Title :
Step-Rate Modulation and Piecewise Linear Control to Adapt Stepping Motors to Low-Bandwidth Servos
Author :
Bilane, Glenn B.
Author_Institution :
Advanced Control Technology, Inc., Ivyland, PA 18974.
Abstract :
Stepping motors provide precise digital control of speed, without tachometer feedback, and have no brushes to wear. This makes them useful in feedback control systems. However, the stepping motor´s natural resonance and its requirement for limited acceleration can cause sustained vibrations and overshoots. Modulating a stream of stepping pulses at twice the resonance frequency with special sequences of ones and zeros overcomes resonance problems. Using a piecewise linear function relating the target stepping rate to the position error prevents saturated overshoots. This function can be generated automatically from more basic parameters of the control system.
Keywords :
Acceleration; Brushes; Digital control; Feedback control; Piecewise linear techniques; Pulse modulation; Resonance; Resonant frequency; Servomechanisms; Servomotors;
Journal_Title :
Industrial Electronics, IEEE Transactions on
DOI :
10.1109/TIE.1987.350925