Physical interface dynamics alter how robotic exosuits augment human movement: implications for optimizing wearable assistive devices.
Physical interface dynamics alter how robotic exosuits augment human movement: implications for optimizing wearable assistive devices.
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DOI：
10.1186/s12984-017-0247-9
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发表时间：
2017-05-18
影响因子：
5.1
通讯作者：
Zelik KE
中科院分区：
文献类型：
--
作者：
Yandell MB;Quinlivan BT;Popov D;Walsh C;Zelik KE
可穿戴辅助设备已经证明有潜力改善残疾人的行动能力，并增强健康的人类表现；然而，这些好处取决于电力从设备传输到人类用户的有效程度。由于生物组织和物理界面材料在负载下变形和位移、吸收和返回能量时发生的复杂的人-设备界面动力学，因此量化和理解这种能量传递是具有挑战性的。在这里，我们介绍了一种新的方法来快速估计运动任务中的界面功率动态，使用常见的运动捕捉和力测量，然后应用该方法来量化软机器人踝关节外衣在行走过程中如何与人体交互并将能量传递给人体。我们将外衣末端效应器的功率(即从装置输出的功率)划分为增加踝关节屈膝的功率(称为增强功率)和用于界面材料和底层软组织的变形和运动的功率(称为界面功率)。我们提供了人体-外衣界面如何吸收和返回能量的经验证据，重塑了外衣到人体的能量流，并导致了三个关键后果：(1)在外衣加载过程中(随着外力的增加)，约55%的外衣末端效应器能量被吸收到界面中。然而，在随后的外衣卸载期间(随着外加力的减少)，大部分被吸收的界面功率以粘弹性方式返回。因此，大多数(约75%)的外衣末端效应器在每一步中的工作有助于增加脚踝的足底屈曲。(3)由于这些界面能量吸收和返回动力学，踝关节增强力(和功)相对于外衣末端效应器的功率延迟。我们的发现阐明了从辅助设备到人体的能量传输过程中人-外衣界面动力学的复杂性，并为改进可穿戴机器人的设计和控制提供了见解。我们的结论是，为了优化可穿戴辅助设备的性能，在整个设计和评估阶段，重要的是考虑影响功率传输的人-设备界面动态，从而提高人类的增强效益。本文的在线版本(doi：10.1186/s12984-0170247-9)包含补充材料，授权用户可以使用。
Wearable assistive devices have demonstrated the potential to improve mobility outcomes for individuals with disabilities, and to augment healthy human performance; however, these benefits depend on how effectively power is transmitted from the device to the human user. Quantifying and understanding this power transmission is challenging due to complex human-device interface dynamics that occur as biological tissues and physical interface materials deform and displace under load, absorbing and returning power. Here we introduce a new methodology for quickly estimating interface power dynamics during movement tasks using common motion capture and force measurements, and then apply this method to quantify how a soft robotic ankle exosuit interacts with and transfers power to the human body during walking. We partition exosuit end-effector power (i.e., power output from the device) into power that augments ankle plantarflexion (termed augmentation power) vs. power that goes into deformation and motion of interface materials and underlying soft tissues (termed interface power). We provide empirical evidence of how human-exosuit interfaces absorb and return energy, reshaping exosuit-to-human power flow and resulting in three key consequences: (i) During exosuit loading (as applied forces increased), about 55% of exosuit end-effector power was absorbed into the interfaces. (ii) However, during subsequent exosuit unloading (as applied forces decreased) most of the absorbed interface power was returned viscoelastically. Consequently, the majority (about 75%) of exosuit end-effector work over each stride contributed to augmenting ankle plantarflexion. (iii) Ankle augmentation power (and work) was delayed relative to exosuit end-effector power, due to these interface energy absorption and return dynamics. Our findings elucidate the complexities of human-exosuit interface dynamics during transmission of power from assistive devices to the human body, and provide insight into improving the design and control of wearable robots. We conclude that in order to optimize the performance of wearable assistive devices it is important, throughout design and evaluation phases, to account for human-device interface dynamics that affect power transmission and thus human augmentation benefits. The online version of this article (doi:10.1186/s12984-017-0247-9) contains supplementary material, which is available to authorized users.