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1.
This paper presents a constructive design of new controllers that force underactuated ships under constant or slow time-varying sea loads to asymptotically track a parameterized reference path, that guarantees the distance from the ship to the reference path always be within a specified value. The control design is based on a global exponential disturbance observer, a transformation of the ship dynamics to an almost spherical form, an interpretation of the tracking errors in an earth-fixed frame, an introduction of dynamic variables to compensate for relaxation of the reference path generation, p-times differentiable step functions, and backstepping and Lyapunov's direct methods. The effectiveness of the proposed results is illustrated through simulations.  相似文献   

2.
以秦皇岛港立体仓库筹建为例,针对煤炭港口备件的特点,制定了一套将自动化立体仓库应用于港口备件管理的方案,并指出应用过程中应注意的问题.  相似文献   

3.
目前,物联网是战略性新兴产业的重要组成部分,是当前世界新一轮经济和科技发展的战略制高点之一,对加快转变经济发展方式具有重要推动作用。以物联网技术促进港口智能化发展,是我国港口现代化发展的重要方向,是我国港口转变发展方式、提升港口综合竞争力的重要路径。  相似文献   

4.
The typical industry practice for Tension Leg Platform (TLP) design focuses on a conventional short-term design recipe, which assumes that an N-year design environment leads to an N-year response. In the response-based design method, the TLP is designed to withstand N-year responses rather than respond to N-year environmental conditions. In this paper, we present an overview and a general procedure for the response-based design method and use a case study to compare the critical TLP responses between the two methods. The results of our comparison show that the conventional short-term design method often contains an element of conservatism and that the response-based design method can reduce the design conditions and thereby achieve cost savings.  相似文献   

5.
国际货物运输中的隐名代理问题   总被引:1,自引:0,他引:1  
随着我国对外贸易事业的深入开展,国际贸易中的隐名代理问题亟须规范化。起源于英国的隐名代理制度,在英美法系由来已久日趋完善。世界上大多数国家都参照英国的隐名代理制度,制定了有关隐名代理的法律规范。我国目前虽然规定了一些有关隐名代理问题的实务操作办法,但缺少对隐名代理相关法律问题的明确规范,建议通过立法的形式对隐名代理制度予以完善。  相似文献   

6.
The typical industry practice for Tension Leg Platform(TLP) design focuses on a conventional short-term design recipe, which assumes that an N-year design environment leads to an N-year response. In the response-based design method, the TLP is designed to withstand N-year responses rather than respond to N-year environmental conditions. In this paper, we present an overview and a general procedure for the response-based design method and use a case study to compare the critical TLP responses between the two methods. The results of our comparison show that the conventional short-term design method often contains an element of conservatism and that the response-based design method can reduce the design conditions and thereby achieve cost savings.  相似文献   

7.
S-surface control has proven to be an effective means for motion control of underwater autonomous vehicles (AUV). However there are still problems maintaining steady precision of course due to the constant need to adjust parameters, especially where there are disturbing currents. Thus an intelligent integral was introduced to improve precision. An expert S-surface control was developed to tune the parameters on-line, based on the expert system, it provides S-surface control according to practical experience and control knowledge. To prevent control output over-compensation, a fuzzy neural network was included to adjust the production rules to the knowledge base. Experiments were conducted on an AUV simulation platform, and the results show that the expert S-surface controller performs better than an S-surface controller in environments with currents, producing good steady precision of course in a robust way.  相似文献   

8.
潜艇综合信息网是以SDH光纤环网为基础、以多业务综合为目的的信息传送平台,各应用系统的设备和用户散布在潜艇上的不同部位,它们通过接入网连到潜艇综合信息网,构成一个应用网,如作战信启、网、内部通信网、外部通信网等。在潜艇综合信息网的框架内可以很方便地构建通信支持系统,形成内外通综合的通信系统,它是一个分布式系统,具有结构简单、方便作战指挥、智能化程度高的特点,可以充分实现潜艇通信自动化。  相似文献   

9.
航母编队装备体系的效能模型研究   总被引:1,自引:1,他引:0  
卜广志 《舰船科学技术》2007,29(1):99-103,107
将航母编队装备视为一个装备体系进行分析,使用串联、互补、协同3种结构要素,分析了航母编队装备体系的体系结构。根据航母编队装备体系结构和各组成装备效能,建立了评估装备体系效能的数学模型。算例表明此数学模型具有一定的有效性。  相似文献   

10.
文章介绍了在某大型引进船舶中应用GJB1378制定船机电设备和系统预防性维修大纲的过程和方法,并对其效果进行了评估.  相似文献   

11.
This research is intended to provide academic reference and design guidance for further studies to determine the most effective means to reduce a ship’s resistance through an air-cavity. On the basis of potential theory and on the assumption of an ideal and irrotational fluid, this paper drives a method for calculating air cavity formation using slender ship theory then points out the parameters directly related to the formation of air cavities and their interrelationships. Simulations showed that the formation of an air cavity is affected by cavitation number, velocity, groove geometry and groove size. When the ship’s velocity and groove structure are given, the cavitation number must be within range to form a steady air cavity. The interface between air and water forms a wave shape and could be adjusted by an air injection system.  相似文献   

12.
Stress evaluation of a submerged floating tunnel (SFT) is an issue important for determining the section dimensions required to resist environmental loads. However, the complex interaction between an SFT and surrounding fluid has confined most research on SFTs to longitudinal global time-history analyses based on Morison's equation [1]. Even though these analyses give sufficient information in the longitudinal direction, too little information about the circumferential direction compels an SFT section to be designed conservatively. This means that SFT design requires additional information on the structural behavior of the tunnel in the circumferential direction for efficient design. Accordingly, a supplementary approach by which to obtain structural responses in the circumferential direction is introduced in this paper. Upon consideration of the static responses equivalent to the dynamic behavior, three-dimensional (3-D) finite-element analyses of an SFT were performed by application of static loads corresponding to dynamic loads equivalent to those of wave, current and earthquake. The validation of each equivalent static load was supported by the results from comparison of the tension forces in mooring lines obtained using OrcaFlex [2] and ABAQUS [3]. These were used mainly for longitudinal dynamic analysis and 3-D stress evaluation, respectively, of an SFT. Based on the stresses obtained in the longitudinal and circumferential directions, the selection of suitable section dimensions for an SFT is considered.  相似文献   

13.
A Chebyshev fitting way for a propeller atlas across four quadrants is discussed. As an example, Chebyshev polynomialfitting results and its error analysis are given. Because it's difficult generally to get a propeller atlas across four quadrants,a wayis used to construct an alternative with higher accuracy based on the properties. As an application example, an alternative forthe propeller property of a Deep Submergence Vebicle across four quadrants is given practically and a simulation model of the  相似文献   

14.
Plates form one of the basic elements of structures. Land-based structures may be subjected to air blast loads during combat environment or terrorist attack, while marine structures may be subjected to either air blast by the attack of a missile above the water surface or an underwater explosion by the attack of a torpedo or a mine or a depth charge and an aircraft structure may be subjected to an in-flight attack by on-board explosive devices. Furthermore, gas explosion occurs in offshore installations and industries. This review focuses on the phenomenological evolution of blast damage of plates.  相似文献   

15.
运用主成分分析方法,经过矩阵变换,提取振动信号的主要信息,从而实现对振动噪声源的分析。通过对100CLG-30船用立式单级离心泵试验数据的分析处理说明,在有用信息量损失较少的前提下,该方法可以提炼运转状态信息,是一种解决高维复杂系统状态分析问题的简便有效的统计方法。  相似文献   

16.
This paper reports a study on hull sizing for tension leg platforms (TLPs) using an optimization model. At the conceptual or basic design stage of an offshore platform project, hull sizing is one of the most important tasks, having a great impact on later stages of the project. Hull sizing is usually done by an engineering team combining several disciplines and taking account of factors including hydrodynamics, global performance, stability, and structure. This makes it difficult and time-consuming to optimize the hull dimensions. In this study, hull sizing was modeled as an optimization problem in which a range of design criteria had to be satisfied and an objective function minimized. Sizing was then performed using optimization algorithms. For each module, the result calculated by our method was compared with that produced by commercial software (DNV Sesam). Our system was tested for conventional TLP design in three specific metocean environments. Finally, our optimized hull shape was compared with an existing TLP, and the difference in hull shape demanded by each environment was analyzed.  相似文献   

17.
Contrary to most signal decomposition methods that usually decompose an original signal into a series of components simultaneously, a novel approach based on repeated extraction of Maximum Energy Component (MEC) is proposed. The approach starts from determination of the MEC referring to the estimated Power Spectral Density (PSD) function, and then represents the MEC by employing an exponential function to fit the original signal. By defining a stopping criterion based on two adjacent estimated PSDs, each MEC can be accurately extracted with an improved performance throughout the entire signal decomposition. To verify the proposed method, a single degree-of-freedom system subject to harmonic loads has been examined. Numerical results show that the analytical response can not only be decomposed into four MECs corresponding to the excitation and the system, respectively, but also provide an accurate estimation of natural frequency and damping ratio of the system. Meanwhile, by observing results from the Ensemble Empirical Mode Decomposition (EEMD), Variational Mode Decomposition (VMD) and Prony based on state-space model (Prony-SS), an improved decomposition accuracy has been achieved from the proposed approach. Furthermore, experimental data from the Norwegian Deepwater Programme and two sets of field-test data from one fixed offshore platform and an offshore wind turbine have been used to demonstrate the correctness of the developed signal decomposition method. It is noted that divergence in results by Prony-SS can be observed when a very large model order is used, while the proposed method provides the better decomposition and reconstruction of signals.  相似文献   

18.
鲍峰  程效军 《船舶工程》2001,(6):12-15,19
利用反射片作为瞄准目标的电子全站仪用于工业产品不规则外形检测和设计参数测定,需要解决的问题是:指定点位的测设,大地三维坐标的测定,大地坐标系和工业设计独立坐标系的转换,图形的制作和参数计算,本文介绍利用电子全站仪测定舰艇螺旋桨的外形尺寸及叶片参数的理论、方法和实测结果。  相似文献   

19.
This work describes an enhanced mooring optimization procedure, oriented towards recent floating production systems (FPS) for oil & gas exploitation in ultra-deep-water scenarios, which may present a large number of risers in an asymmetric layout. Acknowledging that the risers are the key component of an FPS, the optimization procedure is associated to an integrated mooring-riser design methodology; thus, instead of simply minimizing the platform offsets and/or the costs of the mooring system itself, one of the main objectives is to obtain a mooring configuration that ensures the integrity of the risers. Other highlights of the optimization procedure include the following aspects: Enhancements in the modeling of the optimization problem (including the definition of design variables, objective function and constraints that are relevant for such actual applications); The use of the PSO optimization algorithm associated to the ε-constrained method to efficiently handle the constraints; Enhancements in the evaluation of candidate solutions, by full nonlinear time-domain dynamic Finite Element simulations with coupled models; and the implementation in a parallel computing environment to deal with the high associated computational costs. A case study considering an FPS representative of actual applications in deepwater scenarios is presented to illustrate the practical application of the optimization tool.  相似文献   

20.
本文通过对一种新型四柱式SPAR平台扶正和服役状态时的压载总体方案研究,设计了一种借助海水压载的扶正方案以及服役状态时的可调压载系统方案。该方案可有效的实现平台自身的扶正并满足服役作业状态的压排载要求。  相似文献   

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