共查询到20条相似文献,搜索用时 31 毫秒
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Toshihiro Maki Tamaki Ura Takashi Sakamaki 《Journal of Marine Science and Technology》2012,17(4):523-531
This paper proposes a path-planning and guidance strategy for an autonomous underwater vehicle (AUV) to perform detailed inspections of jacket structures such as the support legs of offshore platforms. Inspections of such structures are important for maintenance, security, and environmental assessment. These tasks can be carried out at a less cost by using AUVs than through conventional methods. The path-planning method generates a set of waypoints to facilitate the complete coverage of the surface of the target from a constant distance based on the given information about the configurations of both the target and the vehicle. The guidance method actually controls the vehicle such that it follows the waypoints, under the assumption that the position and attitude of the vehicle are being estimated in real time with adequate accuracy. By combining these methods with the localization method we had previously proposed (Maki et al., J Mar Sci Technol [1]) an AUV can perform a fully autonomous observation of jacket structures with prior knowledge of only their configuration. The performance of the method was verified though tank experiments using the AUV Tri-Dog 1. A simple model of a jacket was installed in a test tank, and the vehicle succeeded in inspecting the target. 相似文献
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Station keeping control of remotely operated vehicles is crucial in the successful completion of underwater missions of work class robotic vehicles. The conventional method of station keeping using the vehicle pose/velocity measurement introduces delay in vehicle control and often leads to instability. In this paper, we present a novel method for measuring the underwater disturbances and controlling the robot for station keeping using a feed-forward control strategy. A strain-gauge based disturbance force measurement is proposed here with suitable algorithms to measure the forces acting on the vehicle due to external disturbances. Using the dynamic models, the vehicle response is predicted and a feed-forward control is implemented for station keeping. The controller activates corrective control action even before the vehicle responds to the disturbances. The performance of the controller is analyzed through simulation studies as well as hardware-in-loop tests. Results show that this approach is an effective alternative for conventional station keeping control of underwater vehicles. 相似文献
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《船舶与海洋工程学报》2021,(2)
There is much need for autonomous underwater vehicles(AUVs) for inspection and mapping purposes.Most conventional AUVs use torpedo-shaped single-rigid hull,because of which their manoeuvrability is limited.Moreover,any increase in payload results in a larger hull size and the turning diameter,limiting its operation in constrained areas.As a solution to this problem,we develop M-Hull,a subsurface mapping AUV with a modular-split hull design that provides better manoeuvrability than a conventional torpedo-shaped vehicle.At the same time,it has more agility than an unconventional bio-inspired snake-like vehicle though their designs look similar.This approach makes it a hybrid solution between conventional torpedo-shaped AUVs and unconventional bio-inspired vehicles.We focus on improving the turning diameter during the mapping operation,and hence this paper concentrates on the dynamic aspects of the 2 D turning motion of the vehicle.It will provide the relationship between turning speed,thrust,and joint torque requirements for the multi-hull underwater vehicle.Different turning modes are compared to choose an optimum turning configuration,and the critical speed is calculated for the vehicle's safe operation.In the end,the modelling is verified using the experimental data.One can follow the method followed here for the 2 D motion analysis of similar underwater vehicles. 相似文献
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当水下航行器利用舵机改变航向时,舵机的开启会产生很大的瞬态辐射噪声。因此,在舵机安装之前,有必要对舵机的源特性进行评估。文章基于某水下航行器的舵机振动测试试验,应用频域载荷识别中的最小二乘法方法和短时傅里叶变换的信号处理技术,对舵机操舵过程中舵机与试验台架连接的机脚点处的瞬态最大激励力和整体平均激励力分别进行了间接估算,并将估算结果的准确性和可行性进行了验证。考虑到加肋圆柱壳是水下航行器的基本结构形式,文中将估算的激励力结果作为辐射声计算的近似输入,以一个两端简支的加肋圆柱壳体作为水下航行器的一个舱段的计算模型,分别计算了舵机操舵过程中水下瞬态最大和整体平均辐射噪声的大小,提出了一种利用短时傅里叶变换信号处理技术来评估舵机水下瞬态辐射噪声的方法。 相似文献
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Bing Sun Daqi Zhu Feng Ding Simon X. Yang 《Journal of Marine Science and Technology》2013,18(1):63-74
A novel hybrid control approach is presented for trajectory tracking control of unmanned underwater vehicles in this paper. The kinematic and dynamic controllers are integrated by the proposed control strategy. The paper has two objectives. Firstly, an improved backstep method is proposed to generate the virtual velocity using a bio-inspired neurodynamics model in the kinematic controller. The bio-inspired neurodynamics model is intended to smooth the virtual velocity output to avoid speed jumps of the unmanned underwater vehicle caused by tracking errors and to meet the thruster control constraints. Secondly, a new sliding-mode method is added to the dynamic controller, which is robust against parameter inaccuracy and disturbances. The combined kinematic–dynamic control law is applied to the trajectory tracking problem of two different types of unmanned underwater vehicle. Finally, simulation results illustrate the performance of the proposed controller. 相似文献
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水下拖曳系统水动力特性的计算流体力学分析 总被引:1,自引:0,他引:1
提出了一种新型的水下拖曳系统三维水动力数学模型。在该模型中拖曳缆绳的控制方程由Ablow andSchechter模型给出,Gertler and Hargen的水下运载体六自由度运动方程被用来描述拖曳体的水动力状态。通过对拖曳缆绳和拖曳体的控制方程在连接点处进行边界条件耦合,从而构成整个拖曳系统的水动力数学模型。在研究中,拖曳系统的水动力数学模型通过时间与空间的中心差分方程来逼近,每一时刻拖曳体所受的水动力通过求解Navier-Stokes方程得到。所提出的模型特别适用于拖曳体为非回转体、非流线型的主体,或必须考虑拖曳体各组成部分的水动力相互影响的情况。计算结果与相应的实验室样机试验结果的比较表明,所提出的模型可以有效地预报拖曳系统的水动力特性。利用所提出的水动力模型,对华南理工大学提出的自主稳定可控制水下拖曳体在实际海况下的数值模拟结果显示,所分析的拖曳体具有良好的运动与姿态稳定性,是一种值得开发研究的新型水下拖曳体。 相似文献
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水下运动物体在相互接近过程中的水动力计算 总被引:6,自引:1,他引:5
用面元法计算了两个水下物体在相互接近过程中对水动力的影响,给出了水动力系统系数随物体间距离的变化曲线。该计算程序经对圆球的计算值与试验值比较了得到了验证。本研究对水下双潜器的近距离协同作业和潜器在接近障碍物过程中的运动控制能够提供较好的数学模型。 相似文献
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超高速航行器在水下运动时,其大部分表面被超空泡包裹,构成了一种新的流体动力布局,运动模式和运动特性完全不同于常规水下航行器。为了分析超高速水下航行器运动的稳定性,本文对超空泡生成机理进行研究,给出描述超空泡形态的数学模型,得到不同影响因素作用下超空泡形态的变化规律。为验证超空泡实时生成效果和超高速水下航行器运动过程各种动作功能,采用Vega Prime构建三维虚拟环境,在此基础上设计超空泡视景演示系统,通过ADI仿真系统实时解算超空泡和水下航行器运动数据来驱动超空泡视景系统,逼真地演示超空泡动态生成过程以及水下航行器高速运行轨迹和“空泡+航行器”的相对运动关系等关键技术。 相似文献
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It is well known that it is difficult to explore underwater terrains using an autonomous underwater vehicle due to the varieties and complexities of underwater terrain elements. Since conventional underwater terrain coverage techniques are usually based on the assumption that the underwater surface is planar, they generate an unnecessary exploration path especially on steep sloped surfaces of ocean basins. This paper proposes a new type of coverage technique, the hybrid terrain coverage framework (HTCF), which considers various surface conditions in three-dimensional environments and generates an efficient exploration path for all environments. The HTCF incorporates a planar terrain coverage algorithm, a spiral path terrain coverage algorithm, and a hybrid decision module to recognize and select the most suitable technique depending on the sloped surface variations. Simulation results show that the proposed HTCF is more efficient than the conventional terrain coverage algorithm in terms of the energy consumption of the underwater vehicle. 相似文献
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水下航行体降噪艉翼填角的数值模拟与试验研究 总被引:1,自引:0,他引:1
为降低水下航行体噪声,研究了艉翼填角的降噪效果。分析了水下航行体艉翼接合部马蹄涡影响螺旋桨伴流场的特征,认为马蹄涡对水下航行体噪声产生了不利影响。针对某无人水下航行体(UUV)设计了一种艉翼填角,运用CFD方法对该艉翼填角优化螺旋桨伴流场的效果进行了数值模拟,结果显示伴流场轴向速度的周向不均匀度系数下降35%-62%。将艉翼填角应用于该UUV,开展航行辐射噪声测量试验,结果显示艉翼填角使UUV航行噪声总声源级降低3.4 d B,尤其对低频噪声抑制较好。 相似文献
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Valuable mineral resources are widely distributed throughout the seabed. autonomous underwater vehicles (AUVs) are preferable
to remotely-operated vehicles (ROVs) when probing for such mineral resources as the extensive exploration area makes it difficult
to maintain contact with operators. AUVs depend on batteries, so their power consumption should be reduced to extend exploration
time. Power for conventional marine instrument systems is incorporated in their waterproof sealing. External intermittent
control of this power source until termination of exploration is challenging due to limitations imposed by the underwater
environment. Thus, the AUV must have a power control system that can improve performance and maximize use of battery capacity.
The authors developed such a power control system with a three-step algorithm. It automatically detects underwater operational
states and can limit power, effectively decreasing power consumption by about 15%. 相似文献
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对于水下机器人动力学模型辨识问题,如果其观测方程的系数矩阵包含随机扰动,则其最小二乘估计一般是有偏的。为此,该文提出一种基于多传感器递推总体最小二乘融合的水下机器人动力学模型辨识算法(RTLS_F)。首先,给出了集中式总体最小二乘融合的算法;然后,在总体最小二乘框架下,推导出多传感器递推融合估计算法。通过仿真实验对RTLS_F与其它水下机器人动力学参数辨识算法进行了比较。实验结果表明,在系数矩阵和观测向量都含有误差的情况下,最小二乘融合是有偏估计且难以提高估计精度,而RTLS_F算法可以有效改善参数辨识性能。 相似文献
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Mohammad Pourmahmood Aghababa Mohammad Hossein Amrollahi Mehdi Borjkhani Electrical 《船舶与海洋工程学报》2012,11(3):378-386
In this paper,an underwater vehicle was modeled with six dimensional nonlinear equations of motion,controlled by DC motors in all degrees of freedom.Near-optimal trajectories in an energetic environment for underwater vehicles were computed using a numerical solution of a nonlinear optimal control problem(NOCP).An energy performance index as a cost function,which should be minimized,was defined.The resulting problem was a two-point boundary value problem(TPBVP).A genetic algorithm(GA),particle swarm optimization(PSO),and ant colony optimization(ACO) algorithms were applied to solve the resulting TPBVP.Applying an Euler-Lagrange equation to the NOCP,a conjugate gradient penalty method was also adopted to solve the TPBVP.The problem of energetic environments,involving some energy sources,was discussed.Some near-optimal paths were found using a GA,PSO,and ACO algorithms.Finally,the problem of collision avoidance in an energetic environment was also taken into account. 相似文献
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导管架复合式深吃水半潜平台是近年来为了适应南海恶劣海况而提出来的新型干树半潜平台概念,主要由传统的深吃水半潜平台和导管架两部分组成。导管架的设计主要是为了支撑上层甲板结构,提高平台稳性和气隙性能。文章主要针对该平台概念的垂直平面运动进行分析,对不同海况下平台系统的数值和模型试验的结果进行了对比分析,运用频域分析方法分析了该平台与传统半潜平台之间的区别。并重点分析了导管架部分对平台垂直平面内的运动造成的影响。结果表明,该平台概念较传统的半潜平台而言具有较好的垂向运动性能,而且导管架部分对平台垂直面内的运动影响较小,导管架设计的主要优势并未受到较大的折减。 相似文献
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Tadashi Ooi Yoshiaki Takahashi Hideki Kidoushi 《Journal of Marine Science and Technology》1996,1(5):274-284
The control of a remotely-operated underwater vehicle to maintain a prescribed depth in shallow water under irregular surface
waves is realized through the application of the Robust Adaptive Neuro Controller, a composite control system incorporating—together
with the conventional control algorithm—a neural network controller. This network bestows a learning capability on the system,
allowing it to deal with unanticipated disturbances that would otherwise cause erroneous behavior of the vehicle. The effectiveness
of this application is verified through mathematical simulation of a model vehicle's behavior, through experiment in a model
basin, and through simulation of the behavior of an actual remotely operated vehicle in shallow water under irregular surface
waves. Graphic data representing the learning process undergone by the neural network distinctly indicate the rising output
from the network with the progression of learning, and the vehicle's depth variation traced in terms of the mean square error
vividly show the diminution of deviation from the prescribed depth obtained with application of the neural network. Thus controlled
to maintain constant depth, under-water vehicles with power supplied externally through a tether for propulsion and for heavy-duty
operations should consolidate their advantage for such activities as maintenance of submarine structures and surveys in deep
or hazardous water. 相似文献