Improved Sliding-Mode Disturbance Observer for Nonlinear System

The uncertainty of the model and the external disturbance can badly influence the control effect. At present, many scholars have proposed different kinds of disturbance observers based on the various theories for the nonlinear system. In this paper, the performance of a class of disturbance observers for nonlinear system is analyzed, and an improved method is proposed for this type of observers, and the stability of the improved observer is proved too. Finally, the performance of the improved observer is compared with the old one by simulation. According to the simulation results, the improved observer has higher estimation precision and stronger robustness.