Variable speed avoiding system during navigation of ship channel
Technical Field
The invention relates to the field of ship navigation, in particular to a variable speed avoiding system during navigation of a ship channel.
Background
The shortest meeting Time (TCPA) and the shortest meeting Distance (DCPA) of two ships are two important factors for determining the collision risk of the ships, the DCPA reflects the collision risk degree between the two ships, and the TCPA reflects the urgent degree of the collision risk between the two ships. However, when ships travel along respective channels in the channels, DCPA is not an important reference factor for measuring the risk of collision of the ships. Before the ship passes through a navigation channel turning point, a driver needs to judge whether the ship meets a target ship at the turning point in advance and take measures of acceleration or deceleration to avoid the situation.
Technical personnel carry out a great deal of research work on the aspect of ship collision avoidance decision, such as the use of genetic algorithm in documents [1] and [2], the use of evolutionary algorithm in documents [3] and [4], and the use of heuristic algorithm in documents [5] and [6], and the research is suitable for the collision avoidance decision of ships in open water. In addition, some scholars have studied collision avoidance decisions of ships during navigation in the channel, and documents [7] and [8] utilize ant colony and bee colony algorithms to automatically generate a safe ship route, and the generated safe ship route is suitable for navigation in the channel under the conditions of speed change and direction keeping of the ship and speed and direction keeping of a target ship. The document [9] considers the influence of visibility limitation on ship collision avoidance tracks on the basis of an evolutionary algorithm. Document [10] uses time intervals to judge the DCPA value of the ship, and uses a linear expansion algorithm to approach the safe speed.
The basis for collision avoidance in these algorithms is to provide a safe enough encounter distance between the vessel and a stationary or static object, without consideration of the encounter location between the two vessels. In addition, the current marine radar has a function of trying to operate a ship, assuming that a target ship keeps a speed and a direction, the speed or the course of the ship is continuously changed, and the shortest meeting Time (TCPA) and the shortest meeting Distance (DCPA) of two ships are observed to judge the effectiveness of an avoidance measure. However, before pilot operation, parameters such as the speed and the course to be acquired, the display mode, the length of the vector line and the like need to be set by means of navigation experience, the operation is troublesome, the final avoidance effect is also uncertain greatly, the density of ships in a harbor is high, the practicability of variable-course water areas is poor, and the application effect is poor.
The traditional electronic chart or radar pilot ship is complex in function control, large in ship density in a port, poor in practicality in a water area with variable course and poor in application effect.
[1]Cheng X.and Liu Z.:Trajectory Optimization for Ship Navigation Safety Using Genetic Annealing Algorithm.Proceedings of ICNC 2007 Third International Conference on Natural Computation,4.,385–392,2007.
[2]MC Tsou,SL Kao,CM Su.Decision Support from Genetic Algorithms for Ship Collision Avoidance Route Planning and Alerts.Journal of Navigation,2010,63(1):167-182.
[3]Smierzchalski R.,Michalewicz Z.:Modelling of a Ship Trajectory in Collision Situations at Sea by Evolutionary Algorithm,IEEE Transactions on Evolutionary Computation.No.3Vol.4,227-241,2000.
[4]Zeng X.:Evolution of the Safe Path for Ship Navigation.Applied Artificial Intelligence.17.,87-104,2003.
[5]Xue Y.,Lee B.S.and Han D.:Automatic Collision Avoidance of Ships.Proceedings of the Institution of Mechanical Engineers,Part M:Journal of Engineering for the Maritime Environment,33-46,2009.
[6]Tsou M.C.and Hsueh C.K.:The Study of Ship Collision Avoidance Route Planning by Ant Colony Algorithm.Journal of Marine Science and Technology.18(5),746-756,2010a.
[7]A Lazarowska.Ship’s Trajectory Planning for Collision Avoidance at Sea Based on Ant Colony Optimisation.Journal of Navigation,2015,68(2):291-307.
[8]A Lazarowska.Swarm Intelligence Approach to Safe Ship Control.Polish Maritime Research,2015,22(4):34-40.
[9]R Szlapczynski.Evolutionary Planning of Safe Ship Tracks in Restricted Visibility.Journal of Navigation,2015,68(1):39-51.
[10]Jinfen Zhang,DiZhang,XinpingYan,SteinHaugen,C.GuedesSoares.A distributed anti-collision decision support formulation in multi-ship encounter situations under COLREGs.Ocean Engineering,2015,105:336-348.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a novel variable-speed avoidance module. If collision happens, the navigation speed of the ship is adjusted without changing the course, the collision avoidance can be realized, and the result can be displayed on the electronic chart in an image and digital mode.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a variable speed avoiding system for a ship during navigation on a channel is characterized by comprising an input module, a variable speed avoiding calculation module and an output module;
the input module collects navigation information of the ship and a target ship in real time, and the collection time is 0 time, and the initial longitude and latitude of the ship is
Speed of flight V
oCourse is C
oThe starting longitude and latitude of the target ship is
Course is C
TThe speed is V
TEstablishing a coordinate axis which takes the ship as a coordinate origin, takes the course as a y axis and takes the starboard direction as an x axis, wherein the relative azimuth angle of the two ships is TB; (ii) a
The variable speed avoidance calculation module comprises the following calculation steps:
step S01: calculating the sailing information of the ship and the target ship at t0Distance of time D0,
And will be a distance D0Decomposed into X-axis and y-axis, and the distance of X-axis is X ═ D0sinTB, Y-axis distance is Y ═ D0cosTB;
Step S02: calculating the position t of the ship and the target ship0Relative velocity V of timerThe calculation formula is
Wherein, VrxAnd VryAre each VrThe components in the x-axis and y-axis,
Vrx=VTx-VOsinCo
Vry=VTy-VOcosCo
wherein, VTxAnd VTyAre each VTThe components in the x-axis and y-axis,
if VrIf not, the process proceeds to step S03, otherwise, the process proceeds to step S04;
step S03: at this time VrWhen the ship is stationary relative to the target ship, the shortest meeting time TCPA and the shortest meeting distance DCPA of the two ships are respectively 0
TCPA=0,DCPA=Do
And proceeds to step S05;
step S04: at this time VrNot equal to 0, the shortest meeting time TCPA and the shortest meeting distance DCPA of the two ships are respectively
And proceeds to step S05;
step S05: judging whether avoidance is needed according to the shortest meeting time TCPA and the shortest meeting distance DCPA of the two ships calculated in the step S03 or the step S04, if the avoidance is not needed, returning to the step S01, and if the avoidance is needed, setting the meeting ship position of the ship as the meeting ship position
The distance from point O to point O' is
The speed of the ship needs to be adjusted to the following value
Wherein
a=D'o-X sin Co-Y cos Co
b=XVTx+YVTy-2D'oVTxsin Co-2D'oVTycos Co
VTx=VTsin CT
VTy=VTcos CT
Determining V 'according to the operation capacity of the ship'O1Or V'O2The new navigational speed of the ship;
the output module calculates the shortest meeting time TCPA, the shortest meeting distance DCPA and the new navigational speed V 'of the ship through the variable speed avoiding calculation module'O1Or V'O2And (6) outputting.
Further, the shortest meeting time TCPA, the shortest meeting distance DCPA and the new speed V 'of the ship output by the output module'O1Or V'O2And outputting the images and/or the numbers to the electronic chart.
According to the technical scheme, the variable-speed avoidance of the target ship can be completed only by adjusting the navigation speed of the ship without adjusting the course of the ship, two schemes of acceleration or deceleration are provided, an operator can select one scheme according to the actual performance of the ship and other factors, and image display can be realized on the electronic chart. Therefore, the invention has the obvious characteristics of simplicity, easy implementation, obvious effect and visual display.
Drawings
FIG. 1 is a schematic illustration of a encounter in accordance with an embodiment of the present invention;
FIG. 2 is a schematic diagram illustrating a deceleration avoidance effect according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an accelerated avoidance effect according to an embodiment of the present invention.
Detailed Description
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
In the following detailed description of the embodiments of the present invention, in order to clearly illustrate the structure of the present invention and to facilitate explanation, the structure shown in the drawings is not drawn to a general scale and is partially enlarged, deformed and simplified, so that the present invention should not be construed as limited thereto.
In the following embodiments of the present invention, the present invention comprises an input module, a shift avoidance calculation module and an output module;
the input module collects navigation information of the ship and a target ship in real time, and the collection time is 0 time, and the initial longitude and latitude of the ship is
Speed of flight V
oCourse is C
oThe starting longitude and latitude of the target ship is
Course is C
TThe speed is V
TEstablishing a coordinate axis which takes the ship as a coordinate origin, takes the course as a y axis and takes the starboard direction as an x axis, wherein the relative azimuth angle of the two ships is TB;
the variable speed avoidance calculation module comprises the following calculation steps:
step S01: calculating the position t of the ship and the target ship0Distance of time D0,
And will be a distance D0Decomposed into X-axis and y-axis, and the distance of X-axis is X ═ D0sinTB, Y-axis distance is Y ═ D0cosTB
Step S02: calculating the position t of the ship and the target ship0Relative velocity V of timerThe calculation formula is
Wherein
Vrx=VTx-VOsin Co
Vry=VTy-VOcos Co
If VrIf not, the process proceeds to step S04, otherwise, the process proceeds to step S05;
step S03: at this time VrWhen the ship is stationary relative to the target ship, the shortest meeting time TCPA and the shortest meeting distance DCPA of the two ships are respectively 0
TCPA=0,DCPA=Do
And proceeds to step S05;
step S04: at this time VrNot equal to 0, the shortest meeting time TCPA and the shortest meeting distance DCPA of the two ships are respectively
And proceeds to step S05;
step S05: judging whether avoidance is needed according to the shortest meeting time TCPA and the shortest meeting distance DCPA of the two ships calculated in the step S03 or the step S04, if the avoidance is not needed, returning to the step S01, if the avoidance is neededThe meeting ship site of the ship is set as
Distance from point O to point O ″
The ship needs to adjust the navigational speed to a lower value
Wherein
a=D'o-X sin Co-Y cos Co
b=XVTx+YVTy-2D'oVTxsin Co-2D'oVTycos Co
VTx=VTsin CT
VTy=VTcos CT
Determining V 'according to the operation capacity of the ship'O1Or V'O2Is the new speed of the ship, if adjusted to V'O1Is accelerated avoidance, e.g. adjusted to V'O2The deceleration avoidance is performed. At the same time, the ship course CoRemain unchanged.
The output module calculates the shortest meeting time TCPA, the shortest meeting distance DCPA and the new navigational speed V 'of the ship through the variable speed avoiding calculation module'O1Or V'O2And (6) outputting.
The shortest meeting time TCPA, the shortest meeting distance DCPA and the new navigational speed V 'of the ship output by the output module'O1Or V'O2Output to in an image and/or digital mannerOn the electronic chart.
In order to verify the effectiveness of the algorithm, in this embodiment, the computing software is written in C + + language, a typical channel is selected for verification, and the result is displayed on the electronic chart. In the experiment, the direction and the speed of the target ship are kept, and the ship dodges the target ship by increasing or reducing the speed.
FIG. 3 shows a routing intersection in the area B of the Yangtze river, and many ships are sailed in the east-west direction and the south-north direction. The ship sails from east to west into a south channel, the heading is 283 degrees, the speed is 10kn, the starboard direction is 312.9 degrees, a target ship sails from north to south at a distance of 8n mile, the shortest meeting distance between the ship and other ships is 0.493n mile, and the meeting position is located at a channel intersection. In order to avoid meeting with the target ship at the intersection of the navigation channel, the ship needs to adopt a variable speed avoidance measure and keep the shortest meeting distance of 1.0n mile with other ships. The ship moves backwards along the course of the ship and meets the ship position, which means that the ship takes a deceleration measure to avoid the ship, and moves forwards and meets the ship position, which means that the ship takes an acceleration measure to avoid the ship. The results of the experiment are shown in Table 1, when the ship decelerates to 8.5kn (FIG. 2) or accelerates to 16.9kn (FIG. 3), the two ships do not meet at the intersection, and DCPA equals 1 mil.
Table 1: calculation of the results of the experiment
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.