Non-cascade Adaptive Sliding Mode Control for Quadrotor UAVs under Parametric Uncertainties and External Disturbance with Indoor Experiments

In the field of unmanned aerial vehicles (UAVs), quadrotors are receiving considerable attention because of their potential application to industries such as transportation, inspection, and search and rescue. One of the key challenges is to robustly control the position and attitude of a UAV amid the mass and inertia uncertainties, as well as the external disturbances, that exist in the real environment. To meet these demands, this paper proposes a non-cascade adaptive sliding mode control (SMC) strategy for quadrotor trajectory tracking control. To represent real flight conditions, system dynamics are developed with unknown mass and moment of inertia while external disturbances are taken into account. Numerical simulation and indoor flight experiments are performed to verify the effectiveness of the proposed adaptive SMC strategy. In the indoor experiments, to illustrate robustness several experiments are carried out to compare the proposed design with the conventional cascade structure controller: (1) inherent inertia uncertainty, (2) mass uncertainties plus (1), and (3) external disturbance plus (2).