Kinematics of the (nS)-2SPU Wrist Available to Purchase

The majority of the manipulation tasks requires the motion of the end effector from an initial pose to a final one without particular conditions on the path. Thus, the reduction of the practicable paths between two any poses is a possible choice, exploitable at the design stage, for simplifying manipulator’s hardware. This choice is adopted in under-actuated manipulators. The (nS)-2SPU wrist is one out of the under-actuated parallel wrists this author proposed in a previous paper. Here, the kinematic analysis of this wrist is studied. Both its finite and its elementary kinematics are considered. It is shown that its control algorithms can be written by using simple closed-form formulas, which can take advantage from the wide literature on spherical four-bar linkages. And the demonstration that its singular configurations can be avoided more easily than the ones of the fully-parallel wrist is provided.