Research On Real-time Scheduling Algorithm For Time-triggered Can Systematic Matrix With Fault-tolerant Model

The traditional CAN is based on event-triggered mechanism. It has some disadvantages, such as load limit, real-time performance and multi-processor conflict. In order to solve those problems, BOSCH Company introduces TTCAN,which is a combination of time-triggered and event-triggered mechanism. TTCAN is extensions of CAN, which improves the real-time performance of the network and makes the communication not only meeting the demand of security critical real-time system but also increasing bus load.Since TTCAN is based on time-triggered, it will inevitably lead to the scheduling problems of messages.This paper researches on real-time scheduling problem based TTCAN. The first step, it introduces what TTCAN is and some of key technologies about TTCAN which can help people clearly understand the problem statement and optimization. After that, according to the set of messages, system matrix is constituted. Genetic algorithm is used for optimization that aims to minimize the time of exclusive window. Largest Common Denominator (GCD) algorithms are taken advantage of solving the scheduling problem which message set is not satisfied with the constraints of TTCAN.Then, it focuses on studying and designing the fault-tolerant model of system matrix. This paper uses the arbitration window fault-tolerant technology to design system matrix. Meanwhile, it also takes advantage of forward latter priority principle for arbitration window fault-tolerant model.At last, the author take two classic message sets SAE and PSA as examples, combine of genetic algorithm and the GCD algorithm in order to validate the scheduling algorithm for system matrix.The experimental results prove that the algorithm we proposed has the advantage of real-time transmission of signal and bandwidth utilization ratio, and also enhance the flexibility of practical application effectively in TTCAN protocl.In addition, fault-tolerant greatly reduces the failure rate of messages transmission. Finally, the successful establishment of model provides an important reference value for TTCAN protocol which is applied in the hard real-time communication environment that requiring higher communication reliability.