Cooperative Backstepping Control of Quadrotors via Sliding Mode Observer

This paper is mainly about backstepping control by running parallel sliding mode observer for a quadrotor Unmanned Ariel Vehicle. This sliding mode observer is filtered by a low pass filter to improve the performance of the observer. Forasmuch as filtering sliding mode outputs eliminates stimulated discontinuity of the sign function of observer, smooth results achieved. This observer will estimate the disturbances and observe the velocities (𝑥̇,𝑦̇,𝑧̇,𝜙̇,𝜃̇,𝜓̇) of the quadrotor. The controller is intended to reach desired position (𝑥,𝑦,𝑧) and yaw angle (𝜓) while tilt angles (𝜙,𝜃) restrains stable and velocities are engaged by bounded external disturbances; however, whole system remains stable. In addition to verifying efficiency of the method, simulation results show the good performances of tracking and robustness of the studied observer-controller.