The WiFly: Flapping-Wing Small Unmanned Aerial Vehicle with Center-of-Gravity Shift Mechanism

This paper describes the development of a flapping-wing unmanned aerial vehicle (UAV) named WiFly, which is equipped with a center-of-gravity (COG) shift mechanism. This mechanism allows seamless changes in the flight attitude between hovering and level flight by controlling the pitch angle. We implemented two types of feedback control systems in WiFly: PID control and reinforcement learning (shallow Q-learning) to stabilize the flight attitude. The controllability of WiFly is drastically improved by employing a double-motor drive system to independently control the flipping frequencies of the left and right wings.