肌力协同补偿的无动力下肢外骨骼设计与分析

Design and analysis of unpowered lower-limb exoskeleton with muscle strength synergistic compensation

无动力外骨骼具有质量小、代谢能耗低、基本不改变正常步态、无需外动力源和可持续工作时间长等优点,已逐渐成为新型外骨骼领域的研究热点。为提升常规无动力下肢外骨骼对步态能量的利用效率,设计了一种肌力协同补偿的无动力下肢外骨骼。首先,通过建立人体下肢动力学模型分析了行走过程中下肢能量的变化规律,得到了步态能量的储存与释放机理;然后,结合设置代起止点的折线路径及肌力贡献度,制定了关节肌肉的肌力协同补偿路径;最后,基于踝、髋关节的刚度设计了弹性储能元件,构建了一款无动力柔性下肢外骨骼,并利用OpenSim软件分析了有无穿戴外骨骼时人体下肢相关肌肉在行走过程中的代谢能耗。结果表明,在穿戴无动力下肢外骨骼时,比目鱼肌、腓肠肌和胫骨前肌的代谢能耗分别降低了31.5%,34.7%和40.0%,股直肌、阔筋膜张肌和缝匠肌的代谢能耗分别降低了36.3%,7.0%和5.0%;单个步态周期内下肢相关肌肉的总代谢能耗降低了15.5%。研究结果可为低代谢能耗的无动力下肢外骨骼的优化设计提供一定的理论依据。

The unpowered exoskeleton has the advantages of small mass, low metabolic energy consumption, basically no change in normal gait, no need for external power source and long sustainable working time, which has gradually become a research hot spot in the field of new exoskeletons. In order to improve the gait energy utilization efficiency of the conventional unpowered lower-limb exoskeleton, a unpowered lower-limb exoskeleton with muscle strength synergistic compensation was designed. Firstly, the energy change law of lower limbs during walking was analyzed by establishing a human lower limb dynamics model, and the mechanism of storage and release of gait energy was obtained;then, combined with the polyline path with substitute start and end point and the muscle strength contribution, the muscle strength synergistic compensation path of the joint muscle was formulated;finally, based on the stiffness of ankle and hip joint, the elastic energy storage elements were designed to construct an unpowered flexible lower-limb exoskeleton, and the OpenSim software was used to analyze the metabolic energy consumption of human lower limb muscles during walking with or without wearing the exoskeleton. The results showed that when wearing the unpowered lowerlimb exoskeleton, the metabolic energy consumption of soleus, gastrocnemius and anterior tibial decreased by 31.5%, 34.7% and 40.0%, respectively, and the metabolic energy consumption of rectus femoris, tensor fascia lata and sartorius decreased by 36.3%, 7.0% and 5.0%, respectively;the total metabolic energy consumption of the related lower limb muscles decreased by 15.5% in a single gait cycle. The research results can provide a theoretical basis for the optimal design of unpowered lowerlimb exoskeleton with low metabolic energy consumption.