Design And Implementation Of Communication Middleware For Robot Based On Publish/Subscribe Technology

Nowadays the hardware that is used to build robot becomes more and more complicated.A variety of high precious sensor and high performance process unit makes modern intelligent robot system become more and more complicated,especially in the communication for robot software.In order to improve the efficiency of software communication for robot,facilitate the developer in building software for robot,this paper researchs the communication mechanism and communication model for robot according the feature of hardware and software realization of robot.According the feature of hardware and software realization of robot,robot software tends to manage all robot hardware unit by multi task.The way of robot software development is similar to distributed computation.Therefore,the publish/subscribe communication model is suited in development of robot software.Linux operating system has been used in lots of field including robot,carrying on research in Linux is reasonable.Robot software has a high demand for real-time.Xenomai(Linux real-time solution)is able to meet the real-time demand of robot software and can be used to improve the efficiency of robot communication.A communication middleware for robot based on publish/subscribe technology,Linux and xenomai by giving priority to communication efficiency is designed and implemented in this paper.The communication middleware supplies same function and api to the xenomai task and Linux task.This paper researches the applicability about the usage of publish/subscribe technology in software communication for robot before adopting it.The implementation principles of xenomai has been analyzed by source code.This paper designs different communication mechanism for different scale(cross-thread,inner-process,multi-machine).Ring buffer is used to manager the user buffer and shared memory which is used in innerprocess communication.The ring buffer of user is designed as lock free while the ring buffer of shared memory is designed as cas lock free.To improve the efficiency of communication,Real-time task of xenomai is used to construct the communication middleware.The heartbeat and log mechanism is used to monitor the running statue of communication middleware.At the end of this paper,a reasonable experiment has been designed which is used to test the performance of communication middleware designed in this paper.By comparing the performance with domestic and foreign representative robot middleware and communication middleware(ROS,LCM,ACH,OROCOS),it proves that the performance of communication middleware designed in this paper is better than others with reliable communication while is not patch on the performance of LCM which uses UDP multicast(unreliable communication).