Stepping motors : a guide to theory and practice

Contents......Page 6
Preface to the fourth edition......Page 10
1.1 Introduction......Page 12
1.2.1 Principles of operation......Page 13
1.2.2 Aspects of design......Page 16
1.3 Single-stack variable-reluctance stepping motors......Page 17
1.4 Hybrid stepping motors......Page 19
1.5 Comparison of motor types......Page 21
2.1 Introduction......Page 24
2.2 Unipolar drive circuit......Page 25
2.2.1 Design example......Page 26
2.3 Bipolar drive circuit......Page 27
2.3.1 Example......Page 28
2.4 Bifilar windings......Page 29
2.4.1 Example......Page 32
3.2 Static torque/rotor position characteristics......Page 36
3.3 Position error due to load torque......Page 38
3.4 Choice of excitation scheme......Page 40
3.4.1 Variable-reluctance motors......Page 41
3.4.2 Hybrid motors......Page 44
3.4.3 Mini-step drives......Page 45
3.5 Load connected to the motor by a gear......Page 47
3.6 Load connected to the motor by a leadscrew......Page 48
3.6.1 Example......Page 50
4.1 Introduction......Page 52
4.2 Relationship between pull-out torque and static torque......Page 53
4.3.1 The mechanism of resonance......Page 59
4.3.2 The viscously coupled inertia damper......Page 62
4.3.3 Electromagnetic damping......Page 66
5.1 Introduction......Page 70
5.2.1 Circuit representation of the motor......Page 72
5.2.2 Calculation of pull-out torque......Page 76
5.2.3 Example......Page 80
5.3.1 Circuit representation of the motor......Page 82
5.3.2 Torque correction factor......Page 85
5.3.3 Calculation of pull-out torque......Page 88
5.3.4 Example......Page 90
5.4.1 Drive requirements......Page 91
5.4.2 Bilevel drive......Page 92
5.4.4 Chopper drive......Page 95
5.5 Instability......Page 97
6.1 Introduction......Page 100
6.2 Starting/stopping rate......Page 101
6.2.1 Example......Page 104
6.3 Acceleration/deceleration capability......Page 105
6.3.1 Example......Page 108
6.4 Implementation of open-loop control......Page 111
6.4.1 Microprocessor generated timing......Page 112
6.4.3 Hardware timing......Page 114
6.4.4 Pulse deletion......Page 116
6.4.5 Analogue ramp up/down......Page 117
6.5 Improving acceleration/deceleration capability......Page 119
6.5.1 Example......Page 121
7.1 Introduction......Page 122
7.2 Optical detection of rotor position......Page 124
7.3.1 Switching angle to maximise pull-out torque......Page 126
7.3.3 Example......Page 129
7.3.4 Control of switching angle......Page 131
7.4 Alternative position detection techniques: waveform detection......Page 133
7.4.1 Waveform detection using motional voltage......Page 134
7.4.2 Waveform detection using phase inductance......Page 136
7.4.3 Example......Page 139
7.5 Closed-loop against open-loop control......Page 140
8 Microprocessor-based stepping motor systems......Page 142
8.2 Software vs hardware for open-loop control......Page 143
8.2.1 Constant rate operation......Page 144
8.2.2 Ramped acceleration/deceleration......Page 149
8.2.3 Example......Page 154
8.3 Microprocessor-based closed-loop control......Page 155
8.3.1 Control of switching angle......Page 156
8.3.2 Deceleration initiation and adaptive control......Page 158
9 Appendix: pull-out torque/speed characteristics of bifilar-wound motors......Page 160
References......Page 162
Further reading......Page 166
Index......Page 168