The Research And Implementation Of Scheduling Algorithm In Passenger Vehicle Network Control System

With the rapid development and the widely application of automotive electronics and network control technology, the car of the real time network control system, passenger car communication data security problem and broadcast scheduling problem has become a research hotspot and difficulty. Because of car driving requirements and capabilities continue to increase, improve urban environmental awareness and a series of factors reinforce passenger security requirements, making the existing automotive electrical and electronic platform, network control platform made more stringent and more demanding, so there are more and more automotive electrical controllers, network more complex, the amount of information to work with each other is also growing, the speed become faster and faster, the degree of coupling between them has become increasingly tight, it brings a large amount of information and electronic platform information data, network information delay, system control performance and a series of problems, and then causing the uncertainty of the security and stability of the vehicle driving. Therefore, need to adopt some new analysis methods and new design ideas to design the auto control network system, adopting new scheduling strategy to reduce the possibility of network time delay, thus improving the overall performance automotive network control system to achieve and meet the new requirements for motorists.This paper mainly uses the method from theory to practice to verify the system for research.From start modeling, simulation theory to the practical application of design and analysis, and then to the experimental bench validation steps, such as delay of passenger car network control system, scheduling problems, and clock synchronization problem carried on the thorough analysis and research.First of all, the thesis summarizes the characteristics of passenger car network control system, emphatically analyses the existing problems, the system and the system time delay and scheduling problems existing in the research progress on the tracking and analysis.Secondly, in the passenger car network control system, on the basis of the existing mathematical model, and the typical network scheduling algorithm is adopted to network communication performance are analyzed, and find out the key factors influencing the network communication time delay and scheduling. ①The periodic message delay in CAN network, this paper proposes a static priority scheduling algorithm based on the network nodes.Scheduling algorithm on the basis of the algorithm in the monotonous rate, through the analysis of the priority of network nodes and the message cycle, the relationship between the most communication latency time points, the variables and the moment as the delay is introduced into the mathematical model, which can accurately estimate the situation of network node time delay, time delay reduces the network news.The vehicle network platform verification results show that the proposed algorithm effectively reduces the network time delay, improve the overall performance of the system.②For the event of network management class packets in CAN network, we propose a flexible dynamic scheduling algorithm. The algorithm proposed the concept of flexible coefficient coefficient as the weighting factor network packet cycle, according to the network bandwidth dynamically assign weights to reduce the possibility of network congestion, thus improving the utilization of network bandwidth. Vehicle network platform validation results show that the flexible dynamic scheduling algorithm proposed in enhancing the stability of the network, and effectively improve the communication performance of the network at the same time.③Surface under future passenger car based in Flexray networks, this paper proposes a scheduling algorithm based on clock compensation on Flexray network. According to the characteristics of new passenger cars network control system, based on the existing scheduling algorithms, and the size of the clock compensation, a reasonable allocation of time slots on the static and dynamic segment segment different slot control strategy to Increase network bandwidth utilization, improved Flexray network communication performance.Finally, according to the actual needs of automotive electrical and electronic platform,verification platform of passenger vehicle-level network control system is built. Design and implement a passenger vehicle-level network control system to research and testing platform, which is a HIL (Hardware In Loop) system that can fully simulate the vehicle electrical and electronic logic control process, having multiplied car network control system platform capability to analysis and testing. At the same time,The platform has verified the static scheduling algorithm, the flexible dynamic scheduling algorithm and Scheduling algorithm based on clock compensation Flexray clock proposed above, verification results shows that the proposed algorithm effectively reduces network latency occurs, enhances network stability, improve the communication performance of the network, improves the performance of vehicle-level network system, effectively reduces the possibility of network latency, thereby improving the safety and stability for driving control of passenger cars.