Adaptive variable structure controller for affine nonlinear systems with uncertainties

The output tracking of a class of affine nonlinear systems with unmatched-uncertainties was discussed. In respect that the parameters of system are uncertainty, a control scheme based on the theory of Lyapunov stability is proposed. When system error is bigger then a certain value, adaptive design method is combined with variable structure control to design an adaptive VS controller, in which the closed loop system is globally stable, parameter estimation is convergent, the signal of system keeps limitary, and the VSC is forbidden when system error close to zero, so the chattering phenomenon is avoided. Academic study and simulation results confirm that the adaptive VS controller is correct and effective.