Adaptive Fuzzy Sliding Mode Position and Attitude Control for a Quadrotor UAV

In this study, a new methodology based on the adaptive fuzzy sliding mode control method is introduced to track the position and attitude of a quadrotor UAV. Firstly, the dynamic model of the quadrotor is divided into an underactuated and a fully actuated subsystems. By combining the position and velocity tracking errors of one state variable, a sliding surface of fully actuated subsystem with two coefficients is defined. However, a sliding surface of underactuated subsystem is constructed via a linear combination of position and velocity tracking errors of two state variables with four coefficients. This methodology considers the Hurwitz stability theorem for obtaining the nonlinear coefficients of the sliding surface of underactuated subsystem. In addition, the flight controllers are derived by using mathematical theories, which guarantees that the closed-loop system is the global asymptotic stable in the presence of structured and un-structured uncertainties. Furthermore, in order to eliminate the control chattering phenomenon, the adaptive fuzzy approximator is used. The effectiveness of the proposed control method in the position and attitude tracking of a quadrotor is demonstrated through two set of simulation results, which shows its superior performance.