Design Of Constant Pressure Control Algorithm And Development Of System For FRP Pipe Life Detection Test

FRP pipe is a multi-layer high-performance flexible composite pipe,which has the outstanding advantages of strong pressure resistance,good corrosion resistance,light weight,high safety factor,etc.Therefore,it is widely used in scientific research and production enterprises.In order to ensure product quality,each pipe must undergo a strict life test before leaving the factory.Due to the smaller elastic modulus of glass fiber reinforced plastics,the pressure of the system caused by external interference fluctuates greatly,which makes the detection system highly nonlinear and time-varying.In view of the fact that the detection accuracy of the detection test system based on PID control is low and the quality detection error is large,this paper takes a certain type of FRP pipe life detection test as the research object,a constant pressure control algorithm was designed and an intelligent monitoring system was developed to improve the pressure control accuracy of the system.The specific research includes the following aspects:(1)A mathematical model built for the life detection system of FRP pipes.The frequency conversion speed regulation technology and the energy conservation principle was analyzed.Combined with the working principle of the three-phase asynchronous motor,the approximate transfer function of the motor in the pressure regulation and speed regulation process was deduced by the micro-bias linearization method,and the transfer function of other key components in the constant pressure control system and the water injection pipe network were established in turn.Finally,the mathematical model of the entire control system was derived.(2)A constant pressure control algorithm was designed for the FRP life testing system.Due to the poor self-adaptability of the current experimental system based on traditional PID control,it cannot meet the steady-state error accuracy requirements of the test requirements.The model reference adaptive control algorithm was designed based on Popov hyper stability theory for frequency constant pressure detection system.The simulation model was established to verify the effectiveness of the algorithm.Through field tests,it is concluded that the adaptive control algorithm can ensure that the system’s steady-state error is controlled within ±0.03 Mpa,which fully meets the control accuracy requirements of the test.(3)The communication system of the life test of glass steel pipe was studied.In combination with optical fiber communication technology and ring network redundancy technology,a fiber ring-type redundant Ethernet based on TCP/IP protocol is designed,and a heartbeat signal detection program was written.In order to facilitate the storage and management of large amounts of data,the data is transmitted to the access database through the ODBC interface,at the same time based on the WEB publishing function of the Kingview to achieve remote monitoring.(4)An intelligent monitoring system for the life detection system of FRP pipes was developed.In combination with Kingview configuration software and programmable logic controller(PLC),a distributed intelligent monitoring system was developed,including the preparation of the lower computer program,the development of the host computer monitoring interface,the design of the communication system,and the construction of the field test platform.