Extension of the form-closure property to underactuated hands

Authors:
Sébastien Krut;Vincent Bégoc;Etienne Dombre;François Pierrot
Affiliations:
Montpellier Laboratory of Informatics, Robotics, and Microelectronics, French National Center for Scientific Research, Montpellier University of Sciences, Montpellier Cedex, France;B+ Equipment, Gemenos, France.;Montpellier Laboratory of Informatics, Robotics, and Microelectronics, French National Center for Scientific Research, Montpellier University of Sciences, Montpellier Cedex, France;Montpellier Laboratory of Informatics, Robotics, and Microelectronics, French National Center for Scientific Research, Montpellier University of Sciences, Montpellier Cedex, France
Venue:
IEEE Transactions on Robotics
Year:
2010

Citing 7
Cited 0

The Geometry of grasping

International Journal of Robotics Research
On the closure properties of robotic grasping

International Journal of Robotics Research
On computing four-finger equilibrium and force-closure grasps of polyhedral objects

International Journal of Robotics Research
Robonaut: NASA's Space Humanoid

IEEE Intelligent Systems
The SPRING Hand: Development of a Self-Adaptive Prosthesis for Restoring Natural Grasping

Autonomous Robots
Force Analysis of Connected Differential Mechanisms: Application to Grasping

International Journal of Robotics Research
Underactuated Robotic Hands

Underactuated Robotic Hands

Quantified Score

Hi-index	0.00

Visualization

Abstract

The property of form-closure of a grasp, as generally defined in the literature, is based on the assumption that contact points between the hand and the object are fixed in space. However, this assumption is false when considering a grasp exerted by an underactuated hand, since, in this case, it is not possible to control the position of each phalanx independently. In spite of researchers' interest in studying form-closure, none of the available published work on this subject takes into consideration the particular kinematics of underactuated hands. Actually, there are few available tools to qualify or quantify the stability of a grasp exerted by an underactuated hand; thus, the design of underactuated hands mostly results from an intuitive approach. This paper aims to reduce this gap. A classification of underactuated hands is proposed, which is based on the expression of contact forces. This highlights the influence of nonbackdrivable mechanisms introduced in the transmission of the closing motion of the hand on the stability of the grasp. After demonstrating that the original definition of form-closure is not suitable for the underactuated grasps, a more general definition is formulated, which checks the stability of the assembly "object + hand." Using this new definition, a geometric method is proposed for the analysis of first-order form-closure of an underactuated grasp, as well as a simple rule to design a hand capable of achieving first-order form-closed grasps. Finally, amethod is proposed for the analysis of higher order formclosure of an underactuated grasp, which is based on a first-order model of the grasp.