Cooperative path tracking control method for multiple unmanned ships

Abstract

The invention discloses a multi-unmanned ship cooperative path tracking control method, which comprises the following steps: acquiring an expected path of a leader unmanned ship, and constructing a tangent coordinate system based on the expected path of the leader; calculating a tangential tracking error and a cross tracking error of the follower unmanned ship according to the real-time position information of the follower unmanned ship based on a tangential coordinate system of the expected path of the leader; obtaining expected values of tangential tracking errors and cross tracking errors according to an expected formation; an expected heading angle and an expected resultant velocity are obtained, so that a tangential tracking error and a cross tracking error of the follower unmanned ship are converged to corresponding expected values; and by taking the expected heading angle and the expected resultant velocity as tracking targets, controlling the follower unmanned ship through a thrust controller and a rudder angle controller based on a tracking differentiator. According to the method, the cooperative path tracking precision of the multiple unmanned ships can be improved, and meanwhile, the follower unmanned ships converge to the expected relative position of the leader so as to keep the expected formation.

Description

Technical Field

[0001] The invention relates to the technical field of automatic control of unmanned boats, and in particular to a collaborative path tracking control method for multiple unmanned boats. Background Art

[0002] As a new type of intelligent equipment, unmanned boats have the advantages of small size, high speed, small radar reflection area, etc., and can be flexibly deployed in rivers, lakes and seas. They are designed to perform a variety of tasks such as underwater obstacle removal, patrol, equipment and material transportation, and emergency rescue. The unmanned design of unmanned boats enables them to perform tasks in high-risk environments such as complex hydrological and meteorological conditions and biochemical radiation. Therefore, using unmanned boats to perform tasks can be safer and more efficient.

[0003] Considering that a single unmanned boat is difficult to perform complex tasks such as collective patrol, rescue, capture, monitoring and reconnaissance, multiple unmanned boats have the advantages of high efficiency, good flexibility, strong adaptability to complex environments, large coverage area, and a wide variety of tasks. In actual tasks, a desired path is often planned, and the unmanned boat cluster needs to track the desired path and then reach the target location. Considering the needs of the task and the interference of the complex environment, the unmanned boat cluster needs to form and switch formations to improve the completion rate of the task.

[0004] In the prior art, if the dynamic characteristics of the unmanned boat are not considered, an observer or estimator-based method is used to estimate the path variables and their changing speed of the leader, such as [Zhouhua Peng, Jun Wang and Dan Wang. Distributed Maneuvering of Autonomous Surface Vehicles Based on Neurodynamic Optimization and Fuzzy Approximation. 2018. 26(03):1083-1090]. However, the unmanned boat has the under-actuated dynamic characteristics, which makes this method difficult to apply in practice. After considering the under-actuated characteristics, for the path tracking task of multiple unmanned boats, the traditional line of sight guidance method is generally used to track the path of a single unmanned boat, such as [Nan Gu, ZhouhuaPeng, Dan Wan, Yang Shi and Tianlin Wang. Antidisturbance Coordinated PathFollowing Control of Robotic Autonomous Surface Vehicles: Theory and Experiment [J]. IEEE / ASME Transactions on Mechatronics, 2022, 40(02): 2386-2396], the expected heading angle is designed using the traditional line-of-sight guidance law, but the driving speed cannot be designed. Therefore, this method can only meet the path tracking of unmanned boats with a specific initial position, and the unmanned boats cannot maintain a specific formation. Summary of the invention

[0005] The purpose of the present invention is to provide a method for controlling the coordinated path tracking of multiple unmanned boats, so as to realize the coordinated path tracking control of multiple unmanned boats, improve the coordinated path tracking accuracy of multiple unmanned boats, and make the follower unmanned boats converge to the expected relative position of the leader to maintain the expected formation. The technical solution adopted by the present invention is as follows.

[0006] In one aspect, the present invention provides a method for collaborative path tracking control of multiple unmanned boats, comprising:

[0007] Obtain the expected path information of the leader unmanned boat and construct a tangent coordinate system based on the leader's expected path;

[0008] Obtain the real-time position information of the follower unmanned boat, and calculate the tangential tracking error and cross tracking error of the follower unmanned boat based on the tangent coordinate system of the leader's expected path and the real-time position information of the follower unmanned boat;

[0009] According to the expected formation, the expected values ​​of the tangential tracking error and the cross tracking error of the follower unmanned boat in the tangent coordinate system are obtained;

[0010] Calculating an expected heading angle that can make the cross-tracking error of the follower unmanned boat converge to an expected value of the cross-tracking error, and an expected combined speed that can make the tangential tracking error converge to the expected value of the tangential tracking error;

[0011] The real-time heading angle and real-time resultant speed of the follower unmanned boat are obtained, and the desired heading angle and desired resultant speed are used as tracking targets. The follower unmanned boat is controlled by a thrust controller and a rudder angle controller based on a tracking differentiator.

[0012] Optionally, the desired path of the leader unmanned boat is represented as a path point A collection of, among which, is the path variable; and is the path point coordinate component;

[0013] The construction of the tangent coordinate system based on the leader's expected path includes: taking the path point of the leader's unmanned boat as the origin, the tangent direction of the path movement as the T axis, and the normal direction as the N axis, to establish the tangent coordinate system;

[0014] Calculate the angle between the leader's path point tangent and the north direction :

[0015]

[0016] in, They are right The first-order partial derivative of and The derivative with respect to time is obtained as follows:

[0017] ;

[0018] in, is the changing speed of the path variable, that is is a function of time that satisfies By setting The leader's forward speed can be controlled, and then the forward speed of the entire formation can be controlled.

[0019] Optionally, the tangential tracking error and cross tracking error of the follower unmanned boat are calculated using the formula:

[0020] ;

[0021] For the The tangential tracking error of the follower unmanned boat in the tangent coordinate system is: For the The cross-tracking error of the follower unmanned boat in the tangent coordinate system, The real-time position of the follower unmanned boat is expressed as , It is the angle between the tangent line of the leader's path point and the north direction.

[0022] Optionally, the desired heading angle is obtained using a line of sight guidance method, expressed as:

[0023] ,in:

[0024]

[0025]

[0026] In the formula, is the desired heading angle, is the angle between the tangent line of the leader's path point and the north direction, For the The sideslip angle of the unmanned boat, They are The forward speed and lateral speed of the unmanned boat in the coordinate system, are the expected value of tangential tracking error and cross tracking error of the follower unmanned boat in the tangent coordinate system, is the line of sight term, is a positive constant, , is the parameter to be adjusted and satisfies .

[0027] Optionally, the desired combined speed is expressed as:

[0028]

[0029] In the formula, is the expected combined speed, is the change speed of the path variable, the intermediate variable ,

[0030] Optionally, the desired heading angle and the desired resultant speed are used as tracking targets, and the follower unmanned boat is controlled by a thrust controller and a rudder angle controller based on a tracking differentiator, including:

[0031] Calculating a desired heading angular velocity according to the desired heading angle;

[0032] The differential of the desired resultant velocity and the differential of the desired heading angular velocity are estimated respectively by using a tracking differentiator;

[0033] Based on the dynamic model of unmanned boat and the combined speed tracking error and the expected total velocity differential Design the thrust controller based on the estimated value of

[0034] Based on the dynamic model of unmanned boat and the heading angle tracking error and the desired heading angular velocity derivative Design the rudder angle controller based on the estimated value of

[0035] Optionally, the differential of the desired resultant velocity and the differential of the desired heading angular velocity are estimated respectively using a tracking differentiator, wherein the tracking differentiator for estimating the differential of the desired resultant velocity is expressed as:

[0036]

[0037] In the formula, is the expected total speed The estimated value of yes The estimated value of yes The derivative with respect to time, are tunable estimator parameters;

[0038] The tracking differentiator used to estimate the desired phase angular velocity derivative is expressed as:

[0039]

[0040] In the formula, is the desired heading angular velocity The estimated value of yes The estimated value of yes The derivative with respect to time, are tunable estimator parameters

[0041] Optionally, the dynamic model of the unmanned boat is expressed as:

[0042]

[0043] In the formula, The speed of the unmanned boat , lateral speed and angular velocity The time derivative, and They are the thrust controller and rudder angle controller of the follower unmanned boat. are the dynamic model parameters of the unmanned boat and can be obtained through identification.

[0044] The thrust controller is expressed as:

[0045]

[0046] In the formula, is the controller gain parameter; The expected total velocity tracking error of an unmanned boat , For the The total speed of the unmanned boats is For the The expected combined speed of the unmanned boats; yes The estimated value of yes Derivative with respect to time. Under the designed thrust control, the combined speed of the unmanned boat will accurately track the designed expected combined speed.

[0047] Optionally, the rudder angle controller is expressed as:

[0048]

[0049] In the formula, are the controller parameters to be adjusted; Heading angle tracking error of an unmanned boat , is the heading angle of the unmanned boat; the heading angular velocity tracking error , is the differential of the desired heading angular velocity, yes The estimated value of yes The derivative with respect to time. Under the designed rudder angle controller, the heading angle of the follower unmanned boat can accurately track the designed desired heading angle.

[0050] In a second aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for collaborative path tracking control of multiple unmanned boats as described in the first aspect is implemented.

[0051] Beneficial Effects

[0052] Compared with the prior art, the advantages of the present invention are:

[0053] 1) The present invention designs a new line-of-sight guidance law, and thereby designs the expected heading angle and expected combined velocity, which can ensure that the follower unmanned boat can converge to the expected position from any initial position, so that all unmanned boats can perform collaborative path tracking tasks in any initial state and can perform any formation transformation;

[0054] 2) The present invention establishes a tangential coordinate system based on the leader's path, designs the expected value of the tracking error of the followers according to the expected formation, and combines the designed expected heading angle and expected combined speed to ensure that all unmanned boats keep the formation neat at all times while tracking any path. This not only helps to improve the task completion rate, but also enhances the robustness and reliability of the unmanned boat cluster in the face of complex marine environments.

[0055] 3) Designing the unmanned boat thrust controller and rudder angle controller based on the tracking differentiator can simplify the controller design, reduce the complexity of the calculation, and is more friendly to the hardware environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 The figure is a schematic flow chart of the collaborative path tracking control method of multiple unmanned boats of the present invention;

[0057] Figure 2 The figure is a schematic diagram of a specific implementation flow of a multi-unmanned boat cooperative path tracking control method in one embodiment of the present invention;

[0058] Figure 3 The figure shows the principle diagram of the tangential tracking error and cross tracking error of the unmanned boat and their expected values ​​in the tangent coordinate system;

[0059] Figure 4 Shown is a path diagram of three unmanned boats performing collaborative path tracking in a set formation.

[0060] Figure 5 is the tangential / cross tracking error of the three unmanned boats.

[0061] Figure 6 are the expected heading angles and actual heading angles of the three unmanned boats.

[0062] Figure 7 is the expected combined speed and actual combined speed of the three unmanned boats. DETAILED DESCRIPTION

[0063] The invention is further described below with reference to the accompanying drawings and specific embodiments.

[0064] The technical concept of the present invention is: on the one hand, by designing the expected heading angle and expected resultant speed based on the new line-of-sight guidance law, it is ensured that the follower unmanned boat can converge to the expected position from any initial position, so that all unmanned boats can perform the collaborative path tracking task in any initial state and can transform into any formation. On the other hand, by establishing a tangential coordinate system based on the leader's path, the expected value of the tracking error of the follower is determined according to the expected formation, and combined with the designed expected heading angle and expected resultant speed, it is ensured that all unmanned boats keep the formation neat at all times while tracking any path.

[0065] Example 1

[0066] refer to Figure 1 The multi-unmanned boat cooperative path tracking control method of this embodiment includes:

[0067] S1, obtain the expected path information of the leader unmanned boat, describe the expected trajectory of the leader, and construct a tangent coordinate system based on the expected path of the leader;

[0068] S2, obtaining the real-time position information of the follower unmanned boat, and calculating the tangential tracking error and cross tracking error of the follower unmanned boat based on the tangent coordinate system of the leader's expected path and the real-time position information of the follower unmanned boat;

[0069] S3, according to the expected formation, obtaining the expected values ​​of the tangential tracking error and the cross tracking error of the follower unmanned boat in the tangent coordinate system;

[0070] S4, calculating an expected heading angle that can make the cross-tracking error of the follower unmanned boat converge to an expected value of the cross-tracking error, and an expected combined speed that can make the tangential tracking error converge to the expected value of the tangential tracking error;

[0071] S5, obtaining the real-time heading angle and real-time resultant speed of the follower unmanned boat, taking the desired heading angle and desired resultant speed as tracking targets, and controlling the follower unmanned boat through a thrust controller and a rudder angle controller based on a tracking differentiator.

[0072] In this embodiment, the leader unmanned boat may be a virtual leader, which is only provided for constructing the desired path and the basic tangent coordinate system.

[0073] The technical solution of this embodiment enables multiple unmanned boats to maintain a desired formation while achieving accurate path tracking.

[0074] Example 2

[0075] Based on Example 1, this example specifically introduces the implementation process of the multi-unmanned boat collaborative path tracking control method, refer to Figure 2 , which mainly includes the following contents.

[0076] S1, describes the leader’s expected path and constructs a tangent coordinate system based on the leader’s path.

[0077] S11, define the leader path function

[0078] Defining leaders on a parameterized path Move up, set is a path variable, then each path variable The coordinates of a point on the corresponding path are , and Both Related functions.

[0079] S12, construct the tangent coordinate system and calculate the angle between the tangent of the leader path point and the north direction

[0080] calculate and The derivative with respect to time is:

[0081] ;

[0082] in: is the speed of change of the path variable, which is also related to time Related functions need to be satisfied when setting By setting It can control the leader's forward speed, and then the forward speed of the entire formation; They are For path variables The first-order partial derivative of , then the angle between the moving tangent direction of the path point at this moment and the north direction is It can be calculated as:

[0083] .

[0084] S2, calculates the tangential / cross-tracking error of the follower unmanned boat based on the tangent coordinate system of the leader's path.

[0085] Describe the relative position between the leader and follower unmanned boats in the tangent coordinate system. Consider the The follower unmanned boat can obtain its own position based on the combined navigation and positioning sensor The information is used to convert the position tracking error in the world coordinate system to the tangent coordinate system, so the first Tangential / cross-tracking error of a follower unmanned boat:

[0086] ;

[0087] in: For the The tangential tracking error of an unmanned boat in the tangent coordinate system is For the Cross-tracking error of an unmanned boat in the tangent coordinate system.

[0088] S3, set the expected values ​​of tangential tracking error and cross tracking error according to the expected formation

[0089] refer to Figure 3 As shown, the tangent coordinate system is established with the leader as the origin, the path tangent direction and the normal direction as the coordinate axes, then Describes the The coordinates of the unmanned boats at the current moment in the tangent coordinate system. According to the expected formation, the first The expected position of the unmanned boat relative to the leader can be further obtained as the expected coordinates in the path tangent coordinate system. That is, according to the expected formation, the expected value of the tangential / cross-tracking error of the follower unmanned boat in the tangent coordinate system can be set .

[0090] If it can be achieved , that is, when the following equation is satisfied, multiple unmanned boats can achieve collaborative path tracking while maintaining the desired formation:

[0091] .

[0092] in: , is a very small positive number.

[0093] By changing the expected value of the tangential / cross-tracking error The formation of multiple unmanned boats can be transformed.

[0094] S4, design the expected heading angle and expected resultant speed so that the tangential / cross tracking error of the follower unmanned boat converges to the expected value set in S2.

[0095] S41, based on the kinematic equation of the unmanned boat and the tangential tracking error and cross tracking error of the follower unmanned boat calculated in S2, calculate the change rate of the tangential tracking error and the cross tracking error.

[0096] Consider the following kinematic equations of the unmanned boat:

[0097] ;

[0098] in: for The time derivative, is the heading angle of the unmanned boat, They are The forward speed, lateral speed and angular speed of the unmanned vehicle in the coordinate system.

[0099] Based on the kinematic equation of the unmanned boat, the tangential tracking error and the cross tracking error are differentiated to obtain:

[0100] ;

[0101] in: for The time derivative, For the The total speed of the unmanned boats is For the The sideslip angle of the unmanned boat, , is the angle between the path tangent and the north direction with respect to time The specific calculation process is as follows:

[0102] ;

[0103] in: is the path coordinate For path variables The second-order partial derivative of .

[0104] By tracking the error change rate, a reasonable guidance law and resultant velocity design can be achieved, so that the tangential and cross-tracking errors converge to the expected values.

[0105] S42, separating the tracking error of the desired resultant velocity and the desired heading angle in step S22

[0106] Considering the tracking errors of the desired resultant velocity and the desired heading angle, the differentials of the tangential tracking error and the cross-tracking error can be further converted to:

[0107] ;

[0108] in: for The time derivative, and Respectively The expected heading angle and expected total speed of the unmanned boat, , They are The expected heading angle tracking error and expected total speed tracking error of an unmanned boat are: and All with The relevant functions are in the following form:

[0109] ;

[0110] From the above formula, it can be found that when the heading angle tracking error and the resultant speed tracking error converge to 0, , The control target then becomes The expected heading angle of an unmanned boat and expected combined speed , so that the tangential / cross-tracking error Converges to the expected value .

[0111] S43, design the desired heading angle so that the follower unmanned boat cross-tracking error Converges to the expected value

[0112] Design of the first The expected heading angle of an unmanned boat is:

[0113] ;

[0114] in: is the designed sight line item, is a normal number, , is an adjustable parameter and satisfies the value conditions , is the hyperbolic tangent function, and its specific expression is as follows:

[0115] ;

[0116] Substitute the desired heading angle into S42 When the expected combined speed By adjusting the parameters and The value makes the cross tracking error Converge to .

[0117] The parameter setting process is as follows: First, according to the expected formation information and path variables The curvature at Calculate the disturbance variable , the disturbance variable and curvature The specific expression is as follows:

[0118] ,

[0119] .

[0120] Secondly, select appropriate parameters under the above conditions and The value meets the following conditions:

[0121] ,

[0122] The closer it is to 1, The closer it is to 2, The larger the value of , there must be a set of suitable parameters that can satisfy the above conditions.

[0123] S44, design the expected combined speed so that the tangential tracking error of the follower unmanned boat is Converges to the expected value ;

[0124] Substitute the desired heading angle into S31 In the design, the expected combined speed signal is It converges both when it is greater than 0 and when it is less than 0:

[0125] ;

[0126] The designed expected combined speed is a piecewise function, and Substituting the expected combined velocity into the S31 formula can ensure that the Tangential tracking error of a follower unmanned boat Converges to the expected value .

[0127] S5, designs a thrust controller and a rudder angle controller based on a tracking differentiator to track the desired resultant speed and desired heading angle designed in S4.

[0128] S51, calculating the desired heading angular velocity using the desired heading angle in step S4

[0129] Differentiate the desired heading angle designed in S43:

[0130] ;

[0131] in: for The time derivative, for The time derivative, for The derivative with respect to time is in the following form:

[0132] .

[0133] S52, design a tracking differentiator to estimate the differential of the desired heading angular velocity and the differential of the desired resultant velocity

[0134] Design the following tracking differentiator to estimate the differential of the desired resultant velocity:

[0135] ;

[0136] in: yes The estimated value of yes The estimated value of are the estimator parameters to be tuned.

[0137] The tracking differentiator designed as follows can also estimate the differential of the desired heading angular velocity:

[0138] ;

[0139] in: yes The estimated value of yes The estimated value of are the estimator parameters to be tuned.

[0140] Compared with directly calculating the differential or using the traditional difference method to calculate the differential, the designed tracking differentiator can accurately estimate the expected resultant velocity differential. and the desired heading angular velocity derivative , while reducing the computational complexity without amplifying sensor noise.

[0141] S53, design the thrust controller so that the combined speed of the unmanned boat keeps up with the expected combined speed

[0142] Consider the following Dynamic model of an unmanned boat:

[0143] ;

[0144] in: for The time derivative, and They are the thrust controller and rudder angle controller of the follower unmanned boat. The model parameters of the unmanned boat are obtained through identification.

[0145] Based on the dynamic model, the combined velocity tracking error and S41 The estimated value is designed as the thrust controller:

[0146] ;

[0147] in: is the controller gain parameter. Under the designed thrust control, the combined speed of the unmanned boat will accurately track the expected combined speed designed in S33.

[0148] S54, design a rudder angle controller so that the heading angle of the unmanned boat accurately tracks the desired heading angle

[0149] The heading angular velocity tracking error is defined as: .

[0150] Based on the dynamic model and heading angle tracking error in S41 and S41 The estimated values ​​of the designed rudder angle controller are as follows:

[0151] ;

[0152] in: is the controller parameter to be adjusted. Under the designed rudder angle controller, the heading angle of the follower unmanned boat can accurately track the desired heading angle designed in S32.

[0153] Effect verification

[0154] This embodiment is applied to an experimental scenario, using MATLAB 2022a as simulation software to simulate the movement of an unmanned boat in three-dimensional space. The inertial navigation sensors carried by the unmanned boat include accelerometers, magnetometers, and gyroscopes. In the simulation environment, the desired "U"-shaped path is set to: , then the path function of the virtual leader's navigation is as follows:

[0155]

[0156] Where: Path variable The initial value is set to -11, and the path variable change rate Set to 0.8m / s.

[0157] The simulation uses three unmanned boats for collaborative path tracking. In order to verify the effectiveness of the designed algorithm, the initial positions of the three unmanned boats are set at three different positions of the virtual leader: USV1 initial position: ; USV2 initial position: ; USV3 initial position: The three unmanned boats need to form an equilateral triangle formation at the beginning of the path tracking process. After 12 seconds, the formation is switched from an equilateral triangle to a straight line formation, and then from a straight line formation to an equilateral triangle at 24 seconds. The tangential / cross tracking error is set as follows according to the expected formation: equilateral triangle: ;

[0158] straight line: To prevent the impact of sudden changes in expected tangential / cross-tracking errors, the expected value has a switching time of 1 s each time the formation switches.

[0159] In the simulation environment, the parameter values ​​in the line of sight guidance law are as follows: , , ; The tracking differentiator gain is set to: , ; The controller parameters in the thrust controller and rudder angle controller are set as follows: .

[0160] Figure 3 A collaborative path tracking diagram of three unmanned boats is given. The border composed of thick black lines and white lines in the figure is a pool map. The black solid line in the figure is the moving path of the virtual leader, the black dotted line is the moving path of USV1, the black dotted line is the moving path of USV2, and the black dotted line is the moving path of USV3. It can be seen from the figure that the collaborative path tracking control method proposed in the present invention can ensure that the three unmanned boats can form a designed formation from any initial position for path tracking, and can also perform formation changes.

[0161] Figure 4 The tangential / cross tracking errors of the three unmanned boats are given. The black solid line is the tangential / cross tracking error of USV1, the dashed line is the tangential / cross tracking error of USV2, and the dotted line is the tangential / cross tracking error of USV3. Figure 4 It can be seen that after the formation switching command is issued at 12s and 24s, the tangential / cross tracking errors of the USV will change smoothly to the expected value, and there will be no unstable situations such as overshoot or jitter, which proves the effectiveness of the method proposed in the present invention.

[0162] Figure 5 The expected heading angles and tracking conditions of the three unmanned boats are given. The black solid line represents the expected heading angle of the unmanned boat given by the new line-of-sight guidance law in S32, and the black dotted line represents the actual heading angle of the unmanned boat. It can be seen from the simulation results that the two lines are almost coincident, indicating that the designed rudder angle controller can quickly and accurately track the expected heading angle.

[0163] Figure 6 The expected combined speed of the three unmanned boats and their tracking conditions are given. The black solid line represents the expected combined speed of the unmanned boat designed in S33, and the black dotted line represents the actual combined speed of the unmanned boat. It can be seen from the simulation results that the two lines are almost overlapped, indicating that the designed thrust controller can quickly and accurately track the expected combined speed.

[0164] It can be clearly seen from the above simulation results that the method of collaborative path tracking of multiple surface unmanned boats based on a novel line-of-sight guidance method proposed in the present invention can quickly and accurately track the desired path, form a desired formation and perform formation switching.

[0165] Example 3

[0166] This embodiment introduces a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the multi-unmanned boat collaborative path tracking control method as introduced in Embodiment 1 or Embodiment 2 is implemented.

[0167] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0168] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0169] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0170] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0171] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A method for cooperative path tracking control of multiple unmanned boats, characterized in that: include: Obtain the expected path information of the leader unmanned boat and construct a tangent coordinate system based on the leader's expected path; Obtain the real-time position information of the follower unmanned boat, and calculate the tangential tracking error and cross tracking error of the follower unmanned boat based on the tangent coordinate system of the leader's expected path and the real-time position information of the follower unmanned boat; According to the expected formation, the expected values ​​of the tangential tracking error and the cross tracking error of the follower unmanned boat in the tangent coordinate system are obtained; Calculating an expected heading angle that can make the cross-tracking error of the follower unmanned boat converge to an expected value of the cross-tracking error, and an expected combined speed that can make the tangential tracking error converge to the expected value of the tangential tracking error; The real-time heading angle and real-time resultant speed of the follower unmanned boat are obtained, and the desired heading angle and desired resultant speed are used as tracking targets. The follower unmanned boat is controlled by a thrust controller and a rudder angle controller based on a tracking differentiator.

2. The method according to claim 1, characterized in that: The desired path of the leader unmanned boat is represented by the path point A collection of, among which, is the path variable; and is the path point coordinate component; The construction of the tangent coordinate system based on the leader's expected path includes: taking the path point of the leader's unmanned boat as the origin, the tangent direction of the path movement as the T axis, and the normal direction as the N axis, to establish the tangent coordinate system; Calculate the angle between the leader's path point tangent and the north direction : ， in, They are right The first-order partial derivative of and The derivative with respect to time is obtained as follows: ； in, is the changing speed of the path variable, that is is a function of time that satisfies .

3. The method according to claim 2, characterized in that: The formula for calculating the tangential tracking error and cross tracking error of the follower unmanned boat is: ； For the The tangential tracking error of the follower unmanned boat in the tangent coordinate system is: For the The cross-tracking error of the follower unmanned boat in the tangent coordinate system, The real-time position of the follower unmanned boat is expressed as .

4. The method according to claim 3, characterized in that: The desired heading angle is obtained using the line of sight guidance method and is expressed as: ,in: ， ， In the formula, is the desired heading angle, is the angle between the tangent line of the leader's path point and the north direction, For the The sideslip angle of the unmanned boat, They are The forward speed and lateral speed of the unmanned boat in the coordinate system, are the expected value of tangential tracking error and cross tracking error of the follower unmanned boat in the tangent coordinate system, is the line of sight term, is a normal number, , is the parameter to be adjusted and satisfies .

5. The method according to claim 4, characterized in that: The desired combined speed is expressed as: ， In the formula, is the expected combined speed, is the change speed of the path variable, the intermediate variable .

6. The method according to claim 5, characterized in that: The method uses the desired heading angle and the desired resultant speed as tracking targets, and controls the follower unmanned boat through a thrust controller and a rudder angle controller based on a tracking differentiator, including: Calculating a desired heading angular velocity according to the desired heading angle; The differential of the desired resultant velocity and the differential of the desired heading angular velocity are estimated respectively by using a tracking differentiator; Based on the dynamic model of unmanned boat and the combined speed tracking error and the expected total velocity differential Design the thrust controller based on the estimated value of Based on the dynamic model of unmanned boat and the heading angle tracking error and the desired heading angular velocity derivative Design the rudder angle controller based on the estimated value of 7. The method according to claim 6, characterized in that: The tracking differentiator is used to estimate the differential of the desired resultant velocity and the differential of the desired heading angular velocity, respectively, wherein the tracking differentiator used to estimate the differential of the desired resultant velocity is expressed as: ， In the formula, is the expected total speed The estimated value of yes The estimated value of are tunable estimator parameters; The tracking differentiator used to estimate the desired phase angular velocity derivative is expressed as: ， In the formula, is the desired heading angular velocity The estimated value of yes The estimated value of are tunable estimator parameters.

8. The method according to claim 7, characterized in that: The dynamic model of the unmanned boat is expressed as: ， In the formula, The speed of the unmanned boat , lateral speed and angular velocity The time derivative, and They are the thrust controller and rudder angle controller of the follower unmanned boat. are the dynamic model parameters of the unmanned boat; The thrust controller is expressed as: ， In the formula, is the controller gain parameter; The expected total velocity tracking error of an unmanned boat , For the The total speed of the unmanned boats is For the The expected combined speed of the unmanned boats; yes The estimated value of yes Derivative with respect to time.

9. The method according to claim 7, characterized in that: The dynamic model of the unmanned boat is expressed as: ， In the formula, The speed of the unmanned boat , lateral speed and angular velocity The time derivative, and They are the thrust controller and rudder angle controller of the follower unmanned boat. are the dynamic model parameters of the unmanned boat; The rudder angle controller is expressed as: ， In the formula, are the controller parameters to be adjusted; Heading angle tracking error of an unmanned boat , is the heading angle of the unmanned boat; the heading angular velocity tracking error , is the differential of the desired heading angular velocity, yes The estimated value of yes Derivative with respect to time.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the multi-unmanned boat collaborative path tracking control method as described in any one of claims 1-9 is implemented.

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