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A robust controller using airspeed information is proposed for the attitude control of fixed-wing UAVs. Firstly, to reduce the adverse effects of the changeable airspeed, the tracking error model of the UAV is obtained by utilizing the measurement of airspeed. Then a robust controller is designed to achieve desired attitude tracking performance by restraining coupling effect, parameter uncertainties and external disturbances in the attitude dynamics. The robust controller consists of a nominal controller and a robust compensator. Finally, experimental results are provided to demonstrate the effectiveness of the control algorithm and verify the availability of the controller in the real world.

A fault detection and isolation scheme is proposed for a fixed-wing UAV swarm system in steady formation flight. Instead of using the state of each UAV directly, the relative states between UAVs are used to design the fault detection filter. The relative states are less affected by wind disturbance and model uncertainty when the states of different UAVs in the swarm are similar. Then a fault isolation method with a bank of observers are designed to isolate the fault UAV. Actual flight experiments with four fixed-wing UAVs are conducted outdoors. The experimental results show that the proposed scheme gives better fault diagnosis results in actual flight.