摘要：在工业生产过程中，经常由于物料或能量的传输带来时间延迟的问题，即被控对象具有不同程度的纯滞后，不能及时反映系统所受的扰动,不少工业对象存在着纯滞后时间。这种纯滞后时间或者是由于物料或能量传输过程中所引起的。或者是由于对象中多容积所引起的，或者是高阶对象低阶近似后所形成的等效滞后。迟延对象的控制一直是控制领域研究的焦点问题。对于大纯滞后系统, 用单纯PID 算法效果较差, 严重时甚至会引起振荡，在PID算法基础上引入史密斯补偿可以取得良好效果。史密斯于1957 年提出了一种预估补偿控制算法。它针对纯滞后系统中闭环特征方程含有纯滞后项，在PID反馈控制基础上，引入了一个预估补偿环节，从而使闭环特征方程不含纯滞后项，提高了控制质量。同时，PLC稳定可靠，编程方便，非常适合应用于纯滞后系统。因此本文提出一种采用PLC 来实现史密斯预估补偿的新方法。采用史密斯预估补偿的方法， 比用常规PID 超调量显著减小，提高了系统的稳定性，控制效果令人满意。本次设计完成了史密斯预估PLC控制模块搭建、编程。最后还使用Matlab软件对史密斯预估控制进行仿真，得出曲线图。7817
关键词：  史密斯预估控制；大纯滞后；PLC编程；Matlab仿真
Smith predictive control based on PLC
Abstract： In the process of industrial production, often due to transmission of material or energy to bring the problem of time delay, it is said the plant have varying degrees of time delay. Many industrial objects exist pure lag time. This lag time is caused by material or energy transfer process. It is caused by objects in the volume, or it is equivalent to higher-order objects formed by low order approximation of the lag. Control of time delay system is always the focus problem in the field of control.For large time delay system, with simple PID algorithm effect is poor, serious and even cause oscillation, the introduction of Smith compensation based on the PID algorithm can achieve good results. Smith in 1957 proposed a predictive compensation control algorithm. Aiming at the system closed-loop characteristic equation containing pure lag time delay in the feedback control, based on PID, a predictive compensation is introduced, so that the closed-loop characteristic equation does not contain pure time-delay terms, improved quality control.At the same time, the PLC is stable and reliable, convenient programming, is very suitable for the system with pure time delay. This paper presents a new method to implement the Smith predictive compensation based on PLC. The predictive compensation method of Smith, significantly reduced compared with the conventional PID, the overshoot, increase the stability of the system, satisfactory control effect. This design is needed to complete the Smith predictive PLC control module structures, programming. Finally, also need to use the Matlab software to simulate the Smith predictive control, draw graphs.
Keywords：Smith predictive control; large delay; PLC programming; Matlab simulation
目录
1 绪论    1
1.1 引言    1
1.2 国内外温度控制系统的发展    2
2 PID控制    3
2.1 PID控制原理    3
2.2 PID参数整定方法    4
2.3 PID控制的不足    5
3 史密斯预估控制    6
3.1 本文选用对象说明    6
3.2 史密斯预估控制原理    6
4 计算机中实现史密斯预估控制    9
4.1 数字PID 控制器    9
4.2史密斯预估器    10
5 基于PLC的锅炉温度史密斯预估控制    14
5.1 PLC基础    14
5.2 PLC型号的选择    15 基于PLC的锅炉温度史密斯预估控制仿真:http://www.youerw.com/zidonghua/lunwen_5909.html