A Hovering Flapping-Wing Microrobot with Altitude Control and Passive Upright Stability

The Harvard RoboBee is the first insect-scale flapping-wing robot weighing less than 100 mg that is able to lift its own weight. However, when flown without guide wires, this vehicle quickly tumbles after takeoff because of instability in its dynamics. Here, we show that by adding aerodynamic dampers, we can can alter the vehicle's dynamics to stabilize its upright orientation. We provide an analysis using wind tunnel experiments and a dynamic model. We demonstrate stable vertical takeoff, and using a marker-based external camera tracking system, hovering altitude control in an active feedback loop. These results provide a stable platform for both system dynamics characterization and unconstrained active maneuvers of the vehicle and represent the first known hovering demonstration of an insect-scale flapping-wing robot.