Abstract
Hysteresis is one of the key factors that adversely affect the tracking performance of piezoelectric actuators in many applications. In this paper, a sliding mode control (SMC) augmented with uncertainty and disturbance estimator (UDE) and hysteresis compensator to achieve high tracking performance while maintaining robustness is first proposed. After which, its adaptive version is derived to enhance the adaptability. The benefits of the proposed approach are: (1) it is inherently chattering-free; (2) does not require a reference model for UDE; and (3) can track both periodic motion and non-periodic motion. The stability of the proposed method is verified through Lyapunov technique. Guidelines for selection of control parameters are also demonstrated through simulation. Experimental studies are conducted to verify the effectiveness of proposed methods. The result shows that both proposed methods surpass the performances of proportional-integral-derivative controller, adaptive SMC with hysteresis compensator and SMC-UDE in terms of tracking performance, while the proposed adaptive SMC-UDE with hysteresis compensator is superior to the proposed SMC-UDE with hysteresis compensator in terms of the speed to steady state.