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Actuators 2014, 3(2), 20-40; doi:10.3390/act3020020

A Two-Degree of Freedom Variable Stiffness Actuator Based on the MACCEPA Concept

* ,
Department of Mechanical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, Elsene 1050, Belgium
* Author to whom correspondence should be addressed.
Received: 30 December 2013 / Revised: 25 March 2014 / Accepted: 26 March 2014 / Published: 3 April 2014
(This article belongs to the Special Issue Soft Actuators)
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The current state-of-the-art of variable stiffness actuators consists mostly of different concepts for single-degree of freedom joints. However, in bio-inspired robotic applications, multiple degrees of freedom variable stiffness actuators are often desired. Currently, this is usually achieved by cascading single-degree of freedom actuators. The innovation presented in this work is a two-degree of freedom variable stiffness actuator using the mechanically adjustable and controllable equilibrium position actuator (MACCEPA) concept. The presented actuator is not a cascade of two single-degree of freedom actuators, but centralizes the two degrees of freedom in one single joint. Equilibrium position and stiffness of the actuator are, furthermore, independently controllable in both degrees of freedom. The design and experimental validation of the actuator are discussed in this work. The independence of adjusting the equilibrium position and stiffness of the actuator are experimentally validated. The results show that the measured characteristics of the actuator sufficiently match the theoretically calculated ones. Future work includes implementing the presented two-degree of freedom actuator in an application, like a bipedal robot or a robotic arm.
Keywords: compliant actuator; variable stiffness; two degrees of freedom; MACCEPA compliant actuator; variable stiffness; two degrees of freedom; MACCEPA
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

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Weckx, M.; Mathijssen, G.; Si Mhand Benali, I.; Furnemont, R.; Van Ham, R.; Lefeber, D.; Vanderborght, B. A Two-Degree of Freedom Variable Stiffness Actuator Based on the MACCEPA Concept. Actuators 2014, 3, 20-40.

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