Research On The Vehicle Body CAN Control Network Based On Hybrid Scheduling Algorithm

Vehicle as one of the most widely used transportations in the modern society,occupies an indispensable position in people’s lives. With the development ofautomotive electronic technology, the vehicle manufacturers are constantlydeveloping new functional vehicle to meet the growing needs of people, the electroniccontrol units of the vehicle have become more and more. The various wire harnessand doubled increased electronic control units make the vehicle body a large andcomplex system, occupy a lot of the effective space, increase the difficulty ofassembly and maintenance, reduce the reliability of the system, raise the vehicle cost.Therefore, constructing electronic, networked, functional vehicle network controllingsystem has become the main direction of developing.In this thesis, through studying on CAN protocol and combining thecharacteristics of electronic control units, constructing the vehicle body CAN networkbased on a universal body model. Network time delay is generated from thecommunication mechanism of CAN protocol which means scheduling according tothe priority of information. This communication mechanism may cause the allocationof network bandwidth resource, and cannot guarantee the real-time property of lowerpriority information. To fulfill the requirements of control in vehicle body network,hybrid scheduling algorithm in which the static scheduling is framework combinedwith the dynamic scheduling is designed, and it guarantees the real-time of messageresponse. The priority promotion hybrid scheduling algorithm based on deadlineindex partition method is proposed, which not only effectively solves the limitation ofthe deadline range encoding digits but also guarantees the feasibility of hybridscheduling algorithm. The schedulability of the vehicle body CAN control network isevaluated through the schedulability analysis methods. Using the hybrid scheduling algorithm can satisfy the requirements of network control system, we guarantee thebroadband utilization rate and ensure the real-time of different types of messages, thusimproving the overall performance of network control system.In order to verify the performance of the vehicle body CAN control networkbased on hybrid scheduling algorithm, the basic characteristics of the message can beobtained through the simulation, testing and analysis of using CANoe simulationsoftware. By comparing the performance of vehicle body control network based ondifferent algorithms, it can verify the superiority of the reasonable allocation ofnetwork bandwidth resources and effective scheduling of all kinds of messages. Thisresearch has profound significances on the theoretical basis and reference value.