不确定非线性系统的自适应反演终端滑模控制

Adaptive backstepping-based terminal-sliding-mode control for uncertain nonlinear systems

针对一类参数严格反馈型不确定非线性系统,本文提出一种自适应反演终端滑模控制方法.反演控制的前n?1步结合自适应律估计系统的未知参数,第n步采用非奇异终端滑模,使系统最后一个状态有限时间内收敛.利用微分估计器获得误差系统状态的导数,并设计了高阶滑模控制律,去除控制抖振,使系统对于匹配和非匹配不确定性均具有鲁棒性.同自适应反演线性滑模方法相比,所提方法提高了系统的收敛速度和稳态跟踪精度,并且控制信号更加平滑.仿真结果验证了该方法的有效性。

An adaptive backstepping-based terminal-sliding-mode control method is proposed for a class of uncertain nonlinear systems in parametric-strict feedback form. The adaptive control law is combined with the first n - 1 steps of the backstepping method to estimate the unknown parameters of the system. In the n-th step, a nonsingular terminalsliding-mode is then utilized to drive the last state of the system to converge in a finite period of time. Furthermore, the derivative estimator is used to obtain the derivatives of the states of the error system; and the high-order sliding-mode- control law is designed to eliminate the chattering and to make the system robust to both the matched and the mismatched uncertainties. Compared to the adaptive backstepping-based linear sliding-mode-control method, the proposed method improves the convergence rate and the steady-state tracking accuracy of the system, and makes the control signal smoother. Finally, the simulation results are presented to validate the method.