Attitude control for tilt rotorcraft based on sliding mode containing disturbance observer

Abstract

For the quad tilt rotor (QTR) aircraft in the wind field disturbance, considering the influence of model uncertainties and external disturbances on attitude control, a sliding mode control method based on terminal sliding mode theory, new reaching law and super twisting disturbance observer is proposed. Firstly, by using the advantages of nonsingular terminal sliding mode in finite time convergence and robustness, the fast nonsingular terminal sliding surface is introduced. Second, a new double power reaching law with two order sliding mode characteristics, which can effectively suppress chattering, is proposed. Third, the super twisting disturbance observer is designed to realize the estimation and compensation of the complex disturbance. Simulation results show that, compared with the conventional nonsingular terminal sliding mode control strategy, the proposed control scheme has good control performance in the presence of modeling errors and complex disturbances.