Abstract
Fully soft bistable mechanisms have shown extensive applications ranging from soft robotics, wearable devices, and medical tools, to energy harvesting. However, the lack of design and fabrication methods that are easy and potentially scalable limits their further adoption into mainstream applications. Here a top-down planar approach is presented by introducing Kirigami-inspired engineering combined with a pre-stretching process. Using this method, Kirigami-Pre-stretched Substrate-Kirigami trilayered precursors are created in a planar manner; upon release, the strain mismatch -- due to the pre-stretching of substrate -- between layers would induce an out-of-plane buckling to achieve targeted three dimensional (3D) bistable structures. By combining experimental characterization, analytical modeling, and finite element simulation, the effect of the pattern size of Kirigami layers and pre-stretching on the geometry and stability of resulting 3D composites is explored. In addition, methods to realize soft bistable structures with arbitrary shapes and soft composites with multistable configurations are investigated, which could encourage further applications. Our method is demonstrated by using bistable soft Kirigami composites to construct two soft machines: (i) a bistable soft gripper that can gently grasp delicate objects with different shapes and sizes and (ii) a flytrap-inspired robot that can autonomously detect and capture objects.
Abstract (translated)
完全柔软的双向可控机制已经展示了广泛的应用,包括软机器人、可穿戴设备、医疗工具以及能源收集。然而,缺乏容易且可能可扩展的设计和制造方法限制了它们进一步融入主流应用。在这里,通过引入 Kirigami 灵感工程并结合预拉伸过程,提出了一种自上而下的平面方法。通过这种方法, Kirigami 预拉伸的基板-Kirigami 三层前体在平面上创建;一旦释放,由于基板预先拉伸,layers 之间的应力不匹配将引发平面Buckling,以实现目标的三维双向结构。通过结合实验表征、分析建模和有限元模拟,探索了 Kirigami 层和预拉伸对 resulting 3D 复合材料几何稳定性的影响。此外,探索了实现任意形状和多态结构的软双向结构和软复合材料的方法,这可能会鼓励进一步应用。我们的方法通过使用双向软 Kirigami 复合材料构建两个软机器:(i)一个双向软抓手,能够轻轻地抓住具有不同形状和大小的精细物体,(ii)一个模仿飞盘机器人,能够自主地检测并捕捉物体。
URL
https://arxiv.org/abs/2301.09179
