On the numerical classification of the singularities of robot manipulators

Conference Article


ASME International Design Engineering Technical Conference (IDETC)





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This paper is concerned with the task to obtain a complete description of the singularity set of any given non-redundant manipulator, including the identification and the precise computation of each constituent singularity class. Configurations belonging to the same class are equivalent in terms of the various types of kinematic and static degeneracy that characterize mechanism singularity. The proposed approach is an extension of recent work on computing singularities using a numerical method based on linear relaxations. Classification is sought by means of a hierarchy of singularity tests, each formulated as a system of quadratic or linear equations, which yields sets of classes to which an identified singularity cannot belong. A planar manipulator exemplifies the process of classification, and illustrates how, while most singularities get completely classified, for some lower-dimensional subsets one can only identify a restricted list

of possible singularity classes.


manipulators, robot kinematics.

Author keywords

singularities, branch-and-prune method, linear relaxation, classification

Scientific reference

O. Bohigas, D. Zlatanov, M. Manubens and L. Ros. On the numerical classification of the singularities of robot manipulators, 2012 ASME International Design Engineering Technical Conference, 2012, Chicago, Illinois, USA, pp. 1287-1296.