深海ROV铠缆系统动态特性与半主动升沉补偿技术研究 | |
Alternative Title | Research on Dynamic Characteristics of the Umbilical Cable System and Semi-active Heave Compensation Technology for Deep-sea ROVs |
全伟才1,2 | |
Department | 水下机器人研究室 |
Thesis Advisor | 张艾群 ; 张竺英 |
Classification | TP242 |
Keyword | 深海rov 铠缆 被动升沉补偿 半主动升沉补偿 相似模型实验 |
Call Number | TP242/Q93/2014 |
Pages | 176页 |
Degree Discipline | 机械电子工程 |
Degree Name | 博士 |
2014-05-23 | |
Degree Grantor | 中国科学院沈阳自动化研究所 |
Place of Conferral | 沈阳 |
Abstract | 本文结合深海ROV在高海况下安全作业和收放的实际需求，以深海ROV水下铠缆系统为研究对象，分别从理论建模和模型实验两方面深入研究了深海ROV铠缆系统的动态特性与半主动升沉补偿技术。主要研究内容可概述为如下几个方面： (1) 对三维非线性铠缆的有限元建模进行深入的研究。基于几何精确梁的Reissner-Timoshenko假设，根据虚功原理得出水下铠缆动力学方程的弱形式模型。采用几何精确梁有限元列式的完全Lagrangian列式，即未知变量为梁中线位移与梁截面转角。利用Frechet导数推导完全Lagrangian列式的线性化过程，并利用等参插值思想采用二节点等参插值单元对水下铠缆模型进行离散，对单元范围内的总虚功残值项离散得到残余节点力，对单元范围内的总虚功线性增量项离散得到质量矩阵、切向刚度矩阵及载荷刚度矩阵。将单元节点力组装后得到总体节点力矢量，单元矩阵逐个组装后得到总体质量矩阵和刚度矩阵，从而得出水下铠缆的三维完全几何非线性的有限单元方程，并确定求解所需的上端运动学边界条件和下端动力学边界条件。 (2) 研究三维非线性铠缆有限元模型的数值解法及有效性验证。采用FORTARN语言编制有限元分析程序QCAB，为便于对比，数值算法分别采用标准Newmark算法与广义 算法。根据水下铠缆有限元模型推导相适应的标准Newmark算法与广义 算法形式，结合Newton-Raphson迭代算法，以求解质量矩阵和刚度矩阵时变的非线性动态问题。给出有限元程序的总体布局、系数矩阵及节点力的计算模块。通过柔性缆索的异面弯曲、螺旋成型和三维旋转算例验证有限元程序求解非线性静态平衡问题和动态问题的有效性。最后采用深海ROV系统ROPOS在大洋1730米深处的实测数据进行验证，对比说明标准Newmark算法与广义 算法的数值计算性能，证明铠缆有限元模型、隐式时间积分算法和有限元程序的正确性。 (3) 对深海ROV铠缆系统的动态特性进行详细的分析。首先进行铠缆系统的静态分析，包括无母船升沉无海流情形与无母船升沉有恒定海流两类情形，分析结果作为动态分析的初始条件。接着进行铠缆系统的动态分析，具体包括两类，即仅有母船升沉激励和母船升沉与海流联合激励。在第一类动态分析中分别研究在理想正弦升沉和实际测量升沉激励下的水下铠缆系统的动态响应与共振现象，得出3500米潜深左右为该深海铠缆系统的共振区域。在第二类动态分析中研究在升沉与海流联合激励时铠缆系统空间动态构型及铠缆两端运动与张力变化情况，并着重分析联合激励时的共振现象，得出与第一类动态分析相同的结论，即水下3500米潜深左右的深度范围为该铠缆系统的共振区域。 (4) 研究半主动升沉补偿系统及其模型的设计及系统性能分析。根据半主动升沉补偿系统的工作原理和实现机理对半主动升沉补偿系统进行参数设计，建立半主动升沉补偿系统的仿真模型进行仿真分析。为建立动力学相似的水下铠缆相似系统要求原型和模型系统的频率相似，通过相位共振法获得实际深海水下铠缆系统原型的固有频率，经相似比例系数缩放得到铠缆模型系统的固有频率，进而确定模型系统的刚度和质量，并分别用弹簧和质量块模拟。进而设计半主动升沉补偿模型系统执行机构的主要参数，推导非对称缸电液位置伺服系统的传递函数，并分析系统的稳定性。最后，建立半主动升沉补偿模型系统的仿真模型，结合实际模型系统参数进行半主动升沉补偿仿真和性能分析，说明半主动升沉补偿方法的有效性和可行性。 (5) 搭建半主动升沉补偿模型实验平台，分别研究母船升沉运动模拟实验、水下铠缆模型系统共振放大区域实验、被动升沉补偿实验和半主动升沉补偿实验。半主动升沉补偿模型试验平台主要由母船升沉模拟装置、半主动升沉补偿装置和弹簧负载模型等组成。其中，母船升沉运动模拟装置和主动补偿装置是两套类似的电液伺服阀控非对称缸系统。在低频工作段将阀控非对称缸系统简化为比例积分环节，通过实测数据获得阀控非对称缸正反向运动的输入输出特性及非线性增益曲线，将其多段线性化后设计位置反馈加前馈的复合控制器，以提高电液控制系统的响应速度和控制精度。接着通过母船升沉模拟装置及其控制系统来模拟相似缩放和动滑轮组缩放后的实际母船升沉运动，作为弹簧负载模型系统的激励。之后分析在升沉运动激励和无任何升沉补偿时弹簧负载相似模型系统从1000至4500米对应的模拟深度下的动态响应及其共振放大区域。通过被动升沉补偿缸和母船升沉模拟装置进行被动升沉补偿实验并分析了被动升沉补偿效率。最后利用半主动升沉补偿装置来降低弹簧负载模型系统中弹簧张力和负载运动的幅度，验证半主动升沉补偿方法的有效性。 |
Other Abstract | The practical requirement of safe launch and recovery under the high sea state is considered in this paper, and the dynamic characteristics and the semi-active heave compensation technology are studied from the point of theoretical modeling and model test views. The main contents are summarized as follows: (1) The three-dimensional nonlinear finite element model of the umbilical cable is developed. Based on the Reissner-Timoshenko assumption of geometrically exact beam theory and the principle of virtual work, the weak forms of the underwater umbilical cable dynamic equations are derived. The total Lagrangian finite element formulation of the geometrically exact beam is used, where the unknown variables are centerline displacement and cross-section rotation vectors. The linearization of total Lagrangian formulation is derived via the Frechet derivative, and the discretization of the underwater umbilical cable model is obtained by using the two-node isoparametric finite element. The residual nodal force is obtained by the discretization of residual term of the elemental total virtual work, and the elemental mass matrices, tangential stiffness matrices and the load stiffness matrices are derived by the discretization of the linear increment term of the elemental total virtual work. Then, we can get the total nodal force vector and total mass matrices and stiffness matrices by assembling every finite element, and the three-dimensional nonlinear finite element equations of the umbilical cable are derived, whose top kinematical boundary condition and end dynamic boundary condition are determined for solution. (2) The numerical solution and validation of effectiveness for three-dimensional nonlinear finite element model of the umbilical cable is studied. The program named QCAB for finite element analysis is developed by using the FORTRAN language, and for contrast, the standard Newmark algorithm and generalized-alpha algorithm are utilized. According to the finite element model of underwater umbilical cable, the corresponding formulations for the standard Newmark and generalized-alpha algorithms are derived respectively, which are combined with the Newton-Raphson iterative method and the nonlinear dynamic problems with time-dependent mass matrices and stiffness matrices could be solved. The whole layout of the finite element program and the computation modules for coefficient matrices and nodal forces are given. By the calculation examples of bending out-of-plane, molding spirally and rotating in 3D space, the effectiveness of the finite element program for solving the nonlinear static steady problems and the dynamic problems is verified. Then, the validation using the really measured data of deep-sea ROV system, ROPOS, at the depth of 1730 m is done. The performance of numerical computation of the standard Newmark algorithm and generalized-alpha algorithm is analyzed contrastively, which demonstrates the correctness of presented umbilical cable model, the implicit time integration algorithm and the finite element program. (3) The dynamic characteristics of the umbilical cable system for deep-sea ROV are analyzed elaborately. The static analysis of the umbilical cable system is firstly performed, including the case of no ship heave motion and no ocean current, and the case of no ship heave motion but with steady ocean current. The results of which are used as initial conditions for dynamic analysis, which also could be classified as two types, i.e., the type of only ship heave motion and the type of both ship heave motion and ocean current. In the first type of dynamic analysis, the dynamic response and resonance phenomenon under the drive of sinusoidal heave motion and the really measured heave motion are studied respectively, which shows that the depth around 3500 m is the resonance zone of the deep-sea umbilical cable system. In the second type of dynamic analysis, the dynamic spatial configurations of umbilical cable and the heave motion and tension of both end of umbilical cable under the union action of both ship heave motion and ocean current are analyzed, which also shows that the resonance zone of the umbilical cable system is at about 3500 m. It implies that the system should not stay longer at the resonance zone and must cross it fast. (4) The parametric design and the performance analysis of the experimental platform for the semi-active heave compensation and its model are investigated. Firstly the pameters of semi-active heave compensation system are designed, and the simulation model of the system is built and analyzed. For building the similar system of underwater umbilical cable system, it requires the similarity of natural frequencies between the prototype and the model. Through the phase-cross method, the natural frequencies of prototype could be obtained. After being scaled by scale number, we can get the natural frequencies of model. Then the stiffness and mass of model system can be determined, which are simulated by springs and mass lump respectively. Based on the model system of umbilical cable system, the parameters of semi-active heave compensation platform are designed. The system transfer functions of the asymmetrical hydraulic cylinder controlled by servo valve are derived, and the system stability is analyzed. Then, the simulation models of the experimental platform for semi-active heave compensation are built by using the software AMESim. The simulation and performance analysis using the actual parameters are carried out, which show the feasibility of the presented semi-active heave compensation system. (5) The real experimental platform for semi-active heave compensation model system is built up, and the experiments of simulating the ship heave motion, the resonance zone of model system for umbilical cable, the passive heave compensation and the semi-active heave compensation are investigated respectively. The experimental platform is mainly composed of the equipment of simulating ship heave motion, the equipment of semi-active heave compensation, and the equipment of spring and mass blocks. Among them, the former two equipments are the asymmetrical hydraulic cylinder system controlled by servo valve, which can be simplified as proportion-integration block at its low frequency band. The characteristics from input to output and nonlinear gain curves of the asymmetrical hydraulic cylinder system are obtained by really measured data. Through the multiple linearizations, the composite controller consists of displacement feedback and forward back is designed, so as to improve the response rate and control precision. Then, the equipment of simulating ship heave motion and its control system are used to simulate the really measured ship heave motion that’s scaled by scale number and the sheaves, which can be used as the input for spring-mass model system. The dynamic response and its resonance zone of spring-mass model system at the simulated depths that correspond to the actual depths from 1000 m to 4500 m are analyzed without any heave compensation. The experiment of passive heave compensation is achieved by passive cylinder and the equipment of simulating ship heave motion. In order to verify the effectiveness of the semi-active heave compensation strategy, the equipment of semi-active heave compensation and its control system are used to reduce the heave amplitude of mass block. |
Language | 中文 |
Contribution Rank | 1 |
Document Type | 学位论文 |
Identifier | http://ir.sia.cn/handle/173321/14812 |
Collection | 水下机器人研究室 |
Affiliation | 1.中国科学院沈阳自动化研究所 2.中国科学院大学 |
Recommended Citation GB/T 7714 | 全伟才. 深海ROV铠缆系统动态特性与半主动升沉补偿技术研究[D]. 沈阳. 中国科学院沈阳自动化研究所,2014. |
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