Invariance Control of a Class of Cascade Nonlinear Systems With Input Unmodeled Dynamics

The paper addresses the invariance control for a class of cascade nonlinear systems with unmodeled dynamics appearing at the input. A sufficient condition for the robust invariance control of the system under consideration is derived. Based on the methods of passivity and switching control of states of the linear subsystem, both the stabilization of the linear subsystem and the positive invariance of the prespecified region in state space can be ensured. Under some additional assumptions, the whole system is semi-global asymptotically stable. A simulation example is given to demonstrate the effectiveness of the proposed design procedure.