Cyber–Physical Codesign of Field-Level Reconfigurations in Networked Motion Controllers

To be successful in the quickly evolving future of machine building and meet the increasingly complex requirements of manufacturers, equipment manufacturers face challenges of reconfigurability on the motion controller. This article proposes a cyber-physical codesign approach to enable plug-and-play of field devices via real-time Ethernet in controllers. In our proposal, we first design a modular runtime framework to facilitate auto-discovery and self-configuration of servo drives with EtherCAT. Then, we implement a self-adaptive period synthesis method for real-time scheduling. The method can automatically attain a combination of minimized periods for communication and control task during startup and achieve dynamic compensations of drifts and jitters occurred in the network. Through experiments, we show that for various combinations of cyber-physical settings, our proposal can ensure low jitters ($<; $10 μs) and stable latencies with a 125 μs cycle time and achieve runtime reconfiguration with a 250 μs or larger cycle time.