A compact soft articulated parallel wrist for grasping in narrow spaces

The increasing presence of high density logistic warehouses demands the deployment of fast and flexible robotic solutions. One of the open challenges toward this objective is manipulation in narrow settings. This work addresses such a problem from a design perspective. By observing human arm dexterity and grasp strategies, the role of the wrist emerges as fundamental in providing both a large workspace and a minimal clearance. We compare the kinematic envelope of robotic manipulators wrist to their human counterpart through the introduction of the reversed workspace, defined as the volume required by a kinematic chain for a set of end-effector orientations. Results suggest to combine the properties of serial and parallel architectures, to obtain a suitable tradeoff between compactness and workspace. On this base, we present a novel soft articulated parallel wrist device that can be easily interfaced with industrial off-the-shelf manipulators to enhance their manipulation capabilities in constrained environments.