Mapping synergies from human to robotic hands with dissimilar kinematics: an object based approach

Abstract

Abstract—One of the major limitations to the use of advanced robotic hands in industries is the complexity of the control system design due to the large number of motors needed to actuate their degrees of freedom (DoFs). It is our belief that the development of a unified control framework for robotic hands will allow to extend the use of these devices in many areas. Borrowing the terminology from software engineering, there is a need for middleware solutions to control the robotic hands independently from their specific kinematics, and focusing only on the manipulation tasks. To simplify and generalize the control of robotic hands we take inspiration from studies in neuroscience concerning the sensorimotor organization of the human hand. These studies demonstrated that, notwithstanding the complexity of the hand, a few variables are able to account for most of the variance in the patterns of configurations and movements. The reduced set of parameters that humans effectively use to control their hands, known in the literature as synergies, can represent the set of words for the unified control language of robotic hands provided that we solve the problem of mapping human hand synergies to actions of the robotic hands. In this work we propose a mapping designed in the manipulated object domain in order to ensure a high level of generality with respect to the many dissimilar kinematics of robotic hands. The role of the object is played by a virtual sphere, whose radius and center position change dynamically, and the role of the human hand is played by a hand model referred to as “paradigmatic hand,” able to capture the idea of synergies in human hands. Index Terms—Robotic grasping, sensory and motor human hand synergies, dexterous robotic hands, human skill transfer.