Ultimate stability analysis of active disturbance rejection control with a high-gain observer

Model uncertainty is an important issue that must be considered when designing or analyzing controllers. So focusing on a class of nonlinear systems with model uncertainties, this paper analyzed the tracking performance of the active disturbance rejection controller with a high-gain observer, through transforming the model uncertainties into the error form, and the closed-loop system was proved to be ultimately bounded using Lyapunov function and Gronwall-Bellman inequality. Finally, numerical simulations demonstrate the results.