A ship zigzag navigation guidance and control method based on line-of-sight guidance

Abstract

The application discloses a ship Z-shaped navigation guidance and control method based on line-of-sight guidance, and belongs to the technical field of water surface ship transportation under severe sea conditions, and comprises the following steps: establishing a ship motion mathematical model; adding a wind and wave disturbance factor in the ship motion mathematical model to obtain a ship motion model under severe sea conditions; adopting a third-order closed-loop gain shaping algorithm to design a preliminary controller; introducing a nonlinear composite function into the preliminary controller to realize ship course keeping control, and combining a nonlinear feedback and a nonlinear embedding method to optimize the preliminary controller to obtain a final controller; designing a Z-shaped navigation guidance strategy based on the line-of-sight guidance algorithm, so that the ship navigates along a Z-shaped route under severe sea conditions; and adjusting a new course distance to adjust a route point, which is used to make the ship quickly return to a planned route when the severe sea conditions are recovered to normal sea conditions. The application has influence on improving the safety, reliability and intelligence of the ship.

Description

Technical Field

[0001] This invention belongs to the field of surface vessel transportation technology under adverse sea conditions, and particularly relates to a guidance and control method for zigzag navigation of ships based on line-of-sight guidance. Background Technology

[0002] With the continuous development of global trade and maritime transport, the shipping industry plays an increasingly important role in the global economy. As a primary means of cargo transportation, the safety of ships during navigation has always been a core concern within the industry. During ocean voyages, if a ship encounters severe storms and cannot find a suitable anchorage, it may face a series of serious problems, including violent rolling, bottoming, deck flooding, stern submersion, reduced speed, and course instability. These problems not only cause difficulties in ship handling but can also lead to more serious consequences, such as structural damage or even capsizing. In such adverse sea conditions, traditional autopilot systems typically perform frequent large rudder angle adjustments to cope with wave interference. This high-frequency operation not only increases equipment wear and energy consumption but may also further increase the probability of accidents. Due to safety requirements, manual steering is usually switched from autopilot to manual steering. However, prolonged manual steering in adverse sea conditions puts crew members in a state of high stress and fatigue, greatly increasing the risk of operational errors and further threatening the safety of the ship and its cargo. Therefore, how to achieve autonomous and precise motion control of ships in adverse sea conditions to ensure navigation safety is not only an important issue in ensuring shipping efficiency, but also a core challenge that needs to be addressed in the field of shipbuilding engineering, especially in the development of MASS (Maritime Autonomous Surface Ships) technology.

[0003] Several feasible research methods exist, such as the patent CN202510089839.5, which discloses a method and system for underwater vehicle formation control based on LOS constraints. The method includes the following steps: establishing a mathematical model for underwater vehicle formation control; defining the tracking error of the formation based on the mathematical model, and designing an obstacle Lyapunov function to handle line-of-sight constraints; designing an adaptive integral guidance strategy with LOS constraints under local communication, while ensuring connectivity and safety; constructing a finite-time observer to fit the disturbance variables in the model, and using the fitted approximation to compensate for the system's control input; designing a constrained formation controller based on the adaptive integral guidance strategy and the finite-time observer to achieve underwater vehicle formation control with LOS constraints under local communication. Simultaneously, the constraints of the sensor's field of view angle are considered to improve the stability and accuracy of the formation control. Patent CN202311549793.8 discloses a design method for a fishing vessel track-keeping controller considering adverse sea conditions. The method includes the following steps: designing a fishing vessel track-keeping controller considering adverse sea conditions; applying an integral separation method to control the fishing vessel track-keeping controller; designing a control law based on the designed fishing vessel track-keeping controller; and designing a nonlinear function based on the designed control law. An indirect track-keeping controller is designed for fishing vessels, effectively handling the influence of the integral term on the control system and balancing the system control energy. The tracking accuracy of track-keeping is improved under the interference of adverse sea conditions, meeting the requirements of the control system for stability, accuracy, and safety. The designed controller, combining a nonlinear feedback control algorithm based on a sine function and an improved closed-loop gain shaping algorithm, overcomes the structural characteristics of traditional unity feedback systems and the inherent characteristics of large inertia and long time delays of fishing vessels, achieving energy optimization at the controller input.

[0004] The above research methods are beneficial to improving the control effect of wind and waves on the ship's course or track maintenance and path tracking performance, but they do not reduce the ship's rolling degree or alleviate the impact of waves. Large winds and waves can still pose a danger to the ship itself. Summary of the Invention

[0005] Existing research methods have failed to achieve autonomous and precise motion control of ships in adverse sea conditions, thus hindering navigational safety. Ships may face a series of serious problems, including severe rolling motions, bottoming out, deck flooding, stern submersion, decreased speed, and course instability. These problems not only cause difficulties in ship handling but may also lead to more serious consequences, such as structural damage or even capsizing. The technical means employed in this invention are as follows: a line-of-sight guided Z-shaped navigation guidance and control method for ships, comprising the following steps:

[0006] S1. Establish a mathematical model of ship motion;

[0007] S2. Add wind and wave interference factors to the mathematical model of ship motion to obtain the ship motion model under severe sea conditions;

[0008] S3. Based on the ship motion model under severe sea conditions, a preliminary controller is designed using a third-order closed-loop gain shaping algorithm.

[0009] S4. Introduce a nonlinear composite function into the preliminary controller to achieve course-keeping control of the ship. Then, combine nonlinear feedback and nonlinear embedding methods to optimize the preliminary controller and obtain the final controller.

[0010] S5. A "Z" shaped navigation guidance strategy was designed based on the line-of-sight guidance algorithm, enabling the ship to navigate along a "Z" shaped route in adverse sea conditions.

[0011] S6. Adjust waypoints using new course distances to enable vessels to quickly return to their planned routes when returning from severe sea conditions to normal sea conditions.

[0012] Furthermore, the process of designing a preliminary controller based on a ship motion model under severe sea conditions using a third-order closed-loop gain shaping algorithm is as follows:

[0013] The nonlinear form of the mathematical model for ship motion is:

[0014] (1)

[0015] in: The acceleration of the bow angle is the angular velocity of the bow. The turning angular velocity, As the rudder angle, , All are ship maneuverability indices. A , B It is a nonlinear parameter;

[0016] By linearizing the second-order nonlinear ship model in equation (1), we obtain the transfer function of the second-order linear ship model:

[0017] (2)

[0018] Let the bandwidth frequency of the closed-loop system be... The closed-loop system includes a final controller and a ship motion model; then the complementary sensitivity function of the ship's heading-keeping control system is... That is, the closed-loop transfer function of the closed-loop system is shown in equation (3), where As the controlled object, For the controller:

[0019] (3)

[0020] The initial controller is then given by equation (4):

[0021] (4)

[0022] in: The bandwidth frequency set for the closed-loop system. It is a constant. For the Laplace operator.

[0023] Furthermore, the aforementioned wind and wave interference factors are characterized using a Beaufort scale 6 wind wave interference model and a Beaufort scale 8 wind wave interference model.

[0024] The expression for the wave disturbance model of Beaufort scale 6 wind is as follows:

[0025] (5)

[0026] The expressions for the wave disturbance model of Beaufort scale 8 wind are as follows:

[0027] (6)

[0028] in, It is Gaussian white noise. For the Laplace operator, This is due to high-frequency sea wave interference.

[0029] Furthermore: the nonlinear composite function The expression is as follows:

[0030] (7)

[0031] in: These are the coefficients of a nonlinear composite function. It is a variable.

[0032] Furthermore, the nonlinear feedback and nonlinear embedding expressions in the final controller are as follows:

[0033] Nonlinear feedback :

[0034] (8)

[0035] Nonlinear embedding :

[0036] (9)

[0037] in: , For ship maneuverability index, It is a constant;

[0038] By organically integrating nonlinear feedback and nonlinear embedding, the final controller is obtained.

[0039] Furthermore: The line-of-sight guidance algorithm is based on the line-of-sight angle between the target and the ship. It uses sensors to measure the deviation information between the ship's current position, heading, and preset path in real time, and then generates corresponding control commands to guide the ship to sail along the predetermined route. The specific process is as follows:

[0040] Let the current position coordinates of the ship in the geodetic coordinate system be... , , , ……, The planned tracking points are the first waypoint, the second waypoint, and so on. One waypoint, , The route segment currently planned for tracking requires two steps to achieve tracking control:

[0041] First, determine the trajectory error. This updates the position of the tracked target: the target position is a constant determined by the ship's performance at a distance from the vertical foot. Location, based on the coordinates of the target point The ship's expected course is updated in real time. Looking for new The process continued until the ship reached The heading angle of the tracked route segment in the geodetic coordinate system is expressed as: :

[0042] (10)

[0043] in: The ordinate of the second waypoint. The ordinate of the first waypoint. The x-coordinate of the second waypoint The x-coordinate of the second waypoint;

[0044] In path tracking, longitudinal error and lateral error represent the degree to which the current point deviates from the reference path, as follows:

[0045] (11)

[0046] in: The ship's current position. To track the closest point on the flight path; The x-coordinate represents the distance of the current ship's position from the starting point. The vertical coordinate represents the distance of the current ship's position from the starting point;

[0047] Rotation matrix Used to convert from a geodetic coordinate system to a path coordinate system for easier representation of errors, as follows:

[0048] (12)

[0049] Substituting the rotation matrix into the error formula (11), we get:

[0050] (13)

[0051] When expanded, it appears as follows:

[0052] (14)

[0053] (15)

[0054] The ship is expected to converge to the viewpoint quickly and stably. And continue to track along the path, with the expected bow of the ship pointing towards for:

[0055] (16)

[0056] Furthermore: The process of adjusting waypoints using the new course distance to enable vessels to quickly return to their planned routes when returning from severe sea conditions to normal sea conditions is as follows:

[0057] The intersection of the "Z" shaped route and the planned route is marked as follows: The intersection points are the first intersection point, the second intersection point, the third intersection point, and so on. One intersection point;

[0058] The apex of the "Z" shaped flight path is the turning point where the course changes angle, marked as... These are respectively the first turning point, the second turning point, the third turning point... Turning point;

[0059] Assumption If the coordinates are the current intersection point, then the next intersection point... The calculation formula is:

[0060] (17)

[0061] (18)

[0062] in: Yaw distance, or the lateral deviation distance in a "Z" shape, is set based on the intensity of wind and waves and the ship's performance. It is the bow of the ship that is affected by the waves. The heading angle of the planned route; It is the x-coordinate of the next intersection point. It is the ordinate of the next intersection point; It is the x-coordinate of the current intersection point. The ordinate of the current intersection point;

[0063] when When the vertex coordinates are odd, The calculation formula is:

[0064] (19)

[0065] (20)

[0066] in: It is the x-coordinate of the vertex. It is the ordinate of the vertex;

[0067] when When the number is even, the vertex coordinates The calculation formula is:

[0068] (twenty one)

[0069] (twenty two)

[0070] If the wind and waves decrease and return to normal sea conditions, when the ship passes the apex... Next intersection point Then, continue sailing along the "Z" shaped route until the ship reaches the next intersection. Directly switch to the planned route.

[0071] Move the current ship position forward by the "new course distance" as the turning point, and set the next intersection point as the turning point. Set as the return route point;

[0072] New course distance The method for obtaining it is as follows:

[0073] (twenty three)

[0074] in: It is the cyclicity index; It is a follower index; It is the initial velocity of the rotation; It is the rudder angle; It is the reversal angle; When steering, the rudder angle changes from normal to... Time required;

[0075] Assumption These are the coordinates of the current ship position. If it is the current heading, then the new turning point The calculation formula is as follows:

[0076] (twenty four)

[0077] (25)

[0078] in: It is the x-coordinate of the new turning point. It is the ordinate of the new turning point. It is the x-coordinate of the current ship position. It is the vertical coordinate of the current ship position.

[0079] This invention proposes a ship zigzag navigation guidance and control method based on line-of-sight (LOS) guidance. This method organically combines the zigzag navigation method with LOS guidance, designing a zigzag navigation guidance strategy to improve ship navigation safety in adverse sea conditions. Secondly, addressing the large inertia and time delay characteristics in ship track tracking, a tracking control strategy is designed, utilizing the new route distance to adjust waypoints. This is used to enable the ship to quickly return to the planned route when recovering from adverse sea conditions, solving the problem that the zigzag navigation method based on heading-keeping control cannot automatically return to the planned route in normal sea conditions. Finally, a ship control algorithm combining nonlinear feedback and nonlinear embedding methods is proposed, aiming to solve the problems of excessive ship energy output and accelerated rudder wear in adverse sea conditions. Experimental results show that compared with nonlinear feedback and nonlinear embedding controllers, the overall performance of the ship control algorithm designed in this application is improved by 46.4% and 35.6%, respectively. The proposed guidance strategy enables ships to automatically navigate along a "Z" shaped route in adverse sea conditions and automatically return to the planned route when sea conditions return to normal, which has a profound impact on improving the safety, reliability and intelligence of ships. Attached Figure Description

[0080] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0081] Figure 1 This is the final controller structure diagram of this application;

[0082] Figure 2 This is a schematic diagram of the line-of-sight guidance algorithm;

[0083] Figure 3 This is a diagram of a "Z" shaped navigation method;

[0084] Figure 4This is a diagram showing the new course distance.

[0085] Figure 5 It is a flight track chart;

[0086] Figure 6 This is a diagram of the heading control effects;

[0087] Figure 7 This is a diagram of the rudder angle control effect;

[0088] Figure 8 This is a track error diagram. Detailed Implementation

[0089] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0090] A line-of-sight-based zigzag navigation guidance and control method for ships includes the following steps:

[0091] S1. Establish a mathematical model of ship motion;

[0092] S2. Add wind and wave interference factors to the mathematical model of ship motion to obtain the ship motion model under severe sea conditions;

[0093] S3. Based on the ship motion model under severe sea conditions, a preliminary controller is designed using a third-order closed-loop gain shaping algorithm.

[0094] S4. Introduce a nonlinear composite function into the preliminary controller to achieve course-keeping control of the ship. Then, combine nonlinear feedback and nonlinear embedding methods to optimize the preliminary controller and obtain the final controller.

[0095] S5. A "Z" shaped navigation guidance strategy was designed based on the line-of-sight guidance algorithm, enabling the ship to navigate along a "Z" shaped route in adverse sea conditions.

[0096] S6. Adjust waypoints using new course distances to enable vessels to quickly return to their planned routes when returning from severe sea conditions to normal sea conditions.

[0097] The steps S1 / S2 / S3 / S4 / S5 / S6 are executed sequentially;

[0098] The process of designing a preliminary controller based on a ship motion model under severe sea conditions and using a third-order closed-loop gain shaping algorithm is as follows:

[0099] The nonlinear form of the mathematical model for ship motion is:

[0100] (1)

[0101] in: The acceleration of the bow angle is the angular velocity of the bow. The turning angular velocity, As the rudder angle, , All are ship maneuverability indices. A , B It is a nonlinear parameter;

[0102] By linearizing the second-order nonlinear ship model in equation (1), we obtain the transfer function of the second-order linear ship model:

[0103] (2)

[0104] Let the bandwidth frequency of the closed-loop system be... The closed-loop system includes a final controller and a ship motion model; then the complementary sensitivity function of the ship's heading-keeping control system is... That is, the closed-loop transfer function of the closed-loop system is shown in equation (3), where As the controlled object, For the controller:

[0105] (3)

[0106] The initial controller is then given by equation (4):

[0107] (4)

[0108] in: The bandwidth frequency set for the closed-loop system. It is a constant. For the Laplace operator.

[0109] The aforementioned wind and wave interference factors were characterized using the Beaufort scale 6 wind wave interference model and the Beaufort scale 8 wind wave interference model recognized by the International Towing Tank Conference.

[0110] The expression for the wave disturbance model of Beaufort scale 6 wind is as follows:

[0111] (5)

[0112] The expressions for the wave disturbance model of Beaufort scale 8 wind are as follows:

[0113] (6)

[0114] in, It is Gaussian white noise. For the Laplace operator, This is due to high-frequency sea wave interference. The nonlinear composite function... The expression is as follows:

[0115] (7)

[0116] in: These are the coefficients of a nonlinear composite function. It is a variable.

[0117] The nonlinear feedback and nonlinear embedding expressions in the final controller are as follows:

[0118] Nonlinear feedback :

[0119] (8)

[0120] Nonlinear embedding :

[0121] (9)

[0122] in: , For ship maneuverability index, It is a constant;

[0123] By organically integrating nonlinear feedback and nonlinear embedding methods, the final controller is obtained. When the input is small, the amplitude of the output signal is limited by the nonlinear term, which can avoid the system overreaction and thus avoid system overshoot or oscillation. When the input is large, the gain is adjusted by the nonlinear term, making the strength of the control signal more flexible. It is suitable for applications that require fast response and precise gain adjustment.

[0124] Figure 1 This is the final controller structure diagram of this application;

[0125] Figure 2 This is a schematic diagram of the line-of-sight guidance algorithm;

[0126] The line-of-sight (LOS) guidance algorithm is based on the line-of-sight angle between the target and the ship. It uses sensors to measure the deviation between the ship's current position, heading, and preset path in real time, and then generates corresponding control commands to guide the ship to sail along the predetermined route. The specific process is as follows:

[0127] Let the current position coordinates of the ship in the geodetic coordinate system be... , , , ……, The planned tracking points are the first waypoint, the second waypoint, and so on. One waypoint, , The route segment currently planned for tracking requires two steps to achieve tracking control:

[0128] First, determine the trajectory error. This updates the target's position: the target is located at a constant Δ distance from the vertical foot, determined by the ship's performance, based on the target point's coordinates. The ship's expected course is updated in real time. Looking for new The process continued until the ship reached The heading angle of the tracked route segment in the geodetic coordinate system is expressed as: :

[0129] (10)

[0130] in: The ordinate of the second waypoint. The ordinate of the first waypoint. The x-coordinate of the second waypoint The x-coordinate of the second waypoint;

[0131] In path tracking, longitudinal error and lateral error represent the degree to which the current point deviates from the reference path, as follows:

[0132] (11)

[0133] in: The ship's current position. To track the closest point on the flight path; The x-coordinate represents the distance of the current ship's position from the starting point. The vertical coordinate represents the distance of the current ship's position from the starting point;

[0134] Rotation matrix Used to convert from a geodetic coordinate system to a path coordinate system for easier representation of errors, as follows:

[0135] (12)

[0136] Substituting the rotation matrix into the error formula (11), we get:

[0137] (13)

[0138] When expanded, it appears as follows:

[0139] (14)

[0140] (15)

[0141] The ship is expected to converge to the viewpoint quickly and stably. And continue to track along the path, with the expected bow of the ship pointing towards for:

[0142] (16)

[0143] The process of designing a "Z" shaped navigation guidance strategy based on LOS to enable ships to quickly return to their planned course is as follows:

[0144] Figure 3 This is a diagram of a "Z" shaped navigation method;

[0145] The "Z" shaped navigation method involves the ship navigating in a "Z" pattern along a planned route, alternately changing the angle of the bow to reduce the impact of crosswinds and waves, thereby ensuring the ship's safety. The ship navigates with a wave angle of 10° to 30° on one side of the bow for a certain distance, then changes to a wave angle of 10° to 30° on the other side. The route of the "Z" shaped navigation method consists of a series of intersections and vertices.

[0146] Figure 4 This is a diagram showing the distance to the new course;

[0147] The process of adjusting waypoints using new course distances to enable vessels to quickly return to their planned routes when returning from adverse sea conditions to normal sea conditions is as follows:

[0148] The intersection of the "Z" shaped route and the planned route is marked as follows: The intersection points are the first intersection point, the second intersection point, the third intersection point, and so on. One intersection point;

[0149] The apex of the "Z" shaped flight path is the turning point where the course changes angle, marked as... These are respectively the first turning point, the second turning point, the third turning point... Turning point;

[0150] Assumption If the coordinates are the current intersection point, then the next intersection point... The calculation formula is:

[0151] (17)

[0152] (18)

[0153] in: Yaw distance, or the lateral deviation distance in a "Z" shape, is set based on the intensity of wind and waves and the ship's performance. It is the bow of the ship that is affected by the waves. The heading angle of the planned route; It is the x-coordinate of the next intersection point. It is the ordinate of the next intersection point; It is the x-coordinate of the current intersection point. The ordinate of the current intersection point;

[0154] when When the vertex coordinates are odd, The calculation formula is:

[0155] (19)

[0156] (20)

[0157] in: It is the x-coordinate of the vertex. It is the ordinate of the vertex;

[0158] when When the number is even, the vertex coordinates The calculation formula is:

[0159] (twenty one)

[0160] (twenty two)

[0161] If the wind and waves decrease and return to normal sea conditions, when the ship passes the apex... Next intersection point Then, continue sailing along the "Z" shaped route until the ship reaches the next intersection. Directly switch to the planned route.

[0162] Move the current ship position forward by the "new course distance" as the turning point, and set the next intersection point as the turning point. Set as the return route point;

[0163] New course distance The method for obtaining it is as follows:

[0164] (twenty three)

[0165] in: It is the cyclicity index; It is a follower index; It is the initial velocity of the rotation; It is the rudder angle; It is the reversal angle; When steering, the rudder angle changes from normal to... Time required;

[0166] Assumption These are the coordinates of the current ship position. If it is the current heading, then the new turning point The calculation formula is as follows:

[0167] (twenty four)

[0168] (25)

[0169] in: It is the x-coordinate of the new turning point. It is the ordinate of the new turning point. It is the x-coordinate of the current ship position. It is the vertical coordinate of the current ship position.

[0170] Example

[0171] To verify the effectiveness of the method of the present invention, the following simulation experiment was conducted. The ship parameters used in this embodiment are as follows:

[0172] Table 1 Main parameters of "Yupeng Wheel"

[0173]

[0174] Simulation results are as follows Figure 5-8 As shown.

[0175] Figure 5 For flight path chart;

[0176] Figure 6 Diagram of heading control effects;

[0177] Figure 7 Diagram showing the rudder angle control effect;

[0178] Figure 8 This is a trajectory error diagram.

[0179] The planned course was set at 090°, wave direction at 270°, and wave angle at 30°. A zigzag course was used, and the simulation time was 1600 seconds. At the start of the experiment, the wind force was Beaufort scale 8. After 1000 seconds, the wind force decreased to Beaufort scale 6. At this point, the zigzag course was stopped, and the ship began to find the planned route and resume normal navigation.

[0180] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A ship zigzag navigation guidance and control method based on line-of-sight guidance, characterized in that: Includes the following steps: S1. Establish a mathematical model of ship motion; S2. Add wind and wave interference factors to the mathematical model of ship motion to obtain the ship motion model under severe sea conditions; S3. Based on the ship motion model under severe sea conditions, a preliminary controller is designed using a third-order closed-loop gain shaping algorithm. S4. Introduce a nonlinear composite function into the preliminary controller to achieve course-keeping control of the ship. Then, combine nonlinear feedback and nonlinear embedding methods to optimize the preliminary controller and obtain the final controller. S5. A "Z" shaped navigation guidance strategy was designed based on the line-of-sight guidance algorithm, enabling the ship to navigate along a "Z" shaped route in adverse sea conditions. S6. Adjust waypoints using new course distances to enable vessels to quickly return to their planned routes when returning from severe sea conditions to normal sea conditions. The wind and wave interference factors are characterized by the Beaufort scale 6 wind wave interference model and the Beaufort scale 8 wind wave interference model. The expression for the wave disturbance model of Beaufort scale 6 wind is as follows: (5) The expressions for the wave disturbance model of Beaufort scale 8 wind are as follows: (6) in, It is Gaussian white noise. For the Laplace operator, High-frequency sea wave interference; The line-of-sight guidance algorithm is based on the line-of-sight angle between the target and the ship. It uses sensors to measure the deviation between the ship's current position, heading, and preset path in real time, and then generates corresponding control commands to guide the ship to sail along the predetermined route. The specific process is as follows: Let the current position coordinates of the ship in the geodetic coordinate system be... , , , ……, The planned tracking points are the first waypoint, the second waypoint, and so on. One waypoint, , The route segment currently planned for tracking requires two steps to achieve tracking control: First, determine the trajectory error. This updates the position of the tracked target: the target position is a constant determined by the ship's performance at a distance from the vertical foot. Location, based on the coordinates of the target point The ship's expected course is updated in real time. Looking for new The process continued until the ship reached The heading angle of the tracked route segment in the geodetic coordinate system is expressed as: : (10) in: The ordinate of the second waypoint. The ordinate of the first waypoint. The x-coordinate of the second waypoint The x-coordinate of the second waypoint; In path tracking, longitudinal error and lateral error represent the degree to which the current point deviates from the reference path, as follows: (11) in: The ship's current position. To track the closest point on the flight path; The x-coordinate represents the distance of the current ship's position from the starting point. The vertical coordinate represents the distance of the current ship's position from the starting point; Rotation matrix Used to convert from a geodetic coordinate system to a path coordinate system for easier representation of errors, as follows: (12) Substituting the rotation matrix into the error formula (11), we get: (13) When expanded, it appears as follows: (14) (15) The ship is expected to converge to the viewpoint quickly and stably. And continue to track along the path, with the expected bow of the ship pointing towards for: (16)； The process of adjusting waypoints using new course distances to enable vessels to quickly return to their planned routes when returning from adverse sea conditions to normal sea conditions is as follows: The intersection of the "Z" shaped route and the planned route is marked as follows: The intersection points are the first intersection point, the second intersection point, the third intersection point, and so on. One intersection point; The apex of the "Z" shaped flight path is the turning point where the course changes angle, marked as... These are respectively the first turning point, the second turning point, the third turning point... Turning point; Assumption If the coordinates are the current intersection point, then the next intersection point... The calculation formula is: (17) (18) in: Yaw distance, or the lateral deviation distance in a "Z" shape, is set based on the intensity of wind and waves and the ship's performance. It is the bow of the ship that is affected by the waves. The heading angle of the planned route; It is the x-coordinate of the next intersection point. It is the ordinate of the next intersection point; It is the x-coordinate of the current intersection point. The ordinate of the current intersection point; when When the vertex coordinates are odd, The calculation formula is: (19) (20) in: It is the x-coordinate of the vertex. It is the ordinate of the vertex; when When the number is even, the vertex coordinates The calculation formula is: (21) (22) If the wind and waves decrease and return to normal sea conditions, when the ship passes the apex... Next intersection point Then, continue sailing along the "Z" shaped route until the ship reaches the next intersection. Directly switch to the planned route. Move the current ship position forward by "new course distance" as the turning point, and set the next intersection point as... Set as the return route point; New course distance The method for obtaining it is as follows: (23) in: It is the cyclicity index; It is a follower index; It is the initial velocity of the rotation; It is the rudder angle; It is the reversal angle; When steering, the rudder angle changes from normal to... Time required; Assumption These are the coordinates of the current ship position. If it is the current heading, then the new turning point The calculation formula is as follows: (24) (25) in: It is the x-coordinate of the new turning point. It is the ordinate of the new turning point. It is the x-coordinate of the current ship position. It is the vertical coordinate of the current ship position.

2. The method for guidance and control of a ship's zigzag navigation based on line-of-sight guidance according to claim 1, characterized in that: The process of designing a preliminary controller based on a ship motion model under severe sea conditions and using a third-order closed-loop gain shaping algorithm is as follows: The nonlinear form of the mathematical model for ship motion is: (1) in: The acceleration of the bow angle is the angular velocity of the bow. The turning angular velocity, As the rudder angle, , All are ship maneuverability indices. A , B It is a nonlinear parameter; By linearizing the second-order nonlinear ship model in equation (1), we obtain the transfer function of the second-order linear ship model: (2) Let the bandwidth frequency of the closed-loop system be... The closed-loop system includes a final controller and a ship motion model; then the complementary sensitivity function of the ship's heading-keeping control system is... That is, the closed-loop transfer function of the closed-loop system is shown in equation (3), where As the controlled object, For the controller: (3) The initial controller is then given by equation (4): (4) in: The bandwidth frequency set for the closed-loop system. It is a constant. For the Laplace operator.

3. The method for guidance and control of a ship's zigzag navigation based on line-of-sight guidance according to claim 1, characterized in that: The nonlinear composite function The expression is as follows: (7) in: These are the coefficients of a nonlinear composite function. It is a variable.

4. The method for guidance and control of a ship's zigzag navigation based on line-of-sight guidance according to claim 1, characterized in that: The nonlinear feedback and nonlinear embedding expressions in the final controller are as follows: Nonlinear feedback : (8) Nonlinear embedding : (9) in: , For ship maneuverability index, It is a constant; By organically integrating nonlinear feedback and nonlinear embedding, the final controller is obtained.

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