CN117111606B - Ship auxiliary collision prevention method and system - Google Patents

Abstract

The invention discloses a ship auxiliary collision prevention method and a system, wherein the method comprises the following steps: acquiring self information and current environment information of the ship, wherein the current environment information comprises wind speed and tide speed; determining a first navigation path by adopting a first path planning strategy based on self information and current environment information of the ship; based on an AIS receiver and an ECDIS subsystem, when detecting that collision risk exists in a first time threshold under the first navigation path, starting the radar subsystem, and adopting a second path planning strategy; and based on the radar subsystem and the ECDIS subsystem, when detecting that collision risk exists in a second time threshold under the first navigation path, adopting a third path rule strategy. According to different scenes, the invention combines the functions and data of different equipment to make more reasonable sailing decisions, thereby ensuring the safety of crews and ships and improving the safety and efficiency of sailing.

Description

Ship auxiliary collision prevention method and system

Technical Field

The invention belongs to the field of ship situation awareness, and particularly relates to a ship auxiliary collision prevention method and system.

Background

Marine transportation occupies a significant position in world trade, and the development of world economy has also led to an increase in the traffic flow density of certain channels or important navigable areas year by year. The large traffic density and the development trend of the large and high-speed ships improve the transportation efficiency and reduce the safety at the same time, so that the frequent occurrence of water traffic accidents is caused. And the most frequent and harmful modal ship collisions occur in various water areas. Collisions often cause significant casualties, ship and cargo losses, sometimes accompanied by environmental hazards such as spills. The collision accident of the ship mostly occurs in ports, narrow waterways, waterway intersections, fishing areas and low visibility areas. These areas are dense, frequent, complex, and poor in navigation and natural environment. The sailing situation of the ship refers to the actual motion trend and state of the ship, which are formed by the influence of various internal and external factors, and the subsequent possible changes.

Because of the complexity of the surrounding environment of the ship, in practical operation, the relative motion trend is often used to describe the relative motion relationship between the ship and various objects such as other ships, wharfs, facilities, obstacles, etc., and the relationship is called a meeting situation in navigation. The meeting situation comprises an meeting situation in the mutual meeting and an meeting situation when the visibility is poor, the judgment of the meeting situation is an important basis for a driver to determine applicable 1972 International maritime collision avoidance rules so as to determine avoidance responsibility of the ship and actions to be taken, and is also an important component part of the ship avoidance decision, and maritime practice shows that insufficient knowledge of the meeting situation is one of important reasons for causing uncoordinated collision avoidance actions among the ships or even collision. In the ship navigation process, the meeting situation of the current channel and all other ships in a certain range in front is called a ship navigation situation, so that the analysis and research of the ship navigation situation are significant for ship navigation safety and route planning. The research of the intelligent ship collision avoidance system in China starts later. According to the data, the research of the ship collision avoidance expert system is started by universities and colleges such as universities of Dai maritime universities, naval Dai water surface naval academy and scientific research institutions at the beginning of the 90 th century. The ship collision avoidance expert system studied by naval Guangzhou naval academy is also a consultative collision avoidance expert system, and has fewer considered factors and coarser division of meeting situations. Later, domestic scholars also put forward the ship collision avoidance system based on a plurality of intelligent algorithms successively, but the precision and the accuracy are lower, and the practicality is not high, especially the influence of ocean currents on ships.

Therefore, the method is more accurate, more reliable and higher in information comprehensive degree, and the collision prevention and early warning modes of the ship under navigation are necessary.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a ship auxiliary collision prevention method, which comprises the following steps:

Step S101, acquiring self information and current environment information of the ship, wherein the current environment information comprises wind speed and tide speed;

Step S102, determining a first navigation path by adopting a first path planning strategy based on self information and current environment information of the ship;

Step S103, starting a radar subsystem and adopting a second path planning strategy when detecting that collision risk exists in a first time threshold under the first navigation path based on an AIS receiver and an ECDIS subsystem;

Step S104, based on the radar subsystem and the ECDIS subsystem, when detecting that collision risk exists in a second time threshold under the first navigation path, adopting a third path rule strategy;

step S105, after successful avoidance, step S101 is executed again.

The ship information comprises course, speed, draft, current course point coordinates and target course point coordinates.

Wherein the first path rule adopts a dynamic programming algorithm.

The first path rule adopts a dynamic programming algorithm, and specifically comprises the following steps:

Step S1031, assuming that there are N waypoints, the longitude of the ith waypoint is L _i, the latitude is B _i, the distance from the ith waypoint to the jth waypoint is D _ij (i, j=1, 2,.., N), and the state variable f (i, v, θ) represents the shortest time from the starting point to the ith waypoint at the navigational speed v and the heading θ, wherein v and θ represent the navigational speed and the heading of the ship, respectively;

Step S1032, according to the physical model of ship navigation and the thought of dynamic planning, a state transition equation can be obtained:

f (i, V, θ) =min { f (k, V, θ) +d _ik/V (V, θ, D, w, u) }, where k=1, 2,..;

Wherein V (V, theta, D, w, u) represents the speed of the ship at the speed V, the heading theta, the draft D, the wind speed w and the tidal current speed u, and D _ik represents the distance from the ith waypoint to the kth waypoint;

Step S1033, at the starting point, the ship speed is v ₀, the heading is θ ₀, and the initial state can be set as follows:

f(1,v₀,θ₀)＝0；

In step S1034, when the ship reaches the end point, the state variable reaches the final state, and the end state may be defined as:

min { f (N, v, θ) }, where v and θ represent the speed and heading of the vessel;

in step S1035, in the state transition equation, the decision variables are the speed and heading of the ship.

The step S1032 specifically includes:

based on state transition equation f (i, V, θ) =min { f (k, V, θ) +d _ik/V (V, θ, D, w, u) }, where k=1, 2,..;

Then V (V, θ, d, w, u) =v ₀+K_T-K_W–K_U;

Wherein V ₀ is the maximum navigational speed of the ship in still water, K _T is the rudder angle influence coefficient, K _W is the wind force influence coefficient, K _U is the tide influence coefficient, and K _T、K_W、K_U is converted into the same unit as navigational speed;

according to the physical model of the ship, the motion equation of the ship can be obtained:

dx/dt＝V(v,θ,d,w,u)*cos(θ)；

dy/dt＝V(v,θ,d,w,u)*sin(θ)；

wherein dx/dt and dy/dt represent the speed of the ship on the x-axis and the y-axis, respectively, cos (θ) and sin (θ) represent the x-and y-direction components of the ship's heading, respectively;

the distance from the ith waypoint to the kth waypoint may be expressed as:

D_ik＝sqrt(x_k–x_i)²+(y_k–y_i)²)；

Wherein x _i and y _i are the longitude and latitude, respectively, of the ith waypoint, and x _k and y _k are the longitude and latitude, respectively, of the kth waypoint;

finally, the state transition equation is expressed as follows:

f(i,v,θ)＝min{f(k,v,θ)+sqrt(x_k–x_i)²+(y_k–y_i)²)/(V₀+K_T-K_W–K_U)};

where k=1, 2.

And determining the ship navigational speed and the ship navigational course which minimize the state variable by adopting an enumeration method or a search method.

Wherein the first time threshold is greater than the second time threshold.

Wherein the second path planning strategy comprises: when the ship sails in the downwind direction, a reminding signal is sent to the opposite-end ship.

Wherein the third path rule policy includes: actively changing the own speed or heading of the ship.

The invention also provides a ship auxiliary collision avoidance system, which comprises:

the acquisition module is used for acquiring self information of the ship and current environment information, wherein the current environment information comprises wind speed and tide speed;

the path determining module is used for determining a first navigation path by adopting a first path planning strategy based on the self information and the current environment information of the ship;

The first early warning module is used for starting the radar subsystem and adopting a second path planning strategy when detecting that collision risk exists in a first time threshold under the first navigation path based on the AIS receiver and the ECDIS subsystem;

And the second early warning module is used for adopting a third path rule strategy when detecting that collision risk exists in a second time threshold under the first navigation path based on the radar subsystem and the ECDIS subsystem.

Compared with the prior art, the dynamic programming equation for generating the optimal route based on the current position, the target position, the speed, the heading, the draft, the wind speed and the tide of the ship can be established through the elements such as state variables, state transition equations, initial states, ending states, decision variables and the like. In practical application, the invention can also make more reasonable sailing decisions according to different scenes and by combining the functions and data of different devices, thereby ensuring the safety of crews and ships and improving the safety and efficiency of sailing.

Drawings

The above, as well as additional purposes, features, and advantages of exemplary embodiments of the present disclosure will become readily apparent from the following detailed description when read in conjunction with the accompanying drawings. Several embodiments of the present disclosure are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar or corresponding parts and in which:

Fig. 1 is a flowchart showing a ship auxiliary collision avoidance method according to an embodiment of the present invention;

fig. 2 is a schematic view showing a ship auxiliary collision avoidance system according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, the "plurality" generally includes at least two.

It should be understood that although the terms first, second, third, etc. may be used in describing … … in embodiments of the present invention, these … … should not be limited to these terms. These terms are only used to distinguish … …. For example, the first … … may also be referred to as the second … …, and similarly the second … … may also be referred to as the first … …, without departing from the scope of embodiments of the present invention.

It should be understood that the term "and/or" as used herein is merely one relationship describing the association of the associated objects, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrase "if determined" or "if detected (stated condition or event)" may be interpreted as "when determined" or "in response to determination" or "when detected (stated condition or event)" or "in response to detection (stated condition or event), depending on the context.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such product or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a commodity or device comprising such elements.

Alternative embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Embodiment 1,

As shown in fig. 1, the invention discloses a ship auxiliary collision prevention method, which comprises the following steps:

Step S101, acquiring self information and current environment information of the ship, wherein the current environment information comprises wind speed and tide speed;

Step S102, determining a first navigation path by adopting a first path planning strategy based on self information and current environment information of the ship;

Step S103, starting a radar subsystem and adopting a second path planning strategy when detecting that collision risk exists in a first time threshold under the first navigation path based on an AIS receiver and an ECDIS subsystem;

Step S104, based on the radar subsystem and the ECDIS subsystem, when detecting that collision risk exists in a second time threshold under the first navigation path, adopting a third path rule strategy;

step S105, after successful avoidance, step S101 is executed again.

The ship information comprises course, speed, draft, current course point coordinates and target course point coordinates.

Wherein the first path rule adopts a dynamic programming algorithm.

The first path rule adopts a dynamic programming algorithm, and specifically comprises the following steps:

Step S1031, assuming that there are N waypoints, the longitude of the ith waypoint is L _i, the latitude is B _i, the distance from the ith waypoint to the jth waypoint is D _ij (i, j=1, 2,.., N), and the state variable f (i, v, θ) represents the shortest time from the starting point to the ith waypoint at the navigational speed v and the heading θ, wherein v and θ represent the navigational speed and the heading of the ship, respectively;

Step S1032, according to the physical model of ship navigation and the thought of dynamic planning, a state transition equation can be obtained:

f (i, V, θ) =min { f (k, V, θ) +d _ik/V (V, θ, D, w, u) }, where k=1, 2,..;

Wherein V (V, theta, D, w, u) represents the speed of the ship at the speed V, the heading theta, the draft D, the wind speed w and the tidal current speed u, and D _ik represents the distance from the ith waypoint to the kth waypoint;

Step S1033, at the starting point, the ship speed is v ₀, the heading is θ ₀, and the initial state can be set as follows:

f(1,v₀,θ₀)＝0；

In step S1034, when the ship reaches the end point, the state variable reaches the final state, and the end state may be defined as:

min { f (N, v, θ) }, where v and θ represent the speed and heading of the vessel;

in step S1035, in the state transition equation, the decision variables are the speed and heading of the ship.

The step S1032 specifically includes:

based on state transition equation f (i, V, θ) =min { f (k, V, θ) +d _ik/V (V, θ, D, w, u) }, where k=1, 2,..;

Then V (V, θ, d, w, u) =v ₀+K_T-K_W–K_U;

Wherein V ₀ is the maximum navigational speed of the ship in still water, the navigational speed unit is a section, K _T is a rudder angle influence coefficient, K _W is a wind force influence coefficient, K _U is a tide influence coefficient, K _T、K_W、K_U is a dimensionless ratio, and the navigational speed unit can be directly converted into the same unit as the navigational speed;

according to the physical model of the ship, the motion equation of the ship can be obtained:

dx/dt＝V(v,θ,d,w,u)*cos(θ)；

dy/dt＝V(v,θ,d,w,u)*sin(θ)；

wherein dx/dt and dy/dt represent the speed of the ship on the x-axis and the y-axis, respectively, cos (θ) and sin (θ) represent the x-and y-direction components of the ship's heading, respectively;

the distance from the ith waypoint to the kth waypoint may be expressed as:

D_ik＝sqrt(x_k–x_i)²+(y_k–y_i)²)；

Wherein x _i and y _i are the longitude and latitude, respectively, of the ith waypoint, and x _k and y _k are the longitude and latitude, respectively, of the kth waypoint;

finally, the state transition equation is expressed as follows:

f(i,v,θ)＝min{f(k,v,θ)+sqrt(x_k–x_i)²+(y_k–y_i)²)/(V₀+K_T-K_W–K_U)};

where k=1, 2.

In one embodiment, the wind influence coefficient K _W is calculated as follows:

K_W＝0.5*ρ*A_w*V_w ²*S^-1；

Wherein ρ is air density, A _w is wind load area, V _w is wind speed, and S is waterline area of the ship.

The rudder angle influence coefficient K _T is calculated as follows:

K_T＝(δ-δ₀)/δ_m

Wherein delta is the actual rudder angle, delta ₀ is the rudder angle when the rudder angle is zero, delta _m is the maximum rudder angle.

The calculation of the tidal current influence coefficient K _U is as follows:

K_U＝(V_c*cos(θ_c-θ_s))/V₀

Wherein V _c is the tide speed, theta _c is the tide direction, theta _s is the heading of the ship, and V ₀ is the maximum navigational speed of the ship in still water.

In practice, the calculation of K _T、K_W、K_U typically involves a variety of physical quantities and units. In order to convert them into units identical to the speed, a corresponding unit conversion is required. For example, in calculating the wind influence coefficient K _W, it is necessary to convert the unit of wind speed from meter/second or km/h to knots in order to maintain the same unit as the ship speed. Common unit conversions are as follows:

Wind speed: typically using meters per second or kilometers per hour as a unit, can be converted into knots by the following formula:

1 m/s approximately 1.944 knots;

1 km/h approximately 0.54 knots;

Area of wind load: typically using square meters as a unit, can be converted to square feet by the following formula:

1 square meter approximately 10.764 square feet;

tidal current speed: typically using meters per second or kilometers per hour as a unit, can be converted into knots by the following formula:

1 m/s approximately 1.944 knots;

1 km/h approximately 0.54 knots.

And determining the ship navigational speed and the ship navigational course which minimize the state variable by adopting an enumeration method or a search method.

Wherein the first time threshold is greater than the second time threshold.

Wherein the second path planning strategy comprises: when the ship sails in the downwind direction, a reminding signal is sent to the opposite-end ship.

Wherein the third path rule policy includes: actively changing the own speed or heading of the ship.

Embodiment II,

As shown in fig. 2, the present invention further provides a ship auxiliary collision avoidance system, including:

the acquisition module is used for acquiring self information of the ship and current environment information, wherein the current environment information comprises wind speed and tide speed;

the path determining module is used for determining a first navigation path by adopting a first path planning strategy based on the self information and the current environment information of the ship;

The first early warning module is used for starting the radar subsystem and adopting a second path planning strategy when detecting that collision risk exists in a first time threshold under the first navigation path based on the AIS receiver and the ECDIS subsystem;

And the second early warning module is used for adopting a third path rule strategy when detecting that collision risk exists in a second time threshold under the first navigation path based on the radar subsystem and the ECDIS subsystem.

Third embodiment,

The invention also provides a ship auxiliary collision avoidance system, which comprises:

AIS (Automatic Identification Subsystem ) receiver: the AIS receiver can automatically acquire the information of the position, the course, the speed, the ship name, the call sign, national of ship countries and the like of the ship, and broadcast the information to surrounding ships and shore stations so as to improve the accuracy of the identification and the position confirmation of the ship;

ARPA subsystem (Automatic Radar Plotting Aid, automatic radar mapping subsystem): the ARPA system can automatically track the information of the position, heading, speed and the like of the ship and display the information on a radar screen. The ARPA system may provide warnings and advice of the risk of ship collision to help the crew avoid the risk of collision;

ECDIS subsystem (Electronic CHART DISPLAY AND Information Subsystem ): the ECDIS system may display information of the position, heading, speed, etc. of the ship and information of the course, obstacles, water depth, tides, weather, etc. on the electronic chart. The ECDIS system can provide safety advice and warning for ship operation so as to help a shipman avoid risks such as collision, reef contact and the like;

Early warning Subsystem (EARLY WARNING Subsystem): the early warning system can predict and early warn risks such as collision, reef contact, stranding and the like according to information such as position, heading and speed of the ship, and provide early warning suggestions and measures to help a crew avoid risk events.

Wherein the AIS receiver can confirm whether collision risk exists in advance when the AIS receiver is far away from the ECDIS subsystem, the time of possible collision, namely the determination condition of the first time threshold value, can be pre-determined in advance based on the distance or the navigational speed.

Due to the influence of sea waves, radar waves are not easy to find ships below the water level, and the propagation distance is also influenced to a certain extent, so that the ARPA subsystem and the ECDIS subsystem are matched for use when the distance is relatively short, and the risk of collision between the ARPA subsystem and the ECDIS subsystem can be comprehensively judged by referring to the monitoring result of the AIS receiver at the same time, and the risk is a determination condition of a second time threshold.

The early warning subsystem is used for comprehensively considering the results of the three detection subsystems to judge, sending an alarm to the other side, reminding the crewman of the ship, or actively sending an active avoidance request to the control subsystem.

The AIS receiver may provide MMSI (marine mobile communication service identification code) numbers for the vessel, the radar system may provide the position and motion status of the vessel, and the ECDIS system may display the position and heading of the vessel on an electronic chart. These data may be used in combination to improve the accuracy of identification and location confirmation of surrounding vessels.

And the control subsystem controls the ship to actively avoid. The dynamic collision avoidance decision is adopted, a plurality of factors need to be considered, and the multi-layer perception neural network and the residual neural network are deep learning algorithms and can be used for processing nonlinear relations and high-dimensional data.

The following information is usually required to be obtained as input:

Ship position: including the present ship location and other ship locations;

Speed of: including the speed of the vessel and other vessel speeds;

environmental data: including marine current, weather, sea conditions, etc.;

navigation rules: the method comprises the international offshore collision avoidance rule and the special rule of the ship;

ship state: including the state of the ship and other ship states, such as the angle of attack of the bow, heading, etc

Communication data: including radar data, AIS data, etc.

Firstly, preprocessing and feature extraction are carried out on input data, wherein the operations comprise data normalization, feature selection, data dimension reduction and the like, so that the dimension and complexity of the input data are reduced.

There may be data quality inconsistencies, deletions, errors, etc. due to different navigation data sources. For example, radar data may be affected by weather, ocean waves, and the like, resulting in inaccurate or incomplete data. Therefore, quality assessment and preprocessing of different data sources is required to ensure reliability and consistency of the data.

Integrating data from different data sources requires solving the problems of data format, data type, data precision, etc. For example, GPS data and electronic chart data use different coordinate systems, and coordinate conversion and unification are required. Meanwhile, the problems of data conflict and overlapping are required to be solved, and repeated calculation and inconsistency of data are avoided.

The method specifically comprises the following steps: the normalization processing and coordinate alignment steps for the data of the AIS receiver, the radar subsystem, the ECDIS subsystem and the early warning subsystem are as follows:

(1) Normalization:

For the data of each system, normalization processing is performed according to the data range thereof. Common normalization methods are min-max normalization and Z-score normalization.

Min-max normalization: scaling the data to a range of 0 to 1 by the following formula:

X_new＝(X-X_min)/(X_max-X_min)

Where X is the raw data, x_new is the normalized data, and x_min and x_max are the minimum and maximum values of the raw data, respectively.

Z-score normalization: data were converted to a distribution with a mean of 0 and standard deviation of 1 by the following formula:

X_new＝(X-mean)/stddev；

where X is the raw data, x_new is the normalized data, mean is the mean of the raw data, and stddev is the standard deviation of the raw data.

(2) Alignment of coordinates:

And according to application requirements, carrying out coordinate alignment on data of different systems so as to ensure that the data are compared and fused under the same coordinate system.

The coordinate alignment can be performed according to the information of the position, the speed, the heading and the like of the ship, so that the data of each system are ensured to correspond to each other at the same time point and the same spatial position.

A position fusion algorithm or interpolation method may be used to align the data to ensure that the data are compared under the same reference coordinate system.

Secondly, training the preprocessed data by using a multi-layer perception neural network to learn a nonlinear relation between input data and collision avoidance decisions. Cross-validation and regularization techniques may be used in the training process to reduce overfitting and improve model generalization ability.

And thirdly, training the output of the multi-layer perception neural network by using the residual neural network so as to further improve the accuracy and the robustness of the model. The residual neural network can effectively solve the problems of gradient elimination and gradient explosion of the deep neural network.

And finally, applying the trained model to a real-time collision avoidance decision. According to the current ship position, speed, environmental data, navigation rules, ship states and communication data, input data are input into a model to obtain corresponding collision avoidance decisions, such as rudder angles and engine thrust, and the course and speed of the ship are adjusted to avoid collision with other ships.

Fifth embodiment (V),

The disclosed embodiments provide a non-transitory computer storage medium storing computer executable instructions that perform the method steps described in the embodiments above.

It should be noted that the computer readable medium described in the present disclosure may be a computer readable signal medium or a computer readable storage medium, or any combination of the two. The computer readable storage medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples of the computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this disclosure, a computer-readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. In the present disclosure, however, the computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, with the computer-readable program code embodied therein. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to: electrical wires, fiber optic cables, RF (radio frequency), and the like, or any suitable combination of the foregoing.

The computer readable medium may be contained in the electronic device; or may exist alone without being incorporated into the electronic device.

Computer program code for carrying out operations of the present disclosure may be written in one or more programming languages, including an object oriented programming language such as Java, smalltalk, C ++ and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of remote computers, the remote computer may be connected to the user's computer through any kind of network, including a local Area Network (AN) or a Wide Area Network (WAN), or may be connected to AN external computer (e.g., connected through the internet using AN internet service provider).

The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

The units involved in the embodiments of the present disclosure may be implemented by means of software, or may be implemented by means of hardware. Wherein the names of the units do not constitute a limitation of the units themselves in some cases.

The foregoing description of the preferred embodiments of the present invention has been presented for purposes of clarity and understanding, and is not intended to limit the invention to the particular embodiments disclosed, but is intended to cover all modifications, alternatives, and improvements within the spirit and scope of the invention as outlined by the appended claims.

Claims (5)

1. The ship auxiliary collision avoidance method is characterized by comprising the following steps of:

Step S101, acquiring self information and current environment information of the ship, wherein the current environment information comprises wind speed and tide speed;

Step S102, determining a first navigation path by adopting a first path planning strategy based on self information and current environment information of the ship;

Step S103, starting a radar subsystem and adopting a second path planning strategy when detecting that collision risk exists in a first time threshold under the first navigation path based on an AIS receiver and an ECDIS subsystem;

Step S104, based on the radar subsystem and the ECDIS subsystem, when detecting that collision risk exists in a second time threshold under the first navigation path, adopting a third path rule strategy;

Step S105, after successful avoidance, executing step S101 again;

the first path planning adopts a dynamic planning algorithm;

the first path planning adopts a dynamic planning algorithm, and specifically comprises the following steps:

Step S1031, assuming that there are N waypoints, the longitude of the ith waypoint is L _i, the latitude is B _i, the distance from the ith waypoint to the jth waypoint is D _ij, i, j=1, 2,..n, the state variable f (i, v, θ) represents the shortest time from the starting point to the ith waypoint at the navigational speed v, the heading θ, wherein v and θ represent the navigational speed and the heading of the ship, respectively;

step S1032, according to the physical model of ship navigation and the thought of dynamic planning, a state transition equation is obtained:

f (i, V, θ) =min { f (k, V, θ) +d _ik/V (V, θ, D, w, u) }, where k=1, 2,..;

Wherein V (V, theta, D, w, u) represents the speed of the ship at the speed V, the heading theta, the draft D, the wind speed w and the tidal current speed u, and D _ik represents the distance from the ith waypoint to the kth waypoint;

Step S1033, at the starting point, the ship speed is v ₀, the heading is theta ₀, and the initial state is set as follows:

f(1,v₀,θ₀) = 0；

step S1034, when the ship reaches the end point, the state variable reaches the final state, and the end state is defined as:

min { f (N, v, θ) }, where v and θ represent the speed and heading of the vessel;

step S1035, in a state transfer equation, the decision variables are the navigational speed and the navigational direction of the ship;

The step S1032 specifically includes:

Based on state transition equation f (i, V, θ) =min { f (k, V, θ) +d _ik/V (V, θ, D, w, u) }, where k=1, 2,..;

then V (V, θ, d, w, u) =v ₀ + K_T - K_W – K_U;

Wherein V ₀ is the maximum navigational speed of the ship in still water, K _T is the rudder angle influence coefficient, K _W is the wind force influence coefficient, K _U is the tide influence coefficient, and K _T、K_W、K_U is converted into the same unit as navigational speed;

according to the physical model of the ship, the motion equation of the ship is obtained:

dx/dt = V(v,θ,d,w,u) * cos(θ)；

dy/dt = V(v,θ,d,w,u) * sin(θ)；

wherein dx/dt and dy/dt represent the speed of the ship on the x-axis and the y-axis, respectively, cos (θ) and sin (θ) represent the x-and y-direction components of the ship's heading, respectively;

the distance from the ith waypoint to the kth waypoint is expressed as:

D_ik = sqrt(x_k – x_i)² + (y_k – y_i)²);

Wherein x _i and y _i are the longitude and latitude, respectively, of the ith waypoint, and x _k and y _k are the longitude and latitude, respectively, of the kth waypoint;

finally, the state transition equation is expressed as follows:

f(i,v,θ)= min{f(k,v,θ)+ sqrt(x_k – x_i)² + (y_k – y_i)²)/(V₀ + K_T - K_W – K_U)};

where k=1, 2,..n, N represents the total number of waypoints;

The second path planning strategy comprises: when the ship sails in the downwind direction, a reminding signal is sent to the opposite-end ship;

the third path rule policy includes: actively changing the own speed or heading of the ship.

2. The ship auxiliary collision avoidance method of claim 1, wherein the ship's own information comprises heading, speed, draft, current waypoint coordinates and target waypoint coordinates.

3. The ship auxiliary collision avoidance method of claim 1, wherein the ship speed and heading that minimize the state variable are determined using an enumeration method or a search method.

4. The marine vessel assisted collision avoidance method of claim 1, wherein said first time threshold is greater than a second time threshold.

5. A system using the ship auxiliary collision avoidance method as claimed in any one of claims 1 to 4, comprising:

the acquisition module is used for acquiring self information of the ship and current environment information, wherein the current environment information comprises wind speed and tide speed;

the path determining module is used for determining a first navigation path by adopting a first path planning strategy based on the self information and the current environment information of the ship;

The first early warning module is used for starting the radar subsystem and adopting a second path planning strategy when detecting that collision risk exists in a first time threshold under the first navigation path based on the AIS receiver and the ECDIS subsystem;

And the second early warning module is used for adopting a third path rule strategy when detecting that collision risk exists in a second time threshold under the first navigation path based on the radar subsystem and the ECDIS subsystem.