Synergetic Integration of Energy Recovery across Multiple Joint in Human Lower Limb Motion: A Biomechanical Exploration

Current energy harvesting devices in the field of human lower limb energy recovery have the problems of low energy recovery efficiency and large mass and volume. To solve these problems, this article proposes a multijoint synergistic energy recovery device based on the concept of synergistic energy recovery, with the aim of allowing one energy harvester to collect negative work from multiple joints simultaneously. The recovery efficiency of the harvester is improved by increasing the energy recovery source. The mechanism achieves synergistic recovery of negative work in multiple joints of the human lower limb. The mechanical structure consists of a four-bar mechanism, limit switches, a planetary gear system, and a differential mechanism to complete the energy capture and coupling. Multiple energy streams are superimposed in an orderly manner without loss. The experimental results demonstrate the efficient output of this harvester in collecting and coupling energy in the negative work zone of the knee and hip joints. This integrated multijoint energy harvester achieves an output voltage of 118 V under normal human walking conditions. The device achieves a power output of 3.21 W and a power density of 7.32 W kg⁻¹ at 2 Hz.