Design and implementation of a structured flight controller for a 6DoF quadrotor using quaternions

This paper describes a practical implementation of simple control algorithms on a 6DoF quadrotor flying in an uncontrolled environment and being equipped with inexpensive sensors. A significant number of control algorithms that apply dynamic inversion or backstepping techniques on simplified state variable models of the vehicle dynamics are present in the literature, but they are only tested in simulations where real-life issues like sensor noise and precision, vibrations, measurement reference frames, and modeling errors are not included completely or even partially. Here it is shown that if the practical implementation is done correctly, even simple PD controllers can ensure the stability of the quadrotor platform in hover.