Decentralized Backstepping Control of a Quadrotor with Tilted-rotor under Wind Gusts

Conventional unmanned aerial vehicles, quadrotor have a plethora of applications for civilian and military purposes. Quadrotors as the name implies usually have four input variables (fixed rotors) which are used to drive six outputs (i.e., 3 translational and 3 rotational motions), and this leads to coupling between motions. Tilt- rotor quadrotors are more versatile because they have more input variables to independently control its orientation and position without coupling. In this paper, a decentralized backstepping control approach is used to generate a new set of inputs capable of independently and simultaneously achieve decoupling of motions while rejecting wind disturbances. The tiltrotor quadrotor dynamic is first decentralized to achieve six subsystems, then controller inputs for each subsystem are generated via Lyapunov based backstepping method whereby the controller parameters are optimized by Differential Evolution (DE) technique. This system exhibits robustness capability because it is able to reject external disturbances.