Figure 2

Paretic limb data (three steps) from a representative subject with and without the powered exoskeleton. During the powered walking (POWx3), the exoskeleton control signal was generated with magnitude proportional to the paretic soleus EMG (blue) only when the anterior-posterior GRF (black) was greater than 0 (region highlighted in red). Positive GRF denotes anterior (i.e., propulsive) force. During this phase, the exoskeleton supplied plantarflexion moment during late stance (red), contributing to the increased total ankle moment (gray) relative to the NoEXO condition. We note that there is a delay between the onset of the control signal and the onset of the exoskeleton moment (lag of approximately 83 ms).