Research And Implementation Of Ros2's Support Extension For RTOS

In recent years,the robot industry has developed rapidly.With the rise of artificial intelligence and the Internet of Things industry,a variety of robot products have begun to appear in people's vision.However,the development cycle of robot products is relatively long,which contradicts the market's demand for robots.Robot Operating System(ROS)is an excellent middleware for robot messages.The use of publish and subscribe messaging mechanism realizes the decoupling between the various modules of the robot,and realizes the high reuse of robot software modules,which gradually occupy an important position in the robot industry.Many startups and scientific research institutions are developing on ROS.As the scope of application of ROS continues to expand,some of the shortcomings of ROS have begun to emerge.For example,the requirement for computing resources is high,and the centralized node management method makes the system unstable,which is not suitable for use on small robots that use embedded microcontrollers.In order to make up for the various shortcomings of ROS,ROS officially designed and developed an improved version of ROS2,and released the first official version of ROS2 on December 9,2017.ROS2 still retains the excellent mechanism of communication using the publish and subscribe mechanism,while using DDS(data distribution service)as its underlying communication mechanism,so that ROS2 has completed a true decentralization,making ROS2 a distributed robot operating system,while Communication performance is also improved.After the release of ROS2,it has received extensive attention,and Microsoft has also provided ROS2 extended support for Visual Studio Code.However,ROS2 currently does not support the use of embedded microprocessors or microcontrollers,nor does it provide support for any embedded real-time operating system.Therefore,the current ROS2 still cannot be used in miniaturized robot products.This has led some companies to abandon the use of ROS2,limiting the development of ROS2.Therefore,providing ROS2 support for a small embedded environment can make ROS2 better applied in the robot industry,and has great positive significance for the application of ROS2 and the development of the robot industry.The main work of this article is to find that ROS2's lack of support for the embedded microcontroller environment has hindered the widespread application of ROS2,and for ROS2,a proxy mechanism is proposed to implement ROS2 running on a microcontroller with limited resources.The method that the node can achieve seamless and compatible communication with the ROS2 node on the PC.In order to complete the support of ROS2 for the embedded environment,the currently used STM32 platform with more universality and higher universality is selected as the experimental environment.The embedded real-time operating system selects NuttX,which supports the POSIX standard very well.Through a series of configuration of NuttX,it was transplanted to STM32,and the relevant hardware driver was adapted.Use Micro XRCE-DDS specifically for extreme resource-constrained systems as the ROS2 low-level DDS applied to STM32.In order to enable Micro XRCE-DDS to be used like the DDS implementation supported by ROS2,this article refers to the ROS2 software architecture to write the ROS Middleware Interface(ROS Middle Ware)and ROS Client Library(ROS Client Library)corresponding to Micro XRCE-DDS and organized the corresponding API interface.After writing samples and system tests,it is shown that the ROS2 designed and implemented in this paper supports RTOS extension system to realize the STM32 microcontroller running the embedded real-time operating system NuttX.The client server architecture provided by Micro XRCE-DDS and runs on PC the ROS2 standard node on the machine realizes seamless and compatible communication,and the stability also meets the requirements.Completed the goal of this article.