Research on Hydrodynamics Model Test for Deepsea Open-Framed Remotely Operated Vehicle

This paper presents the features of newly designed hydrodynamics test for the scaled model of 4500 m deepsea open-framed remotely operated vehicle （ROV）, which is being researched and developed by Shanghai Jiao Tong University. Accurate hydrodynamics coefficients measurement and spatial modeling of ROV are significant for the maneuverability and control algorithm. The scaled model of ROV was constructed by 1：1.6. Hydrodynamics coefficients were measured through VPMM and LAHPMM towing test. And dynamics model was derived as a set of equations, describing nonlinear and coupled 5-DOF spatial motions. Rotation control motion was simulated to verify spatial model proposed. Research and application of hydrodynamics coefficients are expected to enable ROV to overcome uncertainty and disturbances of deepsea environment, and accomplish some more challengeable and practical missions.

Study on Simulation of Remotely Operated Underwater Vehicle Spatial Motion

In order to analyze the spatial maneuverability of the remotely operated underwater vehicle(ROV),the 6-DOF motion mathematic model of the ROV was founded.Hydrodynamics were analyzed by using the Taylor series.The thrusters on the ROV were discussed.This paper considers three cases of motion simulation:vertical motion,rotational motion and Z-shape motion.A series of simulation experiments showed that the 6-DOF motion mathematic model was correct and reliable,and also fit with the scene simulation.

Multi-role Remotely Operated Marine Surface Vehicle

Development of man-packable,versatile marine surface vehicle with ability to rescue a drowning victim and also capable of carrying mission specific sensor is explored.Design thinking methodology is implemented by using existing equipment/platform with the addition of external attachment to make it a functional product.Iterative prototyping process with extensive testing to achieve user-centric solution.Individual prototypes and their possible sub-configurations with their integration and characteristics are studied and compared with numerical model,inferences obtained are utilised to improve for the next iteration.A novel hinge-clamp assembly enables this marine surface vehicle to operate in the event of an overturn,this phenomenon is further studied with the aid of a mathematical model(Pendulum in a fluid).This research project aims to demonstrate a multi-role unmanned surface vehicle.

欠驱动型ROV改进设计与纵倾优化

针对无人遥控潜水器(remotely operated vehicle,ROV)在高速航行时因受流场作用而导致纵倾幅值、纵倾角度变化较大的问题,提出通过搭配选择扩展底盘和尾翼结构参数的方法来实现欠驱动型ROV的零纵倾或微纵倾高速运动。基于格子玻尔兹曼方法(lattice Boltzmann method,LBM),通过壁面自适应细化算法,结合ROV的结构参数进行六自由度仿真实验,以模拟ROV的航行运动。对扩展底盘和尾翼高度不同的ROV分别进行数值分析,得到扩展底盘、尾翼的结构参数与ROV纵倾幅值、纵倾角度的关系。通过对航行表现相似的ROV的旋转力矩进行比较,确定了在相同扩展底盘条件下ROV的稳定性与尾翼高度的关系。开展了扩展底盘和尾翼结构优化正交实验,利用遗传算法对不同实验方案下ROV的纵倾数据进行了拟合处理。结合实际需求确定了扩展底盘和尾翼的高度,并通过实际测试验证了ROV纵倾优化设计方案的正确性。结果表明,合理搭配扩展底盘和尾翼的结构可有效减小欠驱动型ROV的纵倾幅值,从而实现ROV在无幅值补偿时的微纵倾航行运动。研究结果可为相关水下装置纵倾运动的改进提供参考。

故障检测与重构下基于AFTSMO的ROV三维航迹跟踪控制

针对传统的滑模观测器在缆控水下机器人(ROV)系统状态估计与故障重构过程中存在渐近收敛、无法及时准确重构故障信号的问题,提出一种基于自适应快速终端滑模观测器(adaptive fast terminal sliding mode observer)的故障检测和控制优化方法。建立带有推进器故障、未知外界干扰和模型参数不确定性等复合干扰的ROV系统故障模型;设计具有自适应特性的快速终端滑模控制器,保证所有的状态估计误差在有限时间内收敛;通过等效输出误差注入法对推进器引起的故障进行估计重构。采用Lyapunov稳定性理论验证控制系统的稳定性,仿真结果表明,所设计的故障检测方法能够快速检测和重构故障,保证ROV系统较高的跟踪精度,并通过实验验证了所提算法的有效性。

基于自适应S面算法的小型ROV艏向和深度运动控制研究

带缆遥控水下机器人(ROV)系统艏向与深度运动具有强非线性和运行环境不确定性等特点。针对ROV的运动特点,构建运动控制模型并进行化简,通过构建自适应S面控制法对艏向与深度进行控制,并利用Lyapunov的稳定性判据证明该控制法的稳定性,通过仿真验证了该控制法具有良好的稳定性和控制品质。同时,与S面控制法相比,自适应S面控制具有更好的动态性能与静态性能,调节速度快、稳定性强,能够准确控制ROV运动。

基于RBF神经网络补偿的ROV运动控制算法

针对作业型遥控水下航行器(ROV)在模型参数不确定和外部环境干扰下的运动控制问题,提出了一种基于径向基函数(RBF)神经网络的自适应双环滑模控制策略。首先,对于ROV外环位置控制采用改进趋近律的积分滑模控制方法,对于ROV内环速度控制采用指数趋近律的积分滑模控制方法;其次,为进一步改善滑模控制的抖振问题,引入双曲正切函数作为滑模切换项;然后,利用RBF神经网络控制技术对ROV模型的不确定参数和外部扰动进行估计与补偿;最后,利用李雅普诺夫稳定性理论证明了整个闭环系统的稳定性,并对作业型ROV的运动控制进行了数值仿真。仿真结果验证了所设计的控制器可以实现ROV航行的精确控制,并能够有效抑制模型不确定参数和外部扰动对ROV运动的影响。

改进型自抗扰在ROV位姿控制中的应用

为提高水下机器人(ROV)在水域环境中的位姿控制能力,结合传统自抗扰控制(Active Disturbance Rejection Control,ADRC)策略中fal函数在分段处过渡不够平滑的特点,提出一种新型非线性函数,用以改进传统fal函数。利用双曲正切函数在原点附近单调递增且连续光滑的特征,通过多项式拟合的方法构建出非线性函数sfal函数,然后使用李雅普诺夫方法对sfal函数进行稳定性分析,基于sfal函数给出扩张状态观测器的一般形式,并由此设计改进的ADRC控制器,通过对控制对象ROV搭建数学模型,利用Matlab/Simulink对系统的输出进行仿真与数值分析。最后,在ROV平台上进行对比实验,实验结果表明,改进型自抗扰控制能够有效抑制系统响应的超调量,并提升ROV位姿状态的抗扰能力。

深水ROV工具篮子结构设计载荷与屈服强度分析

水下机器人ROV(remote operated vehicle)工具篮子用于在陆地和深海中储存ROV安装工具,除方便ROV进行操作外,同时给ROV工具提供保护,能够很好地适应深远海环境,是水下生产系统的重要组成部件。其深海安装作业风险高、要求严,研究其安装全过程工况的强度性能对确保整个水下生产系统平稳运行具有重要作用。针对南海陵水气田使用的ROV工具篮子深海多种典型工况,计算得到设计载荷,然后对其进行有限元建模分析,计算不同载荷工况下的应力响应,对结构的屈服强度进行校核,以确保整体结构强度满足安全规范要求。计算结果表明:ROV工具篮子在多种提升工况、冲击工况以及运输工况下结构屈服强度均满足规范要求,在此基础上,指导现场使用的ROV工具篮子设计,整个海上安装及水下运行安全可靠。研究成果可为ROV工具篮子以及类似水下结构物的结构设计和深海安装提供理论基础和技术参考。

基于改进混合运动麻雀搜索算法的水电站ROV路径规划

水下遥控机器人(ROV)路径规划是水电站水下巡检作业的关键。针对电站水库下复杂环境及现有路径规划算法存在规划时间长、算法稳定性差、易陷入局部最优及生成路径不平滑等问题,提出一种基于改进混合运动麻雀搜索算法的水电站ROV路径规划方法。首先,引入佳点集改进麻雀种群初始化方法,提高了种群多样性;其次,提出混合运动策略优化麻雀群体位置更新方式,提高了算法收敛精度及稳定性;然后,结合工程实际问题,考虑水库下水流速度大、强磁场、障碍物以及投入成本等因素,建立了包含时间成本、路径威胁、水流扰动和偏置函数的多元目标函数;最后,采用三次B样条插值得到最优光滑路径。仿真结果表明,相较于其他路径规划算法,所提方法在计算精度、收敛速度和稳定性方面表现更好,适用于水电站水下巡检任务。

ROV仿真平台技术研究

遥控有缆机器人(ROV)在海洋资源开发、管道/线缆铺设中发挥着重要作用,但其海洋实验成本高昂,且要求操作员具有丰富的操作经验。为辅助培训ROV操作员并提高ROV实验效率,文章设计了一种硬件在环、具有三维可视化功能的仿真平台,其既可直接与现场应用的ROV控制系统连接进行软件测试与功能验证,又可以直接用于操作员培训。该平台通过ROV物理模型和ROV数学模型等模拟实物ROV,并在虚拟视景中构建ROV运动场景、在虚拟环境中模拟ROV作业。基于ROV数学模型,其计算ROV运动数据并将运动数据信息传递到ROV三维模型进行动态显示,同时将实时运动信息反馈给ROV控制系统。结合水池实验中ROV速度随推进器转速变化的实验数据,文章对比分析了实验数据与仿真平台计算数据。结果表明,该仿真平台能有效代替实物实验并辅助ROV操作员培训,可大大节省培训与实验成本,提升ROV操作员培训效率。

基于迁移学习的ROV水下建筑物缺陷识别方法

水下建筑物缺陷检测是保障电厂长期安全稳定运行的关键。为解决检测任务繁重危险,提高检测效率,降低人工检测成本,提出一种基于水下机器人(ROV)的水下建筑物缺陷识别方法。针对水下成像环境复杂、噪声大、检测流程冗长等问题,设计了一种基于迁移学习的图像识别模型。首先,通过图像数据处理算法,提高水下缺陷图像质量,并对图像进行二值化处理,突出缺陷特征;然后通过卷积核提取图像中的突出特征,引入注意力机制对特征重要程度进行计算分配,提高模型特征提取效率;最后在训练过程中引入迁移学习,解决实际缺陷数据不足的问题,提高模型训练效率。结果表明,设计的迁移学习图像识别模型在标准数据集和实测缺陷数据集上准确率达到90%~95%,且迭代次数在30代以内,能够精确高效识别水下建筑物缺陷特征。

ROV在海上风电水下检测的应用

近年来,我国海上风电快速发展。风电机组和海上升压站的桩基础、海缆等水下资产对海上风电场的安全稳定运行至关重要,一旦出现问题将会导致严重的发电损失,甚至可能影响安全。缆控水下机器人(ROV)在海洋石油工程具有广泛的应用,也逐步开始在海上风电的水下检测中应用。文章针对海上风电水下桩基础、海缆等水下资产在生产运维过程中的典型问题、检测需求和ROV目前应用的检测技术和检测设备进行了分析、总结,对目前应用中存在的问题和未来发展进行讨论,为ROV在海上风电场水下检测中的应用提供参考。

基于扩张观测器的ROV固定时间轨迹控制

针对六自由度遥控无人潜水器(ROV)的轨迹规划控制问题,提出基于固定时间扩张观测器的非奇异积分终端滑模控制方法。建立考虑系统模型不确定性及外界扰动的ROV六自由度数学模型,采用一种基于固定时间收敛的扩张状态观测器,实现对系统集总干扰的准确估计以补偿控制系统的控制律;设计固定时间非奇异积分终端滑模控制器以保证ROV系统的轨迹跟踪性能,并基于Lyapunov稳定性理论证明系统的固定时间稳定性。仿真结果表明:与以往控制方法相比,文章所提方法提高了控制系统的性能及精度,可保证水下机器人在不同初始状态下均能在固定时间内达到轨迹跟踪的效果。

OBLIQUE TOWING TEST AND MANEUVER SIMULATION AT LOW SPEED AND LARGE DRIFT ANGLE FOR DEEP SEA OPEN-FRAMED REMOTELY OPERATED VEHICLE

This article presents the newly designed oblique towing test in the horizontal plane for the scaled model of 4 500 m deep sea open-framed Remotely Operated Vehicle （ROV）,which is being researched and developed by Shanghai Jiao Tong University.Accurate hydrodynamics coefficients measurement is significant for the maneuverability and control system design.The scaled model of ROV was constructed by 1：1.6.Hydrodynamics tests of large drift angle were conducted through Large Amplitude Horizontal Planar Motion Mechanism （LAHPMM） under low speed.Multiple regression method is adopted to process the test data and obtain the related hydrodynamic coefficients.Simulations were designed for the horizontal plane motion of large drift angle to verify the coefficients calculated.And the results show that the data can satisfy with the design requirements of the ROV developed.

Automatic analysis of deep-water remotely operated vehicle footage for estimation of Norway lobster abundance

Underwater imaging is being used increasingly by marine biologists as a means to assess the abundance of marine resources and their biodiversity. Previously, we developed the first automatic approach for estimating the abundance of Norway lobsters and counting their burrows in video sequences captured using a monochrome camera mounted on trawling gear. In this paper, an alternative framework is proposed and tested using deep-water video sequences acquired via a remotely operated vehicle. The proposed framework consists of four modules:(1) preprocessing,(2) object detection and classification,(3) object-tracking, and(4) quantification. Encouraging results were obtained from available test videos for the automatic video-based abundance estimation in comparison with manual counts by human experts(ground truth). For the available test set, the proposed system achieved 100%precision and recall for lobster counting, and around 83% precision and recall for burrow detection.

Design of motion control of dam safety inspection underwater vehicle

Plenty of dams in China are in danger while there are few effective methods for underwater dam inspections of hidden problems such as conduits,cracks and inanitions.The dam safety inspection remotely operated vehicle(DSIROV) is designed to solve these problems which can be equipped with many advanced sensors such as acoustical,optical and electrical sensors for underwater dam inspection.A least-square parameter estimation method is utilized to estimate the hydrodynamic coefficients of DSIROV,and a four degree-of-freedom(DOF) simulation system is constructed.The architecture of DSIROV's motion control system is introduced,which includes hardware and software structures.The hardware based on PC104 BUS,uses AMD ELAN520 as the controller's embedded CPU and all control modules work in VxWorks real-time operating system.Information flow of the motion system of DSIROV,automatic control of dam scanning and dead-reckoning algorithm for navigation are also discussed.The reliability of DSIROV's control system can be verified and the control system can fulfill the motion control mission because embankment checking can be demonstrated by the lake trials.

Using Unmanned Underwater Vehicles as Research Platforms in Coastal Ocean Studies

The advantages of using unmanned underwater vehicles in coastal ocean studies are emphasized. Two types of representative vehicles, remotely operated vehicle (ROV) and autonomous underwater vehicle (AUV) from University of South Florida, are discussed. Two individual modular sensor packages designed and tested for these platforms and field measurement results are also presented. The bottom classification and albedo package, BCAP, provides fast and accurate estimates of bottom albedos, along with other parameters such as in-water remote sensing reflectance. The real-time ocean bottom optical topographer, ROBOT, reveals high-resolution 3-dimentional bottom topography for target identification. Field data and results from recent Coastal Benthic Optical Properties field campaign, 1999 and 2000, are presented. Advantages and limitations of these vehicles and applications of modular sensor packages are compared and discussed.

基于改进YOLOv5s的桥墩缺陷检测ROV设计应用

针对桥墩附近乱流现象严重和桥墩表面光滑难以吸附的问题,采用浮游加抱臂爬行方式,利用复合控制技术设计了一款桥墩缺陷检测ROV。首先,ROV本体结构采用8矢量推进器布局方案,实现了机器人浮游状态全向运动,提高了ROV抗扰能力;其次,抱臂夹持机构采用绳传动方式,以机械简单联动为ROV爬行状态下的稳定检测提供了可靠平台;最后,采用基于注意力机制改进的YOLOv5s网络识别桥墩缺陷,通过引入ASPP、IAAM等结构,提升了缺陷检测的实时性与精度。真实水域试验结果表明,所设计的ROV具有很好的适用性和有效性,在复杂水域环境下取得了较好的桥墩缺陷检测应用效果,可代替潜水员完成桥墩缺陷采集工作。

Remote Operation SW for USV: Part II. Simulation Development

For contingencies occurring in a complex marine environment, Unmanned Surface Vehicle (USV) has to recognize the situation and decide behaviors,?and?plan the following actions through the Integrated Mission Planning Process. Therefore, researches are actively being carried out about it. However, since it is difficult to test the actual USV with the mission planning process, it is necessary to develop a virtual experimental environment based on Modeling?&?Simulation (M&S). In this study, we developed an integrated simulation environment capable of simulating and analyzing the overall mission of USV. In Part?I, we modelled the USV Integrated Mission Planning Process and in Part?II, we developed an experimental framework and interface for loading them. In addition, we verified the suitability of this model through scenarios and defined the Mission of Effectiveness (MOE) concept for USV mission analysis.