Horizontal Fixed Attitude Flight of Quad Rotor Helicopter with Tilting Rotor

A quad rotor helicopter (QRH), a type of unmanned aerial vehicle (UAV), uses a tilted attitude to generate a horizontal thrust component in the flying direction. In the case of autonomous control, the attitude control system is used to tilt the airframe against disturbances such as crosswinds. Consequently, the flying attitude of a QRH is always inclined. In this study, a tilting mechanism for rotors (TMR) was mounted on a QRH to maintain a horizontal attitude. The TMRs were tilted to generate thrust against disturbances without inclining the airframe. The system was constructed using a QRH and TMRs tilted around only one axis and allocated every 90°. Because the airframe is always horizontal, this system can be used for the precise measurement of landforms and buildings. This paper reports the dynamic modeling of QRH equipped with TMRs and discusses the horizontal constant attitude flight using the proposed system.