基于干扰观测器的AUV深度自适应终端滑模控制

针对欠驱动自治水下机器人（autonomous underwater vehicle，AUV）在外部干扰和系统内部扰动下深度难以控制的问题，提出基于非线性干扰观测器（nonlinear disturbance observer，NDO）的自适应终端滑模控制方法。首先建立欠驱动AUV在垂直面上的状态方程并对其简化，其次根据简化后的系统状态方程构建NDO对外部干扰进行观测，再结合反步法设计出自适应终端滑模控制器；最后通过李雅普诺夫稳定性理论证明控制系统的稳定性。结果表明：欠驱动AUV最大跟踪误差为0.137 5 m，峰值时间为2.1 s，证明了所设计的控制器能够实现深度控制，降低抖振，具有较强的鲁棒性。

Adaptive terminal sliding mode control of autonomous underwater vehicle(AUV)depth based on a disturbance observer

The depth of an underactuated autonomous underwater vehicle (AUV) is difficult to control under external and internal disturbances. In an attempt to solve this problem, an adaptive terminal sliding control method based on a nonlinear disturbance observer (NDO) is proposed in this work. The state equation for the underactuated AUV in the vertical plane is first established and simplified. Secondly, based on the simplified state equation, the NDO to observe the external interference is constructed, and then the self-adaptive terminal sliding mode controller is designed by using a backstepping method. Finally, the stability of the control system is shown to be stable by using Lyapunov stability theory. The simulation results show that the maximum tracking error of the underactuated AUV is 0.137 5 m and the peak time is 2.1 s. These results show that the controller can achieve depth control with low chattering and strong robustness.