Hopping movement simulation of elastic actuator

Han, Yang; Shan-an, Zhu; Shi, Yu; Dabin, Hao; Zhongxiang, Xi; Wei, Zhuo.

doi:10.1109/icma.2015.7237828

Cited by 1 publication

(1 citation statement)

References 14 publications

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“…Clutches can be used in hybrid actuation schemes where springs or actuators are engaged individually, in parallel, or in series for improved performance [3,4]. These approaches can lead to lower energy use in bipedal robots [5,6], lowerlimb exoskeletons [7][8][9], and lower-limb prostheses [10,11], and suggest other devices that could assist gait [12,13].…”

Section: Introductionmentioning

confidence: 99%

A lightweight, low-power electroadhesive clutch and spring for exoskeleton actuation

Diller

Majidi

Collins

2016

2016 IEEE International Conference on Robotics and Automation (ICRA)

105

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Clutches can be used to enhance the functionality of springs or actuators in robotic devices. Here we describe a lightweight, low-power clutch used to control spring engagement in an ankle exoskeleton. The clutch is based on electrostatic adhesion between thin electrode sheets coated with a dielectric material. Each electrode pair weighs 1.5 g, bears up to 100 N, and changes states in less than 30 ms. We placed clutches in series with elastomer springs to allow control of spring engagement, and placed several clutched springs in parallel to discretely adjust stiffness. By engaging different numbers of springs, the system produced six different levels of stiffness. Force at peak displacement ranged from 14 to 501 N, and the device returned 95% of stored mechanical energy. Each clutched spring element weighed 26 g. We attached one clutched spring to an ankle exoskeleton and used it to engage the spring only while the foot was on the ground during 150 consecutive walking steps. Peak torque was 7.3 N·m on an average step, and the device consumed 0.6 mW of electricity. Compared to other electrically-controllable clutches, this approach results in three times higher torque density and two orders of magnitude lower power consumption per unit torque. We anticipate this technology will be incorporated into exoskeletons that tune stiffness online and into new actuator designs that utilize many lightweight, lowpower clutches acting in concert.

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