Research Papers

Homotopy Directed Optimization to Design a Six-Bar Linkage for a Lower Limb With a Natural Ankle Trajectory

[+] Author and Article Information
Brandon Y. Tsuge

Mechanical and Aerospace Engineering,
University of California,
Irvine, CA 92697
e-mail: btsuge@uci.edu

Mark M. Plecnik

Electrical Engineering and Computer Science,
University of California,
Berkeley, CA 94720
e-mail: mplecnik@berkeley.edu

J. Michael McCarthy

Fellow ASME
Robotics and Automation Laboratory,
Department of Mechanical and
Aerospace Engineering,
University of California,
Irvine, CA 92697
e-mail: jmmccart@uci.edu

Manuscript received August 15, 2015; final manuscript received July 3, 2016; published online September 8, 2016. Assoc. Editor: Qiaode Jeffrey Ge.

J. Mechanisms Robotics 8(6), 061009 (Sep 08, 2016) (7 pages) Paper No: JMR-15-1225; doi: 10.1115/1.4034141 History: Received August 15, 2015; Revised July 03, 2016

This paper presents a synthesis method for the Stephenson III six-bar linkage that combines the direct solution of the synthesis equations with an optimization strategy to achieve increased performance for path generation. The path synthesis equations for a six-bar linkage can reach as many as 15 points on a curve; however, the degree of the polynomial system is 1046. In order to increase the number of accuracy points and decrease the complexity of the synthesis equations, a new formulation is used that combines 11 point synthesis with optimization techniques to obtain a six-bar linkage that minimizes the distance to 60 accuracy points. This homotopy directed optimization technique is demonstrated by obtaining a Stephenson III six-bar linkage that achieves a specified gait trajectory.

Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Fig. 1

The ankle trajectories achieved by the ARTHuR Step Robot, Ref. [1]

Grahic Jump Location
Fig. 2

Coordinates of the ankle during multiple gait cycles

Grahic Jump Location
Fig. 3

Stephenson III six-bar linkage

Grahic Jump Location
Fig. 4

Coordinates of the ankle relative to the hip joint

Grahic Jump Location
Fig. 5

Ankle trajectory of a single gait cycle relative to the hip joint

Grahic Jump Location
Fig. 6

Set of 60 precision points derived from a basis spline

Grahic Jump Location
Fig. 7

Plot of the 11 starting precision points for the exact six-bar synthesis problem

Grahic Jump Location
Fig. 8

One of 2003 linkage designs in the initial population positioned at the first precision point

Grahic Jump Location
Fig. 11

Solidworks model of the optimized linkage solution

Grahic Jump Location
Fig. 10

One of six optimized linkage solutions in a position with a slightly hyperextended knee joint

Grahic Jump Location
Fig. 9

Optimized Stephenson III linkage solutions that have the largest variance from each other




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In