Magnetically induced stiffening for soft robotics.
Magnetically induced stiffening for soft robotics.
复制标题
软机器人的磁感应硬化。
DOI：
10.1039/d2sm01390h
复制
发表时间：
2023
期刊：
影响因子：
3.4
通讯作者：
Ranzani,Tommaso
中科院分区：
文献类型：
--
作者：
Gaeta,LeahT;McDonald,KevinJ;Kinnicutt,Lorenzo;Le,Megan;Wilkinson-Flicker,Sidney;Jiang,Yixiao;Atakuru,Taylan;Samur,Evren;Ranzani,Tommaso
软机器人非常适合于以人为中心的应用，但赋予软机器人这一优势的合规性也必须与足够的刚度调制相结合，以便软机器人在需要时能够实现更大的刚性。因此，变刚度机构往往是软机器人设计中必不可少的组成部分。为了将变刚度结构引入到软机器人中，人们已经探索了许多技术，如气动控制干扰和热控相变材料。尽管响应时间很快，但干扰方法通常需要更笨重的气动压力管，这限制了便携性；虽然通过电子控制进行便携，但热诱导方法需要与高温兼容，而且通常响应时间较慢。在本文中，我们提出了一种磁控加固方法，它将基于干扰的加固原理与磁流变液相结合，创建了一种机械和材料相结合的方法。在这样做的过程中，我们结合了气动干扰的快速响应时间的优势和热诱导相变方法的便携性。我们从两个方面探讨了磁场强度对磁流变干扰束样品硬化的影响：利用磁流变液屈服应力的增加，以及利用永磁体之间的夹持力通过离合器效应进一步使样品变硬。我们引入了一个分析模型来预测样品的硬度作为磁场的函数。最后，我们演示了使用电磁永磁体对刚度进行电子控制的方法。通过这种方式，我们向一种新的电子驱动的僵化机构迈出了重要的一步，这种机制用于软机器人，在与人类的近距离接触中安全互动，例如在可穿戴设备中。
Soft robots are well-suited for human-centric applications, but the compliance that gives soft robots this advantage must also be paired with adequate stiffness modulation such that soft robots can achieve more rigidity when needed. For this reason, variable stiffening mechanisms are often a necessary component of soft robot design. Many techniques have been explored to introduce variable stiffness structures into soft robots, such as pneumatically-controlled jamming and thermally-controlled phase change materials. Despite fast response time, jamming methods often require a bulkier pneumatic pressure line which limits portability; and while portable via electronic control, thermally-induced methods require compatibility with high temperatures and often suffer from slow response time. In this paper, we present a magnetically-controlled stiffening approach that combines jamming-based stiffening principles with magnetorheological fluid to create a hybrid mechanical and materials approach. In doing so, we combine the advantages of fast response time from pneumatically-based jamming with the portability of thermally-induced phase change methods. We explore the influence of magnetic field strength on the stiffening of our magnetorheological jamming beam samples in two ways: by exploiting the increase in yield stress of magnetorheological fluid, and by additionally using the clamping force between permanent magnets to further stiffen the samples via a clutch effect. We introduce an analytical model to predict the stiffness of our samples as a function of the magnetic field. Finally, we demonstrate electronic control of the stiffness using electropermanent magnets. In this way, we present an important step towards a new electronically-driven stiffening mechanism for soft robots that interact safely in close contact with humans, such as in wearable devices.