中文摘要：

针对舵桨联动式欠驱动水下机器人定深巡航任务,在运动学阶段设计关于垂向深度差的渐近视线制导角,从而将定深跟踪过程中垂向和俯仰的耦合控制转变为单一可控的俯仰控制,解决水下机器人垂向自由度上欠驱动特性.基于反步法技术在动力学阶段构建全系统李雅普诺夫函数,避免了运动学子系统与动力学子系统合成引起的复杂级联分析,提高了算法的艇载移植性.仿真结果表明：所设计的控制器对未知海流干扰具有一定的鲁棒性,能够确保欠驱动水下机器人准确跟踪期望的深度.

英文摘要：

For the fixed-depth cruising mission of an under-actuated underwater vehicle equipped with a stern propeller and rudders,an asymptotic line-of-sight guidance angle with respect to the depth error was designed in the kinematics layer,in order to transform coupling depth and pitch control into single pitch control,which solved the problem of the under-actuated configuration in heave.Subsequently,a full system Lyapunov function candidate via the backstepping technique was chosen in the dynamics layer,avoiding the complicated cascade analysis between kinematics and dynamics subsystems as well as improving the portability of the algorithm.Finally,numerical results show that the designed controller has a certain robustness against unknown ocean currents,and can guarantee the under-actuated underwater vehicle to accurately track the desired depth.