Compensator-based position control of an electrorheological actuator

Abstract

This paper addresses the question of whether compensator-based controllers can be used to successfully control the position of a model scale robot arm attached to the output shaft of an electrorheological (ER) actuator, with a view of recommending the actuator for robotic applications and providing an alternative control strategy to proportional plus integral plus derivative, (PID), control. An ER actuator is a device that uses a ‘smart’ material, called an ER fluid or suspension, as a coupling medium between the prime mover running at a constant speed and a load. Three compensator-based controllers—the phase-lag, the phase-lead and lead-lag compensators—were designed and implemented on the ER actuator-arm system. The phase-lead and phase-lag compensators gave reasonable performance. The lead-lag compensator, on the other hand, was impossible to implement.