Variable-friction finger surfaces to enable within-hand manipulation via gripping and sliding
File(s)Spiers - Friction Finger RA-L - Camera Ready.pdf (1.53 MB)
Accepted version
Author(s)
Spiers, Adam J
Calli, Berk
Dollar, Aaron M
Type
Journal Article
Abstract
The human hand is able to achieve an unparalleled diversity of manipulation actions. One contributor to this capability is the structure of the human finger pad, where soft internal tissue is surrounded by a layer of more rigid skin. This permits conforming of the finger pad around object contours for firm grasping, while also permitting low-friction sliding over object surfaces with a light touch. These varying modes of manipulation contribute to the common ability for in-hand-manipulation, where an object (such as a car key) may repositioned relative to the palm. In this letter, we present a simple mechanical analogy to the human finger pad, via a robotic finger with both high- and low-friction surfaces. The low-friction surface is suspended on elastic elements and recesses into a cavity when a sufficient normal force is applied (~1.2 to 2.5 N depending on contact location), exposing the high-friction surface. We implement one “variable friction” finger and one “constant friction” finger on a 2-DOF gripper with a simple torque controller. With this setup, we demonstrate how within-hand rolling and sliding of an object may be achieved without the need for tactile sensing, high-dexterity, dynamic finger/object modeling, or complex control methods. The addition of an actuator to the finger design allows controlled switching between variable-friction and constant-friction modes, enabling precise object translation and reorientation within a grasp, via simple motion sequences. The rolling and sliding behaviors are characterized with experimentally verified geometric models.
Date Issued
2018-10-01
Date Acceptance
2018-06-24
Citation
IEEE Robotics and Automation Letters, 2018, 3 (4), pp.4116-4123
ISSN
2377-3766
Publisher
Institute of Electrical and Electronics Engineers
Start Page
4116
End Page
4123
Journal / Book Title
IEEE Robotics and Automation Letters
Volume
3
Issue
4
Copyright Statement
© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Identifier
https://ieeexplore.ieee.org/document/8411094
Subjects
0913 Mechanical Engineering
Publication Status
Published
Date Publish Online
2018-07-16