EtherCat Network Control Design And Realization Of Servo Drive

With the development of the industry, servo drives become more and more important in industry production and manufacture. Meanwhile, requirements for servo drives in reliability, speed and stability are also increasing in order to adapt to complex environment. Digital, modular, intelligent and network become the major trends of servo control system. Motion control system based on Industrial Ethernet control are increasingly being applied to practical industrial due to its scalability, high reliability, fast data transfer rates and remote control, etc.In this paper, the network technology of servo system based on EtherCAT is studied. To develop standard servo system communication interface, CANOpen protocol is implemented in the application layer of EtherCAT. The EtherCAT and CANOpen principle and protocol standards are analyzed and firstly to prepare for the slave stack design. Then several key issues are studied in the development of the slave stack, which consist of cutting of CANOpen protocol, real-time problem of data transmission and synchronization performance etc. Finally hardware is designed and software stack is implemented based on the EtherCAT theory. Hierarchical method is used in the slave stack software design, the slave stack software design consists of three layer: hardware driver layer, data link layer, application layer. The hardware drive layer is mainly used to drive the EtherCAT slave controller by the MCU. The data link layer mainly consists of acyclic data communication, cyclic data communication and state machine control. In the implementation of the application layer, the traditional application layer protocol CANOpen is cut and complement for use over EtherCAT and SDO and PDO communication are achieved based on the new CANOpen protocol. Then several standard servo drive modes are designed according to the DS402 protocol. Finally the slave stack is integrated with the exited servo drive software to construct networked servo slave. Finally experiments are carried out on the servo slave and the results are analyzed.