Input excitation-based refined hysteresis identification and compensation for piezoelectric actuators of satellites

This paper proposes an input excitation-based refined hysteresis identification and compensation method for piezoelectric actuators of satellites in an on-line manner. The whole process is divided into a hysteresis parameter identification phase and a hysteresis compensation phase. In the first phase, based on the Bouc-Wen model of complicated hysteresis nonlinearity, an input excitation signal with piecewise ramp function is specifically designed, and thereafter an input excitation hysteresis observer (IEHO) is proposed. Compared with traditional observers, the adverse effect generated by the uncertain derivative of control input can be overcome by the proposed IEHO. Based on the IEHO outputs, a parameter identification method is designed to obtain the parameter estimates of hysteresis nonlinearity. In the second phase, a novel refined hysteresis observer (RHO) is proposed to estimate the hysteresis nonlinearity, where the updated Bouc-Wen hysteresis model has been fully utilized with the aid of parameter identification results. By combining the RHO with one full-order terminal sliding mode controller, a composite controller is designed to achieve the finite-time trajectory tracking and refined hysteresis compensation simultaneously. Finally, numerical simulation and experiment verification are provided to show the effectiveness of the proposed methods.