Control System Design For Thread Of High Pressure FRP Pipe

Due to the advantages of light quality, high strength, corrosion resistance and decent hydraulic properties, FRP is widely used in many areas such as transporting corrosion medium in petrochemical industry, transporting oil and gas, water conservancy, etc.Nowadays, the connection of FRP pipe usually adopts the methods of mechanical, adhesive bonding and thread connection. The mechanical method and the adhesive bonding method have many different disadvantages, so the thread connection method is generally adopted in many countries. So the quality and strength of thread are important factors affect the connection of pipeline. For small diameter FRP pipe, circular mould and grinding process are usually adopted; for big diameter FRP pipe, only grinding process can be used.In this paper, according to the demand of the thread making and the requirement of practical production, the process parameters and control parameters fit for the thread grinding system are designed. In addition, aiming at the characteristic of the running of thread grinding machine, the trigonometric function calculation method is adopted to the system after analysis and comparison. Meanwhile, the servo system three-loop control mathematical model with friction is established, and the friction dynamic simulation of the motion characteristics of speed loop and position loop is performed; the system performance is tested through building the experimental platform. Based on analysis, the hardware and software of the system is entirely designed. The open master-slave control system as the core of industrial control PC and PAMC2A-PC104 motion controller which combined with the original machine is put forward. In this thread grinding system, the PAMC embedded motion controller is responsible for the equipment movement and dispatching movement program; the PC make communication in real-time through the serial port RS232, which uses the PComm32 communication function library provided by the Delta Tau Corporation, it is responsible for monitoring the running state of equipments and supervising the process document.In the meantime of realizing the external thread making of big diameter high pressure FRP pipe, this system integrates the two process steps of thread machining and cone grinding, which speeds up the progress and improves the efficiency. Currently, the function and the technical index of the pipeline thread grinding machine numerical control system totally meet the qualification. The system runs well during a long-time operation, and can satisfy the requirement of practical machining.