Effect of Hip Assistance Modes on Metabolic Cost of Walking With a Soft Exoskeleton
Effect of Hip Assistance Modes on Metabolic Cost of Walking With a Soft Exoskeleton
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DOI：
10.1109/tase.2020.3027748
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发表时间：
2021-04-01
影响因子：
5.6
通讯作者：
Wu, Xinyu
中科院分区：
文献类型：
--
作者：
Cao, Wujing;Chen, Chunjie;Wu, Xinyu
了解不同髋关节辅助模式的影响是设计髋关节辅助设备和控制器的过程中的基本步骤，这些设备和控制器可以在代谢成本方面提供更好的性能。我们已经开发并测试了用于髋关节辅助的软外骨骼，其包括三种辅助模式：髋关节伸展辅助（HEA）、髋关节屈曲辅助（HFA）以及髋关节伸展和屈曲辅助（HEFA）。提出了一种基于前馈模型的比例微分（PD）迭代学习控制器，实现了对辅助力的精确控制。三个髋关节辅助模式进行了评估，7名男性受试者在跑步机上行走的速度为5公里/小时，在两个banks-first与15公斤的背包，然后没有任何背包。HEA、HFA和HEFA在负载条件下的净代谢成本比无外骨骼条件下分别降低了9.95%、6.25%和15.28%。发现HEA（p = 0.048）和HEFA（p = 0.005）模式的降低具有显著性，而HFA模式（p = 0.202）无统计学显著性。这表明，与HFA模式相比，具有软外骨骼的HEA和HEFA模式提供了更大的净代谢成本效益。HEA、HFA和HEFA在无负荷条件下的净代谢成本分别为9.21%、2.58%和13.05%。在两种情况下，与发达国家的软外骨骼的步行效率的改善进行了演示。注从业者-这篇文章的动机是如何减少代谢成本最适当的问题，通过髋关节软外骨骼的帮助下步行。本文通过对三种髋关节辅助方式的比较，探讨了系统重量和辅助效率的平衡问题。然后，我们提出了一个PD迭代学习控制器的前馈模型的基础上，精确跟踪所需的辅助力。初步实验表明，髋关节伸展辅助（HEA）比髋关节屈曲辅助（HFA）更适合于髋关节辅助在单一的运动辅助。当软外骨骼的重量相同时，多运动辅助更有利于降低代谢成本。实验测试表明，所提出的软外骨骼和控制算法是有效的步行辅助在负载条件下。然而，髋关节辅助装置的性能仅基于跑步机行走进行测试。在未来的研究中，我们将对软外骨骼在复杂道路环境下的性能进行评估。
Understanding the effects of different hip assistance modes is a fundamental step in the process of designing hip assistance devices and controllers that can provide better performance in terms of metabolic cost. We have developed and tested a soft exoskeleton for hip assistance, which includes three assistance modes: hip extension assistance (HEA), hip flexion assistance (HFA), and hip extension and flexion assistance (HEFA). A proportional derivative (PD) iterative learning controller based on the feedforward model was proposed to control the assistive force accurately. The three hip assistance modes were evaluated on seven male subjects walking on a treadmill at a speed of 5 km/h in two scenarios-first with a 15-kg backpack and then without any backpack. The net metabolic costs could be reduced during the loaded condition, compared with those under no exoskeleton condition, by 9.95%, 6.25%, and 15.28% for HEA, HFA, and HEFA, respectively. The reductions were found significant in HEA (p = 0.048) and HEFA (p = 0.005) modes, while the HFA mode (p = 0.202) was not found statistically significant. It indicates that the HEA and HEFA modes with the soft exoskeleton provide more benefit to the net metabolic cost compared with the HFA mode. The net metabolic costs reduced during the unloaded condition were 9.21%, 2.58%, and 13.05% for HEA, HFA, and HEFA, respectively. The improvements in the walking efficiency during both the conditions with the developed soft exoskeleton are demonstrated.Note to Practitioners-This article was motivated by the problem that how to reduce the metabolic cost most appropriately of walking by hip assistance of soft exoskeleton. In this article, we conduct a comparison of three hip assistance modes to discuss the balance of system weight and assistance efficiency. We then propose a PD iterative learning controller based on the feedforward model to track the desired assistive force accurately. Preliminary experiments suggest that the hip extension assistance (HEA) is more suitable than hip flexion assistance (HFA) for hip assistance during single motion assistance. Multiple motion assistance is more beneficial for metabolic cost reduction when the weight of the soft exoskeleton is the same. The experimental tests show that the proposed soft exoskeleton and the control algorithm are effective for walking assistance during the loaded condition. However, the performance of the hip assistance device is tested based on the treadmill walking only. In future research, we will conduct a performance evaluation of the soft exoskeleton on a complex road environment.