Tranforming Lateral Limbs Movement To Vertical Frequency-Up -Conversion (Fuc) Resonance For Wearable Energy Harvesters

This paper reports a novel wearable energy-harvester to generate electric-power from human-joint rotation induced lateral stretch/rebound of the flexible substrate. The energy harvester integrates micro-plated nickel cantilever with the piezoelectric film and fixes them to the flexible substrate. By using the magnetic coupled frequency-up-conversion (FUC) between the ferromagnetic nickel cantilever and the magnet on the substrate, the low frequency lateral human limbs movement is converted into high-frequency vertical (perpendicular to the substrate) resonant power generation of the piezoelectric cantilever, thereby effectively generating stable electric energy. Within the whole elbow/knee movement in the frequency range of 0.5Hz similar to 5.0Hz, the electric -energy generated in one movement cycle always stably keeps within 0.56 mu J similar to 0.69 mu J. Body kinetic energy -harvesting experiments under limbs movements like squat, walking, jogging and fast running have verified the device to be promising in various wearable applications.