Proof-of-concept of a Robotic Knee Exoskeleton in Healthy Subjects and Hemiparetic Patients During Gait.

Subjects were instructed to walk on a treadmill at a constant speed during trials of 5 minutes. All subjects carried out four trials: (1) NoExo: subjects only wore the sensors to acquire their basal motion; (2) Free: subjects wore the exoskeleton although the actuator was mechanically decoupled, so it enabled the free movement of the knee; (3) Echo: the device provided gait assistance following the Echo-control strategy; and (4) Pattern: the device provided gait assistance following the Pattern strategy. During trials, patients wore a safety harness that did not support any weight. Previously to the execution of the trials, the gait velocity was self-selected by the subjects to a comfortable level. Subjects rested between trials for five minutes. Healthy subjects also performed a previous trial under variable gait speed. They walked over the treadmill as in the NoExo condition, although the gait speed randomly varies from 1km/h to 3km/h in 0.2km/h steps for 15 seconds at least.