scholarly journals Algorithm of Berthing and Maneuvering for Catamaran Unmanned Surface Vehicle Based on Ship Maneuverability

2021 ◽  
Vol 9 (3) ◽  
pp. 289 ◽  
Author(s):  
Gongxing Wu ◽  
Mingyuan Zhao ◽  
Yu Cong ◽  
ZhiWen Hu ◽  
Guofu Li
Keyword(s):  
Simulation Experiment ◽  
Wind Waves ◽  
Simulation Software ◽  
Turning Process ◽  
Unmanned Surface Vehicle ◽  
Development Platform ◽  
Ship Maneuverability ◽  
Waves And Currents ◽  
Turning Radius ◽  
The Right

In the complex port environment, ship berthing manipulation is one of the most difficult operations. In this study, an algorithm of berthing and maneuvering was designed for a catamaran unmanned surface vehicle (USV), which is used for port patrol and protection. Considering the influence of wind, waves, and currents, the mathematical model of the maneuvering movement for the twin-hull and twin-propeller USV was established. Based on the Visual Studio development platform, the USV’s berthing manipulation simulation software was designed. Through the turning simulation experiment of the catamaran USV under different differential rotation speeds of the twin propellers, the relationship between the ship’s turning radius and the propeller speed difference was obtained. A simulation experiment of decelerating and stopping ships at different speeds was carried out, which can provide a reference for speed control when berthing. A berthing maneuvering algorithm based on ship maneuverability was proposed. USV’s berthing algorithm includes three stages: approach process, turning process, and berthing process. In the approach process, the appropriate approach speed was select according to the rotation angle. In the turning process, the right and left propeller speed differences were select. In the berthing process, the berthing speed was controlled according to the berthing distance. In the port environment, a berthing simulation experiment for catamaran USV was carried out. The simulation results show that based on the berthing and maneuvering algorithm, the efficiency and safety of catamaran USV berthing can be improved.

scholarly journals An Algorithm for Path Planning of Autonomous Ships Considering the Influence of Wind and Wave

2021 ◽  
Vol 2083 (3) ◽  
pp. 032028
Author(s):  
Yucheng Zhou ◽  
Yan Gong ◽  
Xiongfei Geng ◽  
Dongsheng Li ◽  
Beili Gao ◽  
...  
Keyword(s):  
Path Planning ◽  
Simulation Experiment ◽  
Fitness Function ◽  
Wind Waves ◽  
Optimal Path ◽  
Influence Factors ◽  
Pso Algorithm ◽  
Matlab Simulation ◽  
Waves And Currents ◽  
Global Optimal

Abstract Aiming at the problem that external factors such as wind, waves and currents are not considered in the path planning of autonomous sailing ships, which affect the safety of navigation, an improved particle swarm optimization algorithm is proposed. Introduce adaptive inertia weight to improve the convergence of the algorithm, wind and wave influence factors in the algorithm fitness function, increase the wind and wave resistance of the path, and improve the safety of the path. MATLAB simulation experiment results show that the optimized PSO algorithm can obtain the global optimal path and improve the safety of the path.

scholarly journals Right-sided Bochdalek hernia in an adult with hepatic malformation and intestinal malrotation

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Naoki Enomoto ◽  
Kazuhiko Yamada ◽  
Daiki Kato ◽  
Shusuke Yagi ◽  
Hitomi Wake ◽  
...  
Keyword(s):  
Elective Surgery ◽  
Abdominal Cavity ◽  
Three Dimensional ◽  
Simulation Software ◽  
3D Simulation ◽  
Diaphragmatic Defect ◽  
Intestinal Malrotation ◽  
Intestinal Loop ◽  
Bochdalek Hernia ◽  
The Right

Abstract Background Bochdalek hernia is a common congenital diaphragmatic defect that usually manifests with cardiopulmonary insufficiency in neonates. It is very rare in adults, and symptomatic cases are mostly left-sided. Diaphragmatic defects generally warrant immediate surgical intervention to reduce the risk of incarceration or strangulation of the displaced viscera. Case presentation A 47-year-old woman presented with dyspnea on exertion. Computed tomography revealed that a large part of the intestinal loop with superior mesenteric vessels and the right kidney were displaced into the right thoracic cavity. Preoperative three-dimensional (3D) simulation software visualized detailed anatomy of displaced viscera and the precise location and size of the diaphragmatic defect. She underwent elective surgery after concomitant pulmonary hypertension was stabilized preoperatively. The laparotomic approach was adopted. Malformation of the liver and the presence of intestinal malrotation were confirmed during the operation. The distal part of the duodenum, jejunum, ileum, colon, and right kidney were reduced into the abdominal cavity consecutively. A large-sized oval defect was closed with monofilament polypropylene mesh. No complications occurred postoperatively. Conclusion Symptomatic right-sided Bochdalek hernia in adults is exceedingly rare and is frequently accompanied by various visceral anomalies. Accurate diagnosis and appropriate surgical repair are crucial to prevent possible incarceration or strangulation. The preoperative 3D simulation provided comprehensive information on anatomy and concomitant anomalies and helped surgeons plan the operation meticulously and perform procedures safely.

Optimum Ship Routing

1960 ◽  
Vol 13 (3) ◽  
pp. 253-272 ◽  
Author(s):  
George L. Hanssen ◽  
Richard W. James
Keyword(s):  
United States ◽  
Travel Time ◽  
Long Range ◽  
Wind Waves ◽  
The United States ◽  
Ship Routing ◽  
Waves And Currents

The paper describes the system developed and used by the United States Hydrographic Office for selecting the optimum track for transoceanic crossings by applying long-range predictions of wind, waves and currents to a knowledge of how the routed vessel reacts to these variables. Over a period of two years, over 1000 optimum ship routes were provided to one authority, with an average reduction in travel time of 14 hours.

scholarly journals COMPARISON OF BASIC MAINTENANCE CONCEPTS USING WITNESS

2021 ◽  
Vol 2021 (6) ◽  
pp. 5435-5440
Author(s):  
VLADIMIRA SCHINDLEROVA ◽  
◽  
IVANA SAJDLEROVA ◽  
Keyword(s):  
21St Century ◽  
Simulation Software ◽  
Predictive Maintenance ◽  
Maintenance Management ◽  
Practical Application ◽  
Manufactured Products ◽  
The Right ◽  
Positive Effect ◽  
Production Facilities

Maintenance is a complex, extensive and important issue in terms of its impact on the quality of manufactured products or services provided in all areas of industry. The importance of predictive maintenance for the industry in the 21st century is crucial. However, the right approach to maintenance management is often underestimated in many companies today, although it can have a very positive effect on the company’s efficiency. Using the example of a practical application, the paper includes a comparison of three main maintenance concepts – classical (reactive), planned, predictive through the simulation software Witness. Maintenance concepts are compared in terms of their ability to solve and eliminate failures that occur in production facilities during operation.

Effect of Short-Term Weather Predictions on Model Predictive Trajectory Tracking Performance of Unmanned Surface Vessels

2020 ◽  
Author(s):  
Benjamin Armentor ◽  
Joseph Stevens ◽  
Nathan Madsen ◽  
Andrew Durand ◽  
Joshua Vaughan
Keyword(s):  
Trajectory Tracking ◽  
Wind Waves ◽  
Tracking Error ◽  
Tracking Performance ◽  
Model Predictive Controller ◽  
Prediction Horizon ◽  
Surface Vessels ◽  
Waves And Currents ◽  
Predictive Controller ◽  
Disturbance Model

Abstract For mobile robots, such as Autonomous Surface Vessels (ASVs), limiting error from a target trajectory is necessary for effective and safe operation. This can be difficult when subjected to environmental disturbances like wind, waves, and currents. This work compares the tracking performance of an ASV using a Model Predictive Controller that includes a model of these disturbances. Two disturbance models are compared. One prediction model assumes the current disturbance measurements are constant over the entire prediction horizon. The other uses a statistical model of the disturbances over the prediction horizon. The Model Predictive Controller performance is also compared to a PI-controlled system under the same disturbance conditions. Including a disturbance model in the prediction of the dynamics decreases the trajectory tracking error over the entire disturbance spectrum, especially for longer horizon lengths.

Clustering Applied to Large Sets of Environmental Conditions for Selecting Typical Scenarios for Ship Maneuvering Real-Time Simulations

2021 ◽  
Author(s):  
Felipe M. Moreno ◽  
Eduardo A. Tannuri
Keyword(s):  
Time Series ◽  
Cluster Analysis ◽  
Environmental Conditions ◽  
Wind Waves ◽  
Fast Time ◽  
Large Set ◽  
Ship Maneuvering ◽  
Partitioning Around Medoids ◽  
Waves And Currents ◽  
Maneuvering Simulations

Abstract The methodology described in this paper is used to reduce a large set of combined wind, waves, and currents to a smaller set that still represents well enough the desired site for ship maneuvering simulations. This is achieved by running fast-time simulations for the entire set of environmental conditions and recording the vessel’s drifting time-series while it is controlled by an automatic-pilot based on a line-of-sight algorithm. The cases are then grouped considering how similar the vessel’s drifting time-series are, and one environmental condition is selected to represent each group found by the cluster analysis. The measurement of dissimilarity between the time-series is made by application of Dynamic Time Warping and the Cluster Analysis is made by the combination of Partitioning Around Medoids algorithm and the Silhouette Method. Validation is made by maneuvering simulations made with a Second Deck Officer.

Experimental and Numerical Study of the Cutting Temperature during the Turning of the C45 Steel

2016 ◽  
Vol 823 ◽  
pp. 507-512
Author(s):  
Mourad Abdelkrim ◽  
Mourad Brioua ◽  
Abderrahim Belloufi ◽  
Abdelhafid Gherfi
Keyword(s):  
Numerical Study ◽  
Digital Simulation ◽  
Cutting Temperature ◽  
Medium Carbon Steel ◽  
Simulation Software ◽  
Interface Temperature ◽  
Work Piece ◽  
Turning Process

In machining operation, the quality of surface finish is an important requirement for many turned work pieces. cutting temperature is one of the most important parameters in determining the cutting performance and tool life. the objective for this work is to estimate the cutting temperature in 3D model on tool-chip interface and the interface temperature during turning process, using the digital simulation software COMSOL Multiphysics.The tool–chip interface temperature results obtained from experimental results by using C45 medium carbon steel work piece with natural contact tools, without the application of cooling and lubricating agents and a K type thermocouple technique was used for estimating cutting temperatures in a turning operation.This procedure facilitates the determination of the temperature at tool-chip interface in dry turning process, which is still a challenge for existing experimental and numerical methods.

Applied Research of Frequency Discriminator Based on LabVIEW

2014 ◽  
Vol 910 ◽  
pp. 323-326
Author(s):  
Shu Lai Liang ◽  
Zhao Peng Li ◽  
Zhou Guo Hou
Keyword(s):  
Virtual Instrument ◽  
High Frequency ◽  
Applied Research ◽  
Simulation Experiment ◽  
Virtual Machines ◽  
Virtual Experiment ◽  
Development Platform ◽  
Frequency Discriminator

This article through introduction tradition high frequency laboratory existence shortcoming and malpractice , Proposed the idea of Virtual instrument made for high-frequency laboratory ,then introduced the characteristic of LabVIEW (a development platform for virtual experiment),And proved the feasibility of using virtual machines have the discriminator through the simulation experiment .

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