Simulating the effect of ankle plantarflexion and inversion-eversion exoskeleton torques on center of mass kinematics during walking.
Simulating the effect of ankle plantarflexion and inversion-eversion exoskeleton torques on center of mass kinematics during walking.
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DOI：
10.1371/journal.pcbi.1010712
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发表时间：
2023-08
影响因子：
4.3
通讯作者：
中科院分区：
文献类型：
--
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行走平衡对于独立活动至关重要，而因失去平衡而跌倒是 65 岁及以上人群死亡的主要原因。双足步态通常不稳定，但健康的人类使用校正扭矩来抵消扰动并稳定步态。外骨骼辅助可以通过在下肢关节处提供稳定扭矩来替代失去的肌肉力量和感觉运动控制，从而使患有神经肌肉缺陷的人受益。然而，目前尚不清楚施加的外骨骼扭矩如何转化为步行运动学的变化。这项研究使用肌肉骨骼模拟来研究施加到踝关节和距下关节的外骨骼扭矩如何改变步行过程中的质心运动学。我们首先使用 OpenSim Moco 通过跟踪五个健康成年人记录的实验运动学和地面反作用力来创建肌肉驱动的步行模拟。然后，我们使用前向积分来模拟施加到踝关节和距下关节的外骨骼扭矩的效果，同时根据我们之前的跟踪模拟结果保持肌肉兴奋固定。外骨骼扭矩持续了步态周期的 15%，并且在站立阶段施加在足平放和脚趾离地之间，并且在扭矩施加结束时记录质心运动学的变化。我们发现质心运动学的变化取决于外骨骼扭矩的类型和时间。跖屈扭矩在中间姿势时产生向上和向后的质心速度变化，在接近脚趾离地时产生向上和较小的向前速度变化。外翻和内翻扭矩主要分别产生中间站立时速度的横向和内侧变化。内在的肌肉特性减少了外骨骼扭矩的运动学变化。我们的结果提供了踝关节跖屈和内翻-外翻扭矩以及质心运动学变化之间的映射，这可以为设计人员构建旨在稳定行走过程中平衡的外骨骼提供信息。我们的模拟和软件免费提供，使研究人员能够探索施加的扭矩对平衡和步态的影响。行走平衡对于独立活动至关重要，而因失去平衡而跌倒是 65 岁及以上人群死亡的主要原因。可穿戴机器人设备或外骨骼可以通过为下肢关节提供稳定扭矩来帮助肌肉力量和运动控制能力较差的人避免跌倒。然而，目前尚不清楚外骨骼扭矩如何改变步行运动。在这项研究中，我们使用计算机模拟来研究施加到脚踝的外骨骼扭矩如何改变身体质心的运动。我们首先使用生物力学精确的模型创建了真实的步行模拟。然后，我们模拟了外骨骼扭矩应用于跖屈（即伸展）、内翻或外翻脚踝的模型的效果。我们发现跖屈扭矩使质心向后或向前移动，具体取决于步行周期中施加扭矩的时间。跖屈扭矩也使质心向上移动。外翻和反转扭矩产生质心的左右运动。最后，我们发现模型中肌肉的产力特性减少了外骨骼扭矩的质心变化。我们的研究结果可以帮助外骨骼设计师创建稳定行走平衡的设备。
Walking balance is central to independent mobility, and falls due to loss of balance are a leading cause of death for people 65 years of age and older. Bipedal gait is typically unstable, but healthy humans use corrective torques to counteract perturbations and stabilize gait. Exoskeleton assistance could benefit people with neuromuscular deficits by providing stabilizing torques at lower-limb joints to replace lost muscle strength and sensorimotor control. However, it is unclear how applied exoskeleton torques translate to changes in walking kinematics. This study used musculoskeletal simulation to investigate how exoskeleton torques applied to the ankle and subtalar joints alter center of mass kinematics during walking. We first created muscle-driven walking simulations using OpenSim Moco by tracking experimental kinematics and ground reaction forces recorded from five healthy adults. We then used forward integration to simulate the effect of exoskeleton torques applied to the ankle and subtalar joints while keeping muscle excitations fixed based on our previous tracking simulation results. Exoskeleton torque lasted for 15% of the gait cycle and was applied between foot-flat and toe-off during the stance phase, and changes in center of mass kinematics were recorded when the torque application ended. We found that changes in center of mass kinematics were dependent on both the type and timing of exoskeleton torques. Plantarflexion torques produced upward and backward changes in velocity of the center of mass in mid-stance and upward and smaller forward velocity changes near toe-off. Eversion and inversion torques primarily produced lateral and medial changes in velocity in mid-stance, respectively. Intrinsic muscle properties reduced kinematic changes from exoskeleton torques. Our results provide mappings between ankle plantarflexion and inversion-eversion torques and changes in center of mass kinematics which can inform designers building exoskeletons aimed at stabilizing balance during walking. Our simulations and software are freely available and allow researchers to explore the effects of applied torques on balance and gait. Walking balance is central to independent mobility, and falls due to loss of balance are a leading cause of death for people 65 years of age and older. Wearable robotic devices, or exoskeletons, could help people with reduced muscle strength and motor control avoid falls by providing stabilizing torques at lower-limb joints. However, it is currently unclear how exoskeleton torques change walking motions. In this study, we used computer simulation to investigate how exoskeleton torques applied to the ankle change the motion of the body’s center of mass. We first created realistic simulations of walking using a biomechanically accurate model. We then simulated the effect of exoskeleton torques applied to the model that plantarflexed (i.e., extended), inverted, or everted the ankle. We found that plantarflexion torques moved the center of mass backwards or forwards, depending on when the torque was applied during the walking cycle. Plantarflexion torques also moved the center of mass upwards. Eversion and inversion torques produced left-right motions of the center of mass. Finally, we found that the force-generating properties of muscles in our model reduced the center of mass changes from exoskeleton torques. Our results can help exoskeleton designers create devices that stabilize walking balance.
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影响因子：
2.4
作者：
DeMers MS;Hicks JL;Delp SL
通讯作者：
Delp SL
影响因子：
3.7
作者：
Falisse A;Afschrift M;De Groote F
通讯作者：
De Groote F
影响因子：
4.6
作者：
Afschrift M;Pitto L;Aerts W;van Deursen R;Jonkers I;De Groote F
通讯作者：
De Groote F
影响因子：
5.1
作者：
Bayón C;Keemink AQL;van Mierlo M;Rampeltshammer W;van der Kooij H;van Asseldonk EHF
通讯作者：
van Asseldonk EHF
影响因子：
25
作者：
Beck, Owen N.;Shepherd, Max K.;Rastogi, Rish;Martino, Giovanni;Ting, Lena H.;Sawicki, Gregory S.
通讯作者：
Sawicki, Gregory S.