模糊自整定PID液体混合系统

盛燕,邹轩

(上海理工大学 光电信息与计算机工程学院,上海200093)

摘要为解决实际液体混合装置控制方法单一、不能连续进行液体混合和精确度较低等问题,采用PID控制。传统PID控制参数固定,难以适应系统状态改变后的要求,且控制系统超调量大、调节时间长。模糊自整定PID控制方式,以流量比为设定值,能在线实时调整PID参数,消除扰动,控制稳定。应用PLC实现模糊自整定PID控制,结合简单输入输出控制,具有连续性与间断性相结合、操作简单、鲁棒性好等优点。仿真结果表明,超调量比传统PID减少36%,过渡时间减少约3 s,从而提高了生产效率,降低了人工成本。

关键词模糊自整定PID;流量控制;Simulink

收稿日期:2015-04-17

作者简介:盛燕(1990—),女,硕士研究生。研究方向:电了系统运行及其自动化。E-mail:cathysuan@163.com

doi:10.16180/j.cnki.issn1007-7820.2015.12.036

中图分类号TM571文献标识码A

Liquid Mixing System Based on Fuzzy Self-tuning PID

SHENG Yan,ZOU Xuan

(School of Optical-Electrical and Computer Engineering,University of Shanghai for

Science and Technology,Shanghai 200093,China)

AbstractPID control theory is utilized to deal with the problems of simple input/output control,discontinuous liquid mixing and poor accuracy.There are some problems in traditional PID control,such as troubles in adjustment after the state change of the system,large overshoot and long setting time.In combination with the fuzzy theory,flow valves are adjusted and all disturbances in the system will be eliminated to achieve the accurate mixture.PLC realizes the fuzzy self tuning PID and manages with input/output control.It has advantages of continuous and discontinuous operation,less overshoot and good robustness.Its overshot is 36% less than that of the traditional PID.Moreover,the setting time is reduced by 3 seconds with higher production efficiency and lower labour cost.

Keywordsfuzzy self-tuning PID;flow control;Simulink

传统液体混合装置中,控制系统常采用PLC、单片机等作为核心。其工作方式为:启动装置,注入液体1。当液体1达到指定液位1,则关闭液体1阀门,注入液体2直至达到指定液位2[1]。此种工作方式只能满足小型生产,效率低下。为提高液体混合效率,可采用在线监测液体流量,使用相对成熟的PID作为基本控制方法。但系统中,参数整定较为复杂,导致应用过程中操作不便,且PID的固定参数难以适应系统状态改变时的要求[2]。模糊自适应PID控制器在液体混合装置中的应用,解决了多种液体连续混合的问题,并节约了成本。同时,由于液位传感器的存在,兼顾了一定体积混合液体的生产。……