MODELING AND COMPENSATION OF HYSTERESIS NONLINEARITY IN DYNAMICAL SYSTEMS

Abstract

This work deals with the design of an output-feedback nonlinear controller to compensate the hysteresis captured by a piezoelectric actuator. The control is based on the position measurements only due the lack of sensors. A simple and practical nonlinear observer is designed for a Hammerstein structure to estimate the state of the hysteretic subsystem and the internal state of the linear dynamics subsystem. Such an observer and thus the nonlinear control law work well where the hysteretic system is modeled as classical Bouc-Wen model. The output-feedback scheme for the controller is simple to implement. No additional computations are required once the identification of parameters of model is achieved. Simulation results shows how efficient the control is. The results also show the robustness of the closed-loop under external perturbations which are assumed to be unknown and unmodeled.