Spring uses in exoskeleton actuation design

An exoskeleton has to be lightweight, compliant, yet powerful to fulfill the demanding task of walking. This imposes a great challenge for the actuator design. Electric motors, by far the most common actuator in robotic, orthotic, and prosthetic devices, cannot provide sufficiently high peak and ave...

Full description

Saved in:
Bibliographic Details
Main Authors: Shiqian Wang, van Dijk, W., van der Kooij, H.
Format: Conference Proceeding
Language:English
Subjects:
actuation
Adult
Ankle Joint - physiology
Biomechanical Phenomena
exoskeleton
Exoskeletons
Female
Gait - physiology
Gears
Hip
Humans
Joints
Legged locomotion
Male
Muscle, Skeletal - physiology
Orthotic Devices
PEA
Robotics - instrumentation
Robotics - methods
SEA
Spinal Cord Injuries - rehabilitation
spring
Springs
Torque
Walking - physiology
wearable robots
Young Adult
Citations: Items that cite this one
Online Access:Request full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:An exoskeleton has to be lightweight, compliant, yet powerful to fulfill the demanding task of walking. This imposes a great challenge for the actuator design. Electric motors, by far the most common actuator in robotic, orthotic, and prosthetic devices, cannot provide sufficiently high peak and average power and force/torque output, and they normally require high-ratio, heavy reducer to produce the speeds and high torques needed for human locomotion. Studies on the human muscle-tendon system have shown that muscles (including tendons and ligaments) function as a spring, and by storing energy and releasing it at a proper moment, locomotion becomes more energy efficient. Inspired by the muscle behavior, we propose a novel actuation strategy for exoskeleton design. In this paper, the collected gait data are analyzed to identify the spring property of the human muscle-tendon system. Theoretical optimization results show that adding parallel springs can reduce the peak torque by 66%, 53%, and 48% for hip flexion/extension (F/E), hip abduction/adduction (A/A), and ankle dorsi/plantar flexion (D/PF), respectively, and the rms power by 50%, 45%, and 61%, respectively. Adding a series spring (forming a Series Elastic Actuator, SEA) reduces the peak power by 79% for ankle D/PF, and by 60% for hip A/A. A SEA does not reduce the peak power demand at other joints. The optimization approach can be used for designing other wearable robots as well.
ISSN:1945-7898
1945-7901
DOI:10.1109/ICORR.2011.5975471