Takeoff of an all-polymer micro aerial flying robot.

Flying insects are agile and can withstand impacts and compression because of their low inertia and resilient wings, exoskeletons, and muscles. These capabilities inspire the development of micro aerial vehicles (MAVs) for surveillance, disaster response, and environmental monitoring in confined or hazardous spaces. However, MAVs, especially subgram flapping-wing platforms, remain fragile because they rely on rigid components in their wings, transmissions, or actuators. We report a resilient all-polymer flying robot weighing 185 milligrams, powered by an electrostrictive bending actuator that directly drives cone-shaped compliant wings without a transmission. The actuator achieves a power density of 1600 watts per kilogram and a bending angle of 136° at 110 hertz, enabling the flying robot to achieve a lift-to-weight ratio of 3.0 and a lift-to-power ratio of 8.3 millinewtons per watt at 30 hertz. The robot demonstrates unaided takeoff with an average ascending speed of 40 centimeters per second. Thanks to its compliant and transmission-free structure, the robot can resume flight after being hit by a flyswatter or flattened by heavy loads. The robot design features mechanical simplicity and resilience, promising a paradigm for subgram flight in harsh environments.