一种IAE指标触发的继电反馈PID参数自校正方法

A Relay Automatic Tuning of PID Control Systems Triggered by IAE Index

摘要:

针对实际工业过程中固定PID参数不能适应系统特征变化的问题,提出了一种在线控制器参数自动校正方法。首先,以内模控制为基础,由系统工作数据估计得到设定值阶跃变化下系统可获得的最优累积绝对误差值(IAE),并以此建立评价当前控制器优劣的性能指标。若性能不满足要求,则触发PID参数校正算法工作,通过引入继电反馈环节使控制回路振荡,获得控制系统临界信息,再根据改进的Z-N规则计算新的PID控制器参数。最后,分别用仿真和实际液位控制系统验证所提方法的有效性。

Abstract:

A new on-line automatic tuning method for PID controllers is presented to solve the problem that PID parameters can not adapt to the change of system characteristics. Firstly, on basis of the internal model control (IMC), the optimal integrated absolute error (IAE) is estimated by the operating data of control system when the set values are changing. Then performance index is established to evaluate the controller. If the performance does not meet the requirements, the PID tuning algorithm is triggered. The critical information can be identified from the oscillating curve which is caused by the relay. Then, the optimized PID parameters are obtained according to the improved Z-N rules. Finally, the effectiveness of the proposed method is verified by a simulation example and an actual level control system.