Hoverability Analysis and Development of a Quadrotor Only with Clockwise Rotors

This paper presents novel quadrotor structures composed of only clockwise rotors. A multirotor unmanned aerial vehicle (UAV) generally has both clockwise and counterclockwise rotors to counteract the torques from the rotors. While the proposed structures have only clockwise rotors, those rotors are tilted to cancel the torques around the yaw angle of the body. This paper investigates the conditions for the proposed structures to achieve static hovering. More specifically, we provide a guideline to design the rotor tilt angles of the proposed structure. Then, this paper presents the design example of the rotor tilt angles and develops a prototype of the proposed quadrotor. The cascaded controller is also developed for the proposed structure. Finally, experimental validation is conducted with a developed prototype and controller.