The Research And Design Of The Control System Of Intelligent Positioners For Hydraulic Actuator

Hydraulic control valve is a kind of important equipments in industrial process control, positioner is the major accessory of control valve, it can improve the dynamic characteristic of the valve apparently, raises the precision, speed and flexibility of control. The control system's quality of the Intelligent Positioners for Hydraulic Actuators has decided the control quality of the hydraulic control valve in very great degree.The primary work of this dissertation is the control algorithm part of the Intelligent Positioners for Hydraulic Actuators. The outline of the main hardware composition and the software frame has been summarized. Main works as follows:First of all, the structure and the work principle of the tradition valve positioners has been lucubrated in this dissertation, insufficiency has been analyzed, and the domestic and foreign development situation of the intelligent valve positioners must be tracked.Secondly, work principle of the Intelligent Positioners for Hydraulic Actuators has been elaborated. The output of the controller controls the two cylinder lumens to enter and discharge the oil by breaking and changing positions of the solenoid valve. The pressure was changed and then it makes the oil pressure of the piston's two sides no longer be equal. Thus piston position must be changed, and then actuate the valve stem to rotate. The control system of the Intelligent Positioners for Hydraulic Actuators has been overall designed, and the right types of the microprocessor chip and the peripheral equipments (such as hydraulic actuator, solenoid valve, sensor, etc.) must be chosen.Afterward, on the foundation of the ample consideration of all factors, the dynamics model of hydraulic control valve-the mathematics model of the controlled object- has been established and the transfer-function of open loop has been deduced, and the factor which causes parameters' change must be found out. And then, the virtue and shortcoming of fuzzy control and PI control should be summed up and summarized, since fuzzy control has certain complementary with PI control, therefore, the combination of fuzzy control and PI control is necessary to development. Fuzzy-PI control has not only fuzzy control's robustness, structural distinct but also the PI control's high static precision and quick dynamic response. For the Fuzzy-PI controller, the inference rule of a group of optimization has the most important influence for its performance. How to get the rule of optimization becomes one of most important works. CRI method has been used to deduce the fuzzy control rules and it was combined with PI control by the harmony gene.In the end, the application of fuzzy-PI controller in the system was detailed exposition. Intelligent Positioners for Hydraulic Actuators's overall software architecture was designed, a detailed exposition of the system signal acquisition and processing. It was combined of hardware design, then realized the design of fuzzy-PI controller.