基于干扰观测器的非线性不确定系统自适应滑模控制

本文研究了一类基于非线性干扰观测器的多输入多输出非线性不确定系统的边界层自适应滑模控制方法并应用于近空间飞行器高精度姿态控制.考虑系统存在不确定性和外部干扰上界未知的情况,设计了基于干扰观测器的边界层自适应滑模控制器,以消除传统滑模控制中的"抖振"现象,使跟踪误差趋近于零.同时,利用李雅普洛夫方法严格证明了闭环系统的稳定性.最后将所研究的自适应滑模控制方法,应用于某近空间飞行器的姿态控制中,仿真结果表明在不确定性和外部干扰作用下能保证姿态控制的稳定性,对参数不确定具有较好的鲁棒性.

Adaptive sliding mode control for nonlinear uncertain systems based on disturbance observer

A boundary layer adaptive sliding-mode controller is developed for a class of multi-input and multi-output (MIMO) nonlinear uncertain systems based on the nonlinear disturbance observer (NDO). The developed adaptive sliding- mode controller has been applied to the high-precision attitude control for near space vehicles. Considering the system uncertainty and the unknown upper bound of the external disturbance, we design the boundary layer adaptive sliding-mode control scheme for eliminating the chattering phenomenon appeared in the traditional sliding-mode control and making the tracking error to approach zero. The rigorous stability of the closed-loop system is proved by using the Lyapunov method. Finally, simulation results demonstrate that the proposed control scheme can achieve good control performances for the attitude control of the near space vehicle under the unknown disturbance and the system uncertainty.