Fixed-Time Attitude Control for Autonomous Underwater Helicopter With Attitude Regulator

We introduce a new attitude regulator for the attitude-regulating autonomous underwater helicopter (ARAUH), utilizing buoyancy blocks and a movable mass slider to adjust the ARAUH's attitude. Initially, the ARAUH's mechanical structure and dynamic model are described, and the attitude regulator structure is designed. Furthermore, considering the uncertainty and nonlinearity of the ARAUH model, an adaptive fixed-time attitude controller is designed to swiftly stabilize the attitude. Using simulation, the stability condition of control is determined, and the effectiveness, robustness, and feasibility of the controller are validated through experimentation in real-world scenarios. Ultimately, the experimental findings demonstrate that the attitude regulator can alter the pitch and roll angles of the robot between <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\bf{-90^{\boldsymbol{\circ}}}$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\bf{90^{\boldsymbol{\circ}}}$</tex-math></inline-formula>, and the attitude controller has significantly superior performance in various motions, with a specific reference value for the self-attitude adjustment of autonomous underwater vehicles.