CN-121977558-A - Ship dynamic window local path planning method integrating navigation rules

CN121977558ACN 121977558 ACN121977558 ACN 121977558ACN-121977558-A

Abstract

The invention provides a ship dynamic window local path planning method integrating navigation rules, which belongs to the technical field of intelligent path planning and mainly comprises the steps of constructing a ship kinematic model, carrying out speed sampling, screening sampling speeds, retaining effective speed combinations without collision risks, carrying out motion simulation on the screened effective speed combinations based on the kinematic model to generate a plurality of simulation paths, constructing a situation judgment function, judging meeting situations through relative azimuth and heading difference values, constructing a risk function, judging the risk degree between a ship and an obstacle, locking the meeting situations, constructing an evaluation function in a dynamic window method, obtaining the scoring results of the simulation paths, comparing the scoring results of all the simulation paths, and selecting a ship running path of the next time step. The method has high efficiency, stability and accuracy when processing complex dynamic meeting scenes, and can provide reliable path planning support for autonomous navigation safety and intelligent decision-making of the ship.

Inventors

ZHAO XINHAO
QIN MING
HUI ZHIPENG
CHEN GANG
ZHENG JIANBO
WANG ZIHAO
NI XINYU
LI ZHIPENG
LIU SHITONG

Assignees

浙江省智能船舶研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20260113

Claims (10)

1. A marine vessel dynamic window local path planning method integrating navigation rules is characterized by comprising the following steps: Step1, constructing a kinematic model of a ship; Step 2, speed sampling screening is carried out, sampling speeds are screened by a speed barrier method, and effective speed combinations without collision risk are reserved; Step 3, constructing COLREGs situation judgment functions based on the generated multiple simulation paths, and judging the meeting situation through the relative azimuth and heading difference values; step 4, constructing a risk function for judging the risk degree between the ship and the obstacle and locking the meeting situation according to the risk degree; Step 5, based on the risk degree and according to the risk degree locking meeting situation, constructing an evaluation function in a dynamic window method, setting weight parameters of each evaluation function, and obtaining a scoring result of the simulation path; and 6, comparing the scoring results of all the simulation paths, and selecting the ship running path of the next time step based on the comparison result.
2. The method for planning a local path of a dynamic window of a ship fused with a navigation rule according to claim 1, wherein the kinematic model is an arc model, and the speed space is limited by three constraints, namely a maximum and minimum speed constraint, a dynamic constraint and a safety constraint.
3. The method for planning a local path of a dynamic window of a ship fused with navigation rules according to claim 1, wherein in the step 2, speed sampling is performed according to fixed angular speed intervals, and speed screening is performed by screening out speeds which collide at set time by using a speed barrier method, wherein the speed is represented by the following formula: Wherein: For a set of speeds that would collide in a certain time in the future as derived from the speed obstacle method, For the absolute speed of the present vessel, At relative speed for the ship A lower motion trail region is provided, and a lower motion trail region is provided, For the expansion circle of the ship, For the speed of the present vessel, Is the relative speed.
4. The method for planning the local path of the dynamic window of the ship fused with the navigation rule according to claim 1, wherein the specific process of the step3 comprises the following steps: s31, calculating the relative azimuth, namely calculating the relative position of the ship based on the ship and the relative position of the ship based on the ship by using the position information of the ship and the position information of the obstacle ship; S32, calculating a course difference value, namely calculating the course difference value between the ship and the other ship by using the course information; S33, establishing COLREGs situation judgment functions, namely establishing the situation judgment functions according to the relative azimuth information, the heading difference information and the COLREGs rule, wherein the situation judgment functions are shown in the following formula: Wherein: The azimuth angle of the ship relative to the ship; is the azimuth angle of the own ship relative to the other ship; the heading difference of the two ships is; the speed of the ship is kept; the maximum navigational speed of the ship is set; is the most recently encountered time.
5. The method for planning a local path of a dynamic window of a ship fused with a navigation rule according to claim 1, wherein the constructing a risk function in the step4 is specifically: calculating a nearest encounter distance CPA and a nearest encounter time based on encounter situations ; According to CPA, Setting a threshold value to obtain a risk function The following formula is shown: Wherein: For the type of encounter currently being calculated, The distance that is encountered in the recent past, Is the most recently encountered time.
6. The method for planning the local path of the dynamic window of the ship fused with the navigation rule according to claim 5, wherein the locking meeting situation in the step4 is specifically: By setting a state machine based on the risk degree, the meeting situation is kept constant according to the risk degree and the change of the meeting situation, and the following formula is shown: Wherein: For the type of encounter currently being calculated, For the last locked encounter situation, Is the risk level of the last lock.
7. The method for planning a local path of a dynamic window of a ship fused with a navigation rule according to claim 1, wherein in the step 5, an evaluation function in the dynamic window method is constructed based on the risk degree and locking the meeting situation according to the risk degree The method specifically comprises the following steps: Wherein: as a function of the cost of the object, In order to be a cost function of the obstacle, A cost function is COLREGs rule; The target cost function is designed according to the difference value of the distance between the first track point predicted by the ship and the target point reached by the last target predicted by the ship; the obstacle cost function is designed by combining a Logistic function according to the minimum distance from the predicted track point of the ship to the obstacle; And the COLREGs rule cost function is used for designing the cost according to the COLREGs rule and the obtained meeting situation.
8. The method for planning a local path of a dynamic window of a ship fused with a navigation rule according to claim 7, wherein the objective cost function is represented by the following formula: Wherein: As a weight for the cost of the goal, Is the direction angle of the target point, Is the course angle of the ship.
9. The method for planning a local path of a dynamic window of a ship fused with a navigation rule according to claim 7, wherein the cost function of the obstacle is represented by the following formula: Wherein: In order to weight the cost of the obstacle, In order to predict the distance of the trajectory from the obstacle, For the net safe distance of the trajectory point from the dynamic obstacle, Representing the steep coefficients of the Logistic function.
10. The method for planning a local path of a dynamic window of a ship fused with a navigation rule according to claim 7, wherein the COLREGs rule cost function is represented by the following formula: Wherein: For the weight of COLREGs rule costs, At the expense of the obstacle, In the meeting situation of the ship and the obstacle, In order to change the course of the ship itself, Is the nearest meeting distance of the string and the obstacle.

Description

Ship dynamic window local path planning method integrating navigation rules Technical Field The invention belongs to the technical field of intelligent path planning, and particularly relates to a ship dynamic window local path planning method fusing navigation rules. Background With the development of artificial intelligence and ship automation technology, intelligent ships are increasingly widely applied in multiple scenes. In autonomous navigation, the existence of single-ship barriers brings serious challenges to local path planning, the scene is required to strictly follow the international maritime collision avoidance regulations (COLREGs), and the dependence of the multi-barrier scene on the regulations is low. The path rules are divided into global and local categories. The global path planning focuses on the optimal whole route, is suitable for the known static ocean environment, and the local path planning focuses on the real-time collision avoidance decision in the dynamic environment, and the decision core of the single ship meeting scene is COLREGs rules. In a typical local path planning algorithm, an artificial potential field method is easy to fall into local optimum, and COLREGs rules are not integrated, so that the requirement of single-ship collision avoidance compliance cannot be met. The dynamic window method (DWA) has high calculation efficiency and simple logic, and the static scene has good performance, but under the single-ship dynamic scene, the rule requirements on different situations such as meeting, overtaking and the like cannot be adapted because COLREGs rule rules are not fused deeply, and the collision avoidance decision compliance safety is difficult to ensure. In recent years, the improved multi-focus evaluation function optimization or environmental adaptability improvement aiming at DWA is still not solved for the rule fusion core problem. Most of the improvements do not take COLREGs rules as core constraints, and part of the rules are not modeled in a refined mode although the rules are mentioned, so that a single ship collision avoidance path conforming to the rules cannot be output. In recent years, aiming at the improvement of a dynamic window method, multi-focus evaluation function optimization or environmental adaptability improvement still has key limitations that on one hand, COLREGs rules are not used as core constraint depth to be integrated into planning logic, on the other hand, partial improvement is not used for carrying out detailed modeling while the rules are mentioned, so that a generated single ship collision prevention path is difficult to completely meet the rule requirements, on the other hand, the speed association risk of a long-distance dynamic obstacle is insufficient, the traditional DWA relies on a path simulation detection collision with a limited time step, the motion trend of the long-distance obstacle is perceived with lag, the sampling speed is easy to cause short-distance collision prevention space shortage because the track of the long-distance obstacle is not avoided in advance, and a situation locking mechanism combining the risk degree is lacking, so that situation deviation is easy to be caused when the obstacle is in motion mutation, the continuity of decisions is destroyed, and the real-time performance and safety of local planning are influenced. Disclosure of Invention The method for planning the local path of the ship solves the technical problems that under a single-ship obstacle scene, the conventional method for planning the local path of the ship does not deeply merge COLREGs rule core constraints, can not output a collision avoidance path aiming at meeting situations such as opposite meeting, overtaking, crossing meeting and the like, is insufficient in speed-related risk pre-judgment on a remote dynamic obstacle, is easy to cause insufficient short-distance collision avoidance space due to the fact that a motion track of the remote dynamic obstacle is not avoided in advance, and is easy to cause situation deviation and damaged decision continuity in collision avoidance due to lack of a situation locking mechanism combined with risk, and finally causes double defects of single-ship collision avoidance compliance and safety, so that the actual requirement of autonomous navigation of an intelligent ship is difficult to be met. Aiming at the problems, the invention provides a ship dynamic window local path planning method fusing navigation rules, which comprises the following steps: Step1, constructing a kinematic model of a ship; Step 2, speed sampling screening is carried out, sampling speeds are screened by a speed barrier method, and effective speed combinations without collision risk are reserved; Step 3, constructing COLREGs situation judgment functions based on the generated multiple simulation paths, and judging the meeting situation through the relative azimuth and heading difference values; step 4, constructing a ri