The Research Of Task Scheduling Algorithm Based On CAN

CAN bus protocol was developed by BOSCH company, it was aimed to solve the problem between the electronic devices in the automotive electronics industry’s growing communication needs of network communication.Due to its good performance in the practical application process, since it has been received extensive attention of the industry is put forward and in-depth research. Nowadays, CAN protocol has become an attractive solution of distributed system due to its simplicity, low implementation and widespread availability. However, with the development of automotive electronics and the increase of ECU,the requirement of real-time performance is becoming more and more high-level; the drawback of the CAN has hindered its application. Therefore, the research of the scheduling algorithm based on CAN has an important significance for improving the performance of the system.This paper is focused on the scheduling algorithm of the CAN bus. Firstly, the feature and limitations of the CAN bus is pointed out, then the real-time problem of CAN bus communication is analyzed, and the importance of the scheduling algorithm is indicated. After the brief introduction of the scheduling algorithm, as the research emphasis, theshared-clock scheduling algorithm is introduced specifically.The CAN protocol is widely used in distributed embedded system.Early research has proved that shared-clock scheduling algorithm could be applied to CAN application layer to implement in time triggered architecture. In view of the shared-clock scheduling algorithms are used with time-triggered cooperative scheduler, they suffer some limitations, connected with the time-triggered hybrid scheduler, proposed a shared-clock hybrid scheduling algorithm.Then the failure detection time and jitter of the algorithm is analyzed. Finally simulation model is built by using Truetime toolbox; the experimental results indicate the superiority of the algorithm. It can improves the clock synchronization accuracy of the system, reduces the jitter, and hence strengthens the real-time character of the system.The research achievement of this paper indicates that the application of the improved algorithm which combined the original shared-clock scheduling algorithm with the time-triggered hybrid mechanism has the good behavior. The improved algorithm can reduces the transmission time of the tick message and the jitter of the whole system, while maintaining the high efficiency of the task on the node at thesame time. So the algorithm Has a certain practical application value.