Development Of Pulse Controller For Robot Servo System Based On EtherCAT Bus

With the progress of science,robots are not only used in the traditional manufacturing industry,but also in medical treatment,catering and other industries.However,with the application of robots in more and more fields,the requirements for robot servo controllers are becoming higher and higher.Firstly,the robot servo controller is required to have strong real-time performance,because robots are generally engaged in tasks with high precision and repeatability.Secondly,the robot servo controller needs to be distributed,because with the increase of the complexity of the task,it is difficult to be completed by only one robot,so multiple robots are needed to complete the task.Finally,the robot servo controller is required to have good openness,which can support multi-instruction input and output,as well as the increase of the number of robot axes.In this paper,a robot servo system pulse controller based on EtherCAT bus is designed to meet the current requirements of robot servo controller.The servo controller uses EtherCAT bus as the communication bus,which can increase the number of slave stations in the servo system by virtue of its good compatibility without changing the whole system structure,overcoming the disadvantages of the closed structure of the traditional servo controller.The EtherCAT bus has the characteristics of faster communication rate and low communication delay.It can improve the real-time performance of servo system.In addition,this design uses THE FPGA chip as the core processor of the servo controller.Because the FPGA chip has the advantages of good parallelism,rich I/O resources and good real-time performance,it can fulfill the work requirements of the servo controller well.The main work of this project is the development of communication unit and servo control unit.The EtherCAT IP core is used in the communication unit to complete the construction of EtherCAT slave station,and the application layer is designed according to the actual application situation,so as to complete the task of EtherCAT communication.The main task is to receive the instructions from the master station to the servo control unit and transmit the feedback information to the master station.Servo control unit is mainly written in the FPGA chip pulse driver module,encoder data acquisition module and IO status module,including pulse driver module mainly complete the command parsing and according to the order form the pulse signal to the servo drive,encoder data acquisition module is mainly responsible for collecting the position of the encoder information,realize the feedback control,The IO state module is mainly responsible for collecting the state information of the servo motor and sending the information to the communication unit for transmission to the EtherCAT master station.After verification,the whole servo pulse controller can complete EtherCAT communication function and pulse delivery functions.