Design and Development of a Vector Thrusting Quadrotor for Minimally Induced Pitch and Roll Motions

Due to its hovering capabilites and maneuverability, the quadrotor provides an excellent platform for unmanned systems and robotics research. Localization of the vehicle is typically done via laser ranging or photometric and depth cameras. The design of the quadrotor introduces a problem, however, when it is to travel parallel to the ground plane. Due to the rigid body of the quadrotor and the fixed orientation of the thrusters it is impossible for the quadrotor to undergo this motion without inducing a change in the pitch and/or roll orientation. This introduces a problem in finding the true orientation at which sensor measurements are taken, requiring advanced computer vision algorithms, mechanical gimbal systems or other means to compensate for the motion. This paper focuses on the design of a quadrotor that has the capability to travel parallel to the ground plane while minimizing the induced pitch and roll motion. The unique contribution to the quadrotor design is to allow each of the quadrotor arms to rotate about their respective horizontal axis in order to accomplish thrust vectoring of the individual motors. By controlling both the magnitude and direction of each of the motor thrusts, pure translational maneuvers are possible without inducing pitch and/or roll motions. Simulation results are presented as well as the controller used to govern the behavior of the craft.