基于主动请求与动态分配负载的CAN容错算法

Fault-Tolerant Algorithm Based on Active Request and Dynamic Load Distribution for CAN System

控制器局部网(CAN)总线应用于负载较重的分布式系统时,系统的可靠性和实时性难以保证,容错算法是提高分布式系统容错性能的重要手段。文中通过对多种容错算法的分析比较,在冗余服务中引入主动请求与动态分配负载的思想,提出了一种有效的CAN冗余容错算法.CAN节点可根据自身的负载情况决定是否作为冗余服务器主动请求任务,管理系统综合考虑负载和节点主机的当前状况,动态分配负载给各冗余服务器,同时系统还可动态改变冗余服务器的个数.最后,构建了该算法的数学模型,与RAWA算法进行了对比,并通过实例证明该算法性能较好,可用于高可靠、高实时性的控制系统中.

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.