Research On Highly Reliable Message Packing For The Static Segment Of Automotive FlexRay Network

With the increasing demand on the safety and comfort, the modern vehicle is developing towards the direction of electronization, networking and intelligentization. More and more electronic control units(ECUs) are applied to the automobile, and the demand on high-speed real-time communication among ECUs are also growing. In the trend, the automotive bus is accepted by most automotive manufacturers. Compared with the traditional CAN bus, the FlexRay bus has great advantages of high bandwidth, high fault tolerance and meets the modern automobile’s demand better, which is recognized as the next generation standard of automotive bus.The dissertation is supported by national nature science fund of China and some enterprise research projects. The highly reliable message packing for the static segment of automotive FlexRay network is studied. At first, considering the deficiency of the existing message packing mechanism, The concept of bus utilization rate is proposed, and the upper and lower bounds of the frame payload is derived. On the basis, with the target of realizing highest bus utilization rate and the constraint condition of satisfing message scheduling, the message packing model is estabilished. Refer to the classic packing algorithm, the descending first fit algorithm of message packing is designed. Secondly, considering the message sending failure, the message retransmission mechanism is introduced. The global success rate and message retransmission times are given. A calculation model of the optimal message retransmission times for the specified reliability is established, and the SNMRTLB algorithm based on the greedy strategy is designed. Finally, developing the FlexRay network design platform and carrying on the simulation experiments to confirm to the method of thesis. The experimental result shows that the proposed method not only can effectively improve the bandwidth utilization of FlexRay network, but also can ensure the reliability of network transmission. The research has a positive theoretical significance and engineering value for improving the real-time and reliability of the vehicle network communication.