A human locomotion driven hybrid energy harvester for wrist wearable applications
In this work, a human locomotion driven hybrid energy generator has been proposed and experimentally validated for scavenging significant biomechanical energy from natural motion of arm swinging, to be used for wrist-wearable smart device applications. A proposed hybrid electromagnetic (EM) and triboelectric (TE) generator can deliver much higher output power than that of the individual harvesting device unit due to the combinational operation of EM and TE mechanisms under the same applied mechanical movements. A novel curved structural design based energy harvester is proposed from the comparative analysis of human hand swinging motion with double pendulum motion, which helps to enhance the output performance and design it fit to wear on wrist. The swinging of human arm during walking and running initiates a freely movable magnetic metal ball to oscillate inside the curved structure through both EM and TE part. The EM part consists of two coils wrapped around the curved body, one at each end and micro-structured Polydimethylsiloxane (PDMS) film is attached on the inner wall of curved body along with copper electrode for TE part. A prototype of the hybrid harvester has been fabricated and tested. The EM and TE devices are capable of delivering maximum 84.37mW peak power at 49.2Ω matching load resistance and 1.86μW peak power at 10MΩ load resistance respectively which are considerably higher than the trending state-of-the-art devices.