Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Australia.
School of Engineering, Monash University, Selangor, Malaysia.
Med Biol Eng Comput. 2023 May;61(5):1167-1182. doi: 10.1007/s11517-023-02778-2. Epub 2023 Jan 23.
This simulation study aimed to explore the effects of mass and mass distribution of powered ankle-foot orthoses, on net joint moments and individual muscle forces throughout the lower limb. Using OpenSim inverse kinematics, dynamics, and static optimization tools, the gait cycles of ten subjects were analyzed. The biomechanical models of these subjects were appended with ideal powered ankle-foot orthoses of different masses and actuator positions, as to determine the effect that these design factors had on the subject's kinetics during normal walking. It was found that when the mass of the device was distributed more distally and posteriorly on the leg, both the net joint moments and overall lower limb muscle forces were more negatively impacted. However, individual muscle forces were found to have varying results which were attributed to the flow-on effect of the orthosis, the antagonistic pairing of muscles, and how the activity of individual muscles affect each other. It was found that mass and mass distribution of powered ankle-foot orthoses could be optimized as to more accurately mimic natural kinetics, reducing net joint moments and overall muscle forces of the lower limb, and must consider individual muscles as to reduce potentially detrimental muscle fatigue or muscular disuse. OpenSim modelling method to explore the effect of mass and mass distribution on muscle forces and joint moments, showing potential mass positioning and the effects of these positions, mass, and actuation on the muscle force integral.
本仿真研究旨在探讨动力踝足矫形器的质量和质量分布对下肢净关节力矩和各肌肉力的影响。采用 OpenSim 运动学逆动力学、动力学和静态优化工具，分析了 10 名受试者的步态周期。为了确定这些设计因素对受试者正常行走时动力学的影响，在这些受试者的生物力学模型上附加了不同质量和执行器位置的理想动力踝足矫形器。结果发现，当装置的质量分布在腿部更靠远端和更靠后时，净关节力矩和整个下肢肌肉力的负面影响更大。然而，发现各肌肉力的结果不同，这归因于矫形器的连锁效应、肌肉的拮抗配对以及各肌肉的活动如何相互影响。结果表明，动力踝足矫形器的质量和质量分布可以进行优化，以更准确地模拟自然动力学，降低下肢的净关节力矩和整体肌肉力，并且必须考虑各肌肉，以减少潜在的有害肌肉疲劳或肌肉失用。OpenSim 建模方法探讨了质量和质量分布对肌肉力和关节力矩的影响，展示了潜在的质量定位以及这些位置、质量和致动对肌肉力积分的影响。
