Study On The Control System Of The Gas Flow Standard Facility

Gas flow standard facilities are essential to test gas flow sensors,meters and other devices.With the industrial upgrading and development relying on the internet,the internet and informatization of gas flow standard facilitis and the high efficiency of control need to be studied accordingly.The critical flow sonic nozzles gas flow standard facility with medium-pressure and closed-loop pipelines at Tianjin University Flow Lab is used for this study.The following research work was completed.Firstly,based on the B/S architecture,the network control system of the flow standard facility was developed.The system includes hardware control system,data management system,user management system,real-time interactive system and operation safety guarantee system,which provides internet operation support for the network monitoring management of flowmeter calibration.Secondly,aiming at the process of flowmeter calibration,the model of flowmeter calibration network is studied.Based on the operation data of flow standard facility,a unique multiple feedback and interaction structure of the calibration network is established with this model.Different data content is divided into different topic by data management system.The access control of user management system is designed based on observer pattern,and users can subscribe topics flexibly.The real-time internet monitoring of the flowmeter calibration network is realized through the browser and server full-duplex communication capability of WebSocket protocol.Thirdly,aiming at the problem of slow pressure regulation and disturbance recovery of the closed-loop gas flow standard facility,the system identification modeling of the facility is carried out,and a pressure control system based on the linear Active Disturbance Rejection Control(ADRC)strategy is designed and realized.The robustness,control speed and disturbance rejection ability of ADRC are compared with PID through simulation and gas flow experiments.The results show that,compared with PID,ADRC has a shorter settling time,stronger disturbance rejecting capability and more robust performance in a wide range of pressure.The ADRC algorithm can improve the pressure control performance of gas flow standard facility.