Vu Mai The, Le Tat-Hien, Thanh Ha Le Nhu Ngoc, Huynh Tuan-Tu, Van Mien, Hoang Quoc-Dong, Do Ton Duc
School of Intelligent Mechatronics Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747, Korea.
Department of Naval Architecture and Marine System Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City 700000, Vietnam.
Sensors (Basel). 2021 Jan 22;21(3):747. doi: 10.3390/s21030747.
Underwater vehicles (UVs) are subjected to various environmental disturbances due to ocean currents, propulsion systems, and un-modeled disturbances. In practice, it is very challenging to design a control system to maintain UVs stayed at the desired static position permanently under these conditions. Therefore, in this study, a nonlinear dynamics and robust positioning control of the over-actuated autonomous underwater vehicle (AUV) under the effects of ocean current and model uncertainties are presented. First, a motion equation of the over-actuated AUV under the effects of ocean current disturbances is established, and a trajectory generation of the over-actuated AUV heading angle is constructed based on the line of sight (LOS) algorithm. Second, a dynamic positioning (DP) control system based on motion control and an allocation control is proposed. For this, motion control of the over-actuated AUV based on the dynamic sliding mode control (DSMC) theory is adopted to improve the system robustness under the effects of the ocean current and model uncertainties. In addition, the stability of the system is proved based on Lyapunov criteria. Then, using the generalized forces generated from the motion control module, two different methods for optimal allocation control module: the least square (LS) method and quadratic programming (QP) method are developed to distribute a proper thrust to each thruster of the over-actuated AUV. Simulation studies are conducted to examine the effectiveness and robustness of the proposed DP controller. The results show that the proposed DP controller using the QP algorithm provides higher stability with smaller steady-state error and stronger robustness.
水下航行器（UVs）会受到洋流、推进系统以及未建模干扰等各种环境干扰的影响。在实际应用中，设计一个控制系统，使水下航行器在这些条件下永久保持在期望的静态位置是极具挑战性的。因此，在本研究中，提出了一种在洋流和模型不确定性影响下的过驱动自主水下航行器（AUV）的非线性动力学和鲁棒定位控制方法。首先，建立了在洋流干扰影响下过驱动AUV的运动方程，并基于视线（LOS）算法构建了过驱动AUV航向角的轨迹生成。其次，提出了一种基于运动控制和分配控制的动态定位（DP）控制系统。为此，采用基于动态滑模控制（DSMC）理论的过驱动AUV运动控制来提高系统在洋流和模型不确定性影响下的鲁棒性。此外，基于李雅普诺夫准则证明了系统的稳定性。然后，利用运动控制模块产生的广义力，开发了两种不同的最优分配控制模块方法：最小二乘法（LS）和二次规划（QP）方法，将适当的推力分配给过驱动AUV的每个推进器。进行了仿真研究，以检验所提出的DP控制器的有效性和鲁棒性。结果表明，采用QP算法的所提出的DP控制器具有更高的稳定性，稳态误差更小，鲁棒性更强。
