Component-oriented voter model for dependable control applications

Abstract

Control systems are required to meet increasingly stringent reliability and safety constraints. In many industrial applications arbitration between redundant subsystems using voting algorithms is popular. Many voting strategies, implemented in hardware or software, have been proposed of which only majority and median voters have been widely used in real applications. Detailed analysis of voters, shows that they can be considered as a combination of independent components, each performing a specific function. This paper proposes a component-oriented model for voters. Components and their families are introduced and categorised and component-oriented model of selected voters is constructed. The generality of the model supports the analysis of a large number of voter permutations. The paper presents five novel algorithms which combine the safety properties of the majority voter with the advantages of mid-value selection strategy.