Research And Application Of Vehicle Communication Protocol Based On CAN Bus

CAN(Controller Area Network),which is a kind of industrial field bus,is usually called CAN bus,which is CAN bus.It is widely used and is one of the most widely used open field buses in the world.CAN was first developed and proposed by Bosch in Germany in the 1980 s and later used in the automotive industry.The communication between modern automotive electronic control devices has become more and more complicated due to the increasing number of electronic devices in the car.In order to reduce the ever-increasing in-vehicle signal lines,a serial CAN bus has been developed.The most outstanding performance of CAN bus data communication is its reliability,real-time and flexibility,and its network utilization is better than other fieldbus.Therefore,it is the most widely used in the automotive field.Many famous automobile manufacturers in the world,such as Mercedes-Benz,Hyundai,Jaguar,Volkswagen,etc.,have begun to use CAN bus to realize internal communication between the vehicle and various electronic devices.With the continuous development of the automotive industry,the requirements for real-time network control of automotive control systems are becoming increasingly accurate.The scheduling method using only the non-destructive arbitration of the CAN bus has been difficult to meet the real-time requirements in the real world.Combining the excellent network scheduling algorithm into the CAN bus can effectively enhance the timely and accurate transmission of messages in the CAN network,ensuring that the message can reach the target node accurately within the specified deadline,which can effectively avoid the occurrence of security risks.We can study the related scheduling algorithm of CAN network and analyze its real-time performance,which can not only help theoretically reduce the delay of CAN network information,but also has practical value.This paper first introduces the CAN bus,including its development research status and technical specifications.Then the time characteristics of the message in the CAN network are analyzed.The quantization formula of the message delay in the worst case is studied,and some excellent scheduling algorithms are studied.The more general static scheduling DM algorithm and dynamic scheduling are studied.EDF algorithm.Combining the advantages of the two algorithms,the message is divided into strong real-time information,weak real-time information and non-real-time information according to the time characteristics.A hierarchical structure is proposed,and a hybrid scheduling algorithm combining EDF algorithm and DM algorithm combined with message value density is proposed..Hard real-time messages are scheduled using the improved EDF algorithm and assigned to higher priorities;soft real-time and non-real-time messages are scheduled by the DM algorithm and assigned low priority.Based on the above series of studies,the CAN network simulation model is used to establish the CAN network model,and the three scheduling algorithms are simulated respectively.The simulation results show that the proposed hybrid scheduling algorithm can effectively improve the real-time performance of the system and reduce the delay of message transmission.