A Typical Application of FlexRay Bus in the Vehicle

Abstract

Objective. FlexRay is a new and high-powered bus which is designed to achieve the purpose of “X-by-Wire”, may be one day, the CAN bus will be replaced by FlexRay bus. Although this is a high speed and reliable bus, but it is very difficult to apply this bus in the vehicle. The cost is too high, by now on, only a few top grade cars like Audi A8 and BMW X7 use the FlexRay bus. We are doing the research about how to apply the FlexRay in a low cost and feasible way. Methodology. FlexRay is a high cost bus: 1. The FlexRay controller and the MCU which support FlexRay communication is very costly. 2. The software design is very difficult, and there are no uniform guidelines to develop the system. Our research focus on the vehicle network’s strategy, the uniform FlexRay develop standards as well as the tool chain, the uniform diagnostic strategy and software reprogram strategy. We can use the FlexRay bus as a subnet of the vehicle. The important module like ECM, TCM, ABS module use FlexRay, other module like BCM, SDM, IPC use CAN, there will be a central gateway to transmit the signals between the FlexRay bus and CAN bus. If more and more module suppliers can follow our standards, the cost will be low and the system development will be easy. Results. Based on the ISO and FlexRay Union’s documents, we have developed some standards for the FlexRay, these standards contains the FlexRay Physical layer standard, the Protocol layer standard, the net management standard, the Communication layer standard and the Diagnostic layer standard. These standards have established main parameter and many other important schemes for the FlexRay bus. The modules which are developed based on these standards can communicate on the same FlexRay bus with no error. We are developing the central gateway module which can transmit the signals from CAN bus to FlexRay bus, these signals contain the cycle signals the diagnostic signals and the programming signals. Use the gateway, we can diagnostic and programming the FlexRay modules through the CAN bus. Limitations of this study. We are now designing the entire system and the central gateway module, we have not enough FlexRay modules to do the network testing. We have to use the diagnostic equipment to simulate the entire network. What does the paper offer that is new in the field in comparison to other works of the author: Only few vehicles use FlexRay bus. We will develop a low cost and feasible architecture and network strategy to apply the FlexRay bus in the vehicle. Conclusion: Although the FlexRay bus is complex bus, we still can find a low cost and feasible way to apply the bus in the vehicle.

F2012-D02-033