Command Filter-Based Discrete-Time Adaptive Fuzzy Output Feedback Backstepping Control for Quadrotor Unmanned Aerial Vehicle: Theoretical and Experimental Verification

This paper studies the discrete-time adaptive fuzzy output feedback control for the altitude and attitude tracking problem of quadrotor unmanned aerial vehicle with input saturation. A discrete-time observer-based adaptive fuzzy command filtered backstepping control framework is proposed, which can not only solve the causal problem, but also design the discrete-time controller in the presence of immeasurable states. The adaptive control and fuzzy logic system are introduced to suppress the influence of model uncertainties and external disturbances, and the problem of input saturation is overcome by introducing an auxiliary system. It is proved that the tracking errors can converge to the sufficiently small neighborhood of the origin. Finally, the effectiveness of the control strategy are demonstrated by the simulation and experiment results respectively.