无锡职业技术学院毕业设计说明书(外文翻译)- 2 -外文翻译PID CONTROL SYSTEMIndustrial automation has become an important indicator to measure the level of modernization of all walks of life. Meanwhile, the development has also experienced a classical control theory and control theory, the modern control theory and theory of intelligent control in three stages. Intelligent control is a classic example of fuzzy automatic washing machines. Control systems can be divided into open loop control system and closed-loop control system. Control system includes a controller, sensor, transmitter, the executing agency, I accept input and output. After the output controller output interface enforcement agency charged with a war system; Charged with volume control system, through sensors. Transmitter by input interface to the controller. Different control systems, sensor, transmitter, and the executing agency is not the same. For example, pressure control system using pressure sensors. Heating the sensor is a temperature sensor control system. At present, or PID control and intelligent controller PID controller (meters) have many, engineering products have been widely used in a wide variety of PID controller products. major companies have developed an intelligent self-tuning PID regulator (intelligent Ampre gulator), which automatically adjust the parameters of a PID controller is intelligent self-tuning or adjustment, adaptive algorithm is to be achieved. PID control is achieved using pressure, temperature, flow, liquid level control device. PID control function can be realized in the programmable logic controller (PLC). There PID control of the PC, etc. can be realized. Programmable Logic Controller (PLC) is used to achieve its PID control loop control module. and programmable logic controller (PLC) can be connected directly with ControlNet. Rockwell such as the PLC-5. PID controller can also control function, such as Rockwells Logix product lines. ControlNet it can be linked directly with the use of the network to achieve its remote control function.1, The open-loop control systemsOpen-loop control system is the object of the output ( control volume) of the controller (controller), the output will not be affected. In this control system, not dependent on the volume will be charged and sent back to form against any closed-loop. 无锡职业技术学院毕业设计说明书(外文翻译)- 3 -2,The closed-loop control system Closed-loop control system (loop control system) features of the accused The output (volume control) and the output affected by anti sent back to form a loop or more. And the positive feedback loop feedback control system, if the feedback signal and the signal systems to setting the contrary, call negative feedback (Negative Feedback), and if the same polarity, as positive feedback, closed-loop control system is used generally negative feedback, or negative feedback control system. Many examples of closed-loop control system. For example, people in a negative feedback loop control systems, sensor is the eyes, as feedback keep the human system through various amendments to finally make the right moves. If there are no eyes, no feedback loop, it became an open-loop control system. Another, when a real clothing consecutive automatic washing machine will have to wash it. Wash and can automatically after 7659, it is a closed loop control system. 3, step response Step response is a step input added to the system, the system output. Responded to enter the steady-state error is steady, the difference between the desired output and actual output. Can be used to control the performance of the system stability, prospective, quick word to describe. System stability is the stability, a system to work normally must first be stable, Step response is from the point of view of convergence; access control system is the accuracy and precision control. Usually steady-state error (Steady error) description It said output steady-state value and margin expectations; Express refers to the control of the rapid response system, Usually time to quantify the increase.4, PID control elements and features In practical projects, the most widespread application of the law to the regulator to control the ratio, integral, differential, called PID control, called PID. PID controller has been developed nearly 70-year history, with its simple structure, stability, reliability, easy to adjust and become one of the key technologies in industrial control. When the object is not fully grasp the structure and parameters, or any precise mathematical model, Other technology difficult to control, The controller 无锡职业技术学院毕业设计说明书(外文翻译)- 4 -structure and parameters have to rely on experience and on-the-spot tests to determine. Then use the most convenient PID control. When a system that we do not fully understand and object, or can not be an effective means to measure system parameters, PID control with the most suitable technology. PID control, and reality have PI PD control. PID controller is base