Sliding mode observer based hysteresis compensation control for piezoelectric stacks

Piezoelectric stacks (PS) are wildly used as actuator mechanism for precise instrument in practical engineering. Nevertheless, hysteretic effect that is carried by the piezoelectric materials can degrade the control performance dramatically. For the purpose of improving the control precision, the problem of hysteresis compensation control for PS system is investigated in this paper. First, in order to compensate the hysteretic effect, two kinds of observers are proposed. The design of the observers has considered external disturbance and the creep effect in PS system. By utilizing Lyapunov function and linear matrix inequalities (LMI) technique, the observers can asymptotically estimate the hysteretic output with H-infinity performance. Second, a hysteresis-compensation based back-stepping controller is established. The design of the controller has considered the observation error, and it has a certain robustness. At last, numerical and experimental simulations are carried out to verify the effectiveness of the proposed methods.