Research And Implementation On The Real-Time Assurance Mechanisms Of Robotic Distributed Computing Framework

Currently,the robot has been widely applied in the industrial field,and gradually develops in the fields of house-hold,service industry,military and so on.However,when robot has a deeper expansion in these areas,it faces enormous challenges.Especially in the environment of the complex robot with multi computing nodes and multi-robot system,many new problems has occurred in the mixture of the traditional distributed computing technology and the robot technology.The real-time assurance is the one among them.Robots which act as a direct participant in the physical world,its activity must compromise on the time-related constraints in the physical world,otherwise it will lead to the failure of its tasks,and even causes a disaster.This constraint is equally important to the robotic distributed systems.And the implementation of the real-time robotic distributed application needs the support of the underlying distributed computing framework.The existing mainstream robotic distributed computing framework(such as OROCOS,ROS,etc.)are lack of complete real-time support in distributed environment.This paper focuses on the real-time assurance of the robotic distributed computing application,and proposes the real-time guarantee model,and finally realizes the real-time assurance of the message and end-to-end level.We mainly conduct out research on the following four aspects:Firstly,on the base of the deep research in the robotic distributed computing framework and the real-time middleware,and we concise the common needs in the real-time aspect of robotic distributed application,and propose the implementation model of real-time robotic distributed computing framework in multiple levels,which contains message level and end-to-end level.Secondly,we design and implement the support mechanism of the message real-time assurance in robotic distributed environment based on ROS.This framework integrates DDS into ROS kernel,and makes DDS as the transmission protocol of the transport layer of ROS,so it can provide the method of time constraint to ROS.And then the real-time assurance of robotic distributed computing framework can be achieved.Thirdly,we design and implement the support mechanism of the end-to-end real-time assurance in distributed environment based on ROS.This mechanism determines the priority of the Callback with the priority of the message which the Callback dealing with.And then we adopt the scheduling policy based on priority to guarantee that the Callback which has a higher priority will be dealt with earlier.And finally,this paper has a functional verification and performance test based on the ROS which can provide the support of real time.This article is a useful exploration of the real-time assurance of robotic distributed computing framework.And our research has a very good theoretical value for the implementation of the real-time assurance on the message transmission and multiple nodes completing a task.