This paper proposes a method to improve the position control synchronization performance by synchronizing the controller operation between servo drives based on the synchronization signal of the EtherCAT(Ethernet for Control Automation Technology)distributed clock. In order to synchronize the operation of the controller between the servo drives, the phase of the operating frequency of the PWM(Pulse Width Modulation) module for motor control was synchronized based on the synchronization signal. At this time, the operation sequence of the current, speed, and position controller of the servo drive operating based on the PWM operating frequency was rearranged. Therefore, the servo drives on the network run the same controller at the same time. And the time at which the master's command is reflected to the drive's controller and the time at which the drive's status information is acquired coincided among the drives. After establishing an experimental environment in which servo drives are arranged in the EthercCAT network system, we verified that the position synchronization performance between servo drives applying the proposed method is improved.

The Industrial Ethernet technology enables advanced control architectures and offers several advantages for high precision multiple motors actuation. This paper presents the implementation and analysis of a motor drive with EtherCAT, an industrial standard for real time Ethernet. Considering the characteristics of the implemented software and the network interface, the motion and time-response of motor actuation for the networked Mobile Inverted Pendulum have been analyzed. Using the analysis with the task execution times measured from the developed drive, the performance characteristics of the drive in respect of the maximum achievable throughput have been verified by comparing to the conventional RS232.