Vision-based tracking with projective mapping for parameter identification of remotely operated vehicles

Parameter identification of a remotely operated vehicle (ROV) is often based on the dynamic responses collected by its onboard sensors. However, for commercial ROVs, the required data for identification may not be available due to the absence of suitable sensors or limitations in accessing onboard sensor data. Therefore, this study proposes a vision-based tracking system to measure the dynamic response of an ROV. The tracking system is independent of the ROV, and is able to localize an ROV to a high degree of precision by means of projective mapping. The validity of the proposed tracking system is demonstrated through identification of a commercial ROV. A simplified nonlinear ROV dynamic model with six degrees of freedom (DOF) is used for identification. Uncoupled motions, including surge, sway, and yaw, are obtained from the ROV dynamic model, and the corresponding experiments are carried out for each DOF. Hydrodynamic parameters are then estimated with numerical optimizations by comparing the measured ROV responses with the output of the mathematical model. The experimental results show that the vision-based tracking system can accurately measure the transient and steady-state responses of an ROV. Additionally, the simulations of the ROV dynamic model, with the optimal parameter estimates, give results in agreement with the measured data.     

CTD传感器在ROV系统中的扩展及其应用

CTD可以获取海洋物理学环境参数,为海洋物理学的研究提供重要的基础性数据,而ROV作为重要的海洋探测工具和科学研究平台已经在世界各国主要的海洋研究机构中得到广泛应用。根据＂海狮号＂ROV系统的体系结构特点,对其通讯、控制和电源等接口进行扩展,实现了CTD传感器在ROV上的应用,并在海洋区域地质调查的ROV测站作业时进行了CTD数据的采集,数据质量满足了海洋区域地质调查的要求。     

观察型水下机器人ROV系统配置研究

在简述无人遥控潜行器(ROV)系统构成的基础上,就观察型ROV的推进系统、成像系统、应用环境以及风险分析等方面进行深入探讨,提出了在我国海域环境下,有关水下机器人系统配置以及实际应用等方面的建议。     

Modeling, identification, and analysis of limit-cycling pitch and heave dynamics in an ROV

The topic of this paper is the modeling, parameter identification, and analysis of the heave and pitch dynamics in a remote operated vehicle (ROV). The work presented here is motivated by an unusual dynamic behavior experienced on the Gaymarine Pluto-Gigas ROV: if the depth is regulated using a proportional controller, the ROV exhibits permanent oscillations at high forward speed. The purpose of this paper is to gain insight into ROV dynamics, so as to explain the reason for the oscillations. To this end, a dynamic gray-box model is developed and its uncertain parameters are identified from real data. The analysis of such a model shows that the nonlinear dynamics of the ROV contains a limit cycle. This discovery explains the observed oscillatory behavior. An interesting aspect of this limit-cycling behavior is that it is not due (as usual) to saturation effects of the actuators, but is intrinsic in the ROV dynamics.     

Design of a high performance variable structure position control ofROVs

An adaptive control scheme for dynamic positioning (DP) of remotely operated underwater vehicles (ROV) is proposed based on a recently developed output feedback variable structure control (VSC) algorithm named VS-MRAC. Only position measurement is required. Precise modeling of the ROV is not needed and unmodeled perturbations can be effectively rejected. A simple method for discretizing the original continuous-time VS-MRAC is proposed based on dead-beat response. Other important practical implementation issues are considered. The performance is evaluated by simulation with a realistic ROV model and by full-scale experimental pool tests with an actual ROV     

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.     

堆内构件检测ROV设计与实现

根据核堆内构件检测的需求,设计研发了一款超小型无人遥控潜水器(ROV)。从总体、结构、电控等方面,论述了该潜水器面临的问题和设计特点。着重论述了核环境下系统器件材料的耐辐照要求,并对关键器件进行了耐辐照性试验,结果表明所选器件能够满足辐照环境下的应用要求。最后给出了系统的水池实验结果,证明该系统具有良好的操纵性和稳定性。     

On the motions of the underwater remotely operated vehicle with the umbilical cable effect

In this paper, a hydrodynamic model is developed to simulate the six degrees of freedom motions of the underwater remotely operated vehicle (ROV) including the umbilical cable effect. The corresponding hydrodynamic forces on the underwater vehicle are obtained by the planar motion mechanism test technique. With the relevant hydrodynamic coefficients, the 4th-order Runge–Kutta numerical method is then adopted to solve the equations of motions of the ROV and the configuration of the umbilical cable. The multi-step shooting method is also suggested to solve the two-end boundary-value problem on the umbilical cable with respect to a set of first-order ordinary differential equation system. All operation simulations for the ROV including forward moving, ascending, descending, sideward moving and turning motions can be analyzed, either with or without umbilical cable effect. The current effect is also taken into consideration. The present results reveal that the umbilical cable indeed significantly affects the motion of the ROV and should not be neglected in the simulation.     

用于近海海洋环境检测的轻型机器人

介绍一种新研制的用于近海海洋环境检测的轻型机器人,该机器人由智能检测控制台、水下检测器和控制电缆三部分构成;水下检测器由6个独立密封舱室和尾翼组成,具有一个主推进器和两个侧向推进器。特点是采用了潜艇式ROV结构,大幅降低了成本,适度增大了负载,可以满足一般工程检测的需要。通过在控制台上发出指令,可控制ROV完成前进、后退,上浮、下沉、左右转弯等动作;可以实现一定流速下的动力悬停,可以使ROV保持一定的倾角,以配合实现检测作业。该水下机器人可以检测腐蚀电位、温度、深度等最多16个参数,设计深度为40m。     

Underice Operation of SJT-5 ROV

- The authors have used a low-cost ROV of observation type for underice surveying of the Nen-Jiang Cross-river oil pipe line in the Da Qing oil field. The operation method, process and the safety measures for severe cold areas are presented. The fruitful tries and experience may be useful to ROV operators in severe cold areas.     

Robust ROV path following considering disturbance and measurement error using data fusion

ROV accurate path following is challenging due to system unmodeled dynamics, disturbances and navigation sensors error. The model uncertainty and disturbances are commonly treated using robust methods such as the sliding mode controller where by incorporating an integral action in the zero tracking error is also guaranteed. Practically, the ROV position data is often computed using low cost inertial measurement unit (IMU) with outputs contaminated with bias and noise. Failure of mission is an immediate consequence of employing such biased sensors. However, the problem can be circumvented using the concept of redundant measurements and data fusion. In this respect, a set of 12 measurements from IMU, magnetometer and Doppler velocity log (DVL) are employed where the last two are aided sensors. The set up is shown to be capable of providing ROV path following with zero (in average) steady state tracking error irrespective of its dynamic parameters, environmental disturbances and erroneous data; as if it enjoys the exact values of the position of the ROV. It means that the combined DVL and magnetometer are sufficient for filtering the IMU biased measurements. Various simulations conducted confirm the results.     

ROV在我国海洋区域地质调查中的应用

远程遥控水下机器人系统是一种先进的海洋综合调查设备,能够实现海底长时间、高精度的定点取样作业及其他精细调查,在海洋区域地质调查中利用ROV开展高精度海底取样及其环境调查方面具有其他调查设备无法比拟的优越性。ROV具有功能多、综合作业能力强、安全可靠和实时遥控等优点。目前国内利用ROV进行海洋区域地质调查还处于起步阶段,随着ROV在海洋调查中的应用技术不断成熟和完善,利用ROV进行海洋区域地质调查将大大提高海洋区域地质调查的装备水平和调查精度,具有广阔的应用前景。以＂海狮号＂ROV系统为例,介绍其在我国海洋区域地质调查中的典型应用。     

开架式水下机器人运动的模糊非线性PD控制方法

由于水下机器人系统的非线性动力学特性和工作环境的复杂性和不确定性,如何更好地设计水下机器人作业时的运动控制器一直是其实用化过程中没能得到很好解决的问题。结合模糊逻辑和S面控制,利用T—S推理结构,设计了一种兼具局部和全局调整功能的模糊非线性PD(m)控制器,仿真结果表明,其控制效果要优于采用单一控制参数的S面控制器。     

深海遥控潜水器多体系统非线性耦合动力特性模拟

建立带缆遥控潜水器(TROV)系统空间运动模型,探讨支持船-吊缆-中际站-脐带缆-潜水器多体之间的强非线性耦合运动机理。潜器的运动考虑为六自由度,缆索分段的三维动态方程中采用了"凝集参数"模型与平均切向量非线性流体动力载荷处理技术,通过计算非均匀缆索的动张力和瞬态构型,预报导致脐带缆保护层及其内部光电传输芯线结构破坏的巨大瞬间突变载荷,对避免谐振,延长缆索寿命和最大限度地扩大ROV系统安全操作的范围,确保潜水器安全入坞和回收,节约试验费,避免作业事故都具有重要意义。     

TROJAN: Remotely operated vehicle

Following success in remotely operated vehicle (ROV) designs such as MMIM, IZE, SOLO, ORVIL, CIRRUS, PIC, and OBSERVER, Slingsby Engineering Limited (SEL) has now developed its technology to build and prove a new ROV, TROJAN. TROJAN is a dedicated subsea support vehicle, which results from extensive market research being applied to a base of 15 years in the underwater technology market. SEL has been at the forefront of the evolution of this market from early manned submersible days, followed by atmospheric diving systems to ROV's. The TROJAN ROV is conceived as a subsea workhorse offering a new dimension to subsea support operations. TROJAN benefits by incorporation of proven technology developed by SEL in recent years on SOLO, PIC, and CIRRUS projects. Using standard components, TROJAN's high reliability and efficient performance offer a versatile and cost-effective work system.     

基于长基线系统深海采矿ROV精确定位

对于深海采矿集矿机ROV的定位,采用传统的长基线水声定位系统通常存在较大误差。对此提出了一种新的算法模型,首先通过比较集矿机测量位置与前一次修正位置的几何关系,对当前集矿机的位置进行修正,然后利用新的集矿机位置修正声速的数值,并得出重新修正后的集矿机测量位置。这样反复的多重迭代使得在某一时刻集矿机ROV的测量位置逐步趋近其理想位置,实现长基线系统的水声精确的三维立体定位。通过数值仿真分析,结果显示与传统的长基线水声定位方法相比,通过该方法获得的集矿机行驶轨迹能更好地趋近其理想行驶曲线,表明该算法的有效性。     

东方1-1海管悬跨分布特征及治理效果分析

海底管道对海上油气田安全生产有着非常重要的作用,对东方1-1海管进行了连续6年的无人有缆遥控水下机器人(remote operatedvehicle,ROV)调查,根据调查数据,分析了海管悬跨的分布特征以及变化情况,按海管悬跨严重程度进行了风险等级分区。结果表明在受水动力影响最大的深水平坦区海管悬跨分布密集,并有逐年加剧趋势,安全风险较大。并对悬跨形成机理和极限悬跨长度进行了分析和阐述。介绍了沙袋支撑和局部抛石填埋悬跨治理方法的原理和优缺点,对比分析了治理效果情况,认为局部抛石治理方法效果优于沙袋治理。     

Redundancy resolution for underwater mobile manipulators

A new fault-tolerant redundancy resolution scheme is presented that allows a single six degree of freedom (DOF) command to be distributed over a small remotely operated underwater vehicle–manipulator (ROVM) system. ROVM systems are composed of a remotely operated underwater vehicle (ROV) and serial manipulator. The combined system is often kinematically redundant for the six-DOF end-effector command, and such a ROVM system admits an infinite number of joint-space solutions for a commanded end-effector state. In the current work, the primary objective is to follow the desired end-effector velocities commanded by a human pilot. The primary objective is realized using the right Moore–Penrose pseudoinverse solution that minimizes the two-norm of the collective joint velocities. Secondary objectives considered are: avoiding manipulator joint limits, avoiding singularities and high joint velocities, keeping the end-effector in sight of the on-board camera, minimizing the ROV motion, and minimizing the drag-forces on the ROV. Each criterion is defined within the framework of the gradient projection method (GPM). The hierarchy for the secondary tasks is established by a low-level artificial pilot that determines a weighting factor for each criterion based on if–then-type fuzzy rules that reflect an expert human pilot's knowledge. The resulting weight schedule yields a self-motion (null-space motion) that emulates how a skilled operator would utilize the redundancy of the ROVM to achieve the secondary objectives. In addition, the proposed method has a fault-tolerant property that enforces joint-velocity limits and also redistributes the end-effector velocity command in the case of faulty joints. To demonstrate the efficacy of the proposed scheme, a numerical simulation case study is performed. The results illustrate that complex spatial end-effector manoeuvres that are otherwise not possible with a stationary ROV can be accomplished in real-time via the coordination of the ROV and the manipulator. The on-line nature of the proposed scheme makes it suitable for remote systems where the desired end-effector state is not known a priori.     

遥控水下机器人脐带缆收放绞车设计及牵引力分析

脐带缆收放技术是有缆遥控水下机器人的一项关键技术,该技术直接影响水下机器人载体的收放及作业过程中脐带缆的安全。针对目前水下机器人收放系统中脐带缆收放技术的特点,给出了一种具有自动排缆、低张力缠绕、能够提供大牵引力和安全制动功能的紧凑新式脐带缆绞车方案,并对牵引绞车与储藏绞车之间脐带缆张力与牵引绞车的牵引力进行了理论分析,给出了二者之间的关系函数。     

海底管道在位状态调查实践

根据调查设备搭载器的不同,将海底管道在位状态调查方法归为船载、自治水下机器人搭载(AUV 搭载)和无人遥控潜水器搭载(ROV搭载)三类;在浅水段采用船载调查,在深水段采用AUV搭载调查,在此基础上进行重点关注区域筛选,开展ROV调查,最后进行整体评价和分析对比,这种^“(船载/AUV)+ROV^”组合模式很好地实现了多种调查方法的优势互补。实际上,采用AUV搭载进行海底管道在位状态调查在国内业界尚属首次。调查所取得的管道位置、埋深、周边障碍物的分布以及管道人工处理情况等成果,为后期开展管道维护工作提供了重要的基础数据。此次成功实践可为以后从浅水到深水的管道在位状态调查提供经验和借鉴。