Modeling of control and learning in a stepping motion

H. Flashner, A. Beuter, Ara - Arabyan

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

In a previous study (Beuter et al. 1986) the authors modeled a stepping motion using a three-body linkage with four degrees of freedom. Stepping was simulated by using three task parameters (i.e., step height, length, and duration) and sinusoidal joint angular velocity profiles. The results supported the concept of a hierarchical control structure with open-loop control during normal operation. In this study we refine the dynamic model and improve the simulation technique by incorporating the dynamics of the leg after landing, adding a foot segment to the model, and preprogramming the complete step motion using cycloids. The equations of the forces and torques developed on the ground by the foot during the landing phase are derived using the Lagrangian method. Simulation results are compared to experimental data collected on a subject stepping four times over an obstacle using a Selspot motion analysis system. A hierarchical control model that incorporates a learning process is proposed. The model allows an efficient combination of open and closed loop control strategies and involves hardwired movement segments. We also test the hypothesis of cycloidal velocity profiles in the joint programs against experimental data using a novel curve-fitting procedure based on analytical rather than numerical differentiation. The results suggest multiob-jective optimization of the joint's motion. The control and learning model proposed here will help the understanding of the mechanisms responsible for assembling selected movement segments into goaldirected movement sequences in humans.

Original languageEnglish (US)
Pages (from-to)387-396
Number of pages10
JournalBiological Cybernetics
Volume55
Issue number6
DOIs
StatePublished - Mar 1987
Externally publishedYes

Fingerprint

Learning
Foot
Landing
Joints
Torque
Curve fitting
Angular velocity
Leg
Dynamic models

ASJC Scopus subject areas

  • Biophysics

Cite this

Modeling of control and learning in a stepping motion. / Flashner, H.; Beuter, A.; Arabyan, Ara -.

In: Biological Cybernetics, Vol. 55, No. 6, 03.1987, p. 387-396.

Research output: Contribution to journalArticle

Flashner, H. ; Beuter, A. ; Arabyan, Ara -. / Modeling of control and learning in a stepping motion. In: Biological Cybernetics. 1987 ; Vol. 55, No. 6. pp. 387-396.
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