Sensor-guided Gait Synchronization for Weight-Support Lower-Extremity-Exoskeleton

This paper presents the design of a sensor-guided gait-synchronization mechanism for a weight-support lower-extremity-exoskeleton (LEE), which provides motion to a (osteoarthritis or stroke rehab) passive leg in sync with the healthy (active) leg in the swing phase during walking. The gait synchronization system is integrated with a motorized hip-joint with embedded sensors that measure the angular displacements and velocities of both hip joints, and the inertia properties of the knee joint. Based on the measured joint-angle trajectories, the motorized hip-joint lifts the passive leg in sync with the healthy leg during the swing phase. The sensor-guided gait mechanism and its effectiveness of synchronizing the passive hip with the active leg are experimentally illustrated. Based on joint-angle and plantar-force measurements, the effects of the passive LEE and sensor-guided gait-synchronization on human walking were experimentally investigated. Results comparing with/without the passive LEE and with/without gait synchronization validate the effectiveness of the sensor-guided designs for reducing joint-angle errors due to the weight of the LEE.