Copyright © 2009 Nir Shvalb et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
We study singularities for a parallel mechanism with a planar moving
platform in , with joints which are universal, spherical (spatial case),
or rotational (planar case). For such mechanisms, we give a necessary condition
for a topological singularity to occur, and describe the corresponding kinematic
singularity. An example is provided.