Human Gait

Modeling, simulation, analysis and synthesis of human gait on inclined slopes

This work is done with Emmanuel Cordier from INRIA, Grenoble, France.

Slope-walking is an important topic and is currently actively studied within the biomechanics community. Inclined surfaces are frequently encountered in everyday life but their effect on the gait is under-studied. Descending slopes, in particular, are often responsible for fall-related accidents in the elderly and thus deserve attention. Gravity is known to have a profound effect on the mechanism of locomotion and our study is aimed at understanding the manner in which the ground slope modifies the influence of gravity on the human body.

Our other motivation behind this research program stems from our challenge of formulating a control law to enable the biped robot to walk on different inclinations. A control law generated for a single slope does not necessarily remain valid for other slopes. Under the assumption that a biological system is efficient or optimal in some sense, we intend to identify ``biologically'' motivated optimality criteria or, at least, to mimic human locomotion with the hope that the robot will be endowed with the same optimal motion. It is possible that the entire dynamics of a complicated system can be generated from a small set of influencing parameters by means of a powerful underlying principle (see above for an example of this in the compass-gait robot). Identification of such a principle will vastly simplify the control strategy.

Based on our experimental data obtained for each 1degree interval within the range of -13degree to +13degree (+/-23.1%) on a variable-inclination treadmill, we have introduced a new technique for the parameterization of slope-walking gaits. By parameterization we mean a quantitative expression of certain gait descriptors as the function of an external parameter, such as the ground slope. The technique is based on cyclograms, the closed curve obtained by simultaneously plotting two (or more) leg joint angles during a typical gait cycle. We demonstrate that the geometric moments of the cyclogram contours can meaningfully reflect the evolution of the gait kinematics on different slopes. We provide a new interpretation of the cyclogram perimeter and discover two potential invariants of the slope-walking gait.

A list of my papers on this topic:

A new gait parameterization technique by means of cyclogram moments: Application to human slope walking
A. Goswami
Gait & Posture, August, 1998.
Download figures of the above paper.

Download slope walk data used for the figures.

Download all the matlab codes used for cyclogram paremeterization.

Download all the moment data derived from the cyclograms.

Download all the matlab codes and data used for automatic cyclogram segmentation.
On this last topic also see:
Segmentation of biomechanical signals by joint-space distance criterion
A. Goswami
17th Congress of the International Society of Biomechanics (ISB), Calgary, Canada, August 1999

Compass-like biped robot Part I: Stability and bifurcation of passive gaits
A. Goswami, B. Thuilot, and B. Espiau
INRIA Research Report No. 2996, October 1996.
Moment-based parameterization of cyclograms of slope-walking
A. Goswami and E. Cordier
XVIth Congress of the Int. Society of Biomechanics, Tokyo, Japan, August 1997 (finalist for the Best Young Investigator award).
Kinematic parameterization of natural slope walking
E. Cordier, A. Goswami, and M. Bourlier
13th Int. Symp. on ``Posture and Gait'', Paris, France, June 1997.
Moment-based parameterization of evolving cyclograms on gradually changing slopes
A. Goswami and E. Cordier
3rd Int. Symp. on Computer Methods in Biomechanics & Biomedical Engr, Barcelona, May, 1997.
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