A Research of Distributed Servo System Based on EtherCAT Bus

Aiming at the multi-motor collaborative servo control demand of electromechanical system, the distributed multi-motor servo control principles based on fieldbus are researched, adopting EtherCAT real-time Ethernet as the data communication fundamental network. Based on EtherCAT slave servo node of DSP, EtherCAT slave controller and embedded Master node, the multi-motor servo control system combined field and remote measurement, and control is built jointly. Aiming at the periodic and aperiodic control tasks in the system, the servo control and acquisition tasks are scheduled through real-time operating system in the embedded Master node to meet the real-time demand of the system. Meanwhile, in order to solve the synchronization problem between nodes of the distributed system, the timing unit is designed based on DC distribution clock and EtherCAT clock synchronization algorithm to realize slave synchronization function in network. The test result shows that, the distributed multi-motor servo control system is running stably and reliably with high timeliness, and the synchronization precision between nodes of the servo slave is less than 1 us, with high application value.