Singularity analysis and performance indexes for parallel manipulators

The performance indexes are commonly based on the Jacobian Matrix, and they have been commonly used in determining the dexterous regions of a manipulator workspace. Many performance indexes have been studied so far for the kinematic behavior analysis of serial manipulators, and most of them can be applied to the parallel ones too. The Manipulability Index, the Minimum Singular Value and the Reverse of the Condition Number give information about the presence of points of singularity in the manipulator workspace. In the first part of the paper, the attention is focused in the problem of the singularity analysis of the parallel manipulators by means of the most commonly used performance indexes. A manipulator with three degrees of freedom will be used as a testbed for this analysis. In the second part, the paper deals with novel performance indexes that have the property of giving information even in the points of singularity of the manipulator workspace.