Two-Degree-of-Freedom Hysteresis Compensation for a Dynamic Mirror Actuator

A low-computation, high-bandwidth, inverse-based hysteresis compensation and control strategy, not needing a priori knowledge of the desired trajectory, is presented. The resulting two degree-of-freedom controller is applied to a dynamic mirror with antagonistic piezoelectric stack actuation. Hysteresis compensation is performed by a finite-state machine activating polynomials for hysteresis inversion based on input signal slope. Residual error after hysteresis compensation is corrected by an LQR feedback controller. Experimental results demonstrate effectiveness of the hysteresis compensator and closed-loop system. For the input signal tested, a 91.5% reduction in hysteresis uncertainty is achieved at a 60 kHz sample rate.