Inspired by the snap-through action of a steel hairclip, we propose a design method for in-plane prestressed mechanisms that exhibit biomimetic morphing and high locomotion performance. Compliant bistable flapping mechanisms are fabricated using this method and are mounted on our untethered soft robotic fish. Using this mechanism, we achieve life-like undulation with a Strouhal number (1) of St = 0.28 and a velocity of 2.03 body lengths per second (43.6 cm/s), a three-fold improvement over past compliant fish robots. A tethered pneumatic version indicates that this mechanism is compatible with soft actuators. We study the mechanism both computationally and experimentally and suggest that elastic instability may offer a path to overcome the speed challenge of soft and compliant robots.

翻译：受钢制发夹的“啪嗒”动作启发，我们提出了一种面向面内预应力机构的设计方法，该类机构具有仿生变形能力与高运动性能。利用该方法制造了顺应性双稳态扑翼机构，并将其安装于我们的无系留软体仿生鱼上。借助此机构，我们实现了斯特劳哈尔数（1）St=0.28、速度为2.03体长/秒（43.6厘米/秒）的逼真波动运动，速度是过去顺应性仿生鱼机器人的三倍。一种有系留气动版本表明该机构与软体驱动器兼容。我们通过计算与实验相结合的方式研究该机构，并指出弹性失稳或许能为克服软体与顺应性机器人的速度难题提供一条新路径。