Adaptive nonsingular fast terminal sliding mode control for aircraft with center of gravity variations

The center of gravity variations have a direct impact on the dynamic and the quality characteristics of the aircraft, which makes the control of the aircraft more difficult after center of gravity shifting. In order to solve this problem, an aircraft model that can simulate both the instantaneous and gradual center of gravity shift has been built as research object. Based on this model, an adaptive nonsingular fast terminal sliding mode controller is proposed to control the research object. Fast nonsingular terminal sliding mode has been combined with adaptive control method in the controller, in which the improved attractor can eliminate the chattering phenomenon and the nonlinear adaptive law can compensate the system disturbance caused by the center of gravity variation. The stability of closed loop is proved by using Lyapunov stability theory. The simulation results show that the proposed controller can realize the fast and precise track of the command.