A fiber grating human-robot interaction force sensor for lower limb rehabilitation exoskeleton

Knee osteoarthritis remains challenging to cure fundamentally, necessitating strategies to delay disease progression and enhance knee joint function through rehabilitation. Integrating sensors into lower limb rehabilitation exoskeletons can impart sensory capabilities, allowing for the collection and feedback of patient data during rehabilitation. This facilitates motor intention perception and quantitative rehabilitation evaluation. The human-robot interaction force is a reliable signal that provides patient motion state information using minimal sensors without significant performance variation. This study introduces a fiber grating human-robot interaction force sensor for lower limb rehabilitation exoskeleton, designed for easy installation due to its compact size. The sensor measures interaction force on the human sagittal plane, with three fiber gratings positioned at 120° intervals around the sensor’s circumference and an additional grating for temperature compensation. Experimental results indicate the sensor’s axial force detection range is 0 to 100 N, with a resolution of 0.1 N.