Arbitrary Attitude Hovering Control of Quad Tilt Rotor Helicopter

[abstFig src='/00280003/08.jpg' width=""300"" text='Arbitrary attitude hovering' ] The quad tilt rotor helicopter (QTRH), a tilt-rotor aircraft prototype, has fixed wings for long-range high-speed flight. Its rotor-tilt mechanism controls 4 rotor-tilt angles independently and controls its roll and pitch angles similarly to a multirotor helicopter. It controls yaw angle by thrust vectoring and moves forward and backward by tilting its rotors. Rotor-tilting maneuvers are the initial stage of flight-mode transition between helicopter and fixed-wing modes.