Research On Pressure Control Technology Of Vacuum System With High Leakage Rate

In the development of vacuum test equipment,leakage problems are unavoidable.In particular,large leakage problems caused by test structures with special functions seriously affect the performance of the vacuum system.Therefore,it has important research significance and engineering practical value for the sealing design of large leakage rate of vacuum system and the research of vacuum system pressure control technology.In this paper,according to the development requirements of vacuum test equipment,through research on the large leakage rate of the seal structure and the air pressure control technology,the development of a low-pressure air box is completed.The specific work is as follows:1.The leakage characteristics of the large leak rate vacuum system and the non-linear,pure hysteresis and pure dynamic characteristics during the pressure control process were analyzed.The design of the special seal structure was completed;Vacuum pumping group pumping speed calculation and vacuum pump selection were performed,and the vacuum system design with large leak rate was completed.2.For the previously selected unit,calculate the pressure change function over time when different vacuum pumps are running;Through the study of the seal structure,the leakage problem caused by the wire seal was analyzed;Based on the static boost method,the analysis of the entire vacuum system's air leakage is completed;Combined with pumping model and system leakage model,the pumping and deflation model of the entire high leakage rate vacuum system was obtained,which provided a basis for the design of the subsequent pressure controller.3.A feasible multi-mode control scheme was proposed for the problem of large leakage rate,and the controller design and Simulink simulation were completed.Simulation analysis4.results show that for high leakage rate vacuum systems,compared to pure PID control or pure Bang-Bang control,the dual-mode control method using Bang-Bang control combined with fuzzy control has higher control accuracy and faster response time.5.Based on the developed vacuum test chamber,the mathematical model of the pumping gas and the effect of the air pressure controller were tested and verified.The experimental results show that the mathematical model of the pumping gas is accurate and the control effect of the air pressure controller is good,and it provides a reference for the similar large leak rate vacuum pressure control problems.In summary,through analyzing and studying the large leak rate vacuum system,this paper solves the problem of difficult modeling of large leak rate vacuum system and proposes a reasonable pressure control scheme,and provides a basis for the development of large leak rate vacuum system.