Title

The Arched Flexure VSA: A Compact Variable Stiffness Actuator with Large Stiffness Range

Document Type

Conference Proceeding

Language

eng

Format of Original

6 p.

Publication Date

5-26-2015

Publisher

Institute of Electrical and Electronics Engineers (IEEE)

Source Publication

2015 IEEE International Conference on Robotics and Automation (ICRA)

Source ISSN

1050-4729

Abstract

The high stiffness of conventional robots is beneficial in attaining highly accurate positioning in free space. High stiffness, however, limits a robot's ability to perform constrained manipulation. Because of the high stiffness, geometric conflict between the robot and task constraints during constrained manipulation can lead to excessive forces and task failure. Variable stiffness actuators can be used to adjust the stiffness of robot joints to allow high stiffness in unconstrained directions and low stiffness in constrained directions. Two important design criteria for variable stiffness actuation are a large range of stiffness and a compact size. A new design, the Arched Flexure VSA, uses a cantilevered beam flexure of variable cross-section and a controllable load location. It allows the joint to have continuously variable stiffness within a finite stiffness range, have zero stiffness for a small range of joint motion, and allow rapid adjustment of stiffness. Using finite element analysis, flexure geometry was optimized to achieve high stiffness in a compact size. A proof-of-concept prototype demonstrated continuously variable stiffness with a ratio of high stiffness to low stiffness of 55.

Comments

Published as part of the proceedings of the conference, 2015 IEEE International Conference on Robotics and Automation (ICRA), 2015: 220-225. DOI.