High Gain Disturbance Observer-Based Control for Nonlinear Affine Systems

This paper proposes a high gain disturbance observer based control approach for nonlinear systems. Compared with previous works, it can admit a much larger class of disturbances produced by nonlinear exo‐systems. Our approach will follow the framework of the two‐stage design procedure, which separates the disturbance observer design from the controller design. Under certain conditions, the observer error for the disturbances generated by nonlinear exo‐systems globally and asymptotically converges on zero and the stability of the closed‐loop system is guaranteed. An illustrative example of a two‐link robot manipulator with limit cycles disturbance is presented to show the effectiveness of the proposed method.