Upper Limb Deweighting Using Underactuated End-Effector-Based Backdrivable Manipulanda

Abstract

In rehabilitation for neurological injuries, gravity compensation or deweighting of the upper limb is often performed, as it allows patients with limited muscle activities to realize movements. Deweighting cancels the gravitational effect of the human arm allowing the available muscle forces to produce acceleration, and thus movement of the arm. In robotic devices designed for rehabilitation, deweighting is performed by applying forces to the arm, either joint-by-joint (e.g., with exoskeletons) or at a single point (e.g., with end-effector-based manipulanda). This paper formulates the gravity compensation strategy for spatial (three-dimensional) manipulanda, considers the effect of the force..