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.

翻译：全软体双稳态机构在软体机器人、可穿戴设备、医疗工具乃至能量收集等领域展现出广泛应用前景。然而，缺乏简便且潜在可扩展的设计与制备方法，限制了其在主流应用中的进一步推广。本文提出一种自上而下的平面方法，通过引入受Kirigami启发的工程学设计与预拉伸工艺相结合。利用该方法，以平面方式制备了Kirigami-预拉伸基底-Kirigami三层前驱体；释放后，由于基底预拉伸导致的层间应变失配会诱发面外屈曲，从而形成目标三维双稳态结构。通过结合实验表征、解析建模与有限元仿真，系统探究了Kirigami层图案尺寸与预拉伸量对所得三维复合结构几何形态及稳定性的影响。此外，还研究了实现任意形状软体双稳态结构及多稳态构型软体复合材料的方法，这有望推动其进一步应用。我们通过两种软体机器装置验证了该方法：（i）一种可轻柔抓取不同形状与尺寸易碎物体的双稳态软体夹持器；（ii）一种可自主检测并捕获物体的捕蝇草仿生机器人。