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Proceedings Paper

Improving energy efficiency in robot limbs through hydraulic dangle
Author(s): Julian S. Whitman; Mike Meller; Ephrahim Garcia
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Paper Abstract

Animals often allow their limbs to swing passively under their own inertia. For example, about 40% of a human walking gait consists of the primarily passive swing phase. Current hydraulic robots employ traditional actuation methods in which fluid power is expended for all limb movements, even when passive dynamics could be utilized. “Dangle” is the ability to allow a hydraulic actuator to freely sway in response to external loads, in which both sides of the actuator are disconnected from pressure and connected to the tank. Dangle offers the opportunity for efficiency gains by enabling the use of momentum, gravity, and external loads to move a limb without expending fluid power. To demonstrate these efficiency gains, this paper presents an experiment that compares the fluid power consumed to actuate a two degree of freedom hydraulic leg following a human walking gait cycle trajectory in both a traditional manner and utilizing dangle. It was shown that the use of dangle can decrease fluid power consumption by 20% by utilizing pendular dynamics during the swing phase. At speeds higher than the free dangling rate, more power must be used to maintain the desired trajectory due to damping inherent in the configuration. The use of dangle as a power saving method when driving hydraulic limbs could increase operation time for untethered hydraulic walking robots.

Paper Details

Date Published: 26 March 2015
PDF: 6 pages
Proc. SPIE 9429, Bioinspiration, Biomimetics, and Bioreplication 2015, 94291M (26 March 2015); doi: 10.1117/12.2175588
Show Author Affiliations
Julian S. Whitman, Cornell Univ. (United States)
Mike Meller, Cornell Univ. (United States)
Ephrahim Garcia, Cornell Univ. (United States)


Published in SPIE Proceedings Vol. 9429:
Bioinspiration, Biomimetics, and Bioreplication 2015
Akhlesh Lakhtakia; Mato Knez; Raúl J. Martín-Palma, Editor(s)

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