CompROS: A composable ROS2 based architecture for real-time embedded robotic development

Abstract

Robot Operating System (ROS) is a de-facto standard robot middleware in many academic and industrial use cases. However, utilizing ROS/ROS2 in safety-critical embedded applications with real-time requirement is challenging because of C1) Non-real-time underlying hardware, C2) No control on the host OS scheduler, C3) Unpredictable dynamic memory allocation, C4) High resource requirement, and C5) Unpredictable execution model for ROS nodes. In this paper, we address these limiting factors by proposing a hardwaresoftware architecture -CompROS-for ROS2 based robotic development in a Multi-Processor System on Chip (MPSoC) platform that. The proposed hardware architecture consists of a Hard Real-Time (HRT) RISC-V based subsystem implemented in the Programmable Logic (PL) part of the MPSoC platform, a Soft Real-Time (SRT) ARM-based subsystem in the Processing System (PS) part of the MPSoC platform, and a Non-Real-Time (NRT) PC. While the proposed hardware architecture along with a partitioning layer overcomes the first two limiting factors, the rest are managed by the proposed multi-layer software architecture. We make a bare-metal implementation of XRCE-DDS standard for PL-PS communication, while peerto-peer PL-PL communication is done through a proposed realtime publish-subscribe approach. The reliable communication for PS-PLL communication is done through utilizing C-HEAP protocol. Further, we integrate ROS2 software layers on top of the proposed hardware and software layers. Finally, with respect to C5, we present a real-time execution model of ROS2 nodes by a mapping of ROS2 entities to CompROS entities, which is validated through experimental results. We run ROS2 middleware with an executable size of less than 200 KB on an MPSoC platform.

Transactional TF: Transform Library with Concurrency and Correctness

“…The Robot Operating System (ROS) [1] is widely utilized in the robotics field, and its internal mechanism has been actively improved to enable low overhead inter-process communication [2], a real-time property [3], and a NoC communication scheme for the many-core architecture [4]. The Transform Library (TF) [5] plays a key role in ROS as it manages the transformations between each coordinate system in directed forest data structure and has methods for registering the transformation information and computing the transformations.…”

“…LOTROS [2] proposed a low overhead IPC to replace the nodelet package. CompROS [3] proposed real-time features for ROS 2. ROS-lite [4] proposed an NoC communication scheme for many-core embedded platforms.…”