Article

This study aimed to identify the control strategy of obstacle-crossing of
different heights with a multi-objective optimal control technique. Twelve young
healthy adults walked and crossed obstacles of three different heights while
their kinematic and ground reaction force data were measured simultaneously.
Obstacle-crossing was formulated as an optimal control problem with two
conflicting objectives: minimization of mechanical energy expenditure and
maximization of foot-obstacle clearance. The results supported the hypothesis
that experimentally measured ankle trajectories and joint angles of the swing
limb and the joint moments of the stance limb could be predicted by the best
compromise between these objectives, which was also independent of obstacle
height. This control strategy was fundamentally different from that for
unobstructed gait, and appeared to be pre-programmed into the nervous system. The
results will serve as baseline data and the current technique be used for
identifying changes in obstacle-crossing control strategies in people at higher
risk of falling.
CI - Copyright (c) 2012 Elsevier B.V. All rights reserved.

Langue : ANGLAIS