A miniature surface tension-driven robot mimicking the water-surface locomotion of water strider

Abstract

Aiming at mimicking water strider's water-surface locomotion, this study proposes a new miniature surface tension-driven robot. A key feature of this robot is that its actuating legs possess ellipse-like spatial trajectories like water strider by using a cam-link mechanism, and never pierces water surface when rowing. A set of simple models and equations are proposed to analyze the interaction forces between leg and water as well as the critical condition for a leg penetrating a water surface. The final fabricated robot weights about 3.9 g with a load capacity of 5.6 g. By controlling the motions of actuating legs, the robot can freely and stably walk on water with different gaits. The maximum forward and turning speeds of the robot are measured as 16 cm/s and 23 °/s, respectively. Moreover, a similarity analysis with Bond Number and Weber Number reveals that the locomotion of this robot is quite analogous to that of a water strider: surface tension force dominates the lifting force and plays a major role in the propulsion.

A continuous jumping robot on water mimicking water striders

“…For example, Sitti et al [8] designed a miniature water strider robot driven by a T-shaped actuating mechanism with three piezoelectric actuators. Yan et al [10] proposed a novel cam-link mechanism that can generate an ellipse-like spatial trajectory and ensure the actuating legs row on water without penetrating into water during the rowing stage.…”

“…At present, the research on water strider robots is mainly focused on mimicking its skating movement. Till now, A numerous of robots that can skate on water have been designed using superhydrophobic materials as supporting legs and actuating legs [6]- [10]. For example, Sitti et al [8] designed a miniature water strider robot driven by a T-shaped actuating mechanism with three piezoelectric actuators.…”

A water-walking robot mimicking the jumping abilities of water striders

“…At present, research on water-strider robots has mainly focused on mimicking the horizontal skating movement of the insect. Numerous robots that can skate on water have been designed by utilizing superhydrophobic supporting legs and actuating legs [6][7][8][9][10][11][12][13]. For example, Hu et al [6] proposed a mechanical water robot using elastic energy storage to drive its legs.…”

“…Sitti et al [7] designed a miniature water strider robot driven by a T-shaped actuating mechanism with three piezoelectric actuators. Zhang et al [8,9] proposed a novel cam-link mechanism that generates an ellipselike spatial trajectory and ensures that the actuating legs row on water without penetrating into the water during the rowing stage. A surface tension-driven robot processes locomotion analogous to that of a water strider, and this robot can stably move forward and make turns with different gaits on the water surface.…”