一种新的实用PI控制闭环辨识方法

A new practical method for closed-loop identification with PI control

中文关键词  闭环辨识  PI控制  二阶加时滞  比较系数法

英文关键词  closed-loop identification  proportional-integral control  second-order-plus-dead-time  coefficient-comparison

中文摘要

      对于有PI控制器的闭环系统, 提出一种辨识方法, 可以在闭环系统运转下得到控制对象的开环传递函数. 首先, 根据闭环系统的衰减振荡曲线, 近似地求出闭环控制系统的二阶加时滞(SOPDT)闭环传递函数. 然后, 用方框图等效法, 在所得的闭环传递函数中将PI控制器分离出去; 再通过比较系数就得到对象的开环传递函数. 数字仿真和辨识实验表明此法有很好的辨识精度, 计算量小且非常易于在线实现, 具有比较重要的现实意义.

英文摘要

      For a closed-loop system with a PI controller, we propose a method to identify the transfer function of the controlled object. From the under-damped-response of the closed-loop system, we approximate the closed-loop system by a second-order-plus-dead-time(SOPDT) transfer function. The transfer function of the PI controller is then removed from the approximate closed-loop transfer function. From the remaining transfer function, the open-loop transfer function of the controlled object is determined through a coefficient-comparison process. Both the simulations and the control experiments on a pilot-equipment show advantages of the proposed method, such as the high identification-accuracy, the low computational complexity and the easy online implementation, thus demonstrating its application potential.