Amphibians adapt their morphologies and motions to accommodate movement in both terrestrial and aquatic environments. Inspired by these biological features, we present PuffyBot, an untethered shape morphing robot capable of changing its body morphology to navigate multiple environments. Our robot design leverages a scissor-lift mechanism driven by a linear actuator as its primary structure to achieve shape morphing. The transformation enables a volume change from 255.00 cm3 to 423.75 cm3, modulating the buoyant force to counteract a downward force of 3.237 N due to 330 g mass of the robot. A bell-crank linkage is integrated with the scissor-lift mechanism, which adjusts the servo-actuated limbs by 90 degrees, allowing a seamless transition between crawling and swimming modes. The robot is fully waterproof, using thermoplastic polyurethane (TPU) fabric to ensure functionality in aquatic environments. The robot can operate untethered for two hours with an onboard battery of 1000 mA h. Our experimental results demonstrate multi-environment locomotion, including crawling on the land, crawling on the underwater floor, swimming on the water surface, and bimodal buoyancy adjustment to submerge underwater or resurface. These findings show the potential of shape morphing to create versatile and energy efficient robotic platforms suitable for diverse environments.

翻译：两栖动物通过调整其形态和运动方式以适应陆地和水生环境中的移动。受这些生物学特征的启发，我们提出了PuffyBot，一种能够通过改变身体形态以在多种环境中导航的无缆形状变形机器人。我们的机器人设计采用由线性驱动器驱动的剪式升降机构作为其主要结构，以实现形状变形。该变形使机器人体积从255.00 cm³变化至423.75 cm³，通过调节浮力以抵消因机器人330 g质量产生的3.237 N向下力。一个曲柄连杆机构与剪式升降机构集成，可将伺服驱动的肢体调整90度，从而实现爬行与游泳模式之间的无缝切换。该机器人完全防水，使用热塑性聚氨酯（TPU）织物确保其在水生环境中的功能性。机器人搭载1000 mA h的机载电池，可无缆运行两小时。我们的实验结果展示了多环境运动能力，包括陆地爬行、水下地面爬行、水面游泳，以及通过双模态浮力调节实现水下潜没或上浮。这些发现表明，形状变形技术具有创建适用于多样化环境、多功能且高能效机器人平台的潜力。