Stabilization of a class of nonlinear systems with actuator saturation via active disturbance rejection control

The stabilization problem of a class of nonlinear systems with actuator saturation is investigated via active disturbance rejection control (ADRC). We first present results for systems with nonlinear ADRC and show that local stabilization can be achieved in a region including the origin. Then, for the linear ADRC, the linear matrix inequality (LMI) conditions for determining the estimate of the domain of attraction of the resulting closed-loop system are formulated based on a quadratic candidate Lyapunov function and a generalized sector condition. An LMI-based algorithm is correspondingly established to design the linear ADRC controller. The obtained results suggest a new way to stabilize the saturated nonlinear system, even in the case that the state of the system is not fully available for measurement and system nonlinear dynamics are largely unknown. An illustrative example validates the effectiveness of the proposed approach.