Unmanned Aerial Vehicles: Embedded Control

Chapter 6

Control of Different UAVs with Tilting Rotors ¹

6.1. Introduction

The growing interest in the design of mini UAVs (unmanned aerial vehicles) for military and civilian applications has encouraged the industry and research community to come up with new designs, aiming at more efficient configurations in terms of size, discretion and energy. Another important aspect is the reliability of the autonomous attitude-stabilized flight, which has capital importance during reconnaissance and surveillance missions, where the goal is to provide a visual perspective of “blind” areas (around the corner, over the hill). In these missions, the 3D position is usually remotely controlled through an on-board camera, whereas the 3D attitude is computer-controlled.

Aerial robots with rotors-tilting capabilities represent an interesting research alternative within the category of VTOL mini UAVs, since this design allows us to generate additional torques, enabling the reduction of rotors as well as the size of the vehicle. Several authors have addressed this topic proposing and implementing new configurations. The dual tilting rotor presented by Gress [GRE 02] features two tilting rotors to control the 3D attitude of the rotorcraft. The corresponding mathematical model contains dynamic couplings and nonlinear terms, which relatively complicates the controller design. However, the proposed configuration provides a good compromise between stability and maneuverability. Concerning triple-rotor ...