Collision risk calculation device

Abstract

To provide a collision risk calculation device capable of calculating a collision risk of a ship by a simple method.SOLUTION: The collision risk calculation device 20 includes a relative azimuth rate-of-change calculation unit 24 which calculates a relative azimuth rate-of-change which is a rate-of-change of a relative azimuth of another vessel with respect to an own vessel 1A based on an azimuth of the own vessel 1A and an azimuth of another vessel, and a collision risk calculation unit 26 which calculates a risk of collision between the own vessel 1A and another vessel based on the calculated relative azimuth rate-of-change.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for avoiding collisions between ships. [Background technology]

[0002] Patent Document 1 describes a technique for calculating the risk of collision between one ship and another ship. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-103443 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 requires the use of the course (direction), position, and speed (scalar quantity) of each of the own ship and the other ship to calculate the risk of collision between the own ship and the other ship, resulting in a large number of parameter types.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to provide a collision risk calculation device that can calculate the collision risk of ships using a simple method. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the collision risk calculation device of the present invention comprises a relative heading change rate calculation unit that calculates a relative heading change rate, which is the rate of change of the relative heading of the other ship relative to the own ship, based on the heading of the own ship and the heading of the other ship, and a collision risk calculation unit that calculates a collision risk between the own ship and the other ship based on the calculated relative heading change rate, and is characterized in that the collision risk calculation unit calculates the collision risk so that the smaller the absolute value of the relative heading change rate, the greater the collision risk. [Effects of the Invention]

[0007] According to the present invention, the collision risk of a ship can be calculated using a simple method. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram schematically illustrating a ship maneuvering control system including a collision risk calculation device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view schematically illustrating a collision between the vessel and another vessel in the first embodiment of the present invention. [Figure 3] FIG. 10 is a plan view schematically showing the relationship between the ship and other ships in a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0010] First Embodiment 1, a ship (host ship) 1A according to a first embodiment of the present invention is equipped with a ship maneuvering control system 2 as a system for performing automatic ship maneuvering. The ship maneuvering control system 2 is equipped with an automatic ship identification system 11, a sea area information display device 12, a positioning device 13, a direction sensor 14, and a speed sensor 15.

[0011] The ship maneuvering control system 2 also includes a ship maneuvering control device 20, a notification device 31, a power unit 32 that is the power source of the ship 1A, and a steering device 33 for changing the direction of travel of the ship 1A. The notification device 31 is composed of a monitor that can display the collision risk R calculated by the ship maneuvering control device 20, a speaker that can output sound (or audio), etc. The monitor that serves as the notification device 31 can be shared with the monitor of the sea area information display device 12.

[0012] <Automatic Identification System> The Automatic Identification System (AIS) 11 is a device that automatically identifies other ships (other ships 1B, see Figure 2) sailing around the ship 1A and acquires the position and speed (direction and speed) of the identified other ships 1B from the AIS server. The Automatic Identification System 11 transmits the acquired results to the ship steering control device 20.

[0013] <Ocean area information display device> The sea area information display device 12 is a device that displays nautical charts (for example, navigational charts issued by the Japan Coast Guard) and reference charts (for example, electronic navigational reference charts, Y charts, etc.) of the sea area in which the ship is navigating. The sea area information display device 12 transmits information about the sea area in which the ship is navigating (information about topography, water depth, buoys, routes, other obstacles, tidal currents, etc.) to the ship maneuvering control device 20.

[0014] <Positioning device> The positioning device 13 is a device that uses the Global Navigation Satellite System (GNSS) to measure the position information (latitude and longitude) of the ship 1A. The positioning device 13 transmits the positioning result to the ship steering control device 20.

[0015] <Orientation sensor> The direction sensor 14 is a sensor that detects the direction (azimuth, course) of the ship 1 A. The direction sensor 14 transmits the detection result to the ship steering control device 20.

[0016] <Speed ​​sensor> The speed sensor 15 is a sensor that detects the speed (scalar quantity) of the ship 1 A. The speed sensor 15 transmits the detection result to the ship maneuvering control device 20.

[0017] <Ship steering control device (collision risk calculation device)> The ship maneuvering control device 20 generates a route and controls the power unit 32 and steering unit 33 to navigate the generated route. The ship maneuvering control device 20 transmits the positioning results of the positioning device 13 and the detection results of the direction sensor 14 and speed sensor 15 to the AIS server as information about the ship 1A. The ship maneuvering control device 20 also functions as a collision risk calculation device that calculates the collision risk R between the ship 1A and another ship 1B. The ship maneuvering control device 20 is composed of a CPU (Central Processing Unit), ROM (Read-Only Memory), RAM (Random Access Memory), input / output circuits, etc. The ship maneuvering control device 20 includes, as functional units, a memory unit 21, a ship information acquisition unit 22, an other ship information acquisition unit 23, a relative heading change speed calculation unit 24, a distance calculation unit 25, a collision risk calculation unit 26, a route generation unit 27, and a ship steering unit 28.

[0018] ≪Storage section≫ The storage unit 21 stores information about the size (total length L) of the vessel 1A, the destination (coordinates) of the vessel 1A, and the like.

[0019] ≪Own ship information acquisition department≫ The ship information acquisition unit 22 periodically acquires information (ship information) about the ship 1A and outputs the acquired ship information to the relative heading change speed calculation unit 24, the distance calculation unit 25, and the collision risk calculation unit 26. In this embodiment, the ship information acquisition unit 22 acquires the position information (latitude and longitude) of the ship 1A from the positioning device 13 as the ship information, and outputs the acquired position information to the relative orientation change speed calculation unit 24, the distance calculation unit 25, and the collision risk calculation unit 26. The vessel information acquisition unit 22 also acquires the vessel information of the vessel 1A from the vessel direction sensor 14 as the vessel information, and outputs the acquired vessel information to the relative vessel direction change speed calculation unit 24.

[0020] ≪Other ship information acquisition department≫ The other ship information acquisition unit 23 periodically acquires information (other ship information) about the other ship 1B and outputs the acquired other ship information to the relative heading change rate calculation unit 24, the distance calculation unit 25, and the collision risk calculation unit 26. In this embodiment, the other ship information acquisition unit 23 acquires position information (latitude and longitude) of the other ship 1B from the automatic identification system 11 as other ship information, and outputs the acquired position information to the relative heading change rate calculation unit 24, the distance calculation unit 25, and the collision risk calculation unit 26. In addition, the other ship information acquisition unit 23 acquires direction information of the other ship 1B from the automatic identification system 11 as other ship information, and outputs the acquired direction information to the relative heading change rate calculation unit 24.

[0021] <Relative heading change speed calculation section> The relative heading change speed calculation unit 24 acquires own ship information and other ship information, calculates the relative heading θ (see Figure 2) between the own ship 1A and the other ship 1B based on the acquired own ship information and other ship information, calculates the change speed of the relative heading θ (relative heading change speed) dθ / dt, and outputs the calculation result to the collision risk calculation unit 26. The relative heading θ is the heading of the other ship 1B relative to the own ship 1A. In a planar view, the relative heading θ is set to 0° ahead of the own ship 1A and to increase clockwise.

[0022] <Distance calculation section> The distance calculation unit 25 acquires the position information of the own ship 1A and the other ship 1B, calculates the distance D between the own ship 1A and the other ship 1B based on the acquired position information, and outputs the calculation result to the collision risk calculation unit 26.

[0023] <Collision Risk Calculation Unit> The collision risk calculation unit 26 calculates a collision risk R that indicates the risk of collision between the vessel 1A and the other vessel 1B, and outputs the calculation result to the notification device 31 and the route generation unit 27. The collision risk R is set to a larger value as the risk of collision between the vessel 1A and the other vessel 1B increases.

[0024] The collision risk calculation unit 26 acquires the relative heading change speed dθ / dt and calculates the collision risk R between the ship 1A and the other ship 1B based on the acquired relative heading change speed dθ / dt. In this embodiment, the collision risk calculation unit 26 calculates the collision risk R so that the smaller the absolute value of the relative heading change speed dθ / dt, the greater the collision risk R.

[0025] As shown in Figure 2, when the relative heading change rate dθ / dt is 0, that is, when the relative heading θ is constant and does not change, the ship 1A will collide with the other ship 1B. The collision risk calculation unit 26 can notify the crew of the ship 1A of the risk of collision with the other ship 1B by outputting the collision risk R that takes such an event into consideration to the notification device 31.

[0026] As shown in Fig. 1, the collision risk calculation unit 26 acquires the distance D and calculates the collision risk R between the ship 1A and the other ship 1B based on the acquired distance D and the overall length L of the ship 1A stored in the memory unit 21. In this embodiment, the collision risk calculation unit 26 calculates the collision risk R so that the collision risk R increases as the distance D decreases. In addition, the collision risk calculation unit 26 calculates the collision risk R so that the collision risk R increases as the overall length L increases.

[0027] 2, the smaller the distance D, the greater the risk of the vessel 1A colliding with the other vessel 1B. The collision risk calculation unit 26 can notify the crew of the vessel 1A of the risk of collision with the other vessel 1B by outputting the collision risk R that takes such events into consideration to the notification device 31.

[0028] 1, the collision risk calculation unit 26 acquires position information of the first ship 1A and the other ship 1B and heading information of the first ship 1A, calculates the relative heading θ based on the acquired position information and heading information, and calculates the collision risk R so that the collision risk R when the other ship 1B is located on the starboard side of the first ship 1A is greater than the collision risk R when the other ship 1B is located on the port side. Furthermore, the collision risk calculation unit 26 calculates the collision risk R so that the collision risk R when the other ship 1B is located on the starboard side and forward of the first ship 1A is greater than the collision risk R when the other ship 1B is located on the starboard side and astern. The collision risk calculation unit 26 may be configured to acquire the relative heading θ from the relative heading change speed calculation unit 24.

[0029] As shown in Figure 2, the ship 1A is required by law to navigate in a way that avoids the other ship 1B located on its starboard side (obligation to give way). The collision risk calculation unit 26 can notify the crew of the ship 1A of the need to navigate in a way that avoids a collision with the other ship 1B by outputting the collision risk R that takes such an event into consideration to the notification device 31.

[0030] As shown in FIG. 1, in this embodiment, the collision risk calculation unit 26 calculates the collision risk R based on the following formula.

[0031]

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[0032] Here, f(θ) is a function that takes a value greater than or equal to 0 and is larger when the other vessel 1B is located on the starboard side of the own vessel 1A than when it is located on the port side, and is expressed, for example, by the following equation. When 0°≦θ≦90°, f(θ)=1.0 When 90°<θ≦180°, f(θ)=0.5 When 180°<θ<360°, f(θ)=0.0

[0033] That is, f(θ) is set so that it is larger when the other ship 1B is located in range A1, A2 (see Figure 2) on the starboard side of the first ship 1A (0°≦θ≦180°) than when the other ship 1B is located in range A3 (see Figure 2) on the port side of the first ship 1A (180°<θ<360°). Furthermore, f(θ) is set so that it is larger when the other ship 1B is located in range A1 (0°≦θ≦90°) on the starboard side and forward of the first ship 1A than when the other ship 1B is located in range A2 (90°<θ≦180°) on the starboard side and rear of the first ship 1A.

[0034] Furthermore, w1, w2, and w3 are weighting coefficients for each term that take positive values, and are set so that the balance of each term is appropriate for the crew of the ship 1A, and the greater the risk of collision, the greater the collision risk R. For example, w1, w2, and w3 can be set to values ​​such that the collision risk R is 0 when there is almost no risk of collision between the ship 1A and the other ship 1B, and 100 when there is an extremely high risk of collision between the ship 1A and the other ship 1B.

[0035] ≪Route generation section≫ The route generation unit 27 acquires the collision risk R, generates a route for the ship based on the acquired collision risk R, and outputs the generated route to the steering unit 28. In detail, the route generation unit 27 acquires the detection results output from the automatic ship identification device 11, and generates a route based on the acquired detection results so as to avoid other ships 1B with a high collision risk R. The route generation unit 27 also acquires information output from the sea area information display device 12, and generates a route based on the acquired information so as to avoid running aground, etc.

[0036] <Navigation Department> The ship steering unit 28 acquires the route output from the route generation unit 27, and controls the power unit 32 and the steering unit 33 based on the acquired route so that the ship 1A navigates along the route.

[0037] The collision risk calculation device 20 according to the first embodiment of the present invention comprises a relative heading change rate calculation unit 24 that calculates the relative heading change rate, which is the rate of change of the relative heading of the other ship 1B relative to the own ship 1A, based on the heading of the own ship 1A and the heading of the other ship 1B, and a collision risk calculation unit 26 that calculates the collision risk R between the own ship 1A and the other ship 1B based on the calculated relative heading change rate, and the collision risk calculation unit 26 calculates the collision risk R so that the smaller the absolute value of the relative heading change rate, the greater the collision risk R. Therefore, the collision risk calculation device 20 can calculate the collision risk R using a simple method that does not use the speeds of the own ship 1A and the other ship 1B.

[0038] In the collision risk calculation device 20, the collision risk calculation unit 26 calculates the collision risk R so that the collision risk R increases as the distance D between the ship 1A and the other ship 1B decreases. Therefore, the collision risk calculation device 20 can calculate an appropriate collision risk R taking into consideration the distance D to the other vessel 1B.

[0039] In the collision risk calculation device 20, the collision risk calculation unit 26 calculates the collision risk R so that the collision risk R when the other vessel 1B is located on the starboard side of the first vessel 1A is greater than the collision risk R when the other vessel 1B is located on the port side of the first vessel 1A. Therefore, the collision risk calculation device 20 can calculate an appropriate collision risk R that takes into consideration the obligation to avoid collision based on the relative direction θ.

[0040] In the collision risk calculation device 20, when the relative direction is θ, the distance is D, the total length of the own ship 1A is L, f(θ) is a function that is larger when the other ship 1B is located on the starboard side of the own ship 1A than when it is located on the port side, the coefficients are w1, w2, w3, and the collision risk is R, the collision risk calculation unit 26 calculates the collision risk R using the following formula.

number

[0041] Second Embodiment Next, the second embodiment of the ship steering control system 2 of the present invention will be explained with reference to Figures 1 and 3, focusing on the differences from the first embodiment of the ship steering control system 2 (see Figure 2 for the overall length L of the ship itself and the distance D between the ship itself 1A and the other ship 1B).

[0042] In this embodiment, the own ship information acquisition unit 22 acquires the speed V of the own ship 1A as the own ship information, and outputs the acquired speed V to the collision risk calculation unit 26. In addition, the other ship information acquisition unit 23 acquires the speed V of the other ship 1B as the other ship information. r and obtain the velocity V r is output to the collision risk calculation unit 26. r may be detected by a speed sensor (speed sensor 15 in the case of the own ship 1A) provided on the ships 1A, 1B, or may be calculated based on time changes in the position information of the ships 1A, 1B. The own ship information acquisition unit 22 may calculate the speed V based on time changes in the position information of the own ship 1A, or calculate the speed V based on time changes in the position information of the other ship 1B. r The configuration may be such that the following is calculated.

[0043] The collision risk calculation unit 26 calculates the collision risk R by the following formula.

[0044]

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[0045] Here, w1, w2, w3, and w4 are weighting coefficients for each term that take positive values, and are set so that the balance of each term is appropriate for the crew of the ship 1A, and the greater the risk of collision, the greater the collision risk R. Also, w1 is the first term |dθ / dt| -1 is the weighting factor for F (V R / V). w1, w2, w3, and w4 can be set to values ​​such that the collision risk R is 0 when there is almost no risk of collision between the first ship 1A and the other ship 1B, and 100 when there is an extremely high risk of collision between the first ship 1A and the other ship 1B.

[0046] In this embodiment, the initial provisional values ​​of w1, w2, w3, and w4 are expressed by the following equations, for example. w1=0.6 w2=0.2 w3=0.2 w4=0.2 w1, w2, w3, and w4 can be appropriately set and changed based on the type of ship 1A and the sea area (congestion level, coastal topography, water depth, etc.).

[0047] Furthermore, F is a direction determination flag that indicates the result of determining whether the other ship 1B is in a direction that may result in a collision with the ship 1A. Based on the angles α, β, and θ (see Figure 3), the collision risk calculation unit 26 sets F = 1 when the other ship 1B is in a direction that may result in a collision with the ship 1A, and sets F = 0 when the other ship 1B is in a direction that does not result in a collision with the ship 1A. Here, angle α is the course relative to the ground of the ship 1A, and angle β is the course relative to the ground of the other ship 1B. Angles α and β are each the direction of travel of the ship relative to the Earth, and are values ​​where, for example, north is 0°. When 0°≦β-α≦180° and 0°≦θ≦180°, F=0 When 0°≦β-α≦180° and 180°<θ<360°, F=1 When 180°<β-α<360° and 0°≦θ≦180°, F=1 When 180°<β-α<360° and 180°<θ<360°, F=0

[0048] Furthermore, g(θ) is a function that is larger when the other vessel 1B is located on the starboard side of the vessel 1A than when the other vessel 1B is located on the port side. In this embodiment, g(θ) can be set in increments of 30°. The initial provisional value of g(θ) is expressed, for example, by the following formula. When 0°≦θ<30°, g(θ)=1.0 When 30°≦θ<60°, g(θ)=1.0 When 60°≦θ<90°, g(θ)=1.0 When 90°≦θ<120°, g(θ)=0.5 When 120°≦θ<150°, g(θ)=0.5 When 150°≦θ<180°, g(θ)=0.3 When 180°≦θ<210°, g(θ)=0.0 When 210°≦θ<240°, g(θ)=0.0 When 240°≦θ<270°, g(θ)=0.0 When 270°≦θ<300°, g(θ)=0.2 When 300°≦θ<330°, g(θ)=0.2 When 330°≦θ<360°, g(θ)=0.3 g(θ) can be appropriately set and changed based on the type of ship 1A and the sea area (congestion level, coastal topography, water depth, etc.) Note that g(θ) may be the same as the above-mentioned f(θ).

[0049] Also, V R (See FIG. 3) is the speed of the other vessel 1B relative to the vessel 1A, that is, the relative speed, and is expressed by the following formula:

[0050]

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[0051] Here, θ is the direction (relative direction) of the other ship 1B as seen from the ship 1A, and θ r(See Figure 3) is the direction (relative direction) of the ship 1A as seen from the other ship 1B.

[0052] In Figure 3, DCPA (Distance of Closest Point of Approach) is the distance (closest approach distance) to the point where the first ship 1A and the other ship 1B are closest to each other if they maintain their current course and speed. TCPA (Time of Closest Point of Approach) is the time until the point where the first ship 1A and the other ship 1B are closest to each other if they maintain their current course and speed.

[0053] Patent Document 1 describes a method for setting multiple risk assessment positions along the course of a ship and calculating a collision risk value for each of the multiple risk assessment positions. This method increases the amount of calculation required to calculate a collision risk value for each risk assessment position.

[0054] Furthermore, the technology described in Patent Document 1 describes a method for evaluating the risk of collision based on DCPA or TCPA, more specifically, a method for determining that there is a predetermined or higher risk of collision when DCPA is equal to or less than a predetermined value. With this method, the risk of collision is expressed as a binary choice, making it impossible to communicate the risk in detail to mariners.

[0055] In contrast, the collision risk calculation device 20 according to the second embodiment of the present invention has the object of calculating the risk of collision in detail while minimizing the amount of calculation, in addition to the above-mentioned object. That is, the collision risk calculation device 20 according to the second embodiment of the present invention calculates the risk of collision in detail by using θ as the relative direction, D as the distance, L as the overall length of the ship, g(θ) as a function that is larger when the other ship is located on the starboard side of the ship than when the other ship is located on the port side, F as a flag indicating whether the other ship is on a direction that will cause a collision with the ship, V as the speed of the ship, and V as the relative speed of the other ship as seen from the ship. R When the coefficients are w1, w2, w3, and w4, and the collision risk is R, the collision risk calculation unit 26 calculates the collision risk R by the following formula.

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[0056] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified as appropriate without departing from the gist of the present invention. For example, the ship maneuvering control system 2 may be configured to include a distance sensor that detects the distance D to another ship 1B around the ship 1A. In this case, the ship maneuvering control device 20 can omit the distance calculation unit 25.

[0057] 1A own ship 1B Other vessels 2. Ship steering control system 20 Ship steering control device (collision risk calculation device) 24 Relative heading change rate calculation section 26 Collision risk calculation unit

Claims

1. a relative heading change rate calculation unit that calculates a relative heading change rate, which is the rate of change of the relative heading of the other vessel with respect to the own vessel, based on the heading of the own vessel and the heading of the other vessel; a collision risk calculation unit that calculates a collision risk between the vessel and the other vessel based on the calculated relative heading change speed; Equipped with The collision risk calculation unit calculates the collision risk so that the collision risk increases as the absolute value of the relative heading change speed decreases. A collision risk calculation device characterized by:

2. The collision risk calculation unit calculates the collision risk so that the collision risk increases as the distance between the vessel and the other vessel decreases.

2. The collision risk calculation device according to claim 1.

3. The collision risk calculation unit calculates the collision risk so that the collision risk when the other vessel is located on the starboard side of the vessel is greater than the collision risk when the other vessel is located on the port side of the vessel.

3. The collision risk calculation device according to claim 2.

4. The relative direction is θ, the distance is D, the overall length of the own ship is L, the function f(θ) is larger when the other ship is located on the starboard side of the own ship than when it is located on the port side, and the coefficient is w 1 , w 2 , w 3 When the collision risk is R, the collision risk calculation unit calculates the collision risk by the following formula: [Equation 1] 4. The collision risk calculation device according to claim 3.

5. The relative direction is θ, the distance is D, the overall length of the own ship is L, a function g(θ) is larger when the other ship is located on the starboard side of the own ship than when it is located on the port side, a flag F indicating whether the other ship is in a direction that will cause a collision with the own ship, the speed of the own ship is V, and the relative speed of the other ship as seen from the own ship is V. R , coefficient w 1 , w 2 , w 3 , w 4 When the collision risk is R, the collision risk calculation unit calculates the collision risk by the following formula: [Equation 2] 4. The collision risk calculation device according to claim 3.

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