Attitude Control of Unmanned Aerial Vehicle Based on Sliding Mode Technique with Parameter Estimation

An adaptive robust controller for nonlinear and coupling dynamic of aerial vehicle has been presented. In this paper an adaptive sliding mode controller (ASMC) is integrated to design the attitude control for the inner loops of nonlinear coupling dynamic of Unmanned Aerial Vehicle (UAV) in the presence of parametric uncertainties and disturbances. In the proposed scheme, the adaptation laws can estimate the unknown uncertain parameters and external disturbances, while the sliding mode control is used to ensure the fast response and robustify the control design against unmodeled dynamics with a small control effort.The synthesis of the adaptation laws is based on the positivity and Lyapunov design principle.  In comparison with other sliding mode approaches, the approach does not need the upper bound of parametric uncertainty and disturbances. The navigation outer loops of small UAV instead is based on PIDs to control altitude and heading. Simulation results demonstrate that the proposed controller can stabilize the nonlinear system and also it has stronger robustness with respect to the model uncertainties and gust disturbance.