Stepper Motors--Theory and Practice--Article Index

1 Stepping motors

• 1.1 Introduction
• 1.2 Multi-stack variable-reluctance stepping motors
• 1.2.1 Principles of operation
• 1.2.2 Aspects of design
• 1.3 Single-stack variable-reluctance stepping motors
• 1.4 Hybrid stepping motors
• 1.5 Comparison of motor types

2 Drive circuits

• 2.1 Introduction
• 2.2 Unipolar drive circuit
• 2.2.1 Design example
• 2.3 Bipolar drive circuit
• 2.3.1 Example
• 2.4 Bifilar windings
• 2.4.1 Example

3 Accurate load positioning: static torque characteristics

• 3.1 Introduction
• 3.2 Static torque/rotor position characteristics
• 3.3 Position error due to load torque
• 3.4 Choice of excitation scheme
• 3.4.1 Variable-reluctance motors
• 3.4.2 Hybrid motors
• 3.4.3 Mini-step drives
• 3.5 Load connected to the motor by a gear
• 3.6 Load connected to the motor by a leadscrew
• 3.6.1 Example

4 Multi-step operation: torque/speed characteristics

• 4.1 Introduction
• 4.2 Relationship between pull-out torque and static torque
• 4.3 Mechanical resonance
• 4.3.1 The mechanism of resonance
• 4.3.2 The viscously coupled inertia damper
• 4.3.3 Electromagnetic damping

5 High-speed operation

• 5.1 Introduction
• 5.2 Pull-out torque/speed characteristics for the hybrid motor
• 5.2.1 Circuit representation of the motor
• 5.2.2 Calculation of pull-out torque
• 5.2.3 Example
• 5.3 Pull-out torque/speed characteristics for the variable-reluctance motor
• 5.3.1 Circuit representation of the motor
• 5.3.2 Torque correction factor
• 5.3.3 Calculation of pull-out torque
• 5.3.4 Example
• 5.4 Drive circuit design
• 5.4.1 Drive requirements
• 5.4.2 Bi-level drive
• 5.4.3 Example
• 5.4.4 Chopper drive
• 5.5 Instability

6 Open-loop control

• 6.1 Introduction
• 6.2 Starting/stopping rate
• 6.2.1 Example
• 6.3 Acceleration/deceleration capability
• 6.3.1 Example
• 6.4 Implementation of open-loop control
• 6.4.1 Microprocessor generated timing
• 6.4.2 Example
• 6.4.3 Hardware timing
• 6.4.4 Pulse deletion
• 6.4.5 Analogue ramp up/down
• 6.5 Improving acceleration/deceleration capability
• 6.5.1 Example

7 Closed-loop control

• 7.1 Introduction
• 7.2 Optical detection of rotor position
• 7.3 Switching angle
• 7.3.1 Switching angle to maximize pull-out torque
• 7.3.2 Choice of fixed switching angle
• 7.3.3 Example
• 7.3.4 Control of switching angle
• 7.4 Alternative position detection techniques: waveform detection
• 7.4.1 Waveform detection using motional voltage
• 7.4.2 Waveform detection using phase inductance
• 7.4.3 Example
• 7.5 Closed-loop against open-loop control

8 Microprocessor-based stepping motor systems

• 8.1 Introduction
• 8.2 Software vs hardware for open-loop control
• 8.2.1 Constant rate operation
• 8.2.2 Ramped acceleration/deceleration
• 8.2.3 Example
• 8.3 Microprocessor-based closed-loop control
• 8.3.1 Control of switching angle
• 8.3.2 Deceleration initiation and adaptive control

9 Additional material: pull-out torque/speed characteristics of bifilar-wound motors