Unmanned ship tracking control method and system based on line-of-sight guidance and series correction

Abstract

The invention relates to an unmanned ship tracking control system and method based on line-of-sight navigation and series correction, electronic equipment and a storage medium. A line-of-sight guidance (LOS) algorithm and a series correction comprehensive method are combined. The LOS algorithm simulates a person to control the ship, and an LOS point is determined to obtain an expected course angle; a hull steering model is corrected into an optimal second-order system through a series correction comprehensive method, a continuous domain controller expression is constructed firstly, and then a discrete domain expression and a correction steering model are obtained through bilinear transformation discretization. The problems that in a complex water area environment, the unmanned ship is difficult to adjust parameters in traditional PID control and poor in control effect due to physical characteristics of the unmanned ship and external strong interference, and the autonomous navigation requirement is difficult to meet are solved. Accurate calculation and control can be carried out based on the target route of the upper computer and real-time information of the unmanned ship in a complex water area, the tracking control precision and stability are improved, and the unmanned ship can effectively track the route in a complex environment.

Description

Technical Field

[0001] The present application relates to the field of unmanned vessel control, and in particular to an unmanned vessel tracking method, system, computer device, and computer-readable storage medium based on line-of-sight navigation and serial correction. Background Art

[0002] Unmanned surface vessels (USVs) are unmanned watercraft with autonomous navigation capabilities. Leveraging advanced sensing, communication, and control systems, they can be used to perform dangerous missions that are difficult for manned vessels. They have broad application prospects in military and civilian fields, such as reconnaissance and patrol, material transportation, maritime rescue, and environmental monitoring.

[0003] Tracking is the foundation of autonomous navigation for unmanned vessels. If there's no risk of collision, the vessel will follow predetermined trackpoints or a planned route. The tracking process involves three components: navigation, observation, and a controller. Navigation sets the desired control target value, observation defines the target state, and the controller generates the control command output. For unmanned vessel navigation, line-of-sight (LOS) algorithms integrate multiple objectives, including safety, efficiency, and reliability, to guide the vessel to track a designated target.

[0004] In related technologies, traditional PID control can meet navigation requirements in calm waters. However, in complex waters, the complex physical characteristics of unmanned vessels, coupled with strong external interference, make traditional PID control algorithms difficult to adjust parameters, resulting in poor control effects and making it difficult to meet the requirements of autonomous navigation. Summary of the Invention

[0005] The embodiments of the present application provide an unmanned vessel tracking control system, method, computer device and computer-readable storage medium based on line-of-sight navigation and serial correction, so as to at least solve the problem of poor control effect of unmanned vessel tracking control algorithm in related technologies.

[0006] In a first aspect, an embodiment of the present application provides an unmanned vessel tracking control system based on line-of-sight navigation and serial correction, the system comprising: an information receiving module, a data processing module, and a heading controller, wherein:

[0007] The information receiving module is used to obtain the real-time position and real-time heading angle of the unmanned ship;

[0008] The data processing module is configured to calculate, based on the real-time position and a preset target route, a desired heading angle corresponding to the real-time position using a line-of-sight navigation algorithm, and obtain a heading deviation between the desired heading angle and the real-time heading angle;

[0009] The heading controller is used to obtain a rudder angle instruction for controlling the tracking of the unmanned ship according to the heading deviation, wherein the heading controller is constructed based on the hull steering model of the unmanned ship through a series correction algorithm.

[0010] In some embodiments, the data processing module includes: an acquisition module, a pre-processing module and a heading angle calculation module, wherein:

[0011] The acquisition module is used to acquire track points from the target route and determine a preset segment between two adjacent track points;

[0012] The preprocessing module is used to determine a line-of-sight navigation point on the preset section according to the vertical distance between the real-time position of the unmanned vessel and the preset section and the line-of-sight range, and to determine a relative movement route between the line-of-sight navigation point and the real-time position;

[0013] The heading angle calculation module is used to calculate the expected heading angle according to the angle between the direction of the relative moving route and a preset reference direction.

[0014] In some embodiments, the data processing module further includes a segment switching module. When the preset target route includes multiple segments, the segment switching module is configured to:

[0015] Determining a first target segment that matches the real-time position based on a preset waypoint number and a current waypoint number, and determining whether to switch the first target segment to an adjacent second target segment based on a preset switching condition while the unmanned vessel is moving in the first target segment;

[0016] If so, a waypoint switching instruction is sent to the pre-processing module to instruct the pre-processing module to calculate the expected heading angle according to the track point corresponding to the second target segment and the real-time position.

[0017] In some embodiments, the flight segment switching module includes an initialization module and a switching control module, wherein:

[0018] The initialization module is used to determine a first target segment matching the real-time position according to a preset waypoint number and a current waypoint number;

[0019] The switching control module is configured to, when the real-time position falls within a preset acceptance circle of track points within the second target segment, output the segment switching instruction to the preprocessing module to instruct it to recalculate the desired heading angle based on the real-time position and the track points of the second target segment.

[0020] In some embodiments, the heading controller includes: a serial correction module and an instruction generation module, wherein:

[0021] The series correction module is used to obtain a steering model of the unmanned ship and construct a continuous domain expression of the heading controller based on the steering model and the optimal second-order system characteristics;

[0022] The continuous domain expression is transformed by using bilinear transformation discretization to obtain a discrete domain expression of the heading controller;

[0023] Based on the discrete domain expression and the relationship between the heading deviation and the rudder angle command in the discrete domain, an expression of the heading controller is obtained;

[0024] The instruction generation module is used to generate a rudder angle instruction for the unmanned ship to track in real time based on the real-time calculated heading deviation through the expression of the heading controller.

[0025] In some embodiments, the discrete domain expression of the heading controller is expressed by the following formula:

[0026]

[0027] Among them, ζ=0.707 is the damping ratio, ω n =1 is the undamped natural oscillation frequency, T1 is the hull time constant, K1 is the hull gain constant, and s is the complex variable in the Laplace transform;

[0028] The continuous domain expression of the heading controller is expressed by the following formula:

[0029]

[0030] Among them, δ(z) represents the rudder angle command at the current moment, Δ(k)Δ(z) represents the heading deviation at the current moment, ζ=0.707 is the damping ratio, ω n =1 is the undamped natural oscillation frequency, T1 is the hull time constant, K1 is the hull gain constant, and z is the complex variable in the z-transform;

[0031] The expression of the heading controller is:

[0032]

[0033] Among them, δ(k) represents the rudder angle command in the discrete domain at the current moment (discrete domain), and δ(k-1) represents the rudder angle command at the previous moment; Δ(k) represents the heading deviation in the discrete domain at the current moment (discrete domain), and Δ(k-1) represents the heading deviation at the previous moment; T is the sampling period, K1 is the hull gain constant, and T1 is the hull time constant.

[0034] In some embodiments, the data receiving module establishes UDP communication with a host computer in a ROS2 environment, and receives the preset target route from the host computer through the UDP communication link;

[0035] The information receiving module, the data processing module and the heading controller communicate with each other through the internal communication mechanism of ROS2 under the ROS2 framework.

[0036] In a second aspect, an embodiment of the present application provides a tracking control method for an unmanned vessel based on line-of-sight navigation and tandem correction, the method comprising:

[0037] The real-time position and heading angle of the unmanned ship are obtained through the information receiving module;

[0038] By using a line-of-sight navigation algorithm, a data processing module calculates a desired heading angle corresponding to the real-time position based on the real-time position and a preset target route, and obtains a heading deviation between the desired heading angle and the real-time heading angle;

[0039] A rudder angle instruction for controlling the tracking of the unmanned ship is obtained through a heading controller according to the heading deviation, wherein the heading controller is constructed based on a hull steering model of the unmanned ship through a series correction algorithm.

[0040] In a third aspect, an embodiment of the present application provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described in the second aspect above when executing the computer program.

[0041] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the second aspect above.

[0042] Compared with related technologies, the unmanned ship tracking control system based on line-of-sight navigation and serial correction provided by the embodiment of the present application combines the line-of-sight guidance (LOS) algorithm with the serial correction synthesis method; the LOS algorithm simulates human control of the ship to determine the LOS point to obtain the desired heading angle; the serial correction synthesis method corrects the hull steering model to the optimal second-order system, first constructs the continuous domain controller expression, and then uses bilinear transformation to discretize to obtain the discrete domain expression and the corrected steering model. It solves the problem that in complex water environments, unmanned ships are difficult to meet the requirements of autonomous navigation due to their own physical characteristics and strong external interference, resulting in difficult traditional PID control parameter adjustment and poor control effect. In complex waters, it can accurately calculate and control based on the host computer's target route and the unmanned ship's real-time information, thereby improving the tracking control accuracy and stability, allowing the unmanned ship to effectively track the route in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0044] Figure 1 This is a structural block diagram of an unmanned vessel tracking control system based on line-of-sight navigation and tandem correction according to an embodiment of the present application;

[0045] Figure 2 is a schematic diagram of calculating the LOS angle according to an embodiment of the present application;

[0046] Figure 3 is a schematic diagram of flight segment switching according to an embodiment of the present application;

[0047] Figure 4 is a control block diagram of a hull steering model according to an embodiment of the present application;

[0048] Figure 5 is an equivalent block diagram of a heading controller according to an embodiment of the present application;

[0049] Figure 6 This is a flow chart of a tracking control method for an unmanned vessel based on line-of-sight navigation and tandem correction according to an embodiment of the present application;

[0050] Figure 7 This is a flow chart of flight segment determination according to an embodiment of the present application;

[0051] Figure 8 This is a flow chart of data communication between modules according to an embodiment of the present application;

[0052] Figure 9 is another flow chart of an unmanned vessel tracking control method based on line-of-sight navigation and tandem correction according to an embodiment of the present application;

[0053] Figure 10 Schematic diagram of the internal structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of this application.

[0055] Obviously, the drawings described below are merely examples or embodiments of the present application. Those skilled in the art can, without inventive effort, apply the present application to other similar scenarios based on these drawings. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, changes in design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in this application.

[0056] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments unless there is a conflict.

[0057] Unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by a person of ordinary skill in the technical field to which this application belongs. The words "one", "a", "the" and the like used in this application do not indicate a limit on quantity and may indicate the singular or plural. The terms "include", "comprise", "have" and any variations thereof used in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units that are inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The word "multiple" used in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0058] An unmanned surface vessel (USV) is an unmanned surface vessel with autonomous navigation capabilities. Equipped with advanced sensing, communication, and control systems, it can perform dangerous missions that manned vessels cannot. Due to their high safety and efficiency, unmanned vessels have broad applications in both military and civilian fields, such as reconnaissance and patrol, material transportation, maritime rescue, and environmental monitoring.

[0059] Tracking is the foundation of autonomous navigation technology for unmanned vessels. When sailing at sea, an unmanned vessel will follow predetermined track points or a planned route, provided there is no risk of collision. Tracking for unmanned vessels requires simultaneous consideration of three components: navigation, observation, and controller. Navigation determines the desired control target value, observation determines the control target state value, and the controller determines the control command output value. For unmanned vessel navigation, line-of-sight (LOS) algorithms combine multiple objectives, including navigation safety, efficiency, and reliability, to guide the vessel to track a designated target.

[0060] With the widespread popularity of global navigation satellite systems such as GPS and Beidou, and the maturity of differential positioning technology and environmental perception technology, ships equipped with advanced perception systems can now accurately obtain the state values of control targets, effectively improving the accuracy, stability and real-time performance of unmanned ship tracking, making it possible to accurately track the unmanned ships to meet the needs of autonomous navigation.

[0061] The controller design directly impacts the accuracy and stability of the unmanned vessel's tracking function. In relatively calm waters, traditional PID control can meet navigation requirements. However, in complex waters, due to the unmanned vessel's inherently complex physical characteristics and strong external interference, traditional PID control algorithms face difficulties in parameter adjustment and poor control performance, making them difficult to meet the requirements of autonomous navigation. Therefore, it is necessary to design an algorithm that can achieve better tracking and control performance in complex waters. Given the limited availability of relevant research, designing a practical and feasible unmanned vessel tracking control system is crucial.

[0062] In view of this, the embodiment of the present application provides an unmanned vessel tracking control system based on line-of-sight navigation and serial correction. Figure 1 This is a structural block diagram of an unmanned ship tracking control system based on line-of-sight navigation and serial correction according to an embodiment of the present application. Figure 1 As shown, the system includes: an information receiving module 10, a data processing module 20 and a heading controller 30, wherein:

[0063] The information receiving module 10 is used to obtain the real-time position and real-time heading angle of the unmanned ship;

[0064] In this embodiment, the module can obtain the real-time location information of the unmanned vessel through various methods. For example, real-time positioning results can be obtained through an inertial navigation device, or satellite positioning technologies such as the Global Positioning System (GPS) or the Beidou Navigation System can be used to receive satellite signals to determine the latitude and longitude coordinates of the unmanned vessel on the earth, thereby obtaining its precise location. Other positioning methods can also be combined, such as base station positioning (if there is suitable base station coverage near the water area), to improve the accuracy and reliability of the location information.

[0065] Inertial navigation equipment is often used to obtain the real-time heading angle of an unmanned vessel. Furthermore, other auxiliary sensors or algorithms can be combined to improve the accuracy of the heading angle. For example, by fusing data from multiple sensors (such as GPS velocity vector direction and gyroscopic angular velocity integral), a more reliable real-time heading angle can be obtained.

[0066] In this embodiment, the real-time position and real-time heading angle information directly reflect the current position and navigation direction of the unmanned ship, providing a data basis for the subsequent calculation of the expected heading angle and the judgment of whether the unmanned ship has deviated from the route.

[0067] The data processing module 20 is used to calculate the desired heading angle corresponding to the real-time position and obtain the heading deviation between the desired heading angle and the real-time heading angle based on the real-time position and the preset target route using a line-of-sight navigation algorithm;

[0068] Among them, this module receives the desired target route drawn by the upper computer chart software, combines the real-time position of the hull fed back by the unmanned ship, and uses the LOS algorithm to calculate the expected heading angle of the current position relative to the preset track point; the expected heading angle is used to combine with the current heading angle to obtain the heading deviation as the input of the heading controller 30 to provide heading control for the path tracking of the unmanned ship.

[0069] Specifically, in this embodiment, the data processing module 20 includes: an acquisition module 201, a pre-processing module 202 and a heading angle calculation module 203, wherein:

[0070] The acquisition module 201 is used to acquire track points from the target route and determine the preset segment between two adjacent track points;

[0071] It should be noted that the target route is obtained from the host computer chart software. The route is pre-drawn by the developer based on specific expectations and can be updated in real time based on environmental changes. It can include one or more established segments, each segment being determined by two adjacent track points.

[0072] The host computer's chart software interface presents oceanographic information using electronic nautical charts. Operators can optionally specify the starting point, end point, and waypoints of the target route on the chart by clicking and dragging the mouse. The software provides zoom and pan functions to assist in planning, displaying real-time information such as route length, estimated sailing time, and distance to obstacles, ensuring a reasonable and safe route.

[0073] The mapped target route data is stored in a specific format, including waypoint coordinates and route attributes. Once ready, the host computer can encode and package the data and send it to the UAV control system via UDP network communication, ensuring accurate reception and interpretation for tracking control.

[0074] The pre-processing module 202 is used to determine a line-of-sight navigation point on the preset section according to the real-time position of the unmanned vessel, the distance from the preset section, and the line-of-sight range, and to determine a relative movement route between the line-of-sight navigation point and the real-time position;

[0075] The heading angle calculation module 203 is used to calculate the expected heading angle according to the angle between the direction of the relative moving route and a preset reference direction.

[0076] Specifically, with reference to a specific example, Figure 2 Schematic diagram of calculating the LOS angle according to an embodiment of the present application, as shown in FIG. Figure 2 As shown:

[0077] The route planning preset in the chart software is a line segment from point P1 = (x1, y1) to point P2 = (x2, y2). A point P0 = (x0, y0) outside the track represents the current position of the unmanned vessel, and the speed is v; the sight radius R0 = (3 to 5) times the ship length, and a circle is drawn with R0 as the radius to the next target track point. The intersection point is the LOS point P LOS =(x LOS ,y LOS ), d represents the distance from the current position to the route, and the perpendicular coordinate point is P N =(x N ,y N ).

[0078] In addition, if Figure 2 As shown, the vertical line d is used to determine the LOS point position in conjunction with the real-time position. Based on the vertical line d, the shortest distance from the UAV's current position to the target route can be found. Furthermore, combined with the line of sight radius, the unique LOS point can be determined, thereby accurately calculating the desired heading angle. As can be seen, without the vertical line, the unique LOS point cannot be determined, affecting the calculation of the desired heading angle and, in turn, the accuracy of tracking control.

[0079] Further, if Figure 2As shown, while the hull velocity v does not directly contribute to the calculation of the desired heading angle, it indirectly affects the unmanned vessel's dynamic response characteristics. At high speeds, steering inertia is greater, requiring a larger rudder angle and adjustment time; the opposite is true at low speeds. Velocity information subsequently helps the control system adjust the rudder angle command to accommodate navigation at varying speeds. Velocity is also used to calculate the unmanned vessel's predicted future position, assisting in planning control strategies, avoiding collisions, and optimizing navigation paths.

[0080] In addition, it should be noted that the data processing module 20 further includes a flight segment switching module 204. When the preset target route includes multiple flight segments, the flight segment switching module 204 includes an initialization module 2041 and a switching control module 2042:

[0081] The initialization module 2041 is used to determine a first target segment that matches the real-time position based on a preset waypoint number and a current waypoint number. The switching control module 2042 is used to determine whether to switch the first target segment to an adjacent second target segment based on a preset switching condition while the unmanned vessel is moving in the first target segment.

[0082] If so, a waypoint switching instruction is sent to the pre-processing module 202 to instruct the pre-processing module 202 to calculate the expected heading angle according to the track point corresponding to the second target segment and the real-time position.

[0083] Specifically, with reference to a specific example, Figure 3 Schematic diagram of flight segment switching according to an embodiment of the present application, such as Figure 3 As shown:

[0084] When the preset target route consists of multiple target segments, it is necessary to design a switching segment. The current waypoint number and the target waypoint number are set to determine which target segment the current segment is in. The starting waypoint is point 1, and the subsequent waypoint numbers are incremented by 1. During the navigation process, a switching condition is required to determine whether to switch to the next waypoint. The switching condition is shown in the following formula:

[0085]

[0086] When the unmanned ship enters the following waypoint [x d (k), y d (k)] is the center of the circle and R1 is the radius of the acceptance circle, it is determined to have arrived at the target waypoint and entered the segment starting from the waypoint. The target waypoint is switched to the next waypoint [x d (k+1), y d (k+1)], the current waypoint number is increased by 1. At this time, the target segment changes, and the desired heading angle also changes accordingly, until the last target waypoint is tracked.

[0087] During the design process of this system, the human driving control logic was combined. When controlling a ship, people usually look ahead at a certain distance. The intersection of this line of sight radius and the target route is the LOS point to be tracked. The angle between the current ship's position and the LOS point is the LOS angle.

[0088] This system uses a Loss of Sight (LOS) algorithm to simulate human control logic for tracking a vessel. The preprocessing module 202 and the heading angle calculation module 203 work in conjunction with each other, using the LOS algorithm to calculate the Loss of Sight (LOS) angle in real time. This LOS angle constrains the unmanned vessel's direction of travel. Traditional control variables (heading angle and unmanned vessel position) can be simplified to heading angle and navigation speed. The desired LOS angle is calculated based on the unmanned vessel's motion state and target route information.

[0089] The heading controller 30 is used to obtain a rudder angle instruction for controlling the tracking of the unmanned ship according to the heading deviation, wherein the heading controller 30 is constructed based on the hull steering model of the unmanned ship through a series correction algorithm.

[0090] Finally, the required control rudder angle is calculated by the heading controller 30, thereby achieving the effect of reducing both position deviation and heading deviation. It can be understood that if the LOS calculation is correct and the hull control is accurate, the unmanned ship will gradually converge to the target route and achieve the effect of path tracking.

[0091] In addition, it should be noted that considering that unmanned ships face various interferences and their own complex physical characteristics when sailing in complex waters, the traditional PID control algorithm has the problem of poor control effect;

[0092] In this system, the controller design uses a series correction synthesis method, employing a linear system correction synthesis method to correct the controlled object (the ship's steering model) into an optimal second-order system to optimize system performance. The goal is to enable the unmanned vessel to better track the desired heading angle in complex waters, overcoming the difficulties of traditional PID control in adjusting parameters and achieving poor control performance in such complex environments, thereby achieving precise tracking control.

[0093] In this embodiment, the controlled object (the hull steering model, including the first-order inertial component and the integral component) is calibrated to an optimal second-order system. Because the optimal second-order system has excellent dynamic and steady-state performance, such as small overshoot and short settling time, it enables the unmanned vessel to more accurately track the desired heading angle, navigating along the target route and improving tracking accuracy.

[0094] Furthermore, calculating the appropriate control signal (rudder angle command) based on the system characteristics can also ensure that the unmanned ship obtains the best control effect under different navigation conditions, solve the shortcomings of traditional PID control in complex water environments, and meet the requirements of autonomous navigation.

[0095] Specifically, in this system, the heading controller 30 includes a series correction module 301 and an instruction generation module 302, wherein:

[0096] The series correction module 301 is used to obtain the steering model of the unmanned ship and construct a continuous domain expression of the heading controller 30 that conforms to the optimal second-order system based on the steering model and the optimal second-order system characteristics;

[0097] In this embodiment, the ship's steering model consists of a first-order inertia link and an integral link. The first-order inertia link reflects the ship's inertial response to the steering command, that is, due to factors such as the hull's mass and water resistance, the ship will not change its course immediately after receiving the steering command, but there will be a certain delay, and its time constant reflects the magnitude of this inertia. Furthermore, the integral link accumulates the changes in the steering angle, which is used to more accurately describe the ship's steering state. Continuous small-angle steering can be accumulated to comprehensively consider the overall steering situation. In addition, the ship's gain constant represents the proportional relationship between the input rudder angle command and the output heading angle change. It can be identified through steering experiments and provides basic parameters for subsequent controller design.

[0098] Figure 4 This is a control block diagram of a hull steering model according to an embodiment of the present application.

[0099] In the process of designing the heading controller 30, the controlled object is calibrated according to the optimal second-order system. Specifically, in order to make the control system as a whole equivalent to the optimal second-order system, Figure 5 is an equivalent block diagram of a heading controller according to an embodiment of the present application, such as Figure 5 As shown, the controller C(s) is given as follows:

[0100]

[0101] Among them, ζ=0.707 is the damping ratio, ω n =1 is the undamped natural oscillation frequency, T1 is the hull time constant, K1 is the hull gain constant, and s is the complex variable in the Laplace transform; those skilled in the art will understand that this expression is constructed by combining the optimal second-order system characteristics and the above-mentioned hull steering model.

[0102] Furthermore, the series correction module 302 uses bilinear transformation discretization to transform the continuous domain expression to obtain the discrete domain expression of the heading controller;

[0103] Specifically, the bilinear transformation discretization method is used.

[0104]

[0105] Among them, T = 0.1s is the sampling period, which can be substituted into the controller to obtain:

[0106]

[0107] Among them, δ(z) represents the rudder angle command at the current moment, Δ(z) represents the heading deviation at the current moment, ζ=0.707 is the damping ratio, ω n =1 is the undamped natural oscillation frequency, T1 is the hull time constant, K1 is the hull gain constant, and z is the complex variable in the z-transform.

[0108] It's important to note that in an unmanned vessel tracking control system, the final control signal must be transmitted through a digital device (such as a computer or microcontroller) to control the vessel. These digital devices can only process discrete digital signals, while the controller expression for direct correction is in the continuous domain and cannot be directly applied to digital control systems. Therefore, a bilinear transformation discretization method is required to convert the continuous-domain controller model into the discrete domain.

[0109] Specifically, the bilinear transformation employed in this implementation approximates the characteristics of continuous systems. Through specific mathematical transformations, the frequency characteristics in the continuous domain are mapped to the discrete domain, making the discretized system's performance as close as possible to that of the original continuous system. This ensures that excessive errors are not introduced during the discretization process, thereby maintaining the stability and accuracy of the unmanned vessel's tracking control system.

[0110] After bilinear transformation, since δ(z)=δ(k), δ(z)z -1 =δ(k-1), Δ(z)=Δ(k), Δ(z)z -1 =Δ(k-1), the expression of the heading controller can be obtained as:

[0111]

[0112] Among them, δ(k) represents the rudder angle command at the current moment (discrete domain), δ(k-1) represents the rudder angle command at the previous moment; Δ(k) represents the heading deviation at the current moment (discrete domain), Δ(k-1) represents the heading deviation at the previous moment; T is the sampling period, ζ is the damping ratio, ω n is the undamped natural oscillation frequency, K1 is the hull gain constant, and T1 is the hull time constant.

[0113] Those skilled in the art will understand that the specific derivation of the above formula, within the technical framework of the heading controller constructed using the cascade correction algorithm in this embodiment, is a common method used in discrete control system analysis. Through a series of mathematical transformations and approximations, an expression for a heading controller applicable in practical digital control systems can be derived. This expression is used to calculate the rudder angle command based on the heading deviation, thereby achieving heading control for the unmanned vessel.

[0114] The instruction generation module 302 is used to generate a rudder angle instruction for the unmanned ship to track in real time based on the real-time calculated heading deviation through the expression of the heading controller.

[0115] This module uses the controller expression obtained in the above steps to generate the rudder angle command. During the tracking process, it receives real-time heading deviation information from other parts of the system (such as the inertial navigation module) and inputs it into the expression of the heading controller 30. Based on the specific calculation logic in the heading controller 30, it combines the current and previous heading deviations and the previous rudder angle command to calculate the current rudder angle command.

[0116] The rudder angle command is sent to the UAV's steering gear actuator, controlling the steering gear's rotation angle, thereby adjusting the UAV's heading, steering it toward the desired course and achieving tracking control. During navigation, the command generation module 302 continuously repeats this process, generating appropriate rudder angle commands based on the course deviation in real time, ensuring the UAV accurately tracks the target route and adapts to complex water environments.

[0117] The above system, compared with the unmanned ship tracking algorithm in related technologies, combines the line-of-sight guidance (LOS) algorithm with the serial correction synthesis method; the LOS algorithm simulates human control of the ship, determines the LOS point based on the unmanned ship's position, target route and line of sight radius to obtain the desired heading angle; the serial correction synthesis method corrects the hull steering model to the optimal second-order system, first constructing the continuous domain controller expression, and then using bilinear transformation to discretize to obtain the discrete domain expression and the corrected steering model. This solves the problem that unmanned ships in complex water environments are difficult to meet the requirements of autonomous navigation due to their own physical characteristics and strong external interference, resulting in difficult traditional PID control parameter adjustment and poor control effect. It improves tracking accuracy, stability and real-time performance, allowing unmanned ships to effectively track routes in complex environments.

[0118] On the other hand, the embodiment of the present application also provides an unmanned vessel tracking control method based on line-of-sight navigation and tandem correction. Figure 6 FIG. 1 is a flow chart of an unmanned vessel tracking control method based on line-of-sight navigation and serial correction according to an embodiment of the present application. Figure 6 As shown, the method includes the following steps:

[0119] S601, obtaining the real-time position and real-time heading angle of the unmanned vessel through the information receiving module;

[0120] The module can obtain the real-time location information of the unmanned vessel in a variety of ways. For example, it can use satellite positioning technologies such as inertial navigation devices, the Global Positioning System (GPS), or the Beidou Navigation System to receive satellite signals to determine the latitude and longitude coordinates of the unmanned vessel on the earth, thereby obtaining its precise position.

[0121] S602, using a line-of-sight navigation algorithm through a data processing module, based on the real-time position and a preset target route, calculates a desired heading angle corresponding to the real-time position, and obtains a heading deviation between the desired heading angle and the real-time heading angle;

[0122] The module uses the upper computer chart software to draw the desired target route, combines the real-time position of the hull fed back by the unmanned vessel, and uses the LOS algorithm to calculate the desired heading angle of the current position relative to the preset navigation system; the desired heading angle is used to combine with the current heading angle to obtain the heading deviation, which serves as the input of the heading controller to provide heading control for the path tracking of the unmanned vessel.

[0123] in addition, Figure 7 This is a flow chart of flight segment judgment according to an embodiment of the present application, such as Figure 7 As shown, when the preset target route includes multiple segments, the segment switching module determines whether the unmanned vessel has reached the target waypoint. The target waypoint is considered reached when the unmanned vessel is within a certain range of the target waypoint or has already exceeded the target waypoint. The distance within this range is defined as the acceptance radius. If the next target waypoint is reached, the waypoint number is incremented by 1, the target route is switched to the next segment, and the linear equation is recalculated. If the waypoint is not reached, the distance between the current unmanned vessel position and the target waypoint is calculated based on the linear equation of the current target route until the voyage ends.

[0124] S603, obtaining a rudder angle instruction for controlling the tracking of the unmanned ship according to the heading deviation through a heading controller, wherein the heading controller is constructed based on the hull steering model of the unmanned ship through a series correction algorithm.

[0125] The ship steering model was calibrated to an optimal second-order system. This optimal second-order system exhibits excellent dynamic and steady-state performance, such as minimal overshoot and short settling time. This allows the unmanned vessel to more accurately track the desired heading angle, following the target route, and improving tracking accuracy. Furthermore, the appropriate control signal (rudder angle command) is calculated based on the system's characteristics to ensure optimal control under various navigation conditions. This effectively overcomes the shortcomings of traditional PID control in complex waters and meets the requirements for autonomous navigation.

[0126] In addition, each module in this method relies on the ROS2 environment under the Ubuntu operating system for development, and the hardware platform used is Advantech IPC-610-L.

[0127] Figure 8 This is a flow chart of data communication between modules according to an embodiment of the present application. Figure 8 As shown in the figure, under the framework of ROS2, the reliability of data interaction within the system is guaranteed. At the same time, the modular design makes the subsequent expansion of the system (such as adding obstacle avoidance functions, etc.) more convenient. The overall system can be divided into four modules: target route receiving module, inertial navigation information receiving module, LOS algorithm module, and heading controller module. The system completes data interaction between devices through UDP network communication and completes data communication between processes in the ROS2 environment. First, the target route receiving module establishes UDP communication with the host computer in the ROS2 environment, monitors the port of the host computer sending the target route in real time, stores the received target route information at a frequency of 100Hz and publishes it to the topic for calculation by the LOS algorithm module.

[0128] Next, the inertial navigation module sends 10 messages per second via UDP communication, and the inertial navigation information receiving module also receives and publishes topics at a frequency of 100 Hz. Furthermore, the Loss of Sight (LOS) algorithm module subscribes to the topics published by the first two modules, obtains the data required for analysis, and transmits the calculated desired Loss of Sight angle to the heading controller.

[0129] Finally, the heading controller module obtains the heading deviation based on the acquired LOS angle and the current heading angle of the hull, calculates the required rudder angle command, and sends it to the USV through UDP communication at a frequency of 1 Hz.

[0130] also, Figure 9 is another flow chart of the unmanned vessel tracking control method based on line-of-sight navigation and serial correction according to an embodiment of the present application, such as Figure 9 As shown in the figure, the unmanned vessel is guided based on the LOS algorithm, and a controller is designed according to the hull steering model to provide heading control for the unmanned vessel's path tracking. The desired target route is plotted using the host computer's nautical chart software. Combined with the current latitude and longitude information of the hull fed back by the USV, the LOS algorithm is used to calculate the desired heading angle for the current position. The heading deviation is then derived based on the hull's current heading angle and serves as the input for the heading controller. Finally, the series-corrected heading controller generates a rudder angle command and sends it to the USV, completing the overall closed-loop control system. The proposed unmanned vessel tracking control system can still provide good control and tracking effects even in complex water environments.

[0131] Through steps S601 to S603, the LOS algorithm simulates human control of the ship. The LOS point is determined based on the unmanned ship's position, target route, and line of sight radius to obtain the desired heading angle. The cascade correction synthesis method corrects the hull steering model to an optimal second-order system, first constructing a continuous domain controller expression, then using bilinear transformation to discretize it to obtain a discrete domain expression and a corrected steering model. This solves the problem of unmanned ships in complex waters, where the physical characteristics of the unmanned ship and strong external interference prevent traditional tracking algorithms from meeting the requirements of autonomous navigation. This improves tracking accuracy, stability, and real-time performance, allowing unmanned ships to effectively track routes in complex environments.

[0132] In one embodiment, Figure 10 is a schematic diagram of the internal structure of an electronic device according to an embodiment of the present application, such as Figure 10 As shown, an electronic device is provided, which may be a server, and its internal structure diagram may be as shown in FIG. Figure 10 As shown. This electronic device includes a processor, a network interface, an internal memory, and a non-volatile memory connected via an internal bus, wherein the non-volatile memory stores an operating system, a computer program, and a database. The processor is used to provide computing and control capabilities, the network interface is used to communicate with external terminals via a network connection, the internal memory is used to provide an environment for the operation of the operating system and computer program. When the computer program is executed by the processor, it implements an unmanned vessel tracking control method based on line-of-sight navigation and tandem correction. The database is used to store data.

[0133] Those skilled in the art will understand that Figure 10 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the electronic device to which the solution of the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0134] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, which can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0135] The above embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An unmanned vessel tracking control system based on line-of-sight navigation and serial correction, characterized in that: The system includes: an information receiving module, a data processing module and a heading controller, wherein: The information receiving module is used to obtain the real-time position and real-time heading angle of the unmanned ship; The data processing module is configured to calculate, based on the real-time position and a preset target route, a desired heading angle corresponding to the real-time position using a line-of-sight navigation algorithm, and obtain a heading deviation between the desired heading angle and the real-time heading angle; The heading controller is used to obtain a rudder angle instruction for controlling the tracking of the unmanned ship according to the heading deviation, wherein the heading controller is constructed based on the hull steering model of the unmanned ship through a series correction algorithm.

2. The system according to claim 1, wherein: The data processing module includes: an acquisition module, a pre-processing module and a heading angle calculation module, wherein: The acquisition module is used to acquire track points from the target route and determine a preset segment between two adjacent track points; The preprocessing module is used to determine a line-of-sight navigation point on the preset section according to the vertical distance between the real-time position of the unmanned vessel and the preset section and the line-of-sight range, and to determine a relative movement route between the line-of-sight navigation point and the real-time position; The heading angle calculation module is used to calculate the expected heading angle according to the angle between the direction of the relative moving route and a preset reference direction.

3. The system according to claim 2, characterized in that The data processing module further includes a segment switching module. When the preset target route includes multiple segments, the segment switching module is used to: Determining a first target segment that matches the real-time position based on a preset waypoint number and a current waypoint number, and determining whether to switch the first target segment to an adjacent second target segment based on a preset switching condition while the unmanned vessel is moving in the first target segment; If so, a waypoint switching instruction is sent to the pre-processing module to instruct the pre-processing module to calculate the expected heading angle according to the track point corresponding to the second target segment and the real-time position.

4. The system according to claim 3, characterized in that The flight segment switching module includes an initialization module and a switching control module, wherein: The initialization module is used to determine a first target segment matching the real-time position according to a preset waypoint number and a current waypoint number; The switching control module is configured to, when the real-time position falls within a preset acceptance circle of track points within the second target segment, output the segment switching instruction to the preprocessing module to instruct it to recalculate the desired heading angle based on the real-time position and the track points of the second target segment.

5. The system according to claim 1, wherein: The heading controller includes: a series correction module and an instruction generation module, wherein: The series correction module is used to obtain a steering model of the unmanned ship and construct a continuous domain expression of the heading controller based on the steering model and the optimal second-order system characteristics; The continuous domain expression is transformed by using bilinear transformation discretization to obtain a discrete domain expression of the heading controller; Based on the discrete domain expression and the relationship between the heading deviation and the rudder angle command in the discrete domain, an expression of the heading controller is obtained; The instruction generation module is used to generate a rudder angle instruction for the unmanned ship to track in real time based on the heading deviation calculated in real time through the expression of the heading controller.

6. The system according to claim 5, characterized in that The continuous domain expression of the heading controller is expressed by the following formula: Among them, ζ=0.707 is the damping ratio, ω n =1 is the undamped natural oscillation frequency, T1 is the hull time constant, K1 is the hull gain constant, and s is the complex variable in the Laplace transform; The discrete domain expression of the heading controller is expressed by the following formula: Among them, δ(z) represents the rudder angle command at the current moment, Δ(z) represents the heading deviation at the current moment, ζ=0.707 is the damping ratio, ω n =1 is the undamped natural oscillation frequency, T1 is the hull time constant, K1 is the hull gain constant, and z is the complex variable in the z-transform; The expression of the heading controller is: Among them, δ(k) represents the rudder angle command in the discrete domain at the current moment, and δ(k-1) represents the rudder angle command at the previous moment; Δ(k) represents the heading deviation in the discrete domain at the current moment, and Δ(k-1) represents the heading deviation at the previous moment; T is the sampling period, K1 is the hull gain constant, and T1 is the hull time constant.

7. The system according to claim 1, wherein: The data receiving module establishes UDP communication with the host computer in the ROS2 environment, and receives the preset target route from the host computer through the UDP communication link; The information receiving module, the data processing module and the heading controller communicate with each other through the internal communication mechanism of ROS2 under the ROS2 framework.

8. A tracking control method for an unmanned vessel based on line-of-sight navigation and serial correction, characterized in that: The method comprises: The real-time position and heading angle of the unmanned ship are obtained through the information receiving module; By using a line-of-sight navigation algorithm, a data processing module calculates a desired heading angle corresponding to the real-time position based on the real-time position and a preset target route, and obtains a heading deviation between the desired heading angle and the real-time heading angle; A rudder angle instruction for controlling the tracking of the unmanned ship is obtained through a heading controller according to the heading deviation, wherein the heading controller is constructed based on a hull steering model of the unmanned ship through a series correction algorithm.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to claim 8 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to claim 8 is implemented.

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