Unknown Input Observer-Based Fixed-Time Trajectory Tracking Control for QUAV with Actuator Saturation and Faults

The trajectory tracking control problem of a quadrotor unmanned aerial vehicle (QUAV) subject to external disturbances, inertia uncertainties, actuator faults, and input saturation is addressed in this paper. In contrast with previous works, herein refers rotor speed rather than thrust torque saturation. First, the system decoupled into translational rotational subsystems. Then, for both subsystems, two novel fixed-time unknown observers (UIO) based on disturbance filtering are developed estimate lumped rapidly precisely without awareness boundary disturbances. Furthermore, controllers subsystems proposed estimation values provided by UIO stabilize errors small region fixed time regardless initial values. theoretical analysis Lyapunov method presented demonstrate stability. Finally, simulation results show that effective. comparison carried out validate superiority observer its advantage can be summed up as: (1) upper bound or derivative not needed; (2) smoother observation precision higher due absence sign function; (3) mutant also estimated quickly precisely.