Robust adaptive output sampled control of uncertain system with unknown time-varying control coefficient based on characteristic model

摘要

The robust adaptive control of uncertain system with unknown time-varying control coefficient is discussed. A novel output sampled control scheme based on characteristic model with neural network estimator is proposed. The design of the control scheme includes characteristic modeling, estimation for the characteristic parameters, and characteristic model-based adaptive control. The estimation method is designed based on discrete neural network aiming at solving estimation difficulties caused by fast time-variation of the parameter, and its convergence is also analyzed. Then a discrete-time sliding mode control law with a recursive form is proposed on the basis of the characteristic model, to enhance the control performance and system robustness to inevitable uncertainties. The stability analysis is conducted for the overall closed-loop system. Simulation results demonstrate the effectiveness of the proposed robust adaptive control scheme.