Jin Shikai, Liu Bin, Wang Zhuo
School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
Biomimetics (Basel). 2025 Jul 1;10(7):424. doi: 10.3390/biomimetics10070424.
This paper presents a novel design for a bionic knee exoskeleton equipped with a variable stiffness actuator based on rope-driven artificial muscles. To meet the varying stiffness requirements of the knee joint across different gait modes, the actuator dynamically switches between multiple rope bundle configurations, thereby enabling effective stiffness modulation. A mathematical model of the knee exoskeleton is developed, and the mechanical properties of the selected flexible aramid fiber ropes under tensile loading are analyzed through both theoretical and experimental approaches. Furthermore, a control framework for the exoskeleton system is proposed. Wearable experiments are conducted to evaluate the effectiveness of the variable stiffness actuation in improving compliance and comfort across various gait patterns. Electromyography (EMG) results further demonstrate that the exoskeleton provides a compensatory effect on the rectus femoris muscle.
本文提出了一种基于绳索驱动人工肌肉的新型可变刚度致动器的仿生膝关节外骨骼设计。为了满足膝关节在不同步态模式下对刚度变化的需求，该致动器在多种绳索束配置之间动态切换，从而实现有效的刚度调制。建立了膝关节外骨骼的数学模型，并通过理论和实验方法分析了所选柔性芳纶纤维绳索在拉伸载荷下的力学性能。此外，还提出了外骨骼系统的控制框架。进行了可穿戴实验，以评估可变刚度致动在改善各种步态模式下的顺应性和舒适性方面的有效性。肌电图（EMG）结果进一步表明，外骨骼对股直肌具有补偿作用。
