Figure 6.

Orthosis ankle joint kinetics. Data traces are mean (solid lines) + 1 SD (thin lines) from the left leg of three subjects who walked overground at 1.25 m/s with a knee-ankle-foot orthosis powered in two control modes. In the left column, data from powered trials with direct proportional myoelectric control (PM, red) for net torque (N-m/kg) (top) generated by the ankle joint artificial muscles and the resulting mechanical power (W/kg) (bottom) is compared with the net ankle muscle-tendon moment (N-m/kg) and mechanical power (W/kg) recorded during walking without the orthosis (black). The right column shows similar data for powered trials using proportional myoelectric control with a flexor inhibition algorithm (PMFI, blue). Stride cycles begin (0%) and end (100%) at left heel strike. Dotted vertical lines mark the stance-swing transition at ~60% of the stride cycle. Plantar flexor torque/moment is positive. Positive mechanical power indicates energy generation and negative mechanical power indicates energy absorption.