A method for tracking the trajectory of a surface vessel

Abstract

The present invention provides a method for controlling the trajectory tracking of a surface boat, and the method includes: constructing a boat motion model in a geodetic coordinate system, determining the boat position tracking error in the boat coordinate system, and determining the heading error of the boat; determining a combined velocity auxiliary variable based on the desired coordinates of the boat and the heading error; constructing the desired forward velocity, the desired combined velocity auxiliary variable, and the desired yaw angular velocity of the boat; constructing a surge virtual variable and a yaw virtual variable; constructing a relaxation condition of a single-parameter adaptive method based on the surge virtual variable and the yaw virtual variable; constructing a stability analysis model based on the relaxation condition and a preset adaptive update law, so as to obtain the forward thrust and the yaw moment of the boat based on the stability analysis model and the backstepping method. Without relying on any model dynamic information, the present invention solves the problem of heavy computational load in the process of boat motion control and realizes precise tracking.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic control, and particularly relates to a method for tracking the trajectory of a surface vessel. Background Art

[0002] With the increasing attention of countries around the world to marine commerce, science, and military issues, surface vessels are widely used in marine engineering, such as marine resource development, maritime search and rescue, patrol and reconnaissance, etc. Under this background, the requirements for the maneuverability of surface vessels have also increased accordingly. The problem of surface vessel trajectory tracking is restricted by space and time, and it is required to reach the desired position within a specified time. Therefore, in a complex marine environment, surface vessel trajectory tracking is an important prerequisite for completing various tasks and is also a research hotspot in the field of ship motion control.

[0003] In navigation practice, due to factors such as external disturbances, model perturbations, unmodeled dynamics, and nonlinear uncertainties, surface vessel trajectory tracking faces huge challenges. To overcome these difficulties, relevant methods have been applied to the field of surface vessel motion control, including: sliding mode control, backstepping-based and dynamic surface control, etc. However, sliding mode control will cause chattering problems, and backstepping-based control requires the system to have dynamics. In addition, many results have been combined with fuzzy logic systems, neural networks, and fuzzy neural networks to propose many intelligent solutions for dealing with system uncertainties. However, the design process of the above control schemes depends on partial known information of the vessel system model. The methods based on neural networks and fuzzy neural networks will lead to heavy computational burdens. At the same time, limited by the approximation principle, adaptive neural / fuzzy cannot accurately approximate environmental disturbances. Summary of the Invention

[0004] In view of the deficiencies of the above-mentioned prior art, it is necessary to provide a method for tracking the trajectory of a surface vessel, which generalizes the coordinate reversible linear transformation method to the case without model parameters, overcomes the limitations of implicit assumptions in the LOS-based scheme, and solves the technical problem of heavy computational burden in the process of vessel trajectory tracking.

[0005] To achieve the above object, the present invention provides a method for tracking the trajectory of a surface vessel, including:

[0006] Construct a vessel motion model in the earth coordinate system, and based on the vessel motion model and the desired coordinates of the vessel in the earth coordinate system, determine the vessel position tracking error in the vessel coordinate system, and based on the vessel motion model and the desired heading angle, determine the heading error of the vessel;

[0007] Based on the desired coordinates of the vessel and the heading error, determine the combined velocity auxiliary variable; wherein, the formula for the combined velocity auxiliary variable is:

[0008] Construct the desired forward speed, the desired combined speed auxiliary variable, and the desired yaw angular velocity of the boat to achieve the convergence of the boat position tracking error, the error of the combined speed auxiliary variable, and the heading error;

[0009] Construct the surge virtual variable and the yaw virtual variable;

[0010] Based on the surge virtual variable and the yaw virtual variable, construct the relaxation condition of the single-parameter adaptive method;

[0011] Based on the relaxation condition and the preset adaptive update law, construct a stability analysis model to obtain the forward thrust and the yaw moment of the boat based on the stability analysis model and the backstepping method, so as to achieve boat trajectory tracking based on the forward thrust and the yaw moment.

[0012] Further, h = Usinψ e , where h is the combined speed auxiliary variable, x d and y d are the desired coordinates of the boat, ψ e is the heading error.

[0013] Further, construct the desired forward speed, the desired combined speed auxiliary variable, and the desired yaw angular velocity of the boat based on the following formula:

[0014] u d = -k1z1 + Ucos(ψ e )

[0015] h d = -k2z2 - v

[0016]

[0017] where u e = u - u d , h e = h - h d , r e = r - r d , u d is the desired forward speed, h d is the desired combined speed auxiliary variable, r d is the desired yaw angular velocity, u is the forward speed variable in the boat motion model, v is the lateral speed variable in the boat motion model, r is the angular velocity variable in the boat motion model, ψ d is the desired heading of the boat in the earth coordinate system, k1 is the first design parameter, k2 is the second design parameter, k3 is the third design parameter, and the first design parameter, the second design parameter, and the third design parameter are all greater than zero.

[0018] Furthermore, construct the surge virtual variable based on the following formula:

[0019]

[0020] where Lu is the surge virtual variable, du is the interference of the boat's forward speed, is the derivative of the desired forward speed, z1 is the boat position tracking error, m 11 is the first inertia mass of the boat, m 22 is the second inertia mass of the boat, d 11 is the first hydrodynamic damping coefficient.

[0021] Furthermore, construct the yaw virtual variable based on the following formula:

[0022]

[0023] where Lr is the yaw virtual variable, is the virtual yaw angular velocity, ψ e is the heading error, τ dr is the boat angular velocity interference, τ dv is the boat lateral speed interference, m 33 is the third inertia mass of the boat, d 22 is the second hydrodynamic damping coefficient, d 33 is the third hydrodynamic damping coefficient.

[0024] Furthermore, construct the relaxation condition based on the following formula:

[0025]

[0026]

[0027] where,

[0028]

[0029]

[0030] Furthermore, construct the adaptive update law based on the following formula:

[0031]

[0032]

[0033] where σ i>0 (where \(i = 0, 1, 2, 3\) are preset parameters, is the estimated value of, is the estimated value of.

[0034] Furthermore,

[0035]

[0036] where \(g\) is a preset constant, satisfying \(0\leq g\leq\min\{p3, p6\}\).

[0037] Furthermore, the stability analysis model is:

[0038]

[0039] Furthermore, the forward thrust and yaw moment of the boat are obtained based on the following formula, including:

[0040]

[0041]

[0042] where \(\tau\) u is the forward thrust, and \(\tau\) r is the yaw moment.

[0043] The beneficial effects of adopting the above implementation method are as follows: The watercraft trajectory tracking method provided by the present invention designs a combined velocity auxiliary variable to solve the potential singularity problem caused by the underactuated characteristics. At the same time, the method based on coordinate reversible transformation is extended to the case without model parameter information, expanding the application scenario of this type of method. Based on the trajectory tracking control strategy with single linear parameters, in the power design loop of the watercraft, the uncertain terms caused by environmental disturbances in the surge and sway directions are transformed into the form of a single linear unknown parameter, so that there are not too many unknown variables involved in the control unit, effectively reducing the computational burden and solving the technical problem of heavy computational workload during the watercraft trajectory tracking process. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative efforts.

[0045] Figure 1 is a schematic flowchart of an embodiment of the watercraft trajectory tracking method provided by the present invention;

[0046] Figure 2 The three-degree-of-freedom motion diagram of the underactuated surface vessel provided by the present invention;

[0047] Figure 3 The effect diagram of the tracking trajectory of the simulation experiment provided by the present invention;

[0048] Figure 4 The principle block diagram of an embodiment of the surface vessel trajectory tracking method provided by the present invention;

[0049] Figure 5 The preset path and actual tracking position diagram provided by the present invention;

[0050] Figure 6 The tracking trajectory error diagram of the simulation experiment provided by the present invention;

[0051] Figure 7 The propeller thrust and torque diagram provided by the present invention;

[0052] Figure 8 The velocity diagram of the underactuated ocean surface vessel in three degrees of freedom provided by the present invention;

[0053] Figure 9 The external uncertainty estimation diagram provided by the present invention. Detailed implementation manners

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0055] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "plural" is two or more.

[0056] In the embodiments of the present invention, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or equipment that includes a series of steps or modules does not necessarily have to be limited to those clearly listed steps or modules, but may include other steps or modules that are not clearly listed or are inherent to these processes, methods, products or equipment.

[0057] In the embodiments of the present invention, the naming or numbering of the steps does not mean that the steps in the method flow must be executed in the time / logical order indicated by the naming or numbering. The named or numbered process steps can change the execution order according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0058] As used herein, the term "embodiment" means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appearing at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0059] The present invention provides a method for tracking the trajectory of a surface vessel, which will be described separately below.

[0060] As Figure 1 shown, the present invention provides a method for tracking the trajectory of a surface vessel, including:

[0061] Step 110: Construct a vessel motion model in the earth coordinate system, and based on the vessel motion model and the desired coordinates of the vessel in the earth coordinate system, determine the position tracking error of the vessel in the vessel coordinate system, and based on the vessel motion model and the desired heading angle, determine the heading error of the vessel.

[0062] It can be understood that in this embodiment, a reversible coordinate transformation method for the vessel stability error is adopted to represent the stability error in the earth coordinate system in the vessel fixed coordinate system to address the problem of underactuation of the vessel.

[0063] The vessel motion model is as follows:

[0064]

[0065] [[ID=!26]]

[0066] where (x, y) and ψ respectively represent the position and heading of the vessel in the earth coordinate system, as Figure 2 shown. Specifically, the vectors u, v, and r are respectively the forward speed variable, lateral speed variable, and angular velocity variable of the vessel; τ u , τ r respectively represent the forward thrust and torque of the vessel; m 11 , m 22 , m 33 are the inertial masses of the vessel in three different directions; d 11 , d 22 , d 33 represent the hydrodynamic damping coefficients in three different directions; τ du , τ dv , τ dr represent the equivalent disturbing forces and torques caused by the unknown time-varying ocean environmental disturbances on the vessel.

[0067] Assume that the boat information m(·) and d(·) are unknown; the ocean environmental disturbances are unknown; the preset trajectory η d =[x d ,y d ,ψ d T is smooth and bounded, and its first - order derivative and second - order derivative are bounded; the lateral velocity is passively bounded, that is, there exists an unknown constant B0 such that for any time t≥0, sup|v(t)|≤B0.

[0068] Define the stability error x e =x - x d ,y e =y - y d ,ψ e =ψ - ψ d .

[0069] where [x d ,y d T is the expected coordinate position of the boat, and the expected yaw angular velocity is expressed as

[0070] Express the boat position tracking errors z1 and z2 in the boat coordinate system:

[0071]

[0072] The above formula uses a reversible coordinate transformation method to represent the stability error in the geodetic coordinate system in the boat fixed coordinate system. Based on the above formula, the differential equation of the new system is obtained, which is expressed as follows:

[0073]

[0074] where

[0075]

[0076] where

[0077] Step 120: Determine the combined velocity auxiliary variable based on the boat expected coordinates and the heading error; where the formula for the combined velocity auxiliary variable is: h = Usinψ e , h is the combined velocity auxiliary variable, x d and y d are the boat expected coordinates, and ψ e is the heading error.

[0078] ​​It can be understood that the introduction of the sway velocity can be avoided, thereby avoiding the continuous excitation condition that depends on u≠0, and solving the singularity problem caused by the initial state constraint.

[0079] Taking u and h as virtual control inputs, design the desired control laws for both u d and h d to achieve the convergence of z1 and z2.

[0080] Step 130: Construct the desired forward velocity, desired combined velocity auxiliary variable, and desired yaw angular velocity of the boat to achieve the convergence of the boat position tracking error, the error h e of the combined velocity auxiliary variable e and the heading error ψ.

[0081] It can be understood that after obtaining the desired forward velocity, taking the derivative of the desired forward velocity, the derivative of the desired forward velocity does not contain any unknown model parameters. After obtaining the desired angular velocity, taking the derivative of the desired angular velocity, the derivative of the desired angular velocity contains unknown model parameters, such as including and further there are unknown model parameters b, c, and d. The unknown model parameters are a design obstacle to the present invention, so it is necessary to construct a virtual yaw angular velocity to eliminate the influence of the unknown model parameters. The water surface boat trajectory tracking method provided by the present invention does not contain any unknown model parameters.

[0082] Step 140: Construct the surge virtual variable and the yaw virtual variable;

[0083] Design the surge virtual variable Lu and the yaw virtual variable Lr in the surge and yaw directions respectively.

[0084] It can be understood that the surge virtual variable Lu is also the virtual variable of the boat in the surge direction, and the yaw virtual variable Lr is also the virtual variable of the boat in the yaw direction. Convert the uncertain terms caused by model perturbation and environmental disturbance in the surge and yaw directions in the dynamic subsystem design loop into the form of single linear parameters, reducing the calculation burden.

[0085] Step 150: Based on the surge virtual variable and the yaw virtual variable, construct the relaxation condition of the single-parameter adaptive method.

[0086] It can be understood that the single-parameter adaptive control method refers to online identifying the parameters of the ship motion model and correcting the characteristics of the ship controller itself to adapt to the changes in the dynamic characteristics of the object and the disturbance. It only includes a smoothing constant. The water surface boat trajectory tracking method provided by the present invention uses the single-parameter adaptive method to track the boat trajectory.

[0087] Step 160: Based on the relaxation condition and a preset adaptive update law, construct a stability analysis model to obtain the forward thrust and yaw moment of the boat based on the stability analysis model and the backstepping method, so as to achieve boat trajectory tracking based on the forward thrust and the yaw moment.

[0088] It can be understood that the designed combined velocity auxiliary variable solves the potential singularity problem caused by the underactuated characteristics. At the same time, the method based on coordinate reversible transformation is extended to the case without model parameter information, expanding the application scenario of this type of method. Based on the trajectory tracking control strategy with single linear parameters, in the dynamic design loop of the surface boat, the uncertain terms caused by environmental disturbances in the surge and sway directions are transformed into the form of a single linear unknown parameter, so that there are not too many unknown variables in the control unit, effectively reducing the computational burden and solving the technical problem of heavy computational load in the process of boat trajectory tracking.

[0089] In some embodiments, define u e = u - u d , h e = h - h d and r e = r - r d , which represent the boat velocity error variables.

[0090] Select the Lyapunov function and take the derivative for convenient stability analysis.

[0091] Design the desired velocity:

[0092] u d = -k1z1 + Ucos(ψ e )

[0093] h d = -k2z2 - v

[0094]

[0095] where k1, k2, k3 are design parameters and are all greater than zero.

[0096] Take the derivative of u d and r d in the above formula. Given that does not contain any model parameters, the last term contains that is, there are unknown model information b, c, and d. Obviously, these uncertain terms in

[0097] Define the virtual yaw angular velocity as shown below:

[0098]

[0099] Combining the above formula, and The design of the present invention can be directly applied.

[0100] In some embodiments, constructing a surge dummy variable using the vessel position tracking error includes:

[0101] Design of Lyapunov function With stable error variable u e and r e :

[0102]

[0103] Combining the above formula, we can see that there is a lot of unknown model information, and construct the surge virtual variable:

[0104]

[0105] Where Lu is the sloshing virtual variable, u is the forward speed variable, v is the lateral speed variable, r is the angular velocity variable, τ du The forward speed of the boat is disturbed. is the derivative of the desired forward speed, z1 is the vessel position tracking error, m 11 is the first inertial mass of the boat, m 22 is the second inertial mass of the boat, d 11 is the first hydrodynamic damping coefficient.

[0106] In some embodiments, the yaw dummy variable is constructed based on the following formula:

[0107]

[0108] Wherein, Lr is the yaw dummy variable, x d 、y d are the desired horizontal and vertical coordinates of the boat, is the virtual yaw angular velocity, ψ e is the heading error, τ dr is the ship angular velocity disturbance, τ dv is the ship's lateral velocity disturbance, k3 is the preset third design parameter, m 33 is the third inertial mass of the boat, d 22 is the second hydrodynamic damping coefficient, d 33 is the third hydrodynamic damping coefficient.

[0109] In some embodiments, constructing the relaxation conditions of the single-parameter adaptive method includes:

[0110] Given that Lu and Lr are unknown and cannot be directly used for control law design. At the same time, Lu and Lr contain many unknown variables. To avoid the problem of computational burden, Lu and Lr are transformed as follows:

[0111]

[0112]

[0113] Among them,

[0114]

[0115]

[0116] Based on the above transformation, the relaxation conditions of the single-parameter adaptive method are obtained.

[0117] In some embodiments, the adaptive update law of the single-parameter adaptive method is constructed based on the following formula:

[0118]

[0119]

[0120] Among them, σ i >0 (i = 0, 1, 2, 3 are preset parameters, is the estimated value of θ1, is the estimated value of θ2.

[0121] Define the estimation error:

[0122]

[0123] Among them, g is a constant satisfying 0 ≤ g ≤ min{p3, p6}.

[0124] In some embodiments, the stability analysis model is:

[0125]

[0126] Take the derivative of V3, and then substitute the relaxation conditions and adaptive update law of the single-parameter adaptive method, as well as the defined estimation error, into the following formula to obtain the stability analysis model in this embodiment:

[0127]

[0128] Next, design τ using the idea of backstepping design u and τ r:

[0129]

[0130]

[0131] where, τ u is the forward thrust, and τ r is the yaw moment.

[0132] In the above formula, τ u and τ r will be used to effectively and real-time control the boat to navigate on the preset trajectory.

[0133] Furthermore, a simulation experiment is conducted on the method provided by the present invention to verify the effectiveness of the present invention. The simulation experiment method is as follows:

[0134] To make the simulation results more credible, a combination of a straight line and a curve is selected as the preset trajectory, and the initial position is set, as Figure 3 shown.

[0135] The specific data of the experimental boat model information selected are: m 11 = 200 kg, m 22 = 250 kg, m 33 = 80 kg·m 2 , d 11 = 70 kg / s, d 22 = 100 kg / s, d 33 = 50 kg·m 2 / s. The boat model information is not limited to the values here.

[0136] Design the external time-varying disturbance where is a first-order Markov process, Ξ ∈ R 3 is zero-mean Gaussian white noise, Υ ∈ R 3×3 is a diagonal constant matrix. Let Φ(0) = [0.5, 0.5, 0.5] T , Φ = diag(2, 2, 2), Ξ = diag(3, 2, 2), d = [0.6(sin(0.02πt + π / 4) + cos(0.01πt)); (cos(0.02πt - π / 8) - sin(0.05πt)); (sin(0.01πt + π / 3)cos(0.01πt))].

[0137] The design parameters of the present invention are: k1 = 2, k2 = 2, k3 = 2, c1 = 0.1, c2 = 0.4, g = 0.001, σ1 = 10, σ2 = 0.05, σ3 = 10, σ4 = 0.0001.

[0138] Simulink simulation environment setup.

[0139] In some other embodiments, the principle of the watercraft trajectory tracking method provided by the present invention is as Figure 4 shown. In this embodiment, the preset path and the actual tracking position are as Figure 5 shown. The error of the tracking trajectory in the simulation experiment is as Figure 6 shown. Compared with other methods, the error is smaller. In this embodiment, the thrust and torque of the watercraft propeller are as Figure 7 shown. The velocities of the underactuated ocean watercraft in the three degrees of freedom directions are as Figure 8 shown. The estimation of the external uncertain terms is as Figure 9 shown.

[0140] In addition, for the watercraft trajectory tracking method provided by the present invention, at the same time, the method based on coordinate reversible transformation is extended to the case without model parameter information, expanding the application scenarios of this type of method. Based on the trajectory tracking control strategy with single linear parameters, in the power design loop of the watercraft, the uncertain terms caused by environmental disturbances in the surge and sway directions are transformed into the form of a single linear unknown parameter, so that there are not too many unknown variables involved in the control unit, effectively reducing the computational burden. The present invention also considers the uncertainty of the unmanned watercraft system and external time-varying disturbances, etc., improving the safety and anti-interference ability during the trajectory tracking of the underactuated watercraft.

[0141] The above has introduced the watercraft trajectory tracking provided by the present invention in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A surface vessel trajectory tracking method, characterized in that: include: Constructing a vessel motion model in a geodetic coordinate system, and determining a vessel position tracking error in the vessel coordinate system based on the vessel motion model and desired vessel coordinates in the geodetic coordinate system, and determining a vessel heading error based on the vessel motion model and desired heading angle; Based on the desired coordinates of the vessel and the heading error, a resultant velocity auxiliary variable is determined; wherein the formula for the resultant velocity auxiliary variable is: Constructing a desired forward speed of the vessel, a desired resultant velocity auxiliary variable, and a desired yaw angular velocity to achieve convergence of the vessel position tracking error, the error of the resultant velocity auxiliary variable, and the heading error; Construct dummy variables for surge and pitch; Based on the surge dummy variable and the yaw dummy variable, a relaxation condition of a single-parameter adaptive method is constructed; Based on the relaxation condition and the preset adaptive update law, a stability analysis model is constructed to obtain the forward thrust and bow pitch moment of the boat based on the stability analysis model and the backstepping method, so as to achieve boat trajectory tracking based on the forward thrust and the bow pitch moment.

2. The surface vessel trajectory tracking method according to claim 1, characterized in that: h=Usinψ e , h is the auxiliary variable of the resultant speed, x d and y d is the desired coordinate of the boat, ψ e is the heading error.

3. The surface vessel trajectory tracking method according to claim 2, characterized in that: The expected forward speed of the boat, the expected resultant speed auxiliary variable, and the expected yaw angular velocity are constructed based on the following formula: u d =-k1z1+Ucos(ψ e ) h d =-k2z2-v Among them, u e =uu d , h e =hh d , r e =rr d ,u d is the expected forward speed, h d is the auxiliary variable of the desired resultant speed, r d is the desired yaw angular velocity, u is the forward velocity variable in the boat motion model, v is the lateral velocity variable in the boat motion model, r is the angular velocity variable in the boat motion model, ψ d is the expected heading of the vessel in the geodetic coordinate system, k1 is a first design parameter, k2 is a second design parameter, k3 is a third design parameter, and the first design parameter, the second design parameter and the third design parameter are all greater than zero.

4. The surface vessel trajectory tracking method according to claim 3, characterized in that: The sloshing dummy variable is constructed based on the following formula: Wherein, Lu is the dummy variable for longitudinal surge, du The forward speed of the boat is disturbed. is the derivative of the desired forward speed, z1 is the vessel position tracking error, m 11 is the first inertial mass of the boat, m 22 is the second inertial mass of the boat, d 11 is the first hydrodynamic damping coefficient.

5. The surface vessel trajectory tracking method according to claim 4, characterized in that: The yaw dummy variable is constructed based on the following formula: Wherein, Lr is the yaw dummy variable, is the virtual yaw angular velocity, ψ e is the heading error, τ dr is the ship angular velocity disturbance, τ dv is the ship's lateral velocity disturbance, m 33 is the third inertial mass of the boat, d 22 is the second hydrodynamic damping coefficient, d 33 is the third hydrodynamic damping coefficient.

6. The surface vessel trajectory tracking method according to claim 5, characterized in that: The relaxation condition is constructed based on the following formula: in, 7. The surface vessel trajectory tracking method according to claim 6, characterized in that: The adaptive update law is constructed based on the following formula: Among them, σ i >0, i=0,1,2,3 are preset parameters, is the estimated value of θ1, is the estimated value of θ2.

8. The surface vessel trajectory tracking method according to claim 7, characterized in that: Wherein, g is a preset constant that satisfies 0≤g≤min{p3,p6}.

9. The surface vessel trajectory tracking method according to claim 6, characterized in that: The stability analysis model is:

10. The surface vessel trajectory tracking method according to claim 9, characterized in that: The forward thrust and bow moment of the boat are obtained based on the following formulas: Among them, τ u is the forward thrust, τ r is the yaw moment.

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