Entwurf eines Flugreglers für ein vierrotoriges unbemanntes Fluggerät - Control Systems Design for a Quadrotor UAV

This paper describes the design of a nonlinear control system for a small four-rotor aerial
robot, a so called quadrotor UAV (unmanned aerial vehicle). Stabilizing control of these
vehicles is a difficult task because of the nonlinear dynamic behavior. The proposed
control system is based on a decomposition into an inner attitude and an outer velocity
control loop. For the attitude control, feedback linearization is applied that transforms
the system into a decoupled linear system in state variable format. This resulting system
is controlled via a conventional linear controller, leading to a sufficiently fast and
damped closed loop dynamics. The outer control loop applies a nonlinear inversion to
compensate a static nonlinearity and a linear control system to control the remaining
linear dynamics. The advantage of the derived control system besides the excellent
performance is the simple structure and the easy implementation.