Voting with Dynamic Threshold Values for Real-time Fault Tolerant Control Systems

Voting on the outputs of redundant modules with real number results (i.e., where correctly functioning redundant systems may arrive at slightly different yet correct outputs for identical inputs) is not straightforward. Such cases need inexact voting in which some discrepancies between the outputs of redundant modules are allowed. Documented inexact voters use a fixed threshold value that may cause problems in safety-critical systems. This paper introduces a voting algorithm with dynamic threshold value. The voter is implemented, and compared with its counterpart with a fixed threshold value. The experimental results show that the novel voter gives more correct yet less incorrect results than the conventional majority voter with a fixed threshold value in the examined error scenarios. Copyright © 2005 IFAC