| At present,most electrolytic machine tools in China are limited in application due to the single function,low integration and inconvenient processing operation,which cannot meet the requirement of complex parts machining.In view of the current shortcomings,a set of high-performance integrated control system for five-axis electrolytic machine tool was developed and its performance was analyzed in this paper.Firstly,the design requirement of five-axis CNC electrolytic machine tool was analyzed.The overall layout,electrolyte system composition and the integration scheme of machining power of the electrolytic machine tool were demonstrated to draw up the overall scheme.The machine tool is of horizontal structure layout with detailed design for the drive system,work table,column of each axis and other parts.The overall machine tool 3D model was established by the UG software.Secondly,the integration scheme of the control system is drawn up to design the hardware of the control system.Based on the comparison of various control schemes,the development scheme of control system integration is proposed based on Siemens 840 Dsl.The hardware structure of the control system was designed.NCU,PCU,servo unit,motor and other components were selected and the system was integrated by calculation and comparison.Distributed control is adopted in the electrolyte system.Parameter setting and real-time sampling of working parameters,such as processing temperature,voltage and hydraulic pressure,were realized by establishing the main & sub PLC communication through PROFUBUS bus.Heating and parameter measurement circuits were also designed.The input& output nodes of PLC's switch value and analog value were allocated and the corresponding control circuit was designed.Thirdly,the mathematical model of closed-loop servo control of the machine tool was established by automatic control theory.Permanent magnet synchronous servo motor and ball screw structure were established for X-axis,Y-axis and Z-axis of the motion system,and the mathematical models of current loop,velocity loop and position loop control were establishedto realize the full closed-loop control of the system.The parameters of X-axis,Y-axis and Z-axis closed-loop control model were set and the servo control performance of X-axis,Y-axis and z-axis was analyzed by Matlab/Simulink software.Taking the tool path of aero-engine blade as an example,the linkage performance of the three axes was analyzed,and the deviation between theoretical path and simulation path was analyzed by UG software.Finally,the PLC control program design and control software development were carried out based on the control system hardware,and the system was debugged.The hardware of the machine tool S7-300 PLC control system was configured by step 7 software of Siemens,and the system's PLC control program was designed to realize the module control of numerical control system,processing power supply and electrolyte system of the machine tool.In the development of control software,the human-machine interface of the control system was designed and transplanted into the environment of VC++ by QT software.Then,the control program was developed by Siemens Operator Programming Package development toolkit and Visual Studio platform.The NC program call,data acquisition,fault diagnosis and automatic control of machining process of the machine tool were realized by the Siemens programming package functions and the call and programming of VC++ runtime.In the process of development,the software,hardware and the functions of each module of the control system were debugged.The result showed that the communication between the host computer(PCU)and the sub-module controller(NCU,PLC,single-chip microcomputer)was normal and the system hardware ran reliably.The control software and HMI compatibility was good with high system integration and each function test was normal. |
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