Generating electricity while walking with a carried mass oscillating in the medial-lateral direction

We developed a novel load carriage system that allows weight carried in a backpack to oscillate in the medial-lateral direction while simultaneously generating electricity from the carried weight’s oscillations. We use the energy harvesting capabilities of the device to control carried mass oscillation amplitude and phase relative to centre of mass movement. We tested seven different energy harvesting conditions and compared them to walking with the device when the carried weight is rigidly fixed to the backpack frame. The device generated up to 0.22±0.03 W of electricity, at no additional metabolic cost to the user, when compared to walking with the carried weight rigidly fixed. Although there were no significant changes in the work performed by lower limb joints between conditions, the oscillating mass significantly reduced the forces experienced by the user in the medial-lateral direction, compared to walking with a fixed mass.