Schedulability Analysis For Messages Of CAN/FlexRay Networks Interconnected By A Gateway

With the rapid development of automotive electronic technology and communications control technology,fieldbus technology becomes more widely used in automotive networks.However,there is still no a communication network can fully meet all requirements of future vehicles in terms of cost and performance so far.Therefore,the automobile will be a multi-protocol architecture network in the future.CAN bus is the current mainstream vehicle network protocol,is widely used in automotive electronic control systems.FlexRay bus is the next generation of new bus standard,it has a high-speed,high reliability,flexibility,and other characteristics,it can satisfy the strong real-time requirements of modern automotive vehicle control systems,and can be used in automotive networks of high reliability and high security systems,such as power control systems,brake control systems.In the next generation of modern vehicles,the CAN/FlexRay mixed network will be more and more widely used in vehicles,Schedulability analysis of such mixed network is very important,but the schedulability analysis of CAN/FlexRay mixed network has not been extensive and in-depth research in the current.This paper focuses on CAN/FlexRay mixed network,a formal schedulability analysis for messages of CAN/FlexRay mixed network is proposed.The main work is as follows:First,a model analysis for CAN/FlexRay mixed network,Since the CAN and FlexRay vehicle bus communication mechanism is completely different,the protocol conversion need through a gateway for interconnection?This paper from the two levels of hardware and software analysis CAN / FlexRay hybrid system architecture,and gives the hardware and software structure diagram,special focuses on the analysis two particular network protocol format message mapping.Secondly,the formally worst response time analysis of various types messages in this hybrid network has been proposed,Due to the added gateway and the FlexRay network dynamic segment mechanism make it difficult to analyze the situation to find the worst response time of target messages,To solve the problem this paper presents an exhaustive searching algorithm to exhaustive out all gateway combination package message to find which will cause the worst-case response time to the target messages.Because the exhaustive searching algorithm is difficult within an acceptable time period to calculate the worst-case response message in the large message set,then a simplified searching MAX-MIN algorithm used to quickly determine the impact of the worst kind of message to the target messages,The algorithm takes into account only caused the worst impact on the next round of a round bale case,ignoring the situation is not the worst packaging in this round.Finally,Based on the simulation message set and the real message set provided by automobile manufacturers,this paper design experiments to verify the exhaustive search algorithm and simplified MAX-MIN algorithm,and the experimental results were analyzed,results showed that within an acceptable period of time,MAX-MIN algorithm in large-scale message set under good performance.But there are many deficiencies,need further study more optimized algorithms.