高阶控制系统降阶处理中的增益变化研究

Research on Gain Change during Order Reduction of High Order Control System

我们在分析和设计高阶控制系统时,常常需要根据主导极点对系统进行降阶处理。本文举例分析了高阶控制系统在恒根轨迹增益和恒开环增益条件下的不同降阶结果,并在Matlab环境下对比研究了降阶前后系统的单位阶跃响应。结果表明:在对高阶系统降阶处理过程中,根轨迹增益会发生相应变化,欲使系统降阶前后具有满意的暂态和稳定性能,降阶时应将系统传递函数统一整理成时间常数形式。

During analysis and design process of high order control system, dominant poles are often used to reduce high order control system to low order system. In this paper, two different order reduction results of high order sys- tem are illustrated under constant root locus gain and open-loop gain conditions; unit step responses of the system before and after order reduction are compared and studied in Matlab environment. The results show that root locus gain changes correspondingly during order reduction process, in order to make the system have satisfactory transient and steady performance before and after order reduction, the transfer function should be unified into time constant form.