Closing the motion control loops via industrial ethernet network

Abstract

This paper deals with a problem of feedback compensator design for motion control loops equipped with industrial Ethernet communication protocols. The main goal of the paper is to choose proper control structures for a supervisory control system which have to deal with the time delay caused by the communication channel and compare the results with a standard cascade control scheme which is implemented directly in a frequency converter. The discrete-time state-space model of the system is derived and several advanced algorithms for time delay compensation are proposed and evaluated by simulations. Finally, the validity of the used methods is verified experimentally with a Yaskawa servo-drive equipped with EtherCat communication protocol. It is shown that proper control structure is able to compensate the effects of communication delay and the results are comparable to direct implementation of the motion control loop in the frequency inverter.

Study on real-time industrial control networks

“…However, these works did not consider network delays in the controller design. Reference [93] discussed several algorithms which compensate constant time-delay in order to achieve improved performance of a motion control application and the proposed compensation schemes were verified by observing the disturbance and step response from a Yaskawa servo drive with EtherCAT interface. The probability distribution of the delays caused by PROFINET networks was investigated in [17] These industrial processes can be executed synchronously or asynchronously, depending on the system configuration [105].…”