A novel spherical joint designed for metamorphic mechanism

A novel design of passive spherical metamorphic joint is proposed in this paper, the special mechanism of this design allows multi links to be connected together to do spherical motion about a rotation center. The main contribution of the joint design is the offset parallelogram mechanism and a couple door joints, which can overcomes efficiently the inherent defect from the conventional spherical joint design where a spherical joint can only connect two links simultaneously to do the motion. With this novel joint, we construct a kind of special six-bar spherical metamorphic mechanism. It is also explained how to do the configuration analysis, and to find the adjacency matrix of the metamorphic mechanism. According to the characteristic of the joint, some typical applications have been illustrated through parallel and variable geometry truss manipulators