Lecomte Christophe, Ármannsdóttir Anna Lára, Starker Felix, Tryggvason Heimir, Briem Kristin, Brynjolfsson Sigurður
Össur hf., Grjótháls 5, 110, Reykjavik, Iceland; Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, Reykjavík, Iceland.
Department of Physical Therapy, School of Health Sciences, University of Iceland, Reykjavik, Iceland.
J Biomech. 2021 Jun 9;122:110440. doi: 10.1016/j.jbiomech.2021.110440. Epub 2021 Apr 14.
Energy storing and returning prosthetic feet are commonly prescribed. Research has demonstrated advantages to use these types of prosthetic feet. However, their stiffness in the sagittal plane is fixed and cannot adapt to different walking tasks and user preference. In this paper, we propose a novel prosthetic foot design capable of modulating its stiffness in the sagittal plane. The Variable Stiffness Ankle unit (VSA) is mounted on a commercially available prosthetic foot. The stiffness of the foot is adjusted with a lightweight servo motor controlled wirelessly. The stiffness change is accomplished by moving the supports points on the glass fiber leaf spring of the VSA ankle unit. We described the design and characterized changes in ankle stiffness using a mechanical test bench. A novel method was used to capture mechanical test data using a six degree of freedom load cell, allowing us to contrast mechanical and biomechanical data. A transtibial unilateral amputee performed level ground walking on an instrumented treadmill. The VSA prosthetic foot exhibited ankle stiffness change in the mechanical test bench. Ankle stiffness changes were also confirmed during the biomechanical analysis. Future work will involve additional subjects. The VSA prosthetic foot could improve user satisfaction and help prosthetist to fine tune prosthetic feet during fittings.
储能和回能假肢脚是常用的。研究已经证明了使用这类假肢脚的优势。然而，它们在矢状面的刚度是固定的，无法适应不同的行走任务和用户偏好。在本文中，我们提出了一种能够在矢状面调节其刚度的新型假肢脚设计。可变刚度踝关节单元（VSA）安装在市售的假肢脚上。通过无线控制的轻质伺服电机来调节脚的刚度。刚度的改变是通过移动VSA踝关节单元玻璃纤维板簧上的支撑点来实现的。我们使用机械试验台描述了该设计并表征了踝关节刚度的变化。一种新颖的方法被用于使用六自由度测力传感器采集机械测试数据，使我们能够对比机械和生物力学数据。一名经胫骨单侧截肢者在装有仪器的跑步机上进行了平地行走。VSA假肢脚在机械试验台上表现出踝关节刚度的变化。在生物力学分析过程中也证实了踝关节刚度的变化。未来的工作将涉及更多受试者。VSA假肢脚可以提高用户满意度，并帮助假肢师在装配过程中对假肢脚进行微调。
