关于滞后不确定系统的变结构控制与仿真

Variable Structure Control for Uncertain System with Time-delay

研究变结构优化控制,对于含有状态滞后和输入滞后的不确定离散时间系统,采用传统的变结构控制器设计方法,很难解决控制输入滞后对系统性能造成的影响,并使系统抖振和控制输入切换幅度过大的问题,控制效果不理想。为解决上述问题,对状态滞后和输入滞后相同的一类不确定离散时间,进行变结构控制器的设计。根据系统滑模面可达条件,用系统模型不确定项进行等效替换处理,提出改进的变结构趋近律。利用趋近律设计的控制器克服了系统抖振和控制输入切换幅度过大的问题。仿真结果表明,控制器不仅能够保证系统具有良好的稳态和动态性能,同时动态过程中控制量的切换幅度也可以控制在要求范围内。

It is difficult to get a good control quality of a system with both state time-delay and input time-delay using traditional variable structure control method.The bad influences,including system chattering and the large scale of the controller＇s output,are hard to handle by traditional method of variable structure control method,and the input time-delay is difficult to deal with.To solve this problem,the variable structure control problem is studied for discrete-time system which contains uncertainties with the same time-delay of state and input.An improved discrete reaching law is presented for the controller design of this kind of system.The parameters are selected based on reaching condition.The control law is properly improved considering the state and input time-delay.Meanwhile it also solves the problems of the system chattering and the large scale of the controller＇s output.The simulation results illustrate that the designed controller with the improved reaching law can not only ensure good static and dynamic performances,but also confine the output of the controller into certain accredited boundary.