A fully mechanical method and experiment to harvest multiple arm joint energy

Currently, energy harvesting devices for arms suffer from lower power caused by the single joint harvesting. To overcome the above problem, a multiple arm joints energy harvesting strategy is presented in this paper. On the basis of this strategy, the simultaneous arm harvester (SAH) adopts a fully mechanical method to harvest multiple arm joints energy. The SAH uses a differential bevel gear train structure to achieve forearm and upper-arm simultaneous harvesting. The experimental results show that the SAH can achieve a maximum voltage of 22.0 V and a power of 290.1 mW. Compared to the single joint harvesting, the SAH under the forearm and upper-arm simultaneous downward swing increases the open-circuit voltage by 111.5% and the output power by 351.9%. Additionally, SAH can generate a maximum power density of 280.5 mW/kg. Experiments verify that the SAH can improve the energy harvesting efficiency of the arm through multiple arm joint harvesting. The SAH has greater potential for portable electronic equipment applications in field activities.