Quality Of Service Design And Implementation Of DDS Communication Middleware

Data Distribution Services(DDS)are recognized and used in many areas.DDS is a data exchange standard and a distributed system for real-time data exchange.It is a message exchange architecture oriented to publication/subscription.At present,the most mature and widely used scenario is the on-board system.Compared with other middleware,DDS is characterized by a data-centric publishing and subscription mechanism and diversified Quality of Service(Qo S)policies.Developers can control the data communication of DDS communication middleware by manually configuring different Qo S policy parameters.The traditional communication model is based on the client server model,which has some problems such as strong coupling and different functions need to be developed in different complex communication scenarios,which increases the burden of transplantation technology on the system.Aiming at the problems such as strong coupling and poor flexibility of traditional communication model,this thesis carries out a research on DDS communication middleware,focuses on the function method of quality of service strategy of communication middleware of data distribution service,carries out Qo S overall design and Qo S sub-module function design of data distribution service,and builds a test environment to verify the function and performance of communication middleware.The main research contents are as follows:1.Aiming at the problems of communication nodes in traditional communication middleware,such as difficult to flexibly control data delivery and poor data availability,according to Qo S function description of DDS specification,function division of different quality of service strategies is carried out,and Qo S overall design of DDS communication middleware is carried out to provide Qo S control interface for upper-layer applications.A kind of Qo S configurable communication middleware is implemented.2.To solve the problem that different communication functions are needed in complex communication scenarios,this thesis designs different Qo S module functions based on DDS specification,including system resource control,entity status monitoring,data transmission backup and other functions,providing a good communication control method for distributed real-time data transmission.3.Aiming at the problem of unreliable transmission in traditional communication middleware and referring to traditional reliable transmission methods,this thesis designs a RUDP reliable transmission protocol based on UDP protocol based on network group management protocol,designs the protocol header,retransmission mechanism and other functions,improves the reliable data transmission method and reduces the total transmission delay in the process of data transmission.Finally,a radar transmission test environment is built based on the measured data of millimeter wave radar,and the function and performance of the designed communication middleware are tested.The results show that the communication middleware designed in this thesis can meet the loosely-coupled communication function,and can configure different quality of service policies to control the communication process,which verifies the reliability and real-time performance of radar data transmission.Compared with Open DDS,the DDS quality of service strategy function designed in this thesis reduces the average memory usage by 27%.The designed reliable module function reduces the total transfer time by 5.7% when the packet loss rate is high.