A New Disturbance Rejection Control Scheme for a Class of Controlled Dynamic Nonlinear Systems

A new disturbance rejection control scheme is proposed for a class of controlled dynamic nonlinear systems in this paper. As is well known, the linear controller is valid to stabilize dynamic nonlinear systems even when these systems are affected by small amplitude disturbances. But, unfortunately, it may be unstable when the amplitude of the disturbance increases, which is undesirable. To overcome this undesired phenomenon, a compensation system (sensitive system) is introduced into the linear controller in this paper, by which the controlled dynamic nonlinear systems can be approximately linearized and the disturbance amplitude can be rejected. Our new disturbance rejection control scheme is described. First, the proposed sensitive system is connected to the controlled dynamic nonlinear system to form an interconnection system. Then, an adaptive state feedback controller is synthesized for the sensitive system to asymptotically guarantee the original stability of the controlled dynamic nonlinear system with large disturbance amplitude. Finally, the effectiveness of our new disturbance rejection control scheme is verified by the simulation example.