Modeling and sliding mode-based attitude tracking control of a quadrotor UAV with time-varying mass

In the practical applications, the mass of a quadrotor unmanned aerial vehicle (UAV) would be time-varying. This time-varying mass will deteriorate the control performance of UAV. To solve this challenge, the mathematical modeling problem of a quadrotor UAV with time-varying mass is first investigated in this paper. The nonlinear dynamics describing the six-degrees-of-freedom full motion is established. Based on the established model, taking attitude tracking control problem into consideration, a robust control scheme is then designed via the sliding mode control theory. Applying the developed proposed approach, the desired trajectory is followed with the attitude tracking error asymptotically stabilized. The proposed controller has the capability of rejecting the external disturbance and the uncertainties induced by the time-varying mass. The feasibility of the established model and the effectiveness of the presented control approach are validated through a simulation study.