Event

Single-Motor Underactuated Drone Open-Sourced: One Motor Controls Thrust and Attitude

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Reddit user u/J_BlRD built and open-sourced an underactuated drone that flies with only one motor, using the same motor to simultaneously generate thrust and control pitch and roll. Its propeller hub is 3D-printed in PPA-CF and features hinges; when the motor accelerates, the blades lag, causing one side to pitch up and the other to pitch down; the author says attitude control is achieved through torque pulses timed to the rotor angle at 300 times per second. Because at close to 20,000 RPM a 0.2ms control loop already corresponds to the rotor turning 20 degrees, the author wrote custom firmware for the motor controller to compute the torque pulses on board. The fuselage slowly rotates on its own, and the drone obtains heading by seeing infrared "lighthouse" beacons in the corners of the room once per revolution. The code and CAD have been open-sourced on GitHub.