Abstract:

When the controller area network（CAN） bus is applied to a distributed overloading system,the reliability and real-time property of the system can not be guaranteed.Fault-tolerant algorithms are the important means to improve the system performances.In this paper,several fault-tolerant algorithms are analyzed and compared,and an approach of introducing active request and dynamic load distribution in the redundant services is proposed,based on which an effective fault-tolerant algorithm for CAN systems is put forward.In this algorithm,CAN nodes decide whether to actively request the task to be a redundant server according to their load status,and the management system assigns the load to each redundant server according to the load and the current status of node hosts and changes the number of redundant servers dynamically.A mathematical model of the proposed algorithm is also established,and some illustrations are finally presented to compare the algorithm with RAWA fault-tolerant algorithms.The results show that the proposed algorithm with high performance is applicable to the control system with high reliability and good real-time property.

Key words: fault tolerance, controller area network, dynamic load, active request