An Integrated Voting Algorithm for Fault Tolerant Systems

Fault masking is one of the primary approaches to improve or maintain the normal behaviour of a range of safety-critical systems. Some industrial sectors which employ such systems include process control, transportation, nuclear power station and military applications. Majority and weighted average voters have been widely used in these applications to provide error/fault-masking capability. The former gives a good level of safety and the latter offers a good level of availability. This paper introduces a novel voter that integrates the majority and standard weighted average voters. It is an appropriate substitute for the weighted average voter. An experimental framework for evaluating software voting algorithms is provided and safety/availability behaviour of the proposed voter is studied in various error scenarios. The experimental results show that in all scenarios the integrated voter gives a higher availability than both the majority and weighted average voters. However, it has compromise safety behaviour between the majority and weighted average voters. It also performs faster than the naive weighted average voter does.