Compensation of rate-dependent hysteresis nonlinearities in a piezo micro-positioning stage

Piezo micro-positioning actuators have been widely used in micro-positioning applications due to the fast expansion, high force generation, and unlimited resolution. However, these actuators exhibit some rate-dependent hysteresis effects which affect the accuracy of these micro-positioning systems and may even lead to system instability. In this paper, the rate-dependent Prandtl-Ishlinskii model is employed to characterize the rate-dependent hysteresis nonlinearities of a piezo micro-positioning stage. The analytical inverse of the rate-dependent Prandtl-Ishlinskii model is then formulated using the initial loading curve concept. This inverse is utilized as a feedforward compensator to compensate for the hysteresis nonlinearities of a piezo micro-positioning stage under excitation in the 1-50 Hz frequency range.