A GA-heuristic For Frame Packing Of Automotive FlexRay Static Segment

Automobile is a huge distributed control system. According to the functional requirements of the system, different communication protocols are used to exchange data. Among them, the most important three kinds of communication protocols are: CAN bus, LIN bus and Flex Ray bus. Flex Ray bus protocol is a new generation of vehicular communication protocol in order to s olve the problem of low communication rate and poor reliability of CAN bus. The Flex Ray protocol is a hybrid protocol, which has both the accuracy of the time triggered protocol, and the flexibility of the event based protocol. At the same time, it also has up to 10Mbit/s baud rate, which makes it can also be used to transmission of communication speed and accuracy have high requirements of t he control system of the signal.Because of the limited network resources of Flex Ray network, it is very important to reduce the use of Static Slot in the design of the vehicle control system. During the transmission of the static segment of Flex Ray, each node needs to be in accordance with the schedule table.Combined with task scheduling theory and Flex Ray static segment scheduling theory, the mathematical model and the object function has been formed. Residual Effective Bandwidth Ratio(E) has been proposed for performance metrics. Case study shows that residual effective bandwidth ratio can evaluate the multi-cycle Flex Ray static segment scheduling better than bandwidth utilization.The LBFP algorithm and hybrid GA(genetic algorithm)-LBFP(left best fit priority) algorithm have been presented to optimize static slots allocation and effective bandwidth ratio. AUTOSAR st andard for Flex Ray has been considered. The signal test results show that the two algorithms can both minimize the used static slots and improve the scalability of the static slot, LBFP-GA may perform better in improving the scalability and the static slot than LBFP, but LBFP seems to perform more effective than LBFP.An automobile network test platform has been designed for further study of the actual transmission characteristics of Flex Ray, TTCAN and LIN. ISO26222, the safety standards of automotive elect ronics, has been considered in the design process.