Study On Principles And Key Technologies Of Human Kinetic Energy Harvesting

The prevalence of wearable electronics gives rise to the problem of sustainable power supply. Plenty of methods, including scavenging heat, light, vibration, have been proposed to address this problem with only limited promise. Other than the methods mentioned above, harvesting energy from human motion, which maintains a relatively stable and powerful energy supply for wearable electronics, seems more persuasive.Here, we developed several wearable energy harvesters based on the motion patterns of human body’s foot strike, trunk and knee joint in order to provide a sustainable power supply for portable electronics. Prior to the design of harvesters, the motion patterns of foot strike, trunk and knee joint are clarified and mathematical models of human motion are built. Inspired by the motion patterns, we propose two kinds of in-shoe energy harvesters, three backpack harvesters and a wearable knee joint harvester to capture the motion of foot strike, trunk and knee joint, respectively. To improve the output power, some mechanisms, such as amplifier, gears trains, are applied to the design of harvesters. The coupling between harvesters and human body also serves as a critical design consideration. In addition, for the convenience of powering the electronics, circuits are also designed to match the harvesters.Based on the mathematical models of human motion, dynamic models of the harvester are provided to predict their performances. The theoretical output power and efficiency of the harvesters can be drawn from dynamic models. Furthermore, we build prototypes of the harvesters for experimental validation. The experimental results show that a maximum output power of 1W for in-shoe harvesters, 7W for backpack harvesters and 5.8W for knee joint harvesters is achieved, which can practically provide a sustainable power supply for wearable electronics.