A surface tension-dominated biomimetic water strider robot for skating on the water

The diversity of insect movements constitutes a key survival mechanism for obstacle avoidance and predatory escape behavior. As a representative aquatic insect, the water strider can skate quickly and freely on the water surface while ensuring its integrity. Utilizing this phenomenon, we propose a surface tension-dominated biomimetic water strider robot that can perform motion (linear skating and turning motion) on the gas–liquid interface. The robot has a maximum linear velocity of 14.2 cm/s and a maximum turning speed of 13.5 °/s. Compared to water pressure-dominated surface skating robots, this robot has the advantage of minimal surface disturbance. At the same time, the robot utilizes a combination of incomplete gear and face gear mechanical structures to achieve composite motion of the driving leg in both vertical and horizontal directions, restoring the spatial elliptical travel trajectory of the biological water strider driving leg end. In addition, this study also analyzed the fluid dynamics mechanism between the robot's driving legs and the water surface, as well as the stability of the water surface motion. This study provides new design criteria for the development of biomimetic water strider robots.