A ship overtaking trajectory planning method based on dynamic field potential field

Abstract

The present invention discloses a ship overtaking trajectory planning method based on a dynamic field potential field. First, a coordinate system is established based on the overtaking ship, the overtaken ship and the channel; an artificial potential field formed by the overtaken ship, the channel boundary and the target point in the overtaking process is established from the perspective of the overtaking ship; whether a sub-target point needs to be set according to the safety field of the overtaken ship is determined, if a sub-target point needs to be set, an artificial potential field formed by the sub-target is established based on the sub-target point, and the artificial potential field formed by the sub-target is replaced by the artificial potential field formed by the target point, based on the artificial potential field formed by the overtaken ship, the channel boundary and the target point (or sub-target), the acceleration of the overtaking ship in the total artificial potential field is calculated, and based on the coordinates and speed of the overtaking ship at the last moment, the coordinates of the overtaking ship are updated in real time to obtain the overtaking planning of the overtaking ship. The present invention takes into account multiple influencing factors of the overtaken ship, the channel boundary and the destination in the ship overtaking scenario, and can realize autonomous real-time planning of the ship overtaking trajectory.

Description

Technical Field

[0001] The present invention relates to the technical field of ship automatic driving, and in particular to a ship overtaking trajectory planning method based on dynamic field potential field. Background Art

[0002] Autonomous driving has many advantages such as reliability, stability and efficiency, which makes the intelligent driving industry have great development potential in the future. With strong support, the intelligent driving industry has developed rapidly in recent years. The development of unmanned ships is relatively late, and most of them are used for scientific operations such as waterway data measurement, hydrological survey, and water quality sampling. Therefore, there is relatively little research on ship autonomous driving, especially the lack of research on automatic collision avoidance methods for ships in civil shipping.

[0003] In particular, due to the special risk judgment model, driving environment, traffic rules and other factors in the process of ship overtaking, the collision avoidance and trajectory planning methods commonly used in automobiles cannot be directly applied to the trajectory planning problem of ship overtaking. Therefore, there is an urgent need for a method that can be applied to ships and can solve the problem of collision avoidance and overtaking trajectory planning in ship automatic driving. Summary of the invention

[0004] In order to address the deficiencies in the prior art, this application proposes a ship overtaking trajectory planning method based on dynamic field potential field, which takes into account multiple influencing factors such as the overtaken ship, channel boundary and destination in the ship overtaking scenario, and can realize autonomous real-time planning of the ship overtaking trajectory.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A ship overtaking trajectory planning method based on dynamic domain potential field comprises the following steps:

[0007] Step 1: Establish a coordinate system based on the channel where the overtaking ship and the overtaken ship are located; obtain the coordinates and speeds of the overtaking ship and the overtaken ship in the coordinate system;

[0008] Step 2: Based on the coordinates and speeds obtained in step 1, artificial potential fields formed by the overtaken ship, the channel boundary, and the target point during the overtaking process are established from the perspective of the overtaking ship;

[0009] Step 3: Determine whether it is necessary to set a sub-target point according to the safety area of ​​the overtaken ship. If it is not necessary to set a sub-target point, go to step 4; if it is necessary to set a sub-target point, establish an artificial potential field formed by the sub-target based on the set sub-target point, and replace the artificial potential field formed by the target point in step 2 with the artificial potential field formed by the sub-target, and then go to step 4;

[0010] Step 4: Calculate the acceleration of the overtaking ship in the total artificial potential field, and update the coordinates of the overtaking ship based on the coordinates and speed of the overtaking ship at the last moment;

[0011] Step 5: Repeat steps 2 to 4 to update the coordinates and speed of the overtaking ship in real time to obtain the overtaking plan of the overtaking ship.

[0012] Furthermore, the artificial potential field formed by the overtaken ship is expressed as:

[0013]

[0014] Among them, k1, k2 and G are all unknown constants greater than zero, M a is the virtual mass of the overtaken ship, R i is the factor affecting the channel conditions at the overtaking ship; a_i is the distance vector between the overtaking ship and the overtaking ship; v a is the speed of the overtaken ship, θ is the speed v of the overtaken ship a Direction and distance vector r a_i The angle between.

[0015] Furthermore, the artificial potential field formed by the channel boundary is expressed as:

[0016]

[0017] Among them, LT a refers to the type of channel where the overtaking ship is located, k3 is a constant greater than zero to be determined, R i is the influencing factor of the channel conditions at the overtaking ship, D is the channel width; r b_i is the distance vector between the channel boundary and the overtaking vessel.

[0018] Furthermore, the artificial potential field formed by the target point is expressed as:

[0019]

[0020] Among them, r α_i is the distance vector between the target point and the overtaking ship, k4 and G α is a constant greater than zero, M α is the virtual mass of the target point, R i Factors that affect the road conditions of the channel where the overtaking ship is located.

[0021] Furthermore, the method of establishing the safety area of ​​the overtaken ship is as follows:

[0022] Calculate the safety area radius of the overtaking ship and the safety area radius of the overtaking ship respectively. The safety area radius R fore It is expressed as follows:

[0023]

[0024] Among them, L is the length of the ship, k ADk is the gain coefficient of the distance AD ​​in the ship turning circle, DT is the gain coefficient of the initial diameter of the gyre DT;

[0025] The longer radius of the safety area of ​​the overtaking ship and the safety area of ​​the overtaken ship is taken as the radius, and a circle is drawn with the coordinates of the overtaken ship as the center to obtain the safety area of ​​the overtaken ship.

[0026] Furthermore, the coefficient k AD and k DT They are respectively expressed as follows:

[0027]

[0028] Where V is the ship speed.

[0029] Furthermore, the basis for determining whether a sub-goal needs to be set is:

[0030] Let R be the radius of the safety zone of the overtaken ship. fore_max , the coordinates of the overtaking ship are marked as (x i ,y i ), the coordinates of the overtaken ship are (x a ,y a );

[0031] When the overtaking vessel needs to overtake the vessel on the right side, if Then there is no need to set a sub-target guidance, otherwise it is necessary to set a sub-target to guide the rear ship to the right side of the front ship; when the overtaking ship needs to overtake from the left side of the overtaken ship, if Then there is no need to set a sub-target guidance, otherwise it is necessary to set a sub-target to guide the rear ship to the left side of the front ship.

[0032] Furthermore, the artificial potential field formed by the sub-goals is expressed as:

[0033]

[0034] Among them, r β_i is the distance vector between the sub-target and the overtaking ship, k4, G β are all unknown constants greater than zero, M β is the virtual mass of the target point, R i It is a factor affecting the condition of the channel where the overtaking ship is located.

[0035] Furthermore, the acceleration in the total artificial potential field is expressed as:

[0036]

[0037] Wherein, F is the force on the overtaking ship in the total artificial potential field, and M is the virtual mass of the overtaking ship.

[0038] Furthermore, the force on the overtaking ship in the total artificial potential field is expressed as:

[0039] F=E·R i exp[-k5v i cos(θ i )]·(1+D i )

[0040] Where E is the sum of the field strengths of the overtaking ship in the total artificial potential field, R i is the influencing factor of the channel condition at the overtaking ship, k5 is an undetermined constant greater than zero, and v i is the speed of the ship; θ i D is the angle between the speed of the overtaking ship and E; i It is a risk factor for ship drivers.

[0041] Beneficial effects of the present invention:

[0042] 1. The present invention expresses the influencing factors in the actual overtaking scene in the form of an artificial potential field and participates in the calculation. The weights of various influencing factors on the model can be updated in real time according to the surrounding environment. It has strong real-time performance and improves the safety of overtaking.

[0043] 2. The present invention enables the ship to have a certain degree of autonomous trajectory planning capability when overtaking, reducing labor costs and the risk of human errors. At the same time, the setting of sub-target points enables the ship to make corresponding changes through human instructions when overtaking autonomously, complying with ship traffic regulations and optimizing the navigation path. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The figure is a flow chart of the overall method of the present invention.

[0045] Figure 2 Schematic diagram of the total artificial potential field distribution in the embodiment.

[0046] Figure 3 Schematic diagram of setting sub-goals in the embodiment. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0048] like Figure 1 , a ship overtaking trajectory planning method based on dynamic field potential field, comprising the following steps:

[0049] Step 1: Establish a coordinate system based on the channel where the overtaking ship and the overtaken ship are located; obtain the coordinates and speeds of the overtaking ship and the overtaken ship in the coordinate system;

[0050] Step 2: Based on the coordinates and speed of the current overtaken ship, an artificial potential field formed by various factors during overtaking is established from the perspective of the overtaking ship; the method for establishing the artificial potential field is as follows:

[0051] Establish an artificial potential field formed by the overtaken ship;

[0052] Calculate the overtaken ship (x a ,y a ) forms a potential field at the overtaking ship (x i ,y i ) is the electric field strength vector E a_i It is expressed as:

[0053]

[0054] Among them, k1, k2 and G are all unknown constants greater than zero, M a is the virtual mass of the overtaken ship, R i It is the place where the ship is overtaken (x i ,y i ) Factors affecting the condition of the waterway; a_i is the distance vector between the overtaken ship and the overtaking ship, denoted as r a_i =(x i -x a ,y i -y a ), v a is the speed of the overtaken ship, θ is the speed v of the overtaken ship a Direction and distance vector r a_i The angle between.

[0055] Establish artificial potential field formed by channel boundary;

[0056] Calculate the potential field formed by the channel boundary when overtaking the ship (x i ,y i ) vector E b_i for:

[0057]

[0058] Among them, LT a refers to the type of channel where the overtaking ship is located, k3 is a constant greater than zero to be determined, R i To overtake the ship (x i ,y i ) is the influencing factor of the channel conditions, D is the channel width; r b_i is the distance vector between the channel boundary and the overtaking ship, denoted as rb_i =(x i -x b ,y i -y b ), (x b ,y b ) represents the coordinates of a point on the boundary of the channel, and y i =y b .

[0059] Establishing an artificial potential field formed by the target point;

[0060] Take a point far enough away and call it the target point (x α ,y α ) to simulate the final destination of the overtaking ship. Consider it as a stationary object, the gravitational potential field it forms is on the overtaking ship (x i ,y i ) vector E α_i for:

[0061]

[0062] Among them, (x α ,y α ) is the coordinate of the target point, r α_i is the distance vector between the target point and the overtaking ship, denoted as r α_i =(x i -x α ,y i -y α ), k4 and G α is a constant greater than zero, M α is the virtual mass of the target point, R i To overtake the ship (x i ,y i ) factors affecting the road conditions of the waterway, E α_i The direction and r α_i is in the same direction as the rising direction of the gradient of the field strength, which represents the influence of the potential field generated by the destination on the overtaking ship.

[0063] Step 3: Since the planning of the trajectory of the overtaking ship during the overtaking process will also be affected by the ship's driving rules, it is necessary to set a sub-target point to induce the overtaking ship to comply with the driving rules and overtake from the designated position of the overtaken ship. In this application, first determine whether it is necessary to set a sub-target point based on the safety field of the overtaken ship. If it is not necessary to set a sub-target point, go to step 4; if it is necessary to set a sub-target point, then establish an artificial potential field formed by the sub-target based on the set sub-target point, and replace the artificial potential field formed by the target point in step 2 with the artificial potential field formed by the sub-target, and then go to step 4.

[0064] More specifically, the method for establishing the safety area of ​​the overtaken ship is:

[0065] Calculate the safety area radius R of the overtaking ship and the overtaken ship respectively fore , the formula is:

[0066]

[0067] Among them, L is the length of the ship, k AD k is the gain coefficient of the distance AD ​​in the ship turning circle, DT is the gain coefficient of the initial diameter of the gyration DT, where the coefficient k AD and k DT It can be calculated by formula (5)

[0068]

[0069] Where V is the ship speed. The longer the ship is, the faster the speed is. The gain coefficient k is AD and k DT This also shows that the size of the safety area increases with the size and speed of the ship.

[0070] The longer of the two is named R fore_max A circle is drawn with this coordinate as the radius and around the coordinates of the overtaken ship as the center, which serves as the simplified safety area of ​​the overtaken ship.

[0071] More specifically, based on the safety area radius R fore_max The method to determine whether a sub-goal needs to be set is as follows:

[0072] The coordinates of the overtaking ship (x i ,y i ), the coordinates of the overtaken ship (x a ,y a ) and the safety zone radius R fore_max When the overtaking vessel needs to overtake the vessel on the right side, Then there is no need to set a sub-target guidance, otherwise it is necessary to set a sub-target to guide the rear ship to the right side of the front ship; when the overtaking ship needs to overtake from the left side of the overtaken ship, if Then there is no need to set a sub-target guidance, otherwise it is necessary to set a sub-target to guide the rear ship to the left side of the front ship.

[0073] More specifically, the method of establishing the artificial potential field formed by the sub-goals is:

[0074] For example, if the overtaking ship needs to overtake from the right side of the overtaken ship, a tangent is drawn through the overtaking ship coordinates to the safe area of ​​the overtaken ship, the right tangent is retained, and the tangent is rotated clockwise around the overtaking ship coordinates by a certain angle (size is Where c is a constant to be determined, r minThe distance from the position of the overtaking ship to the tangent point is obtained, and the endpoint of the line segment is the sub-target point. After obtaining the sub-target, the artificial potential field formed by the target point is removed, and a new gravitational field is obtained at the sub-target to interfere with the original artificial potential field.

[0075] The gravitational potential field formed at the sub-target is overtaking the ship (x i ,y i ) vector E β_i for:

[0076]

[0077] Among them, the coordinates of the sub-target point are (x β ,y β ), r β_i is the distance vector between the sub-target and the overtaking ship, denoted as r β_i =(x i -x β ,y i -y β ); k4, G β are all unknown constants greater than zero, M β is the virtual mass of the target point, R i It is the place where the ship is overtaken (x i ,y i ) Factors affecting the condition of the waterway, E β_i The direction and r β_i is in the same direction as the gradient rising direction of the field strength, which represents the influence of the potential field generated by the sub-target on the overtaking ship.

[0078] Step 4: Calculate the acceleration of the overtaking ship in the total artificial potential field, and update the coordinates of the overtaking ship based on the coordinates and speed of the overtaking ship at the last moment.

[0079] The formula for calculating the force F exerted on the overtaking ship in the total artificial potential field is:

[0080] F=E·R i exp[-k5v i cos(θ i )]·(1+D i ) (7)

[0081] Where E is E a_i , E b_i and E α_i or E β_i In (x i ,y i ) is the sum of the field strengths at i is in (x i ,y i ) channel condition influencing factor, v iis the speed of the ship; θ i D is the angle between the speed direction of the overtaking ship and the direction E; i is the risk factor for the ship driver, the direction of F is the same as that of E, and k5 is an undetermined constant greater than zero.

[0082] Calculate the overtaking ship (x i ,y i ), the formula is:

[0083]

[0084] Wherein, F is the force on the overtaking ship in the total artificial potential field, and M is the virtual mass of the overtaking ship.

[0085] Step 5: Repeat steps 2 to 4 to update the coordinates and speed of the overtaking ship in real time to obtain the overtaking plan of the overtaking ship.

[0086] In order to more clearly illustrate the technical solution of the present invention, this embodiment is introduced as follows in combination with specific data:

[0087] Step 1: This embodiment calculates the force on the overtaking ship in the current situation by setting up an artificial potential field based on the influence of factors such as the overtaken ship, the channel boundary and the destination on the overtaking ship. Figure 3 As shown, it includes the two boundaries of the channel, the overtaking ship and the overtaken ship in the coordinate system. The channel width is 300m, the channel boundary is parallel to the y-axis, the horizontal coordinates are -150 and 150 respectively, the overtaking ship coordinates are (0, -50), the overtaking ship coordinates are (20, 50), the overtaking ship and the overtaken ship are both 20m long, the speed of both ships is 20km / h, and the speed direction of both ships is along the positive direction of the y-axis. In this example, it is assumed that the overtaking ship should overtake the overtaken ship from the right side.

[0088] Step 2: After acquiring the data, establish an artificial potential field formed by various factors during overtaking from the perspective of the overtaking ship, as follows:

[0089] Calculate the virtual mass of the overtaken ship;

[0090]

[0091] Where m a =5×10 4 is the mass of the overtaken ship, T a =1×10 -4 is the type of the overtaken ship, α=1, β=1 are both unknown constants.

[0092] Calculate the field strength of the artificial potential field formed by the overtaking ship at the position of the overtaking ship;

[0093] Calculate the potential field formed by the overtaken ship at (40,50) and the field strength vector E at (20,-50) a_i , expressed as:

[0094]

[0095] Among them, k1, k2 and G are all unknown constants greater than zero. In this embodiment, they are respectively k2=1,G=150;M a =100 is the virtual mass of the overtaken ship, R i =1 is the influencing factor of the channel condition at (20, -50); r a_i =(-20,-100) is the distance vector between the two ships, v a =20 is the speed of the overtaken ship; θ = 68.2° is v a With r a_i The angle between directions.

[0096] Calculate the field strength of the artificial potential field formed by the channel boundary at the position of the overtaking ship;

[0097] Calculate the potential field formed by the left boundary of the channel at (20, -50) and the field strength vector E b_i_L :

[0098]

[0099] Among them, LT a refers to the type of channel where the overtaking ship is located, k3=1 is a constant greater than zero, R i =1 is the influencing factor of the channel condition at (20, -50), D = 300 is the channel width, r b_i =(130,0) is the distance vector between the channel boundary and the center of mass of the overtaking ship. Similarly, the field strength vector E of the potential field formed by the right boundary of the channel at (20,-50) can be obtained. b_i_R :

[0100]

[0101] The strength of the artificial potential field formed by the channel boundary at the position of the overtaking ship is

[0102] E b_i =E b_i_L +E b_i_R =(-15.58,0)+(-15.58,0)=(-31.16,0) (13)

[0103] Calculate the virtual mass M of the target point α ;

[0104]

[0105] Where m α =1×10 6 is the mass of the target point, T α =4×10 -4 is the type of the target point, v α =20 is the speed of the target point, α=1, β=1, which are all unknown constants.

[0106] Calculate the field strength of the artificial potential field formed by the target point at the position of the overtaking ship;

[0107] The vector E of the gravitational potential field formed by the target point at (20, -50) α_i for

[0108]

[0109] The coordinates of the target point are (0,20), r α_i =(-20,250) is the distance vector, G α =100 is a constant greater than zero, M α =800 is the virtual mass of the target point, R i =1 is the factor affecting the road condition of the waterway at (20,-50).

[0110] Step 3: Optimize the overtaking path through sub-target points. First, determine whether it is necessary to set sub-target points based on the safety area of ​​the ship being overtaken. If it is not necessary to set sub-target points, go to step 4. If it is necessary to set sub-target points, establish an artificial potential field formed by sub-targets based on the set sub-target points, and replace the artificial potential field formed by the target points in step 2 with the artificial potential field formed by the sub-targets, and then go to step 4.

[0111] Step 3.1, establish the safety area of ​​the overtaken ship;

[0112] Calculate the gain coefficient k of the distance AD ​​in the turning circle of the overtaking ship and the overtaken ship respectively AD_1 and k AD_2 , the gain coefficient k of the initial turning radius DT of the overtaking ship and the overtaken ship DT_1 and k DT_2 :

[0113]

[0114] Calculate the safety area radius R of the overtaking ship and the overtaken ship respectively fore_1 and R fore_2

[0115]

[0116] The longer of the two is named Rfore_max A circle is drawn with this coordinate as the radius and around the coordinates of the overtaken ship as the center, which serves as the simplified safety area of ​​the overtaken ship.

[0117] Step 3.2: Determine whether to set sub-goals;

[0118] Given the coordinates of the overtaking ship (20, -50), the coordinates of the overtaking ship (40, 50), and the radius of the safety zone R fore_max =66.60m. x i =20m, because Therefore, it is necessary to set sub-goal guidance.

[0119] Step 3.3, establish the artificial potential field formed by the sub-goals;

[0120] Draw a tangent line through the coordinates of the overtaking ship to the safe area of ​​the overtaken ship, keep the right tangent line, get the tangent point (24.85, -25.73), rotate the tangent line clockwise around the coordinates of the overtaking ship by a certain angle (size is Where c = 100 is a constant to be determined, r min =77.22m is the distance from the position of the overtaking ship to the tangent point), and the endpoint of the obtained line segment is the sub-target point (54.27, -34.12).

[0121] Step 3.4: Calculate the virtual mass M of the sub-target point β ;

[0122]

[0123] Where m β =1×10 5 is the quality of the sub-target point, T β =4×10 -4 is the type of the sub-target point, v β =20 is the speed of the sub-target point, α=1, β=1 are both unknown constants.

[0124] Step 3.5: Calculate the potential field formed by the sub-target

[0125] After obtaining the sub-target, remove the artificial potential field formed by the target point and obtain a new gravitational field at the sub-target.

[0126]

[0127] The coordinates of the sub-target point are (54.27, -34.12), r β_i =(-24.27,15.88) is the distance vector, G β =100 is a constant greater than zero, M β=80 is the virtual mass of the sub-target point, R i =1 is the factor affecting the road condition of the waterway at (20,-50).

[0128] The potential field of the sub-target point is used to replace the potential field of the target point, and the optimized force situation of the overtaking ship is obtained.

[0129] Step 4: Calculate the acceleration of the overtaking ship in the total artificial potential field, and update the coordinates of the overtaking ship based on the coordinates and speed of the overtaking ship at the last moment.

[0130] Step 4.1: Calculate the driver’s risk factor D i ;

[0131] D i =η1D1+η2D2+η3D3+η4D4=2.5×0.2+1×0.2+2×0.1+0.2×0.5=1 (22)

[0132] Among them, D1=2.5 is the driver's physiological and psychological risk factor, D2=1 is the driver's cognitive risk factor, D3=2 is the driver's skill risk factor, and D4=0.2 is the driver's illegal risk factor; η1=0.2, η2=0.2, η3=0.1, η4=0.5 are the weight coefficients of each factor.

[0133] Step 4.2, calculate the force on the overtaking ship;

[0134] Since the sub-goal was introduced in step 2.1, the target point potential field is replaced by the sub-goal potential field in this step, and the force situation of the overtaking ship is as follows:

[0135]

[0136] Where E = (154.79, -65.57) is E a_i , E b_i and E β The sum of the field strengths at (20, -50), R i is the channel condition influencing factor at (20, -50), is an unknown constant greater than zero, v i =20 is the speed of the overtaking ship, θ i =16.16° is the angle D between the speed direction of the overtaking ship and the direction E i =1 is the risk factor for the ship driver, and the direction of F is the same as that of E.

[0137] Step 4.3, calculating the virtual mass of the overtaking ship;

[0138] M=M(m,T,v)=Tm(1+αv β ) = 2 × 10 -4×1×105(1+200)=40 (24)

[0139] Where m = 1 × 10 5 is the mass of the overtaking ship, T = 2 × 10 -4 is the type of overtaking ship, α=1, β=1 are both unknown constants.

[0140] Step 4.4, calculate the acceleration of the overtaking ship;

[0141]

[0142] Where F is the force condition of the overtaking ship at (20, -50), and M = 40 is the virtual mass of the overtaking ship.

[0143] Thus, the acceleration of the overtaking ship at this moment can be obtained. Similarly, the acceleration of the overtaking ship at the next moment can be calculated to achieve the result of planning the ship's overtaking trajectory.

[0144] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A ship overtaking trajectory planning method based on dynamic field potential field, characterized in that: The steps include: Step 1: Establish a coordinate system based on the channel where the overtaking ship and the overtaken ship are located; obtain the coordinates and speeds of the overtaking ship and the overtaken ship in the coordinate system; Step 2: Based on the coordinates and speeds obtained in step 1, artificial potential fields formed by the overtaken ship, the channel boundary, and the target point during the overtaking process are established from the perspective of the overtaking ship; Step 3: Determine whether it is necessary to set a sub-target point according to the safety area of ​​the overtaken ship. If it is not necessary to set a sub-target point, go to step 4; if it is necessary to set a sub-target point, establish an artificial potential field formed by the sub-target based on the set sub-target point, and replace the artificial potential field formed by the target point in step 2 with the artificial potential field formed by the sub-target, and then go to step 4; Step 4: Calculate the acceleration of the overtaking ship in the total artificial potential field, and update the coordinates of the overtaking ship based on the coordinates and speed of the overtaking ship at the last moment; Step 5, repeating steps 2 to 4, updating the coordinates and speed of the overtaking ship in real time to obtain the overtaking plan of the overtaking ship; The artificial potential field formed by the overtaken ship is expressed as: Among them, k1, k2 and G are all unknown constants greater than zero, M a is the virtual mass of the overtaken ship, R i is the factor affecting the channel conditions at the overtaking ship; a_i is the distance vector between the overtaking ship and the overtaking ship; v a is the speed of the overtaken ship, θ is the speed v of the overtaken ship a Direction and distance vector r a_i The angle between.

2. A ship overtaking trajectory planning method based on dynamic domain potential field according to claim 1, characterized in that: The artificial potential field formed by the channel boundary is expressed as: Among them, LT a refers to the type of channel where the overtaking ship is located, k3 is a constant greater than zero to be determined, R i is the influencing factor of the channel conditions at the overtaking ship, D is the channel width; r b_i is the distance vector between the channel boundary and the overtaking vessel.

3. The ship overtaking trajectory planning method based on dynamic domain potential field according to claim 1 is characterized in that: The artificial potential field formed by the target point is expressed as: Among them, r α_i is the distance vector between the target point and the overtaking ship, k4 and G α is a constant greater than zero, M α is the virtual mass of the target point, R i Factors that affect the road conditions of the channel where the overtaking ship is located.

4. A ship overtaking trajectory planning method based on dynamic domain potential field according to claim 1, characterized in that: The method of establishing a safe area for the overtaken vessel is: Calculate the safety area radius of the overtaking ship and the safety area radius of the overtaking ship respectively. The safety area radius R fore It is expressed as follows: Among them, L is the captain, k AD k is the gain coefficient of the distance AD ​​in the ship turning circle, DT is the gain coefficient of the initial diameter of the gyre DT; The longer radius of the safety area of ​​the overtaking ship and the safety area of ​​the overtaken ship is taken as the radius, and a circle is drawn with the coordinates of the overtaken ship as the center to obtain the safety area of ​​the overtaken ship.

5. A ship overtaking trajectory planning method based on dynamic domain potential field according to claim 4, characterized in that: Coefficient k AD and k DT They are respectively expressed as follows: Where V is the ship speed.

6. A ship overtaking trajectory planning method based on dynamic domain potential field according to claim 4, characterized in that: The basis for determining whether to set sub-goals is: Let R be the radius of the safety zone of the overtaken ship. fore_max , the coordinates of the overtaking ship are marked as (x i ,y i ), the coordinates of the overtaken ship are (x a ,y a ); When the overtaking vessel needs to overtake the vessel on the right side, if Then there is no need to set a sub-target guidance, otherwise it is necessary to set a sub-target to guide the rear ship to the right side of the front ship; when the overtaking ship needs to overtake from the left side of the overtaken ship, if Then there is no need to set a sub-target guidance, otherwise it is necessary to set a sub-target to guide the rear ship to the left side of the front ship.

7. A ship overtaking trajectory planning method based on dynamic domain potential field according to claim 6, characterized in that: The artificial potential field formed by the sub-goals is expressed as: Among them, r β_i is the distance vector between the sub-target and the overtaking ship, k4, G β are all unknown constants greater than zero, M β is the virtual mass of the target point, R i It is a factor affecting the condition of the channel where the overtaking ship is located.

8. The ship overtaking trajectory planning method based on dynamic domain potential field according to claim 1 is characterized in that: The acceleration in the total artificial potential field is expressed as: Wherein, F is the force on the overtaking ship in the total artificial potential field, and M is the virtual mass of the overtaking ship.

9. A ship overtaking trajectory planning method based on dynamic domain potential field according to claim 8, characterized in that: The force on the overtaking ship in the total artificial potential field is expressed as: F=E·R i ·exp[-k5v i cos(θ i )]·(1+D i ) Where E is the sum of the field strengths of the overtaking ship in the total artificial potential field, R i is the influencing factor of the channel condition at the overtaking ship, k5 is an undetermined constant greater than zero, and v i is the speed of the ship; θ i D is the angle between the speed of the overtaking ship and E; i It is a risk factor for ship drivers.

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