背景:从人体运动中获取的生物力学能量为便携式电子设备以及计算机化和机动化假肢提供了一种有前途的清洁替代电源。我们提出了从人体获取能量的理论,并描述了可以从人体热量和步行过程中身体各个部位的运动中获取的能量,如脚跟撞击;脚踝,膝盖,臀部,肩膀,和肘关节运动;和质心垂直运动。
方法:我们评估了行走过程中的主要运动,并确定了身体消耗的工作量和可恢复能量的部分。在行走过程中,关节的运动阶段有肌肉作为刹车,能量损失到周围环境。在这些运动阶段,所需的制动力或扭矩可以由发电机代替,允许以最小的额外努力为代价收获能量。通过实验和文献数据估算了可以收获的能量。根据我们的结果,结合对最先进的生物力学能量收集设备和能量转换方法的回顾,提出了未来方向的建议。
结果:对于使用质心运动的设备,可以收获的能量的最大量大约是每千克设备重量的1W。对于体重80公斤且以大约4公里/小时的速度行走的人,脚跟撞击产生的功率约为2W。对于基于再生制动的关节安装装置,产生最大力量的关节是膝盖(34W)和脚踝(20W)。
结论:我们的理论计算与当前器件性能数据吻合良好。我们的结果表明,可以从下肢关节获得最多的能量,但是为了有效地做到这一点,一个创新和重量轻的机械设计是必要的。我们还将携带电池的选择与收集能量的代谢成本进行了比较,并研究了将机械能转换为电能的方法的优点。
BACKGROUND: Biomechanical energy harvesting from human motion presents a promising clean alternative to electrical power supplied by batteries for portable electronic devices and for computerized and motorized prosthetics. We present the theory of energy harvesting from the human body and describe the amount of energy that can be harvested from body heat and from motions of various parts of the body during walking, such as heel strike; ankle, knee, hip, shoulder, and elbow joint motion; and center of mass vertical motion.
METHODS: We evaluated major motions performed during walking and identified the amount of work the body expends and the portion of recoverable energy. During walking, there are phases of the motion at the joints where muscles act as brakes and energy is lost to the surroundings. During those phases of motion, the required braking force or torque can be replaced by an electrical generator, allowing energy to be harvested at the cost of only minimal additional effort. The amount of energy that can be harvested was estimated experimentally and from literature data. Recommendations for future directions are made on the basis of our results in combination with a review of state-of-the-art biomechanical energy harvesting devices and energy conversion methods.
RESULTS: For a device that uses center of mass motion, the maximum amount of energy that can be harvested is approximately 1 W per kilogram of device weight. For a person weighing 80 kg and walking at approximately 4 km/h, the power generation from the heel strike is approximately 2 W. For a joint-mounted device based on generative braking, the joints generating the most power are the knees (34 W) and the ankles (20 W).
CONCLUSIONS: Our theoretical calculations align well with current device performance data. Our results suggest that the most energy can be harvested from the lower limb joints, but to do so efficiently, an innovative and light-weight mechanical design is needed. We also compared the option of carrying batteries to the metabolic cost of harvesting the energy, and examined the advantages of methods for conversion of mechanical energy into electrical energy.