基于WINCC和PLC的预测PID控制仿真及实现

Simulation and realization for predictive PID control based on WINCC and PLC

针对电阻加热水冷却实验室解耦控制装置系统的强耦合性,常规的PID不能得到很好的控制效果,介绍一种基于递推最小二乘法在线辨识系统模型的广义预测、PID串级控制.通过内环PID作用将一个慢性系统变成一个动态性能比较好的控制对象,再通过外环预测控制的优化功能,增强系统的适应能力和对耦合干扰的抗干扰性.通过MATLAB仿真,验证预测PID控制算法的可行性.针对仿真不能准确描述控制对象本身的情况,又通过WINCC脚本的预测控制编程与西门子PLC中的PID算法结合,实现预测PID的串级控制.试验结果表明,预测PID较PID控制对时变控制对象具有比较好的适应能力,对耦合系统的干扰具有优于常规PID的稳定性能.

Due to the strong coupling of resistance heating water cooling laboratory decoupling control devices, the conventional PID control is difficult to have good results. This paper uses a generalized predictive PID cascade control based on changing the system model on line by using the recursive least squares method. Through the inner loop PID action, it changes a chronic system into a better control object with dynamic performance, and then enhance the system＇s adaptability and the interference immunity to the coupled interference through the outer loop predictive control optimization capabilities. Through MATLAB simulation, it verified the feasibility of predictive PID control algorithm. For the simulation that does not accurately reflect the control of the real situation, this article realizes the prediction PID cascade control by writing the predictive control program in WINCC script, and by writing the PID control algorithm in PLC and then by communicating them to achieve the predictive PID cascade control. Experimental results show that the predictive PID control has a better adaptability to the time-varying control object, comparing with PID control, and a better stable performance to the interference of the coupled system.