Adaptive failure compensation of hysteric actuators in controlling uncertain nonlinear systems

Hysteresis nonlinearity exists in many physical actuators and actuator failures seem inevitable in practice. However, there is still no result available to compensate for failures of hysteric actuators in the design of controllers based on adaptive approaches. In this paper, we address such a problem by considering controlling a class of unknown nonlinear systems with multiple hysteric actuators. Two schemes are presented to design control signals for these actuators. Both schemes can accommodate uncertain patterns, values and time of actuator failures, in addition to system parametric uncertainties. It is shown that the designed controllers can compensate for failure and hysteresis effects of the actuators in the sense that system stability and tracking performance are maintained no matter whether this is any actuator failure or not.