scholarly journals Determination of Flow Parameters of a Water Flow Around an AUV Body

Robotics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Julian Hoth ◽  
Wojciech Kowalczyk
Keyword(s):  
Water Flow ◽  
Autonomous Underwater Vehicles ◽  
Pressure Sensors ◽  
Underwater Vehicles ◽  
Support Vector ◽  
Navigation Systems ◽  
Pressure Data ◽  
Flow Parameters ◽  
Wide Range ◽  
The Given

Autonomous underwater vehicles (AUVs) have changed the way marine environment is surveyed, monitored and mapped. Autonomous underwater vehicles have a wide range of applications in research, military, and commercial settings. AUVs not only perform a given task but also adapt to changes in the environment, e.g., sudden side currents, downdrafts, and other effects which are extremely unpredictable. To navigate properly and allow simultaneous localisation and mapping (SLAM) algorithms to be used, these effects need to be detected. With current navigation systems, these disturbances in the water flow are not measured directly. Only the indirect effects are observed. It is proposed to detect the disturbances directly by placing pressure sensors on the surface of the AUV and processing the pressure data obtained. Within this study, the applicability of different learning methods for determining flow parameters of a surrounding fluid from pressure on an AUV body are tested. This is based on CFD simulations using pressure data from specified points on the surface of the AUV. It is shown that support vector machines are most suitable for the given task and yield excellent results.

scholarly journals A Low-Cost Electromagnetic Docking Guidance System for Micro Autonomous Underwater Vehicles

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 682 ◽  
Author(s):  
Shilin Peng ◽  
Jingbiao Liu ◽  
Junhao Wu ◽  
Chong Li ◽  
Benkun Liu ◽  
...  
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Guidance System ◽  
Electromagnetic Signal ◽  
Spatiotemporal Resolution ◽  
Search Coil ◽  
Wide Range ◽  
Processing Subsystem

As important observational platforms for the Smart Ocean concept, autonomous underwater vehicles (AUVs) that perform long-term observation in fleets are beneficial because they provide large-scale sampling data with a sufficient spatiotemporal resolution. Therefore, a large number of low-cost micro AUVs with docking capability for power recharge and data transmission are essential. This study designed a low-cost electromagnetic docking guidance (EMDG) system for micro AUVs. The EMDG system is composed of a transmitter coil located on the dock and a three-axial search coil magnetometer acting as a receiver. The search coil magnetometer was optimized for small sizes while maintaining sufficient sensitivity. The signal conditioning and processing subsystem was designed to calculate the deflection angle (β) for docking guidance. Underwater docking tests showed that the system can detect the electromagnetic signal and successfully guide AUV docking. The AUV can still perform docking in extreme positions, which cannot be realized through normal optical or acoustic guidance. This study is the first to focus on the EM guidance system for low-cost micro AUVs. The search coil sensor in the AUV is inexpensive and compact so that the system can be equipped on a wide range of AUVs.

The Base Pressure Problem in Transonic Turbine Cascades

1979 ◽  
Author(s):  
C. H. Sieverding ◽  
M. Stanislas ◽  
J. Snoek
Keyword(s):  
Theoretical Calculations ◽  
Base Pressure ◽  
Test Results ◽  
Pressure Data ◽  
Calculation Methods ◽  
Flow Parameters ◽  
Wide Range ◽  
Pressure Calculation ◽  
Transonic Turbine ◽  
Turbine Cascades

Base pressure data were systematically collected at VKI during recent years on a great variety of cascades operated over a wide range of outlet March numbers. An attempt is made to correlate these data by relating the base pressure to important cascade and flow parameters. Details about the trailing edge flow are obtained by using an enlarged model simulating the overhang section of convergent turbine cascades. The experimental cascade and model test results are compared with theoretical calculations using base pressure calculation methods.

scholarly journals Swarm optimization approach to non-stationary physical eld survey problem using a group of autonomous underwater vehicles

2020 ◽  
Author(s):  
A. Tolstikhin ◽  
I. Bychkov
Keyword(s):  
Optimization Problem ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Grey Wolf Optimizer ◽  
Optimization Approach ◽  
Vast Number ◽  
Swarm Algorithms ◽  
Whale Optimization ◽  
Low Dimensional ◽  
The Given

The paper considers the problem of searching for the source of a non-stationary physical eld. We assume that the use of swarm algorithms may be applicable in this case. A hybrid of the Whale Optimization Algorithm and Grey Wolf Optimizer is proposed in this paper. The algorithm has several advantages over its origins: a more precise solution of the optimization problem for low-dimensional functions and a higher convergence rate of the first iterations. Two modications were made to adapt the algorithm to the requirements of the problem. The proposed algorithm is used as a basis for a control strategy for a group of autonomous underwater vehicles. As a result, in the vast number of cases, the group can find the source within the given number of search iterations.

scholarly journals Wireless Remote Control for Underwater Vehicles

2020 ◽  
Vol 8 (10) ◽  
pp. 736
Author(s):  
Filippo Campagnaro ◽  
Alberto Signori ◽  
Michele Zorzi
Keyword(s):  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Communication Link ◽  
Strong Impact ◽  
Underwater Sensor Networks ◽  
Navigation Systems ◽  
Underwater Communication ◽  
Commercial Off The Shelf ◽  
The Stability ◽  
New Applications

Nowadays, the increasing availability of commercial off-the-shelf underwater acoustic and non-acoustic (e.g., optical and electromagnetic) modems that can be employed for both short-range broadband and long-range low-rate communication, the increasing level of autonomy of underwater vehicles, and the refinement of their underwater navigation systems pave the way for several new applications, such as data muling from underwater sensor networks and the transmission of real-time video streams underwater. In addition, these new developments inspired many companies to start designing hybrid wireless-driven underwater vehicles specifically tailored for off-shore operations and that are able to behave either as remotely operated vehicles (ROVs) or as autonomous underwater vehicles (AUVs), depending on both the type of mission they are required to perform and the limitations imposed by underwater communication channels. In this paper, we evaluate the actual quality of service (QoS) achievable with an underwater wireless-piloted vehicle, addressing the realistic aspects found in the underwater domain, first reviewing the current state-of-the-art of communication technologies and then proposing the list of application streams needed for control of the underwater vehicle, grouping them in different working modes according to the level of autonomy required by the off-shore mission. The proposed system is finally evaluated by employing the DESERT Underwater simulation framework by specifically analyzing the QoS that can be provided to each application stream when using a multimodal underwater communication system specifically designed to support different traffic-based QoSs. Both the analysis and the results show that changes in the underwater environment have a strong impact on the range and on the stability of the communication link.

scholarly journals MOTION ESTIMATION OF AN UNDERWATER PLATFORM USING IMAGES FROM TWO SONAR SENSORS

2021 ◽  
Author(s):  
José Enrique Almanza-Medina ◽  
Benjamin Henson ◽  
Yuriy Zakharov
Keyword(s):  
Motion Estimation ◽  
Performance Improvement ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
High Accuracy ◽  
Estimation Accuracy ◽  
Navigation Systems ◽  
Sonar Sensors ◽  
Acoustic Images ◽  
Single Sensor

Many underwater applications that involve the use of autonomous underwater vehicles require accurate navigation systems. Image registration from acoustic images is a technique that can be used to achieve this task by comparing two consecutive sonar images and estimate the motion of the vechicle. The use of deep learning (DL) techniques for motion estimation can significantly reduce the processing complexity and achieve high-accuracy position estimates. In this paper we investigate the performance improvement when using two sonar sensors compared to using a single sensor. The DL network is trained using images generated by a sonar simulator. The results show an improvement in the estimation accuracy when using two sensors.

scholarly journals Algorithm for dynamic formation of a single raster photo map of the seabed during the movement of an autonomous underwater vehicle

2021 ◽  
Vol 2091 (1) ◽  
pp. 012054
Author(s):  
A A Timoshenko ◽  
A V Zuev ◽  
E S Mursalimov
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Autonomous Underwater Vehicles ◽  
Real Data ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Navigation Systems ◽  
Geometric Transformations ◽  
Graphical Information ◽  
Dynamic Formation

Abstract An algorithm has been developed for creating a single raster map of the seabed from photos obtained from vertically downward cameras of autonomous underwater vehicles (AUV) using tile graphics. The images obtained during the movement of AUV are combined into a single scalable photo map, divided into square segments (tiles). This representation of graphical information allows to quickly access the images with specialized tools after lifting the AUV to the surface and reduce the time spent by the operator to analyze the results of the mission. The images were combined using simple geometric transformations based on the data received from the navigation systems of the underwater vehicle and the parameters of its camera. The efficiency of the algorithm was tested on real data taken from a marine expedition.

An Approach to Tagging Objects of Interest in Oceanic Environments Through the Use of an AUV

2017 ◽  
Author(s):  
Benjamin Waltuch ◽  
Elizabeth Astle ◽  
Eric Mirante ◽  
Brent Cornwall ◽  
James McCusker ◽  
...  
Keyword(s):  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Underwater Robotics ◽  
Test Results ◽  
Remotely Operated Vehicle ◽  
Neutral Buoyancy ◽  
Wide Range ◽  
Novel Design ◽  
Lengthy Process ◽  
The Ideal

In the field of underwater robotics, Autonomous Underwater Vehicles (AUV) have made many advancements in operating depth, mission endurance, and acoustic range making them the ideal vehicle for surveying and searching for any Object of Interest (OOI) over large areas of water. The downside to this technology is that the operator must wait for the vehicle’s mission to end to determine whether an OOI has been identified. Additionally, if an OOI is identified this object will need to be found again. The solution to this lengthy process is to equip the AUV with a suite of Underwater Locator Beacons (ULB) which can be deployed and anchored next to any positively identified OOI. This way, the operator can be actively listening for the pinging frequency of a deployed ULB where then a secondary Remotely Operated Vehicle (ROV) can be launched to retrieve or further investigate the OOI while the AUV continues its search and tag. This paper presents the design and test of a ULB deployment system that would be implemented into an AUV. An AUV is sensitive to changes in weight, therefore this novel design leverages the concepts of Archimedes Principle by preserving neutral buoyancy pre- and post-deployment of the ULB. Upon deployment, the ULB will be capable of securely anchoring itself in a wide range of seabed environments. To test the design described above, a custom ROV has been fabricated with the sole purpose of transporting the ULB deployment system to operating depth. The paper describes in detail both the test results from the ULB deployment system and a design for implementation into an AUV.

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