Global Sliding Mode Control for a Fully Actuated Non-planar Hexarotor Aerial Vehicle

This work is concerned with the attitude and position control of a fully actuated non-planar hexarotor aerial vehicle equipped with reversible fixed rotors. The complete nonlinear dynamics of the vehicle is modeled in a state error formulation with six degrees of freedom (DOF), being three for position and three others for attitude, while the control input is also a six-DOF quantity defined in terms of the resultant force and torque acting on the system. A control law is designed using an unit-vector global sliding mode control strategy, which ensures robustness against bounded force and torque disturbances during the entire flight since the sliding condition is guaranteed from the initial time. Furthermore, the proposed controller also ensures global exponential stability for both the closed-loop translational and rotational dynamics. Using computational simulations, the designed control law is compared with an inverse-dynamic stabilizing control, showing to be effective and to perform much better.