Robust path tracking of a quadrotor using adaptive fuzzy terminal sliding mode control

With the increasing use of quadrotors, the design of flight control systems has become particularly important. In this paper, a new robust flight control system consisted of an adaptive fuzzy terminal sliding mode controller, and two proportional-derivative (PD) controllers are proposed to stabilize a quadrotor and to track a pre-defined flight path in the presence of external disturbances and model uncertainties. The PD controllers determine the desired attitude of the quadrotor and terminal sliding mode control adjusts the rotation speed of rotors. The dynamics of the quadrotor and external disturbances are identified online by applying adaptive Mamdani fuzzy systems. Also, the control chattering is eliminated by defining a continuous terminal sliding mode. Two Kalman filters are also utilized to improve the estimation of the quadrotor attitude and position. The simulation results and real-time implementation of the proposed flight control system show the efficient performance of the control system during two flight scenarios of the quadrotor.