| With the development of industrial manufacturing industry,its degree of networking,decentralization and intellectualization has been continuously improved,and the motion control system based on Industrial Ethernet has been more and more widely used.Among them,the networked motion control system based on EtherCAT has high transmission speed,good real-time and synchronization performance,flexible topology,simple configuration and operation,and low cost.It has gradually become a hot research topic and trend in the field of motion control.In this paper,EtherCAT master.is studied for motion control.Firstly,aiming at the application of EtherCAT master in motion control,the overall framework of EtherCAT master is designed on the basis of in-depth study of the principle of EtherCAT technology,and the software scheme and functional modules of the master are expounded.The embedded hardware is selected,the real-time scheme of Linux + Xenomai system is adopted,the IGH EtherCAT Master open source protocol stack is analyzed,and the overall scheme design of the EtherCAT master is completed.Then,aiming at data communication between master and slave,the data processing mechanism of EtherCAT process is studied,the CoE communication model of master and slave of motion control system is established,and the EtherCAT bus configuration program is designed.Aiming at bus network synchronization,the algorithm realization of clock synchronization,distributed clock operation,clock synchronization program and configuration program of synchronization signal are studied.Then,the interpolation algorithm of the master is developed,the cubic S-type acceleration and deceleration control model is studied,and the straight line interpolation algorithm and arc interpolation algorithm are designed.The trapezoidal interpolation sequence is constructed and the interpolation error is allocated to improve the interpolation accuracy and avoid the sudden change of speed.The speed look-ahead of continuous line segment interpolation is carried out to reduce the impact of frequent start and stop of machine tools in continuous machining process,and the speed look-ahead Program is designed.The correctness of interpolation algorithm and the effect of speed foresight are verified by simulation analysis.The overall framework of servo control system based on EtherCAT is designed.The bus topology and the selection of slave module(servo controller)are introduced.The periodic synchronous communication mode between master and slave is designed.The servo control application program is developed.The periodic synchronous position(csp)control mode of EtherCAT master to multi-axis servo is realized.Finally,a test platform is built to test the performance of EtherCAT master,including task scheduling delay test,periodic real-time task test of master and synchronization performance test of distributed clock network.The results show that the real-time and multi-axis control synchronization of the main can meet the requirements of motion control.Aiming at the multiaxis motion control performance of the main,servo position control and three-axis engraving and milling machine tool processing experiments are carried out.The results show that the EtherCAT master can achieve accurate motor position control and meet the requirements of multi-axis motion control. |
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