Tracking Control of an unknown switched nonlinear system based on adaptive backstepping with nonlinear disturbance observer

In this paper, an adaptive control schemes to solve the output tracking control problem of a class of nonlinear switched systems in presence of the disturbance is proposed. First, an nonlinear disturbance observer (NDO) is designed and the  backstepping scheme is constructed based on the standard Lyapunov function method for tracking purpose. With the propose scheme, the existence of a standard Lyapunov function for all subsystems with unknown parameters infers the global uniform asymptotic stability of this more generic switched system The switching parameters used in the switching system are defined differently for each subsystem. Analyzing the system's stability proved that the closed-loop signal boundedness under arbitrary switching is well ensured. It is shown that the proposed adaptive anti-disturbance control scheme based on a nonlinear disturbance observer is a suitable control approach for a class of nonlinear switched systems.