Prescribed-performance-based adaptive fuzzy tracking stagey for nonlinear systems

This paper was motivated by the problem of longitudinal motion control for nonlinear system of unmanned vehicles. In complex environments, the GPS sensors often suffers to time-varying delay and thus affecting the control performance. This paper designs an adaptive backstepping strategy based on fuzzy observer to solve the above problem. Firstly, we established the nonlinear dynamic equations of the unmanned vehicle system under time-varying delay and disturbances. To suppress the effect of time-varying delay, an adaptive fuzzy observer is proposed to predict the system state. To ensure the control effectiveness, a prescribed-performance scheme is proposed to limit the error. Based on the observer and the preset performance scheme, an adaptive backstepping controller is proposed. Both simulation and experiment indicate that the proposed method is feasible and effective.