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In this paper,the underwater vehicle,sling and the mother ship are considered as a single de-gree of freedom system connected by a spring.Through the analysis of this system,a physical model is es-tablished,which describes the motion of the vehicle caused by the ship motion and wave motion.Furthermore,a mathematical model based on this physical model is obtained,and a numerical solutionprogram is made.As an example,a practical launch and recovery system for an underwater robot is calcu-lated by use of the program.and the motion track of the robot is obtained. 相似文献
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海况对水下运载器吊放回收的影响 总被引：1，自引：1，他引：1
本文将水下运载器，吊索和母船看作是一个由弹簧连接的单自由度系统，通过对系统进行分析和研究，建立了水下被吊物体在吊索带动下，由吊臂端点运动引起的运动响应的物理模型、数学方程，并编制了各项参数可调的计算机程序以求解水下物体的运动轨迹。运用此程序，对影响参数作系列变化后进行了运动响应计算，并绘制成运动响应随这些参数变化的曲线，为水下吊放回收系统的设计提供了依据 相似文献
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This paper describes an effort to develop a predictive tool for the design of a new promising marine transport — the WIG craft. The presented mathematical model of the WIG craft is capable of modeling the aerodynamics of a WIG system including the ground effect, the hydrodynamics of a stepped planing hull with a hydrofoil and also the simulation of motion for the craft. Based on extensive experience using the model, it is shown that the most important and necessary features of WIG aero- and hydrodynamics are taken into account. The results of simulations have been validated through comparison with other theoretical approaches and also with model experiments. The mathematical model is applied to investigate the dynamics of the small manually piloted WIG craft: “Hydrowing VT01”. The numerical study resulted in recommendations allowing the pilot to overcome the pitch-up tendency and also to perform the take-off manoeuvre smoothly. The stability of the WIG with a hydrofoil and also the dynamic properties of anti-collision manoeuvres have been studied and are presented. 相似文献
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A three-dimensional model of a two-part underwater towed system is studied. In the model, the governing equations of cables are established based on the Ablow and Schechter method. The boundary conditions for the two-part underwater towed system are derived. The six-degrees-of-freedom equations of motion for submarine simulations are adopted to predict the hydrodynamic performance of a towed vehicle. The established governing equations for the system are then solved using a central finite difference method. In this paper several algorithms are used to solve this special form of finite difference equations. The results in this paper indicate that the two-part underwater towed system improves the dynamic behavior of the towed vehicle and is an easy way to decouple the towing ship motion from the towed vehicle. Because the model uses an implicit time integration, it is stable for large time steps and is an effective algorithm for simulation of a large-scale underwater towed system. 相似文献
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The authors developed a pendulum inclinometer suitable for use with small deep-submersibles or surface craft. The instrument uses a relatively short heavy pendulum and a viscous damping system for minimizing the effects of unwanted oscillatory motion. The pendulum relative motion is transmitted to the dial pointer through a flexible cord. The mechanism is designed so that the inclinometer gives a direct reading of the tangent of the angle of inclination. Adjustments are provided for levelling the instrument and for setting the dial to zero. Upper and lower clamping devices protect the pendulum suspension from damage during transit. The inclinometer has been used successfully in recent inclining experiments for the small research submarine Alvin. 相似文献
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当安装于水下航行体上的旋转装置质量或转动惯量达到一定程度时,其对水下航行体运动与操纵的影响是不可忽略的。针对安装于水下航行体上的旋转装置,分析了水下航行体运动时装置的陀螺效应。得出了旋转装置陀螺力的明确数学方程。不失方法的一般性,假设旋转装置只在运动坐标系的X轴方向有旋转角速度,推导了在考虑陀螺效应作用的情况下水下航行体的六自由度模型方程;以此为基础,建立了水下航行体的仿真模型并对水下航行体的水下运动特性进行了仿真,分析了旋转装置的质量、角速度对水下航行体运动特性的影响规律,从而为研究在考虑陀螺效应情况下的水下航行体操纵奠定了基础。 相似文献
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航行体近水面滑跳运动是近年来跨介质航行体研究的热点问题之一,针对航行体水面滑跳运动现象开展研究。 首先设计了适宜滑跳的航行体构型,通过数值仿真方法确定航行体的主要技术参数,发现航行体滑跳过程对于重心位置非常敏感;然后,针对设计的构型,开展水面自由滑跳试验,试验表明本文设计的模型可以在近水面稳定滑跳,验证了滑跳运动方式的可行性。 工作可为后续跨介质航行体设计提供技术参考。 相似文献
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A hydrodynamic model of a two-part underwater manoeuvrable towed system is proposed in which a depressor is equipped with active horizontal and vertical control surfaces, and a towed vehicle is attached to the lower end of a primary cable. In such a system the towed vehicle can be manoeuvred in both vertical and horizontal planes when it is towed at a certain velocity and the coupling effect of excitations at the upper end of the primary cable and disturbances of control manipulations to the towed vehicle can be reduced. In the model the hydrodynamic behavior of an underwater vehicle is described by the six-degrees-of-freedom equations of motion for submarine simulations. The added masses of an underwater vehicle are obtained from the three-dimensional potential theory. The control surface forces of the vehicle are determined by the wing theory. The results indicate that with relative simple control measures a two-part underwater manoeuvrable towed system enables the towed vehicle to travel in a wide range with a stable attitude. The method in this model gives an effective numerical approach for determining hydrodynamic characteristics of an underwater vehicle especially when little or no experimental data are available or when costs prohibit doing experiments for determining these data. 相似文献
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This paper describes the estimation of hydrodynamic coefficients and the control algorithm based on a nonlinear mathematical modeling for a test bed autonomous underwater vehicle (AUV) named by SNUUV I (Seoul National University Underwater Vehicle I).A six degree of freedom mathematical model for SNUUV I is derived with linear and nonlinear hydrodynamic coefficients, which are estimated with the help of a potential code and also the system identification using multi-variable regression.A navigation algorithm is developed using three ranging sonars, pressure sensor and two inclinometers keeping towing tank applications in mind. Based on the mathematical model, a simulation program using a model-based control algorithm is designed for heading control and wall following control of SNUUV I.It is demonstrated numerically that the navigation system together with controller guides the vehicle to follow the desired heading and path with a sufficient accuracy. Therefore the model-based control algorithm can be designed efficiently using the system identification method based on vehicle motion experiments with the appropriate navigation system. 相似文献
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The equations of motion for the coupled dynamics of a small liferaft and fast rescue craft in a surface wave are formulated in two dimensions using the methods of Kane and Levinson [1985. Dynamics: Theory and Applications. McGraw-Hill Inc., New York]. It is assumed that the motion normal to the wave surface is small and can be neglected, i.e. the bodies move along the propagating wave profile. The bodies are small so that wave diffraction and reflection are negligible. A Stokes second order wave is used and the wave forces are applied using Morison's equation for a body in accelerated flow. Wind loads are similarly modelled using drag coefficients. The equations are solved numerically using the Runge–Kutta routine “ode45” of MATLAB®. The numerical model provides guidelines for predicting the tow loads and motions of small craft in severe sea states. 相似文献
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《Oceanic Engineering, IEEE Journal of》2008,33(2):59-68
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Przemysław Herman 《Ocean Engineering》2009,36(3-4):306-312
A method for dynamics investigation and coupling detection between velocities of autonomous underwater vehicles (AUVs) is presented in this paper. The method is based on transformation of equations of motion, which are usually used for an underwater vehicle, into equations with a diagonal mass matrix. The obtained equations contain quasi-velocities and allow one to give a further insight into the AUV dynamics especially for an underactuated system. Some advantages of the proposed approach are discussed, too. An analytical example for a 3-DOF AUV shows possible application of the transformed equations. Moreover, the given approach is validated via simulation on a 6-DOF vehicle. 相似文献
16.
Pan-Mook Lee Seok-Won Hong Yong-Kon Lim Chong-Moo Lee Bong-Hwan Jeon Jong-Won Park 《Oceanic Engineering, IEEE Journal of》1999,24(3):388-395
This paper presents a discrete-time quasi-sliding mode controller for an autonomous underwater vehicle (AUV) in the presence of parameter uncertainties and a long sampling interval. The AUV, named VORAM, is used as a model for the verification of the proposed control algorithm. Simulations of depth control and contouring control are performed for a numerical model of the AUV with full nonlinear equations of motion to verify the effectiveness of the proposed control schemes when the vehicle has a long sampling interval. By using the discrete-time quasi-sliding mode control law, experiments on depth control of the AUV are performed in a towing tank. The controller makes the system stable in the presence of system uncertainties and even external disturbances without any observer nor any predictor producing high rate estimates of vehicle states. As the sampling interval becomes large, the effectiveness of the proposed control law is more prominent when compared with the conventional sliding mode controller 相似文献
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During severe storms, evacuation systems for offshore rigs and platforms currently in use have proven themselves to be inadequate. Typically, during deployment of a lifeboat, it is often damaged to the point of not being seaworthy before it reaches the ocean surface. This is especially the case for cable-launched boats where a pendulum-like motion of the craft on its cables is often set up. It is less of a problem for free-fall lifeboats. Even when a craft reaches the ocean surface intact, high winds and waves can drive it back against the rig/platform structure. This paper describes the state-of-the-art of evacuation. It focuses on two new systems being developed by the authors in Newfoundland, Canada. 相似文献
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Observability of target tracking with range-only measurements 总被引：1，自引：0，他引：1
Taek Lyul Song 《Oceanic Engineering, IEEE Journal of》1999,24(3):383-387
A necessary and sufficient condition for local system observability, a prerequisite to target motion analysis, is presented in this technical communication for two-dimensional manoeuvring target tracking with range-only measurements from a single observer. The approach taken in this paper utilizes the Fisher information matrix developed from the analytical treatment of system dynamics and noisy measurement equations established in a modified polar coordinate system. The analytical results of this paper are demonstrated by a series of simulation studies for applications on naval surface vehicle engagements 相似文献
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Peter R. Payne 《Ocean Engineering》1984,11(2):129-184
This paper gives an overview of the development of the supercritical planing hull concept during the last two decades. Our starting point was the body of theoretical and tank testing work on supercritical displacement ships which was completed by Lewis and others by 1960. In 1964 we launched a manned model small waterplane twin hull (SWATH) craft having a very low pitch stiffness, and thus very little pitching motion at wave encounter frequencies above resonance. A second craft was launched the following year, after which we changed the emphasis of our program to the higher speeds associated with planning craft. Planning catamarans occupied us between 1967 and 1971, when the first Sea Knife monohull supercritical planning hull was launched. The most recent Sea Knife is 34 ft L.O.A., displaces 16,000 lb with full fuel and crew, has been timed at 80 mph in sea state 3, and (from model tests) can do the same in sea state 4 with a comfortable ride. We conclude that supercritical planing hulls are very suitable for high speed ferries, patrol craft and crewboats, and that the technology is now mature. 相似文献