my new kinematics and aircraft assembly robotics studies 28th august 2016

Mr. Geoffrey Allen Wardle. MSc. MSc. Robot Kinematics Study in support of the prime FATA Wing Design 2012-2017

MY KINEMATICS AND AIRCRAFT ASSEMBLY ROBOTICS STUDIES.

By Mr. GEOFFREY ALLEN WARDLE. MSc. MSc. C.Eng. Snr MAIAA 2015 to Date.


Faced with ballooning order backlogs for airframes, and an ever increasing demand for a shorter

development and build cycle times for future aircraft as well as current models, aerospace

manufactures and automation system suppliers are exploring new ways to automate a broader

range of aircraft manufacturing processes beyond drilling and filling. The objective of this study is to

build on the Catia V5.R20 kinematic design work of Workbook 3 which was centered on modeling

the actuation of control surfaces, by applying the modeling techniques developed in the Kinematics

studies to the design of assembly robots, assembly fixtures, and the human builder to study the

automated assembly of airframe wings in support of my private Future Advanced Technology

Aircraft study. These robot designs will be used to asses: - assembly clearances, space envelopes

with human interactions, fixtures, and individual part features required for structural assembly and

systems installation using the FATA outboard wing section as an example structure.

Within the limits of Catia V5.R20 Kinematic modeling (which include the inability to combine the

simulation of sub-mechanisms in to a single larger mechanism, which means that the entire robot

mechanism will have to be modeled as a single large mechanism), to model full sized ABB

IRB4400, and ABB IRB6650S robots from datasheet and surface model dimensions, simulating

their functional space envelopes in combination with the human builder in assembly activities

required for the baseline and developed wings of the FATA aircraft project. Path simulations and

tracker simulations will be undertaken to ensure that line of sight is preserved between the robots

optical sensors and a simulated Leica laser tracker (modeled from catalogue data, see section 3 of

this presentation ). Studies will also address the behaviour of the robots under load conditions to

determine deflections using GSA, leading to placement errors. This work is focused on establishing

a Type-1 feature based assembly methodology for the FATA wing project.

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OBJECTIVES OF THIS PRIVATE STUDY IN SUPPORT OF FATA.


Contents of this presentation in support of my FATA wing design study.

*Cover illustration: - My ABB Robots and Human Builder for size comparison for this study before simulation and

analysis.

Section 1:- Overview of robotic assembly in the development of the baseline wing.

Section 2:- Kinematic modeling of robotic devices and the Human Builder (In Work).

Section 3:- Advanced assembly technology relevant to the FATA Baseline Wing.

Section 4:- Development of tooling and infrastructure to support automated assembly of the

FATA Baseline wing (In Work).

Section 5:- Automated assembly of the FATA Baseline Outboard Wing Section (In Work).

3


As part of the core study of the FATA wing design development project consideration is given to

automated assembly by robots, designing clearance for robotic assembly and part handling, end

effector grips pressures etc. As well as trades of vertical assembly with ease of systems installation

(both sides) verses horizontal assembly from pre prepared build modules. The required

modifications to parts to facilitate automated assembly and their effects on the part design and

stressing will be a major part of this study. Analysis will also include tool space envelopes derived

from catalogue data as per my assembly studies for the Mantis UAS, to determine the ease of

assembly, employing Catia V5 Kinematics for robot approach and manipulation envelopes. Robots

have an arm that functions as a human arm: i.e. the arm can pick up objects with great precision

and repeatability. A robot arm is able to move in at least three directions: in and out: up and down:

and around and when a robot hand or end effector is added, another three axis of motion are yaw:

pitch: and roll as shown in figures 1 and 2.

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Section 1:- Overview of robotic assembly in the development of the Baseline wing.

Fig 1:- Robot movement capability. Fig 2:- Robot assembly capability in a fuselage.


Robots by functions, fall into four basic categories:-

1) Pick and Place (PNP) this is the simplest of robots and its function is to pick up a part and move

it to another location. Typical applications include machine loading and unloading and general

materials handling tasks such as the GKN Aerospace automated disposition of composite material:

2) Point to Point (PTP) some which are similar to PNP robots, in that they move material from one

location to another, hence point to point, however it can move to literally hundreds of points in

sequence. At each point sophisticated PTP robots can stop and perform an action such as spot

welding, gluing, drilling, deburring, or a similar task:

3) Continuous path (CP) robot also moves from point to point but the path it takes is critical. This is

because it performs its task while it is moving. Paint spraying, seam welding, cutting and inspection

are typical applications of this type:

4) Robotic assembly (RA) shown in figures 1, 2 and 3 are the most sophisticated robot types of all

and combines the path control of CP robots with the precision of machine tools. RA often work

faster than PNP and perform smaller, smoother and more intricate motions than CP robots. The

flexible hybrid robots shown in figure 3 use a fully segmented arm to hold the end effector driven by

a series of individual drive rods and actuators, producing a snake arm which can access confined

spaces such as a wing torsion box to install fasteners for example. 5

Robotic assembly in the development of the Baseline wing (continued).


The application of robots to the aircraft assembly has been limited to drilling and filling due to

deficiencies in positional accuracy. The majority of airframe applications require tolerances in the

order of +/- 0.25mm or less which have in the past been well beyond the capabilities of

conventional industrial robots used in the automotive industry. However with the ever increasing

computing power available in last decade, which has enabled secondary feedback, high-order

kinematic modeling, and fully integrated conventional CNC control computing, the new breed of

industrial robots can now compete on a performance level with customized high precision motion

platforms. As a result, the articulated arm can be applied to a much broader range of assembly

applications that were once limited to custom machines, including one-up assembly, two sided

drilling and fastening, material removal, automated stitching, and automated fiber placement.

The accuracy with which features are placed by automated systems are a function of two main

criteria:- (1) the positional accuracy of the motion platform in free space: (2) the ability of the motion

platform to remain on path or in position when loads are applied. For example in a drilling operation

the drilling robot needs to position itself at the preprogrammed hole location and remain stationary

when pressure foot and drill thrust forces are applied, and for path-controlled applications such as

part location, trimming, or fibre placement, the robot must be dynamically stable, and remain on its

programmed path resisting forces induced by cutting or compaction, or taking up of component

weight. Methods of maintaining feature placement accuracy using these autonomous systems as

well as assembly feature design will be major parts of this study, based on simulation research and

published works.

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The assembly tolerance requirements for airframe structures has lead automation equipment

suppliers to design custom dedicated equipment to meet these tolerance requirements, however

these custom machines are expensive and have usually been focused on a single application,

which makes them difficult to justify for relatively short production runs found in the aerospace

industry. The application of articulated arm robots in aerospace has been developing for many

years now, with varying degrees of success as discussed in section 3, and these studies have been

based on experience within the automotive industry. These types of robots offer airframe

manufactures cost and application flexibility benefits, in so much as their mass is relatively low, and

their foundation requirements are minimal so this type can usually be installed on an existing

factory floors, and the articulated arm can span a large working envelope and is capable of

navigating along highly curved surfaces and into tight spaces (ref.1), as illustrated in figures 2,3, 4

and 5(a). Also because the articulated arm robots are produced in high volume for the automotive

industry their cost is significantly lower than a customized positioners. As of 2010 significant

mechanical and control improvements had made robots a viable option in the role of mid-range

assemblers where tolerances are in the order of +/- 0.75mm, but now this has improved position

repeatability to 0.19mm for the ABB IBR 4400/60 which also has a path repeatability of 0.56mm at

an operation speed of 1.6m, and can carry a payload of 60kg with an arm extension of 1.96m.

Manufactures commonly devote 1/3rd of the overall assembly tolerance to automation systems,

and in most cases the tolerance is less than +/-0.75mm requiring the automation system to have an

accuracy of +/-0.25mm or better.

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Figure 3(a):- Application of flexible hybrid robots to airframe assembly .

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driving gears


Figure 3(b):- Flexible hybrid robot applied to

wing stringer installation and inspection.

Figure 3(c):- Articulated arm robots applied to in service upgrades

the tight build tolerances of a LO platform.

Figure 3(b)/(c):- Application of hybrid and articulated arm robots to airframe assembly.

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10

Figure 4(a):- Application of robotics to stitched composite components sewing solutions.

Figure 4(a):- Robot moving the part an example being the manufacture of Boeing 787 Main landing gear braces

(reference 8).


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Figure 4(b):- Application of robotics to stitched composite components sewing solutions.

Figure 4(b): - Robot driving the sewing machine an example of this being the Airbus 380 pressure bulkhead

(reference 8).


Existing technologies are available to improve global accuracy to the levels required by the

aerospace industry, which include: - Real-time guidance via metrology (laser tracker, indoor Global

Positioning System (GPS), or camera systems): directly teaching positions: etc. However design

changes and variations as well as the repositioning of assemblies within automation cells tends to

obviate the use directly teaching positions as a method of improving accuracy, as the aerospace

industry often requires an off-line system for reprogramming the robot as changes to the design or

assembly location occur. Guiding robots in real-time using metrology has been demonstrated to

greatly improve their positional accuracy as described in section 3 (references;-1, 2, and 9).

However the metrology system must include sensitive and relatively expensive equipment. External

systems tend to restrict the working range of the automated system and can have line of site

issues. In some cases when global accuracy in the order of 0.15mm or below is required the use of

an external system or using metrology cannot be avoided, however it is desirable to have an

inherently accurate stand alone automation system where practical in order to reduce system

complexity and cost.

A example of the strides made in integrating robotic systems into airframe assembly is the new

robotic production pulse production line developed by KUKA Systems North America (Sterling

Heights, Ml and Augsburg Germany), for the Boeing 777x which aims to fully integrate robotic

systems into airframe production to reduce cost and increase the production rate of both the new

Boeing 777-8 /-9 and also the current 777 models in production. In September 2014 KUKA

Systems unveiled the new robotic riveting system for the Boeing 777 for the forward and aft

fuselage sections, called the Fuselage Automated Upright Build (FAUB) shown in figure 5(a), which

will be the baseline manufacturing process for all 777 models. 12



This pulse line uses KUKA robots with special end effectors developed by a KUKA company Alema

Automation, for performing riveting operations currently done by hand, at full capacity the FAUB line

will be able to install up to 60,000 fasteners in 777 fuselage sections. This application is directed at

specific high volume processes namely drilling and fastening, which are very high in current

airframe manufacture and can be automated to reduce cost and improve quality through

consistency, and error elimination. The FAUB system is one of KUKA Systems largest ventures in

the Aerospace sector, and was preassembled and tested at their Sterling Heights headquarters,

prior to installation at Boeing‟s facility at Anacortes WA state. Although the end effectors used in

this project have been standard Multi-Function systems used on most KUKA Systems drilling and

fastening systems, the unique aspect has been the adoption of a „Galling Gun‟ service module,

which allows the installation of multiple modules in the end effector to perform different

manufacturing tasks, whilst maintaining clamp up pressure on the airframe structure. Currently

some of the most common modules employed are: - Drilling; Vision; Quality; Insertion; Fastener;

and Sealant. Multiple Metrology systems are used in the FAUB system developed by another

KUKA partner company Variations Reduction Solutions Inc (VRSI of Plymouth MI) which supplies

the vision and laser trackers (see also section 3), and these facilitate the alignment of the

equipment; global positioning of the robots; and local registering of the robots to the product. This

metrology system enables very accurate hole placement to a true positional diameter of 0.1778mm.

In fact drilling and fastening no longer rank as the major problem for aerospace companies

apparently, although solutions in this area are currently still the most requested as they represent

the highest volume activity in aircraft manufacturing of this generation of airframes. Going forward

fay and fillet sealing are possibly the next issues to be addressed by automation robotic systems.

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Front Side

Deviation

Back Side

Deviation

Figure 5(a): - The Fuselage Automated Upright Build (FAUB)

robotic system by KUKA Systems automates most riveting for

future Boeing 777 aircraft, installing 60,000 fasteners per

fuselage with high accuracy.

Figure 5(b): - Duel sided alignment fitting a collar

on a bolt.


As described above the accuracy with which features are placed by automated systems are a

function of two main criteria:- (1) the positional accuracy of the motion platform in free space: (2)

the ability of the motion platform to remain on path or in position when loads are applied, and

although a COTS robot system can perform the manipulation of process tooling, it will generally fail

to meet the positional accuracy and rigidity requirements for the majority of airframe assembly

tasks. With the duel-sided process of bolt and collar installation (as used for the FATA wing rib

installation), the problem is compounded as both systems have to align well enough to reliably feed

the bolt through the parts to be joined, and install the collar on the bolt. The error in alignment

between the heads can be as large as the sum of the accuracies of the two systems shown in

figure 5(b). The tool centre point TCP position is obtained by driving the robot axis to angular

positions based on the kinematics of the robot arm. For example on a typical 3m robot arm, the

standard kinematic model yields an accuracy of approximately +/- 2mm to 4mm within the arms

working volume. But because physical real world robots tend not to exactly match a nominal model

due to manufacturing and assembly variations a unique kinematic parameter set can be developed

to better describe individual arms. This unique model can include higher-order parameters that

describe the effects on TCP position altered by the masses of the robot links, and attached

payloads, as well as non-linear axis behaviour. From reference 1 these models can provide

positional accuracies of nearly +/-0.05mm in a restricted range using a standard COTS robot

system.

With any kinematic model the output motion and positioning of the system is a function of all of the

dynamics data incorporated in the model and therefore can only be as accurate as the input data

and working assumptions.

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Therefore any errors in joint angle are feed through the kinematic model and result in errors in the

TCP position produced by the model. On a typical COTS robot the position feedback for each axis

is located at the servo motor, but ahead of the feedback are numerous sources of error such as

backlash, wind up, and scaling which need to be accounted for in the kinematic modelling of the

system. Although the uni-directional positional repeatability errors of COTS robots are generally

acceptably small, omni-directional positional repeatability errors are more substantial, and testing

(ref (1)) of omni-directional positional repeatability using a 3m arm in typical operational volumes

has demonstrated errors of up to 0.5mm in magnitude. This poor repeatability can be attributed to

uncertainty of the joint position, and because the systems accuracy can only be as good as its

repeatability in 2010 the best a COTS robot system could ever achieve in ideal conditions was

0.5mm. Therefore knowing the exact position of each of the robot axes is fundamental to systems

accuracy. The accurate location of the axis feedback on COTS robots also limits their stiffness as a

mechanical unit because the axial position is held at its input, compliance and backlash are not

accounted for, resulting in poor joint stiffness leading to significant TCP position deflection when

loads are applied. Joint deflection is the result of both link masses and externally applied process

forces, and if not compensated for droop from link masses and payload can exceed 3mm or more

at the TCP position, also forces of less than 200kgf applied at the TCP position e.g. in drilling or

cutting processes can result in a positional deflection of 2mm, most coming directly from the joints.

In order to maintain adequate control of an axis, machine tool designers commonly use secondary

position encoders, mounted at the output of the axis rather than the input, and these sensors are

typically high resolution yielding high repeatability with minimal measurable hysteresis.

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Transferring this technology into articulated robots yields much tighter control of axis position,

higher omni-directional positional repeatability reducing errors to near zero (validated by laser

tracker during combined movement of all axes, which would be the real world operating case), and

also enable the robot system to be calibrated to a higher degree. Validation demonstrations have

shown (ref (1)) a maximum omni-directional position deviation of 0.05mm over 3m which represents

a ten times improvement over non-enhanced robot systems. Additionally removing the slack in the

robot joints of eliminating compliance and backlash factors, enabling more descriptive parameters

to be employed (which would previously have been more difficult to accurately solve for) when

tailoring the enhanced kinematic chain. Hence with the repeatability in check from the sensors at

the axis outputs a more representative kinematic model can be produced, and to do this requires

an accurate metrology system evaluation using for example laser trackers. To conduct an

evaluation the end effector could be fitted with at least three metrology targets:- one in the tool

point, and the other two on the rigid portion of the end effector, the robot can then be programmed

to a set of unique random poses within the normal working range of the system, at each pose

location position data for each of the targets along the axis positions would be captured and used to

solve for the kinematic parameters using common regression techniques, with data not used in

calibration, collected at additional poses within the working volume to validate the systems

accuracy.

The next stage in achieving accuracy on the work piece is to evaluate the positional deflection

under external loadings which are introduced in a number of ways, during assembly operations, for

example, when drilling and fastening single or dual-sided, clamping forces are used to stabilise the

process. 17



Other external load examples are: - the cutting loads induced in trimming and milling operations:

compaction loads in fibre placement to properly adhere the material to the mould: etc. Because the

articulated arm lacks stiffness, deflection occurs under these external loads mostly at the joints, and

testing (ref (1)) have demonstrated that 50% to 80% of the total TCP position deviation can be

attributed to these loads in COTS robot systems. With the adoption of secondary encoders on

each axis, as described above the local joint error is reduced to negligible values, although external

load still cause deflection in the links, bearings, base mounting plate, etc. Therefore a platform with

high stiffness is most desirable to reduce the level of compensation required. The real-time

compensation for the system deflection is achieved including a deflection model of the system in

the kinematics model and combining this with integrated load cells in the end effector. The

development of accurate robot positioning technology has greatly expanded the range of

applications for articulated arm robots within airframe assembly operations and will continue to do

so in the future both in point to point and path applications.

The integration of secondary encoders to each robot joint as described above gives actual axis

positions as opposed to inferred positions from motor encoders, this precision feedback when run

through an optimised kinematics model produces a motion platform of high accuracy and virtual

stiffness. Global positioning on-part accuracy below +/-0.25mm has been achieved using long

reach, heavy payload arms (refs (1), (2)), and from the above the additional hardware for

enhancement of a COTS robot system is minimal making it cost effective investment. Also neither

the range or flexibility of the arm is affected because the accuracy is achieved without guidance so

there are no line of sight issues to be taken into consideration.

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As a result articulated arm robots can be applied to a much broader range of assembly operations

including:- one up: two sided drilling and fastening: material removal and fibre placement.

In this study evaluations will be made of the accuracy of the articulated arm robots under virtual

assembly simulations in Catia V5.R20 kinematics and deflections under load will be analysed using

Catia V5.R20 GSA, and this will enable informed positioning and integration of the secondary

encoders as described above, the resulting models will show this positioning for future real world

experimental testing by other researchers figure 6 from reference 7 gives an indication of the level

of sophistication of the outputs of section 5 of this study in terms of establishing metrology

systems, tooling, and end effector devices, although the robot system fidelity, determination of the

robot systems working envelope through kinematic analysis, and load deflection GSA is not shown

in this figure these are key parts of this research.

Increasing airframe assembly rates also involves the elimination or at least the significant reduction

of the large monument fixtures and minimising the number of crane moves often required in large

airframe assembly. For example for a composites trimming operation the aerospace space supplier

PaR Systems Inc of Shoreview MN developed an overhead gantry KMT water jet cutting work cell

using 37 FANUC LR Mate 200iD series robots functioning as flexible fixtures precisely holding a

12.5m to 15.2m long aircraft components. This cell replaces the original system of purpose built

fixtures or using a pogo to hold the part at greatly increased cost. The robots provide six axes

articulation which supports the cells application to a range of variation, and the force control

sensors give the cell the ability to handle complex geometric shaped parts with great repeatability,

reducing costs and increasing processing rates.

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20

Figure 6:- Example of the structure of a flexible construction cell (reference 7).


Figure 7 from reference 7 illustrates some low complexity current flexible tooling that can be applied

across a range of assembly operations, and flexible tooling was and is used on the F-35 program.

Although as with purpose built tooling for multi national projects such as Airbus and Boeing

commercial airliners environmental control of the tooling is a very important issue to maintain

common assembly temperatures for major components of the fuselage for example to fit perfectly.

The application of automation to sealants especially for wing integral fuel tanks is another area of

development and work is being done by Nordson Sealing Equipment (of Plymouth MI), in to

developing new tools and applications software for sealant dispensing, and these systems could be

used for fay and filleting which shape the sealer similar to caulking but with higher degrees of

difficulty. Currently this is being done by hand due to the access requirements for sealing and the

need to control the bead shape and volume, as well as the requirement to inspect it. Therefore this

is a difficult and time-consuming process, creating a bottleneck even when the trough put of other

assembly stages are speeded up and enhanced by automation.

Airframe manufactures are keenly interested in developing new automation assembly operations to

the traditional applications of: - material handling; machine loading; assembly including drilling /

riveting / bolting / and stitching; surface preparation; painting; and sealant dispensing; etc. Gantry

robots are being explored for there heavy payload capacities and large work envelopes, and on the

shop floor six axis articulate arm robots with enhanced sensors for greater accuracy are being

explored mounted on tracks or free standing depending on their functions, as seen in figures 1-5,

and this will be explored in this study.

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22

Labour content of

production

Figure 7:- Example of flexible (realigned) assembly tooling (reference 7).


Additionally the movement of parts through the assembly plant is being is being automated in order

to eliminate some of the large high cost application specific monument fixtures and minimise the

number of time consuming crane moves which are often required with large airframe assembly.

According to Fori Automation Inc (Shelby Township. MI) (ref (6)) airframe assembly plants can

lower costs associated with delays in crane moves, while gaining precision positioning with the

latest generation of servo-controlled Automated Ground Vehicles (AGV‟s) which also have auto-

levelling technology to enhance positional accuracy. KUKA also produce a range of AGV‟s who

application will be explored in this study, as an alternative to fixed cell assembly. Fori currently

handles transportable drill units because airframe manufactures are transitioning away from

monument fixtures to autonomous vehicles, for example it is very practical and less costly to move

a drilling robot equipped with along the wing locking and docking anchors, rather than have a

number of fixed units. Currently the accuracy claimed by Fori is +/- 3mm on a parts that are 12.2m -

15.2m in length, however as drawn from reference (1) this accuracy could possibly be improved

with secondary encoders at the output axis of the joints and sensors on the end effector. To meet

the requirements for increased accuracy Fori AGV‟s are equipped with floor bushings which

increase their accuracy to 0.127mm and allow auto-levelling of the platform, and the company has

provided these systems to airframe subcontractors Brown Aerospace which is a supplier to Spirit

AeroSystems. These AGV‟s move large sub-assemblies weighing in the order of 49,500kg between

manufacturing stages including too and from autoclaves, before the application of these AGV‟s, this

was done by crane at times dictated by the crane availability. Now these movements are as and

when required. Functional robot mobility for the FATA wing project will be explored in sections 4

and 5 of this study. 23



The next section covers the construction, and development analysis of the assembly robots, the

construction and manipulation of the human builder and analysis their respective interactions. This

required starting with the SCARA (selective compliance assembly robot arm) Catia V5.R20

kinematic model and analysis, to gain a fundamental starting point for the design and analysis of

the more complex 6 DoF robots namely the ABB IRB4400/60,and the ABB IRB6650S_90. These

will be analysed for their maneuvering envelope and positional accuracy by simulation. The wider

application of automated assembly will also be examined in terms of component manufacturing

processes for example the stitching of component preforms as shown in figure 4, as well as the

application of flexible tooling to support structures in assembly as shown in figure 7 above.

In section 3 this is followed by an examination of current work in this field for example the Airbus

Automated Wing Box Assembly (AWBA) facility at Airbus Broughton, and the LOw Cost

Manufacturing and Assembly of Composite and Hybrid Structures), which is a collaborative

research project coordinated by SAAB AB, with 31 partners including key European aircraft

companies.

Ultimately in sections 4 and 5, an application study of the assembly of the outboard wing section of

both the FATA Baseline wing and the FATA PRSEUS wing will be undertaken applying lessons

learnt from the simulation and analysis studies, resulting in the production and assembly brake-

down of the FATA wing into build methodology for the automated build assembly and systems

integration section of my overall wing study.


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Section 2:- Kinematic modeling of robotic devices and the Human Builder.

The objective of this section is to construct robotic devices and analyses their movements in

assembly, and the interactions between robots and humans using the human builder manikin and

detail wing structural build components from the FATA wing design and manufacturing study both

for the baseline wing and for the PRSEUS wing (involving stitching robot cells). These assembly

studies are the content of sections 4 and 5.

This section will start with the construction of a simple three degree of freedom robot consisting of

two revolute joints and a prismatic joint, and then continue with the construction of the human

manikins (male and female) and their manipulation so they can interact with the next stage

developed robots in sections 4 and 5.

This robot configuration is often referred to as a SCARA (selective compliance assembly robot arm)

type robot. This initial exercise involves simulating the motion of the robot as its end effector (a

point at the tip of the last link for the purposes of this example) tracks a curve in space at constant

speed. This is representative of a number of typical robotic assembly tasks such as dispensing

adhesives, hemming sheet metal, etc.

For the purposes of this exercise the curve will represent a simple elliptical profile and the path

followed by the robots end effector will simulate the dispensing of adhesive on the rib flanges. For a

constant speed of 1in/s along the path, the requirement is to plot the angles of each of the two

revolute joints versus time. In a real world application, the robots controller would take these angles

and determine the joint torques (i.e. servo motor power levels) to apply to attain the desired motion.

This will be the first of a number of studies in this part work developing more complex robot

simulations as my work progresses. 25


The key elements of this first exercise the design and analysis of the SCARA are outlined below

and are based on the SDC Mechanism Design & Animation publication by Zamani. Nader. G. et al.

The stages are as follows:-

1) Modeling of the required robot components as Catia V5 parts:

2) Create an assembly (Catia V5 Product) forming the robot:

3) Constrain the assembly in such a way that the tip of the last link is on the curve and an

automatic assembly constraints conversion will produce the desired joints:

4) Entering the Digital Mockup workbench and converting the assembly constraints into two

revolute joints and a prismatic joint:

5) Creation of the Point Curve joint:

6) Simulate the relative motion of the assembly without consideration to time (i.e. without

implementing the time based linear velocity along the path):

7) Adding a formula to implement the time based kinematics:

8) Simulating the desired constant speed motion and generating plots of the two revolute joint

angles versus time.

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Overview of the basic three degrees of freedom SCARA design study exercise.


The design of this simple robot consisted of the modeling of four component parts consisting of:-

Link 1: Link 2: Link 3: and Base, in Catia V5 using the part design workbench as shown in figure 8,

and these were saved individually in Kinematic models file. The size of the robot is small and this

first exercise is intended for methodology proving rather than any real world application all

dimensions are shown in inches.

The Link 3 end effector has to track an elliptical path defined by a curve in space as stated

previously. This path was created as part of the base in this instance to save time as shown in

figure 9, although it could also be created as a separate part. Modeling the path as part of the base

unit began by loading the previously created Base part into Catia V5.R20 in the Part Design

workbench. Plane was selected from the Reference Element toolbar and in the resulting Plane

Definition pop up menu for Plane type Angle / Normal to plane was selected, the Rotation axis the

top edge of the Base unit bottom plate was selected as shown in figure 9, and for the Reference the

side face of the bottom plate was selected also shown in figure 9, an angle of 45º was used. The

track path was then created in Sketcher on this 45º plane as an ellipse measurements being taken

and constraints applied to ensure that no point on the path exceed 7” from the centre axis of the

base units central cylinder as the robot arm would be unable to reach any point on the path that

exceeded this planar distance when constructed to the selected dimensions.

With all of the components modeled the next stage was creation of the assembly in the Assembly

Design work bench using the icon in the start menu, (the alternative option to entre the

Assembly design work bench is through:- File > New > Product, which enters the Assembly

Design work bench) both options create an assembly with the default name Product. 1. 27

Construction of three degrees of freedom SCARA design study robot.


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Figure 8:- My components for the three degrees of freedom SCARA.

R = 0.25”

R = 0.4”

Link 1.

R = 0.125”

R = 0.4”

Link 2.

2.0”

4.0”

1.0” R = 0.5”

R = 0.25”

Base Unit.

5.0”

R = 0.25”

Link 3.

Selected surface.

Selected surface.

Selected surface.

Selected hole axis.

Selected axis.

Selected hole axis.


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Figure 9:- My base component with application path for SCARA simulation.

For Rotation axis this edge was selected.

For Reference this plane was selected.

Robot end effector track path plane.

Robot end effector track path.

Robot arm Base Unit.


The creation methodology for production assemblies shown in Chart 1 was followed to create a

new assembly of the small robot component parts. In the Properties box of Product.1 the part

number was amended to Small_Robot_Arm_Test and the Source amended to Made. With the

Product highlighted the robot component parts were inserted from the Kinematics model file using

Insert > Existing Component and selecting parts Link_3: Base: Link_1: and Link_2. Using Move

in the Manipulation tool set these components were rearranged to eliminate overlapping thus

enabling easier picking in constraint creation process.

Assembly constraints (figure:- 10):-

1) First the Base was fixed in position using the Anchor icon from the Constraints toolbar, this

removed all six degrees of freedom for the base.

2) The next stage was to impose the constraints on the Base and Link_1 (the objective being to

remove all relative degrees of freedom except for the rotation about the common axis), thus

creating a revolute joint between the two parts, and a combination of a coincident constraint

and a surface contact constraint was used to achieve this. This assembly being associative and

exact the Coincidence constraint (see chart 2) was applied between the central axis of the

Base and the hole axis of Link_1 (as shown as red dashed line in figure 8), then a Contact

constraint was applied by selecting the annular surface of the Base and the surface of Link_1

(see figure 8).

3) The next stage was to apply the constraints between Link_1 and Link_2 applying the same

combination of constraints i.e. Coincidence between the hole axis of Link_1 (shown in gold in

figure 8) and the part axis of Link_2, and a Contact constraint between the surfaces. 30

Construction of three degrees of freedom SCARA design study robot (cont.).


Chart 1:- Creation Methodology for Production Assemblies.

Verify Position of Data Position as required

N

Y

Is a Key

Diagram

available?

Does

Production

Assembly

exist?

Does Data

already

exist?

Is Reference

Geometry modelled

in local axis?

Start

Y

N

N

Open Production Assembly Create Production Assembly

Insert Existing Data Add New Data

Y Snap data to Key Diagram

N

Y

No Hyperlink

Hyperlink to Task

KEY

31


Chart 2:- Catia V5. R20 Assembly Positioning Options.

Various positioning options are available in Catia V5.R20 assembly design.

The functions illustrated are available in the Assembly Design and Digital Mock-Up (DMU)

Navigator workbenches

These functions illustrated have been used by myself at BAE Systems and will be employed in the

FATA project.

32


3) The next step was to impose the constraints between Link_2 and Link_3, creating a prismatic

mechanism joint between these two components, this required removing all of the relative

degrees of freedom apart from the translation along the vertical axis. To achieve this a

Coincidence constraint was applied between the hole centre axis in Link_2, and the central

axis of Link_3 (see figure 9), this effectively removes all but translation and rotation about that

axis. The unwanted rotation was removed by applying an Angular Constraint and selecting the

zx planes of Link_3 and Link_2 respectively (see figure 9).

4) The final constraint application was to put Link_3 into physical contact with the application path

generated earlier in the Base model. This was required before the Point Curve Joint could be

created in the Digital Mockup (DMU) workbench. To achieve this two points were created one

on the curve, and the other in the centre of the bottom surface of Link_3, and a Coincidence

constraint was allied to connect them. Once the tip of Link_3 was in contact with the application

path the coincidence constraint was deleted to prevent generation of a spherical joint in the

mechanism due to this constraint.

Creating Joints in the DMU workbench (figure:- 11):-

The Kinematics workbench was accessed via Start > Digital Mockup > DMU Kinematics, and in

this workbench the Assembly Constraints Conversion icon was selected which enables the

creation of most common joints automatically from the existing assembly constraints. In the

Assembly Constraints Conversion (ACC) box New Mechanism was selected and the default name

Mechnism.1. The ACC box indicated Unresolved pairs: 3/3. To create the joints Auto Create was

selected and the Unresolved pairs changed to 0/3 indicating that the joints had been created. 33



34

Figure 10:- My three degrees of freedom SCARA with constraints in DMU workbench.

End effector.

Application path.

Moving arm links.

Fixed base.

Angular Constraint.

Anchor Constraint.


Expanding the Applications branch of the tree confirmed this, at this stage the degrees of freedom

was three representing the three independent motions of the joints because the path constraint had

yet to be imposed. The Point Curve Joint was created manually, selecting the Point Curve Joint

icon and selecting the application path as Curve 1: and the point at the bottom of Link_3 as Point 1:

then OK. These joints are shown in the tree in figure 11 with the completed small robot assembly.

The degrees of freedom was reduced to one indicating that the resultant mechanism could be

simulated as soon as a command was specified, and this was achieved by double clicking on the

Point Curve 4 branch to open the definition box and setting to Length driven, and receiving the

Mechanism can be simulated message on closure.

Initial Simulations (figures:- 12&13):-

Two initial simulations were undertaken to verify path motion and clash detection in the joints these

did not have laws applied, using the Simulation icon and Mechanism.1. as the only one present

(this gives a choice to simulate one of a number of mechanisms if more than one has been

created). The resulting Kinematics Simulation box enabled manual scrolling of the simulation to

check the motion path and for any clashes, which was verified with no clashes. At the end of the

manual scroll the insert button was pressed in the Edit Simulation pop up box to activate the video

player as shown in figures 12 and 13.

In this mode a mechanism motion MPEG video and a replay were created for the small robot arm

assembly, the MPEG video is too large to post on my LinkedIn profile but is available for screening

at interview if requested. 35



36

Figure 11:- My three degrees of freedom SCARA with joints generated in the DMU.

Revolute joint.

Revolute joint.

Prismatic joint.

Point Curve joint.


37

Figure 12:- My SCARA, DMU motion / clash simulation check no laws applied.


38

Figure 13:- My SCARA, DMU motion / rate simulation check no laws applied.


Creating Laws in the Motion Simulation:-

Time based physics was introduced into the mechanism to enable the required plotting of the

angles of the two revolute joints versus time over the application path. This was achieved by

specifying the linear velocity of Link_3 along the application path, with the desired speed of 1 in/sec

as specified in the study introduction section.

The Simulation with Laws icon was selected in the Simulation toolbar resulting in the Kinematics

Simulation: Mechanism.1 pop up box being displayed indicating that a relation between the

command and the time parameter is required (see figure 14). This relation was created using the

Formula icon (see figure 13) from the Knowledge toolbar which activated the Formulas:

Small_Robot_Arm_Test pop up box to be displayed. The Mechanism.1, DOF=0 branch was

selected in the tree (see figure 13), in order that only parameters associated with the mechanism

were displayed in the Formulas box, which reduced the number of parameters to two:-

Mechanism.1\KINTime and Mechanism.1\Commands\Command.1\Length, the latter parameter

was selected and Add Formula button was activated to enter the Formula Editor box, in this box

Time was selected in the Member of Parameters column, and then Mechanism.1\KINTime was

selected in the Members of Time column. As length can be computed as the product of linear

velocity (1in / 1s) in this case and time, the box containing the right hand side of the equality was

edited so the formula became:-

Mechanism.1 \ Commands \ Command.1 \ Length = (1in / 1s)*Mechanism.1\KINTime

This was accepted and OK was pressed closing the box this resulted in the formula being displayed

as a Law in the Mechanism.1, DOF=0 branch as shown in figure 14.

39



40

Figure 14:- My SCARA, DMU with time laws applied of 1in/sec.

Law applied to Mechanism 1. Formula icon.

Mechanism .1, DOF=0 branch.


A verification simulation was then run using Simulation with Laws, the default simulation duration

was 10 seconds, this value was changed to the measured value of the application path length

14.988in and the number of steps was changed to 360 representing a complete rotation around the

application path as shown in figure 15.

In order to obtain the required plots the Activate sensors box was clicked at the bottom left corner

of the simulation box, (see figure 15), this resulted in the Sensors box being activated as shown in

figure 16, the sensors were activated to record the angles of each of the two revolute joints:-

Mechanism.1\Joints\Revolute.1\Angle

Mechanism.1\Joints\Revolute.2\Angle

The number of steps was reset to 80 (the lager the number the smoother the plot (see figure 15).

The scroll bar in Kinematics Simulation was used to move the robot joints to track Link_3 down

the application path once one revolution had be completed the Graphics button in the Sensor box

was pressed displaying the plots for the Revolute.1 joint between the base and Link_1, and for

Revolute.2 joint between Link_1 and Link_2, as shown in figures 17, and 18 respectively.

Figure 19 shows some still image captures from the Simulation MPEG.

This concluded this initial robot simulation exercise, as stated above the intention of this part of the

FATA project is to simulate robotic assembly of the baseline wing and the new developed wing

using PRSEUS technology. Discussed in the subsequent slides are the issues to be investigated

and an idea of the robots to be simulated, this is an overview only at this stage of study.

41



42

Figure 15:- My SCARA, simulation with DMU time laws applied of 1in/sec.

Activate sensor check box.


43

Figure 16:- My SCARA, DMU with time laws applied of 1in/sec and sensors selected.


44

Figure 17:- My SCARA, DMU angle versus time plot for Revolute Joint 1.


45

Figure 18:- My SCARA, DMU angle versus time plot for Revolute Joint 2.


46

Figure 19:- Stills form my SCARA Catia V5.R20 DMU mpeg movie capture.


This subsection is intended to provide an introduction to the Ergonomic Design & Analysis

workbench of CATIA V5.R20 in order to create and manipulate male and female human builder

manikins that will be used in sections 4 and 5 of this study. The Ergonomic Design & Analysis

workbench covers the following modules:- Human Measurement Editor: Human Activity

Analysis: Human Builder: and Human Posture Analysis, although this subsection will focus on

the Human Builder alone the other elements will be explored in sections 4 and 5.

The Human Builder module is accessed through Start > Ergonomic Design & Analysis >

Human Builder in the application screen the properties were inputted as Product name:- Male

Human: Revision:- 1A: Definition:- Jerry, and a brief description. Subsequently this new manikin

was inserted using insert a new manikin from the toolbar as shown in figure 20(a) below. The

parameters were set in the New Manikin Properties Dialog Box as follows:- Father Product =

Male Human: Manikin Name = Jerry: Gender = Man: Percentile (population) = 99.9% and when this

box was OK the manikin was created as shown in figure 20(b), and then the Anthropometry for

the manikin was set in Properties in study American was used which generated a height Stature of

2025.066mm and a Weight of 123.233kg.

In the following figures basic manipulation was studied of the leg, arm, and hand, as well as

incorporation of the builder in an assembly these are shown in figures 21(a) through 21(g). The first

manipulation was to define and select a “Predefined Posture” this was accomplished entering the

Posture Editor Dialog Box through the Posture Editor Icon as shown in figure 21(a), the

manikins thigh was selected from the Segments selection menu as well as Right in the Side

selection, this heighted the right thigh of the manikin orange as shown in figure 21(a). 47

Kinematic modeling of robotic devices and the Human Builder.


48

Insert New Manikin Tool.

New Manikin Properties Dialog Box.

Figure 20(a):- Human Builder Insertion and parameters setting.


49

Figure 20(b):- Human Builder generation.

Input Manikin Anthropometry in

Properties dialog box accessed by

clicking manikin in tree.

Posture Editor Icon.


50

Figure 21(a):- Manipulation Human Builder (Right Thigh) to Predefined Posture “sit”.

Posture Editor Icon.

Posture Editor Input Panel.


Kinematic modeling of robotic devices and the Human Builder (continued).

With the Degrees of Freedom set to flexion / extension the Predefined Posture of Sit was

selected from a menu which has the following options:- Initial (hands out in front, arms bent, legs

straight) as shown in figure 20(b) and 21(a); Stand (arms at side of body, and legs straight); Sit as

shown in figure 21(b); Span (arms stretched out at right angles to the body and legs straight); and

Kneel (legs bent back and arms bent out in front), this resulted in the rotation of both right and left

legs into the “steady state” sitting posture, as shown in figure 21(b) which is fine for simulating a

human at rest say a passenger on an airliner.

However suppose an activity is to be simulated like operating a foot control with the right leg only.

In order to achieve this a rotation greater than the Predefined Posture setting was required hence

the Value slider was used to impart the degree of movement of the right thigh to 100%, and hence

the right leg alone in its bent form was rotated relative to the body and left leg as shown in figure

21(c). Note the left leg remained in the Predefined Sit Position because one is able to select

individual body parts to move relative to the rest.

The Angular Limitations for each limb or hand or finger can on the manipulation of the manikin as

shown in figures 21(d) and 21(e) which illustrate lower right leg and upper right arm manipulation

respectively same applies to the left side.

The Human Builder is designed to be incorporated into assemblies as this is the fundamental

reason for having the manikin capability in the first place, shown in figure 21(e) is male manikins in

such assembly model that is the male human builder with the ABB IRB4400/60 and ABB

IRB6650S_90 as a size comparison covered later in this section and cover illustration shows both

the male and female human builders next to my study ABB robots.

51


52

Figure 21(b):- Manipulation Human Builder (Right Thigh) to Predefined Posture “sit”.


53

Figure 21(c):- Manipulation Human Builder (Right Thigh) outside Predefined Postures.


54

Figure 21(d):- Manipulation and analysis Human Builder outside predefined postures.


55

Figure 21(e):- Manipulation and analysis Human Builder outside predefined postures.

Clash detection on.


56

Figure 21(f):- Human Builder in an assembly with study robots.

Male Human Builder

(Jerry).

ABB IRB4400/60 Robot.

ABB IRB6650S_90 Robot.


57

Figure 21(g):- Manipulation of the hand and arm of the Human Builder.

Human Builder Measurement and

Posture Workbench Icons.



Figure 21(g) illustrated further the fidelity of the Human Builder Manikin by manipulation of the

fingers of the left hand to hold some part or device.

Next the Female Manikin was created using the same methodology as the previous male manikin

Jerry this new manikin was named Betty and is shown opened in the Human Posture Analysis

Workbench in figure 22(a) accessed by the icon shown in figure 21(g), in this workbench the

angular joint limitations can be set, edited, optimised, or removed, and the DoF (Degrees of

Freedom) locked, as well as the posture assumed scored.

The critical dimensions of the Female Manikin were examined both in standing and standing and

sitting postures as shown in figures 22(b) and 22(c) in the Human Measurements Editor

Workbench, accessed by the icon shown in figure 21(g), where the variables in each critical

measurement can be evaluated and the percentile values can be changed when the Manual to

increase or decrease the size of any of the listed attributes. In both the Human Measurements

Editor and the Human Posture Analysis workbenches the gender and race of the manikin can be

changed as shown in figure 22(c).

The next functionality explored were the Manikin Movement Tools in this tool set the simulated

reach was created between an imported existing component Platform.1, and the female manikin

using Reach (position only) as shown in figure 23(a) this put a compass following the same axis

orientation as the imported part, the left hand was then selected to produce the actual reach of the

manikin shown in figure 23(b). The complete reach movement envelope for the left hand and upper

body was then produced by selecting the Reach Envelope icon in Manikin Tools and the dialog

inputs shown in figure 23(c) the envelope is shown with a degree of transparency in pink. 58


59

Figure 22(a):- The Female Human Builder in Posture Analysis Workbench.

Human Builder Female (Betty)

Line of sight.


Right Arm.


Left Arm.


Right Leg.


Left Leg.


Head.

Edits angular limitations

Optimises angular limitations

Sets angular limitations

Locks DoF

Removes angular limitations

Scores posture


60

Figure 22(b):- The Female Human Builder in Measurement Editor Workbench Standing.


61

Figure 22(c):- The Female Human Builder in Measurement Editor Workbench Sitting.

Set to manual to

change percentile.

Changes gender

Changes race


62

Figure 23(a):- The Female Human Builder Movement Workbench:- Reach.

Reach (position only) icon.

Inserted Existing Component:- (Platform.1)

Select Left Hand

Reach Compass


63

Figure 23(b):- The Female Human Builder Movement Workbench:- Reach.

Selected Left Hand

movement to compass

Reach (position only) icon.


64

Figure 23(c):- The Female Human Builder Movement Workbench:- Reach envelope.

Reach Envelope

Computation icon.

Reach Envelope setting

dialog box.

Left Hand movement

envelope

Left Hand selected

Left Hand clash with

platform detected.


To complete this evaluation of the manikin manipulation the twist, lean, and centre of gravity tools

were explored as detailed below and illustrated in figures 24(a) through 24(c) below.

The first evaluation was twist, and Standard Pose was selected from the Manikin Posture

Toolbar as shown in figure 24(a), the Twist tab was selected in the dialog box, and a twist angle of

-51º was entered in the dialog box using the arrow keys.

The second evaluation was lean, and the Standard Pose was again selected from the Manikin

Posture Toolbar as shown in 24(b), the Lean tab was selected in the dialog box, and a lean angle

of -20º was entered in the dialog box using the arrow keys therefore the female manikin Betty was

twisting and leaning simultaneously in this simulation.

The third evaluation was to determine the manikins Centre of Gravity this was accomplished using

the Change Manikin Display icon as shown in figure 24(c) and selecting Centre of Gravity in the

dialog box.

This concluded the basic evaluation of generation and manipulation of the Human Builder Manikins

that will be used in sections 4 and 5 of this study and has covered the most important aspects of

manipulation and space envelopes which will be covered in depth for human / robot workspace

interactions.

65



66

Figure 24(a):- The Female Human Builder Standard Posture Workbench:- Twisted.

Standard Pose icon.

Pose dialog box

Twist selected

Twist angle

selected


67

Standard Pose icon.

Pose dialog box

Lean selected

Lean angle

selected

Figure 24(a):- The Female Human Builder Standard Posture Workbench:- Leaning.


68

Change Manikin Display Icon.


The following is an overview of the ABB IRB4400/60 articulated arm robot from ABB published

data:- This robot is stated to be a extremely fast robot of compact design suited to medium and

heavy handling operations and has all round capabilities, making it suitable for a variety of

manufacturing applications. This would appear to make it suitable for the assembly operations

envisioned in sections 4 and 5 of this study. The load capacity is of this model is 60kg which means

that its load carrying capabilities are well within the projected weights of the components of the

FATA outboard wing assembly, in fact for general handling the robot may be able to handle two or

more sub-components at a time. A rigid well-balanced design and patented TrueMove™ function

provides smooth and fast movement through the entire working range. This would ensure very high

quality in cutting applications and similar high tolerance applications, and the rapid manoeuvrability

of the IRB 4400/60 see table 1, would make it a good match for applications where speed and

flexibility are important and with precision placement this would be what is sought in rib placement.

The compact design and protected versions enables the application of the IRB 4400/60 to many

situations were other robots could not work such as foundry and spraying operations. The robust

and rigid construction gives long intervals between routine maintenance. Well-balanced steel arms

with double bearing joints, a torque-strut on axis 2 and the use of maintenance-free gearboxes and

cabling, contribute to a high degree of reliability. As well as an optimised drive train for high torque

at the lowest power consumption of economic operation benefit this robots consideration.

Extensive communications capability includes serial links and network interfaces, PLC, remote I/O

and field bus interfaces, enabling easy integration in both small manufacturing stations and large

scale factory automation systems.

69



70

Table 1:- ABB Data sheets for the IRB 4400/60 robot from reference 3.


71

Figure 29:- Surface Model of the ABB IRB4400/60 robot for Kinematic model data.


Figure 30:- Dimensions and working range of the ABB IRB4400_60 robot.

All dimensions are in mm. Figure 30:- IRB4400_60

72


The following is an overview of the ABB IRB9950S_90 articulated arm robot from ABB published

data:- The IRB 6650 Self robot offers a unique working envelope which will be explored in relation

to the assembly needs of all sections of the FATA wing in this study. The IRB 6650S is capable of a

full vertical and horizontal stroke motion, as well as increased reach forward and down. This

combination offers new possibilities to robot functions in numerous application areas. A variation

on this robots press tending capabilities could be application to the removal of parts from

autoclaves for the baseline wing and CAPRI ovens for the PRSEUS wing components. The

increased working area of the robot would make it possible retract from these environments with

large parts or grippers, at high rates. High acceleration power is combined with a unique stroke

horizontally as well as vertically, and this combination could shorten cycle times and thereby

increase production capacity. Also the working area below the robot offers an excellent opportunity

for fast tool changing of grippers. The IRB 6650S is especially suited for large injection moulding

machines over 1,000 tones, and the flexibility of the six axis robot facilitates post processing

operations like framing, sprue cutting, tape dispensing and assembly operations.

For materials handling owing to its longer reach forward and down, when mounted on an elevated

track it could supervise twice as many inlet conveyors with different part sizes as a traditional

ceiling mounted or wall mounted track with a 5 – or 6 – axes robot. When compared with an

inverted track and a 5 – axes robot, the length of track for the IRB 6650S can be kept much shorter

and thereby simplifying installation and reducing overall costs. This is an interesting robot and has

the potential for application in the FATA wing design and assembly study, or even the Phase 2

Condor fuselage study. Table 2 gives the manufactures data sheets for all three versions of the

IRB 6650S robot.

73



74

Table 2:- ABB Data sheets for the IRB 6650S_90 robot from reference 3.


75

Figure 31:- Surface Model of the ABB IRB6650S_90 robot for Kinematic model data.


76

Figure 32(a) (b):- Dimensions and working range of the ABB IRB6650S series robots.

All dimensions are in mm.

Figure 32(a): - IRB6650S-90/3.9 Figure 32(b): - IRB6650S-125/3.5


77

Figure 32(c):- Dimensions and working range of the ABB IRB6650S series robots.

Figure 32(c): - IRB6650S-200/3.0


78

Figure 33:- Comparison of the sizes of the ABB study robots and the Human Builder.

Male Human Builder

(Jerry).

Female Human

Builder (Betty).

ABB IRB4400/60 Robot.

ABB IRB6650S_90 Robot.


Current research into methods of assembly have introduced a degree of automation for example

the Airbus Automated Wing Box Assembly (AWBA) figure 18(a) at Broughton.

The AWBA development cell conducts the automated loading of spars and ribs into the vertical

assembly jig which is of gantry construction with an upper raft fixed below the gantry cross member

holding the tooling for mounting the leading edge spar, and a lower raft close to floor level which

holds the tooling for mounting the trailing edge spar.

After fixing the spars, the ribs are then loaded in build sequence, by the assembly robot and each

spar has machined in pockets to accept the ribs and the robot has to manipulate each rib into these

two sets of pockets. In order to accomplish this the assembly robot is rail mounted and has a

pivoting axis in addition to its three linear X,Y,Z axes. The sequence is to take a rib from the store,

tilt it at approximately 45º to the vertical using the pivot axis, move it into position so that it locates

into the trailing edge (lower) spar pocket, then rotate the rib to the vertical so that it locates into the

leading edge (upper) spar pocket, and after insertion the rib is held in place hydraulically.

Locating the ribs into the spars requires the robot to achieve an accuracy of +/- 0.5mm (0.02”)

which is a degree of precession equitable to large transport airframe structures. To achieve this the

same type of laser tracker system is used as that used in BAE Systems MA&I assembly of

Typhoon, F-35, Mantis, and Taranis, namely the Leica LTD800 figure 18(b) which is capable of

measuring accuracies of +/- 0.05mm (0.002”) over distances of 35m (114ft). The units motorized

head directs the laser beam over a 3-D volume of up to 70m (229ft) in diameter to locate and

measure the 3-D co-ordinates of target reflectors which can be 3 D of F, or 6 D of F, figures 18(c)

and 18(d) respectively at the measurement positions. In the AWBA the transmitter unit is located on

one of the gantry legs but it is also portable.

Section 3:- Advanced assembly technology relevant to the FATA Baseline Wing.

79


Figure 18(b):- Leica LTD800 with T-Cam.

Figure 18(a):- Airbus Automated Wing Box Assembly Cell.

Figure 18(c):- 3Degrees of Freedom Ball Prism system.

0.5” TBR reflector 1.5” Cats Eye

Figure 18(d):- 6Degrees of Freedom reflector system.

Figure 18:- Robotic assembly example the Airbus AWBA cell systems.

80


The next operation after fixing the ribs is skin wrapping where skin sets are taken from the store

and simultaneously placed against pads on both sides of the ribs either two or four at a time and

then clamped by a series of programmable pneumatic clamps. Working from both sides balances

the load when both clamps are applied and avoids the necessity of constructing a very stiff

supporting structure. The skin sets cover the trailing (lower) and leading (upper) sections of the

wing box, leaving the centre section open to allow access for internal fastening, and in production

for manual assembly and inspection.

Fastening the wing skins to the ribs involved both internal and external operations for which two

separate robot systems were developed. The external hole drilling operation and fastener insertion

was undertaken by a standard Kuka K350 six axis robot which was rail mounted to provide a

seventh motion axis and equipped with a sophisticated end - effector developed by BAE Systems

ATC. This end – effector incorporates a vision sensor, high speed spindle drilling head stud

inserter as shown in figure 19.

Before the skin wrapping operation takes place the robot uses its vision sensor, consisting of two

cameras, and four laser rangefinders to locate the 3-D position of each pad on the rib. This

geographical location data is stored by the robot so that when the skin is mounted in position the

robot knows the exact location to drill through the skin and pad in a single operation. Each pad

requires four fasteners and the robot is capable of drilling, deburring, the four holes, and inserting

all four studs in a cycle time of 15 seconds per hole. During these operations all six of the robots

axes are locked in position so that it becomes an “end-effector positioner” development of the

optimum drilling parameters and cutting conditions to ensure maximum hole quality, and minimum

burr size were undertaken by AEA. 81

Advanced assembly technology relevant to the FATA Baseline Wing (continued).


82

Figure 19:- External robot consisting of a Kuka industrial robot equipped

with special tooling for locating rib pads, drilling and stud insertion.

AEA also conducted modal analysis and

vibration trials on the robot to the effects of

these factors on hole accuracy when drilling

automatically.

Swaging of the fastening collar to the end of the

stud inserted by the Kuka robot is undertaken

by an internal robot developed by RTS

Advanced Robotics. Because of the restricted

opening into this demonstrator wing box

approximately 1m x 1.5m and the 5.5m reach

to access the back of fasteners through the far

side skin RTS could not use off the shelf

technology and a “special” robot was

developed. This robot has 10 degrees of

freedom and a reach of 6.5m. Its constituent

parts are the development robot, a telescopic

boom that swivels about a horizontal axis, and

is mounted on a linear track to permit access to

the full length of the wing box, and a standard

Fanuc six axis parallel leg robot. The latter is

fitted to the end of the boom arm and acts

basically as its end effector.



The ultimate tooling consisting of the swaging unit with collar feed and stereoscopic vision sensor

(developed by BAE Systems ATC) which is mounted at the end of the legged robot. This sensor

guides the robot to locate the stud end so that the tooling can dock with the stud the collar then

slides over the stud and is pulled tight before it is swaged onto the stud. The internal robot is

designed to behave like any other industrial robot, with the obvious exception that positioning for

setup and programming id conducted by teleoperator control in order to avoid the operator or

programmer from being in any potential danger within the confines of the wing box and to overcome

the problem of a large and heavy robot arm in a remote position. Using the teleoperator system the

end effector is positioned remotely using television cameras that form part of the tooling to observe

movement. As a further safety measure, the robot arm is fitted with capacitance sensors to detect

the onset of a collision, whether during teleoperational set up, or automatic operation.

Airbus UK stated that the test work carried out in AWBA cell has met all expectations and has

proven the concept for wing skin panel wrapping for metallic wing boxes, and is capable of handling

and positioning 6m long wing ribs quickly and safely. It will continue to use the cell to asses the

scale up implications as well as the impact of automatic assembly methods on aerodynamics

systems installation, and health and safety.

A more recent (i.e. 2013 to 2016), composites advanced manufacturing study has been the

LOCOMACHS (LOw Cost Manufacturing and Assembly of Composite and Hybrid Structures),

which is a collaborative research project coordinated by SAAB AB, with 31 partners including key

European aircraft companies, with the objective of creating cost effective part manufacturing and

assembly of composite, metal and hybrid airframe structures.

83



In so much as I am able using the resources I have available, the published findings of this project

will be evaluated and incorporated into my research where appropriate. The assembly of composite

airframe parts opens alternatives to the methods developed for metallic assembly rather than

merely using a composite component as a straight replacement for a metal one (the “black metal”

approach used on early composite airframes), however composites assembly is more challenging

than the traditional assembly of machined metal components as dealt with in the AWBA cell. The

LOCOMACHS project aims to develop emerging technologies and integrate them with existing

technologies to create cost effective part manufacturing processes and assembly methodologies for

future airframes, the scope of the Research and Technology Development activities of this project

which are being addressed simultaneously covering different areas of the product development

cycle from product design through airframe structural assembly are outlined below in figure 20.

The published project objectives are not dissimilar from my own private research but on a much

grander scale using real world articles and testing where as I am limited to virtual design and

analysis. These objectives are listed below:-

1)More accurate parts and fewer structural joints:- A set of design and manufacturing rules will be

defined and validated taking into account architectural, time and cost constraints to reach more cost

effective assembly to be used in design phase of product development.

2)Shim reduction:- The reduction in the non-added value shimming operations by:- (a)Better

knowledge of the manufacturing process (i.e. spring-in process simulation, statistical process

control (SPC), tool design), leading to the production of more accurate parts: (b)Innovative part

assembly architecture and novel joint design of structural joints (a major thrust of my project):

(c)Use of materials requiring less curing time for more efficient shimming. 84



85

Figure 20:- The scope of the LOCOMACHS research and development project.


86

3) Optimized integrated geometrical tolerance and variation management:- The geometrical

tolerance and variation management will be optimized and fully integrated in a representative

airframe assembled wing box structure.

4) Optimized assembly:- (a)The use of one-way assembly to avoid temporary assembly

operations: (b)Development of more cost effective measurement and verification

methodologies: (c)The use of flexible assembly tooling (as used on F-35) to handle variations in

airframe parts see also figure 5.

5) Increased automation:- (a)Development of a fully integrated automated assembly process:

(b)Development of safe solutions to human-robot co-working operations.

6) Innovative Non Destructive Testing / Non Destructive Inspection technologies:- (a)More

integration of the NDT / NDI operations on the in situ components: (b)More flexible, compact

and faster processing of inspection results: (c)More automation in the handling of NDT / NDI

sensors e.g. „C-scan‟ ultrasonic probes.

To meet these research objectives the LOCOMACHS project will asses all of the above

developments through advanced physical and virtual demonstrators outlined below:-

Physical Demonstrators (see figures 21(a) / 21(b)):-

1. Lean Assembly Wing Box (LAWiB) this is an assembled structure with a low level of part

integration consisting of front and rear spar sections, four ribs, and upper and lower cover skins

and connecting parts. It is planned to be of mixed composite and metallic components.



2. More Integrated Wing Box (MIWiB) based on the same part design as the LAWiB but with a

much higher level of integration this demonstrator will consist of a section of a wing box with

integrated front and rear spars, two ribs, lower cover skin, and an assembled upper cover.

Virtual Demonstrators:- Based on extrapolations of the feasibility test results to representative

large complex aircraft assembly units, and is to based on:-

1. Reference Wing Box (REWiB), a complete wing box airframe structure where the focus is on

demonstrating a virtual lean production flow including both manufacturing and assembly

processes in a lead time and physical handling perspective figure 21(a). This is along the lines of

my current research project.

2. Reference Fuselage (REFus), which will focus on the design of individual features included in

the interfaces in a fuselage structure. This is covered by my research only to the extent of the

wing carry through box interface with the centre fuselage, and the wing fairing.

Results as of 2013:- During the first year LOCOMACHS has worked on the definition of the design

architecture figure 21(b), and build philosophy of the future demonstrators. Partners in all

domains from industry and academia alike, have proposed a total of 84 technical targets, with

associated product – and production requirements. To assure that all targets have the required

Technology Readiness Level TRL for integration, rigorous TRL-methodology is being applied to

all targets. Based on their expected final TRL level and feasibility within LOCOMACHS the most

promising targets have been chosen for integration into the demonstrators.

87



88

Figure 21:- LOCOMACHS research and development project demonstrators.

Figure 21(a):- Wing box assembly demonstrators both

physical and virtual ref LOCOMACHS phase one

report.

Figure 21(b):- GKN Aerospace LAWiB Wing box

assembly physical demonstrator (ref:- GKN Aerospace

Technology publication 2014 Farnborough Airshow.


A preliminary design based CAD models for all parts to be integrated into the demonstrators have

been used to create a baseline digital mockup (DMU), validated and distributed to partners during

the preliminary design review (PDR). The baseline DMU is to be continuously updated as partners

evolve their respective targets toward the LOCOMACHS high level objectives and progress has

been made in the following domains:-

a)More accurate parts and fewer structural joints:- (1) Targets defined for lean manufacturing of more accurate

parts and early development has begun on these (initial trials and supplier selection): (2) Current design of part

interfaces is being improved to allow for high-level part integration on LAWiB and MIWiB. Proposals for solutions

and evaluations of integrated skin stringers and integration of metal parts design has been made using different

approaches: (3) Novel design features for shim-less, simplified jig systems for large assemblies and hybrid joint

design solutions have been defined.

b)Less Shimming:- (1) Innovative shimming processes using conceptual solutions for new methodologies have

been tested: (2) Technical targets to demonstrate technologies to manufacture integrated structural parts with less

assembly have been defined: (3) Improvements in the design process by more accurate simulation of processing

phenomena have been developed e.g. the use of “Shell-elements” to simulate spring back rather than “Volume-

elements” (my current studies also explore this in Workbook 2): (4) Technical targets for tolerance management

have been defined including:- Flexible Tolerancing for composite structures, Statistical Tolerancing and

visualization and Statistical modeling of part variations. Composite-specific characteristics for design, manufacture

and use have been defined as well as the specification for non-rigid, statistical variation simulation for

composites.

c)Optimized assembly:- Current flexible tooling has been evaluated and requirements for new tooling have been

defined. 89



d) Automation:- (1) Several targets for structural assembly sub-operations have been defined, e.g. drilling,

fastening, one-way assembly, sealing, masking, fastening and hole inspection: (2) Different collaborative

strategies for robot / human interaction in the same working space have been defined: (3) Pre study for the

assembly for the assembly order for the LAWiB completed and will allow the development of a demonstrator

for tracking the 4th rib (see figure 77(b)) to the LAWiB using a robot –human collaborative solution.

e) Novel and Lean NDT /NDI technologies for composite materials and structures:- Target technologies

have been defined within the areas of Laser Ultrasonics (LUT), Air Coupled Ultrasonics (ACUT), Acoustic

Emissions (AE), Acosto Ultrasonics (AUT), and Phased Array Ultrasonics (PA UT).

The expected impact of this research is:-

50% reduction of the recurring costs of non-added value shimming operations:

30% reduction of the recurring costs of non-added value dismantling operations:

30% reduction of the recurring costs related to part assembly by increasing the level of

automation:

30% reduction of NDT / NDI lead time.

This is the type of project I would like the opportunity to contribute to and I hope to some degree my

current research efforts and academic qualifications and industrial experience demonstrate my

abilities in this area of research.

The thrust of my work as stated above will be to model robotic assembly of the baseline FATA wing

and the developed PRSEUS wing structure using robots designed from catalogue data and custom

end effectors. 90



IN WORK.

91

Section 4: - Development support for the automated assembly of the FATA wing.


IN WORK

92

Development support for the automated assembly of the FATA wing (continued).


IN WORK

93

Section 5: - Automated assembly of the FATA Baseline Outboard Wing Section.


IN WORK

94

Automated assembly of the FATA Baseline Outboard Wing Section (continued).


1) Expanding the use of robotics in airframe assembly via accurate robot technology 2010-01-

1846: by Russell De Vlieg of Electroimpact, Inc: Published by SEA International 2010.

2) Automatic Wing Box Assembly Developments: by Brian Rooks: Published in Industrial Robot,

(An international journal) Volume 28. Number 4. 2001. pp. 297-301 MCB University Press

ISBN 0143-991X.

3) ABB Robotics at www.abb.com/robotics for all product datasheets and surface models of the

IRB4400/60 robot and the 6650S_90 robot.

4) Catia V5 Tutorials in Mechanical Design and Kinematics Release 20: by Nader G. Zamani, and

Jonathan M. Weaver: Published by SDC Publications ISBN:-978-1-58503-652-3 in 2011.

5) FATA Wing Design Study of the American Institute of Aeronautics and Astronautics: by Mr.

Geoffrey Allen Wardle. MSc. MSc. Snr MAIAA.: Published as progress updated on LinkedIn

Slide share.

6) Aerospace Automation Stretches Beyond Drilling and Filling: by Patrick Waurzyniak Senior

Editor: Published on Advanced Manufacturing.org April 2015 pages 73-86.

7) Automated Assembly of Aircraft Structures(Training Modules for young researchers, Master

and Doctorial Students: by Dr Yu. A. Vorobyov, Dr V. V. Voronko, Dr I. A. Voronko: Published

by the National Aerospace University “KhAI” in 2013.

8) Automated Solutions for 2D and 3D Preform Production: by Guido Jaeger of KLS: Presented at

the Composites Europe 2014 VDMA Composites Forum.

9) LOCOMACHS

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Reference material in use for this presentation.


9) Laser and feedback for robotics in aircraft assembly: by Albin Sunnabo: Published through

Linkopings University Sweden IRSN:- LITH-ISY-EX-3470-2003: 19th December 2003.

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Reference material in use for this presentation.

my new kinematics and aircraft assembly robotics studies 28th august 2016

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