Optimum Design Of FlexRay Network For Pure Electric Vehicle

In order to meet the growing demand for safety,comfort,economy and environmental protection,cars are rapidly developing in the direction of electronics,networking and intelligence.The new generation of automotive electronic control systems has a more complex network structure,greater communication data volume,higher reliability requirements,faster function expansion speed,and traditional automotive networks are difficult to meet.FlexRay is a next-generation in-vehicle network protocol,and its functional security is very important.This article takes the reliability of the FlexRay network as the starting point.The main work is as follows:The FlexRay protocol has become the defactor standard for automotive communication systems,providing the advantages of event triggering and time-triggered paradigms.In order to minimize the bandwidth consumption(BC)in the static segment of the FlexRay communication cycle,we propose a frame packing algorithm called BC,which minimizes with various periodic signals(BCMVPS),which is formulated as a generalized integer.Linear programming allows signals to be packed into message frames at different times.We also propose the lower and upper bounds of the static slot size and provide a heuristic called BC best fit decrement for linear frame selection to reduce the computation time of the BCMVPS algorithm.We used the Society of Automotive Engineers benchmark data and the GNU Linear Programming Toolkit to compare the performance of the proposed algorithm with existing algorithms.The results show that the BC of the proposed algorithm is smaller than the existing frame encapsulation algorithm.We studied the scheduling of periodic messages in the static segment of the FlexRayprotocol.Our approach is based on two performance metrics.We seek to allocate a minimum number of frame IDs(FIDs)in the static segment.In addition,unlike existing work,we want to minimize message jitter,which is the deviation of message transmission from the required period.To this end,we first derive an analytical expression for quantifying FID allocation and jitter,and then formulate a linear integer programming problem whose solution is the required message scheduling.This article packs the signal into the frame of the application layer and then transmits the frame over the bus.In order to ensure the reliability of the frame in the event of a fault,the frame must be retransmitted over the bus,but at the expense of higher.bandwidth utilization.To solve this problem,this paper proposes a new FlexRay bus frame encapsulation method.Our method calculates the number of frame retransmissions required to ensure the specified reliability target.The proposed frame packing method also ensures that no signal violates its deadline and meets the desired reliability target for fault tolerance at a minimum bandwidth cost.