Exoskeleton Control for Post-stoke Gait Training of a Paretic Limb Based on Extraction of the Contralateral Gait Phase
We developed a lightweight lower-limb exoskeleton to assist the paretic leg of stroke patients during gait training. The device features compliant actuators separated from the patient’s limb, thus avoiding any gait disruption caused by the actuators’ inertia. The exoskeleton control uses motion data from the healthy leg to extract a reference gait phase. In this context, phase is a continuous variable that tracks the progress of the gait over one cycle and wraps around at the end of the cycle. The extracted phase information is used to time the assistive torque acting on the impaired leg. Control of the assistive torque is implemented as a force control acting on a time-varying linear system representing the actuator and exoskeleton. Results from one experiment show how the exoskeleton helps improve knee flexion during the swing phase of the gait cycle.