Propulsion and steering of a floating mini-robot based on Marangoni flow actuation

This paper discusses the propulsion and steering of a floating mini-robot based on thermal Marangoni flow. The normal component of the surface tension force keeps the robot floating on the liquid surface, while the localized heating of liquid surface results in tangential Marangoni flows which propel the robot. Lift force modeling shows that six legs of 1 cm long and 300 mum in diameter generate a lift force of 7.56 mN. Simulations suggest that a propulsion force of 0.638 mN per leg can be generated for a heater temperature of 60degC. Preliminary experiments using a 2times1.5 cm² H-shaped structure demonstrate that a velocity of 4.4 mm/sec and a rotational velocity of 0.2 rad/sec can be achieved.