Voting Algorithms in Multiple Error Scenarios for Real-time Control Applications

Voting algorithms are used to arbitrate between the results of variants in fault-tolerant systems. Industrial sectors which employ such systems include process control, transportation (such as railway and avionics), nuclear power plants, and military applications. Typical voters used in fault tolerant systems are majority, plurality, median, and weighted average. These voters can produce either no result (benign output) or an incorrect output when multiple simultaneous errors, related or unrelated, occur in a voting cycle. The majority and plurality voters produce a ‘no-result’ (an exception code) in disagreement cases. Such an output moves the system toward a safe-fail or safe-stop state and is regarded as a ‘benign output’. The median voter and the weighted average voter give an incorrect output in the case of multiple error conditions.