Research On The Control Technology Of A Direct-drived Gas Regulating Valve

With the development of industrial technology, fast-response and high-precision pneumatic servo control technology is required urgently. Due to the constraint of the drive device’abilities, the research of single-stage high-power electric-pneumatic servo valves is rare currently. Thus, this paper take a high pressure and high flow gas regulating valve as the research object, which demands of fast response and high positioning accuracy. A scheme direct-drived by the moving coil electromagnetic linear actuator is proposed and the performances with different control methods by simulation and prototype testing is studied. The main content is followed as:1. Direct-drived gas regulating valve system program is designed and its model is bulit. According to the demand of fast-response and high degree of accuracy, a scheme that the gas regulating valve direct-drived by the moving coil electromagnetic linear actuator is proposed and its control system is designed. The working principle of the gas regulating valve system is analyzed, the system is decoupled and simplified.Then, the model of the system is built to prepare for the study of the control methods.2. The testing system of direct-drived gas regulating valve system is developed. As an important precondition of researching control methods, the testing system which consists of electromagnetic linear actuator, artificial load, controler is developed.3. The segment control method combing inverse system control and PI control method for the gas regulating valve system is studied. First, considering many advantages of the fast response, the inverse system control is used to control the gas regulating valve’s moving, however large steady-state error is found during simulation. Then, the segment control method combing with inverse system control and PI control is proposed. The inverse system control is used to meet the requirement of fast response, and PI control is used to meet the requirement of positional accuracy. The performance of the segment control method is verified by simulation and prototype testing. However, because the segment control structure is unstable, a large disturbance may cause overshoot.4. The sliding mode control for the gas regulating valve system is studied. In order to enhance the anti-disturbance ability and robustness of the system, the reaching rate sliding mode is proposed, but this control method has overshoot because it has no robustness to the external load disturbance in the reaching mode. Then, a global sliding mode control method is proposed, which eliminates the reaching mode. But in order to prevent the large load disturbance, the system control input "chattering" is still large. Therefore, the sliding mode control based on extended state observer is proposed, which the total disturbance of the system is observed by the extended state observer and compensated in the sliding mode control. Not only the control input is smoothed, but also the anti-disturbance ability and robustness of the system is enhanced.The preliminary pneumatic test has been carried on the studied direct-drived gas regulating valve system, which achieved good effect by reaching the performance index of high-response and high positioning accuracy.