Hybrid Estimation Strategy-Based Anti-disturbance Control for Nonlinear Systems

In this article, an anti-disturbance control design is presented for nonlinear systems based on a hybrid disturbance estimation scheme. This scheme features the capability of making full use of the incomplete knowledge on disturbance dynamics. By embedding the known information, the disturbance interval observer is developed to generate boundaries to cover individually each element of external disturbances. Through synthesizing a tangent barrier Lyapunov function-based estimation switching mechanism, the modified disturbance observer is proposed to take appropriate values between the boundaries as the estimation. By using this estimation, the anti-disturbance control compensates for external disturbances. It is proved that the system states stay within a specified region and converge to a small neighborhood of the origin. Finally, the numerical simulation is presented to illustrate the effectiveness and benefits of the estimation scheme and the control design.