Design and Implementation of a Quadrotor-Based Spherical Robot

Spherical robots have many advantages compared with traditional wheeled and orbital robots. In this paper, the design and implementation of a novel quadrotor-based spherical robot is presented. The robot, named FBall, consists of a spherical outer shell made of Polymethacrylimide (PMI) foam, four variable-pitch propellers, four motors, a controller and a battery. The robot is capable of rolling on water surfaces, rolling on ground surfaces and flying in the air by changing the pitch angle of each propeller and adopting corresponding control algorithms. In rolling mode, two propellers’ pitch angle are set to negative values, and the other two are set to positive values so as to provide a rolling moment. In the flying mode, the pitch angle of all the propellers are set to the same value just as traditional quadrotors, and 4 PID controllers are employed to regulate its roll, pitch, yaw angles, and altitude.The paper focuses primarily on designing a spherical robot based on a variable pitch quadrotor. Modeling, locomotion capabilities analyzing and future works are also presented.