Adaptive Fuzzy Inverse Compensation For Actuator Dead-zone With Piecewise Time-varying Parameters

Existing adaptive control methods for canceling actuator dead-zone nonlinearity are restricted to an assumption that the dead-zone parameters are constants. But in realistic circumstances, such assumption cannot be always satisfied because the dead-zone parameters may vary with time and even experience abrupt jumps. To address this issue, a new adaptive fuzzy control strategy is proposed to handle such dynamic dead-zone characteristics. Specifically, our scheme is developed with a modified tuning functions method and a novel piecewise Lyapunov analysis. Moreover, to improve the system transient performance in the presence of the dynamic dead-zone nonlinearities, prescribed performance bounds based method is incorporated with the backstepping design. It is proved that besides the system stability, the tracking error is always preserved in a predefined compact set irrespective of the sudden parameter jumps. Simulation example demonstrates this conclusion.