Research On Multi-Robot Cooperative Communication Technology

With people's continuous pursuit of quality of life and work efficiency,new requirements have been put forward for the working environment and tasks of robots.It is difficult for a single robot to complete a lot of complex work,and multiple robots are required to cooperate with each other to complete the work.With the fusion development of wireless communication,Internet of things,cloud computing and robotics,this research adopts WLAN network and cloud technology to realize the collaborative communication between multiple robots.This paper mainly studies the protocol content,access mode and conflict avoidance algorithm of the MAC layer of the multi-robot communication network,and also studies how multiple robots are connected to the cloud platform in combination with cloud technology to realize mutual communication between multiple robots and remote monitoring of the system.The main research contents of this paper are as follows:1.Analyze and study the topology network structure and operation mechanism of multiple robots' cooperative communication.Through comparative analysis,a hybrid network topology combining ring and star is adopted in the multi-robot cooperative communication network.The MAC layer of multi-robot cooperative communication network adopts 802.11 series protocol.This paper mainly analyzes four operating mechanisms of this series protocol: four-time handshake,carrier interception,frame interval and random retreat.2.Research the access mechanism and conflict prevention mechanism of multi-robot cooperative communication.By using the distributed coordination function DCF access mechanism of four handshakes to access the channel,and using the carrier interception and conflict avoidance of two carrier interception mechanisms of CSMA/CA,the time NAV of the channel was obtained,which solved the data conflict problem of multiple robots to a certain extent.According to the occupancy time NAV of the listening channel,the robot generates a random back-off time-sharing data by using the back-off algorithm when transmitting data,which can greatly reduce the probability of data collision.3.The research improves the traditional binary exponential back-off algorithm BEB,adjusts the back-off window parameters according to the inadequacies of the algorithm,and proposes an improved exponentially increasing exponential decreasing back-off algorithm EIED,and gives the execution flow of the algorithm.The EIED algorithm with different parameters is compared with the BEB algorithm.4.In order to verify the proposed multi-robot network topology and improved EIED anti-collision algorithm,a multi-robot cooperative communication network with mobile robot as experimental object is constructed.A brief introduction to its hardware structure,the structural design of the software platform.This paper analyzes how to encapsulate the related sensor data of the experimental object through CAN protocol,and connects multiple robots to the OneNET cloud platform through TCP protocol.According to the platform EDP protocol,upload,store,forward and encrypt the data of multiple robots in the data link layer.The overall framework and resource model of the platform are studied,and how multiple robots access the platform through WLAN network is briefly analyzed.5.Finally,the MAC layer of the multi-robot cooperative communication network is modeled and simulated by OPNET,and the network performance when using different back-off algorithms is analyzed.It shows the establishment process of robot crowd after multiple robots are connected to the cloud platform through WLAN network,the monitoring interface of a single robot,the equipment overview of the robot crowd and application layer robot response log.The communication performance between multiple robots is debugged through the serial port,and the functional requirements of multi-robot cooperative communication are realized.