Backstepping trajectory tracking control of a quadrotor with disturbance rejection

This paper presents a trajectory tracking controller based on the backstepping technique. To avoid the increasing complexity of analytically calculating the derivatives of the virtual control signals in standard backstepping control, a command filtered backstepping approach is utilized. The command filtered backstepping controller is modified to include integral action to increase robustness against external disturbances and unmodeled dynamics. The stability proof of the command filtered integral backstepping approach is presented based on Lyapunov's theorem. The controller is implemented on a quadrotor unmanned aerial vehicle in simulation and compared to a standard integral backstepping controller. Simulation results show that the presented controller yields an improvement in the tracking performance of the quadrotor in the presence of constant disturbances and unmodeled actuator dynamics with lower control effort.