Most studies so far on trajectory tracking control of autonomous underwater vehicle (AUV) have assumed that the Euler angles are exactly known. However, the AUV inevitably suffers from external environmental disturbances which are driven by wind, density, and temperature gradients. The attitude transducers cannot derive accurate attitude information of the AUV. Additionally, the uncertain hydrodynamic parameters affect the stability of the system. Consequently, it is unknown whether tracking performance of the AUV can be guaranteed. In order to overcome these drawbacks, in this paper, a finite-time controller is developed by using the nonsingular fast terminal sliding mode control technique. A robust differentiator is proposed to estimate the external disturbances and uncertain parts. Simulations are performed to show that with the proposed control laws, the AUV converges to the desired trajectory even in the presence of external disturbances and system uncertainty.

中文翻译：

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未知参数和外部干扰的自主水下航行器轨迹跟踪控制

迄今为止，大多数关于自主水下航行器 (AUV) 轨迹跟踪控制的研究都假设欧拉角是完全已知的。然而，AUV不可避免地受到由风、密度和温度梯度驱动的外部环境干扰。姿态传感器无法获得 AUV 的准确姿态信息。此外，不确定的水动力参数会影响系统的稳定性。因此，AUV的跟踪性能是否能得到保证尚不得而知。为了克服这些缺点，本文利用非奇异快速终端滑模控制技术开发了一种有限时间控制器。提出了一种鲁棒微分器来估计外部干扰和不确定部分。