scholarly journals A COLREGs-Based Dynamic Navigation Safety Domain for Unmanned Surface Vehicles: A Case Study of Dolphin-I

2020 ◽  
Vol 8 (4) ◽  
pp. 264
Author(s):  
Jian Zhou ◽  
Chenxu Wang ◽  
Anmin Zhang
Keyword(s):  
Collision Avoidance ◽  
Domain Boundary ◽  
Specific Model ◽  
Unmanned Surface Vehicles ◽  
Intelligent Machines ◽  
Dynamic Navigation ◽  
International Regulations ◽  
Domain Models ◽  
Navigation Safety

Unmanned Surface Vehicles (USVs) are intelligent machines that have been widely studied in recent years. The safety of USVs’ activities is a priority issue in their applications; one effective method is to delimit an exclusive safety domain around the USV. Besides considering collision avoidance, the safety domain should satisfy the requirements of encounter situations in the COLREGs (International Regulations for Preventing Collisions at Sea) as well. Whereas the model providing the safety domain for the USVs is defined through the experience of the manned ships, a specific model for USVs has been rarely studied. A dynamic navigation safety domain (DNSD) for USVs was proposed in this paper. To construct the model, the essential factors that could affect the navigation safety of the USVs were extracted via a rough set, and the extension functions of these factors were carried out. The DNSD was employed in various situations and compared with the ship domain models of common ships. It was found that the domain boundary can be automatically corrected according to the change in the working conditions when the DNSD is in use. Compared with the Fujii and Coldwell models, the DNSD can provide a larger safety area for a USV’s action of collision avoidance.

scholarly journals Artificial potential field-based swarm finding of the unmanned surface vehicles in the dynamic ocean environment

2020 ◽  
Vol 17 (3) ◽  
pp. 172988142092530
Author(s):  
Guoge Tan ◽  
Jiayuan Zhuang ◽  
Jin Zou ◽  
Lei Wan ◽  
Zhiyuan Sun
Keyword(s):  
Numerical Simulations ◽  
Collision Avoidance ◽  
Potential Field ◽  
Advanced Technology ◽  
Artificial Potential Field ◽  
Unmanned Surface Vehicle ◽  
Unmanned Surface Vehicles ◽  
Field Force ◽  
International Regulations ◽  
Ocean Environment

Using multiple unmanned surface vehicle swarms to implement tasks cooperatively is the most advanced technology in recent years. However, how to find which swarm the unmanned surface vehicle belongs to is a meaningful job. So, this article proposed an artificial potential field-based swarm finding algorithm, which applies the potential field force directly to unmanned surface vehicles and leads them to their belonging swarm quickly and accurately. Meanwhile, the proposed algorithm can also maintain the formation stable while following the desired path. Based on the swarm finding algorithm, the artificial potential field-based collision avoidance method and the International Regulations for Preventing Collisions at Sea-based dynamic collision avoidance strategy are applied to the swarm control of multi-unmanned surface vehicles to enhance the performance in the dynamic ocean environment. Methods in this article are verified through numerical simulations to illustrate the feasibility and effectiveness of proposed schemes.

scholarly journals Collision Avoidance Algorithm Based on COLREGs for Unmanned Surface Vehicle

2021 ◽  
Vol 9 (8) ◽  
pp. 863
Author(s):  
Hyo-Gon Kim ◽  
Sung-Jo Yun ◽  
Young-Ho Choi ◽  
Jae-Kwan Ryu ◽  
Jin-Ho Suh
Keyword(s):  
Collision Avoidance ◽  
Unmanned Surface Vehicle ◽  
Unmanned Surface Vehicles ◽  
International Regulations ◽  
Window Approach

Recently, unmanned surface vehicles (USV) are being actively developed. For USVs to be put to practical use, it is necessary to secure safety by preventing collisions with general ships. To this end, USVs must avoid opposing vessels based on international regulations for preventing collisions at sea (COLREGs, 1972). This paper proposes an algorithm for USVs to avoid collisions with opposing vessels based on COLREG rules. The proposed algorithm predicts dangerous situations based on distance to closest point of approach (DCPA) and time to closest point of approach (TCPA). It allows USVs to avoid opponent ships based on the dynamic window approach (DWA). The DWA has been improved to comply with COLREGs, and we implemented a simulation and compared the standard DWA with the COLREG-compliant DWA (CCDWA) proposed in this paper. The results confirm that the CCDWA complies with COLREGs.

scholarly journals Collision avoidance planning for unmanned surface vehicle based on eccentric expansion

2019 ◽  
Vol 16 (3) ◽  
pp. 172988141985194 ◽  
Author(s):  
Lifei Song ◽  
Zhuo Chen ◽  
Zaopeng Dong ◽  
Zuquan Xiang ◽  
Yunsheng Mao ◽  
...  
Keyword(s):  
Collision Avoidance ◽  
Obstacle Avoidance ◽  
Physical Simulation ◽  
Risk Level ◽  
Unmanned Surface Vehicle ◽  
Unmanned Surface Vehicles ◽  
Automatic Driving ◽  
International Regulations ◽  
Dynamic Obstacle Avoidance ◽  
Dynamic Obstacle

The International Regulations for Preventing Collisions at Sea (COLREGS) specify certain navigation rules for ships at risk for collision. Theoretically, the safety of unmanned surface vehicles and traffic boats would be guaranteed when they comply with the COLREGS. However, if traffic boats do not comply with the demands of the convention, thereby increasing the danger level, then adhering to the COLREGS may be dangerous for the unmanned surface vehicle. In this article, a dynamic obstacle avoidance algorithm for unmanned surface vehicles based on eccentric expansion was developed. This algorithm is used to solve the possible failure of collision avoidance when the unmanned surface vehicle invariably obeys the COLREGS during the avoidance process. An obstacle avoidance model based on the velocity obstacle method was established. Thereafter, an eccentric expansion operation on traffic boats was proposed to ensure a reasonable balance between safety and the rules of COLREGS. The expansion parameters were set according to the rules of COLREGS and the risk level of collision. Then, the collision avoidance parameters were calculated based on the aforementioned motion model. With the use of MATLAB and Unity software, a semi-physical simulation platform was established to perform the avoidance simulation experiment under different situations. Results show the validity, reliability and intellectuality of the algorithm. This research can be used for intelligent collision avoidance of unmanned surface vehicle and other automatic driving ships.

scholarly journals Vessel Multi-Parametric Collision Avoidance Decision Model: Fuzzy Approach

2021 ◽  
Vol 9 (1) ◽  
pp. 49
Author(s):  
Tanja Brcko ◽  
Andrej Androjna ◽  
Jure Srše ◽  
Renata Boć
Keyword(s):  
Fuzzy Logic ◽  
Collision Avoidance ◽  
Decision Model ◽  
Fuzzy Inference ◽  
Weather Conditions ◽  
Target Vessel ◽  
Planning Tool ◽  
Inference System ◽  
International Regulations ◽  
Input Variables

The application of fuzzy logic is an effective approach to a variety of circumstances, including solutions to maritime anti-collision problems. The article presents an upgrade of the radar navigation system, in particular, its collision avoidance planning tool, using a decision model that combines dynamic parameters into one decision—the collision avoidance course. In this paper, a multi-parametric decision model based on fuzzy logic is proposed. The model calculates course alteration in a collision avoidance situation. First, the model collects input data of the target vessel and assesses the collision risk. Using time delay, four parameters are calculated for further processing as input variables for a fuzzy inference system. Then, the fuzzy logic method is used to calculate the course alteration, which considers the vessel’s safety domain and International Regulations for Preventing Collisions at Sea (COLREGs). The special feature of the decision model is its tuning with the results of the database of correct solutions obtained with the manual radar plotting method. The validation was carried out with six selected cases simulating encounters with the target vessel in the open sea from different angles and at any visibility. The results of the case studies have shown that the decision model computes well in situations where the own vessel is in a give-way position. In addition, the model provides good results in situations when the target vessel violates COLREG rules. The collision avoidance planning tool can be automated and serve as a basis for further implementation of a model that considers the manoeuvrability of the vessels, weather conditions, and multi-vessel encounter situations.

scholarly journals Path Planning for Autonomous Ships: A Hybrid Approach Based on Improved APF and Modified VO Methods

2021 ◽  
Vol 9 (7) ◽  
pp. 761
Author(s):  
Liang Zhang ◽  
Junmin Mou ◽  
Pengfei Chen ◽  
Mengxia Li
Keyword(s):  
Path Planning ◽  
Local Minimum ◽  
Hybrid Approach ◽  
Artificial Potential Field ◽  
Whole Process ◽  
International Regulations ◽  
Local Path ◽  
Velocity Obstacle ◽  
Global And Local

In this research, a hybrid approach for path planning of autonomous ships that generates both global and local paths, respectively, is proposed. The global path is obtained via an improved artificial potential field (APF) method, which makes up for the shortcoming that the typical APF method easily falls into a local minimum. A modified velocity obstacle (VO) method that incorporates the closest point of approach (CPA) model and the International Regulations for Preventing Collisions at Sea (COLREGS), based on the typical VO method, can be used to get the local path. The contribution of this research is two-fold: (1) improvement of the typical APF and VO methods, making up for previous shortcomings, and integrated COLREGS rules and good seamanship, making the paths obtained more in line with navigation practice; (2) the research included global and local path planning, considering both the safety and maneuverability of the ship in the process of avoiding collision, and studied the whole process of avoiding collision in a relatively entirely way. A case study was then conducted to test the proposed approach in different situations. The results indicate that the proposed approach can find both global and local paths to avoid the target ship.

Automatic identification system data-driven model for analysis of ship domain near bridge-waters

2021 ◽  
pp. 1-22
Author(s):  
Lei Jinyu ◽  
Liu Lei ◽  
Chu Xiumin ◽  
He Wei ◽  
Liu Xinglong ◽  
...  
Keyword(s):  
Least Squares Method ◽  
Automatic Identification ◽  
Identification System ◽  
Collision Risk ◽  
Automatic Identification System ◽  
Domain Models ◽  
System Data ◽  
Quantification Model ◽  
Highly Correlated

Abstract The ship safety domain plays a significant role in collision risk assessment. However, few studies take the practical considerations of implementing this method in the vicinity of bridge-waters into account. Therefore, historical automatic identification system data is utilised to construct and analyse ship domains considering ship–ship and ship–bridge collisions. A method for determining the closest boundary is proposed, and the boundary of the ship domain is fitted by the least squares method. The ship domains near bridge-waters are constructed as ellipse models, the characteristics of which are discussed. Novel fuzzy quaternion ship domain models are established respectively for inland ships and bridge piers, which would assist in the construction of a risk quantification model and the calculation of a grid ship collision index. A case study is carried out on the multi-bridge waterway of the Yangtze River in Wuhan, China. The results show that the size of the ship domain is highly correlated with the ship's speed and length, and analysis of collision risk can reflect the real situation near bridge-waters, which is helpful to demonstrate the application of the ship domain in quantifying the collision risk and to characterise the collision risk distribution near bridge-waters.

scholarly journals Navigation safety domain and collision risk index for decision support of collision avoidance of USVs

2021 ◽  
Vol 13 ◽  
pp. 340-350
Author(s):  
Jian Zhou ◽  
Feng Ding ◽  
Jiaxuan Yang ◽  
Zhengqiang Pei ◽  
Chenxu Wang ◽  
...  
Keyword(s):  
Decision Support ◽  
Collision Avoidance ◽  
Risk Index ◽  
Collision Risk ◽  
Navigation Safety

scholarly journals Research on determination method of the true visibility on vessels based on radar and light intensity chart of the lighthouse

2021 ◽  
pp. 132-136
Author(s):  
Т.З. Нгуен
Keyword(s):  
Light Intensity ◽  
Collision Avoidance ◽  
Safety Management ◽  
Weather Condition ◽  
Management Systems ◽  
Determination Method ◽  
Safety Management Systems ◽  
Is Research ◽  
Visibility Condition ◽  
International Regulations

Определение истинной видимости является основной морской метеорологической операцией дежурного офицера на борту. В условиях ограниченной видимости суда должны работать в соответствии с Правилом 19 Международных правил предотвращения столкновений на море. Однако в настоящее время нет документов, которые бы четко и количественно давались в руководстве по определению видимости на море. С другой стороны, системы управления безопасностью некоторых судоходных компаний выдают предупреждения, и дежурный офицер должен уведомить или вызвать капитана, когда видимость упадет до определенного предела. Это затрудняет для дежурного офицера принятие независимого решения об избежании столкновения в случае ухудшения видимости. В целях содействия решению актуальной морской проблемы, о которой говорилось выше, целью данной работы является исследование метода определения видимости на борту судна в определенных погодных условиях. Determining the true visibility is a basic marine meteorological operation of the duty officer on board. In the restricted visibility condition, vessels must sailing in accordance with Rule 19, International regulations for preventing collisions at sea. However, there are currently no documents that given clearly and quantitative in the guidance for determining visibility at sea. Otherwise, the warnings in the safety management systems of some shipping companies were given, and the officer of watch must inform or call the captain when the visibility reduced to a certain limit. This makes it difficult for the officer of watch to give the independent collision avoidance decision in the event of reduced visibility. In order to contribute to solve the actual maritime problem which is mentioned above, the goal of the paper is research on determine method of the visibility on board in a certain weather condition.

Decision-making of investment in navigation safety improving schemes with application of cumulative prospect theory

2018 ◽  
Vol 232 (6) ◽  
pp. 710-724 ◽  
Author(s):  
Lei Wang ◽  
Qing Liu ◽  
Tongle Yin
Keyword(s):  
Decision Making ◽  
Prospect Theory ◽  
Investment Decision ◽  
Cumulative Prospect Theory ◽  
Decision Makers ◽  
Investment Decision Making ◽  
Risk Appetite ◽  
Safety Investment ◽  
Navigation Safety

Navigation safety improving investment aims at mitigating risk and improving safety of shipping system, while decision-makers’ attitudes toward the uncertainty of shipping safety possess a characteristic of “bounded rationality.” To study the tendency of shipping safety investment decision-making with different risk perception and appetite, a decision-making method based on cumulative prospect theory is proposed in this article. First, we extract the decision attributes through analyzing the factors affecting shipping safety investment. Then, according to cumulative prospect theory, the value function and the probability weighting function for calculating cumulative prospect values of shipping investment attributes are given. Under the risk-based multi-attribute group decision-making framework, linear programming model and projection method are introduced to aggregate the weights of attributes and decision-makers, respectively. Furthermore, through a case study, the proposed methodology is utilized in Three Gorges Dam area, and the desirable safety investment scheme is determined from a set of candidate alternatives. The case study shows not only validity and feasibility of the decision-making approach but also the mechanism of shipping safety investment decision-making with consideration of the behavior characteristics of decision-makers such as reference dependence, risk appetite distortion, and loss aversion.

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