Real-time Ethernet POWERLINK Communication for ROS. Part I. General Concept

This research is focused on the integration of Ethernet POWERLINK (EPL) fieldbus with the Robotic Operating System (ROS) for real-time control tasks. In this part, we analyze latencies and jitter introduced by the Linux operating system, ROS and the openPOWERLINK stack. To increase the determinism of the operating system, we propose using the PREEMPT_RT patch from OSADL. To ensure the simplicity of process data exchange, we offer software that implements the openPOWERLINK stack with a standard ROS interface for applications running with a cycle time of more than 10 ms, and a specialized API based on the POSIX infrastructure for high-speed applications with a cycle of 10 ms or less. The introduced concept covers both Managing (MN) and Controlled (CN) nodes, making it possible to easily integrate Ethernet POWERLINK communication in any robotic application task. More details about hardware and software implementation issues will be described in the paper dedicated to the second part of this research.