Towards simplicity: On the design of a 2-DOFs wrist mechanism for tendon-driven robotic hands

In this paper, a novel approach for simplifying the design, the prototyping and the assembly of a wrist mechanism with 2 DOFs for anthropomorphic tendon-driven robotic hands is presented. This novel design concept allows a relevant reduction of both the number of parts and their manufacturing complexity, guaranteeing at the same time the decoupling of the fingers and the wrist motion by means of a particular choice of tendons routing. The simplification of the mechanism is achieved with the partial drawback of introducing additional friction forces along the tendons, which are however compensated by the control and do not significantly affect the overall behavior of the hand. The proposed wrist design has been adopted in the development of th UB-Hand IV.