JPS61204518A - Obstacle avoiding sailing method for ship - Google Patents

Abstract

PURPOSE:To facilitate the setting of a course and to sail a ship by the shortest distance by substituting the spread of an obstacle in a sea area with a set section of grating-shaped measures and selecting a shorter course between courses which are circumscribed and has the smallest number of inflections. CONSTITUTION:The sea area from a present position P0 to a target position P1 is sectioned in a grating shape of measures which have one division of a minimum turn radius corresponding to a specific sailing speed. The spread of the obstacle 1 is substituted with a set of sections 5. Then, two courses which extend from the current position P0 to the target position P1 while circumscribed with the set of sections 5 and have the smallest number of inflections, i.e. P0-P6-P7-P1 and P0-P10-P11-P13-P1 are set and the right-side shorter route is selected. Consequently, the setting of the course is facilitated and the ship is sailed by the shortest distance while avoiding the obstacle.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a system for avoiding dangerous obstacles such as islands, floating objects, ships, etc. in the scheduled navigation area in front of the own ship through the shortest avoidance route. This relates to methods of giving way for ships.

[Prior art] Conventionally, when a ship discovers an obstacle within the area it is scheduled to navigate, in addition to following the provisions of the Maritime Collision Prevention Act, it reduces the ship's speed as necessary and takes sufficient measures to avoid the obstruction. They kept their distance and took detours, and operated the ship with safety first.

[Problem to be solved by the invention] However, as ships are becoming larger and faster, reducing the ship's speed and making large detours is disadvantageous in terms of ship handling technology and operational economics, and there is no rational way to give way. Various studies have been conducted.

[Means for solving the problems] The present invention has been made to solve the above-mentioned problems.
A method of giving way for a ship to avoid dangerous navigational obstacles existing in the scheduled navigation area and reach a target position from the current position, the patent item is characterized by a minimum turning radius corresponding to a predetermined ship speed. The area is divided into a grid pattern, and the planar spread of obstacles is replaced by a collection of squares that include the obstacles. A route that circumscribes the gathering area through the target position and the number of course changes is determined, and the sailing route is compared with the knownness of the route and the route is navigated on a shorter route of h. Something like that T: Yes.

[Function] The position of obstacles and ships in JrC areas and sea areas, and the route are replaced with grid grids to determine the relative positions of ships and obstacles, making it easier to set routes and avoid obstacles. By setting the route with the minimum number of refractions circumscribing the represented gathering area as the avoidance route, it is possible to avoid by the shortest distance without reducing the C1 ship speed. Therefore, it is possible to shorten navigation time and save fuel, and it is possible to rationalize avoidance methods.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the first example in which the method of the present invention is applied to a fixed obstacle.
In the figure, PO is the current position of own ship,
P+ is the target position to be reached, 1 is P. This is a fixed obstacle (such as an island) that crosses the straight line 2 connecting P1 and P1 and is detected using a detector such as a radar.

In the present invention, the current position P. The sea area with the required width D (for example, ship speed x 3 hours distance on both sides with straight line 2 as the center) to reach the target device P1 is divided into a grid pattern using squares 3, which will be described later. Displays the planar extent of the object 1, the position of the ship, the route, etc. In other words, the spread of the obstacle 1 is represented by a gathering section 5 whose periphery is the square cut off by the obstacle contour 4, and the position of the ship, such as the current position Po and the target position P1, is represented by one square. , the route is roughly represented by a row of squares.

The significance of using grids is that, for example, by replacing the state where two objects or a line and an object are closest to the state where the grid is adjacent to phase U, it is possible to easily and clearly handle the positional relationship between objects. That's the point. The size d of the grid 3 is preferably set to the minimum turning radius of the ship from the viewpoint of the purpose of the present invention, that is, to allow the ship to approach obstacles as much as possible and avoid collisions.

The minimum turning radius depends on the ship's speed, so when navigating in narrow waterways or in ports, reduce the ship's speed and set smaller squares, and when navigating across wide waterways, increase the ship's speed and set smaller squares. Set to a large value.

Below, the procedure for setting an avoidance route will be explained step by step. First, a straight route 2a (a row of squares) connecting the current position Po and the target position P1 is imagined, and the position of a square where this straight route 2a intersects with the periphery of the gathering section 5 and is adjacent to this periphery is designated as P2. , P3 (where P2 and P3 are squares closer to the current position Po and target position P1, respectively) (Step 1).

Next, two routes P2-P, +-Ps -P--P7-P, a counterclockwise direction and a clockwise direction, lead from the position P2 to the position P3 through the squares adjacently surrounding the outside of the gathering section 5.
, -P, -P3, P2- Pl--Pl, -P12-
Draw P,, -P3 (indicated by a dashed line) (Step 2)
.

Then, the route from the position Po through all or part of the refraction points on the two routes to the target position P1 with the minimum number of refractions, that is, the route circumscribing the gathering area 5 Po-ρ=
Draw P, P+, Pa-Pl・-PII-Pl--P+ (Step 3).

In the above, all or part of the refraction point refers to, for example, in the case of a shape in which the refraction point is located near P2 and P3 as shown in FIG. 1, these points Pa.

This means that Ps, P=, P=, P,, Pl- are excluded from the route to be sought, and the route to be sought is as if the ring of rubber string is connected to the gathering area 5 and the current position]
] o and the shape of the rubber string when it is fitted outside the target position P1 will be easier to understand.

Now, returning to the main application, after R there are two routes Po P@
P7P+, and P. -p to p,.

-P2. - Compare the route lengths of P+ and choose the shorter route Po.
P. -P,, -P,,'' -P+ is set as an avoidance route (Step 4).

A second embodiment of the invention is shown in FIG. This example
The method of the present invention is applied to the obstacles that are detected, and the detected obstacles are represented as a gathering section 5a (shown surrounded by a thin solid line and hatched) at the position shown in the figure, and this gathering section 5a is Assume that the vehicle is moving diagonally across the straight route 2a at a speed of V1.

The procedure for setting the avoidance route is the same as [Procedure 1] in the first embodiment.
, and according to step 2, draw a counterclockwise route p, bp, , -pI7p, surrounding the outside of the gathering area 5a, and a clockwise route P1--P1. The turning point of the clockwise route that passes just in front of.

P. , P, 1 is calculated using equations (1) and (9), and the refraction point P221p!+ of the counterclockwise route passing immediately after the obstacle is calculated using equations (3) and (4). Find the route PQ P,, P□-P that circumscribes the gathering area.
l and Po P22- P2. -P+ (step 3), compare the distances of the two circumscribed routes, and select the shorter one as the avoidance route (step 4).

V2 COS θ+ ・tl +f=V+
N-)V+ cos Ot (tl +1/V
) > (1) Formula y2 sinθ+ φj
+ =h4-V+ 5in(1'・tl +V1 si
nα-7, /V2 (2) Formula V2CO3θ2 ・j2=
V+V+ CO3(X ・[y
(3) Formula, sinθ2・tl = ! -V+
Sin (X-tz
(4) where, vl: Obstacle moving speed V2: Vessel speed θ1. θ2: Angle between the straight route and the circumscribed route α: Angle between the straight route and the direction of obstacle movement tl, t2: When the ship p2. , p2. Time to reach 1: P, , Distance between P: h: pl~, Distance between PIe +: P +1. P3. Distance between v: P l) l P l, is the distance between.

Equations (1) and (2) indicate that the ship passes P2- and P
, when reaching I, it matches Pl after the movement,
That is, it means that the ship passes by dodging the upper right corner of the obstacle, and equations (3) and (4) indicate that the ship passes the obstacle at P2.
When reaching , it matches Rs after movement, which means that the vessel passes by dodging the lower left corner of the obstacle.

In the second embodiment, the bending point (P in Fig. 2) where the ship barely passes in front of or behind the obstacle is
P3. ) (hereinafter referred to as a proximate refraction point), but if it is difficult to distinguish due to the shape of the gathering section, use the formula (1) or ) is used to find the closest refraction point that causes the most problem, and the shortest of the clockwise and counterclockwise circumscribed routes that pass through the closest refraction point is set as the avoidance route.

E Effects of the Invention] As described above, the present invention exhibits the following excellent effects.

(i) Obstacles in the sea area and within the area, the positions of ships, and routes are replaced with grid grids to understand the relative positions of ships and obstacles, making it easier to set ship routes and to represent obstacles. Since a route with the minimum number of refractions is set that circumscribes the gathering area, it is possible to give way at the shortest distance without reducing ship speed.

(ii) As a result of item (+), the distance between navigation sections can be shortened and fuel can be saved.

@ The size of square [1] that divides the ocean area is set as the minimum turning radius that depends on the ship speed, so by increasing or decreasing the ship speed and setting the square larger or smaller, wide area navigation and narrow area navigation can be achieved. It can be applied to any navigation.

(F) Since the size of the grid can be set appropriately according to turning performance, excellent maneuverability can be used to improve the accuracy of route setting.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing how to set avoidance routes according to first and second embodiments of the present invention, respectively. In the diagram, 1 is a fixed obstacle, 2a is a straight route, 3 is a square,
5 and 5a are gathering sections, Po is the current position, and Pl is the target position. Patent application: Wooden Ship Research Association Patent application: Hitoshi Kawasaki Heavy Industries, Ltd. Patent application: Hitachi Kawasaki Heavy Industries, Ltd. Patent application: Hitachi Zosen Corporation Patent application: Hitachi Sumitomo Heavy Industries, Ltd. Co., Ltd.

Claims (1)

[Claims] 1) In the avoidance method for a ship to avoid dangerous navigational obstacles that exist in the planned navigation area and reach the target position from the current position, a square with one scale as the minimum turning radius corresponding to a predetermined ship speed Divide the sea area into a grid pattern, replace the planar spread of obstacles with clusters of squares that include the obstacles, and divide each sea area into two by a straight route connecting the current position and the target position. A ship characterized in that a route circumscribing the gathering area through the current position and a target position and minimizing the number of course changes is determined, and the length of the route is compared to navigate the shorter route. Avoidance method.