, M.Z. Mohammad

Nasir, M.N. Sudin, F.R. Ramli, “Dynamics

performances of Malaysian passenger vehicle”,

ARPN Journal of Engineering and Applied

Sciences, vol. 10, no. 17, pp. 7759-7763, 2015.

[9] M.N. Sudin, M.A. Abdullah, F.R. Ramli, M.T.

Musthafah, S.A. Shamsudin, “Review of research

on vehicles aerodynamic drag reduction methods”,

International Journal of Mechanical and

Mechatronics Engineering, vol. 14, no. 2, pp. 35-

47, 2014.


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Car seat design using RULA analysis S. Mat1,2,*, M.A. Abdullah1,2, A.R. Dullah1,2, S.A. Shamsudin1,2, M.F. Hussin1





Keywords: Car seat; optimised; RULA

ABSTRACT – This paper presents an ergonomics

study of car seat design using Rapid Upper Limb

Assessment (RULA) analysis. A car seat was designed

using CATIA and it is then analysed using RULA to

obtain the initial ergonomics data of the car seat. An

optimisation process is done subject to the initial data

obtained and it is then analysed using RULA analysis to

obtain the final score that is aimed to achieve action

level 1. As a result, the final design of the car seat is

optimized ergonomically based on the final score

obtained from 4 to 2 (Action level 1).

1. INTRODUCTION

Nowadays, there are so many types and designs of

car seat. The common research questions arise from the

car seat designs are such as; whether the seat is suitable

and comfortable enough for a driver to sit on, and

whether the seat meets customer’s requirements. The

design of car seat plays a big role for drivers to achieve

a better driving experience and also for their health.

Good seats should meet customer’s needs and consider

ergonomics criteria and also safety features especially

for a driver who frequently commutes from one place to

another. The seat also has to be firm and strong enough

to hold the person who sits on it.

Ergonomics is the applied science of designing and

developing equipment like a workstation layout and

work strategies that best suit and protect the human

body. The goal of ergonomics is to minimize fatigue,

discomfort, injury, and emotional stress. Derived from

the Greek words ergo (work) and nomos (natural laws),

ergonomics literally means the laws of work.

Ergonomics defined by Fernandez [1] as the design of

the workplace, equipment, machine, tool, product,

environment, and system, taking into consideration the

human’s physical, psychological, biomechanical, and

psychological capabilities, and optimising the

effectiveness and productivity of work systems while

assuring the safety, health, and well-being of the

workers. In a nutshell, ergonomics encompasses the

relationship between humans, machines systems, job

design and the work environment. By approaching work

practices (stretching, reaching, or sitting) from an

ergonomically correct point of view, a worker actually

becomes stronger, healthier and more productive. If

management does not address ergonomics discomfort, a

worker will act on a subconscious level, adapting

his/her behaviour to lighten the pain [2]. Engineering

ergonomics focuses on the fit between a person’s body

size and physical capabilities (also known as

“anthropometrics”) and design of job task and

workspace. Engineering ergonomics can provide

recommendations on how to set up a work space. While

this approach plays a significant role in determining

design and furnishings in the office, it is limited by its

exclusive focus on the physical mechanics of work [3].

Depending on what a driver needs for his or her

comfort; seats can come from a wide range of selection.

The popular types of driver seats are bucket seats, bench

seats, and racing seats. A bucket seat is a seat contoured

to hold one person, distinct from bench seats which are

flat platforms designed to seat multiple people. A bench

seat is a driver’s seat that extends to connect the front

seats, forming a long bench that runs the width of the

car. Racing seats resemble bucket seats, only with a

much deeper base and additional equipment. One way

to identify a racing seat is by the bolsters, which are

wide elements on the sides of racing seats that hold the

driver in place during sharp turns.

2. METHODOLOGY

The Rapid Upper Limb Assessment (RULA)

provides an analysis of the manikin's upper limbs based

on variables such as weight, distance and frequency.

RULA is a survey method developed for use in human

factor or ergonomic investigations of workplaces where

work related upper limb disorders are reported. RULA

is a screening tool that assesses biomechanical and

postural loading on the whole body with particular

attention to the neck, trunk and upper limbs. RULA is

intended to be used as part of a broader ergonomics

study [4].

The RULA was developed and particularly used to

evaluate the risk to workers engaged sedentary tasks

such as workers at video terminals or the risk from other

tasks in which the operators sits or the risks for

workplace in which the worker stands for a large part of

the time. The analysis input data are body posture (head,

trunk, and upper limbs), the force used, and the type of

movements or actions performed, repetitively [4].

RULA analysis is used to analyse many facets of

manikin posture based on a combination of

automatically detected variables and user data. For this

study, certain parts of manikin’s body are adjusted

according to seat design and not all parts of the body are

Mat et al., 2017

131

moved. This is because the body parts that undergo

evaluation are back spine, leg, neck and head.

Table 1 shows the RULA action level and its

description. The score is given as number scale from

lowest score 1 to the highest score 7. Each action level

has its own descriptions which explain about what are

the consequences if the analysis meets the allocated

score.

Table 1 RULA scoring and descriptions [4].

Action

Level

RULA

Score Description

1 1-2 The person is working in the best

posture with no risk of injury from

their work posture

2 3-4

The person is working in a posture

that could present some risk of

injury from their work posture,

and this score most likely is the

result of one part of the body

being in a deviated and awkward

position

3 5-6

The person is working in a poor

posture with a risk of injury from

their work posture, and the

reasons for this need to be

investigated and changed in the

near future to prevent an injury

4 7+

The person is working in the

worst posture with an immediate

risk of injury from their work

posture, and the reasons for this

need to be investigated and

changed immediately to prevent

an injury


The final concept design consists of less complex

design was selected (concept 5 from 6 concepts) using

weighted rating method as shown in Table 2. All the

curves and edges are minimal and not too complex as it

is one of the best design. The backrest and the headrest

are separated and this means the headrest can be

independently adjusted up and down according the

driver’s comfort. Furthermore, this gives better support

for the driver’s back.

Table 2 Weighted rating method.

Based on the RULA analysis, the final score value

is 4 which trunk, neck and leg are the main contributors

for this score and this means the person is working in a

posture that could present some risk of injury from their

work posture. This score most likely is the result of one

part of the body being in a deviated and awkward

position. Hence, this should be investigated and

corrected [4]. It is found that the back rest is larger than

driver’s back.

Figure 1 RULA analysis after improvement.

After improvement and optimization, the final

score has achieved 2 that is lower than the previous

design as shown in Figure 1. It indicates that posture in

this design is acceptable where the person is working in

the best posture with no risk of injury from their work

posture [4]. Regarding to redesigned process

(optimisation), the height and width of seat back is

reduced so that the manikin’s body (based on Asian

anthropometric data) is placed perfectly on the seat and

the whole body is fully supported. In addition, some

portion of the side bolsters has also been removed to

reduce its breadth.

4. CONCLUSION

The proposed design was developed using CATIA

and then it is analysed ergonomically using the RULA

analysis to obtain the final score. The initial design is

then optimised with some changes in the seat back

height and width, as well as the shrinking of the

bolsters. By using RULA analysis, the ergonomics

design of car seat is proposed with the reduction of final

score from 4 to 2. This indicates that the driver is

working in the best posture with no risk of injury from

their work posture.

REFERENCES

[1] J.E., Fernandez, “Ergonomics in the workplace,"

Facilities, vol. 13, no. 4, pp. 20-27, 1995.

[2] Z.M., Makhbul, D., Idrus, M.R., Abdul Rani,

“Ergonomics design on the work stress outcomes,”

Jurnal Kemanusiaan, vol. 9, pp. 50-61, 2007.

[3] K., Brookhuis, A., Hedge, H., Hendrick, E., Salas,

and N., Stanton, “Handbook of Human Factors and

Ergonomics Models,” Florida: CRC Press.

[4] L., McAtamney, and E.N., Corlett, “RULA: A

survey method for the investigation of work-related

upper limb disorders,” Applied Ergonomics, 24(2),

pp. 91-99, 1993.


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Automated sorting system design in manufacturing industries S. Mat1,2,*, M.A. Abdullah1,2, F.R. Ramli1,2, S.I. Abdul Kudus1,2, A.A. Abdul Aziz1





Keywords: Automated sorting; recycling; optimized

ABSTRACT – This paper presents the conceptual

design of the automated sorting system in

manufacturing industries for plastic recycling that aims

to optimize the dimensions and space requirement for

the proposed design. The design process begins by

concept generation and selection. Three conceptual

designs were produced and then one was selected by

using concept screening method. The final design was

developed so that it optimizes the space usage when

installation for low to medium size of operation and it is

also having a suitable sorting rate that required by low

to medium size recycling industries.

1. INTRODUCTION

Automated sorting system is a process to sort

mixed items, colours or sizes like plastics, boxes, letters,

and clothes automatically using selected system.

Automated sorting system in manufacturing industries is

used instead of manual sorting system because it is

more reliable, cost effective and efficient. Manual

sorting relies on plant personnel who visually identify

and pick plastic bottles as they travel along the

conveyor belt [1]. These bottles are then sorted into the

respective containers. Manual sorting may not be a

suitable option for recycling facilities of high

throughput. It has also been noted that the high turnover

among sorting line workers had caused difficulties in

achieving consistency in the plastic separation process

[2].

Automated sorting systems employ a detection

system or a combination of detection systems to identify

the different types of recyclable plastic. These detection

systems utilize state-of-the art technologies to

automatically sort plastics either by resin type, shape,

colour or both. Automated sorting system of plastics for

recycling can be the solution to sort the plastics for

recycles in a lot of amount. The automated sorting

system of plastics for recycle has already existed in the

industries as shown in Figure 1. Some systems may

have very high-tech sorting methods. While others use

simpler ones. In this case, the performance of the

automated sorting systems may vary to each other.

Meanwhile, some existing systems have a big structure.

This might cause the space uses to install the system

become larger. More space was used to locate

machineries of the system. Thus, the proposed design of

the system is focus on low to medium size of recycling

industry that need to be less spacious. The objectives of

this project are to design automated sorting system in

manufacturing industries of plastics for recycling and to

optimize the dimensions and space requirement for

proposed design.

Figure 1 Existing of plastic and colour sorting system

2. METHODOLOGY

The beginning step to design an automated sorting

system is by generating the conceptual design. A

concept usually expressed as a sketch or as a rough

three-dimensional model and is often accompanied by a

brief textual description [3].

Figure 2 shows conceptual design A that uses two

conveyors. First conveyor is to move recyclables from

unsorted container onto the conveyor belt. The second is

conveyor belt that transmits the recyclables to the

sorting area. The ejection method uses multiple

compressed air guns. There are two sensors mounting

above and crossing the conveyor belt. Conceptual

design B uses hopper placed at beginning of the

conveyor as shown in the Figure 3. The sensor placed at

the side and followed by the ejector. The non-PET

recyclables will be ejected into the non-PET bin located

opposite to the ejector and PET recyclables will

continue to flow until it drops into PE bin located at the

end of the conveyor.

For conceptual design C (Figure 4), sensors are

placed across the conveyor. It uses compressed air

ejector to eject non-PET recyclables away from

conveyor flow into the non-PET bin. The hopper is

place beside the conveyor. It has plates to control the

recyclables flow rate and slide to allow recyclables exit

onto the conveyor.

From the concept screening matrix shown in Table

1, conceptual design C has the highest score and is

ranked in the first place. Therefore, it will be chosen for

the detail design process and development.

Mat et al., 2017

133

Figure 2 Conceptual design A.

Figure 3 Conceptual design B.

Figure 4 Conceptual design C.

Table 1 Concept screening matrix.

Concept Existing

design Selection criteria A B C

Size - + + -

Ease of use 0 0 0 +

Sorting method + - - +

Ejection method - - + 0

Hopper position + + - -

Ergonomics 0 0 0 0

Safety 0 0 + +

Durability + 0 0 +

Sorted container position - + + 0

Sensor position + - + 0

Sum +’s 4 3 5 4

Sum 0’s 3 4 3 4

Sum –‘s 3 3 2 2

Net score 1 0 3 2

Rank 2 3 1 -


The assembly design of the system consists of

combination of single part and sub assembly is

visualized as in Figure 5. There are some development

activities done in designing the system such as

designing the slider of the hopper to have the

mechanism to control the flow rate of the recyclables.

The vision detecting system (sensor) is used for plastic

detection method that capable to identify type of plastic

bottles. The proposed design has a compact size and

reduce the requirement for space usage. The proposed

design of the system is 2.5 m in length and 1.2 m width.

It will utilize the area for placing just about 3 m².

Compared to the existing design which has 10.5 m

length and 4.5 m width and utilize the area of 47.25 m².

Therefore, the proposed design has managed to reduce

the space usage requirement for placing the machine.

Figure 5 Final design.

When review on the sorting rate, the proposed

design has 900 kg/hour of sorting rate. It is relatively

low compare to the existing design which has 2000

kg/hour of sorting rate. This is because the sorting and

ejection method for both designs are different. The

existing design uses multiple ejectors and can have the

multiple flows of the recyclables. For the proposed

design, it just has single ejector and only can manage

single recyclables flow. However, the sorting rate of

proposed design is acceptable for the low to medium

recycling industry.

4. CONCLUSION

From the data and information gathered through

literature review, conceptual designs of the system were

generated. By using concept screening matrix, concept

C was selected and developed so that it optimizes the

space usage when installation for low to medium size of

operation. In addition, the proposed design of the

automated sorting system for plastic recycling has a

suitable sorting rate required by low to medium size

recycling industry.

REFERENCES

[1] D. A., Wahab, A., Hussain, E., Scavino, M.M.,

Mustafa, and H., Basri, “Development of a

prototype automated sorting system for plastic

recycling”, American Journal of Applied Science,

vol. 3, pp. 1924-1928, 2006.

[2] P., Dinger, “Automated microsorting for mixed

plastics”, BioCycle, vol. 33, pp. 79-82, 1992.

[3] K. T., Ulrich, and S. T. Eppinger, “Product Design

and Development”, 3rd ed. University of

California: Mc Grow Hill. pp 97-136; 2003.


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Flexible shield for impact resistant purpose: A conceptual design H.M.S. Firdaus1,2,*, M.Y. Halyani1,3, M.I.H.C. Abdullah1,2, O.M. Rafi1,2

1) Faculty of Engineering Technology, Universiti Teknikal Malaysia Melaka,



3) Centre for Robotics and Industrial Automation, Universiti Teknikal Malaysia Melaka,



Keywords: Protective shield; impact resistant; RULA-analysis

ABSTRACT – The aim of this research is to develop

conceptual design of a shield for impact resistant. The

methodology used are customer survey, house of

quality, morphological chart, Rula-analysis and Pugh

method. Slide-in shield has been selected as conceptual

design based on material suitability since it used

polycarbonate that has very high Izod impact strength

between 600-850 J/m. In addition, it is also ergonomics

with the final score of 3 in Rula-Analysis for kneeing

and standing position. The main advantage of this shield

is the adjustable total length which lies in between 60-

100 cm.

1. INTRODUCTION

Shields were often the trusted defence of

infantrymen and knights alike throughout history and

this certainly did not change during the middle Ages.

Strong shields were used to block both attacks and

projectiles from harm to the soldier. After that, the plate

armour became a commonplace form of protection. It

was basically layered with the paste and tanned to make

it tougher [1]. Moreover, other equipment that compiles

with the shield were short throwing spear, open-face

helmet, and a sword [2]. Nowadays, demonstrations,

public disorder, and riots always happen in daily life for

a number of reasons such as economic hardships, social

injustices, ethnic differences (leading to oppression),

objections to world organizations or certain

governments, political grievances, and terrorist acts [3].

In certain years, the lightweight shield earned high

demand in the industry to lead to the personal

protection. Materials such as non-metallic materials,

ceramics and composites, have been increasingly

incorporated into more efficient lightweight armours

[4]. There are many factors that contribute to the quality

of the shield which includes size, thickness, and

material. The size varies greatly because some are

intended to protect the whole body, and others are meant

to be easily moved to cover specific parts at any given

moment. The objective of this study is to generate a new

conceptual design of a shield that is flexible and

lightweight to be used in accordance with the body of

the users.

2. METHODOLOGY

The project started by conducting customers

survey in defining customers needs. The feedback

received was generally in terms of maintenance,

material, shape, weight, handling, and function. The

needs were compared to engineering characteristics in

producing product design specification. Concept

generation was started by defining function analysis in

the morphological chart. Then, the best concept was

chosen from the analysis using Pugh Method [5]. In the

end, the body posture of the user in standing and

kneeing position was analyzed using Rula-analysis.

Figure 1 shows the details flow for the conceptual

design.

Figure 1 Flowchart for flexible shield conceptual

design.


Figure 2 shows the House of Quality for the shield.

There are 8 customers’ needs to be discussed which are

costs, lightweight shield, flexibility, ease to carry, ease

of storage, ease of use, comfortability, and durability.

All of the information are obtained from several ways

includes brainstorming, historical data, literature review,

and a deep discussion with experts [6].

Firdaus et al., 2017

135

Figure 2 House of quality.

Product features also consist 8 features which are

impact strength, ergonomic factor, size, thickness, mass,

added function, portability, and safety. According to

George and Linda [5], engineering characteristics can be

ranked by summing up all relationships of each

characteristic. The most importance engineering

characteristics led by impact strength and weight of

shield. They were followed by size and ergonomics

factor that shared the same rank. Weight is also

important because it is strongly related to ergonomics

factor in terms of shield handling by the users. There are

5 types of shield used for ergonomics analysis. Figure 3

shows mannequin in standing and kneeing positions.

Figure 3 Rula-analysis in standing and kneeing position.

Figure 4 Score for kneeing position.

For standing position, wrist and arm has a score of 3 for

slide in shield. The final score is also 3, which is less

compared to the other types of shield. While for kneeing

position, both posture and wrist and arm have a score of

4. However, the final score of 3 showed that the shield

weight and positioning are still acceptable for the users.

Figure 5 Score for standing position.

4. CONCLUSIONS

Impact strength is the most important criteria in

creating shield with high impact resistance.

Polycarbonate has been selected as material because it

possesses high impact strength. It also has considerably

low mass of approximately 1.44 kg. In addition, the

height of the shield is adjustable between 60 cm to 100

cm because slide in type has been chosen for the design.

The design has made it flexible for all type of users. In

terms of ergonomics based on Rula-analysis done in

standing and kneeing position, the final score for slide

in shield is 3. This average score is acceptable and can

still be improved.

5. ACKNOWLEDGEMENT

PJP/2015/FTK(34C)/S01459.

6. REFERENCES

[1] H. Adam, K. Jeremy, R. Daniel, and S. Alex, The

evolution of arms and armors during the crusades,

Thesis; 2013.

[2] K. Donald and F.V. Gregory, Men of bronze:

hoplite warfare in ancient Greece, Princeton

University Press; 2013.

[3] R. Joseph, Security Officer Study Guide, Lulu

Enterprises; 2014

[4] Z. Fawaz, W. Zheng, and K. Behdinan, “Numerical

simulation of normal and oblique ballistic impact

on ceramic composite armours,” Composite

Structures, vol. 63, no. 3–4, pp. 387–395, 2004.

[5] E. D. George and C. S. Linda, Engineering Design,

Fourth Edition, McGraw-Hill, 2009.

[6] S. Praveen, “House of Quality; An effective

approach to achieve customer satisfaction &

business growth in industries,” International

Journal of Science and Research, vol. 5, no. 9, pp.

1365-1371, 2016.


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The analysis of design product preferences using curve fitted profiling

H. Sihombing1,*, W.N. Hidayah1, S. Shamsuddin 2, M.Y. Yuhazri1

1) Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka,

Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Faculty of Mechanical Engineering, Universiti Putra Malaysia,

43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.


Keywords: Kansei engineering; bezier curve; mathematical approach

ABSTRACT – This study discussed about the

characteristics of product design based on customer

emotional preferences related to the ‘Kansei

Engineering’ towards ‘the Curve Fitted Profiling' using

mathematial approach. The focus of this project is

identify and analyze the customer preferences

compared to the image manipulated of product into

Bezier curves. This study use 20 city cars design in the

developed questionnaires were distributed in Malaysia.

From the data gathered, this study found that the

customer characteristics can be identified through the

certain variables of the Bezier curves equation. In this

study, the mostly preferences of city car profile design

is VW car.

1. INTRODUCTION

In today's aggressive market, the company has to

carry out the relevant strategy in order to fulfill their

customers' needs [1]. All companies have to, therefore,

prioritize their 'real extraordinary' consciousness to

catch customer design preferences before to produce a

certain product. According to Hsiao et al., this is due to

the paradigm of product designs that have to move from

the production-oriented approach to a marketing-

oriented approach, and finally to a customer-oriented

approach [2].

In addition, since the customers are not only to

demand the quality of product (but also their

satisfaction in psychological emotion conditions about

the product to be purchased), it is therefore, important

for producer to employ the improvement approaches in

their product development in order to satisfy their

customer needs and feelings. The companies that are

able to develop a product to fulfill their customers’

needs (that meet their psychological needs) will be

benefited to a profitable return when the product goes to market [3]. In this perspective, the Kansei Engineering

methods have been developed to support the valuation

of customer’s satisfaction in order to understand the

customer’s needs and desire [4]. However, this is only

limited on how to interpret the customer emotional

articulation refers to design of product. This study,

therefore, suggest the interpretation of the design

product related to profile using mathematical approach

related to profile, that is Bezier curve.

2. METHODOLOGY

Figure 1 shows the car design profiling

identification and measurement through segmentation.

By using segmentation into 4 quadrants, this study

activates the fitted curve profiling using 2 Bezier curve

for every quadrant.

Figure 1 Profiling the segmented of product car design

(side view).

Every cars profile was measured using curve fitted

to determine each mathematical values of every Bezier

curve. In this study, every car design is interpreted into

8 cubic Bezier curve. The cubic Bezier equation as

follows:

Bn (t) = An(1 - t )3+3Bn(1 - t)2 t +3Cn(1 - t)t2+Dnt3 …. (1)

Where n=1, 2,..,8 represents of each x-axis and y-axis

based on Bezier (n) equation.


Table 1 shows the numbers of survey respondents

towards the car design preferences in table 2. Based on

survey distributed to 168 respondents at 5 states in

Malaysia (which are Kota Bharu (KB), Temerloh (TM),

Kemaman (KMM), Kuala Terengganu (KT) and Melaka

(MLK)), the highest number of choices is VW Polo,

followed by Toyota Etios Liva, and Toyota Aygo (Table

3).

Sihombing et al., 2017

137

Table 1 Total sample of 168 respondents.

State KB TM KMM KT MLK

Total Sample 30 32 30 30 46

Table2 Name of 20 city car design.

No. Car brand No. Car brand

1. Perodua Axia 11. Suzuki Splash

2. Mitsubishi Mirage 12. Toyota Etios Liva

3. Toyota Aygo 13. Opel Adam

4. VW Polo 14. Ford KA

5. Hyundai i10 15. Fiat 500

6. Nissan Micra 16. Geely Panda

7. Aston Martin Cynet 17. Kia Picanto

8. Chevrolet Spark 18. Peugeot 108

9. Datsun Go 19. Fiat Punto

10. Honda Brio 20. Chery QQ

Table 3 Selection of city car (side view) at 5 states.

CAR NAME KB TM KMM KT MLK TOTAL

VW Polo 15 8 14 10 18 65

Toyota Etios Liva 20 10 9 10 49

Toyota Aygo 10 12 13 35

Mitsubishi Mirage 9 14 23

Honda Brio 11 11 22

Based on the curve variables from each of 8 Bezier

equations towards 20 cars design, the profiling is

constructed through the normalization values (based on

scale defined) towards the average values. Since the

range value is maximum value minus minimum value,

the normalization is conducted using equation as below:

∑N

∑

BnRange

=Min -Max (2)

Where Bn is the parameter values of Bezier, n is the

numbers (n=1,2,…8), while N is the total of values of

Bezier parameter based on x-axis and y-axis.

In this study, the segmentation of every variable

values based on single individual Bezier curve were

scaled in 5 distance ranges. Based on the most car

design choices (for an example), this study found as

shown in Table 4 in which the range of the car

preferences (using Bezier 1) is in the yellow color

marks (or 1). This meant that the specific parameter

values which make the VW Polo chosen rather than else

is due to the values of D1 in x-axis for Bezier 1, which is

in the range 2. Whiles, towards the values of C1 for x-

axis of Bezier 1 is related to the choices of VW Polo

and Mitsubishi Mirage as the car design preferences of

Melaka respondents which is influenced also by the

value of A1 in y-axis.

Table 5 showed that the choice of VW Polo is also

due to variable of A2 and B2 in x-axis. Whiles, C2 and

D2 in y-axis were related to design of Toyota Etios Liva

Melaka respondents chose none.

Table 4 Range for Bezier 1.

Car Name X - Axis Y - Axis

A1 B1 C1 D1 A1 B1 C1 D1

VW Polo 5 3 2 2 5 5 5 5

Toyota Etios Liva 2 1 1 1 3 2 1 1

Toyota Aygo 2 2 1 1 3 2 2 3

Honda Brio 1 1 1 1 3 5 4 5

Mitsubishi Mirage 4 2 2 1 4 2 2 4

Table 5 Range for Bezier 2.

Car Name X - Axis Y - Axis

A2 B2 C2 D2 A2 B2 C2 D2

VW Polo 4 4 3 3 4 4 2 2

Toyota Etios Liva 2 1 1 1 1 1 1 1

Toyota Aygo 2 1 2 2 2 2 2 2

Honda Brio 2 1 3 2 3 3 2 2

Mitsubishi Mirage 2 1 2 3 2 2 2 2

4. CONCLUSIONS

This study found that the manipulation process

towards the design profile into curve profile will help to

depict the certain values of curve parameters that

represent the uniqueness of respondents' choices based

on the profile design of product. Using car product as a

case study, the distributed survey to 5 states (in

Malaysia) said that VW Polo has the highest choices

based on Kansei Engineering related to side view. This

can be tracked refers to Bezier curve fitted towards the

product profiles. This study, however, need to be

extended to further investigate relate to design features

with many different views, such as front view, back-rear

views, etc.

ACKNOWLEDGEMENT

The authors would like to thank CRIM-UTeM and

RMC-UPM. This study is supported by Research Grant

RACE/F3/TK6/FKP/F00301.

REFERENCES

[1] N. Cross, Engineering Design Methods: Strategies

for Product Design, 3rd ed. Chichester, UK: Wiley;

2000.

[2] S.W. Hsiao, F.Y. Chiu, S.H. Lu, “Product-form

Design Model Based on Genetic Algortihms,”

International Journal of Industrial Ergonomics,

Vol. 40, No. 3, pp. 237-246, 2010.

[3] M.D. Shieh, T.H. Wang, C.C. Yang, “A Clustering

Approach to Affective Response Dimension

Selection for Product Design,” Journal of

Convergence Information Technology, Vol. 6, No.

2, pp. 197-206, 2011.

[4] A.M. Lokman, “Design & Emotion: The Kansei

Engineering Methodology,” Malaysian Journal of

Computing, Vol. 1, No. 1, pp. 1-11, 2010.


__________


Optimization of process parameters variation on ION and VTH in n-channel double gate FinFET device

N.K. Norddin, F. Salehuddin*, N.R. Mohamad, Norhisham Mansor, A.S.M. Zain, K.E. Kaharudin,

A.H. Afifah Maheran, A.R. Hanim, H. Hazura, S.K. Idris

Centre for Telecommunication Research and Innovation, Faculty of Electronics and Computer Engineering,

Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia.


Keywords: Threshold voltage; drive current; Taguchi method

ABSTRACT – In this research, we investigated the

process parameters variation on drive current (ION) and

threshold voltage (VTH) in n-channel Double Gate

FinFET device. There are several input process

parameters were investigated such as poly doping dose,

poly doping tilt, S/D doping dose, S/D doping tilt, VTH

doping dose and VTH doping tilt. The setting of process

parameters was determined by using L18 orthogonal

array in Taguchi Method. From n-channel Double gate

FinFET MOSFET device, the VTH and ION obtained after

the optimal approach is 0.479V and 1.31mA/µm

respectively. The results obtained are well within the

ITRS 2013 prediction for the electrical characteristics.

As a conclusion, the optimal solution for the robust

design recipe of the device was successfully achieved.

1. INTRODUCTION

The Planar MOSFET structure is reaching its

scaling limits and alternative devices are being

investigated to further increase the transistor density and

performance of the device. However, as the transistor

shrunk, the close proximity between the source and the

drain reduces the ability of the gate electrode to control

the potential distribution and the flow of the current in

the channel region and produce undesired effect called

the short channel effects (SCEs). In a continuous effort

to increase the current drive and reduce the SCEs, the

MOSFET has evolved from the classical planar single

gate device to multiple gate structure device either

double-gate, triple gate or quadruple gate [1]. Among

the double gate MOSFET, FinFET have emerged as the

most desirable alternatives to MOSFET due to its

simple structure and ease of fabrication. Process

variations have become a critical issue in today’s high-

performance circuit design as technology keeps scaling

down. As technology continues to scale down, process

variation has a more significant impact on circuit

performance. Small dimension devices operating at low

supply voltages show an in increased sensitivity to

parameter variations. It is, therefore, essential to

characterize and control the parameter fluctuations to

improve the performance and yield of integrated

circuits. The increased process parameter variation has

been recognized as one of the major roadblocks to

further technology scaling. According to Kaharuddin et.

al. [2], one of the most systematic and efficient ways to

achieve a robust design is to use an optimization method

of designing experiments based on Taguchi Methods.

Taguchi Methods provide the most efficient and viable

solution in such cases with minimal experimental trials

[3]. In this work, n-channel Double Gate FinFET device

is developed by using Silvaco TCAD simulation

software, where the effects of process parameter

variation are investigated using L18 orthogonal array in

Taguchi method. This method is utilized to reveal the

ideal level of process parameter for the higher ION value

of the Double Gate FinFET device. At the end of study,

it was found that the optimum solution closer to the

desired value as well as within the ITRS 2013 for the

year 2016 [4].

2. MATERIALS AND METHODS

The research is based on simulation and program

development and physical modelling of nano device

performance. A statistical method that is used in this

research needed to run several experiments with

different combination of the parameters to get the

desired output response that fulfills the statistical

method requirement. There are two noise factors were

varied for two levels to get four readings of the output

responses for every row of experiments. The values of

the noise factor at the different levels are listed in Table

1. The process parameters and their level that has been

identified for the experiment are shown in Table 2.

Table 1 Noise Factors and their level. Symbol Noise Factor Unit Level 1 Level 2

Y Gate Oxide Temperature °C 875 880

Z Poly Oxide Temperature °C 910 915

Table 2. Process Parameter and their level

Sym Process

parameter

Unit Level 1 Level 2 Level 3

A Poly Doping

Dose

Atom

cm-3

3.50e14 3.60e14 -

B Poly Doping

Tilt

Degree 15 16 17

C S/D Doping

Dose

Atom

cm-3

1.12e18 1.22e18 1.32e18

D S/D Doping

Tilt

Degree 73 74 75

E VTH Doping

Dose

Atom

cm-3

1.85e13 1.95e13 2.05e13

F VTH Doping

Tilt

Degree 6 7 8

Norddin et al., 2017

139


Figure 1 shows the two dimensional (2D) double

gate structure of a n-channel FinFET MOSFET device.

In this research, VTH of the device belongs to the

nominal-the-best quality characteristics and ION belong

to the larger-the-best quality characteristics. The S/N

ratio (SNR) is selected for VTH value must be closer or

equal to a given target value, that is 0.453V. Meanwhile

the S/N ratio that is selected for ION value must be the

largest value as possible. The SNR (dB) for each level

of the process parameters and factor effects on SNR (%)

for VTH and ION is summarized in Table 3. According to

this table, Factor B (35%) and Factor E (86%) was

found to be the major factor affecting the VTH and ION

respectively. Basically, the larger the SNR, the quality

characteristic of VTH and ION are better [5].

Figure 1 2D double gate structure of a n-channel

FinFET MOSFET device.

Table 3. SNR for threshold voltage and drive current.

Ou

tpu

tt

Res

po

nse

ss

Pro

cess

Para

met

er SNR (dB)

Fact

or

Eff

ects

on

SN

R (

%)

Level 1 Level 2 Level 3

Th

resh

old

Vo

ltage

(Nom

ina

l-th

e-b

est)

A 26.12 25.33 - 20

B 25.06 25.76 26.34 35

C 25.69 25.65 25.83 0

D 25.39 25.73 26.04 9

E 25.14 26.21 25.80 25

F 25.83 25.67 25.66 0

Dri

ve

Cu

rren

t

(La

rger

-th

e-b

est)

A -26.89 -25.39 - 0

B -26.92 -27.56 -23.94 14

C -25.32 -27.75 -25.35 0

D -25.42 -27.68 -25.31 0

E -31.75 -25.10 -21.57 86

F -25.35 -25.33 -27.75 0

The individual optimum condition for VTH and ION

were compared to choose the best optimization value for

each of the process parameters. The optimal value is

chosen due to the high percentage contribution of SNR

for each process parameter [4]. The best set of the

process parameters for device that had an effect on VTH

and ION is A1,B3,C3,D2,E2,F2. Once of the optimal

level of the process parameter is selected, the

confirmation test is performed to verify the accuracy of

the statistical method. The SNRs of VTH and ION for a

device after optimization approaches are 27.70dB

(28.47 to 26.78dB) and 2.31dB (2.41 to 2.21dB)

respectively. The values are within the predicted range.

Table 4 shows the comparison between the estimated,

simulation and the ITRS 2013 prediction values. This

indicates that the simulation value is closer to the

estimated value. Therefore, this verifies that the

simulated value is highly correlated with the estimated

result. This value of VTH is closer to ITRS prediction

and still in range ±12.7% of the nominal (target) value,

0.453V. Meanwhile, ION of the device exceeds the

minimum value which is 681µA/µm as specified in

ITRS 2013 for the year 2015 [4].

Table 4 Comparison between the estimated, simulation

and the ITRS 2013 prediction values. Output

Response

Estimation Simulation ITRS 2013 for

the year 2015

VTH (V) 0.482 0.479 0.45312.7%

ION (mA/µm) 1.29 1.31 > 0.681

4. CONCLUSIONS

Through this study, the factors that most affect the

output response of 18nm n-channel Double gate FinFET

MOSFET devices have been identified and the optimum

factor levels were also determined. Polysilicon Doping

Tilt and Threshold Doping Dose were found to be the

most significant factor that affects the threshold voltage

and drive current of device respectively. The threshold

voltage and drive current for a device after optimization

approaches are about 0.479V and 1.31mA/µm

respectively. These values have reached the target.

ACKNOWLEDGEMENT

The authors would like to thank the Ministry of

Higher Education (MOHE) and CeTRI, Universiti

Teknikal Malaysia Melaka (UTeM) for sponsoring this

study under the research grant

(RAGS/1/2014/TK03/FKEKK/B00064).

REFERENCES

[1] Rajiv Sharma, “Analytical modelling of volume

inversion and channel length modulation in fully

depleted double gate nanoscale SOI MOSFETs,”

Journal of Electron Devices, vol. 18, pp. 1553-

1563, 2013.

[2] K.E. Kaharudin, A.H. Hamidon, F. Salehuddin,

“Design and optimization approaches in double

gate device architecture,” International Journal of

Engineering and Technology (IJET), vol. 6, no. 5,

pp. 2040-2079, 2014.

[3] M.S. Phadke, Quality Engineering Using Robust

Design, Pearson Education, Inc. and Dorling

Kindersley Publishing, Inc; 2001.

[4] ITRS 2013 report, http://www.itrs.net

[5] H.A. Elgomati, B.Y. Majlis, I. Ahmad, F.

Salehuddin, F.A. Hamid, A. Zaharim, P.R. Apte,

“Application of Taguchi method in the

optimization of process variation for 32nm CMOS

technology,” Australian Journal of Basic and

Applied Sciences, vol. 5, no. 7, pp. 346-355, 2011.


__________


Reliability testing of inertial measurement units in the analysis of physiological variables in archery

Z. Taha1, R.M. Musa1,2,*, M.R. Abdullah2, M.H.A. Hassan1, M.A.M. Razman1, A.P.P. Abdul Majeed1

1) Innovative Manufacturing Mechatronics and Sports Lab, Faculty of Manufacturing Engineering,

Universiti Malaysia Pahang, Pekan Campus 26600, Malaysia 2) Faculty of Applied Social Sciences, Universiti Sultan Zainal Abidin, 21300, Terengganu, Malaysia


Keywords: Archery; inertial measurements units; physiological indicators

ABSTRACT – Archery is a static sport. Detection of

any movement is beneficial in ensuring shooting

accuracy. Thus, determining the reliability of any

detection instrument is paramount. This study aims to

ascertain the postural balance, hand movement,

muscular activation as well as heart rate of an archer

using Shimmer sensors. An archer was observed over

two different tests (A&B). Test A with free movement

while B with restricted movement.

Kolmogorov/Smirnov test was utilized to measure the

reliability of the sensors over test re-test in two different

tests. The Kolmogorov/Smirnov test re-test reveals a

significant difference between all the indicators in both

tests A and B, p < 0.001. IMUs sensors appear to be

reliable in measuring some physiological indicators in

the sport of archery.

1. INTRODUCTION

Current innovative advances reinforce the

utilization of inertial measurement units (IMUs) as a

practical alternative for the appraisal and measurement

of exercise performance beyond the motion analysis

laboratory [1]. These IMUs offer various potential

points of interest over conventional marker-based

frameworks; they are little, cost-effective, simple to set-

up and empower the appraisal of human movement in

an unconstrained situation [2]. This implies that these

universal advancements may have the capacity to

possibly quantify human movement and give feedback

with respect to the nature of the movement performed

[3].

IMUs have been utilized in various ways from

evaluating energy expenditure [4]; to gait analysis [5] to

medical observation [6]. These sensors have

additionally been utilized in the athletic field and sports

such as skiing [7] and golf [8]. Recently, the usage of

IMUs as a technique for tracking gym and rehabilitation

exercises have been examined. Lin and Kulić assessed

data collected from IMUs at the hip, knee and ankle

during various lower limb works out. Information from

the IMUs were utilized to estimate joint angles; with the

authors comparing the IMU-derived joint angles to

those quantified via a marker-based motion analysis

capture system [9]. Despite, the aforementioned

development, however, the reliability of such sensors

are often neglected or not reported.The purpose of the

present study is to test the reliability of IMUs sensors in

measuring the postural sway, hand movement, muscular

activation as well as heart during execution of archery

related techniques.

2. METHODOLOGY

A total of 4 IMUs Shimmer sensors were used in

the present study to determine the postural balance,

movement of the bow, muscular activations of the

muscle flexor digitorum and extensor digitorum as well

as the heart rate of the archer. The experimental

protocol was implemented in two parts. In first part

(Test A), the archer was instructed to sway from the

center of his gravity while holding the bow meanwhile,

in the second part (Test B), the archer was permitted to

limit the movement so as to enable the researcher to

discover whether the sensors have the ability to

differentiate the selected physiological indicators in the

two types of the postural positions. Two shimmer

sensors were attached to the left muscle extensor

digitorum and the right muscle flexor digitorum to

obtain Electromyography (EMG) signals during the

performances of the archery related movements

described previously. All the data were streamed in real

time at a sampling rate of 51.2Hz using an Android

phone and transmitted via Bluetooth for further analysis.

The areas of all the sensors attachments on the archer’s

body are shown in Figure 1.

Figure 1 IMUs sensors’ location attachments on the

archer’s body.

mailto:[email protected]

Taha et al., 2017

141

2.1 Data analysis

The Kolmogorov/Smirnov test was applied to

measure the reliability of the application over test re-test

between tests A and B of all the movements measured at

a confidence level of p ≤ 0.05. The data for the total of

five body actions were analyzed and evaluated using

MATLAB 2016a and XLSTART add in version 2014

USA for Windows.


Table 1 indicates the inferential statistics of the

Kolmogorov/Smirnov test. Two periods of testing,

observations, D-statistics as well as p values are shown.

It can be extracted from the table that the p-value of all

the tests (1 - 5) were < 0.001 which explains that there

is statistically significant difference between tests A and

B of all measured actions. This confirmed the reliability

of the sensors in evaluating as well as discriminating the

two types of movement executed by the archer.

Table 1 Inferential statistics of the

Kolmogorov/Smirnov test.

Test-retest Obs. D P value

1. Bow Movement Test A 0.24 0.001*

Test B

2. Postural Sway Test A 0.49 0.001*

Test B

3. Muscle Ex.Activation Test A 0.3 0.001*

Test B

4. Muscle Flex.Activation Test A 0.27 0.001*

Test B

5 Heart Rate Test A 0.47 0.001*

Test B

*Significant at p < 0.001

The finding of the current study is in agreement

with previous researchers who reported that IMUs had

been used in various ways such as evaluating energy

expenditure, gait analysis and medical observation [4-

6]. These sensors have additionally been employed in

the athletic field and sports such as skiing and golf [7-8].

Moreover, the findings from the present study are also

congruent with the study conducted by other researchers

who assessed data collected from IMUs at the hip, knee

and ankle during various lower limb works out.

Information from the IMUs were utilized to estimate

joint angles; with the authors comparing the IMU-

derived joint angles to those quantified via a marker-

based motion analysis capture system. The researchers

presumed that these joint angles were precise when

contrasted with those acquired by means of the most

conventional methodology [9].

4. CONCLUSION

The current study has successfully evaluated

postural sway, hand movement, muscular activation as

well as heart rate attributed to sport of archery in two

different analyses. The sensors used in the study have

demonstrated high sensitivity in detection of any

movement executed by the archer which is beneficial in

analyzing any form of movement during both aiming

and releasing of arrow. The study has indicated that

inertial measurement units can be utilized to evaluate

movements employed by the archers. The sensors are

capable of providing information on every action

executed which can go a long way in helping the archers

to be aware of his/her movements and any incorrect

techniques to help improve performance.

ACKNOWLEDGEMENT

The researchers wish to thank the National Sports

Institute of Malaysia for providing the grant for the

current study (ISNRG: 8/2014-12/2014). The

researchers have no conflict of interest to declare.

REFERENCES

[1] A. Ahmadi, E. Mitchell, F. Destelle, M. Gowing,

N.E OConnor, C. Richter, K. Moran. “Automatic

activity classification and movement assessment

during a sports training session using wearable

inertial sensors,” 11th IEEE International

Conference on Wearable and Implantable Body

Sensor Networks, pp. 98-103, 2014.

[2] O. Giggins, D. Kelly, B. Caulfield. “Evaluating

rehabilitation exercise performance using a single

inertial measurement unit,” in Proceedings of the

7th International Conference on Pervasive

Computing Technologies for Healthcare. Institute

for Computer Sciences, Social-Informatics and

Telecommunications Engineering, pp. 49-56, 2013.

[3] I. Pernek, K.A. Hummel, P. Kokol. “Exercise

repetition detection for resistance training based on

smartphones,” Personal and Ubiquitous

Computing, vol. 17, no. 4, pp.771-782, 2013.

[4] E.S. Rawson, T.M. Walsh. “Estimation of

resistance exercise energy expenditure using

accelerometry,” Med Sci Sports Exerc, vol. 42, no.

3, pp. 622-8, 2010.

[5] J.J. Kavanagh, H.B. Menz. “Accelerometry: a

technique for quantifying movement patterns

during walking,” Gait Posture, vol. 28 no. pp. 1-

15, 2008.

[6] M. Zhang, A.A. Sawchuk. “A customizable

framework of body area sensor network for

rehabilitation,” in 2009 2nd International

Symposium on Applied Sciences in Biomedical and

Communication Technologi. Nov, 2009.

[7] F. Michahelles, B. Schiele. “Sensing and

monitoring professional skiers,” IEEE Pervasive

Computing, vol. 4, no. 3, pp. 40-45, 2005.

[8] H. Ghasemzadeh, V. Loseu, R. Jafari. “Wearable

coach for sport training: A quantitative model to

evaluate wrist-rotation in golf,” Journal of

Ambient Intelligence and Smart Environments, vol.

1, no. 2, pp. 173-184, 2009.

[9] J.F. Lin, D. Kulić. “Human pose recovery using

wireless inertial measurement units,” Physiol

Meas, vol. 33, no. 12, pp. 2099-115, 2012.


__________


Wing design for blended-wing-body aircraft M.H. Mat Yazik*, M.T.H. Sultan, A. Hamdan

Aerospace Manufacturing Research Centre, Faculty of Engineering, Universiti Putra Malaysia,

Selangor Darul Ehsan, Malaysia


Keywords: Distribution; blended-wing-body aircraft; pro-verse yaw

ABSTRACT – Blended-Wing-Body (BWB) aircraft is

a new design pitched as the future of air transport.

However, due to the nature of the design that is

relatively new, more research has to be made to exploit

its advantages. This article studies an initial scaled

blended wing body and the effect of different lift

distribution on a BWB design. The initial design is

adjusted via twist to obtain desired wing loading

distribution. Aerodynamic optimization is performed on

Selig S5010 aerofoil to further improve the

aerodynamic performance of the BWB design.

1. INTRODUCTION

Reservoir and effect on global warming is the main

concern for both industry and environmentalist.

Although significant improvement in efficiency with the

introduction of winglets and high performance engine,

the conventional tube-wing configuration has reached

its limits. A step change in fuel efficiency may be

realised through un-conventional configuration. The

demand for better and more efficient aircraft calls for

blended-wing-body (BWB) design as next generation

aircraft design to tackle the problem. Compared to tube-

wing design, BWB has advantage aerodynamically

through lower wetted area to volume ratio and lower

interference drag. BWB also have better lift-to-drag

ratio compared to conventional design credit to the

fuselage that also contribute to the total lift of the

aircraft. Having low radar cross sectional area makes

them fit into military aircraft which require stealth

aircraft i.e. reconnaissance and bomber mission. For

example, the Northrop Grumman B-2 Spirit which

employ the flying wing design. However, the

advantages in aerodynamic performance can only be

realised through detailed shape design of the BWB

shape.

Despite having advantage over cruise efficiency,

BWB design has poor stability control due to the lack of

tail surface control. Problem arise when BWB is require

to perform a roll. The effect of induced drag over a

finite wing aircraft will produce adverse yaw when

aircraft perform a rolling motion. This is caused by

increase in induced drag on one wing which cause the

aircraft to yaw in opposite direction then intended roll

motion. The objective of this paper is to study the effect

of span wise distribution on aerodynamic efficiency and

overcoming adverse yaw problem. Research has been

made to enable control of flight dynamics through

implementation of surface deformation to produce

different in lift between the wings. This eliminate the

need for vertical control surface which would introduce

additional trim drag [1]. Qin et al. investigate a series of

aerodynamic study on span wise lift distribution of a

blended wing body aircraft within a European

Commission funded project [2-3].

2. METHODOLOGY

The initial BWB design is divided into three

sections which are

a. The center body: from 0 to 0.12m

b. A pair of mid-wing: from 0.12 to 0.25m

c. A pair of outer-wing: from 0.25 to 0.55m

The baseline design has root chord is 0.39m and

tip chord of 0.052m. Figure 1 shows the planform of the

design BWB, showing dimension of the section location

at each span location. The cruise operating condition is

stated in Table 1. All aerodynamic analysis is analyzed

based on cruise operating condition.

Figure 1 BWB Baseline geometric planform.

Table 1 Cruise design condition.

The baseline geometry has no twist and dihedral

applied to it. Selig S5010 aerofoil has been chosen

along the span because it is designed for low Reynolds

number and it has near zero pitching moment coefficient

which is suitable for longitudinal stability of BWB

design. The airframe is analyzed in XFLR5 using 3D

panel method to obtain its aerodynamic properties.

Different load distribution is applied to the baseline

BWB through geometric twist across the span to

observe the effect of different lift distribution on the

Cruise Condition Unit Value

Altitude m 11500

Speed kmh-1 100

Reynolds number 440 090

Design lift coefficient 0.203

Yazik et al., 2017

143

aerodynamic performance. The aerofoil profile were

further optimized for improvement of aerodynamic

performance. The aerofoil optimizer program XOptFoil

is used to optimize aerofoil shape at cruise operating

condition. All of the design are analyzed using Athena

Vortex Lattice (AVL) program to obtain the stability

derivatives yawing moment with respect to roll, 𝐶𝑛𝑝.

The analysis was made at 25ᵒ bank angle to obtain a

standard aircraft banking rate of 3ᵒ per second.


Figure 2 shows the distribution local lift along

then

Half-span for cruise condition. The bell shape has a

slightly longer span compared to elliptical distribution

as proposed by Jones and Bower et al. for a solution to

achieve optimum structural efficiency with fixed total

lift and root bending moment [4]. The load distribution

is achieved through geometric twist throughout the

span. As we can see the bell-shaped distribution have

maximum local lift shifted toward the root section. The

bell-shape distribution has its max local lift coefficient

around 0.25m. The movement of max local lift

coefficient towards the root reduce potential for tip

stalling and reduce wave drag at high speed flight.

Figure 2 Local lift distribution across half-span.

Table 2 compares the aerodynamic performance of

each design at cruise condition. The elliptical perform

the best among the designs in term of induced drag due

and total drag as expected according to research made

by Prandtl in [5]. Aerofoil optimization prove to be

beneficial to the aerodynamic performance of BWB

design as we can see a decrease in drag coefficient and

induced drag coefficient.

Table 2 Aerodynamic performance of BWB designs.

BWB Design C L C D C Di

Baseline 0.20291 0.009781 0.002055

Elliptical 0.20294 0.009677 0.001995

Optimized

Elliptical 0.20296 0.008814 0.001987

Bell-Shaped 0.20301 0.011308 0.002793

Optimized Bell-

Shaped 0.20290 0.010161 0.002833

Contradict to the aerodynamic performance, the

pitching moment and pro-verse yaw performance in

elliptically loaded BWB is worse than the bell shaped

loaded BWB. The pitching moment obtained from

elliptical loaded wing is further from zero compared to

the others. This require surface control to trim the

aircraft which introduce additional trim drag to the

BWB. The design also has negative yaw-roll

derivatives. This indicate that the BWB will yaw in

opposite direction of rolling motion. This is usually

compensating by vertical tail. With bell-shape wing

loading, the stability derivative appears to be positive

thus does not require vertical tail.

Table 3 Moment coefficient and Stability derivatives of

BWB design.

BWB Design C m C np

Baseline -0.010615 -0.004785

Elliptical -0.016271 -0.006549

Optimized

Elliptical -0.020069 -0.002903

Bell-Shaped 0.010201 0.012558

Optimized Bell-

Shaped 0.008097 0.017857

4. CONCLUSION

From this experiment, it can be concluded that

both load distribution has advantage for BWB design.

BWB with elliptical load distribution have higher

aerodynamic performance and lower induced drag

compared to bell-shaped load distribution. This can

translate to lower fuel consumption, higher range and

more efficient cruise flight. On the other hand, bell

shaped wing loading have advantage over the elliptical

shaped loading as it provides pro-verse yaw to the BWB

design. This is beneficial for a BWB design which lack

vertical tail. A more efficient design is one that can

employ both distributions packed in a single BWB

design. As future works, a morphing concept for BWB

aircraft can be developed to realize the design in which

currently under investigation by the author.

ACKNOWLEDGEMENT

GP-IPB grant no. 9490602.

REFERENCES

[1] W. Wu, D. Chen, N. Qin, X. Peng, X. & X. Tang,

“A new efficient control method for blended wing

body,” International Journal of Modern Physics:

Conference Series, vol. 19, pp. 396-405, 2012.

[2] N. Qin, A. Vavalle, A. Le Moigne, M. Laban, K.

Hackett & P. Weinerfelt, “Aerodynamic

considerations of blended wing body aircraft,”

Progress in Aerospace Sciences, vol. 40, no. 6, pp.

321-343, 2004.

[3] N. Qin, A. Vavalle, & A.L. Moigne, “Spanwise lift

distribution for blended wing body aircraft,”

Journal of Aircraft, vol. 42, no. 2, pp. 356-365,

2005.

[4] R.T. Jones, “The spanwise distribution of lift for

minimum induced drag of wings having a given

lift and a given bending moment,” 1950.

[5] L. Prandtl, “Uber tragflugel des kleinsten

induzierten widerstandes,” Zeitshrift fur

Flugtechnik und Motorluftschiffahrt, 1933.


Improving manufacturing facilities design layout for a coffee production company

D. Ibrahim*, S.M. Hashim, A.I.S. Yusof, Y. Yaakob, N. Hussin, A.A. Azahari

Faculty of Mechanical Engineering, Universiti Teknologi MARA, Kampus Permatang Pauh, Pulau Pinang, Malaysia


Keywords: Layout; system layout planning (SLP); machine utilization

ABSTRACT – This study is to assist a local coffee

production company to increase their production due to

higher demands of Robusta coffee. There is high flow

intensity between workstations which have high

interrelationship leading to high traveling time. Two

alternative layouts are proposed using the 11 steps in

Systematic Layout Planning (SLP). The proposed

layouts involve re-position the Cooking, Breaking,

Grinding and Sifting workstations for both layouts. The

layouts are then evaluated using DELMIA QUEST

simulation. The best alternative is chosen based on the

most significant improvement in term of machines

utilization and total output produced.

1. INTRODUCTION

A well-designed facility layout must provide great

connections between raw materials, labors, equipment

and finished goods. Other than that, it must be at lowest

possible costs and in safe working environments.

Systematic implementation can result a reduction of

10% to 30% of the company’s operating cost [1]. This

study intends to propose to a small local coffee making

company an alternative layout that is possible to provide

better machines utilization and increase the number of

output produced to meet their customer’s demand.

2. METHODOLOGY

Systematic Layout Planning (SLP) developed by

Richard Muther consists of eleven steps to develop

several solutions, that can be divided into six basics

steps which is chart of relationships, establish space

requirements, diagram activity relationships, draw space

relationship layouts, evaluate alternative arrangements

and detail the selected layout plan [2, 3]. To generate a

layout that meets the requirements, Delmia Quest is

used as a tool in this study to improve elements such as

bottlenecks and idle time that the SLP method failed to

identify and could not solve. Delmia Quest contains

material element for modeling such as machines, buffer,

process, failure rate, maintenance, labor, path and

material export, which can help users simulate and

analyze the process flow in 3D facilities environment

[4].

2.1 Systematic layout planning

The first step of SLP is gathering the input data

required for the case study. The input variables are

product (2 in 1 Robusta Coffee); output per day (200

boxes); routing in the company’s existing production

layout; service available including utilities, equipment,

restrooms, lockers, cafeteria, entrances, and exits; and

working time (8 hours/day). The results are tabulated in

an Activity Relationship Chart (ACR). The relationship

chart displayed which department are related to others

and it also rates the importance of the closeness between

them. The degree of closeness between departments was

rated by using Total Closeness Rating (TCR) as shown

in Table 1.

Table 1 Total closeness rating.

Value Closeness

A Absolutely Essential

E Especially Important

I Important

O Ordinary

U Unimportant

X Not Desirable

ACR in Figure 1 is generated where proximity and

relationships are visually evident. After constructing the

ACR, the space requirements needed for each process

can be determined for the actual layout. Systematic

Layout Planning (SLP) is best employed when creating

a new facility starting from scratch and the design was

not yet finalized. In this case study, the existing facilities

were established hence there was limited ability to

expand the area for extra space.

Figure 1 Activity relationship chart (ACR).

Ibrahim et al., 2017

145

2.2 Layout simulation

The effectiveness of the improved layout is

evaluated from total output and machine utilization.

The simulation is based on ten processes involved to

produce the product that shares with 22 machines which

required different process time. The simulation run time

is to reflect the actual scenario of one working shift

which of 420 minutes including one 60-minute lunch

break. In this study, three models are constructed and

simulates using the DELMIA QUEST V5. One is the

existing layout while the other two are the proposed

alternatives. The existing production layout of the

company was modeled to get the benchmark of the

machine utilization and the number of output produced

per day.


For the first alternative layout, the cooking and

breaking departments are placed close to each other. The

grinding machines are placed in a straight line to reduce

material handling time after mixing process as well as

enable to place the sifter machines closer to it. The

roasting and packaging departments remain at the same

location. In the second alternative layout, the cooking

and breaking departments are rotated for 90ᵒ counter

clockwise to reduce traveling time for worker to load

the materials to the cooking machines. The grinding and

sifting departments remain the same as in Alternative 1.

The roasting and packaging departments remain the

same as the existing layout.

The simulation results comparisons in Table 2 for

existing layout, Alternative 1 and Alternative 2 for

Robusta coffee, shows that the machine utilization of

the cooking process for Alternative 2 is more by about

1.5% compared to Alternative 1 and 3% increase

compared to the existing layout. This is due to the less

distance travel for the worker to load the materials to the

machines. The work-in-process (WIP) product produced

is still the same but the material handling time is

reduced. There is no significant change for breaking

process due to waiting time increased for breaking

process to finish before loading the next batch.

Table 2 Machine utilization for robusta coffee.

Process Element Existing

Layout

Alternative

1

Alternative

2

Cooking Cooker 1 55.96% 57.14% 58.87%

Cooker 2 55.87% 57.14% 58.66%

Cooker 3 52.93% 54.76% 56.02%

Breaking Breaker 1 68.77% 68.77% 68.83%

Breaker 2 68.56% 68.57% 68.41%

Breaker 3 68.04% 68.09% 68.25%

Grinding Grinder 1 60.71% 65.47% 70.23%

Grinder 2 59.52% 65.47% 69.04%

Grinder 3 59.52% 64.28% 69.04%

Sifting Sifter 1 35.24% 40.71% 44.00%

However, for the grinding process, machine

utilization is approximately 4% more for Alternative 2

compared to the Alternative 1 and approximately 9.5%

more than the existing layout. This is due to the closer

machines position and less material handling time

causing the worker to run the process faster.

Consequently, sifting process machine utilization also

increased due to the closer and better position between

grinding and sifting machines. The result shows 5.47%

increased for Alternative 1 compared to the existing

layout and 8.76% increased for Alternative 2 compared

to the existing layout. Positioning breaking machines

closer to the mixer might contribute to this increment.

Hence, the material handling time is reduced.

Table 3 indicates that Alternative 2 produced more

than Alternative 1 and the existing layout.

Table 3 Total Output of Robusta Coffee.

Layout Simulation (Boxes)

Existing Layout 175

Alternative 1 180

Alternative 2 197

4. CONCLUSIONS

In relation to the research objectives, the proposed

layout indicated that the performance of the company

can be improved with a well-designed facility layout.

Significant result might be achieved if flexibility for

future design changes is incorporated and interactions

between facilities and material handling system is

considered when designing layouts.

REFERENCES

[1] F. De Carlo, M. A. Arleo, O. Borgia, and M. Tucci,

“Layout Design for a Low Capacity Manufacturing

Line : A Case Study Regular Paper,” pp. 1–10,

2013.

[2] C. R. Shah, “Increased Productivity in Factory

Layout by Using Systematic Layout Planning

( SLP ),” Int. J. Adv. Eng. Technol., 2013.

[3] R. Muther, Systematic Layout Planning, Second

ed. MA, Boston: Cahners Books, 1973.

[4] E. G. Boteanu, “Improving layout and workload of

manufacturing system using Delmia Quest

simulation and inventory approach,” Int. J. Innov.

Res. Adv. Eng., vol. 1, no. 6, pp. 52–61, 2014.

Proceedings of Mechanical Engineering Research Day 2017, pp. 146-147, May2017

__________


Particles influence on breakdown voltage of liquid insulating medium M.H.S. Zainoddin*, H. Zainudin, N. Abu Bakar

1) Research Laboratory of High Voltage Engineering, Faculty of Electrical Engineering,

UniversitiTeknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia


Keywords: Metallic particles; non-metallic particles; breakdown voltage

ABSTRACT – This paper presents the experimental

results of a comparative study of mineral oils, synthetic

and natural ester oils through breakdown voltage (BdV).

These dielectric liquids were contaminated with two

types of particles, metallic and non-metallic particles and

experimental results indicate that the AC breakdown

strength of insulating liquid are higher when it

contaminated with non-metallic particles. The influence

of metallic particles on the AC breakdown strength of

insulating liquid with lower viscosities are less sensitive

and the difference between mineral insulating oil and

vegetable insulating oil were obtained and analyzed to

find the prominent type of particles that strongly affected

the insulating liquid performance.

1. INTRODUCTION

Nowadays, the demand for vegetable insulating

liquid is increasingly as dielectric liquid in transformers,

however it is vulnerable to particles and special attention

need to be paid to the influence of particles on its

dielectric strength.

As a coolant and insulating medium that widely

used in transformers, the dielectric liquid must maintain

and maximize its performance to ensure the safe

operation of power transformer. According to CIGRE

working group WG 12.17, a significant number of high

voltage transformer failures were attribute to the present

of contaminant. It is known that dielectric liquids will be

in direct contact with the internal components of the

transformers such as insulation papers, iron cores and

metals [1]. This leads to the presence of impurities in the

dielectric liquids such as cellulose pressboard and iron

particles due to thermal and electrical stresses present

when the HVAC transformers are in service [2].

Besides that, previous studies found that the

breakdown voltage of ester are influenced by metallic

particles to a less degree than mineral oil [3]. Due to

different in molecular structures and viscosity, the effect

of metallic and non-metallic particles is different and it

should be attached a great importance. A comparative

study has been done to investigate the prominent type of

particles between metallic and non-metallic particles.

2. EXPERIMENTAL ARRANGEMENT

AC BdV of dielectric liquids were measured in an

electrode configuration which according to the ASTM

D1816-04 standard. All the tests were conducted under

room temperature and at atmospheric pressure. Two

spherically-capped electrodes with 36 mm diameter each

with 1 mm gap between electrodes is used throughout the

experiment. As discussed in previous section,

contaminant or impurity is an important factor that

influences the BdV of dielectric liquids. The type, size,

concentration level of contaminant in dielectric liquid

will affect it BdV performance and strength. So, two type

of contaminant with similar size (500 μm) and similar

concentration level (0.001g) were added after the

dielectric liquid was dried and degassed to indicate the

particle presence in dielectric liquid. The contaminated

dielectric liquids were stirred for 2 minute at room

temperature. Then, AC BdV test of contaminated

dielectric liquids were measured by using MEGGER

OTS60PB throughout the experiment. For the purpose

of statistical and visualization analysis, 50 breakdown

data are determining for each sample.


The objective of this experiment is to evaluate the

effect of contaminant on the dielectric liquid

performance. Figure 1,2 and 3shows AC BdV results for

Gemini X, Midel 7131 and MideleN. It can be seen that

from Figure 1, at the first place, when the oil samples

without contaminant, the level of BdV are higher for all

three types of dielectric liquid compared when the

insulating liquid tested with metallic and non-metallic

particles as shown in Figure 2 and 3. Previous research

has drawn that vegetable oil has comparable dielectric

strength as mineral oil. However, finding from

experimental results clearly shown that BdV of two type

of ester oil are lower compared with traditional mineral

oil. This situation is believed due to the BdV properties

of the dielectric liquid itself which is different for every

dielectric type.

Figure 1 Distribution of breakdown voltage of tested

liquids without contaminant.

Zainoddin et al., 2017

147

Figure 2: AC breakdown voltages of dielectric liquids

contaminated with carbon particles.

Figure 3: AC breakdown voltages of dielectric liquids

contaminated with copper particles.

4. CONCLUSION

The present work focuses on the influence of

metallic and non-metallic particles on the breakdown

strengths of insulating liquid and its difference between

ester insulating oil and mineral insulating oil. Carbon

particles and copper particles with similar size and

concentration level were added into insulating oils and

then the AC breakdown voltages were measured. The AC

breakdown voltage of ester oils are higher and reduce

significantly when the non-metallic particles than those

of mineral oil. Finding from the experimental results

shows that ester oil is more sensitive to the metallic and

non-metallic particles than mineral oil.

REFERENCES

[1] M.G. Danikas, “Breakdown of transformer oil,”

IEEE Electr. Insul. Mag., vol. 6, no. 5, pp. 27–34,

1990.

[2] X. Wang and Z.D. Wang, “Particle effect on

breakdown voltage of mineral and ester based

transformer oils,” Annu. Rep. - Conf. Electr. Insul.

Dielectr. Phenomena, CEIDP, pp. 598–602, 2008.

[3] X. Wang and Z.D. Wang, “Motion of Conductive

Particles and the Effect on AC Breakdown

Strengths of Esters,” 2011.


__________


Optimization of FDM process parameters for ABS spur gear build time S.M.M. Nor1,2,*, M.N. Sudin1,2, S.H.S.M. Fadzullah1,2, M.R. Alkahari1,2, F.R. Ramli1,2





Keywords: Optimization parameters; build time; fused deposition modeling

ABSTRACT –This paper presents optimization of

Fused Deposition Modeling (FDM) process parameters

such as layer thickness, infill density and fill angle to

achieve optimum build time for ABS spur gear by using

orthogonal array of Taguchi Method and signal-to-noise

(S/N) ratio analysis. From the results, it was found that

FDM parameters; layer thickness, fill angle and infill

density contribute to the build time performance of ABS

spur gear. It can be concluded that the optimized

parameter obtained in this study is 0.31mm of layer

thickness, 30% infill density 90° of fill angle in

minimizing the build time of ABS spur gear.

1. INTRODUCTION

Fused Deposition Modelling (FDM) enables quick

fabrication of 3D physical models directly from 2D

CAD data using layered manufacturing (LM) technique

by laying semi-molten plastic on a platform from

bottom to the top [1]. Besides, LM technique is widely

used by researchers in helping them to achieve the

required quality characteristic or the process

performance based on selection and optimal process

parameters [2]. Many researchers [2-4] had conducted

parameters optimization to obtain desired response

parameters such as build time, flexibility, surface

roughness and tensile strength respectively.

In Rapid Prototyping (RP) technology, build time

is seen as one of the key aspects of the quantitative

characteristic which is very important in calculating

production cost and also manufacturing durations. FDM

or RP has the ability in reducing product development

time [5]. Hence, this could be done by optimizing the

FDM parameters in order to obtain minimum build time

of a product. Therefore, investigations on FDM process

parameters to the build time of a spur gear are carried

out to achieve optimum build time.

2. METHODOLOGY

In this state, the 3D model was sliced into layers

with required thickness and other process parameters

were determined such as infill density and fill angle.

Semi-molten plastic such as Acrylonitrile Butadiene

Styrene (ABS) with diameter of 1.75mm was used as

FDM feedstock and extruded by the heated nozzle

which can be deposited on the bed as the nozzle travels

along the platform bed. 9 samples of ABS spur gear

were produced by using FDM while build time of 9 spur

gears were recorded and analysed by using analytical

software Minitab 17 for the S/N ratio analysis and

ANOVA. Confirmation test was carried out to verify

estimated result against experimental result by using

optimum parameter obtained from those analyses.

Another spur gear was produced by using the optimum

parameter and build time was recorded. This result was

used to verify estimated result whether it is strongly

correlated with the experimental result.

Figure 1 ABS spur gear.

In this experiment, layer thickness, infill density

and fill angle parameters are variable process

parameters while humidity and temperature were kept

constant. Layer thickness represents the height of the

sliced 3D model whereas fill density means the amount

of material deposited between the FDM parts and fill

angle is the method where roads can be deposited to fill

the interior part. In this experiment, the layer thickness

for level 1, level 2 and level 3 are 0.18mm, 0.25mm and

0.31mm respectively, were used whereas 30°, 45° and

90° were used for each level of the fill angle

respectively. Besides, previous studies had shown that

the infill density between 30%-90% were compliable

since the toughness of a part increases as the infill

density increases [6]. This experiment used Taguchi

method which proposed 𝐿9 Orthogonal Array of three

rows and nine columns with three process parameters at

three different levels.


The signal-to-noise ratio measures the sensitivity

of the quality investigated to those uncontrollable

factors in the experiment. The objective of this

experimental plan is to minimize the build time of ABS

Spur Gear. Hence, the smaller the better quality

Nor et al., 2017

149

characteristic was implemented [7]. The optimization

parameters can be further studied and analyzed in

Figure 2.

Table 1: Obtained S/N Ratio Values Experiment

No

Parameters Responses

Layer

Thickness

(mm)

Infill

Density

(%)

Fill

Angle

(˚)

Build

Time

(s)

SNRA

for

Build Time

1 0.18 30 30 11940 -81.540

2 0.18 60 45 25500 -88.131

3 0.18 90 90 19620 -85.854

4 0.25 30 45 12960 -82.252

5 0.25 60 90 19020 -85.584

6 0.25 90 30 25020 -87.966

7 0.31 30 90 10980 -80.812

8 0.31 60 30 15720 -83.929

9 0.31 90 45 20340 -86.167

As depicted in Figure 2, the combination of

parameters and their level’s, 𝐴3𝐵1𝐶3 has produced

maximum value of S/N ratio and it yields optimum

quality characteristics.

Figure 2 Graph of S/N effects of process parameters on

build time.

Based on the comparison data on both calculated

from experimental and equation model, the results

shown that, the average percentage error was 0.05%

with the reliability of 99.9%. This step is very

important and highly recommended by the Taguchi to

verify the test outputs.

4. CONCLUSION

It can be concluded that the optimized parameter

obtained in this study is 𝐴3𝐵1𝐶3 while infill density is

the most significant parameter in minimizing the

processing time of ABS spur gear.

ACKNOWLEDGEMENT

Grant no.: (FRGS/1/2015/TK03/FKM/02/F00628).

REFERENCES

[1] F. Ning, W. Cong, Y. Hu and H. Wang, “Additive

manufacturing of carbon fiber-reinforced plastic

composites using fused deposition modeling:

Effects of process parameters on tensile

properties,” Journal of Composite Material, pp. 1-

12, 2016

[2] M. Srivastava, S. Maheshwari and T.K. Kundra,

“Optimization of Build Time and Model Volume

for A FDM Maxum Modeler Using Response

Surface Methodology,” International Journal for

Technology Research in Engineering, vol. 2, no. 7,

pp. 1050-1057, 2015.

[3] B.H. Lee, J. Abdullah and Z.A. Khan,

“Optimization of rapid prototyping parameters for

production of flexible ABS object,” Journal of

Materials Processing Technology, vol. 169, no 1,

pp. 54-61, 2005.

[4] M. Alhubail, D. Alenezi and B. Aldousiri,

“Taguchi-based optimisation of process parameters

of fused deposition modelling for improved part

quality,” International Journal of Engineering

Research & Technology, vol. 2, no. 12, pp 2505-

2519, 2013.

[5] R. Anitha, S. Arunachalam and P. Radhakrishnan,

“Critical parameters influencing the quality of

prototypes in fused deposition modeling,” Journal

of Materials Processing Technology, vol 118, no.

1-3, pp. 385-388, 2001.

[6] C. Mendonsa, K.V. Naveen, P. Upadhyaya and

V.D. Shenoy, “Influence of FDM process

parameters on build time using Taguchi and

ANOVA approach,” International Journal of

Science & Research., vol. 4, no. 2, pp. 2013-2016,

2013.

[7] N. Raghunath and M. Pandey, “Improving

accuracy through shrinkage modeling by using

Taguchi method in selective laser sintering,”

International Journal of Machine Tools &

Manufacture, vol. 47, no. 6, pp. 985-995, 2007.


__________


Behavior analysis of human walking and robot movement for person following robot

A.I. Tarmizi1,2,*, A.Z.H. Shukor1,2, N.M.M. Sobran1,2, M.H. Jamaluddin1,2

1) Faculty of Electrical Engineering, Universiti Teknikal Malaysia Melaka,

Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Centre for Robotics and Industrial Automation, Universiti Teknikal Malaysia Melaka,



Keywords: IMU sensor; human walking; person following robot

ABSTRACT – Person Following Robot (PFR) is

generally used to accompany or assist human while

following the human’s movement. This paper presents

the analysis on the behavior of human walking

movements and robot movements. This experiment is

done for designing the tracking algorithm of PFR. The

analysis is done by extracting data from human walking

and mobile robot movement by using IMU sensor.

Human walking data is compared to the robot movements

data and analyzed. The speed of the normal human

walking is faster than the robot used in this research.

1. INTRODUCTION

PFR has three main important parts which are robot

hardware, tracking and following algorithm. The

hardware that often used for PFR is a mobile robot [1-2].

Whereas sensor fusion is often used in PFR for tracking

the human. Other than that, there are a lot of following

algorithm that used in PFR. For example, behavior based

algorithm and also fuzzy controlled algorithm.

This paper will be focusing on behavior analysis on

human walking for tracking part of the PFR. To be able

to track the human walking, the human walking behavior

is needed to be analysed. The human walking behavior is

analysed by its movement pattern of turnings on different

paths and also the speed. This analysis of human walking

and robot movements on different paths are important so

that it can be used to further applying fuzzy decision

making. Fuzzy decision making will classify each data to

be able to decide on different tasks to be done. This paper

aims to analyse the behavioral movement of human

walking and to compare with the robot movement on a

path for PFR.

2. PFR TRACKING EXPERIMENTAL SETUP

The robot used in this research is Pioneer AmigoBot

mobile robot. The max speed of this robot according to

the specification is 1m/s. However, the max speed of this

robot by experiment is 0.5m/s. In this research, the speed

of 0.5m/s is used for the straight-line path, whereas the

other that have turns, 0.4m/s speed is used. This is

because the turning radius increases when the robot

moves at its maximum speed resulting the robot not able

to go along the path. Contrarily, the normal human walk

speed is around 0.7m/s to 0.8m/s. PFR should be able to

follow a person either the robot need to be faster, same

speed, or a slightly slower than the human.

3. DATA EXTRACTION

To collect and analyze human walking movements

using IMU sensor different path in this research,

MPU6050 and Arduino UNO are used. Arduino UNO is

set up with coding that will extract yaw value in degree

from the IMU sensor. The Arduino and MPU6050 can be

connected to ZigBee for wireless connection. The

MPU6050 is put on the waistline of the subject. The

subject is required to walk normally on different paths of

walking straight, right turn, left turn, U-turn to the right

and lastly U-turn to the left. The data from the human

walking movements are recorded.

As for extracting the data of robot movements, IMU

sensor is put on the center of AmigoBot robot. AmigoBot

is controlled by a remote host from a computer to move

across the same path as the human walking. The

MPU6050 displays the yaw values of the movements and

the data are recorded. The human walking and the robot

movements data are collected and analyzed in two

separate experiments. Lastly, the recorded human and

robot data are then compared and analyzed.

4. DATA ANALYSIS

The data are analyzed by plotting the data extracted

from the human walking and robot movement on a same

graph. The data from the graphs plotted are the degree of

yaw turning and the time taken in milliseconds. From the

yaw data, the human and robot turning movements are

analyzed by observing the pattern of the graphs. Other

than that, the graphs are also analyzed in terms of speed

and time taken for the human and robot to complete one

path. The turning movement and time taken for the robot

and human to finish one path are discussed and compared

with each other. Lastly, feature extraction of standard

deviation and mean absolute value is applied for further

process of data classification by using fuzzy decision

making.


The data from the IMU sensor are plotted in a graph

comparing the robot and human movement (Figure 1-5).

The distance of the path is kept constant with the same

path. The graphs are in linear graph so that the data can

Tarmizi et al., 2017

151

be observed and analyzed clearly. Moreover, the data is

more stable in a linear graph.

Figure 1 Human-robot moving straight.

Figure 2 Human-robot turning right.

Figure 3 Human-robot turning left.

Figure 4 Human-robot U-turn to the right.

Figure 5 Human-robot U-turn to the left.

The graphs above show different results on the

human walk and the robot movement on path. According

to the results, the turning movements of the human-robot

is quite similar with each other. However, the robot has a

sharper turning movement than human walking. From the

graph, human walking has a smoother turning

movements than the AmigoBot because the AmigoBot

was remotely controlled from the computer. The

smoothness of turning movement can be reduced by

programming the AmigoBot to move accordingly to the

path instead of remotely controlled. On the other hand,

the time taken of the human and robot to complete one

path has a slightly time difference. From the graphs, it

shows that the human walking is faster than the robot

movements. This can be seen on the graph where the time

taken for the human to complete on path is shorter than

the robot.

Table 1 and table 2 above are the feature extraction

applied to the data extracted from the IMU sensor. Table

1 shows the results for the standard deviation calculation

for the data extracted. Besides that, table 2 resulted by

calculating the mean absolute value of the data extracted.

From the data, mean absolute value calculation gives a

better value to be used for further data classification by

using fuzzy decision making.

Table 1 Feature extraction using standard deviation.

Path Human Robot

Straight 15.19 26.54

Turn right 54.15 35.27

Turn left 29.81 14.81

U-turn (right) 89.67 69.39

U-turn (left) 71.58 51.78

Table 2 Feature extraction using mean absolute value.

Path Human Robot

Straight 22.91 46.03

Turn right 62.23 61.69

Turn left -22.17 9.081

U-turn (right) -29.06 -13.42

U-turn (left) -61.71 -24.11

Tarmizi et al., 2017

152

6. CONCLUSION

As a conclusion, the movement of turning and

maneuverability of the robot is the same human walking.

This can be seen by analyzing the pattern of the graphs

that looks similar to each other. However, according to

the graph, we can see that the speed of the robot is slightly

slower than the human walking speed.

ACKNOWLEDGEMENT

This research is supported by the grant

RAGS/1/2014/TK03/FKE/B00056. Thanks to the

Robotics and Industrial Automation group, CeRIA.

REFERENCES

[1] C.A. Cifuentes, A. Frizera, R. Carelli, T. Bastos,

“Human-robot interaction based on wearable IMU

sensor and laser range finder,” Robotics and

Autonomous Systems, vol. 62, no 10, pp. 1425-

1439, 2014.

[2] S. Jia, L. Wang, S. Wang and C. Bai, “Fuzzy-based

intelligent control strategy for a person following

robot,” In Robotics and Biomimetics (ROBIO),

2013 IEEE International Conference on, pp. 2408-

2413, 2013.


__________


Roughness of 3D printed surface under influence of chemical post processing

A.R. Zolkaply1, M.R. Alkahari1,2,*, F.R. Ramli1, 2, N.S. Hamdan3, M.N. Sudin1, 2



Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 3) Faculty of Engineering Technology, Universiti Teknikal Malaysia Melaka,



Keywords: 3D printing; additive manufacturing (AM); surface roughness

ABSTRACT - Fused deposition modeling (FDM) is a

popular technology in 3D printing. This is due to its

capability to fabricate 3D part faster, effectively,

economically and more user-friendly. However, the

yield of the printed part is poor in surface finish and it

produces staircase effect resulted from layer by layer

deposition process. Hence, this paper studies the effect

of methyl ethyl ketone (MEK) used as post-processing

treatment for acrylonitrile butadiene styrene (ABS) 3D

printed part. During the experiment, controlled amount

of MEK was applied on 3D printed surface after

printing process. This research discovers that the surface

finish of 3D printed ABS can be improved significantly

with the use of MEK.

1. INTRODUCTION

The ability of fused deposition modeling (FDM) in

producing 3D part is undeniable and this technology has

brought a breakthrough in industries. However, FDM

fabricated part is less accurate due to its staircase issue

that affects the final quality of a prototype [1].

Performance of FDM process is also not comparable to

conventional manufacturing process [2]. This problem

can be reduced with several approaches such as slicing

strategy, parameters optimization and post-treatment [3].

According to Galantucci et. al., chemical treatment can

be used to reduce surface roughness on 3D printing

fabricated part and increasing the compactness of

structure [4]. The usage of chemical like dimethyl

ketone (Aceton) and methyl ethyl ketone (MEK) solvent

can be used to react with acrylonitrile butadiene styrene

(ABS) to improve the surface finish [5]. This method is

less expensive and easier.

One of the methods for post-processing techniques

is vapor polishing that is used as surface treatment by

coating the printed part evenly without affecting the

dimensional accuracy significantly. The treatment

makes the solvent react with ABS layers, which fused

together and reform a new structure that produces a

smooth surface finish. This also can increase cohesion

between layers and affects the mechanical properties of

ABS [6]. In this research, MEK was applied on 3D

printed surface as post processing and its influence on

surface roughness is studied.

2. METHODOLOGY

The experiment was implemented on Mendel Max

3D printer. Specimens were fabricated using ABS

thermoplastic and were post-processed with MEK. A

roller was designed to roll the injected solvent on the

ABS surface evenly. The purpose of using roller was to

reduce ABS dimensional changes during post-treatment

process. Chemical MEK was used to dissolve the ABS

filament. MEK is an organic solvent that has an ability

to break chains of amorphous thermoplastic like ABS

which is low in chemical resistance. The volume of

MEK was varied in order to investigate the effect of the

chemical amount on the surface roughness of 3D printed

surface. The initial reading of surface roughness for an

untreated sample was taken and the value was recorded

at 9.98 μm. Seven samples were fabricated on Mendel

and the volume of applied MEK was varied from 1 ml

to 7 ml. The top and cross section view was taken by

using Nikon Measuring Microscopes MM-800. The

parameter setting was set up as in Table 1.

Table 1 Parameter setting for 3D printing.

Volume, ml 1 2 3 4 5 6 7

Layer thickness, mm 0.2

Fill angle,˚ 90

Infill pattern Line

Infill density, % 30


Based on the result, using chemical treatment as

post-processing improves the roughness at certain

volume of MEK. The amount of MEK plays important

role in determining the roughness of the ABS. Figure 1

shows that the roughness reduces from Ra= 9.98 μm to

Ra= 0.861 μm when 1 ml of MEK applied on ABS.

91.4% of improvement is achieved and glossy effect to

the sample is produced. The MEK dissolves the ABS

surface and forms a strong intermolecular bond as the

MEK evaporates and it creates cohesive bonding on

ABS structure. As a result, the distance of printing line

become closer and the material bond as shown in Figure

2(b). The surface roughness worsens when the amount

of MEK increases. This shows that the high amount of

Zolkaply et al., 2017

154

MEK can increase the surface roughness where Ra

9.979 μm was recorded for 7 ml MEK. Figure 2 and

Figure 3 show inverted microscope photographs of

treated and untreated specimens that have a substantial

impact in their surface finish.

Figure 1 Treated and untreated surface roughness of

ABS part.

(a) (b)

Figure 2 Top view of ABS (a) sample before treated by

MEK (b) Sample after treated by MEK.

(a) (b)

Figure 3 Cross sectional view of ABS (a) sample before

treated by 1ml of MEK and (b) sample after treated by

1ml of MEK.

Figure 3 shows the sectional view of ABS where

reaction between MEK and ABS plastic produced a

reactant that fills in the air gap of the sample. This

makes the molecular chain to slide over each other and

reforms a new secondary bond with the presence of

MEK solvent. As a result, the new form of ABS

structure is produced with glossy effect on its surface.

MEK is used due to its properties that slightly high in

boiling point which can slow the evaporation process

during post-processing treatment. This ensures the

bonding process is completely done by the MEK to

dissolve the ABS filament before it forms a new

structure. The low chemical resistance property of ABS

has made its random structure to easily absorb chemical

and destroy its secondary bond if the usage amount of

the chemical is not controlled. For the MEK treatment,

it was observed that the amount of the chemical was

very important in order to produce high quality of

surface finish. The interaction of ABS and MEK

material shows drastic improvement in surface

roughness. This has proven that MEK is a solvent that

can be used to enhance the surface finish at the suitable

amount.

4. CONCLUSION

FDM has a high potential in various application

but its quality of printed parts needs to be improved.

The drawbacks of FDM surface roughness has

encourage introduction of various methods in improving

FDM parts. This research indicates that application of

MEK as post-processing on 3D printed surface enable

the surface roughness to be improved significantly. This

process is much easier and economical. However, the

amount of MEK applied on the surface need to be

controlled so that required roughness can be obtained.

ACKNOWLEDGEMENT

Grant no.: RAGS/1/2015/TK0/FTK/03/B00123.

REFERENCES

[1] N.V. Reddy and S.G. Dhande, “Slicing procedures

in layered manufacturing: A review,”

Rapid Prototyping Journal, vol. 9, no. 5, pp. 274-

288, 2003.

[2] N. S. A. Bakar, M. R. Alkahari, and H. Boejang,

“Analysis on fused deposition modeling

performance”, J. Zhejiang Univ. Sci. A, vol. 11, no.

12, pp. 972–977, 2010.

[3] L.M. Galantucci, F. Lavecchia, and G. Percoco,

“Experimental study aiming to enhance the surface

finish of fused deposition modeled parts,” CIRP

Annals - Manufacturing Technology, vol. 58, pp.

189-192, 2009.

[4] L.M. Galantucci, F. Lavecchia, and G. Percoco,

“Quantitative analysis of a chemical treatment to

reduce roughness of parts fabricated using fused

deposition modeling,”

CIRP Annals - Manufacturing Technology, vol. 59,

no. 1, pp. 247-250, 2010.

[5] R.A. Sambasiva, A.M. Dharap, J.V.L. Venkatesh,

and O. Deepesh, “Investigation of post processing

techniques to reduce the surface roughness of

fused deposition modeled parts,” International

Journal of Mechanical Engineering and

Technology, vol. 3, no. 3, pp. 531-544, 2012.

[6] H. Gao, D.V. Kaweesa, J. Moore, and N.A. Meisel,

“Investigating the impact of acetone vapor

smoothing on the strength and elongation of

printed abs parts,” Journal of the Minerals, Metals

and Minerals Society, vol. 22, no. 4, pp. 1-6, 2016.

0

2

4

6

8

10

12

1 2 3 4 5 6 7

Surf

ace

rou

ghn

ess,

Ra

(u

m)

Volume, V (ml)

Treated…

Untreated surface roughness, Ra=9.98 um


__________


An investigation on applying different types of adhesive to reduce warping deformation in open source 3D printer

M.A. Nazan1,*, F.R. Ramli1, 2, M.R. Alkahari1, 2, M.A. Abdullah1, 2, M.N. Sudin1, 2




* Corresponding e-mail: [email protected]

Keywords: Open-source 3D printer; synthetic and natural based adhesive; warping deformation

ABSTRACT – The purpose of this paper is to

investigate the warping deformation problem by

applying adhesive material instead of applying heat onto

the open source 3D printing bed. The research processes

involved investigating the power consumptions of open

source 3D printers, preparation of the 3D printing model

and adhesive material, tensile strength of adhesive

samples and warping deformation measurement. Based

on the result, the power consumption has decrease to

23W in average when heat is not applied to printing bed.

Epoxy resin based adhesive gives better warping

deformation with 0.8% and higher bonding strength of

1.2233 MPa compare to cassava and soy adhesive.

1. INTRODUCTION

One of the problems in the open source 3D

printing especially filament deposition modeling (FDM)

process is that the plastic filament which is extruded

from the machine nozzle tends to shrink and warp from

the printing bed platform. This problem can be reduced

by applying heat to the printing bed where, the higher

the bed temperature is, the less the deformed shape will

be [1]. Moreover, the warping deformation has also

showing warping reduction when applying epoxy resin

based adhesive onto the printing bed [2-3]. Other type

of adhesive such as cassava and soy based adhesive has

massive potential to be used in the same ways to reduce

or to eliminate the warping problem. . Hence, the

purpose of this paper is to study how warping

deformation problem can be reduced by applying

adhesive material on the printing platform instead of

heat.

2. METHODOLOGY

2.1 Power consumption

Three types of open source 3D printer models i.e.

Kossel Mini, Fab Gear and Mendel Max was used in

this experiment to identify total power used when the

machine use heat bed and how much when it is not.

Digital Power Reader 2.0 was attached to the printer’s

power source to record the power used. It was measured

while beginning from the first material deposit from

nozzle until the end of fabrication of a 30x100x5mm³

solid model using Polylactic Acid (PLA) material such

as in Figure 1. Two different setting has been used

which one with a heat bed and without heat bed. The 3D

printing parameters is set based on [3] where the infill

density is 13%, 192˚C of printing temperature, and

0.2mm of layer height.

(a) (b)

Figure 1 Rectangular shaped of (a) sketched in solid

model and (b) printed sample.

2.2 Warping deformation preparation

Next, the same PLA model in Figure 1 with the

same parameters is built by applying adhesive onto the

3D printer bed. Three types of adhesive were used

where epoxy resin based adhesive from [3], cassava and

soy based adhesives are prepared based on [4-5]. The

adhesive was spread diagonally across the printing bed

is with angle of 45˚ and in the opposite direction to span

it all over the surface.

Figure 2 is shows the method of measuring the

warping deformation by using vernier height gauge and

Equation (1) to calculate the percentage number that

come out while measuring the warping deformations for

each sample. By referring to the Eq.(1), the value of

warping deformation, y is obtained by the difference

value of 𝑦1 , value of total height and 𝑦2, the deflected

total height.

Figure 2 Method of measurement at each sample’s

corner.

𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑤𝑎𝑟𝑝𝑖𝑛𝑔

𝑑𝑒𝑓𝑜𝑟𝑚𝑎𝑡𝑖𝑜𝑛, 𝑦= |

𝑦1−𝑦2

𝑦1| 𝑥 100% (1)

Nazan et al., 2017

156

2.3 Mechanical testing

Standard test method for Tensile Strength of

Adhesive by Means Bar and Rod Specimens (ASTM

D2095) was used to obtain the bonding strength of the

adhesive. The specimens were prepared such as in

Figure 3 where a set of 10mm x 10mm x 40mm is

printed onto glass that was spread with different type of

adhesive. The specimens were undergoing tensile

strength test and the max stress and max strain were

recorded.

Figure 3 Tensile test sample arrangement.


3.1 Power consumption result

Figure 4 shows the power consumption of the

tested open-source 3D printers. All 3D printers took

about 43-44 minutes to complete their task. Mendel

Max 3D printer that use heat bed has the highest power

consumption with P = 59 W. In general, the power

consumption of the printers that using heat bed is

double compares to printing without heat bed. Thus, for

complex model that takes longer time and higher power

consumption, removing heat bed can benefit the user

cost and the effect towards the environment.

Figure 4 Power consumption of three type of open-

source 3D printer.

3.2 Warping deformation result

Figure 5 shows warping deformation percentage of

the different adhesive type when applied to 3D printing

bed. Epoxy resin based adhesive gives better adhesion

with about 0.5-1 times lower warping deformation

compares to cassava and soy based adhesive.

Figure 5 Warping deformation tests result by three

different adhesives.

This is expected because the epoxy resin adhesive

has better adsorption with plastic part and glass compare

to natural adhesives which do not have better adsorption

with the plastic part. In addition, humidity also plays

roles to the quality of natural based adhesive.

3.3 Tensile test result

Table 1 shows the result of the tensile test that had

been performed by using these adhesives. In

comparison, the epoxy resin based adhesive has better

tensile bond strength, σ = 1.2233MPa which is four

times better than the two natural adhesives. This

explains why the warping deformation is lower when

epoxy resin based adhesive was used in the experiment.

Table 1 Tensile test result at maximum load applied

Adhesive types Max. Stress,

σ (MPa)

Max. Strain,

ε

Epoxy 1.2233 1.0108

Cassava 0.3236 0.0221

Soy 0.1917 0.0046

4. CONCLUSION

As a conclusion, the investigation shows that the

power consumption has decreased to about half when

heat is not applied to the printing bed. Epoxy resin

based adhesive on printing bed without heat gives better

warping deformation compare to cassava and soy

adhesive because of its higher bonding strength.

However, both of the plant natural based adhesive

shows potential to solve the warping problem where the

obtained warping deformation is less than 10%.

ACKNOWLEDGEMENT

This research is funded under the research grants

FRGS/1/2015/TK03/FKM/02/F00270.

REFERENCES

[1] Y.H. Choi, C.M. Kim, H.S. Jeong, J.H. Yuon,

“Influence of bed temperature on heat shrinkage

shape error in FDM additive manufacturing of the

ABS-engineering plastic,” World Journal of

Engineering and Technology, vol. 4, no. 3, pp. 186-

192, 2016.

[2] F.R. Ramli, M.I. Jailani, H. Unjar, M.R. Alkahari

and M.A. Abdullah, "Integrated recycle system

Nazan et al., 2017

157

concept for low cost 3D-printer sustainability," in

Proceedings of Mechanical Engineering Research

Day, pp. 77-78, 2015.

[3] M.A. Nazan, F.R. Ramli, M.R. Alkahari and M.A.

Abdullah, "Optimization of warping deformation in

open source 3D printer using response surface

method," in Proceeding of Mechanical Engineering

Research Day, pp. 71-72, 2016.

[4] A.J. Gunorubon, “Production of Cassava Starch-

Based Adhesive,” Research Journal in Engineering

and Applied Sciences, vol. 1, no. 4, pp. 219-224,

2012.

[5] W.H. Wang, X.P. Li, X.Q. Zhang, “A soy-based

adhesive from basic modification,” Pigment &

Resin Technology, vol. 37, no. 2, pp. 92-97, 2008.


__________


Manufacturability of overhang structure using open source 3D printer M.R. Alkahari1,2,*, S.N.H. Mazlan1, O.I. Sun3, F.R. Ramli1,2, N.A. Maidin4 , M.N.Sudin1,2


Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Centre of Advanced Research on Energy, Universiti Teknikal Malaysia Melaka,

Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 3) Daikin Research &Development Malaysia Sdn. Bhd,

Taman Perindustrian Bukit Rahman Putra, 47000 Sungai Buloh, Selangor, Malaysia 4) Faculty of Engineering Technology, Universiti Teknikal Malaysia Melaka,



Keywords: Fused deposition modeling (FDM); overhang structure; additive manufacturing

ABSTRACT - Fused Deposition Modeling (FDM) is

the most common 3D process where parts are created

layer by layer. Recently, researchers started to study on

the different structure that FDM cannot fabricate such as

overhang structure. The objective of this paper is to

investigate the manufacturability of the overhang

structure at various lengths. The overhang structure is

designed and built using the open source 3D printer.

Then, the capability of the structure to be produced

according to its design is evaluated. Based on this, some

recommendation is presented to provide a guideline to

the 3D printer user.

1. INTRODUCTION

Fused Deposition Modeling (FDM) creates a part

layer by layer and offers a lot of potential benefits to the

use of plastic material because it can fabricate

mechanical complex structures in a shorten time and

low cost of manufacturing process. However, the

drawbacks of this system, it cannot fabricate the

overhang structure. Adam et al studied on the element

transition and aggregated structure in order to provide

the design rules for 3D printer user. The study also

compared capability of different 3D printing techniques

to fabricate the overhang structure [1].

Meanwhile, Mahesh et al studied on the

benchmarking design for evaluation in order to compare

the RP systems and process. The purpose benchmarks

consist of features called flat beam (FB) to evaluate the

overhang, flatness and straightness [2]. Paolo et al,

studied on the benchmarking of FDM machine through

part quality using IT grades to measure the dimensional

accuracy of benchmarking design and evaluate the

standard ISO basic size and Geometric Dimension and

Tolerance (GD&T) value [3]. Bakar et al analyzed FDM

performance by fabricating the benchmarking design

using high end AM 3D printer and measure the surface

roughness and dimensional accuracy of the printed

part [4].

2. METHODOLOGY

In this study, an overhang structure was fabricated

using open source 3D printer originated from the Prusa

3D printer. The material is a thermoplastic material,

polylactic acid (PLA). The structure has twenty-two

different overhang values. After the part was fabricated,

it was measured using the profile projector to compare

the dimension of CAD (Computer Aided Design) data

and the printed parts. In order to identify the suitable

length at the element transition (overhang), the qualities

of the manufactured test specimens were examined by

visual inspection and evaluated. The dimension of the

overhang length was taken according to the guide of “x”

as tabulated in Table 1.

Table 1 Details descriptions of the overhang feature.

Overhang Description

Feature

Guide Length, x

Dimension range x, mm 0.2 to 24


The visual inspection of an overhang structure was

tabulated in Table 2 after the part was fabricated. The

successfully built overhang structures were compared to

the nominal overhang length. The data were presented

in the terms of dimensional accuracy by comparing the

result from 3D CAD dimension and printed parts.

Figure 1 shows the 3D CAD data and the fabricated

parts of the overhang structure with different length, x

varied from 0.2 to 2 mm. Generally, the overhang can be

fabricated using a 3D printer but has limited maximal

length.

Based on the Figure 1, the overhang length, x

dimensional accuracy of overhang structure does not

deviate much as compared to the CAD data. The plotted

graph only contains the successfully fabricated

overhang by the range from 0.2 to 2.0 mm, meanwhile

for the rest, the measurements cannot be properly taken

due to the disturbance effect from the fabricated parts

because the parts has sagged and agglutinated filament

was formed underneath the layers. For overhang, the

mailto:[email protected]

Alkahari et al., 2017

159

hanging part should be short enough to ensure

manufacturability given by part layer filaments do not

“fall out” from its nominal position because built layer

by layer and each layer must be supported by something

underneath it or a build platform. The graphical trend

shows that, printed part from the 3D printer having the

value nearer to CAD data, especially when x≤2.0 mm.

Thus, some recommendations on the suitable length of

the overhang structure were proposed. Table 3 provides

the general guideline for 3D printer user for

manufacturing of overhang structure using the open

source 3D printer.

Table 2 Visual inspection of overhang quality.

Overhang length, mm Quality

0.2 Successfully fabricated










2.2 Sagging

4.0 Sagging

6.0 Sagging

8.0 Sagging

10.0 Sagging

12.0 Sagging

14.0 Serious fall out






Figure 1 Measured length of successfully fabricated

overhang structure.

Table 3 Length of overhang structure.

Design Not

Recommended Acceptable Recommended

Feature

Range,

mm x≥14 2.2≤x≥13 x≤2

Table 4 Visual images of overhang structure.

Design Not

recommended Acceptable Recommended

Parts

Quality Serious

fall out Sagging

Successfully

fabricated

4. CONCLUSIONS

FDM creates a parts layer by layer, thus it cannot

print hanging parts unless by generating the support

structure. However, overhang structure with minimal

overhang length of x≤2 is recommended to be

manufactured. When the length x>2, it may cause

sagging of filament and fall out which can cause the

structure to be built not be similar to the CAD design.

ACKNOWLEDGEMENT

The research was supported by research grant

RAGS/1/2015/2016/TK0/FTK/03/B00113.

REFERENCES

[1] G. Adam and D. Zimmer,"Design for Additive

Manufacturing—element transitions and

aggregated structures," CIRP Journal of

Manufacturing Science and Technology, vol. 7, no.

1, pp. 20-28, 2014.

[2] M. Mahesh, Y. Wong, J. Fuh and H. Loh,

"Benchmarking for comparative evaluation of RP

systems and processes," Rapid Prototyping

Journal, vol. 10, no. 2, pp. 123-135, 2004.

[3] P. Minetola, L. Iuliano, and G. Marchiandi,

“Benchmarking of FDM Machines through Part

Quality Using IT Grades”, Procedia CIRP, vol. 41,

pp. 1027–1032, 2016.

[4] N.S.A. Bakar, M.R. Alkahari, and H. Boejang,

“Analysis on Fused Deposition Modeling

performance,” J. Zhejiang Univ. Sci. A, vol. 11, no.

12, pp. 972–977, 2010.


__________


Design self-balancing bicycle N. Tamaldin1,2,*, H.I.M. Yusof1,2, M.F.B. Abdollah1,2, G. Omar1,2, M.I.F. Rosley2

1) Faculty of Engineering Technology, Universiti Teknikal Malaysia Melaka,

Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2) Center of Advance Research on Energy, Faculty of Mechanical Engineering,



Keywords: Self-balancing; gyroscope; control system

ABSTRACT – Recently, many investigations have been

done regarding to the problems of controlling two-

wheeled self-balancing robot. This paper reviewed based

on five previous journal in order to find out which

method is suitable to design a self-balancing bicycle and

it will focus on the control system of the structure. There

are several ways in order to design an efficient self-

balancing bicycle which are by using control moment

gyroscope (CMG), mass balancing, steering control and

reaction wheel. Based on previous research, the usage of

CMG is the suitable choice since it can produce large

amount of torque, it has no ground reaction forces, and

the system can be stable even when the bicycle is

stationary.

1. BACKGROUND STUDY

Bicycle is a common form of transportation,

recreation, and also can be a medium in exercising which

have been used for years of many people. Bicycle also

can serve to provide physical therapy, as they are a low

impact form of exercise that can train balance, strength,

stamina and coordination. Though one may consider

riding a bicycle to be a fairly simple task, this is not the

case for many people especially for young children, and

adults who have never learned to ride a bicycle, injured

people, or people suffering from developmental or

cognitive disabilities. A system that could provide

balancing assistance to a bicycle rider without otherwise

affecting the experience of riding a bicycle could provide

great benefit to these groups of individuals. Such a

system could be used both as a teaching tool, and as a

physically therapeutic device.

Recently, many investigations have been done

regarding to the problems of controlling two-wheeled

self-balancing robot, which are widely taken into

applications in the field of autonomous robotics and

intelligent vehicles. First and the foremost problem is

bicycle keep falling when it is not in controlled especially

at low forward velocity [1-2]. Besides, the lack of

controlling flywheels in the horizontal position also

become a problem in this cases. Without controlling the

flywheels in the horizontal position, the bicycle will lose

its balance after a particular limited flywheel’s angle [3].

So that, many inventors have been made research and

development to encounter this problem such as

introducing the self-balancing bicycle. Self-balancing

bicycle use sensors to detect the roll angle of the bicycle

and actuators to bring it into balance as needed, similar

to an inverted pendulum where it is an unstable nonlinear

system and can be implemented in several ways. This

paper reviewed based on five previous journal in order to

find out which method is suitable to design a self-

balancing bicycle and it will focus on the control system

of the structure.

2. METHODOLOGY

The methods to achieve a self-balanced bicycle are

mainly classified into four types. The first type is using a

control moment gyroscope (CMG) [1-4]. This method

can provide a large torque, but energy consumption of

CMG is very high because the flywheel is spinning all

the time. The CMG consists of a spinning rotor with a

large, constant angular momentum, whose angular

momentum vector direction can be changed for a bicycle

by rotating the spinning rotor. The spinning rotor, which

is on a gimbal, applies a torque to the gimbal to produce

a precession, gyroscopic reaction torque orthogonal to

both the rotor spin and gimbal axes. A CMG amplifies

torque because a small gimbal torque input produces a

large control torque to the bicycle

The second type is mass balancing where

mechanical structure of mass balancing is simple, but the

torque this method could provide is small.

The third type is steering control where a controller

controls the amount of torque applied to the steering

handlebar to balance the bicycle. Advantages of this

system are low mass and low energy consumption, while

its disadvantages are it requires ground reaction forces

and it cannot withstand large tilt angle disturbance. The

energy consumption of steering control is low, but it

cannot balance the bicycle at low forward velocity.

The forth type is using a reaction wheel where speed

of a reaction wheel is increased or decreased to generate

a reactionary torque about the spin axis which is parallel

to the bicycle’s frame [5]. As the bicycle begins to fall to

one side, a motor mounted to the reaction wheel applies

a torque on the reaction wheel, generating a reactionary

torque on the bicycle, which brings back the bicycle’s

balance. Advantages of this system are it is low cost,

simple and no ground reaction, while disadvantages are

it consumes more energy and it cannot produce large

amount of torque.

A very well-known self-balancing bicycle robot

using a reaction wheel is the Murata Boy which was

developed by Murata Manufacturing Co., Ltd in 2005.

Tamaldin et al., 2017

161

3. RESULTS AND ANALYSIS

Among these methods, the CMG, a gyroscopic

stabilizer is a good choice because its response time is

short and the system is stable when the bicycle is

stationary. Gyroscopic stabilization, where one or more

motorized gimbals tilt the angular momentum of a

spinning rotor. As the rotor tilts, the changing angular

momentum causes a gyroscopic precession torque that

balances the bicycle.

Figure 1 An example of main components of self-

balancing control system.

Advantages of this system are it can produce large

amount of torque, it has no ground reaction forces, and

the system can be stable even when the bicycle is

stationary. Disadvantages are it consumes more energy

and it is physically complex. Research studies using this

concept include Narong et al. [1,5], Jiarui et al. [2], and

Sandeep et al. [4].

Figure 2 Control moment gyroscope (CMG).

4. CONCLUSIONS

In the nutshell, there are several ways in order to

design an efficient self-balancing bicycle which are by

using control moment gyroscope (CMG), mass

balancing, steering control and reaction wheel. Based on

previous research, the usage of CMG is the suitable

choice since it can produce large amount of torque, it has

no ground reaction forces, and the system can be stable

even when the bicycle is stationary. Unfortunately, CMG

consumes more energy and it is physically complex but

this disadvantage will be contained with further research

and development in the future.

REFERENCES

[1] J. He and M. Zhao, “Control system design of self-

balanced bicycles by control moment gyroscope,”

in Proceedings of the 2015 Chinese Intelligent

Automation Conference, pp. 205-214, 2015.

[2] S.K. Gupta and V. Gulhane, “Pose estimation

algorithm implication for bicycle using gyroscope

& accelerometer,” Design approach, vol. 4, 2014.

[3] N. Aphiratsakun and K. Techakittiroj, “Single loop

and double loop balancing control of AU Self-

balancing Bicycle (AUSB),” 2012 IEEE

International Conference on Robotics and

Biomimetics, 2012.

[4] N. Aphiratsakun and K. Techakittiroj,

“Autonomous AU bicycle: Self-balancing and

tracking control (AUSB2),” 2013 IEEE

International Conference on Robotics and

Biomimetics, 2013.

[5] K. Kanjanawanishkul, “LQR and MPC controller

design and comparison for a stationary self-

balancing bicycle robot with a reaction wheel,”

Kybernetika, pp. 173-191, 2015.


__________


Optimizing the design of n-channel trench power MOSFET device using Taguchi method

N.A. Ahmed Nazri, F. Salehuddin*, N.R. Mohamad, M.N.I.A. Aziz, M. Hadinan, A.S.M. Zain,

A.H. Afifah Maheran, A.R. Hanim, H. Hazura, S.K. Idris

Centre for Telecommunication Research and Innovation, Faculty of Electronics and Computer Engineering,

Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia


Keywords: Trench power; Taguchi method

ABSTRACT – In this study, the impact of the process

parameters such as trench width, trench depth, epitaxial

thickness and epitaxial thickness on the response of

breakdown voltage and on-resistance for the n-channel

trench power MOSFET devices were investigated. The

virtual fabrication of the device was performed using

ANTHENA module while the device electrical

characteristics was simulated using ATLAS module.

These two modules were combined with L8 orthogonal

array in Taguchi method to aid design and optimize the

process parameters. In this work, the most significant

factor that affects the threshold voltage, breakdown

voltage and on-resistance was the epitaxial resistivity.

The result shows that the threshold voltage (VTH),

breakdown voltage (BV) and on-resistance (RON) for n-

channel trench power MOSFET devices after an

optimization approach was approximately 1.471V,

34.57V and 0.161mΩ/cm2 respectively.

1. INTRODUCTION

The planar and the trench designs are the two

common designs of power MOSFETs. Out of various

possible options, the trench gate design yields the most

efficient performance as a discrete power device for

relatively low voltage applications compared to any

other structure with similar specifications due to their

lower attainable on-resistance [1]. The trench gate

power MOSFETs has become the mainstream of low

voltage power switch since it has been developed about

20 years ago. In terms of resistance and gate charge, the

trench gate technology has an advantage in contrast with

the doubled diffused MOSFET transistor for the

products with a drain voltage capability less than 100V.

By using this technology, the gate electrodes are buried

inside the trench of the device and the channels are

created along the sidewall of the trench. For the power

device, there is a trade-off between the specific on-

resistance and breakdown voltage. Achieving the lowest

value of on-resistance without breakdown voltage

deterioration is crucial for the power devices [2]. This is

due to the on-resistance of the power MOSFET rise

immediately to the rise in breakdown voltage, causing

high conduction losses, even when using semiconductor

materials that are costly and ultimately lowers the

overall efficiency of the system [3]. The application

nowadays keeps demanding further reduction in on-

resistance with adequately high breakdown voltage even

though the on-resistance proposed by the trench power

MOSFET has been the lowest among diverse possible

structures [1]. To meet this ever continuous demand, the

optimization of the input process parameters that have

an impact on the on-resistance and breakdown voltage

of trench power MOSFET is needed. The optimization

was done to choose a set of variables (parameters)

values subject to the diverse limitations that will

produce the desired optimum response. In this study, the

impact of trench width, trench depth, epitaxial thickness

and epitaxial resistivity on the breakdown voltage and

on-resistance of the power MOSFET device was

investigated.

2. MATERIALS AND METHODS

The completed structure of n-channel trench power

MOSFET device is shown in Figure 1. After the

structure of n-channel trench power MOSFET device

was modeled in ANTHENA simulator, the electrical

characteristics of the structure such as threshold voltage

(VTH), breakdown voltage (BV) and on-resistance (RON)

is simulated using ATLAS simulator.

Figure 1 Cross section of n-channel trench power

MOSFET structure

For a power MOSFET with low (<50V)

breakdown voltages, the VTH within the range of 1 – 2V

is required [3]. According to Korec et.al. [4], a power

MOSFET device with an epitaxial thickness of 4μm,

epitaxial doping concentration of 3.5x1016 atom/cm3 and

gate oxide thickness of 600Å is suitable for obtaining a

breakdown voltage of 30V. Therefore, it is important to

achieve the minimum RON for a power MOSFET

structure that is capable of supporting a breakdown

voltage more than 30V [3]. The results of VTH, BV and

Ron were analyzed and processed to get the optimal

Ahmed Nazri et al., 2017

163

design by using L8(27) of orthogonal array in Taguchi

method. The optimized results obtained was simulated

in order to verify the predicted optimal design. The

values of the process parameter and noise factor at

different levels are listed in Tables 1 and 2 respectively.

Table 1 Process Parameter and their level. Symbol Process parameter Unit Level 1 Level 2

A Trench width µm 1.00 1.05

B Trench depth µm 1.00 1.10

C Epitaxial thickness µm 4.00 4.10 D Epitaxial resistivity cm 0.13 0.18

Table 2 Noise Factors and their level. Symbol Process parameter Unit Level 1 Level 2

Y Epitaxial Implant Temp

°C 1200 1205

Z Gate Oxide Temp °C 880 885


VTH of the device belongs to nominal-the-best

quality characteristics, while BV belongs to larger-the-

best quality characteristics and RON belong to smaller-

the-best quality characteristics. The S/N ratio (SNR) for

VTH is selected to get closer or given target value

(1.5V), which is also known as nominal value. The SNR

(dB) for each level of the process parameters and factor

effects on SNR (%) for VTH, BV and RON is summarized

in Table 3.

Table 3 SNR for VTH, BV and RON in n-channel

trench power MOSFET. Output

Responses

Process

Parameter

SNR (dB) Factor Effect

on SNR (%) Level

1

Level

2

VTH

(Nominal-

the-best)

A 28.20 30.80 0

B 32.83 26.17 15

C 33.24 25.75 19 D 23.35 33.65 23

BV

(Larger-

the-best)

A 30.75 31.43 5

B 30.69 31.48 6

C 30.77 31.41 4 D 30.04 32.14 46

RON

(Smaller-

the-best)

A 72.73 72.54 0

B 71.61 73.67 23 C 72.64 72.63 0

D 74.16 71.12 51

The individual optimum condition for VTH, BV

and RON were compared to choose the best optimization

value for each of the process parameters of n-channel

trench power MOSFET device. The optimal value is

chosen due to the high percentage contribution of S/N

ratio for each process parameter. The full

recommendation for optimization is A1,B2,C1,D1 i.e.

trench width is 1.00μm (level 1), trench depth is 1.10μm

(level 2), epitaxial thickness is 4.00μm (level 1) and

epitaxial resistivity is 0.13Ωcm (level 1). Once the best

setting for a combination of the output response has

been identified, the confirmation test will be performed

to verify the accuracy of the prediction. Table 4 shows

the percentage of performance improvement in VTH, BV

and RON of the device before and after the optimization

is done by using Taguchi method. According to this

table, it was found that the VTH is increased by 3.29%

from 1.424V to 1.471V after optimization. This new

VTH value is within the range of 1 to 2V and is closer to

the nominal value (1.5V). The BV is increased by

47.11% from 23.50V to 34.57 after optimization. This

new value exceeds the targeted breakdown voltage for

the 30V class of trench power MOSFET device.

Meanwhile, the RON is reduced by 39.01% from

0.224mΩ/cm2 to 0.161mΩ/cm2 after optimization. This

new value exceeded the target and is lower than

0.199mΩ/cm2 reported by Su et al. [5].

Table 4 Device performance before and after

optimization. Output

Response

Targeted

Value

Before

Optimize

After

Optimize

%

Different

VTH (V) 1~2 1.424 1.471 3.29%

BV (V) >30 23.50 34.57 47.11%

RON (m/cm2) <0.199 0.224 0.161 39.01%

4. CONCLUSIONS

As a conclusion, to obtain a high BV with the

lowest RON is desirable. To achieve this, the

optimization of the input process parameters that have

an impact on the device performance was necessary.

Through this study, the factors that most affect the

output response of n-channel trench power MOSFET

device has been identified and the optimum factor levels

were also determined. Epitaxial resistivity was found as

the most significant factor that affects the VTH, BV and

RON of n-channel trench power MOSFET device. The

second most significant factor was the trench depth. At a

gate bias of 10V, the VTH, BV and RON for n-channel

trench power MOSFET device after optimization

approaches are about 1.471V, 34.57V and 0.161mΩ/cm2

respectively. These values have reached the target.

ACKNOWLEDGEMENT

The authors would like to thank the Ministry of

Higher Education (MOHE) and UTeM for sponsoring

this study under the research grant

(RAGS/1/2014/TK03/FKEKK/B00064).

REFERENCES

[1] S.S. Raghavendra and M.K. Jagadesh, “Trench

gate power MOSFET: Recent advances and

innovations,” Advance in Microelectronics and

Photonics, pp. 1-23, 2012.

[2] Y. Lei and B. Zhang, “A lateral power MOSFET

with the extended trench gate in substrate,” in

International Conf. Solid-State and Integrated

Circuit Technology, pp. 908-910, 2010.

[3] B.J. Baliga, “Advanced power MOSFET

concepts,” Springer Science, LLC, 2010.

[4] J. Korec, N.D. Mohamed and D.C. Pitzer, “Method

of fabricating trench-gated power MOSFET,” U.S.

Patent US6534366B2, March 2003.

[5] X. Su and Q. Feng, “Investigation of performance

optimized power Trench MOSFETs with double

epilayer,” in International Conf. on Advanced

Power System Automation and Protection, pp.

2166-2169, 2011.

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