Research Of Automotive CAN Network Real-time Scheduling Method

With the development of automobile industry technology, the electronic controlunits on vehicle’s body is growing and networking becomes automotive electronicsdevelopment inevitable trend. CAN (Controller Area Network) is a serialcommunication bus system supporting distributed control. With the advantages ofhigh communication speed, low cost and strong anti-interference ability CAN iswidely used in the field of vehicle control. The application of CAN reduces thecomplexity of the automotive network system, and increases the vehicle’s safetyand comfort. This subject is supported by national electronic information industrydevelops fund, searched and collected a large number of domestic and foreignresearch data and information, analyzed the communication mechanisms of CANand current major CAN network scheduling methods in detail, and studied how toimprove the existing network scheduling methods to achieve the purpose ofincreasing network performance. This research has important practical significanceon the application of CAN bus technology.This thesis described the background of automotive CAN network and analyzeddomestic and international research present situations. To meet the real-time andfairness requirement of CAN network, a mixed scheduling method based ondynamic priority allocation (DPA-MS) was presented. Elementary time slice wasintroduced into DPA-MS to implement bottom-layer round-robin scheduling basedon non-fixed cycle by transferring trigger message and stop message. DPA-MSintroduces Total Bandwidth Server (TBS) to implement upper-layer dynamicpriority mixed scheduling of periodic and non-periodic messages by EarliestDeadline First (EDF) algorithm. According to the system requirement, CANnetwork nodes and scheduling model were designed, and Simulation was carriedout on CANoe experimental platform. The experimental results verified thefeasibility and effectiveness of DPA-MS.The significance of this research is to improve the real-time of CAN networkcommunication and reduce the maximum delay of the messages with low priority inthe process of transmission, and to effectively improve the transmission fairnessbetween periodic and non-periodic messages and has a good performance ofscheduling both types of messages while using network bandwidth effectively...