Shear stress tracking control of an electrorheological fluid considering hysteresis non-linearity

Abstract

This paper presents shear stress tracking control of an electrorheological (ER) fluid actuator subjected to the hysteresis non-linearity. As a first step, polymethylaniline (PMA) particles are prepared and mixed with silicone oil to make an ER fluid. The Couette-type electroviscometer is employed to achieve the field-dependent shear stress. The Preisach model for the PMA-based ER fluid is identified using experimental first-order descending (FOD) curves. A compensation strategy is then formulated in a discrete manner through the Preisach model inversion to achieve the desired shear stress of the ER fluid. A proportional-intergal-derivative (PID) feedback controller is also integrated with the compensator in order to guarantee control robustness to uncertainty due to temperature-dependent hysteresis variation. The tracking performance of the control strategy is experimentally evaluated for two different desired shear stress trajectories.