Nonlinear robust sliding mode control of a quadrotor unmanned aerial vehicle based on immersion and invariance method

We present an asymptotic tracking controller for an underactuated quadrotor unmanned aerial vehicle using the sliding mode control method and immersion and invariance based adaptive control strategy in this paper. The control system is divided into two loops: the inner-loop for the attitude control and the outer-loop for the position. The sliding mode control technology is applied in the inner-loop to compensate the unmatched nonlinear disturbances, and the immersion and invariance approach is chosen for the outer-loop to address the parametric uncertainties. The asymptotic tracking of the position and the yaw motion is proven with the Lyapunov based stability analysis and LaSalle's invariance theorem. Real-time experiment results performed on a hardware-in-the-loop-simulation testbed are presented to validate the good control performance of the proposed scheme. Copyright (C) 2014 John Wiley & Sons, Ltd.