Monitoring upper limbs during exoskeleton-assisted gait outdoors

Powered exoskeleton can restore locomotion to spinal cord injury subjects but measuring their impact on the upper limbs is critical, since repeated excessive loads are strongly correlated to chronic pain at shoulder level. This paper presents a novel set of instrumented crutches, able to measure force exerted on the ground during walking sessions, thanks to embedded time-of-flight cameras and force sensors. The force sensors, along with an inertial module, assess the force acting on the upper limbs, while the time-of-flight cameras detects the gait phases looking at the feet position. The aim is to provide an affordable measuring system, without requiring a fully instrumented gait-lab, allowing the user-robot interaction to be measured in a more natural setting, closer to the foreseen working condition. The instrumented crutches are fully independent of any other instrumentation to allow a comparison of different exoskeleton models in terms of upper limb involvement.