Concentric Precurved Bellows: New Bending Actuators for Soft Robots
Concentric Precurved Bellows: New Bending Actuators for Soft Robots
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DOI：
10.1109/lra.2020.2967323
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发表时间：
2020-04-01
影响因子：
5.2
通讯作者：
Rucker, Caleb
中科院分区：
文献类型：
--
作者：
Childs, Jake A.;Rucker, Caleb
提出了一种基于同心波纹管的柔性连续体机器人弯曲驱动器。每个波纹管在其底部轴向旋转，允许独立控制同心波纹管对的曲率和弯曲平面。旋转的嵌套管是一个众所周知的原则，针大小的同心管机器人的操作，但这个概念从来没有扩大到大直径，由于增加的驱动力，减少的运动范围，应变限制，和扭转卷取的权衡。在这封信中，我们表明，使用波纹管结构而不是管允许两个重要的突破：（1）可以在更大的尺度上实现通过旋转同心元件的致动，扭转滞后（即，当尖端处的相对管角度与基部处的相对管角度不同时）并且由于波纹管几何形状赋予的扭转刚度与弯曲刚度的高比率，扭转不稳定性实际上被消除。我们讨论了两种类型的3D打印同心波纹管原型（旋转和螺旋）的开发，进行模型参数识别，并通过实验验证了无扭转力学模型，该模型考虑了方向相关的刚度。
We present a new mechanical bending actuator for soft and continuum robots based on a pair of concentric precurved bellows. Each bellows is rotated axially at its base, allowing independent control of the curvature and bending plane of the concentric bellows pair. Rotation of precurved nested tubes is a well-known principle by which needle-sized concentric-tube robots operate, but the concept has never been scaled up to large diameters due to the trade-offs of increased actuation forces, decreased range of motion, strain limits, and torsional windup. In this letter, we show that using bellows structures instead of tubes allows two important breakthroughs: (1) actuation by rotation of precurved concentric elements can be achieved at much larger scales, and (2) torsional lag (i.e. when the relative tube angle at the tip differs from that at the base) and torsional instability are virtually eliminated due to the high ratio of torsional rigidity to flexural rigidity endowed by the bellows geometry. We discuss the development of two types of 3D printed concentric precurved bellows prototypes (revolute and helical), perform model parameter identification, and experimentally verify a torsionless mechanics model which accounts for direction-dependent rigidities.