Control Systems Design for a Quadrotor UAV

Abstract

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 non-linearity 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.