| With the proposal and extension of China’s Industry 4.0 concept, the progress of advanced equipment manufacturing is facing unprecedented opportunities and challenges. As important propulsion device of ship equipment, the processing quality and efficiency of marine propeller represents the driving force for the development of deep sea technology in China. At present, there are several common problems of propeller processing such as low efficiency of one side machining, the difficulty of clamping and positioning, the machining-vibration and the poor openness and stability of the control system. In order to solve above problems, a method of double-cutter and double-surface machining technology based on the serial-parallel mechanism tool with the core technology of CNC system development was introduced by the research group. A new idea of using the soft PA CNC system as motion controller of the XYZ-3RPS six-axis horizontal type machine tool was put forward in this paper, and then the control module was developed based on the system, laying the theoretical and technical foundation for the double-surface machining of propeller, which is of great significance to further improvement of the processing method of marine propeller.The motion control algorithm of serial-parallel machine tool was studied in this paper. Through analyzing the structure of the six-axis horizontal serial-parallel machine tool, the mathematical model of the machine tool, the description of the position and orientation of moving platform with the constraint equations between device coordinate system were established. The 6 drive length inverse solution algorithm was obtained through parameter decoupling of the serial-parallel mechanism. And then the validity of algorithm was verified by united simulation based on MATLAB and ADAMS.The structure of PA CNC system was deeply researched and then the development program of the control module was designed in this paper. By means of researching on the operation mechanism of PA and its software and hardware structure, functional requirements of the control system were analyzed. And then the two sets of control module development scheme were proposed, and the PA hardware circuit design was completed with the installation and commissioning to ensure the security of electrical system.A control module based on PA system suitable for XYZ-3RPS six-axis horizontal type serial-parallel mechanism tool was developed, including three parts as CNC control algorithm, HMI human machine interface and PLC module. Firstly, the dynamic link library file was compiled which enabled the control algorithm to be embedded into CNC using the software VC++ 6.0 as the development platform, through which the mode switching between actual and virtual axis and data processing and other functions were achieved; Secondly, a more perfect human-machine interface was developed according to the function requirement, with the development of post processing program which could be called by HMI and the development of axis information display program which achieved real-time display of the length information of actual axis; Finally, PLC program was developed to complete the auxiliary monitoring and other functions.At last, propeller processing experiment was done in this paper. The three-dimensional model of the propeller was established, the technological process was analyzed, and the automatic programming was completed by using UG CAM module. After the tool path simulation visualization, the cutter location file was generated and imported to the developed system, through further post-processing the cutter location file was transformed into the driven data which could be identified by PA system, and then the machining experiment was achieved which verified the effectiveness and the stability of control algorithm and the system. In addition, by comparing the advantages and disadvantages of the two sets of development programs, the prior system development scheme for different functional requirements of the machine was proposed. |
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