Autonomous landing for unmanned seaplanes based on active disturbance rejection control

Autonomous landing for unmanned seaplanes safely in severe sea states has been a great challenge for decades. A new autonomous landing system of an unmanned seaplane based on active disturbance rejection control (ADRC) is presented in this paper. Firstly, different landing phases of the unmanned seaplane are analyzed. Then according to the characteristics in the different phases, the autonomous landing system consists of a velocity control subsystem and an attitude control subsystem. The velocity control subsystem consists of a velocity ADRC controller and a throttle switch module, while the attitude control subsystem consists of a pitch angle ADRC controller, an altitude PID controller, a pitch angle switch module and a T-S fuzzy reasoning module. Simulations are performed in calm water and irregular wave. The simulations results show that the proposed control system is capable of making the unmanned seaplane land successfully with satisfactory performance.