Adaptive multi-objective control explains how humans make lateral maneuvers while walking
Fig 2
Experimental Stepping Time Series and Errors.
A) Time series of left (zL; blue) and right (zR; red) foot placements for (i) 38 transitions when the cue was given on a contralateral step relative to the direction of transition, (ii) 41 transitions when the cue was given on an ipsilateral step relative to the direction of transition, and (iii) all 79 transitions with respect to the initiation of the transition, defined as the last step taken on the original path. In (i)-(ii), the black dotted lines at step 0 indicate the onset of the audible cue. All transitions are plotted to appear from left to right. B) Time series of lateral position (zB) and step width (w) for all transitions with respect to the initiation of the transition, with all transitions plotted to appear from left to right. C) Errors with respect to the stepping goals, [zB*, w*]. For steps in the interval [–3, 0], zB* was defined as the experimental mean zB during steady state walking before the transition. For steps in the interval [1,7], zB* was defined as the experimental mean zB during steady state walking after the transition. For all steps analyzed, w* was defined as the experimental mean w during steady state walking. Error bars indicate experimental standard deviations at each step. Gray shaded regions indicate the mean ±1 standard deviation from all steady state walking steps.