Physical constraints, fundamental limits, and optimal locus of operating points for an inverted pendulum based actuated dynamic walker

Patnaik, Lalit and Umanand, Loganathan (2015) Physical constraints, fundamental limits, and optimal locus of operating points for an inverted pendulum based actuated dynamic walker. In: BIOINSPIRATION & BIOMIMETICS, 10 (6).

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Abstract

The inverted pendulum is a popular model for describing bipedal dynamic walking. The operating point of the walker can be specified by the combination of initial mid-stance velocity (v(0)) and step angle (phi(m)) chosen for a given walk. In this paper, using basic mechanics, a framework of physical constraints that limit the choice of operating points is proposed. The constraint lines thus obtained delimit the allowable region of operation of the walker in the v(0)-phi(m) plane. A given average forward velocity v(x,) (avg) can be achieved by several combinations of v(0) and phi(m). Only one of these combinations results in the minimum mechanical power consumption and can be considered the optimum operating point for the given v(x, avg). This paper proposes a method for obtaining this optimal operating point based on tangency of the power and velocity contours. Putting together all such operating points for various v(x, avg,) a family of optimum operating points, called the optimal locus, is obtained. For the energy loss and internal energy models chosen, the optimal locus obtained has a largely constant step angle with increasing speed but tapers off at non-dimensional speeds close to unity.

Item Type:	Journal Article
Publication:	BIOINSPIRATION & BIOMIMETICS
Publisher:	IOP PUBLISHING LTD
Additional Information:	Copy right for this article belongs to the IOP PUBLISHING LTD, TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND
Keywords:	inverted pendulum; constraints on walking; optimal walker
Department/Centre:	Division of Electrical Sciences > Electronic Systems Engineering (Formerly Centre for Electronic Design & Technology)
Date Deposited:	20 Jan 2016 05:47
Last Modified:	20 Jan 2016 05:47
URI:	http://eprints.iisc.ac.in/id/eprint/53146

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