Research And Development Of The Five-axis Parallel Friction Welding Machine CNC System

Burgeoning friction stir welding technology has a unique advantage in the welding of aluminum alloy. The advantages of Parallel machine tools, high stiffness and high flexibility,solve the problem that friction stir welding technology needs big upset force and forward resistance force. CNC system is the control core of the parallel friction welding machine, so the development of CNC system has become an important part of the development of the machine. Parallel machine tools demands that CNC system open. PA system allows users to go deep into CNC module of the system, and develop function that user needs because of its architecture. This study is to develop a CNC system with the function that the parallel friction welding machine requires based on PA system.In this paper functional requirements of CNC system is analyzed on the basis of user’s requirements,then function planning is carried through. The whole framework of the CNC system is designed and the overall scheme is planned on the basis of the analysis of PA system hardware and software architecture.The function for supporting 3PRS parallel mechanism is developed. First, the structure of 3PRS parallel kinematic head is analyzed, and motion parameter equations of major moving parts is deducted on the basis of it. Then motion control algorithm on the motion nonlinear of parallel machine movements is written, and embedded into the CNC system using Compile Cycles technolodgy provided by PA system.Online simulation module of the CNC system is developed. First of all, the interface layout of PA system is changed by modifying HMI configuration files of the system to add of hardkeys and softkeys, and the response function to softkeys is completed with Extensible Markup Language (XML). Then ActiveX control is developed with Visual C++ to read the 3DS file of machine model while read machine position data from the CNC and PLC, then drawing machine simulation models, motion simulation and the conversion of viewing angle are done by graphics programming interface OpenGL, finally registry ActiveX control which is compiled successfully to the Windows system.Finally, other functions that the CNC system requires are achieved in PA system.Measurement function is designed for deformation characteristics of large and thin-walled welded workpiece, measuring by means of adding lateral movement command in NC code and using laser measuring head, then reading the measurement data by fast digital I/O interface to obtain weld head location. The precision calibration algorithm is written to complete the precision calibration function by analyzing the factors which affect the accuracy of the machine. While switching series-parallel function, resetting in situ function, exiting and continuing while tool is broken function and operating in virtual or actual axis mode function are completed.