Output feedback control for nonholonomic systems with nonvanishing disturbances and asymmetric time-varying constraints

In this paper, an adaptive output feedback control scheme is introduced for nonholonomic systems with nonliner uncertainties, nonvanishing disturbances, and output constraints. A tan-type barrier Lyapunov function is considered to address asymmetric time-varying output constraints. We define the disturbance as the generalized system state. The extended state observer is proposed for uncertain external disturbance. A new estimator is designed for unknown parameter and states. It is shown that under the backstepping technique the output feedback adaptive controller ensures the stability of the closed loop system, while the asymmetric time-varying output constraints are not violated. The simulation results of mobile robot system are provided to validate the effectiveness of the presented control approach.