凹印机PID算法实现

目的论述基于PLC工业控制器的多闭环回路的PID算法实现,改进印刷机上的PID控制过程。方法针对陕西北人机组式凹版印刷机的张力控制系统,采用PLC编程实现速度和张力调节器的算法;在经典PID和数字PID算法基础上,采用试凑法对PID控制器进行参数整定,并在凹版印刷机上进行验证实验。结果速度环实验表明:在500 r/min的情况下,电机很快达到设定值,当外部扰动出现时,大约经过6 s电机重新进入稳定状态;张力环实验表明:当卷径为92~800 mm时,所整定的PID参数能够满足4个阶段收卷的不同任务要求,正常运行时系统运行速度为100~200 m/min,且系统出现外部干扰时能够很快调节摆辊位置,使其恢复到垂直位置。结论多级PID控制方式和参数整定能满足当前国产凹印机的收卷需求,但当卷径不断变化超出800 mm时,或者印刷速度大于200 m/min时,整定好的PID参数会使系统性能变坏,仍不能满足高效高速凹印机的生产任务要求,需不断改进张力控制方案。

Implementation of Control Rule PID in Gravure Printing Machine

The aim of this study was to improve the PID control system of the printer based on the implementation of PID algorithm of the multi-loop circuit of the PLC industrial controller. A multi-loop control system for tension and velocity was introduced by PLC program based on the tension control system of gravure printing machine from Shaanxi Beiren Printing Co. Ltd., then the method of trial and error was adopted to adjust parameters of the PID controller in loops based on traditional PID and digital PID principles and the verification test of the algorithm was conducted on the gravure printer. The velocity loop test showed that the motor reached the set value in a rapid manner at 500 r/min and returned to stable status in about 6 s in external disturbance. The tension ring test showed that the set PID parameters can fulfill different task requirements of winding in 4 stages when the rolling diameter was 92~800 mm. The operation velocity was 100~200 m/min at normal conditions and the roller could be quickly adjusted to vertical position when external disturbance occurred. Multistage PID control and methods of parameter setting can satisfy requirements of domestic gravure machines. However, when the rolling diameter exceeds 800 mm or the linear velocity is greater than 200 m/min, PID controller would deteriorate the system performance, which fails to fulfill the production requirements of the high-efficient and high-speed gravure printer. Therefore, continuous improvement is needed for the tension control scheme.