Performance Evaluation of Real-Time ROS2 Robotic Control in a Time-Synchronized Distributed Network

Modern robots are mainly controlled by monolithic black-box controllers provided by the individual manufacturers. In research institutions the first version of the Robot Operating System (ROS1) is widely used for different applications. However, ROS1 lacks real-time capable communication. The ongoing development of ROS2 promises to break this paradigm. By employing Data Distribution Service (DDS) as a middleware the modular architecture aims at providing realtime capabilities. This study assesses the current prospects and limitations of ROS2. It gains novel insights towards improved and, in particular, reliable results regarding latencies and jitter. To this end, the allocation and transmission of ROS2 messages is evaluated in an example application for robotic control. An oscilloscope is applied for external validation of the measurements in such a time-synchronized distributed network. The complete application is set up from non-real-time object detection towards real-time control via ROS2 and EtherCAT. An in-depth evaluation of the ROS2 communication stack on a single host and in distributed setups is included. With real-time safe memory allocation and highly privileged ROS2 processes real-time capabilities are ensured.