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Actuators 2017, 6(3), 22;

A Novel Mechanically Overdamped Actuator with Adjustable Stiffness (MOD-AwAS) for Safe Interaction and Accurate Positioning

Department of Mechanical Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
Advanced Robotic Manipulators (ARM) Lab, Department of Mechanical Engineering, University of Texas at San Antonio (UTSA), One Circle, San Antonio, TX 78249, USA
Author to whom correspondence should be addressed.
Received: 23 May 2017 / Revised: 16 June 2017 / Accepted: 19 June 2017 / Published: 28 June 2017
(This article belongs to the Special Issue Variable Stiffness and Variable Impedance Actuators)
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This paper presents the design and development of a novel mechanically overdamped actuator with adjustable stiffness (MOD-AwAS). The novelty of MOD-AwAS compared to other variable stiffness actuators relates to its mechanical design, which prevents oscillations at the output link. Almost all variable stiffness actuators have an overshooting problem that require a sophisticated control algorithm to be able to perform accurate positioning. MOD-AwAS can regulate the stiffness from zero to its maximum (theoretically infinite) in less than 0.2 s by changing the position of the pivot point of its lever mechanisms. MOD-AwAS employs only one rotational spring with no pre-deflection, which gives it full accessibility to its energy storage capacity. Experimental results are presented to show the ability of MOD-AwAS to control its position accurately with a wide range of stiffness adjustment. View Full-Text
Keywords: variable stiffness; overdamped system; energy storage variable stiffness; overdamped system; energy storage

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Lee, J.H.; Wahrmund, C.; Jafari, A. A Novel Mechanically Overdamped Actuator with Adjustable Stiffness (MOD-AwAS) for Safe Interaction and Accurate Positioning. Actuators 2017, 6, 22.

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