Abstract:The water air amphibious tilting multi rotor unmanned ships was subject to complex and variable surface fluid forces during cross domain operations in a multi fish pond environment, resulting in significant fluctuations in the ship’s attitude and flight altitude. In order to improve the attitude stability of unmanned ships during surface takeoff, a model compensation based linear self disturbance rejection surface takeoff control method was proposed. Firstly, a detailed dynamic modeling of the multimodal unmanned ship was conducted. Secondly, considering the attitude changes during the takeoff process on the water surface, a real-time attitude estimation model and buoyancy estimation model was proposed based on unmanned ships. Then, a linear self disturbance rejection attitude and altitude controller based on model compensation was designed. Finally, a linear active disturbance rejection controller based on model compensation was designed. In the simulation experiment, compared with the PID algorithm, the proposed method reduced the roll convergence time by 66.7% and the roll fluctuation by 98.3%, reduced convergence time on the x-axis by 34%, reduced convergence time on altitude by 41.2% and the fluctuation on altitude by 80.0%. The simulation results verified the effectiveness and stability of the proposed method. In practical experiments, the unmanned ship achieved takeoff from the water surface with a flying altitude of 1.2m, fluctuations of roll less than three degrees, and a fluctuation of pitch and yaw less than two degrees. The experimental results showed that the proposed control algorithm effectively improved the stability and antiinterference ability of the water air amphibious tilting multi rotor unmanned ships during the water air cross domain process.
