The control number as index for Stewart Gough platforms

Abstract

Singular postures of Stewart Gough Platforms must be avoided because close to singularities they lose controllable degrees of freedom. Hence there is an interest in a distance measure between the instantaneous configuration and the nearest singularity. This article presents such a measure, which is invariant under Euclidean motions and similarities, which has a geometric meaning and can be computed in real-time. This measure ranging between 0 and 1 can serve as a performance index.