Research of precision flight control for quadrotor UAV

For quadrotor unmanned air vehicles (UAVs) flight stability under external disturbances, a hybrid controller design approach is presented to realize robust control. The hybrid controller consists of an inner-loop attitude controller and an outer-loop position controller. A nonlinear Backstepping controller is implemented for the inner stabilization loop. A fuzzy adaptive PD composite controller is used for the outer loop. The outer loop controller generates the reference trajectories for the inner loop controller to reach the desired waypoint. Numerous simulations and flight test experiments have been performed using the hybrid control algorithm. The results illustrate that the proposed controller can estimate disturbances online and improve the robustness of the system.