Robots and automated manufacture

Edited by J. Billingsley

Peter Peregrinus Ltd. on behalf of the Institution of Electrical Engineers

Contents

Editor's Introduction xi

1 A novel steering mechanism for legged robots 1 1.1 Introduction 1 1.2 Methods of simplification 1 1.3 Design of the hexapod 8 1.4 Results and conclusions 8

2 The use of simulation in the off-line programming of robots 11 2.1 Introduction 11 2.2 The build solid modeller 12 2.3 The form of a robot simulation system 12 2.4 The components of a robot simulation system 14 2.5 Application example: condition number analysis as an aid to

workpiece positioning 21 2.6 Conclusion 23

3 The practical problems involved in off-line programming a robot from a CAD system 29

3.1 Introduction 29 3.2 Programming techniques 29 3.3 Repeatability and accuracy tests 30 3.4 Error compensation 32 3.5 Improved calibration procedures 32 3.6 Conclusions 33 3.7 Acknowledgements 33

4 The application of rule based methods to inspection and quality control in a manufacturing process 41

4.1 Introduction 41 4.2 The manufacturing process to be controlled 42 4.3 The controller 42 4.4 Inspection theory 42 4.5 Experimental results 43 4.6 Conclusions 44

5 Automatic location editing of assembly robot programs 55 5.1 Location editing feasibility and use 55 5.2 The location edit task 58

vi Contents

5.3 Experimental results 62 5.4 Discussion 64 5.5 Conclusions 65

6 Dynamic analysis of industrial robots using decentralised control via kinematics 73 6.1 Introduction 73 6.2 Mathematical model of the system 74 6.3 Control algorithm and its implementation 75 6.4 Prescribed trajectories/kinematics 77 6.5 Simulation procedure 78 6.6 Example 80 6.7 Conclusion 83

7 Collision avoidance between robots operating in the same cell 99 7.1 Robot cells and flexible operations 99 7.2 Route Consultant (RC) specification 101 7.3 Cell-specific knowledge 103 7.4 The manufacturing process 105 7.5 Practical viability 107

8 Flexible automated assembly systems 111 8.1 Introduction 111 8.2 Specification of flexible assembly systems 112 8.3 Flexible assembly system configuration 113 8.4 Research programme 113 8.5 Conclusions 114

9 Autonomous assembly devices and related control strategies 121 9.1 Introduction 121 9.2 Passive and active accommodation 121 9.3 Autonomous units developed at U.W.I.S.T. 122 9.4 Control strategies 124 9.5 Conclusions 128

10 An aid to effective off-line programming of assembly robots 129 10.1 Introduction 129 10.2 Interactive user-friendly language 130 10.3 Off-line programming 130 10.4 Specification for the compliant fixture 132 10.5 Design of the device 134 10.6 Experimental tests 134 10.7 Conclusions 136

11 Robot force sensing using stochastic monitoring of the actuator torque 139 11.1 Introduction 139 11.2 Actuators as force feedback sensors 139 11.3 Stochastic monitoring of the actuator's torque 140 11.4 Case study 141 11.5 Results and conclusions 144

12 Precise measurement of radial dimensions in automatic visual inspection and quality control—a new approach 157 12.1 Introduction 157

Contents

12.2 Inspection of circular products 158 12.3 Radial histograms 159 12.4 A new approach to the sensitive measurement of radius 161 12.5 Concluding remarks 169

13 Visual feedback control for orientating parts in an assembly robot cycle 173 13.1 Introduction 173 13.2 Magiscan vision system 174 13.3 Host processor/robot communications 174 13.4 Application to disc orientation 175 13.5 Conclusions 176

14 Automation and robotisation in welding—the UK scene 185 14.1 Introduction 185 14.2 Applications 188 14.3 Statistics 189 14.4 Government support 192 14.5 Related studies and developments 193 14.6 Comment 195

15 Practical industrial low cost vision for welding robots and automated welding machines 199

15.1 Summary 199 15.2 Introduction 199 15.3 Survey of potential industrial users 199 15.4 Design objectives 200 15.5 System overview 201 15.6 Experimental results achieved 206 15.7 Assessment of results and conclusions 209 15.8 Acknowledgements 209

16 A high-speed pattern recognition system for robotic applications 211 16.1 Introduction 211 16.2 Systems specification 212 16.3 Systems overview 212 16.4 Systems hardware 214 16.5 Systems performance 216

17 A vision system for the identification of motor car headlamp reflectors for robotic assembly 221

17.1 Introduction 221 17.2 Problems 223 17.3 Systems hardware 223 17.4 Systems task 224 17.5 Systems software 226 17.6 Operation 227 17.7 Time saving methods 228 17.8 Conclusion 229

Index 231