PID控制的意义中英文翻译资料.doc

《PID控制的意义中英文翻译资料.doc》由会员分享，可在线阅读，更多相关《PID控制的意义中英文翻译资料.doc（8页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、 The significance of PID controlThe current level of industrial automation industries to measure the level of modernization has become an important symbol. Meanwhile, the control also experienced the development of the theory of classical control theory, modern control theory and intelligent control

2、 theory of three stages. Intelligent control is a typical example of fuzzy automatic washing machine. Open-loop control system can be divided into control systems and closed-loop control system. A control system including controller, sensors, transmitters, actuators, input and output interfaces. Con

3、trollers output through the output interface, the implementing agency, added to the charged system; control system, the amount charged, through sensors, transmitters, sent to the controller through the input interface. Different control systems, sensors, transmitters, actuators are not the same. Suc

4、h as pressure control system pressure sensor to be used. Electric heating control system sensor is a temperature sensor. At present, PID control and controller or intelligent PID controller (instrument) has a lot of products have been in the engineering practice has been widely applied, there is a w

5、ide range of PID controllers, the major companies have developed PID parameter self-tuning capabilities of intelligent controller (intelligent regulator), which automatically adjusts the PID controller parameters are adjusted through the intelligent or self-correction, adaptive algorithms to achieve

6、. PID control are achieved using pressure, temperature, flow, liquid level controller, PID control can achieve programmable controller (PLC), also allows PID control of PC systems, etc. Programmable Logic Controller (PLC) is to use the closed-loop PID control module to achieve control, programmable

7、logic controller (PLC) can be connected directly with ControlNet, such as Rockwells PLC-5 and so on. PID control function also allows the controller, such as Rockwells Logix product line, which can be connected directly with ControlNet, use the network to achieve its remote control functions.1, the

8、open-loop control system Open-loop control system (open-loop control system) is charged with the object output (controlled variables) on the controller (controller) did not affect the output. In this control system, not dependent on the amount will be charged against sending it back to form any clos

9、ed loops.2, closed loop control systemClosed loop control system (closed-loop control system) is characterized by the system control object output (controlled variables) will affect the controller against the output sent back to form one or more closed loop. Closed-loop control system has positive f

10、eedback and negative feedback, if the feedback signal and system for a given value of signal contrast, is known as negative feedback (Negative Feedback), if the same polarity is called positive feedback, the general closed-loop negative feedback control systems are used , also known as negative feed

11、back control system. Many examples of closed loop control system. Such person is a negative feedback loop control system, the eye is the sensor, as feedback, the human system through constant correction to all the right moves last. If there are no eyes, no feedback loop, will become an open-loop con

12、trol system. Other cases, when a truly automatic washing machines have to continuously check whether clothes washed, and cut off the power automatically after cleaning, it is a closed loop control system.3, step response Step response is a step input (step function) added to the system, the system o

13、utputs. Steady-state error is the response of the system into steady state, the systems expected output and actual output of the difference. Control system performance can be stable, accurate, fast and three words to describe. Stability is the stability of the system (stability), a system to work pr

14、operly, first of all must be stable, from the step response appears to be that convergence; quasi-control system refers to the accuracy, control precision, usually stable state error to (Steady-state error) description, it said the system output and the expected steady-state value of the difference;

15、 faster control system response is fast, usually the rise time to quantify.4, PID control principles and characteristicsIn engineering practice, the most widely used regulator control law is proportional, integral, differential control, referred to as PID control, also known as PID regulator. PID co

16、ntroller has been developed for nearly 70 years, it is its simple structure, stable, reliable, easy to adjust and become one of the main techniques of industrial control. When the structure and parameters of the object and can not fully grasp, or lack of accurate mathematical models, control theory

17、is difficult to use other technologies, the system controller structure and parameters must rely on experience and on-site commissioning to determine, when applied PID control technique is more convenient. That is, when we do not fully understand a system and the controlled object, or can not be an

18、effective means of measurement to obtain system parameters, the most suitable PID control technology. PID control, in practice there are PI and PD control. PID controller is the error according to the system, using proportional, integral, differential calculation of the volume control to control. Pr

19、oportion (P) controlProportional control is the most simple control method. The controllers output and the input error signal proportional. When only a proportional control system output when there is steady-state error (Steady-state error). Integral (I) control In integral control, the controllers

20、output and the input error signal proportional to the integral. An automatic control system into the steady state if there is steady-state error, claimed that this control system is called a steady-state error or poor system (System with Steady-state Error). In order to eliminate steady state error,

21、 the controller must introduce the integral term. Integral term of the error depends on the time integral, as time increases, integral term will increase. Thus, even if the error is very small, integral term will increase over time to increase its promotion of the controller output increases to furt

22、her reduce the steady-state error, until zero. Therefore, the ratio of + integral (PI) controller allows the system to enter steady state of no steady state error.Differential (D) control In the differential control, the controller output and differential input error signal (ie, rate of change of er

23、ror) is proportional to. Automatic control system to overcome the errors in the adjustment process of oscillation or even instability may occur. The reason is because of greater inertia components (links), or a lag (delay) component, can inhibit the role of error, the changes always lag behind chang

24、es in the error. The solution is to change the role of inhibition of error, ahead, that is close to zero in the error and suppress the role of error should be zero. This means that the controller only the introduction of the ratio item is often not enough, the proportion of item only to enlarge the

25、role of the magnitude of the error, but now need to increase the differential item that can change the trend of forecast errors, In this way, with the proportion of + differential controller, it can advance to the role of inhibition of the control error is zero, even negative, thus avoiding the char

26、ged amount of serious overshoot. Therefore have greater inertia or lag the controlled object, proportional + derivative (PD) controller5, PID controller tuning Tuning PID controller is the core of the control system design. It is based on the characteristics of controlled process to determine the pr

27、oportion of PID controller coefficients, integral time and derivative time, the size of the. PID controller tuning are many ways to sum up, there are two categories: First, tuning the theoretical calculation. It is mainly based on the mathematical model, through theoretical calculations to determine

28、 the controller parameters. This method the calculated data may not be directly used, it must adjust and revise engineering. Second, the tuning method works, it mainly relies on engineering experience, directly in the control experiments carried out, and the method is simple, easy to master, in engi

29、neering practice is widely used. PID controller parameter tuning method works, mainly the critical ratio, reaction curve and attenuation. Three methods have their own characteristics, their common points are the experiment, and then follow the empirical formula works on the controller parameter tuni

30、ng. But no matter which method used by the controller parameters are needed in the actual operation of the final adjustment and improvement. Now commonly used is the critical ratio method. PID controller using the method parameter setting of the following steps: (1) first pre-select a short enough s

31、ampling period of the system to work; (2) by adding proportional control only part until the system appears critical step response input oscillation Note the amplification factor and the proportion of time critical oscillation period; (3) a certain degree of control in the formula be adopted under t

32、he PID controller parametersPID控制的意义目前工业自动化水平已成为衡量各行各业现代化水平的一个重要标志。同时，控制理论的发展也经历了古典控制理论、现代控制理论和智能控制理论三个阶段。智能控制的典型实例是模糊全自动洗衣机等。自动控制系统可分为开环控制系统和闭环控制系统。一个控制系统包括控制器、传感器、变送器、执行机构、输入输出接口。控制器的输出经过输出接口、执行机构，加到被控系统上；控制系统的被控量，经过传感器，变送器，通过输入接口送到控制器。不同的控制系统，其传感器、变送器、执行机构是不一样的。比如压力控制系统要采用压力传感器。电加热控制系统的传感器是温度传感器。

33、目前，PID控制及其控制器或智能PID控制器（仪表）已经很多，产品已在工程实际中得到了广泛的应用，有各种各样的PID控制器产品，各大公司均开发了具有PID参数自整定功能的智能调节器，其中PID控制器参数的自动调整是通过智能化调整或自校正、自适应算法来实现。有利用PID控制实现的压力、温度、流量、液位控制器，能实现PID控制功能的可编程控制器(PLC)，还有可实现PID控制的PC系统等等。 可编程控制器(PLC) 是利用其闭环控制模块来实现PID控制，而可编程控制器可以直接与ControlNet相连，如Rockwell的PLC-5等。还有可以实现 PID控制功能的控制器，如Rockwell 的L

34、ogix产品系列，它可以直接与ControlNet相连，利用网络来实现其远程控制功能。1、开环控制系统开环控制系统是指被控对象的输出(被控制量)对控制器的输出没有影响。在这种控制系统中，不依赖将被控量反送回来以形成任何闭环回路。2、闭环控制系统闭环控制系统的特点是系统被控对象的输出(被控制量)会反送回来影响控制器的输出，形成一个或多个闭环。闭环控制系统有正反馈和负反馈，若反馈信号与系统给定值信号相反，则称为负反馈，若极性相同，则称为正反馈，一般闭环控制系统均采用负反馈，又称负反馈控制系统。闭环控制系统的例子很多。比如人就是一个具有负反馈的闭环控制系统，眼睛便是传感器，充当反馈，人体系统能通过不

35、断的修正最后作出各种正确的动作。如果没有眼睛，就没有了反馈回路，也就成了一个开环控制系统。另例，当一台真正的全自动洗衣机具有能连续检查衣物是否洗净，并在洗净之后能自动切断电源，它就是一个闭环控制系统。3、阶跃响应阶跃响应是指将一个阶跃输入加到系统上时，系统的输出。稳态误差是指系统的响应进入稳态后，系统的期望输出与实际输出之差。控制系统的性能可以用稳、准、快三个字来描述。稳是指系统的稳定性，一个系统要能正常工作，首先必须是稳定的，从阶跃响应上看应该是收敛的；准是指控制系统的准确性、控制精度，通常用稳态误差来描述，它表示系统输出稳态值与期望值之差；快是指控制系统响应的快速性，通常用上升时间来定量描

36、述。4、PID控制的原理和特点在工程实际中，应用最为广泛的调节器控制规律为比例、积分、微分控制，简称PID控制，又称PID调节。PID控制器问世至今已有近70年历史，它以其结构简单、稳定性好、工作可靠、调整方便而成为工业控制的主要技术之一。当被控对象的结构和参数不能完全掌握，或得不到精确的数学模型时，控制理论的其它技术难以采用时，系统控制器的结构和参数必须依靠经验和现场调试来确定，这时应用PID控制技术最为方便。即当我们不完全了解一个系统和被控对象，或不能通过有效的测量手段来获得系统参数时，最适合用PID控制技术。PID控制，实际中也有PI和PD控制。PID控制器就是根据系统的误差，利用比例、

37、积分、微分计算出控制量进行控制的。比例（P）控制比例控制是一种最简单的控制方式。其控制器的输出与输入误差信号成比例关系。当仅有比例控制时系统输出存在稳态误差。积分（I）控制在积分控制中，控制器的输出与输入误差信号的积分成正比关系。对一个自动控制系统，如果在进入稳态后存在稳态误差，则称这个控制系统是有稳态误差的或简称有差系统。为了消除稳态误差，在控制器中必须引入“积分项”。积分项对误差取决于时间的积分，随着时间的增加，积分项会增大。这样，即便误差很小，积分项也会随着时间的增加而加大，它推动控制器的输出增大使稳态误差进一步减小，直到等于零。因此，比例+积分(PI)控制器，可以使系统在进入稳态后无稳

38、态误差。微分（D）控制在微分控制中，控制器的输出与输入误差信号的微分（即误差的变化率）成正比关系。自动控制系统在克服误差的调节过程中可能会出现振荡甚至失稳。其原因是由于存在有较大惯性组件（环节）或有滞后组件，具有抑制误差的作用，其变化总是落后于误差的变化。解决的办法是使抑制误差的作用的变化“超前”，即在误差接近零时，抑制误差的作用就应该是零。这就是说，在控制器中仅引入 “比例”项往往是不够的，比例项的作用仅是放大误差的幅值，而目前需要增加的是“微分项”，它能预测误差变化的趋势，这样，具有比例+微分的控制器，就能够提前使抑制误差的控制作用等于零，甚至为负值，从而避免了被控量的严重超调。所以对有较

39、大惯性或滞后的被控对象，比例+微分(PD)控制器能改善系统在调节过程中的动态特性。5、PID控制器的参数整定PID控制器的参数整定是控制系统设计的核心内容。它是根据被控过程的特性确定PID控制器的比例系数、积分时间和微分时间的大小。PID控制器参数整定的方法很多，概括起来有两大类：一是理论计算整定法。它主要是依据系统的数学模型，经过理论计算确定控制器参数。这种方法所得到的计算数据未必可以直接用，还必须通过工程实际进行调整和修改。二是工程整定方法，它主要依赖工程经验，直接在控制系统的试验中进行，且方法简单、易于掌握，在工程实际中被广泛采用。PID控制器参数的工程整定方法，主要有临界比例法、反应曲线法和衰减法。三种方法各有其特点，其共同点都是通过试验，然后按照工程经验公式对控制器参数进行整定。但无论采用哪一种方法所得到的控制器参数，都需要在实际运行中进行最后调整与完善。现在一般采用的是临界比例法。利用该方法进行 PID控制器参数的整定步骤如下：(1)首先预选择一个足够短的采样周期让系统工作；(2)仅加入比例控制环节，直到系统对输入的阶跃响应出现临界振荡，记下这时的比例放大系数和临界振荡周期；(3)在一定的控制度下通过公式计算得到PID控制器的参数。8