Adaptive nonsingular terminal sliding mode tracking control of quadrotor systems with mass uncertainties and input delay

This paper focuses on tracking control of quadrotor systems in the presence of mass uncertainty and input delay, which arises from complex operational environment of the quadrotor systems. Input delay and the model uncertainty caused by mass change could affect the quadrotor's stability and mitigate the tracking accuracy of unmanned aerial vehicle (UAV) flight control. To remove the detriment of input delay and eliminate the negative effect of uncertain mass, an adaptive sliding mode controller based on state prediction is proposed in this paper. Lyapunov stability theory is utilized to guarantee the asymptotic stability of the tracking error. Finally, simulation results are provided to manifest the validity and feasibility of the proposed control strategy.