基于干扰观测器的不确定非线性系统终端滑模控制器设计

Disturbance observer-based terminal sliding mode controller design for uncertain nonlinear systems

考虑系统遭受复合干扰影响,针对一类不确定非线性系统的控制问题展开研究.首先,提出一种n阶超螺旋干扰观测器,对系统干扰进行估计;然后,结合系统的结构特点和滑模控制理论构造积分滑模面,并与二阶快速终端滑模控制理论相结合,设计基于干扰观测器的滑模控制器,通过引入反曲函数降低抖振,利用Lyapunov理论证明闭环系统的稳定性;最后,将该方法应用到磁悬浮系统的稳定性控制并进行仿真实验,结果表明了所提出方法的有效性.

For a class of uncertain nonlinear systems,the control problem under the condition that every order of the systems is affected by unknown disturbance is investigated.Firstly,a n-orders super twisting disturbance observer is introduced,which estimates the disturbances of the systems.Then,based on the structure of the systems and the sliding mode control technique,a sliding surface with integral function is designed.Combineing with the second order fast terminal sliding mode control theory,a sliding mode controller based on the proposed disturbance observer is presented.In order to alleviate the chattering caused by the sign function,the sigmoid function is employed.And the stability of the closed-loop system is proved by the Lyapunov theory.Finally,the method is applied to the simulaton for controlling the magnetic levitation system,and the results show the effectiveness of the proposed method.