Modeling, Control and Experimentation of a Variable Pitch Quadrotor

Abstract: The aim of this thesis is to present a novel quaternion based control scheme for the attitude control problem of a quadrotor equipped with Variable Pitch Propellers. A quaternion is a hyper complex number of rank 4 that can be utilized to avoid the inherent geometrical singularity when representing rigid body dynamics with Euler angles or the complexity of having coupled differential equations with the Direction Cosine Matrix (DCM). In the presented approach the quadrotor's attitude model, Variable Pitch model and the proposed non-linear Proportional squared ($P^{2}$) control algorithm have been implemented in the quaternion space, without any transformations nor calculations in the Euler angle space nor the DCM space. Throughout the thesis, the merits of the proposed novel approach are being analyzed and discussed, while the efficiency of the suggested novel quaternion based controller and the use of Variable Pitch Propellers are being evaluated by extended simulation and experimental results.