Open AccessDesign and Characterization of a Novel High-Power Series Elastic Actuator for a Lower Limb Robotic Orthosis
Author(s) -
Dino Accoto,
Giorgio Carpino,
Fabrizio Sergi,
Nevio Luigi Tagliamonte,
Loredana Zollo,
Eugenio Guglielmelli
Publication year - 2013
Publication title -
international journal of advanced robotic systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 46
eISSN - 1729-8814
pISSN - 1729-8806
DOI - 10.5772/56927
Subject(s) - actuator , torque , computer science , torsion spring , rehabilitation robotics , stiffness , robot , deflection (physics) , rotary actuator , wearable computer , robotics , control theory (sociology) , simulation , mechanical engineering , artificial intelligence , physics , engineering , control (management) , embedded system , optics , thermodynamics
A safe interaction is crucial in wearable robotics in general, while in assistive and rehabilitation applications, robots may also be required to minimally perturb physiological movements, ideally acting as perfectly transparent machines. The actuation system plays a central role because the expected performance, in terms of torque, speed and control bandwidth, must not be achieved at the expense of lightness and compactness. Actuators embedding compliant elements, such as series elastic actuators, can be designed to meet the above-mentioned requirements in terms of high energy storing capacity and stability of torque control. A number of series elastic actuators have been proposed over the past 20 years in order to accommodate the needs arising from specific applications. This paper presents a novel series elastic actuator intended for the actuation system of a lower limb wearable robot, recently developed in our lab. The actuator is able to deliver 300 W and has a novel architecture making its centre of mass not co-located with its axis of rotation, for an easier integration into the robotic structure. A custom-made torsion spring with a stiffness of 272.25 N·m·rad–1 is directly connected to the load. The delivered torque is calculated from the measurement of the spring deflection, through two absolute encoders. Testing on torque measurement accuracy and torque/stiffness control are reported