Macro fiber composite-based energy harvester for human knee

The harvesting of energy from human motion for portable and wearable electronic devices has received considerable attention. This letter describes a lightweight macrofiber composite (MFC)-based energy harvester for capturing biomechanical energy through the natural motion of the human knee. In the proposed device, a slider-crank mechanism is used to transform the rotary motion of the knee joint to linear motion, and a bending beam is used to transform the linear motion to a bending motion. When walking, a bending deformation is induced in two MFC slices attached to the bending beam, generating electrical energy. To test the performance of the developed device, treadmill tests at various walking speeds and resistive loads are performed. Experimental results show that the lightweight harvester (weighing just 307 g) can generate 1.60 mW without increasing the human effort required for walking. This is expected to significantly promote the usage of biomechanical energy harvesters.