基于继电反馈的被控对象特征参数研究

Characteristic Parameters of Controlled Object Based on Relay Feedback

为了更好地整定PID控制器,需要获取被控对象准确的模型信息,由于继电反馈时Z-N整定规则的计算精度低且工程中被控对象特征参数不确定,无法采用先进的控制方案对系统进行准确控制。基于继电反馈对PID控制器参数自整定方法进行研究,针对近似为一阶惯性纯滞后环节的工业对象进行仿真分析。通过继电反馈获取系统临界信息,推理出临界信息与模型参数的函数关系,最终求出特征参数值。试验结果表明,该函数关系能以较低的误差辨识出惯性时间和滞后时间,为PID控制器的设计提供定量参考。

In order to better tune the PID controller,it is necessary to obtain accurate model information of the controlled object.Due to the low calculation accuracy of Z-N setting rules in relay feedback and uncertain characteristic parameters of the controlled object in engineering,it is impossible to use advanced control scheme to accurately control the system.The PID controller parameter self-tuning method based on relay feedback is proposed,and the simulation analysis is carried out for the industrial object which is approximately the first order inertial pure lag link.The critical information of the system is obtained through relay feedback.Then the function relationship between the critical information and the model parameters is deduced.Finally,the characteristic parameters are calculated.The experimental results prove that the function relation can identify the inertia time and the lag time in condition of low error,which provides a quantitative reference for the design of PID controller.