Adaptive Sliding Mode Control of Hysteresis in Piezoelectric Actuator

Piezoelectric actuators are favorable choices for reaching ultrahigh precision in motion control and positioning, which are necessary in many applications. This is due to their fine resolution, response speed and output force. The nonlinear dynamics of piezoelectric actuators is an obstacle to this goal, and hysteresis is the major challenge that can deteriorate the actuator performance. In this study, sliding mode control with proportional-derivative (PD) sliding surface is adopted, using a Bouc Wen model of hysteresis. Mismatch of this model with the actuator behavior is considered as an unstructured uncertainty. Asymptotic stability is proved using Lyapunov theorem. Structured uncertainty in model parameters is also unavoidable, so an online parameter estimator is proposed to compensate for those uncertainties. The parameters' adaptation rule is derived so that asymptotic stability is guaranteed. Simulation results show the performance of the proposed algorithm. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.