Fuzzy uncertainty observer based filtered sliding mode trajectory tracking control of the quadrotor

In this paper, a filtered sliding mode control (FSMC) scheme based on fuzzy uncertainty observer (FUO) for trajectory tracking control of a quadrotor unmanned aerial vehicle (QUAV) is proposed. To be specific, the dynamics model of QUAV is decomposed into three subsystems. By virtue of the cascaded structure, sliding-mode-based virtual control laws can be recursively designed. In order to remove the smoothness requirements on intermediate signals, a series of first-order filters are employed to reconstruct sliding mode control signals together with their first derivatives. Moreover, fuzzy uncertainty observers are employed to indirectly estimate lumped unknown nonlinearities including system uncertainties and external disturbances and make compensation for the QUAV system. Stability analysis and uniformly ultimately bounded tracking errors and states can be guaranteed by the Lyapunov approach. Simulation studies demonstrate the effectiveness and superiority of the proposed tracking control scheme.