﻿ 水下机器人试航速度的类物理数值方法预报
«上一篇
 文章快速检索 高级检索

 哈尔滨工程大学学报  2020, Vol. 41 Issue (2): 194-198  DOI: 10.11990/jheu.201903073 0

### 引用本文

WU Lihong, ZHANG Aifeng, LI Yiping, et al. Prediction of autonomous underwater vehicle cruising velocity using a physics-based numerical method[J]. Journal of Harbin Engineering University, 2020, 41(2): 194-198. DOI: 10.11990/jheu.201903073.

### 文章历史

1. 大连海事大学 船舶与海洋工程学院, 辽宁 大连 116026;
2. 中国科学院沈阳自动化研究所 机器人学国家重点实验室, 辽宁 沈阳 110016

Prediction of autonomous underwater vehicle cruising velocity using a physics-based numerical method
WU Lihong 1,2, ZHANG Aifeng 1, LI Yiping 2, FENG Xisheng 2, WANG Shiwen 1
1. College of Ship Building and Ocean Engineering, Dalian Maritime University, Dalian 116026, China;
2. State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China
Abstract: The cruising velocity of an autonomous underwater vehicle (AUV) plays an important role in the evaluation of the thrust system performance and cruising endurance. This study proposed a physics-based numerical method for the prediction of the cruising velocity of the AUV. The full model of the AUV appended propeller and rudder was built. A multi-block hybrid dynamic grid method was used to mesh and re-mesh the domain. User-defined functions were programmed. Six degrees of freedom and unsteady Reynolds-averaged Navier-Stokes equations were solved to transfer forces and velocities between AUV and propeller. Thus, the free motion of the AUV pushed by the rotating propeller from stationary to uniform velocity was simulated. The numerical results showed that the rotating speed was 570 r/min at the cruising velocity of 1.5 m/s. The tip vortices were produced in self-propulsion motion. The strength of the tip vortices and propeller thrust decreased with the increase in the AUV velocity. The simulation investigated the unsteady flow field among the hull, propeller, and rudders in detail, which is helpful in conducting a precise maneuvering prediction of the AUV in complex environments.
Keywords: self-propulsion test    autonomous underwater vehicle(AUV)    dynamic mesh    physics-based simulation    screw propeller    cruising velocity    computational fluid dynamics    maneuverability

1 水下机器人自航模型建立

AUV为改进型REMUS AUV，L=1.7 m，D=0.191m[13]。具有椭球型艏、圆柱形平行中体和圆锥型艉。艉部有“十字”型舵翼以及一个MAU4-40，直径d=0.156 m的螺旋桨。AUV艏、舯和艉3段以及舵翼采用结构网格绘制，螺旋桨采用非结构网格离散。图 1为AUV带舵翼和螺旋桨的网格图。大地坐标系为oxyz, ox为AUV对称轴，向艏为正(向前)；oy垂直向上为正；oz指向右舷。

 Download: 图 1 带桨和舵的AUV网格模型 Fig. 1 Grid model of AUV appended propeller and rudders

 Download: 图 2 动网格分区 Fig. 2 Dynamic meshing zones

AUV自航推进过程数值模拟中，AUV和螺旋桨之间力和速度的传递可以采用用户自定义函数UDF(user defined function)进行编写，嵌入到程序中[14]：首先，AUV静止，螺旋桨以恒定转速旋转，产生推力，将此推力保存同时将推力传递给AUV；AUV读取螺旋桨推力，同时实时求解URANS(unsteady reynolds averaged navier-stokes)方程，获得AUV的阻力。AUV在推力和阻力的联合作用下，通过在6-DOF方程加载推力和实时阻力，求解载体的加速度，并采用龙格库塔积分获得AUV实时速度V；此速度传递给螺旋桨，使AUV拖曳螺旋桨以V航速运动；随着AUV航行，AUV的尾流场更新，影响螺旋桨的进流场，螺旋桨在新的进速和转速下产生新的推力，重新记录此推力并传递给AUV；AUV在阻力作用下，获得新的航速，如此重复，直到AUV的推力T与其航行阻力R接近平衡，速度曲线趋于稳定，加速度接近为零。或对比航速与多参考系坐标[15](multiple frames of reference, MFR)的定常自航点航速，两者误差在5%内，也认为达到自航点。记录此时的推力、阻力、速度历史数据，保存和分析。

2 水下机器人自航数值结果与分析 2.1 受力和速度

AUV以不同转速从静止自航推进，最终会趋于匀速状态。分别假定AUV以300、450、600 r/min 3种转速航行，每种转速自航一次，迭代步长为螺旋桨旋转1°对应的时间，每个外循环包含内循环20次，收敛精度为10-4。如图 3分别为转速为300、450和600 r/min的自航螺旋桨推力和AUV阻力的历史变化曲线。推力和阻力曲线在数值求解中有点振荡，这是动网格数值求解引起的不稳定现象。阻力部分振荡主要是由于载体低速巡航采用了和螺旋桨高速旋转的小时间步引起的。随着速度增加，推力减小，阻力增大，最终推力和阻力平衡，速度会趋于一个恒定的速度，这个速度即为该转速下的自航点。3种转速可得3次航速历史变化，如图 4所示，可得3个不同的自航点。转速越大，达到匀速的时间越短。600 r/min，需要约9 s, 可达到匀速1.55 m/s；450 r/min，需要约10.53 s, 可达到匀速1.15 m/s；300 r/min，需要约14.39 s, 可达到匀速0.74 m/s。同时，转速越大，起始加速度越大。

 Download: 图 3 不同转速下AUV自航阻力和推力变化 Fig. 3 The resistance (R) and Thrust (T) of AUV self-propulsion at different rotation speeds
 Download: 图 4 不同转速下AUV自航过程的航速变化 Fig. 4 Velocity history (V) in AUV self-propulsion at different rotation speeds (n)
2.2 数值验证

 Download: 图 5 AUV自航速度变化的试验和数值结果(n=300 r/min) Fig. 5 The velocity history from experimental and numerical results in AUV self-propulsion at n=300 r/min
 Download: 图 6 自航点对应的转速 Fig. 6 Approaching velocities vs. rotating speeds
2.3 流场分析

 Download: 图 7 AUV不同转速对应的自航点速度云图 Fig. 7 Velocity contours of AUV at different self-propulsion points with varying rotation speeds

 Download: 图 8 AUV自航对称面上不同时刻的速度云图(n=570 r/min) Fig. 8 Velocity contours of AUV self-propulsion on the symmetry plane at different times with n=570 r/min
 Download: 图 9 AUV自航对称面上不同时刻的压力云图(n=570 r/min) Fig. 9 Pressure contours of AUV self-propulsion at the symmetry plane at different times with n=570 r/min

3 结论

1) 水下机器人不同转速对应的最终巡航速度不同。300、450和600 r/min分别对应的巡航速度为0.74、1.15和1.55 m/s。AUV的巡航速度1.5 m/s对应的转速是570 r/min。

2) AUV自航稳定所需时间与AUV转速大小有关。转速越大，加速度越大，稳定需要时间越短。300、450和600 r/min稳定分别需要14.39、10.53和9 s。

3) 在螺旋桨转速变化较小的范围内，AUV的自航点速度和转速成正比关系。

4) AUV自航时，螺旋桨旋转运动曳出梢涡和根涡。梢涡强度随着AUV航速增加而降低，运动方向与AUV航行方向相反。根涡大小随AUV航速增加而增加，方向与AUV航行方向一致。

5) 螺旋桨推力的变化起源于其叶面和叶背压差变化。AUV以恒定转速自航，推力随速度增加而减小。

 [1] CHASE N, CARRICA P M. Submarine propeller computations and application to self-propulsion of DARPA SUBOFF[J]. Ocean engineering, 2013, 60: 68-80. DOI:10.1016/j.oceaneng.2012.12.029 (0) [2] PANKAJAKSHAN R, REMOTIGUE S, TAYLOR L, et al. Validation of control-surface induced submarine maneuvering simulations using UNCLE[C]//Proceedings of 24th Symposium on Naval Hydrodynamics. Fukuoka, Japan, 2002. (0) [3] POREMBA III J E. Hydrodynamics and maneuvering simulations of a non-body-of-revolution submarine[D]. PA, USA: The Pennsylvania State University, 2009. (0) [4] MOFIDI A, CARRICA P M. Simulations of Zigzag maneuvers for a container ship with direct moving rudder and propeller[J]. Computers & fluids, 2014, 96: 191-203. (0) [5] CARRICA P M, HOSSEINI H S, STERN F. CFD analysis of broaching for a model surface combatant with explicit simulation of moving rudders and rotating propellers[J]. Computers & fluids, 2012, 53: 117-132. (0) [6] 沈志荣.船桨舵相互作用的重叠网格技术数值方法研究[D].上海: 上海交通大学, 2014: 133-162. SHEN Zhirong. Development of overset grid technique for hull-propeller-rudder interactions[D]. Shanghai: Shanghai Jiao Tong University, 2014: 133-162. http://cdmd.cnki.com.cn/Article/CDMD-10248-1015807893.htm (0) [7] 于军, 聂义勇. 不可压缩流场多体运动问题的两种数值解法[J]. 计算力学学报, 2006, 23(5): 583-587. YU Jun, NIE Yiyong. Two numerical methods of multi-body movement in incompressible fluid[J]. Chinese journal of computational mechanics, 2006, 23(5): 583-587. DOI:10.3969/j.issn.1007-4708.2006.05.014 (0) [8] FURQUAN M, NAVROSE, MITTAL S. A fast mesh moving scheme for flow-induced vibrations of rigid bodies[J]. Computers & fluids, 2016, 141: 116-123. (0) [9] MURAYAMA M, TOGASHI F, NAKAHASHI K, et al. Simulation of aircraft response to control surface deflection using unstructured dynamic grids[C]//20th AIAA Applied Aerodynamics Conference. Louis, Missouri, 2002. (0) [10] WU Lihong, LI Yiping, SU Shaojuan, et al. Hydrodynamic analysis of AUV underwater docking with a cone-shaped dock under ocean currents[J]. Ocean engineering, 2014, 85: 110-126. DOI:10.1016/j.oceaneng.2014.04.022 (0) [11] ZHAN Jiemin, CAI Wenhao, HU Wenqing, et al. Numerical study on the six-DOF anchoring process of gravity anchor using a new mesh update strategy[J]. Marine structures, 2017, 52: 173-187. DOI:10.1016/j.marstruc.2016.12.007 (0) [12] 张来平, 邓小刚, 张涵信. 动网格生成技术及非定常计算方法进展综述[J]. 力学进展, 2010, 40(4): 424-447. ZHANG Laiping, DENG Xiaogang, ZHANG Hanxin. Reviews of moving grid generation techniques and numerical methods for unsteady flow[J]. Advances in mechanics, 2010, 40(4): 424-447. (0) [13] ALLEN B, AUSTIN T, FORRESTER N, et al. Autonomous docking demonstrations with enhanced REMUS technology[C]//OCEANS 2006. Boston, MA, USA, 2006. (0) [14] 吴利红, 李一平, 刘开周, 等.基于多块动态混合网格的AUV自航类物理数值模拟[J/OL].机器人: (2019-05-10)https://doi.org/10.13973/j.cnki.robot.180683.DOI:10.13973/j.cnki.robot.180683. WU Lihong, LI Yiping, LIU Kaizhou, et al. Physics-based numerical simulation of AUV self-propulsion using multi-block hybrid dynamic mesh method[J/OL]. Robot: (2019-05-10). https://doi.org/10.13973/j.cnki.robot.180683.DOI:10.13973/j.cnki.robot.180683. (0) [15] WEI Yingsan, WANG Yongsheng. Unsteady hydrodynamics of blade forces and acoustic responses of a model scaled submarine excited by propeller's thrust and side-forces[J]. Journal of sound and vibration, 2013, 332(8): 2038-2056. DOI:10.1016/j.jsv.2012.12.001 (0)