Research And Realization For The Multi-Axis Servo Control System Based On EtherCAT Bus

With the continuous improvement of industrial automation's level,multi-axis servo systems are increasingly used in various fields.At the same time,the synchronization performance requirements for multi-axis servo systems are also increasing.Traditional fieldbuses have struggled to meet existing requirements.German automation control company Beckhoff proposed the EtherCAT bus technology based on standard Ethernet in 2003.The technology has the advantages of simple system configuration,flexible topology,efficient transmission rate,high real-time performance and low cost.At the same time,its distributed clock mechanism can synchronize all slave clocks supporting this mechanism,making clock jitter between slave nodes.Far less than lus.This paper proposes and designs a two-axis servo control system based on ST's STM32F407 and slave controller based on Microchip's LAN9252 chip,which verifies the synchronization performance of EtherCAT in servo control.This paper first studies the development of industrial network technology from fieldbus to industrial Ethernet,and introduces and compares several common industrial Ethernet technologies.In-depth study of EtherCAT technology,detailed analysis of its operating principle,data frame structure,communication mode,distributed clock mechanism,state machine and application layer protocol.Then,this paper designs and builds a hardware platform based on STM32F407 chip and LAN9252 chip,analyzes and expounds the main circuit interface design.The three closed-loop vector control of the permanent magnet synchronous motor is realized based on the STM32CubeMx and STM32 MC SDK software environments.Finally,using the PC-side TwinCAT configuration software as the master station,a servo control platform based on EtherCAT is built.The synchronization algorithm of the servo system is realized by synchronizing the execution time of the position loop,the speed loop and the current PWM loop by using the precise synchronization signal generated by the EtherCAT slave station in the DC mode.