State Constraint Control for Uncertain Nonlinear Systems With Disturbance Compensation

In this paper, a state constraint controller with disturbance compensation is proposed for uncertain nonlinear systems to improve the control performance without violating the full state constraints. A series of extended state observers are designed to estimate disturbances that include the unmodeled dynamics and the modeling errors. To guarantee non-violation of state constraints while compensating the disturbances, based on the backstepping technique, the state constraint controller with extended state observer is proposed by using the barrier Lyapunov function. Then, the stability of the closed-loop system is proved theoretically. Moreover, exponentially asymptotic tracking is achieved when the disturbances are not time-variant. Finally, the effectiveness of the proposed approach is verified by two examples.