Adaptive Backstepping controller design for nonlinear system with uncertain coefficient of control input

An improved adaptive backstepping controller design method is proposed for a class of higher-order single input and single output nonlinear system with non-strictly parameter feedback uncertainty. For uncertain coefficient of control input in system model, existing nesting problem that the designed controller includes parameter adaptive law and the adaptive law includes control input are solved effectively by using equivalent model transform and selecting the suitable Lyapunov function. The proposed method is applied to position tracking control of hydraulic servo system, and an adaptive backstepping controller is designed. Simulation results show that the proposed controller has good robustness and position tracking performance.