Singularity Analysis of 2R1P Spherical Parallel Mechanisms

This paper studies the possible configurations and singularities of 3-DOF spherical parallel mechanisms with revolute and prismatic pairs. In particular, the 2R1P spherical parallel mechanisms are studied, for which the kinematic models are established and Jacobian matrices are derived. Three kinds of singularities, namely the boundary, configuration and structure singularities, are identified and analyzed for RRP, PRR and RPR type of spherical parallel mechanisms. The results can be used for further modeling and analysis on workspace and trajectory planning of 3-DOF spherical parallel mechanisms towards the practical application of the kind of mechanisms.