Research On CAN FD Bus System Based On FIFO And Priorit

As one of the most important means of transportation for human travel in modern society,the demand for automobiles is increasing,and the application requirements are also increasing.With the development of information technology and automotive electronics technology,the real-time and security requirements for automotive network communication are becoming increasingly stringent,and the limitations of traditional CAN(Controller Area Network)buses are becoming increasingly apparent.The CAN FD(CAN with Flexible Data rate)bus has emerged with its higher bandwidth and larger load capacity.The paper focuses on the research of CAN FD bus system based on FIFO and priority,and the main content is divided into the following four parts:(1)On the basis of in-depth research on CAN FD bus technology,this article constructs a CAN FD bus system based on FIFO and priority.Conduct a systematic analysis of the constructed CAN FD bus network,derive the maximum response time of messages,conduct sufficient schedulability analysis of messages in the CAN FD network with FIFO sequence nodes and priority sequence nodes,and design schedulability analysis algorithms to determine the schedulability of the CAN FD bus system.(2)The CAN FD bus arbitrates based on message priority,which can cause unreasonable allocation of network bandwidth resources and generate certain network latency,making it impossible to ensure the real-time performance of lower priority messages.To solve this problem,a hybrid scheduling algorithm based on CAN FD bus system is proposed.This algorithm combines static and dynamic scheduling algorithms.The static scheduling algorithm uses FIFO adjacent priority sorting algorithm,and the dynamic scheduling algorithm uses improved exponential function partition EDF algorithm.This algorithm effectively solves the problem of priority inversion in average partition EDF algorithm.Experiments have shown that hybrid scheduling algorithms can more effectively assign priority to various messages in CAN FD bus systems,allocate network resources reasonably,and improve system real-time performance.(3)In order to explore the advantages of CAN FD bus,this article conducts performance comparison experiments on CAN bus systems of the same architecture and CAN FD bus systems.The experiments show that compared to CAN bus systems,CAN FD bus systems have lower bus load rates,stronger network reloading capabilities,and still have more data bits reserved,which can be used for later functional expansion.(4)To investigate the impact of FIFO sequences on system performance,the minimum bus rate and maximum bus utilization were compared for different configurations of FIFO sequences and priority sequences in the system.The experimental results showed that using FIFO sequences significantly improved the minimum bus rate required to ensure that all deadlines were met,and reduced the maximum bus utilization achievable to meet all deadlines,which had a significant impact on network performance.Based on this,in the design and development of future automotive networks,priority sequences should be selected as much as possible.On the basis of the above,the number of nodes in the FIFO sequence was studiedExperiments have shown that increasing the number of nodes in the FIFO sequence and grouping messages with similar transmission deadlines can effectively improve network performance when the use of FIFO sequences cannot be avoided.