Towards a Myoelectric Prosthetic Wrist with Rigid and Compliant Behaviour

The simple kinematics of commercial prosthetic wrists limits the individuals in performing a wide range of tasks and restore natural motor functions. We propose a functional prosthesis that improves grasping capabilities through the addition of a simple yet useful 3 DoF myoelectric wrist joint with compliant and rigid properties. Its locking capability enables the adjustment of hand configuration in pre-grasping phases and separates the hand motion from the wrist motion. The proposed wrist, combined with a prosthetic hand, was tested with 8 able-bodied subjects and 1 subject with limb loss. It was compared to a common commercial rotational wrist and to subjects’ natural wrist. Results evidence the feasibility of the prototype, improved performance capabilities, and the subjects’ first impression about the proposed system. Finally, a prosthesis user tested and compared systems during Activities of Daily Living (ADL).