小柯机器人

人脚刚度与横向拱形的进化
2020-02-27 10:45

人脚刚度和横向拱形的进化,这一成果由英国华威大学Shreyas Mandre、日本冲绳理工学院Mahesh M. Bandi和耶鲁大学Madhusudhan Venkadesan课题组合作经过不懈努力而取得。该研究成果于2020年2月26日在线发表在《自然》杂志上。

研究人员发现横骨弓通跖骨间组织起作用,并承担足部纵向刚度的40%以上。其基本原理类似于一张软盘状纸币,当其横向卷曲时会明显变硬。研究人员推导了一个无量纲的曲率参数,该参数控制着横向骨弓的刚度,并用脚力学模型展示了其预测能力,并在人脚中发现了其骨骼相关性。在脚中,跖骨间组织的材料特性和跖骨的活动性可能会另外影响脚的纵向刚度,从而影响横向骨弓的曲率-刚度关系。通过分析化石,研究人员追踪了灭绝的古人类之间曲率参数的演变,阐述了与人类类似的双足弓是两足动物进化的关键步骤,智人两足动物的进化要比人类早至少150万年。对脚的这种新认识可能会改善扁平足疾病的临床治疗、改善机器人脚的设计以及运动中脚功能的研究。

研究人员表示,坚硬的人脚可以在行走或跑步时有效地下推,并且对于两足动物的进化至关重要。人们认为中足独特的弓形形态会使其变硬,而其他灵长类动物的扁平足会在中足严重弯曲。但是,足部生物力学、足病学和古生物学中,足中部几何形状与刚度之间的关系仍存在争议。这些争论集中在内侧纵弓上,但仍然未知人脚的第二个横向横弓是否会影响刚度。

附:英文原文

Title: Stiffness of the human foot and evolution of the transverse arch

Author: Madhusudhan Venkadesan, Ali Yawar, Carolyn M. Eng, Marcelo A. Dias, Dhiraj K. Singh, Steven M. Tommasini, Andrew H. Haims, Mahesh M. Bandi, Shreyas Mandre

Issue&Volume: 2020-02-26

Abstract: The stiff human foot enables an efficient push-off when walking or running, and was critical for the evolution of bipedalism1,2,3,4,5,6. The uniquely arched morphology of the human midfoot is thought to stiffen it5,6,7,8,9, whereas other primates have flat feet that bend severely in the midfoot7,10,11. However, the relationship between midfoot geometry and stiffness remains debated in foot biomechanics12,13, podiatry14,15 and palaeontology4,5,6. These debates centre on the medial longitudinal arch5,6 and have not considered whether stiffness is affected by the second, transverse tarsal arch of the human foot16. Here we show that the transverse tarsal arch, acting through the inter-metatarsal tissues, is responsible for more than 40% of the longitudinal stiffness of the foot. The underlying principle resembles a floppy currency note that stiffens considerably when it curls transversally. We derive a dimensionless curvature parameter that governs the stiffness contribution of the transverse tarsal arch, demonstrate its predictive power using mechanical models of the foot and find its skeletal correlate in hominin feet. In the foot, the material properties of the inter-metatarsal tissues and the mobility of the metatarsals may additionally influence the longitudinal stiffness of the foot and thus the curvature–stiffness relationship of the transverse tarsal arch. By analysing fossils, we track the evolution of the curvature parameter among extinct hominins and show that a human-like transverse arch was a key step in the evolution of human bipedalism that predates the genus Homo by at least 1.5 million years. This renewed understanding of the foot may improve the clinical treatment of flatfoot disorders, the design of robotic feet and the study of foot function in locomotion.

DOI: 10.1038/s41586-020-2053-y

Source: https://www.nature.com/articles/s41586-020-2053-y

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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