Design Of Multi-axis Servo Drive System Based On EtherCAT Bus

The "Made in China 2025" action plan clarifies that China will enter the ranks of manufactur-ing powers in the future,and the development of manufacturing industry will undergo rapid reform and innovation.In today's hot robot industry,as the core component of the robot,the servo system will develop in the future with high precision and multi-axis.At present,pulse-type drivers are used in industrial servo systems.Such servo drives cannot meet the requirements of large-scale data transmission and data synchronization of multi-axis robots.Therefore,this paper proposes a solu-tion with high integration and easy implementation of EtherCAT bus multi-axis servo drive system.Firstly,the advantages of the bus type multi-axis servo drive are analyzed,and the difference between the EtherCAT bus and the conventional bus is compared.Then an integrated six-axis servo drive system was designed with FPGA and LAN9252 as the core.In the hardware design,the common bus voltage is used to improve the power efficiency;the sampling chip AD7266 is used to ensure the simultaneous acquisition of the two-phase current of the motor;the IPM module with undervoltage and overcurrent protection is used to improve the system reliability.In the control logic design,the timer sequencing is used to stagger the time of current sampling and current loop update,which reduces the influence of current sampling delay on the current loop control perfor-mance.The improved T method is used to measure the speed and solve the traditional IM/T method.Slow speed response and low accuracy.In addition,the EtherCAT communication and application layer functions are implemented in Nios ? which the soft core processor of FPGA.This implemen-tation improves system integration.Finally,the power supply,input and output signals and EtherCAT communication perfor-mance of the system hardware are tested.The results show that the EtherCAT minimum distribution clock DC period is lms,the transmission delay is 1.7us,and the synchronization error is within 30ns.On the TwinCAT,the servo drive system is controlled online and the servo motor status sig-nal is observed;the servo drive speed loop response time is 16ms,and the position loop tracking time is within 100ms without the position being out of tolerance.Experiments show that the use of EtherCAT bus communication can guarantee real-time and synchronous control of multi-axis servo motors.