Table of Contents
1 Feedback Control Theory 1
1.1 Linear System 1
1.2 Nonlinear Systems 2
1.3 Linearization Technique 3
1.4 Laplace Transform 4
1.5 Transfer Function 7
1.6 First Order Transfer Function 8
1.7 Frequency Response 10
1.8 Second Order Transfer Function 11
1.9 Block Diagram Representation 13
1.10 Frequency Response 15
1.11 Conclusion 16
2 Feedback Control Theory Continued 17
2.1 Introduction 17
2.2 Routh-Hurwitz Stability Criteria 17
2.3 Root Locus Method 19
2.4 Nyquist Plot 23
2.5 Bode Diagram 28
2.6 Steady State Error 39
3 State Variable Feedback Control Theory 43
3.1 Introduction 43
3.2 State Variables 44
3.3 Eigenvalues, Eigenvectors, and Characteristic Equation 47
3.4 State Variable Feedback Control Theory 50
3.5 Dynamic Observer 55
3.6 Controllability and Observability 56
3.7 Conclusion 58
4 Electrical DC Servo Motors 59
4.1 Types of DC Servo Motors 59
4.2 Types of Power Unit 60
4.3 Speed Torque Characteristic of DC Servo Motors 62
4.4 DC Servo Motors in Open and Closed Loop Velocity Control 63
4.5 DC Servo Motors in Closed Loop Position Control 66
4.6 DC Servo Motors for Very High Performance Requirements 68
4.7 Properties of Power Unit 77
5 Stepping Servo Motors 81
5.1 Principal Operation 81
5.2 Stepping Motors with Small Step Angle 83
5.3 Torque-Displacement Characteristics of a Stepping Motor 84
5.4 Dynamic Response Characteristic over One Step Movement 86
5.5 Speed-Torque Characteristic Behavior of Stepping Motors 87
5.6 Stepping Motors for Position Control Applications 88
6 AC Servo Motors 91
6.1 Principle of Operation 91
6.2 Variable Speed AC Motors 91
6.3 Mathematical Model 92
6.4 FrequencyConverter 97
6.5 Conclusion 102
7 Electrohydraulic Servo Motors 103
7.1 Introduction 103
7.2 A Simple Mechanically Controlled Servo System 104
7.3 Electrohydraulic Servo Valves 107
7.4 Hydraulic Servo Motors 109
7.5 A Numerical Investigation of the Transient Behavior of an Electrohydraulic Servo Motor Under Different Conditions 112
7.6 Conclusion 117
8 Actuators Based on Electro-Rheological Fluid 119
8.1 Introduction 119
8.2 Some Possible Applications of ER Fluid 120
8.2.1 Valves 120
8.2.2 ER Clutch and Catch Type Actuators 120
8.2.3 Variable Dampers Based on ER Fluid 121
8.3 Properties of ER Fluid in Flow Mode 122
8.4 Properties of ER Fluid in Shear Mode 127
8.5 Conclusion 129
9 The Choice and Comparison of Servo Motors 131
9.1 Introduction 131
9.2 Theory and Performance Criteria 132
9.3 Comparison of Results and Design Procedure 135
9.4 An Example on Choosing a Servo Motor 145
9.5 Conclusion 146
Appendix A Exercise Problems on Classical Feedback Control Theory (Chapters 1 and 2) 149
Appendix B Exercise Problems on State Variable Feedback Control Theory (Chapter 3) 173
Appendix C Exercise Problems on Servo Motors (Chapters 4-9) 197
C.1 Electrical DC Servo Motors 197
C.2 Electrical Stepping Servo Motors 209
C.3 Electrical AC Servo Motors 213
C.4 Electrohydraulic Servo Motors 216
C.5 Actuators based on Electro-Rheological Fluid (ERF) 220
C.6 Selection of a Servo Motor for Particular Applications 223
Index 225
