共查询到20条相似文献，搜索用时 14 毫秒
1.
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
2.
Wave effects on ascending and descending motions of the autonomous underwater vehicle 总被引：1，自引：0，他引：1
In the paper, a hydrodynamic model including the characteristics of maneuvering and seakeeping is developed to simulate the six-degree of freedom motions of the underwater vehicle steering near the sea surface. The corresponding wave exciting forces on the underwater vehicle moving in waves are calculated by the strip theory, which is based on the source distribution method. With the hydrodynamic coefficients relevant to the maneuvering and seakeeping, the fourth-order Runge–Kutta numerical method is adopted to solve the equations of motions and six-degrees of freedom of the motions for the underwater vehicle steering near the free surface can be obtained. The wave effect on the corresponding motions of the underwater vehicle is investigated and some interesting phenomena with respect to different wave frequencies and headings are observed. The hydrodynamic numerical model developed here can be served as a valuable tool for analyzing the ascending and descending behaviors of the underwater vehicle near the sea surface. 相似文献
3.
以7 000 m载人潜水器的工程需求为背景,以水下单目摄像机为视觉传感器,进行了水下机器人动力定位方法研究。该动力定位方法利用视觉系统测量得到水下机器人与被观察目标之间的三维位姿关系,通过路径规划、位置控制和姿态控制分解,逐步使机器人由初始位姿逼近期望位姿并最终定位于期望位姿,从而实现了机器人的4自由度动力定位。通过水池实验验证了提出的动力定位方法,并且机器人能够抵抗恒定水流干扰和人工位置扰动。同时,该动力定位方法还可以实现机器人对被观察目标的自动跟踪。 相似文献
4.
Jenhwa Guo Sheng-Wen Cheng Cheng-Yang Ying Te-Chih Liu 《Oceanic Engineering, IEEE Journal of》2003,28(1):55-61
Describes an image registration method for underwater inspection tasks. A remotely operated vehicle equipped with a video camera and a scanning sonar is used as the testbed vehicle. Each image of the underwater scene is saved along with the video camera's position and orientation. The images are then combined to create a large composite picture of the underwater structure being inspected. This method is based upon a maximum a posteriori estimation technique and provides smooth and robust estimates of image shifts. Our results demonstrate the feasibility of this highly promising underwater inspection procedure. 相似文献
5.
研究自主水下航行器系统的软变结构控制策略问题。首先分析软变结构控制系统的结构特征,利用双曲正切函数,给出控制受限情形的软变结构控制策略。其次利用Lyapunov稳定性理论,讨论自主水下航行器软变结构控制系统的稳定性,然后构造了基于双曲正切函数的软变结构控制器,给出自主水下航行器软变结构控制的具体算法。基于双曲正切函数的自主水下航行器软变结构控制系统调节精度高,响应速度快,有效地削弱了系统抖振。最后通过一个仿真实验,比较了自主水下航行器垂直深度通道的4种控制策略对系统性能的影响,从而验证了研究方法的有效性。 相似文献
6.
双功能潜水器是目前国际上比较新型的可用于深海水下观察和作业的装备。既可有缆载人／无人，又可无缆载人。该潜水器最大工作深度450m，其结构材料和结构形式与以往类似的装备不同。文章对双功能潜水器耐压壳结构和载体框架设计中的一些问题进行了探讨，提出的设计思想和计算方法，这对获得一个具有最轻结构重量的实用的双功能潜水器结构具有指导意义。 相似文献
7.
The paper addresses the problem of autonomous underwater vehicle (AUV) modelling and parameter estimation as a means to predict the dynamic performance of underwater vehicles and thus provide solid guidelines during their design phase. The use of analytical and semi-empirical (ASE) methods to estimate the hydrodynamic derivatives of a popular class of AUVs is discussed. A comparison is done with the results obtained by using computational fluid dynamics to evaluate the bare hull lift force distribution around a fully submerged body. An application is made to the estimation of the hydrodynamic derivatives of the MAYA AUV, an autonomous underwater vehicle developed under a joint Indian-Portuguese project. The estimates obtained were used to predict the turning diameter of the vehicle during sea trials. 相似文献
8.
9.
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
10.
11.
12.
13.
水声通信和测距能力是实现水下航行器准确定位的重要技术手段。当前基于水声定位的方法主要有利用测距和测向功能的水声定位技术以及水声测距辅助导航技术，二者的系统物理复杂度都比较高。本文提出了一种基于单水声信标距离量测的匹配定位方法，航行器在水声信标测距覆盖范围内，利用航行过程中多次测距信息构建测距圆序列形成位置约束，基于航位推算导航信息，将航行器在连续测距时间段内的相对航迹在圆序列上进行最优匹配，从而获得位置估计，通过对测距误差进行补偿可进一步提升定位精度。本方法所需物理系统结构复杂度低、可操作性强，仿真实验表明，该方法可以独立实现较高精度的定位。 相似文献
14.
It is shown that by implementing certain mine avoidance techniques, an underwater vehicle equipped with an obstacle avoidance sonar (OAS) and a navigation system can safely navigate an unknown minefield. The mine avoidance techniques take into account the physical limitations of the sonar and the navigation system, the maneuverability constraints on the underwater vehicle, and the required safe standoff distance from all mines. Extensive computer simulations have verified the mine avoidance capability in more than 50 different minefields. In all 50 simulations the vehicle reached a predetermined end point and maintained at least the specified, minimum safe standoff distance from each mine. The simulation accurately models the major difficulties associated with the sonar, the navigation system, and the vehicle dynamics. The sonar model includes surface, bottom, and volume reverberation; thermal, ambient, and flow noises; actual receiver and projector beam patterns; and false alarms and missed detections. The navigation system model contains the effects of biases, random noises, and scale factor errors. The vehicle dynamic model simulates angular velocities and accelerations associated with underwater vehicles 相似文献
15.
A novel self-contained navigation system has been devised for underwater vehicles operating in and around offshore installations. This system matches data from a sector-scanning sonar device to a computer model of the installation. The paper begins by highlighting the existing approaches to subsea navigation before outlining the main features of the proposed system. It then concentrates on a key component of this system which is a method for calculating the position and heading of an underwater vehicle navigating in the vincinity of tubular steel structures. An iterative solution method is presented which incorporates six degree of freedom vehicle motions and this is verified in a series of laboratory experiments with various arrangements of structural members and using a commercial sonar device. The key features, applications and performance of this method are discussed. The main conclusion is that the proposed method for calculating the position and heading of an underwater vehicle contributes towards achieving an accurate and reliable subsea navigation capability. 相似文献
16.
In this study, a dynamic modeling method for foil-like underwater vehicles is introduced and experimentally verified in different sea tests of the Hadal ARV. The dumping force of a foil-like underwater vehicle is sensitive to swing motion. Some foil-like underwater vehicles swing periodically when performing a free-fall dive task in experiments. Models using conventional modeling methods yield solutions with asymptotic stability, which cannot simulate the self-sustained swing motion. By improving the ridge regression optimization algorithm, a grey-box modeling method based on 378 viscous drag coefficients using the Taylor series expansion is proposed in this study. The method is optimized for over-fitting and convergence problems caused by large parameter matrices. Instead of the PMM test data, the unsteady computational fluid dynamics calculation results are used in modeling. The obtained model can better simulate the swing motion of the underwater vehicle. Simulation and experimental results show a good consistency in free-fall tests during sea trials, as well as a prediction of the dive speed in the swing state. 相似文献
17.
An Odyssey IIb autonomous underwater vehicle (AUV) made by Bluefin Robotics, Inc., was acquired by the Marine Physical Laboratory, Scripps Institution of Oceanography, to conduct research in underwater acoustics as well as provide a platform for other scientific studies. The original Odyssey IIb tail cone was replaced with a ducted fan, vectored thrust system installed on vehicles currently sold by Bluefin. In initial sea tests with the new thrust system, the acoustic self noise levels of the vehicle while underway were 20 to 50 dB higher than typical ocean background noise levels, preventing the vehicle's use as a receiver of low level sounds. Controlled tests were performed to characterize the radiated and vibration noise of the AUV propulsion and actuators. Once this baseline was established, changes were made, mostly to the tail cone propulsion, to decrease the vehicle's self noise. The resulting self noise levels of the AUV from 10 Hz up to 10 kHz measured while underway by a hydrophone mounted on the AUV's inner shroud now are at or below typical shallow water background noise levels except in three bands; below 250 Hz, around 500 Hz, and from 0.9 to 2.0 kHz. The goal of this paper is to describe these changes and their effects in lowering vehicle noise levels. 相似文献
18.
针对现有拖曳式水下潜器控制机构复杂、航向与姿态不容易稳定的缺陷,提出和设计了一种具有航向与姿态稳定的多自由度可控制拖曳式水下潜器样机。该样机主要由鱼雷状浮体、固定水平主翼、转角可控制襟翼、立式翼型主体等部分组成,潜器的深度控制通过控制襟翼的偏转来诱导固定水平主翼攻角的改变来实现;潜器的横荡运动操纵以通过控制两个作为转艏控制器的导管螺旋桨的转向与转速、诱导立式翼型主体产生诱导力矩使其产生横向偏转来进行。文中所提出和设计的样机具有运动过程中自我稳定能力强、航向稳定性好、控制机构简单并具有较高实用价值的特点。 相似文献
19.