Effects of Work Sharing of Upper and Lower Limbs (WULL) During Ambulatory Movements

During this research, the first prototype of the Workshare Upper Lower Limb (WULL) exoskeleton was developed. The goal of this exoskeleton is to create a kinetic couple between the upper and lower body. To achieve the goal, existing orthoses were modified and fitted to each other to create an ergonomic platform to attach all the force transmission elements. The force was transmitted from the upper to the lower limbs by a system of pulleys and Bowden cables. The pulleys were placed on the joints with a Boa ratchet to tension each of the lines. The Bowden cables were routed through the back to avoid any entanglement. To test the efficacy of the device, eight EMG sensors were placed on five participants to track the muscle activation during different exercises. Besides the EMGs multiple IMUs were placed on the participant to also track the motion of the joints. The validation of the device was done over twenty sessions that consisted of 4 exercises. Overall, the device showed that when kinematically connecting the upper and lower body, the lower limbs exert less effort. When looking at low dynamic motions, the device was able to assist the participant by reducing the work of the muscle by about 20%. When the device was used in a high dynamic scenario, the change was not so clear. In the current state, the device requires good coordination between the upper and lower limbs to fully take advantage of the system. With this device and the results shown, a foundation for these kinematic couplers has been set, and many variations of this device can be made