Robust output feedback control with disturbance estimation for piezoelectric actuators

Abstract

This paper proposes an output feedback sliding mode control (SMC) combined with a sliding mode observer featuring a PID-type sliding surface for the positioning and tracking of a piezoelectric actuator (PEA) system. The considered PEA system is subjected to model imperfection, creep nonlinearity, hysteresis nonlinearity and other external effects. These uncertainties can be addressed by the proposed sliding mode control, and the PID-type sliding surface offers a fast convergence and a smooth control of the PEA. With only the measured output available for feedback, the observer reconstructs the full state in finite time and provides an estimate of the unknown uncertainties of the PEA system. The stability of the proposed controller is proved through Lyapunov-based stability analysis. Experiments are conduced to verify the feasibility and effectiveness of the proposed control system. Both set-point positioning and tracking control are realized with good performance and the PEA system with high-accuracy can be achieved. Moreover, the observer is verified that it can accurately estimate the uncertainties of the PEA system with external disturbance through simulation.