Novel gait adaptation and neuromotor training results using an active leg exoskeleton

The gait of every adult is unique and expected to be ingrained within the neuromuscular system. The major scientific question that we ask in this paper if it is possible to alter the gait of healthy individuals using special purpose design of robots and training paradigms. This paper describes novel experimental results with an active leg exoskeleton (ALEX) and a force-field controller (FFC) developed for neuromotor training of gait and rehabilitation of patients with walking disabilities. ALEX is a motorized leg orthosis having a total of 7 DOFs with hip and knee actuated in the sagittal plane. The FFC applies forces on the foot to help the leg move on a desired trajectory. The interaction forces between the subject and the orthosis are designed to be "assist-as- needed" for safe and effective gait training. Simulations and experimental results with the FFC are presented. Experiments have been performed on six healthy subjects walking on a treadmill. It was shown that a healthy subject could be retrained in about 45 min with ALEX to walk on a treadmill with a considerably altered gait. In the coming months, this powered orthosis will be used for gait training of stroke patients.