A Multi-Joint Energy Harvesting Device for Lower-Limb Gait Support with a Customized Optimization Strategy

Wearable energy harvesting devices have demonstrated great potential in the field of patient care due to their ability to provide continuous power for daily monitoring equipment. However, the energy recovery potential of different lower limb joints varies depending on the degree of pathological conditions in patients. Traditional wearable energy harvesting devices predominantly focus on recovering negative work during knee extension and converting it into electrical energy, which may not be suitable for wearers with knee joint disorders. This paper presents a novel multi-joint energy harvesting device that achieves energy recovery and motion assistance for both the hip and knee joints using a differential gear system, equipped with a single generator and a solitary spiral spring. Additionally, to address the differences in walking habits among individuals, a customized multi-objective optimization energy recovery strategy is proposed. This method adjusts parameters such as the device and cable fixation positions, the pre-tightening angle of the spiral spring, and the external circuit load resistance, aiming to maximize energy recovery efficiency while enabling both motion assistance and joint training. Preliminary power generation experiments indicate that the device achieves a peak power output of 1.78±0.18 W and an average power output of 0.37±0.01 W.