Thesis submitted in accordance with the requirements of the Universiti Teknikal

Malaysia Melaka for the Bachelor Degree of Manufacturing Engineering

(Robotics and Automation) with Honours

By

Amirul Bin Sait

Faculty of Manufacturing Engineering

May 2008

Potential Application of Ferrofluid for

Robot Gripping Mechanism

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

UTeM Library (Pind.1/2007)

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

BORANG PENGESAHAN STATUS LAPORAN PSM

JUDUL:

POTENTIAL APPLICATION OF FERROFLUID FOR ROBOT GRIPPING MECHANISM

SESI PENGAJIAN: Semester 2 2007/2008

Saya Amirul Bin Sait

mengaku membenarkan laporan PSM / tesis (Sarjana/Doktor Falsafah) ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:

1. Laporan PSM / tesis adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis.

2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan untuk tujuan pengajian sahaja dengan izin penulis.

3. Perpustakaan dibenarkan membuat salinan laporan PSM / tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi.

4. *Sila tandakan (√)

SULIT

TERHAD

TIDAK TERHAD

(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia yang termaktub di dalam AKTA RAHSIA

RASMI 1972)

(Mengandungi maklumat TERHAD yang telah ditentukan oleh

organisasi/badan di mana penyelidikan dijalankan)

(TANDATANGAN PENULIS) Alamat Tetap:

NO 53 TMN PUTERI, LRG CAHYA INDAH 1, JLN SULTAN TGH, 93050,

PETRA JAYA, SARAWAK.

Tarikh: _______________________

(TANDATANGAN PENYELIA)

Cop Rasmi:

Tarikh: _______________________

* Jika laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak organisasi berkenaan

dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD.

APPROVAL

This report is submitted to the Faculty of Manufacturing Engineering of UTeM as a

partial fulfillment of the requirements for the degree of Bachelor of Manufacturing

Engineering (Robotics and Automation) with Honours. The members of the

supervisory committee are as follow:

Muhamad Arfauz Bin A. Rahman

(PSM Supervisor)

"Insert the date and official stamp here"

DECLARATION

I hereby declare that this report entitled “Potential application of Ferrofluid for

Robot Gripping Mechanism” is the result of my own research except as cited in the

references.

Signature :

Author’s Name : AMIRUL BIN SAIT

Date : May 7, 2008

i

ABSTRACT

Ferrofluids are magnetically controllable fluids where it can be used in positioning

system as an active medium. With an applied external magnetic field, the capability of

the ferrofluid is the main properties for the research. In this study, ferrofluid are used to

develop a potential application in gripping mechanism. The properties and the influences

of the ferrofluid in positioning are gathered and the research start with identify the title

main element which is ferrofluid and the robot gripping mechanism. Through the

literature review, the mechanisms are developed and the development of the robot

gripping mechanism presented in order to come out with a replica. The methodology

consist the method used and explanation related to the robot gripping mechanism

development. Furthermore, the conceptual design presented for design development and

the selection is according to the Pugh screening concept. Then, detail design through the

simulation, replication and analysis process. The simulation output shows how the

mechanism works and gives better understanding about the ferrofluid movement.

Analysis on the force and the moment for the finger and shaft presented according to free

body diagram from the replication. In this case the spring constant or force constant of

the spring determined in order to know the suitable spring force. In addition, the viscosity

of the ferrofluid discussed as it reflect proportionally to the current.

ii

ABSTRAK

Ferrofluid adalah cecair magnet yang dapat dimanipulasikan dengan kehadiran suatu

medan magnetik. Dalam kajian ini, cecair magnet digunakan sebagai satu medium

penggerak yang berpotensi dalam mekanisma cengkaman pada robot. Ia dimulakan

dengan menghuraikan isi-isi yang terdapat di dalam tajuk yang melibatkan cecair magnet

dan mekanisma cengkaman robot. Pengumpulan maklumat dilakukan melalui rujukan

jurnal-jurnal, melayari internet serta buku dan setiap maklumat yang berkaitan sahaja

yang diambil. Seterusnya, kaedah-kaedah yang akan digunapakai digariskan dengan

menerangkan proses-proses yang terlibat dalam menghasilkan simulasi dan replika. Oleh

itu, lakaran mekanisma secara dua dimensi dihasilkan untuk setiap idea yang tercetus dan

semua lakaran tersebut akan dipilih menggunakan kaedah matrik Pugh, di mana

rekabentuk yang mendapat markah tertinggi akan dipilih. Berdasarkan rekabentuk

tersebut, lukisan tiga dimensi, simulasi dan replika pula dihasilkan untuk memberi

gambaran yang lebih jelas berkenaan rekabentuk dan mekanisma pergerakan cecair

magnet. Akhir sekali, analisis dibuat ke atas mekanisma tersebut terhadap daya dan

momen yang dihasilkan serta pekali spring dan kelikatan cecair magnet untuk

mendapatkan kesesuaian daya yang diperlukan oleh cecair magnet untuk menggerakkan

aktor.

iii

DEDICATION

For My parents.

iv

ACKNOWLEDGEMENTS

First and foremost, i thanks the almighty god for being my side throughout. I wish to

extend my sincere thanks Mr. Muhamad Arfauz b. A Rahman as my supervisor for

helping and always guiding me throughout the development of the research. I would like

to thank to Mr. Lau Kok Tee, Mr. Ubaidillah, Mr Ahmad Yusairi b. Bani Hashim, Mr

Khairol Anuar b. Rakiman, Mr. Shariman b. Abdullah and Mrs. Silah Hayati bt Kamsani

for providing me with outstanding information to conduct my learning process and

research development. I am grateful to thank my colleagues Mr. Mohd. Azwan b

Mohammad and Mr. Zamri b. Ahmad, as many creative thoughts and valuable discussion

about the research have had a significant influence throughout my project development.

Also not to forget the Faculty of Manufacturing Engineering, Universiti Teknikal

Malaysia Melaka management for allowing me to be a part of the network and thus

giving me a chance to gain useful knowledge and experiences. In addition, i am specially

indebted to Miss Maszilzi Hazeelia bt Mutaza and my parents, Mr Sait Rutu and Mrs

Hatabah Alli for their love, encouragement and support me throughout the development

of this research.

ix

LIST OF FIGURES

2.1 Bar magnet showing line of force between the poles (Myke

predko, 2003).

8

2.2 Rolling bearings with integrated magnetic fluid seals (W.

Ochonski, 2005).

9

2.3 Figure 2.3 : Repulsion of like poles ((Richard J. Fowler, 2003). 10

2.4 Magnetic fields generated by a coil carrying a current (Myke

Predko, 2003).

11

2.5 Example diagram of electromagnet cross-section (Myke Predko,

2003).

12

2.6 Simple application of electromagnet in operation (Myke Predko,

2003).

12

2.7 Composition of magnetic fluids (E. Uhlmann , 2006). 13

2.8 Rolling bearings with integrated magnetic fluid seals (W.

Ochonski, 2005).

15

2.9 (a) Magnetic field vs. the distance to the magnet magnet (R. Pérez-

Castillejos et al, 1999).

17

2.9 (b) Mechanical pressure vs. the distance to the magnet (R. Pérez-

Castillejos et al, 1999).

18

2.10 Experimental and theoretically obtained output voltage of the

pressure sensor

18

2.11 Vacuum-rotary feedthrough (W.Ochonski, 2005). 20

2.12 D'Adrsonval galvonometer with ferrofluid (K. Raj et al, 1995). 21

2.13 Tilt sensor utilizing ferrofluid as variable induction core (K. Raj

et al, 1995).

23

2.14 An unusual loudspeaker with dual magnetic gaps and a fiat voice

coil (K. Raj et al, 1995).

23

2.15 Construction of a thick film ferrofluid cell (Luis Martinez et al, 24

x

2005).

2.16 Optical system for estimation of Verdet constant (Luis Martinez

et al, 2005).

25

2.17 Ferrofluid fixed with a permanent magnet. 26

2.18 Principle and experimental set-up of a one-axis system with

scattered (I) and optimized magnetic field (II) (E. Uhlmann & N.

Bayat, 2004)

27

2.19 Load capacity of the one-axis positioning system for different

ferrofluids and volume of fluid.

28

2.20 Principle and prototype of a miniaturized multidimensional one-

axis positioning system.

28

2.21 Actor cases (at the top) and experimental set-up of multi-axis

positioning systems (below at the right) (E. Uhlmann & N.

Bayat, 2004).

29

3.1 (a) Flow Chart of the robot gripping mechanism process 32

3.1 (b) Flow Chart of the robot gripping mechanism process 33

3.2 The step of concept generation method. 34

3.3 Overall “black box”. 36

3.4 Refinement showing subfunctions 37

3.5 Flow chart for the replication of the robot gripper 42

3.6 Influences on the load capacity of the magnetofluidic

positioning system (E. Uhlmann & N. Bayat, 2003)

43

3.7 Influences of the coil current to the actor (E. Uhlmann & N.

Bayat, 2003).

45

4.1 Conceptual design 1 47

4.2 Conceptual design 2 48

4.3 Conceptual design 3 49

4.4 Conceptual design 4 50

4.5 3 Dimensional drawing using Solidworks software 52

4.6 Polygon Cube tool 53

4.7 Channels Object 53

xi

4.8 Wireframe of the robot gripper 54

4.9 Shaded modeling diagram 54

4.10 Animation keyframe 55

4.11 Initial position of the designed robot gripper 56

4.12 Gripping position of the robot gripper 57

4.13 Final simulation of the robot gripper 57

4.14 The replication of the robot gripper 60

5.1 The replication cross-sectional diagram 61

5.2 The load versus spring displacement graph. 64

5.3 Load characteristic with the Cobalt Based Ferrofluid (E.

Uhlmann & N. Bayat, 2003)

66

5.4 Connection of the circuit 67

5.5 Electric circuit diagram for the robot gripper mechanism 67

6.1 Friction produce when the actor moves up and down 70

xii

LIST OF TABLES

2.1 Gripper classification according to their physical principle of

operation (Gareth J. Monkman et al, 2007)

7

2.2 Gripper classification and suitability of object materials (Gareth J.

Monkman et al, 2007)

7

2.3 Carriers in the commercial ferrofluid (K. Raj et al, 1995)

16

2.4 Thermal stabilities of successive generations of ferrofluids. Equal

amounts of ferrofluids are exposed to 175°C in dishes until the

fluids congeal. The number of hours represent the relative thermal

stability (K. Raj et al, 1995)

16

2.5 Properties of a thick film ferrofluid cell (Luis Martinez et al, 2005) 25

4.1 The screening matrix for the conceptual design of the robot gripping

mechanism

51

4.2 The manufacturing process involve 58

5.1 Spring displacement when the load applied 63

xiii

LIST OF ABBREVIATIONS, SYMBOLS, SPECIALIZED

NOMENCLATURE

nm - nanometer

µm - micronmeter

2D - Two Dimensional

CAD - Computer Aided Manufacturing

3D - Three Dimensional

1

CHAPTER 1

INTRODUCTION

1.1 INTRODUCTION

Materials that are attracted by magnetic fields are called magnetic materials (Robert J.

Fowler, 2003). The most common magnetic materials are iron, iron compound and alloys

containing iron or steel (Robert J. Fowler, 2003). These magnetic materials are also

called ferro magnetic materials as ferro is a prefix that means iron. In general, ferrofluid

is magnetic iron in liquid form. Electricity and magnetism cannot be separated as

magnetism created by an electric current. It is known that an electric current produces a

magnetic field (Robert J. Fowler, 2003). The main application areas which is sealing,

damping and heat transfer, continue to dominate the commercial activities but in each

category new market opportunities have resulted in the development of mechanical

devices and ferrofluids. There is now an increased use of ferrofluids in stepper motors,

and D'Arsonval meters are at the stage of testing. In both cases one of the objectives is to

damp the system and improve product performance. Transducer have become more

importance of the magnetic fluids and, as a result, new sensor products are now in the

manufacturing field.

There has been development in the synthesis of the magnetism and magnetic materials

due to the potential of various applications. As one of the magnetic material, ferrofluid

has been used for biomedical applications and technical applications. In biomedical

applications, it is because by their low toxicity and high magnetizations value for

diagnostics and treatment of tumor cells such as magnetic resonance tomography (MRT),

2

magnetic drug targeting (MDT), magnetic hyperthermia (MHT) and artificial heart and

muscles (Uhlmann, 2006). Biomedical applications focus on the single colloids’

properties. While in technical applications there are more on product and process

application likes loud speaker, lubricants, and seals in feed-through, cooling, sensors and

damping medium (E. Uhlmann, 2006). Technical applications consider the ferrofluids’

properties as a whole fluid described by its magnetorheological behavior, magnetization

and permeability for magnetic forces. In positioning applications, it still less applies.

Magnetic fluid also called ferrofluid (W. Ochonski, 2005), consist magnetic particles that

able to react with magnetic field. Ferro fluids respond immediately to changes in applied

magnetic field and removing the field quickly randomize the moment (W. Ochonski,

2005). It explains that the ferrofluid is compliance and we can manipulate it according to

the wanted current. The magnetic field can be controlled as known magnetic field move

from north to the south. In order to develop the robot gripper, it requires movement and

force. Here, ferrofluid will be used as an active medium for generating a variable

magnetic force which will acts on actor and enables the movement (E. Uhlmann & N.

Bayat, 2004). The magnetic force will be produced from the movement of the ferrofluid

that can be control by the current through the coil installed. Using a permanent magnet

also can produce a magnetic field, however, coil is better as the concentration of the

magnetic field can be manipulate. As a result, it will transmit the force to the actor of the

robot gripper.

There is high potential of ferrofluid applying the robot gripping mechanism as the

ferrofluid inside can be apply to other application, for example, sensoring mechanism.

Also, precise movement can be adjusted through the current applied to the coil.

Furthermore, it is a new technological application of the positioning system instead of

hydraulic, pneumatic and electrical system.

3

1.2 PROBLEM STATEMENT

Using electrical supply is one of the common for developing a robot gripper. However,

the danger of electrical sparks, non-direct drive motors are geared down and can cause

such problems as backlash, friction, compliance and wear which can affect the accuracy

and repeatability of the robot (James W. Masterson et al, 1996).Hydraulics can supply

large amount of instant power and provide precise motion over a wide range of speeds

but it is expensive to purchase and maintain. It is not energy efficient and noisier than

electrical units and due to fluid leaks, they are not recommended for clean room

environments (James W. Masterson et al, 1996).Pneumatics works at high speeds and is

economical to operate and maintain. The disadvantage is air is compressible, making

precise placement and positioning more difficult to control. It is difficult to keep air used

by pneumatic system clean and dry and noisier than either electrical or hydraulic systems

(James W. Masterson et al, 1996). With the use of the ferrofluid, this new technological

application can reduce the noise, as the ferrofluid is reflect only with generated coil.

Besides, the large amount of power can be produce and provide precise motion.

1.3 OBJECTIVE

To analyze and evaluate the potential application of ferrofluid in robot gripping

mechanism.

To design and develop a replication of a suitable robot gripping mechanism.

1.4 SCOPE

To collect, analyze and evaluate the relevant information regarding to the

ferrofluid application from previous and current research.

To design, simulate using Autodesk Maya 8.0 and analyze the robot gripper.

To develop a replication of robot gripper.

4

1.5 BENEFIT

The study on the ferrofluid in robot gripping mechanism will be a new application of

robot gripper instead of using motor, pneumatic and hydraulic. The ferrofluid will be an

active medium to replace the conventional mechanism and it can be exploit for another

usage for example, a sensor as ferrofluid is now widely use. Furthermore, it can reduce

noise, as we know present mechanism that using motor, pneumatic and hydraulic produce

noise. The compliance criteria of the ferrofluid can be manipulate and the relative high

range of positioning with an accuracy of only a few micrometer. In addition, it also can

be use for a safeguard against overload.

5

CHAPTER 2

LITERATURE REVIEW

2.1 ROBOT GRIPPER

Gripper is considered as a subsystem of a handling mechanism which provides temporary

contact with the object to be grasped (Gareth J. Monkman et al, 2007). From the

definition, we can understand that operation of the gripper is grasping an object.

However, the term “gripper” is also used in cases where no actual grasping, but rather

holding an object, for example in vacuum suction where the force can act on a material.

There are many gripper can be found in industry and their functions is depend on the

specific application. According to the Gareth J. Monkman et al, their function can be as

following ;

(a) Temporary maintenance of a definite position and orientation of the workpiece

relative to the gripper and handling equipment.

(b) Retaining of static (weight), dynamic (motion, acceleration or deceleration) or

process specific force and moments.

(c) Determination and change of position and orientation of the object relative to the

handling equipment by means of wrist axes.

(d) Specific technical operations performed with, or in conjunction with the gripper.

In other word, the main function of a gripper is to grasp and to release workpieces during

the material transfer route (Fan Yu. Chen, 1982). In general, the gripper is a specialized

device that can do specific task or job used to handle one or few objects in a repetitive

operation which required calculated force and versatility.

6

2.2 ROBOT GRIPPER CLASSIFICATION

One should differentiate between grasping (prehension) and holding (retention) forces.

This is important as these are the most used type of gripper in industry. The grasping

force is applied at the initial point of prehension (during the grasping process), while the

holding force maintains the grip thereafter (until object release) (Gareth J. Monkman et

al, 2007). In general, the retention force may be weaker than the prehension force. This is

because the grasping force is determined by the energy required from the mechanical

motion. Robot grippers may be categorized in broadest manner. Fan Yu Chen (1982)

classified gripper into three types which is mechanical finger, vacuum and magnetic, and

universal grippers.

The mechanical finger type is widely used in industry where a direct mechanical force

according to the number of fingers in gripper. The majority of grippers are of the 2-finger

type and 3-finger type of grippers. For vacuum and magnetic type, includes those fitted

with suction cups or electromagnets as force-exerting elements. In other hand, universal

gripper consists of inflatable fingers, soft fingers, 3-fingered grippers and grippers that

are made of mouldable materials (Fan Yu Chen, 1982). The classification by Fan Yu

Chen is based on the function years before 1982. As more new type of gripper has been

develop nowadays, Gareth J. Monkman et al (2007) has classified it more specific based

on the functions, physical of operation and suitability. There are four main groups that

been categorized by Gareth J. Monkman et al (2007) which is : Impactive (a direct

mechanical force from two or mode directions is applied to the object), Ingressive (

prehension of the object is achieved through permeation of the object surface), Astritive

(a binding force is applied in a single direction) and Contigutive (non impactive methods

whereby a direct contact is required to provide a prehension force in a single direction).

These four categories are listed in the table 2.1 and 2.2 below.

7

Table 2.1 : Gripper classification according to their physical principle of operation

(Gareth J. Monkman et al, 2007)

Prehension method Gripper type Typical object materials

Impactive Rigid objects

Ingresive Intrusive Flexible Objects : textiles, carbon and glass fibre

Non-intrusive Flexible Objects : textiles, carbon and glass fibre

Vacuum suction Non-porous, rigid materials

Astrictive Magnetoadhesion Ferrous materials

Electroadhesion Light sheet materials and microcomponents

Thermal Flexible Objects : textiles, carbon and glass fibre

Contigutive Chemical Carbon fibre with glue impregnation

Fluid Small, light objects (microcomponents)

Table 2.2 : Gripper classification and suitability of object materials (Gareth J. Monkman

et al, 2007)

Prehension method Gripper type Typical examples

Impactive Clamps (external fingers, internal fingers, chucks,

spring clamps), tongs (parallel, shear, angle, radial)

Ingresive Intrusive Pins, needles, hackles

Non-intrusive Hook and loop

Vacuum suction Vacuum suction cup/ bellows

Astrictive Magnetoadhesion Permanent magnet, electromagnet

Electroadhesion Electrostatic field

Thermal Freezing, melting

Contigutive Chemical Permatack adhesives

Fluid Capillary action, surface tension