This paper presents an enhanced tachometer model that takes into account the effect of electromagnetic coupling that can exist between the actuator and sensor in an integrated dc motor-tachometer assembly, where the conventional model is found to be inadequate. The tachometer dynamics identified in this paper is experimentally verified, and incorporated in the modeling and parameter identification of a motion system that has multiple flexible elements. It is shown that the tachometer dynamics contributes additional nonminimum phase zeros that degrade the servo system performance in terms of closed-loop bandwidth, disturbance rejection and sensitivity to modeling uncertainty. The zeros of the open loop system are found to vary with the geometric parameters of the motor-tachometer assembly. Based on the insight gained by modeling the electromagnetic coupling, methods for eliminating it and its resulting detrimental effects are also suggested.

Issue Section:
Technical Briefs
Keywords:
Servomotor Control, Tachometer Model, Sensor Actuator Crosstalk, Electromagnetic Coupling, Zero-Locus, electromagnetic coupling, machine control, servomotors, motion control, DC motors, tachometers, electric actuators, electric sensing devices, parameter estimation, closed loop systems, uncertain systems, open loop systems
Topics:
Engines, Motors, Tachometers, Manufacturing, Sensors
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 by ASME
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