Energy efficient perching and takeoff of a miniature rotorcraft

The flight time of aircraft rapidly decreases with smaller scales because the lift-to-drag ratio decreases when scaling down. Aerial-surface locomotion, or perching is one energy efficient solution to prolong the fight time by maintaining the drone at a high vantage point. Current perching strategies require additional components to ensure robots firmly attach to the surfaces, and able to detach afterwards, resulting in increased power consumption owing to the added weight. Here, we report a 32-g rotorcraft with the ability to repeatedly perch and take off from overhangs and walls on different wet and dry substances. A propelling thrust is used to support the robot to keep rotorcraft balance against the surface. Integrating with the mussel-inspired wet adhesives, the rotorcraft dispenses the additional components required for attachment and taking off. The final rotorcraft is 32.15 g, only 1.09 g heavier than the original prototype, but shows a 50% and 85% reduction in power consumption when perching on ceilings and walls respectively. The saved power leads to a fourfold increase in the total mission time.