A Robust Sliding-Mode Control Framework for Quadrotors Subject to Model Uncertainty and External Disturbances

In this study, we propose a novel control framework to deal with position control for quadrotors subject to time-varying disturbances and uncertainty. High-order sliding mode observers (HSMOs) are utilized to estimate the uncertainty and disturbances. Then, a dynamic sliding mode controller (DSM C) is presented for tracking control of the inner-loop subsystem and a fast non-singular terminal sliding mode controller (FNTSMC) is developed for outer-loop subsystem tracking control. As a result, our proposed control law enables the quadrotor to precisely track a large class of reference signals under the presence of model uncertainty and a large class of time-varying external disturbances while reducing the chattering phenomenon. Both simulation and experiment are given to validate the effectiveness and superiority of the designed controllers.