This paper presents a study of depth tracking controller design for a hybrid AUV in the presence of model uncertainty and propeller torque's effect. Firstly, the six degrees of freedom (6-DOF) nonlinear equations of motion, as well as the operating mechanisms and specific characteristics of the hybrid AUV, are described. Subsequently, the model for depth-plane is extracted by decoupling and linearizing the 6-DOF AUV model. Furthermore, a nonlinear disturbance observer (NDO) is constructed to deal with the linearization errors and uncertain components in the depth-plane model. A depth tracking controller is then designed based on the backstepping technique to guarantee the tracking error converges to an arbitrarily small neighborhood of zero. Besides, the robust stability of the proposed controller concerning the propeller torque's effect and the model uncertainty is analyzed. To ensure the objectivity and feasibility of the proposed method, the depth controller is applied to the 6-DOF model of AUV so that it maintains the coupling between roll, yaw, and pitch motion. Finally, the numerical simulation is carried out via MATLAB/SIMULINK to verify the controller's effectiveness, feasibility, and stability.

本文针对存在模型不确定性和螺旋桨转矩影响的混合AUV的深度跟踪控制器设计进行了研究。首先，描述了六自由度（6-DOF）非线性运动方程，以及混合AUV的工作机理和特定特性。随后，通过去耦和线性化6自由度AUV模型来提取深度平面模型。此外，构造了非线性干扰观测器（NDO）来处理深度平面模型中的线性化误差和不确定分量。然后基于反步技术设计深度跟踪控制器，以确保跟踪误差收敛到任意小的零邻域。此外，所提出的控制器关于螺旋桨转矩的鲁棒稳定性 效应和模型不确定性进行了分析。为了确保所提方法的客观性和可行性，将深度控制器应用于AUV的6自由度模型，以保持滚动，横摆和俯仰运动之间的耦合。最后，通过MATLAB / SIMULINK进行数值仿真，以验证控制器的有效性，可行性和稳定性。