Research On Multi Axis Synchronous Model Predictive Control Of EDM

With the continuous improvement of servo technology in recent years,the application of multi axis synchronous system is more and more widely.Fully considering the factors such as stiffness,damping and quality that affect the dynamic performance of mechanical system,the establishment of a high-precision multi axis synchronous system of EDM gantry machine tool is of great significance to the development and production of CNC equipment such as EDM machine tool.In the face of the current multi axis synchronous control has poor synchronization performance,easy to lose its stability due to external disturbance and other defects,this paper aims at the gantry EDM machine tool,according to the characteristics of its electric machining shaking,translation and z-axis repeated reciprocating machining,the X,Y,Z-axis of the machine tool are using dual axis synchronous control,through the establishment of dual axis feed system model and complete the simulation analysis of different schemes The software and hardware design of the machine tool multi axis synchronization control system is completed,and the synchronization performance of the machine tool is verified by experiments.Firstly,according to the structural characteristics of the machine tool,taking X-axis as an example,the dual axis feed system and servo system of the machine tool are modeled.By elaborating the parallel control strategy and cross coupling control strategy in detail,and making simulation analysis,it is determined that the synchronization performance of the cross coupling control strategy is better.On this basis,the model predictive control algorithm based on cross coupling control is proposed,and the simulation analysis is completed.Compared with the traditional PID algorithm,the results show that the model predictive control algorithm has higher synchronization control effect and better anti-interference performance.According to the simulation results,the three-axis overall two axis synchronization system model of the machine tool is built,and the online simulation is carried out by using the above controller to verify that the synchronization performance of the system is greatly improved.Secondly,FPGA is selected as the main control chip of the circuit control board to complete the FPGA Software and hardware development and design,and the program design of each module of the dual axis synchronous controller is completed by using Verilog language.The logic function simulation is completed in Modelsim,and the program and hardware debugging are completed on the experimental debugging platform.By analyzing and comparing the control mode and driving mode,the most suitable scheme is selected,and the overall scheme design of the experimental platform is finally determined.Finally,the single axis semi closed-loop and double axis full closed-loop experiments are completed on the built two axis feeding experimental platform to verify the feasibility of the experimental platform and the experimental scheme to achieve high-precision positioning of two axes.On this basis,the two axis synchronous control experiments with different control strategies and control algorithms are carried out.By analyzing and comparing the experimental results,it is determined that the two axis synchronous control scheme based on cross coupling control strategy and model predictive control algorithm has higher control accuracy and better synchronization effect.