Surface tension driven water strider robot using circular footpads

Water strider insects have attracted many researchers' attention with their power efficient and agile water surface locomotion. This study proposes a new water strider insect inspired robot, called STRIDE II, which uses new circular footpads for high lift, stability, payload capability, and a new elliptical leg rotation mechanism for more efficient water surface propulsion. The lift, drag and propulsion forces and the energy efficiency of this robot are modeled and experiments are conducted to verify these models. A maximum lift capacity of 53 grams is achieved with a total of 12 footpads, each 4.2 cm in diameter for a robot weighing 21.75 grams. For this robot, a propulsion efficiency of 22.3% is measured. Maximum forward and turning speeds of the robot are measured as 71.5 mm/sec and 0.21 rad/sec, respectively. These water strider robots could be used in water surface monitoring, cleaning, and analysis in lakes, dams, rivers and sea.