Direct navigation ship collision avoidance decision-making method and system

Abstract

The invention provides a direct navigation ship collision avoidance decision-making method and system, and the method comprises the steps: determining an encounter situation between ships based on ship information, collision avoidance rules and navigation environment information, constructing a ship domain model of the ships, and determining a minimum safe encounter distance and a ship safe passing distance; determining a collision risk degree based on the minimum safety encounter distance, the ship safety passing distance and the ship information; determining a ship meeting stage based on the collision risk degree and a four-stage theoretical model, and determining collision avoidance responsibility between the ships based on the ship meeting stage and the meeting situation between the ships; based on the meeting situation between the ships, the collision risk degree, the collision avoidance responsibility between the ships and the ship meeting stage, the straight ship avoiding opportunity is determined; constructing a speed obstacle set based on the ship maneuverability coefficient and the trajectory information of the direct navigation ship and the way-giving ship; and determining a collision avoidance decision scheme of the direct navigation ship based on the navigation environment information, the speed obstacle set and the ship control motion model. And theoretical guidance is provided for the marine collision avoidance action of the direct navigation ship.

Description

Technical Field

[0001] The present invention relates to the technical field of ship collision avoidance, and in particular to a collision avoidance decision-making method and system for a direct-navigation ship. Background Art

[0002] Ship accidents have profound impacts on human life, the environment, and property. Numerous accident investigations have shown that human error, including operational errors and poor decision-making, is the primary contributing factor. The European Maritime Safety Agency (EMSA)'s 2023 Annual Report on Maritime Accidents shows that 59.1% of ship accidents between 2014 and 2022 were caused by human error. The development of intelligent ships has significantly reduced human risk, leading to a gradual decrease in the frequency of accidents. Breakthroughs in artificial intelligence, communications, and information systems have driven the rapid advancement of intelligent ship technology, prompting more scholars and institutions to focus on research on autonomous navigation decision-making.

[0003] Existing research on autonomous navigation decision-making systems and collision avoidance solutions has largely focused on yielding vessels, while lacking in-depth research on the avoidance timing of direct-travel vessels and their collision avoidance behavior in critical situations. Currently, direct-travel vessel collision avoidance decisions rely primarily on the crew's subjective judgment of other vessels' actions, which can easily increase the risk of collision due to misjudgment.

[0004] Therefore, it is urgent to provide a collision avoidance decision-making method and system for direct-navigation ships. Taking direct-navigation ships as the research object, determining the appropriate time for direct-navigation ships to initiate collision avoidance actions and the collision avoidance decision-making plan for direct-navigation ships is of great significance to ensuring the safety of ship navigation and promoting intelligent ship navigation. Summary of the Invention

[0005] In view of this, it is necessary to provide a collision avoidance decision-making method and system for direct-navigation ships to solve the technical problem in the existing technology that the collision avoidance decision-making of direct-navigation ships mainly relies on the subjective judgment of the crew, resulting in low accuracy and rationality of the ship's collision avoidance decision-making plan.

[0006] In a first aspect, in order to solve the above technical problems, the present invention provides a collision avoidance decision-making method for a straight-line ship, comprising: Obtain information on ships and navigation environment in the research waters; Determine the encounter situation between the ships based on the ship information and collision avoidance rules; Building a ship domain model of the ship based on the ship information and the navigation environment information, and determining a minimum safe encounter distance and a safe passing distance of the ship based on the ship information; determining a multi-factor risk membership based on the minimum safe encounter distance, the safe ship passing distance, and the ship information, and determining a collision risk of the ship based on the multi-factor risk membership; Determining the ship encounter phases based on the collision risk and the four-phase theoretical model, wherein the ship encounter phases include a free action phase, a give-way ship action phase, a direct-flowing ship action phase, and a phase where both ships take action; Determine the responsibility for avoiding collision between ships based on the stage of encounter and the situation of encounter between ships; determining a timing for the direct-line vessel to give way based on the encounter situation between the vessels, the collision risk, the collision avoidance responsibilities between the vessels, and the encounter stage; Obtaining a ship maneuverability coefficient of the straight-navigation ship, and constructing a speed barrier set based on the ship maneuverability coefficient and trajectory information of the straight-navigation ship and the give-way ship; A collision avoidance decision plan of the straight-navigation ship is determined based on the navigation environment information, the speed obstacle set and the ship maneuvering motion model of the straight-navigation ship, and the straight-navigation ship is controlled to navigate according to the collision avoidance decision plan.

[0007] In a possible implementation, the ship domain model is:

[0008]

[0009]

[0010]

[0011]

[0012]

[0013] Where, is the radius length of the ship area in the positive direction of the X-axis of the ship coordinate system; is the radius length of the ship area in the negative direction of the X-axis of the ship coordinate system; is the radius length of the ship area in the positive direction of the Y axis of the ship coordinate system; is the radius length of the ship area in the negative direction of the Y axis of the ship coordinate system; is the coefficient of gyration diameter; is the ship's advance coefficient; is the captain of a ship; is the ship speed; the ship coordinate system is a coordinate system with the center of gravity of the ship as the origin, the direction pointing to the bow as the positive direction of the X axis, and the direction pointing to the starboard side of the ship as the positive direction of the Y axis.

[0014] In a possible implementation, the minimum safe encounter distance is:

[0015] The safe passage distance for ships is:

[0016] Where, The minimum safe encounter distance; Provide safe passage distance for ships; is the azimuth of the ship.

[0017] In a possible implementation, the multi-factor risk membership includes closest approach distance membership, closest approach time membership, distance membership, speed ratio membership, relative bearing membership, and ship maneuverability membership; The closest encounter distance membership for:

[0018] The nearest encounter time membership for:

[0019] The distance membership for:

[0020] The speed ratio membership for:

[0021] The relative orientation membership for:

[0022] The ship maneuverability membership for:

[0023] Where, DCPA is the distance of closest encounter of ships; TCPA is the time of closest encounter of ships; is the absolute value symbol; is the time of ship collision; Note time for ships; D is the distance between the two ships; k is the speed ratio between the two ships; C To touch the corner; Q is the relative bearing of the two ships; is the ship field coefficient; K is the ship maneuverability coefficient.

[0024] In a possible implementation, the collision risk is:

[0025]

[0026] Where, is the weight of the closest encounter distance membership; is the weight of the membership of the most recent encounter time; is the weight of distance membership; is the weight of the speed ratio membership; is the weight of relative orientation membership; is the weight of the ship's maneuverability membership.

[0027] In a possible implementation, the speed barrier set is:

[0028] Where, is the speed obstacle set at the current moment; For the current moment; and are the trajectories of the two ships at time t; is the radius of the ship's field area; are the positions of the two ships at time t; is the Minkowski operator symbol.

[0029] In a possible implementation, determining the ship encounter stage based on the collision risk and the four-stage theoretical model includes: determining a first risk threshold for the free action phase, a second risk threshold for the give-way vessel action phase, a third risk threshold for the direct-passage vessel action phase, and a fourth risk threshold for the phase in which both vessels take action in the four-phase theoretical model; the first risk threshold being less than the second risk threshold, the second risk threshold being less than the third risk threshold, and the third risk threshold being less than the fourth risk threshold; When the collision risk is less than or equal to the first risk threshold, the ship encounter phase is determined to be a free action phase; when the collision risk is greater than the first risk threshold and less than or equal to the second risk threshold, the ship encounter phase is determined to be a give-way ship action phase; when the collision risk is greater than the second risk threshold and less than or equal to the third risk threshold, the ship encounter phase is determined to be a straight-through ship action phase; when the collision risk is greater than the third risk threshold and less than or equal to the fourth risk threshold, the ship encounter phase is determined to be a phase in which both ships take action.

[0030] In one possible implementation, the responsibility for avoiding collision between ships is determined based on the ship encounter phase and the encounter situation between the ships, including: determining whether the ship encounter phase is a give-way ship action phase, a keep-straight ship action phase, and a both ships action phase; If yes, when the ship encounter situation is an overtaking situation, the overtaking ship is the give-way ship and the overtaken ship is the keep-straight ship; when the ship encounter situation is a crossing situation, the ship seeing the other ship on the left is the give-way ship and the ship seeing the other ship on the right is the keep-straight ship.

[0031] In a possible implementation, the ship maneuvering motion model is:

[0032] wherein, T 1、 T 2、 T 3 is a time constant related to the ship type; K is a ship maneuverability coefficient; is a rudder angle; is a rate of change of the rudder angle; r is a yaw rate; is an acceleration of the yaw rate; is a rate of change of the acceleration of the yaw rate.

[0033] In a second aspect, the present application further provides a keep-straight ship collision avoidance decision system, comprising: a basic information acquisition unit configured to acquire ship information and navigation environment information in a research water area; an encounter situation determination unit configured to determine a ship encounter situation based on the ship information and a collision avoidance rule; a ship field model construction unit configured to construct a ship field model of the ship based on the ship information, and determine a minimum safe encounter distance and a ship safe passing distance of the ship based on the ship information; a collision risk determination unit configured to determine a multi-factor risk membership degree based on the minimum safe encounter distance, the ship safe passing distance, and the ship information, and determine a collision risk of the ship based on the multi-factor risk membership degree; a ship encounter phase determination unit configured to determine a ship encounter phase based on the collision risk and a four-phase theory model, the ship encounter phase being a free action phase, a give-way ship action phase, a keep-straight ship action phase, and a both ships action phase; a collision avoidance responsibility determination unit configured to determine a collision avoidance responsibility between ships based on the ship encounter phase and the ship encounter situation; a keep-straight ship avoidance opportunity judgment unit configured to determine a keep-straight ship avoidance opportunity based on the ship encounter situation, the collision risk, the collision avoidance responsibility between ships, and the ship encounter phase. a speed barrier set constructing unit, configured to obtain a ship maneuverability coefficient of the straight-routing ship, and construct a speed barrier set based on the ship maneuverability coefficient and the trajectory information of the straight-routing ship and the give-way ship; A collision avoidance decision unit is used to determine a collision avoidance decision plan for the straight-navigation ship based on the navigation environment information, the speed obstacle set and the ship maneuvering motion model of the straight-navigation ship, and control the straight-navigation ship to navigate according to the collision avoidance decision plan.

[0034] The beneficial effects of the present invention are as follows: the direct-navigation ship collision avoidance decision-making method provided by the present invention considers multi-factor risk membership when determining the collision risk. Compared with the collision risk determined by a single-factor risk membership, the collision risk determined by the multi-factor risk membership is more accurate, providing a more accurate reference factor for direct-navigation ship collision avoidance decisions. At the same time, the parameters of four dimensions—the four-stage theoretical model, the encounter situation between ships, the collision risk, and the collision avoidance responsibility between ships—are taken into account in the process of determining the direct-navigation ship's collision avoidance timing. This also takes into account factors such as different encounter scenarios and encounter stages, further improving the accuracy of determining the direct-navigation ship's collision avoidance timing. Furthermore, when constructing the speed barrier set, the direct-navigation ship's ship maneuverability coefficient is taken into account, that is, the ship's maneuverability is taken into account when constructing the speed barrier set, further improving the reliability of the constructed speed barrier set. In summary, the direct-navigation ship collision avoidance decision-making method provided by the present invention can provide direct-navigation ships with accurate and reliable ship collision avoidance strategies, improving the decision-making ability and navigation safety of autonomous navigation systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 A schematic flow chart of an embodiment of the direct-navigation ship collision avoidance decision-making method provided by the present invention; Figure 2 A schematic diagram of an embodiment of the present invention showing how the speed barrier set changes with time steps; Figure 3 A schematic diagram of an embodiment of simulating the maneuvering trajectories of different types of ships based on the ship maneuvering motion model provided by the present invention; Figure 4 This is a schematic structural diagram of an embodiment of the direct-navigation ship collision avoidance decision-making system provided by the present invention. DETAILED DESCRIPTION

[0037] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0038] It should be understood that the schematic drawings are not drawn to scale. The flowcharts used in the present invention illustrate operations implemented according to some embodiments of the present invention. It should be understood that the operations of the flowcharts can be implemented out of sequence, and steps that have no logical contextual relationship can be reversed in order or implemented simultaneously. In addition, those skilled in the art, guided by the content of the present invention, can add one or more other operations to the flowcharts or remove one or more operations from the flowcharts. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different networks and / or processor systems and / or microcontroller systems.

[0039] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0040] The present invention provides a collision avoidance decision-making method and system for a straight-line ship, which are described below respectively.

[0041] Figure 1 A flow chart of an embodiment of the direct-travel ship collision avoidance decision-making method provided by the present invention is shown as follows: Figure 1 As shown in Figure 2, the collision avoidance decision-making method for straight-line ships includes: S101. Obtain vessel information and navigation environment information within the research waters.

[0042] The ship information includes the length, width, position, speed and heading of the ship, etc. The navigation environment information includes the position and boundaries of dynamic and static obstacles in the navigation waters, etc.

[0043] Specifically, ship information and navigation environment information can be obtained based on important ship equipment such as radar, video equipment, GPS and AIS.

[0044] S102. Determine the encounter situation between ships based on ship information and collision avoidance rules.

[0045] S103: Constructing a ship domain model of the ship based on the ship information and the navigation environment information, and determining a minimum safe encounter distance and a safe passing distance of the ship based on the ship information; S104. Determine a multi-factor risk membership based on the minimum safe encounter distance, the safe ship passing distance, and the ship information, and determine a collision risk of the ship based on the multi-factor risk membership; S105. Determine the ship encounter phases based on the collision risk and the four-phase theoretical model. The ship encounter phases are the free action phase, the give-way vessel action phase, the direct-route vessel action phase, and the phase where both ships take action.

[0046] Specifically, the free action phase is the initial stage, during which all vessels have unrestricted freedom of movement. During this phase, which occurs over considerable distances, each vessel can take any necessary action. However, compliance with collision avoidance regulations and safe speed regulations remains mandatory. Neither give-way vessels nor direct-course vessels are required to take any special action at this time.

[0047] The give-way vessel action phase is the early stage of a potential conflict, requiring the give-way vessel to take swift evasive action to prevent a collision. Vessel pilots should use all available measures, while maintaining the vessel's speed and course, and continuously assess the effectiveness of the give-way vessel's collision avoidance decisions. This phase is often referred to as the "golden period" for the give-way vessel to initiate evasive maneuvers. The rationale behind this approach is twofold: first, early action complies with the principles of the collision regulations and provides more time for effective situation management; second, it allows those on board to observe and verify the existence of a conflict after the collision avoidance maneuvers, thereby improving safety. While determining the exact timing of the second phase is crucial, the collision regulations do not provide detailed guidance. Some studies use the navigation light ranges specified in the collision regulations to define the second phase, while vessel pilots assess the encounter phase based on the orientation of the navigation lights and other nighttime indicators. The navigation light ranges specified in the collision regulations establish the reasonable range within which the second phase should occur and are consistent with maritime practice.

[0048] The directing vessel action phase is when the risk of collision between the two vessels increases dramatically, especially if the giving way vessel does not take appropriate action in a timely manner to comply with the collision avoidance regulations. During this phase, the directing vessel is allowed to continue its navigation, but the giving way vessel is still required to take action.

[0049] The riskiest phase of an encounter is when both vessels take action. As the conflict escalates, the avoidance action of the give-way vessel is insufficient to prevent a collision. If neither vessel takes prompt action to prevent a collision, a collision will occur quickly.

[0050] S106. Determine the collision avoidance responsibility between the ships based on the ship encounter stage and the encounter situation between the ships.

[0051] Since collision avoidance liability refers to the liability of the ship when there is a collision risk, step S106 is specifically as follows: First, determine whether the encounter phase between ships is the give-way ship action phase, the direct-course ship action phase, or the phase where both ships take action; when the encounter phase between ships is the give-way ship action phase, the direct-course ship action phase, or the phase where both ships take action, then determine the collision avoidance responsibility between the ships based on the encounter situation between the ships.

[0052] Among them, the specific responsibility for avoiding collision between ships is determined by the encounter situation between ships: When the encounter between two ships is an overtaking situation, the overtaking ship is the give-way ship and the overtaken ship is the direct-travel ship; When the encounter between ships is a head-on encounter, both ships are give-way ships; When the encounter situation between ships is a crossing encounter, the ship that sees the other ship on the port side is the give-way ship, and the ship that sees the other ship on the starboard side is the straight-line ship.

[0053] In addition to the above-mentioned situations, in actual maritime navigation, there are also sailboats, ships with limited control, and ships out of control. The specific division of responsibilities for these ships is as follows: When the vessels are sailing: If the wind is not on the same side, the vessel on the port side is the give-way vessel. The vessel on the starboard side is the straight-track vessel. If the wind is on the same side, the vessel upwind is the give-way vessel, and the vessel downwind is the straight-track vessel.

[0054] Vessels with limited maneuverability and out-of-control vessels are not responsible for giving way, and direct-traveling vessels should avoid such vessels as much as possible.

[0055] S107. Determine the time for the direct-travel vessel to give way based on the encounter situation between the vessels, the collision risk, the collision avoidance responsibilities between the vessels, and the stage of the encounter.

[0056] Among them, the avoidance timing of the direct-navigation ship refers to the moment when the direct-navigation ship makes a collision avoidance decision. Accurate determination of the avoidance timing of the direct-navigation ship can improve the navigation safety of the direct-navigation ship.

[0057] S108, obtaining the ship maneuverability coefficient of the straight-line ship, and constructing a speed obstacle set based on the ship maneuverability coefficient and the trajectory information of the straight-line ship and the give-way ship; S109: determining a collision avoidance plan for the straight-navigation ship based on the navigation environment information, the speed obstacle set, and the ship maneuvering motion model of the straight-navigation ship, and controlling the straight-navigation ship to navigate according to the collision avoidance plan.

[0058] It should be understood that the direct-navigation ship collision avoidance decision-making method in the embodiments of the present invention can be implemented in any device based on the direct-navigation ship collision avoidance decision-making method, such as a ship's control device. Specifically, the direct-navigation ship collision avoidance decision-making method is stored in the aforementioned device as a pre-programmed program. When the device is activated, the program is invoked and the direct-navigation ship collision avoidance decision-making method is implemented.

[0059] Compared to existing technologies, the collision avoidance decision-making method for direct-navigation ships provided in embodiments of the present invention considers multi-factor risk membership when determining collision risk. This makes the collision risk determined by multi-factor risk membership more accurate than that determined by a single-factor risk membership, providing a more accurate reference factor for direct-navigation ship collision avoidance decisions. Furthermore, the method incorporates parameters from four dimensions—the four-stage theoretical model, the encounter situation between ships, the collision risk, and the collision avoidance responsibility between ships—in the process of determining the collision avoidance timing for direct-navigation ships. This consideration takes into account factors such as different encounter scenarios and encounter stages, further improving the accuracy of determining the collision avoidance timing for direct-navigation ships. Furthermore, the maneuverability coefficient of the direct-navigation ship is taken into account when constructing the speed barrier set. This further improves the reliability of the constructed speed barrier set. In summary, the collision avoidance decision-making method for direct-navigation ships provided in embodiments of the present invention can provide direct-navigation ships with accurate and reliable collision avoidance strategies, improving the decision-making capabilities and navigation safety of autonomous navigation systems.

[0060] Considering that the encounter time of direct-route ships is relatively short, in a specific embodiment of the present invention, the ship domain model is:

[0061]

[0062]

[0063]

[0064]

[0065]

[0066] Where, is the radius length of the ship area in the positive direction of the X-axis of the ship coordinate system; is the radius length of the ship area in the negative direction of the X-axis of the ship coordinate system; is the radius length of the ship area in the positive direction of the Y axis of the ship coordinate system; is the radius length of the ship area in the negative direction of the Y axis of the ship coordinate system; is the coefficient of gyration diameter; is the ship's advance coefficient; is the captain of a ship; is the ship speed; the ship coordinate system is a coordinate system with the center of gravity of the ship as the origin, the direction pointing to the bow as the positive direction of the X axis, and the direction pointing to the starboard side of the ship as the positive direction of the Y axis.

[0067] It can be seen from the expression of the ship domain model that compared with the conventional ship domain model, the ship domain model in the embodiment of the present invention has doubled the length of each semi-axis except the stern semi-axis to adapt to the shorter encounter time of the direct-navigation ship, thereby improving the adaptability of the ship domain model to the direct-navigation ship.

[0068] In a specific embodiment of the present invention, the minimum safe encounter distance is:

[0069] The safe passing distance for ships is:

[0070] Where, The minimum safe encounter distance; Provide safe passage distance for ships; is the azimuth of the ship.

[0071] In some embodiments of the present invention, the multi-factor risk membership includes closest approach distance membership, closest approach time membership, distance membership, speed ratio membership, relative bearing membership, and ship maneuverability membership; nearest encounter distance membership for:

[0072] Recent encounter time membership for:

[0073] Distance membership for:

[0074] Speed ​​ratio membership for:

[0075] Relative orientation membership for:

[0076] Ship maneuverability membership for:

[0077] Where, DCPA is the distance of closest encounter of ships; TCPA is the time of closest encounter of ships; is the absolute value symbol; is the time of ship collision; Note time for ships; D is the distance between the two ships; k is the speed ratio between the two ships; C To touch the corner; Q is the relative bearing of the two ships; is the ship field coefficient; K is the ship maneuverability coefficient.

[0078] The embodiment of the present invention quantitatively determines the collision risk by comprehensively considering six key indicators, namely, the closest approach distance membership, the closest approach time membership, the distance membership, the speed ratio membership, the relative bearing membership, and the ship maneuverability membership. This eliminates the technical problem of low reliability of a single membership function and achieves accurate prediction of collisions.

[0079] In a specific embodiment of the present invention, the collision risk is:

[0080]

[0081] Where, is the weight of the closest encounter distance membership; is the weight of the membership of the most recent encounter time; is the weight of distance membership; is the weight of the speed ratio membership; is the weight of relative orientation membership; is the weight of the ship's maneuverability membership.

[0082] It should be understood that the weights of the above-mentioned membership degrees can be set or adjusted according to actual application scenarios.

[0083] In a specific embodiment of the present invention, 、 、 、 、 、 They are 0.400, 0.367, 0.133, 0.033 and 0.067 respectively.

[0084] It should be understood that the speed barrier algorithm is a commonly used algorithm in collision avoidance decision-making. Its definition is as follows: If a vessel's speed falls within the speed set defined by the speed barrier algorithm, a collision will occur. In actual maritime operations, the operator must first determine whether their vessel is at risk of collision with another target vessel or obstacle based on the current situation. Only then can appropriate action be taken. Verifying whether the vessel's speed is within the speed barrier zone is part of this assessment. If the vessel's speed is within this range, the conflict must be resolved immediately. Conversely, once the vessel's speed moves outside this zone, the conflict is considered resolved.

[0085] The existing speed barrier set determination process does not consider the ship's maneuverability, which may result in a mismatch between the ship's maneuverability and the speed barrier set, i.e., collision avoidance cannot be achieved. To avoid this, in a specific embodiment of the present invention, the speed barrier set is:

[0086] Where, is the speed obstacle set at the current moment; For the current moment; and are the positions of the two ships at time t; is the radius of the ship's field area; is the distance between the two ships at time t; is the Minkowski operator symbol.

[0087] The embodiment of the present invention takes the ship maneuverability coefficient into consideration in the speed barrier set and optimizes / improves the speed barrier set by considering the ship maneuverability, thereby ensuring the compatibility of the speed barrier set with the ship maneuverability and improving the accuracy and reliability of the speed barrier set.

[0088] To verify the effectiveness of the speed barrier set proposed in the embodiment of the present invention, in a specific embodiment of the present invention, the improved speed barrier algorithm is applied to the intersection encounter scenario. The speed barrier sets obtained by the speed barrier algorithm at t=0, 500, 1000 and 1300 seconds are as follows: Figure 2 shown. Figure 2 The set of speed barriers in is represented by the black area and by Figure 2 It can be seen that the speed barrier intervals for ships vary at different time steps. As the distance decreases, the speed barrier intervals change. These findings demonstrate that the speed barrier method in this embodiment of the present invention can correctly identify encounter scenarios involving ships, consistent with the commonly accepted maritime knowledge of seafarers.

[0089] As can be seen from the foregoing description, in some embodiments of the present invention, the collision risks in the free action phase, the give-way vessel action phase, the direct-route vessel action phase, and the phase where both vessels take action increase step by step. Therefore, in order to accurately determine the ship encounter phase, in some embodiments of the present invention, step S105 is specifically as follows: Determine the first danger threshold of the free action phase, the second danger threshold of the give-way vessel action phase, the third danger threshold of the direct-passage vessel action phase, and the fourth danger threshold of the two-vessel action phase in the four-phase theoretical model; the first danger threshold is smaller than the second danger threshold, the second danger threshold is smaller than the third danger threshold, and the third danger threshold is smaller than the fourth danger threshold; When the collision risk is less than or equal to the first risk threshold, the ship encounter phase is determined to be the free action phase; when the collision risk is greater than the first risk threshold and less than or equal to the second risk threshold, the ship encounter phase is determined to be the give-way ship action phase; when the collision risk is greater than the second risk threshold and less than or equal to the third risk threshold, the ship encounter phase is determined to be the straight-through ship action phase; when the collision risk is greater than the third risk threshold and less than or equal to the fourth risk threshold, the ship encounter phase is determined to be the stage where both ships take action.

[0090] It should be understood that the first risk threshold, the second risk threshold, the third risk threshold, and the fourth risk threshold can be set or adjusted according to actual application scenarios and are not specifically limited here.

[0091] In a specific embodiment of the present invention, the ship maneuvering motion model is:

[0092] Where, T 1. T 2. T 3 is the time constant related to the ship type; K is the ship maneuverability coefficient; is the rudder angle, and its value is ; is the rate of change of the rudder angle; r is the yaw rate; is the acceleration of the yaw rate; is the rate of change of acceleration of the yaw rate.

[0093] The ship maneuvering motion model of the embodiment of the present invention can predict the navigation trajectory under different rudder angles, providing necessary data support for subsequent collision avoidance decision-making plans.

[0094] In order to confirm the validity of the ship maneuvering motion model, simulations were carried out using bulk carriers and oil tankers. The simulation results are shown in Figure 2. Figure 3 As shown, Figure 3The green and blue lines in the figure represent the trajectories of bulk carriers and oil tankers, respectively. The horizontal and vertical coordinates are the two-dimensional trajectory coordinates, respectively. Figure 3 It can be seen from the figure that the maneuvering motion trajectory of the oil tanker is different from that of the bulk carrier. This is because the maneuverability of different ships is different.

[0095] In summary, the collision avoidance decision-making method for straight-line ships provided in the embodiment of the present invention realizes reliable and accurate calculation of collision risk based on multi-factor risk membership, and takes into account the ship maneuverability coefficient when making collision avoidance decisions. It realizes collision avoidance decisions for straight-line ships from multiple aspects such as ship field, collision risk assessment, encounter stage division, ship motion model and collision avoidance decision, and provides meaningful support for the development of autonomous navigation systems in marine environments. This makes up for the avoidance timing and collision avoidance decision-making method for taking action on straight-line ships, ensures the risks caused by the give-way ship not taking action, and improves the safety of smart ships' maritime navigation.

[0096] In order to better implement the direct-line ship collision avoidance decision method in the embodiment of the present invention, based on the direct-line ship collision avoidance decision method, the embodiment of the present invention also provides a direct-line ship collision avoidance decision system, such as Figure 4 As shown, the direct-travel ship collision avoidance decision-making system 400 includes: Basic information acquisition unit 401, used to obtain ship information and navigation environment information in the research waters; The encounter situation determination unit 402 is used to determine the encounter situation between ships based on the ship information and the collision avoidance rules; The ship domain model building unit 403 is used to build a ship domain model of the ship based on the ship information and the navigation environment information, and determine the minimum safe encounter distance and safe passing distance of the ship based on the ship information; a collision risk determination unit 404 for determining a multi-factor risk membership based on the minimum safe encounter distance, the safe ship passing distance, and the ship information, and determining the collision risk of the ship based on the multi-factor risk membership; The ship encounter stage determination unit 405 is used to determine the ship encounter stage based on the collision risk and the four-stage theoretical model. The ship encounter stage includes the free action stage, the give-way ship action stage, the direct-travel ship action stage, and the stage where both ships take action. A collision avoidance responsibility determination unit 406 is configured to determine the collision avoidance responsibility between the ships based on the ship encounter stage and the encounter situation between the ships; The direct-line ship avoidance timing judgment unit 407 is used to determine the direct-line ship avoidance timing based on the encounter situation between the ships, the collision risk, the collision avoidance responsibilities between the ships, and the ship encounter stage; A speed barrier set building unit 408 is configured to obtain a ship maneuverability coefficient of the straight-line ship and build a speed barrier set based on the ship maneuverability coefficient and the trajectory information of the straight-line ship and the give-way ship; The collision avoidance decision unit 409 is used to determine the collision avoidance decision plan of the straight-navigation ship based on the navigation environment information, the speed obstacle set and the ship maneuvering motion model of the straight-navigation ship, and control the straight-navigation ship to navigate according to the collision avoidance decision plan.

[0097] The direct-navigation ship collision avoidance decision system 400 provided in the above embodiment can implement the technical solution described in the above embodiment of the direct-navigation ship collision avoidance decision method. The specific implementation principles of the above modules or units can be found in the corresponding contents in the above embodiment of the direct-navigation ship collision avoidance decision method, which will not be repeated here.

[0098] Those skilled in the art will appreciate that all or part of the process flow of the above-described method embodiment can be implemented by instructing related hardware (such as a processor, controller, etc.) through a computer program, and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0099] The above is a detailed introduction to a direct-navigation ship collision avoidance decision-making method and system provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A collision avoidance decision-making method for a straight-line ship, characterized in that: include: Obtain information on ships and navigation environment in the research waters; Determine the encounter situation between the ships based on the ship information and collision avoidance rules; Building a ship domain model of the ship based on the ship information and the navigation environment information, and determining a minimum safe encounter distance and a safe passing distance of the ship based on the ship information; determining a multi-factor risk membership based on the minimum safe encounter distance, the safe ship passing distance, and the ship information, and determining a collision risk of the ship based on the multi-factor risk membership; Determining the ship encounter phases based on the collision risk and the four-phase theoretical model, wherein the ship encounter phases include a free action phase, a give-way ship action phase, a direct-flowing ship action phase, and a phase where both ships take action; Determine the responsibility for avoiding collision between ships based on the stage of encounter and the situation of encounter between ships; determining a timing for the direct-line vessel to give way based on the encounter situation between the vessels, the collision risk, the collision avoidance responsibilities between the vessels, and the encounter stage; Obtaining a ship maneuverability coefficient of the straight-navigation ship, and constructing a speed barrier set based on the ship maneuverability coefficient and trajectory information of the straight-navigation ship and the give-way ship; A collision avoidance decision plan of the straight-navigation ship is determined based on the navigation environment information, the speed obstacle set and the ship maneuvering motion model of the straight-navigation ship, and the straight-navigation ship is controlled to navigate according to the collision avoidance decision plan.

2. The direct-navigation ship collision avoidance decision-making method according to claim 1, characterized in that: The ship domain model is: Where, is the radius length of the ship area in the positive direction of the X-axis of the ship coordinate system; is the radius length of the ship area in the negative direction of the X-axis of the ship coordinate system; is the radius length of the ship area in the positive direction of the Y axis of the ship coordinate system; is the radius length of the ship area in the negative direction of the Y axis of the ship coordinate system; is the coefficient of gyration diameter; is the ship's advance coefficient; is the captain of a ship; is the ship speed; the ship coordinate system is a coordinate system with the center of gravity of the ship as the origin, the direction pointing to the bow as the positive direction of the X axis, and the direction pointing to the starboard side of the ship as the positive direction of the Y axis.

3. The direct-navigation ship collision avoidance decision-making method according to claim 2, characterized in that: The minimum safe encounter distance is: The safe passage distance for ships is: Where, The minimum safe encounter distance; Provide safe passage distance for ships; is the azimuth of the ship.

4. The direct-navigation ship collision avoidance decision-making method according to claim 3, characterized in that: The multi-factor risk membership includes closest approach distance membership, closest approach time membership, distance membership, speed ratio membership, relative bearing membership and ship maneuverability membership; The closest encounter distance membership for: The nearest encounter time membership for: The distance membership for: The speed ratio membership for: The relative orientation membership for: The ship maneuverability membership for: Where, DCPA is the distance of closest encounter of ships; TCPA is the time of closest encounter of ships; is the absolute value symbol; is the time of ship collision; Note time for ships; D is the distance between the two ships; k is the speed ratio between the two ships; C To touch the corner; Q is the relative bearing of the two ships; is the ship field coefficient; K is the ship maneuverability coefficient.

5. The direct-navigation ship collision avoidance decision-making method according to claim 4, characterized in that: The collision risk is: Where, is the weight of the closest encounter distance membership; is the weight of the membership of the most recent encounter time; is the weight of distance membership; is the weight of the speed ratio membership; is the weight of relative orientation membership; is the weight of the ship's maneuverability membership.

6. The direct-navigation ship collision avoidance decision-making method according to claim 5, characterized in that: The speed barrier set is: Where, is the speed obstacle set at the current moment; For the current moment; and are the positions of the two ships at time t; is the radius of the ship's area; is the distance between the two ships at time t; is the Minkowski operator symbol.

7. The direct-navigation ship collision avoidance decision-making method according to claim 1, characterized in that: The determining of the ship encounter stage based on the collision risk and the four-stage theoretical model includes: determining a first risk threshold for the free action phase, a second risk threshold for the give-way vessel action phase, a third risk threshold for the direct-passage vessel action phase, and a fourth risk threshold for the phase in which both vessels take action in the four-phase theoretical model; the first risk threshold being less than the second risk threshold, the second risk threshold being less than the third risk threshold, and the third risk threshold being less than the fourth risk threshold; When the collision risk is less than or equal to the first risk threshold, the ship encounter phase is determined to be a free action phase; when the collision risk is greater than the first risk threshold and less than or equal to the second risk threshold, the ship encounter phase is determined to be a give-way ship action phase; when the collision risk is greater than the second risk threshold and less than or equal to the third risk threshold, the ship encounter phase is determined to be a straight-through ship action phase; when the collision risk is greater than the third risk threshold and less than or equal to the fourth risk threshold, the ship encounter phase is determined to be a phase in which both ships take action.

8. The direct-navigation ship collision avoidance decision-making method according to claim 1, characterized in that: The responsibility for avoiding collision between ships is determined based on the stage of encounter and the situation of the encounter between ships, including: Determining whether the encounter phase between the vessels is a give-way vessel action phase, a direct-route vessel action phase, or a phase where both vessels take action; If so, when the encounter situation between ships is an overtaking situation, the overtaking ship is the give-way ship and the overtaken ship is the straight-line ship; when the encounter situation between ships is a head-on encounter situation, both ships are give-way ships; when the encounter situation between ships is a crossing encounter, the ship that sees the other ship on the port side is the give-way ship and the ship that sees the other ship on the starboard side is the straight-line ship.

9. The direct-navigation ship collision avoidance decision-making method according to claim 1, characterized in that: The ship maneuvering motion model is: Where, T 1. T 2. T 3 is the time constant related to the ship type; K is the ship maneuverability coefficient; is the rudder angle; is the rate of change of the rudder angle; r is the yaw rate; is the acceleration of the yaw rate; is the rate of change of acceleration of the yaw rate.

10. A collision avoidance decision system for a straight-line ship, characterized in that: include: Basic information acquisition unit, used to obtain ship information and navigation environment information in the research waters; an encounter situation determination unit, configured to determine an encounter situation between ships based on the ship information and collision avoidance rules; a ship domain model construction unit, configured to construct a ship domain model of the ship based on the ship information, and determine a minimum safe encounter distance and a safe passing distance of the ship based on the ship information; a collision risk determination unit, configured to determine a multi-factor risk membership based on the minimum safe encounter distance, the safe ship passing distance, and the ship information, and determine the collision risk of the ship based on the multi-factor risk membership; a ship encounter stage determining unit, configured to determine the ship encounter stage based on the collision risk and a four-stage theoretical model, wherein the ship encounter stage includes a free action stage, a give-way ship action stage, a direct-travel ship action stage, and a stage where both ships take action; A collision avoidance responsibility determination unit, configured to determine the collision avoidance responsibility between the ships based on the ship encounter stage and the encounter situation between the ships; a direct-line ship avoidance timing judgment unit, configured to determine a direct-line ship avoidance timing based on the encounter situation between the ships, the collision risk, the collision avoidance responsibilities between the ships, and the ship encounter stage; a speed barrier set constructing unit, configured to obtain a ship maneuverability coefficient of the straight-routing ship, and construct a speed barrier set based on the ship maneuverability coefficient and the trajectory information of the straight-routing ship and the give-way ship; A collision avoidance decision unit is used to determine a collision avoidance decision plan for the straight-navigation ship based on the navigation environment information, the speed obstacle set and the ship maneuvering motion model of the straight-navigation ship, and control the straight-navigation ship to navigate according to the collision avoidance decision plan.

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