Unmanned ship target tracking constraint control method based on exponential time-varying performance function

Abstract

The invention discloses an unmanned ship target tracking constraint control method based on an exponential time-varying performance function, and relates to the technical field of state tracking control, in particular to the technical field of performance constraint control, comprising the following steps: step (1), establishing an unmanned ship motion three-degree-of-freedom mathematical model; step (2): constructing an exponential time-varying function; (3) constructing an exponential time-varying performance function; (4) introducing a time-varying auxiliary function; (5) designing a transfer function; (6) designing a fixed time performance constraint heading controller based on an exponential time-varying performance function; (7) designing a fixed time performance constraint surging controller based on an exponential time-varying performance function; and (8) performing simulation verification. According to the method, mainly starting from the design of a novel time-varying performance function, the problem that the state error of the traditional performance function constraint control at the initial moment is limited by the performance boundary is solved, so that the transient performance and the steady-state performance of the state tracking error of the unmanned ship are remarkably improved; and the overall control performance of unmanned ship target tracking control is further improved.

Description

Technical fields:

[0001] This invention relates to the field of target tracking technology, and in particular to a target tracking constraint control method for unmanned surface vessels based on an exponential time-varying performance function.

[0002] Background Technology: Unmanned surface vessels (USVs) are specialized unmanned surface platforms with autonomous navigation, obstacle avoidance, and environmental information detection capabilities. Among numerous marine unmanned equipment, they are increasingly valued for their strong autonomy, high reliability, and low cost, playing a vital role in both military and civilian fields. In USV systems, the navigation control system is the core component, mainly comprising the guidance system, navigation system, and control system. As a key technology for USV navigation, the control system further includes research on motion control related to dynamic positioning, trajectory tracking, path following, and target tracking.

[0003] Target tracking determines the target's direction and velocity based on instantaneous target state information and performs real-time tracking. For example, in numerous maritime missions such as target pursuit and escort, unmanned surface vessels (USVs) need to track targets. As the demands on USVs in maritime missions continue to increase, researching how to achieve higher-performance motion control for USVs under multiple constraints has become a hot topic. Existing constraint control methods include nonlinear mapping function-based constraint control, Lyapunov function-based constraint control, and performance function-based constraint control. Among these, the performance function constraint control method essentially uses a state amplifier, mapping the state tracking error to constraint error. When the tracking error approaches the performance envelope edge, the constraint error tends to infinity, causing the controller to output a larger control signal to quickly correct the tracking error. Since exponential functions have good decay performance, most common performance functions are designed based on exponential functions to further improve the transient and steady-state performance of USV controllers.

[0004] However, in existing research on performance function constraint control for unmanned surface vessel (USV) target tracking, there is still a problem that the state tracking error constraint adjustment is inflexible due to the constant change in the relative position of the USV to the target at the initial moment. Therefore, this invention mainly starts from designing a novel time-varying performance function to solve the problem that the state error of traditional performance function constraint control is limited by the performance boundary at the initial moment, thereby further improving the overall performance of USV target tracking control. Summary of the Invention:

[0005] The present invention relates to the implementation of a target tracking constraint control method for unmanned surface vessels based on an exponential time-varying performance function.

[0006] The objective of this invention is achieved as follows:

[0007] A target tracking constraint control method for unmanned surface vessels based on an exponential time-varying performance function includes the following steps:

[0008] Step (1): Establish a three-degree-of-freedom mathematical model of the unmanned surface vessel's motion:

[0009] Based on the motion of the unmanned surface vessel (USV) on the water surface, a three-degree-of-freedom mathematical model of the USV is established in both a fixed coordinate system and a ship coordinate system, considering its pitch, sway, and bow angular velocities. This model includes a three-degree-of-freedom kinematic model and a three-degree-of-freedom dynamic model: The three-degree-of-freedom model of the USV in the fixed coordinate system is as follows:

[0010]

[0011] A three-degree-of-freedom model of an unmanned surface vessel in the ship's coordinate system:

[0012]

[0013] In the above formula, x, y, and ψ represent the northward, eastward, and bow angles of the unmanned surface vessel (USV) in a fixed coordinate system, respectively; u, v, and r represent the pitch velocity, sway velocity, and bow angular velocity of the USV, respectively; m 11 ,m 22 ,m 33 The mass m represents the inherent mass of the unmanned surface vessel. 23 ,m 32 Represents the added mass of the unmanned surface vessel; Coriolis matrix and damping matrix, parameter C 13 =-C 31 =-m 22 vm 22 r, C 32 =-C 23 =m 11 u, D 11 D 22 D 23 D 32 and D 33 τ is the hydrodynamic damping parameter. u ,τ r These represent the sway controller and the heading controller, respectively.

[0014] Step (2): Construct an exponential time-varying function:

[0015] An exponential time-varying function is constructed to facilitate flexible adjustment of the constrained steady-state time for the state error of the unmanned surface vessel. The specific form of the constructed function is as follows: Where n > 0 and T > 0 is the user-defined adjustment time;

[0016] Step (3): Construct the exponential time-varying performance function:

[0017] Based on the time-varying function in step (2), an exponential time-varying performance function is constructed to constrain the control performance of the unmanned surface vessel's state error. The specific form of the constructed function is as follows: Where t > 0 and ε = 0.

[0018] The constructed exponential time-varying performance function γ(t) is a smoothly decreasing function with the following properties:

[0019] 1) When t≥T, γ(t)=1 and

[0020] 2) For t > 0, γ i (t)(i=1,2,...,n) is continuously differentiable.

[0021] Step (4): Introduce a time-varying auxiliary function:

[0022] The introduction of a time-varying auxiliary function lays the groundwork for the subsequent construction of a new state error system for unmanned surface vessels. The specific form of the constructed time-varying auxiliary function is as follows: Where 0 < b << 1. The introduced time-varying auxiliary function has the following properties:

[0023] 1) When t≥T, β(t)=1 / b and β(0)=1;

[0024] 2) For t > 0, β i (t)(i=1,2,...,n) is continuously differentiable;

[0025] 3) When t≥T, β n+1 (t) is continuous and bounded.

[0026] Therefore, the constructed auxiliary variable is: ζ l (t)=β(t)z l (t), where z l (t)=ll d Let l represent the original state error of the unmanned surface vessel and l∈{u,ψ,r}.

[0027] Step (5): Design the transformation function:

[0028] Design a transformation function to obtain a new system s for the state error of the unmanned surface vessel. l (t), constraining the new system of state error of the unmanned surface vessel, the specific form of the designed transformation function is expressed as:

[0029]

[0030] Taking its first derivative, we get: s l ∈{s u ,sψ ,s r},in and These are respectively represented as the first-order partial derivatives of the transformation function with respect to the state error variable, the time-varying auxiliary function, and the exponential time-varying performance function. Therefore, the unmanned surface vessel system is unaffected by the initial value z of the original state error. l Under the constraint (0), the original state error satisfies the following constraint condition: -γ l (t) / β(t)<z l (t)<γ l (t) / β(t).

[0031] Step (6): Design a fixed-time performance-constrained forward controller based on an exponential time-varying performance function:

[0032] Based on the transformed second-order heading dynamic error subsystem obtained in step (5), a virtual control input r is designed. d And a fixed-time performance-constrained forward controller based on an exponential time-varying performance function.

[0033] Define the error variable:

[0034] z ψ =ψ-ψ d ;

[0035] z r =rr d ;

[0036] In the above formula, ψ d It is the reference bow angle of the unmanned surface vessel; z ψ It is the heading angle tracking error; z r It is the heading angular velocity tracking error; r d It is a fixed-time virtual control input.

[0037] Combining the unmanned surface vessel model established in steps (5) and (1), the error dynamics based on the new bow subsystem can be obtained as follows:

[0038]

[0039] Design a fixed-time virtual control input r d and fixed-time performance-constrained forward controller τ r as follows:

[0040]

[0041] In the above formula, 0 < λ1 < 1, λ2 > 1, All represent positive parameters to be designed. Let be the first derivative of the desired heading angle of the unmanned surface vessel.

[0042] Step (7): Design a fixed-time performance-constrained oscillation controller based on an exponential time-varying performance function:

[0043] Based on the transformed first-order sway dynamic error new system obtained in step (5), a fixed-time performance constraint sway controller based on an exponential time-varying performance function is designed using the backstepping recursive control method.

[0044] Define the error variable:

[0045] z u =uu d ;

[0046] In the above formula, u d This indicates the expected pitching speed of the unmanned surface vessel.

[0047] Combining the unmanned surface vessel model established in steps (5) and (1), the error dynamics based on the new longitudinal oscillation subsystem can be obtained as follows:

[0048]

[0049] Design a fixed-time performance-constrained forward controller τ u as follows:

[0050]

[0051] In the above formula, All of these are positive parameters to be designed, and 0 < λ1 < 1 and λ2 > 1 are both parameters to be designed.

[0052] Step (8): Simulation verification:

[0053] The fixed-time performance-constrained heading controller and sway controller based on the exponential time-varying performance function designed in steps (1) to (8) were simulated on an underactuated unmanned surface vessel.

[0054] The present invention has the following beneficial effects:

[0055] The present invention describes a fixed-time performance constraint control method for unmanned surface vessel (USV) target tracking based on an exponential time-varying performance function. This method addresses the adverse effects of USV state tracking errors on the transient and steady-state performance of the USV controller during target tracking. By constructing an exponential time-varying performance function, the original state error of the USV is processed and incorporated into the transformation function to construct a new USV state error system. This achieves global performance constraints on the USV state error, solving the problem of limited initial time constraints in traditional preset performance constraint control. It significantly improves the transient and steady-state performance of the USV target tracking control system and enhances the robustness of the control system. Attached image description:

[0056] Figure 1 This is a flowchart of the steps described in this invention;

[0057] Figure 2 This is a structural diagram of the unmanned surface vessel target tracking system described in this invention;

[0058] Figure 3 This is a graph of the relevant function designed under this invention;

[0059] Figure 4 The diagram shows the state variable tracking curve of a certain type of unmanned surface vessel under this invention.

[0060] Figure 5 The graph shows the state tracking error variables of a certain type of unmanned surface vessel under the present invention.

[0061] Figure 6 The diagram shows the control force curve of a certain type of unmanned surface vessel under the present invention. Detailed implementation method:

[0062] To make the objectives, features, and advantages of the control method described in this invention more apparent and understandable, the invention will now be described in detail with reference to the accompanying drawings:

[0063] like Figure 1 A target tracking performance constraint control method for unmanned surface vessels based on an exponential time-varying performance function includes the following steps:

[0064] Step (1): Establish a three-degree-of-freedom mathematical model of the unmanned surface vessel's motion:

[0065] Based on the motion of the unmanned surface vessel (USV) on the water surface, a three-degree-of-freedom mathematical model of the USV is established in both a fixed coordinate system and a ship coordinate system, considering its pitch, sway, and bow angular velocities. This model includes a three-degree-of-freedom kinematic model and a three-degree-of-freedom dynamic model.

[0066] A three-degree-of-freedom model of an unmanned surface vessel in a fixed coordinate system:

[0067]

[0068] A three-degree-of-freedom model of an unmanned surface vessel in the ship's coordinate system:

[0069]

[0070] In the above formula, x, y, and ψ represent the northward, eastward, and bow angles of the unmanned surface vessel (USV) in a fixed coordinate system, respectively; u, v, and r represent the pitch velocity, sway velocity, and bow angular velocity of the USV, respectively; m 11 ,m 22 ,m 33 The mass m represents the inherent mass of the unmanned surface vessel. 23 ,m32 Represents the added mass of the unmanned surface vessel; Coriolis matrix and damping matrix, parameter C 13 =-C 31 =-m 22 vm 22 r, C 32 =-C 23 =m 11 u, D 11 D 22 D 23 D 32 and D 33 τ is the hydrodynamic damping parameter. u ,τ r These represent the sway controller and the heading controller, respectively.

[0071] Step (2): Construct an exponential time-varying function:

[0072] like Figure 3 As shown, κ(t) is the curve of an exponential time-varying function, and its specific functional expression is as follows:

[0073] Where n > 0 and T > 0 is the user-defined adjustment time;

[0074] Step (3): Construct the exponential time-varying performance function:

[0075] like Figure 3 As shown, γ(t) is the exponential time-varying performance function constructed in step (2), and its specific mathematical expression is as follows:

[0076] Where a > 0, t > 0, and ε → 0. γ(t) is a smooth decreasing function with the following properties:

[0077] 1) When t≥T, γ(t)=a and

[0078] 2) For t > 0, γ i (t)(i=1,2,...,n) is continuously differentiable.

[0079] Step (4): Introduce a time-varying auxiliary function:

[0080] like Figure 3 As shown, β(t) is the curve image of the time-varying auxiliary function introduced in step (2), and its specific form is: Where 0 < b << 1, β(t) satisfies the following condition:

[0081] 1) When t≥T, β(t)=1 / b and β(0)=1;

[0082] 2) For t > 0, β i (t)(i=1,2,...,n) is continuously differentiable;

[0083] 3) When t≥T, β n+1 (t) is continuous and bounded.

[0084] Therefore, the constructed auxiliary variable is: ζ l (t)=β(t)z l (t), where z l (t)=ll d Let l represent the original state error of the unmanned surface vessel and l∈{ψ,r,u}.

[0085] Step (5): Design the transformation function

[0086] A transformation function is designed to obtain a new state error system for the unmanned surface vessel (USV). Constraints are then applied to this new state error system. The specific form of the designed transformation function is as follows: Its first derivative can be expressed as: in They are represented as follows:

[0087]

[0088] Therefore, the state error systems of the unmanned surface vessel's pitch velocity, heading angle, and heading angular velocity in step (1) are transformed to obtain a new state error system s for the unmanned surface vessel. ψ ,s r ,s u The unmanned surface vessel system is unaffected by the initial error value z of the original state. l Under the constraint (0), the original state error satisfies the following constraint condition: -γ l (t) / β(t)<z l (t)<γ l (t) / β(t).

[0089] Step (6): Design a fixed-time performance-constrained forward controller based on an exponential time-varying performance function:

[0090] Based on the three-degree-of-freedom mathematical model of the unmanned surface vessel in step (1), a virtual control input r is designed. d And a fixed-time performance-constrained forward controller based on an exponential time-varying performance function.

[0091] Define the error variable:

[0092] z ψ =ψ-ψ d ;

[0093] z r =rrd ;

[0094] In the above formula, ψ d It is the desired heading angle of the unmanned surface vessel; z ψ It is the heading angle tracking error; z r It is the heading angular velocity tracking error; r d It is a virtual control input.

[0095] Substitute the above error variables into step (4) to construct the following dynamic auxiliary variables for the second-order heading dynamic error subsystem:

[0096] ζ ψ (t)=β(t)z ψ ;

[0097] ζ r (t)=β(t)z r ;

[0098] Substituting the above dynamic auxiliary variables into step (5) yields a new second-order bow dynamic error system for the unmanned surface vessel:

[0099]

[0100]

[0101] Furthermore, a fixed-time performance constraint heading controller for an unmanned surface vessel based on an exponential time-varying performance function is designed, which is carried out in the following two steps.

[0102] Step 1: Prove the convergence of the unmanned surface vessel's bow angle tracking error.

[0103] Consider the Lyapunov function:

[0104]

[0105] For V ψ Taking the first derivative, we get:

[0106]

[0107] To stabilize the bow angle tracking error of the unmanned surface vessel, a fixed-time virtual control input r is designed. d :

[0108]

[0109] In the above formula, 0 < λ1 < 1, λ2 > 1. and This represents the positive parameter to be designed.

[0110] Input virtual control r d Substitution From this, we can obtain:

[0111]

[0112] Step 2: Prove the convergence of the unmanned surface vessel's bow angular velocity tracking error.

[0113] Consider the Lyapunov function as follows:

[0114]

[0115] Taking the first derivative of the above equation:

[0116]

[0117] To stabilize the heading angular velocity tracking error of the unmanned surface vessel (USV), a fixed-time performance-constrained heading controller based on an exponential time-varying performance function is designed:

[0118]

[0119] In the above formula, All are represented as positive design parameters.

[0120] Fixed-time performance constraints on the unmanned surface vessel (USV) and its forward controller τ r Substitution From this, we can further obtain:

[0121]

[0122] In the above formula,

[0123] According to the fixed-time stability theory, the above equation shows that: error dynamics s ψ and s r Fixed-time convergence can be achieved. The fixed-time expression is:

[0124] Combining the above two design steps, the original state tracking error z can be obtained. ψ ,z r The new state tracking error s obtained after the transformation function ψ ,s r Global fixed-time convergence can be achieved. Thus, the stability performance analysis of the fixed-time performance-constrained forward controller based on the exponential time-varying performance function is completed.

[0125] Step (7): Design a fixed-time performance-constrained oscillation controller based on an exponential time-varying performance function:

[0126] Based on the three-degree-of-freedom mathematical model of the unmanned surface vessel in step (1), a fixed-time performance-constrained oscillation controller based on an exponential time-varying performance function is designed.

[0127] Define the error variable:

[0128] z u =uu d ;

[0129] In the above formula, u d This represents the expected pitch speed of the unmanned surface vessel.

[0130] Substituting the above error variables into step (4), the following dynamic auxiliary variables for sway velocity tracking error are constructed:

[0131] ζ u (t)=β(t)z u ;

[0132] Substituting the above dynamic auxiliary variables into step (5) yields a new system for tracking the unmanned surface vessel's sway velocity:

[0133]

[0134] Consider the Lyapunov function as follows:

[0135]

[0136] For V u Taking the first derivative, we get:

[0137]

[0138] To stabilize the tracking error of the unmanned surface vessel's sway velocity, a fixed-time performance-constrained sway controller based on an exponential time-varying performance function is designed:

[0139]

[0140] In the above formula, k u1 ,k u2 All of these are positive parameters to be designed.

[0141] Fixed-time performance constraint oscillation controller for unmanned surface vessels τ u Substitution Zhongde:

[0142]

[0143] In summary, the initial state tracking error z of the unmanned surface vessel can be obtained. u Global fixed-time convergence can be achieved through the transformation function. The fixed-time expression is as follows: This concludes the stability performance analysis of the fixed-time performance-constrained oscillation controller based on an exponential time-varying performance function.

[0144] Step (8): Simulation verification

[0145] Based on the fixed-time performance constraint directional controller and oscillation controller designed in steps (6) to (7) based on the exponential time-varying performance function; the simulation environment is set as follows: the target's position information is x L =50sin(0.02t), y L =t; The initial position information of the target is [0m, 0m]. The initial position information of the unmanned surface vessel is [-10m, -10m]. The initial bow angle of the unmanned surface vessel is π / 10rad, the initial bow angular velocity is 0rad / s, and the initial sway velocity is 0m / s.

[0146] This invention uses a certain type of underactuated unmanned surface vessel (USV) as the simulation object to conduct simulation verification of the target tracking control performance constraint method of USV based on an exponential time-varying performance function. Figure 3 The diagram shows specific images of the exponential time-varying function, the exponential time-varying performance function, and the variable auxiliary function designed in this invention. Figure 4 The diagram shows the expected curves of the bow angle, bow angular velocity, and sway velocity of the unmanned surface vessel, as well as the corresponding actual curves. It can be clearly seen from the diagram that the actual values ​​all converge to the expected values ​​within a fixed time T = 2s, reflecting that the constraint control method proposed in this invention has the advantages of shorter response time and faster response speed.

[0147] Figure 5 The graphs show the tracking errors for the initial pitch velocity, bow angle, and bow angular velocity of the unmanned surface vessel. It can be clearly observed from the graphs that the initial pitch velocity tracking error z... u It eventually converges within the steady-state range [-0.01 m / s, 0.01 m / s], and the original bow angle tracking error z ψ Finally, the tracking error converges within the steady-state range [-0.1 rad, 0.1 rad], and the original heading angular velocity tracking error finally converges within the steady-state range [-0.05 rad / s, 0.05 rad / ss]. Moreover, the original state tracking errors mentioned above converge rapidly within a fixed time T = 2 s, demonstrating that the present invention has better transient and steady-state performance, resulting in a smaller steady-state value of the state error. Figure 6 The bow control force curve and longitudinal control force curve of a certain type of underactuated unmanned surface vessel under the present invention are shown, indicating that the designed control law is relatively smooth and conforms to practical engineering applications.

[0148] This invention constrains the state tracking error of an unmanned surface vessel (USV) by designing an exponential time-varying performance function, and designs a fixed-time performance-constrained heading controller and sway controller for the USV. This solves the problem that the state error of traditional performance function-constrained control is limited by the performance boundary at the initial moment. The proposed control method can significantly improve the transient and steady-state performance of the USV's state tracking error, thereby improving the overall control performance of the USV.

[0149] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A target tracking constraint control method for unmanned surface vessels based on an exponential time-varying performance function, characterized in that: It includes the following steps: Step (1): Establish a three-degree-of-freedom mathematical model of the unmanned surface vessel's motion: Based on the motion of the unmanned surface vessel (USV) on the water surface, a three-degree-of-freedom mathematical model of the USV is established for its sway, roll, and bow motion in a fixed coordinate system and a ship coordinate system. This model includes a three-degree-of-freedom kinematic model and a three-degree-of-freedom dynamic model. Step (2): Construct an exponential time-varying function: To address the steady-state time of convergence of the state tracking error of the unmanned surface vessel, an exponential time-varying function is constructed. Step (3): Construct the exponential time-varying performance function: Based on the exponential time-varying function constructed in step (2), an exponential time-varying performance function is constructed to address the original state tracking error of the unmanned surface vessel. Step (4): Design a time-varying auxiliary function: Based on the exponential time-varying function constructed in step (2), a time-varying auxiliary function is designed to lay the groundwork for constructing a new state tracking error system for unmanned surface vessels. Step (5): Design the transformation function: Based on the exponential time-varying performance function and time-varying auxiliary function designed in steps (3) and (4), a transformation function is designed to obtain a new state error system for the unmanned surface vessel. Step (6): Design a fixed-time performance-constrained forward controller based on an exponential time-varying performance function: Based on the mathematical model established in step (1) and the transformed second-order heading dynamic error subsystem obtained in step (5), a fixed-time performance constraint heading controller based on an exponential time-varying performance function is designed using a backstepping recursive control method. Step (7): Design a fixed-time performance-constrained oscillation controller based on an exponential time-varying performance function: Based on the mathematical model established in step (1) and the transformed first-order sway dynamic error subsystem obtained in step (5), a fixed-time performance-constrained sway controller based on an exponential time-varying performance function is designed using the backstepping recursive control method. Step (8): Simulation verification: The fixed-time performance-constrained heading controller and sway controller based on the exponential time-varying performance function designed in steps (1) to (8) were simulated on an underactuated unmanned surface vessel.

2. The unmanned surface vessel target tracking control performance constraint method based on an exponential time-varying performance function according to claim 1, characterized in that: The establishment of the three-degree-of-freedom kinematic model of the hovercraft described in step (1) is as follows: Three-degree-of-freedom kinematic model of an unmanned surface vessel in a fixed coordinate system: Three-degree-of-freedom dynamic model of the unmanned surface vessel in the hull coordinate system: In the above formula, x, y, and ψ represent the northward, eastward, and bow angles of the unmanned surface vessel (USV) in a fixed coordinate system, respectively; u, v, and r represent the pitch velocity, sway velocity, and bow roll rate of the USV, respectively; m 11 ,m 22 ,m 33 The mass m represents the inherent mass of the unmanned surface vessel. 23 ,m 32 Represents the added mass of the unmanned surface vessel; Let C represent the Coriolis matrix and the damping matrix, respectively, with parameter C. 13 =-C 31 =-m 22 vm 22 r, C 32 =-C 23 =m 11 u, D 11 D 22 D 23 D 32 and D 33 τ is the hydrodynamic damping parameter. u ,τ r These represent the sway controller and the heading controller, respectively.

3. The unmanned surface vessel target tracking control performance constraint method based on an exponential time-varying performance function according to claim 1, characterized in that: The specific form of the exponential time-varying function mentioned in step (2) is as follows: Where n > 0 and T > 0 is the custom adjustment time.

4. The unmanned surface vessel target tracking control performance constraint method based on an exponential time-varying performance function according to claim 1, characterized in that: The specific form of the exponential time-varying performance function mentioned in step (3) is as follows: Where a > 0, t > 0 and ε → 0; The constructed exponential time-varying performance function γ(t) is a smoothly decreasing function with the following properties: 1) When t≥T, γ(t)=a and 2) For t > 0, γ i (t)(i=1,2,...,n) is continuously differentiable.

5. The unmanned surface vessel target tracking control performance constraint method based on an exponential time-varying performance function according to claim 1, characterized in that: The specific form of the time-varying auxiliary function mentioned in step (4) is as follows: Where 0 < b < < 1; The introduced time-varying auxiliary function has the following properties: 1) When t≥T, β(t)=1 / b and β(0)=1; 2) For t > 0, β i (t)(i=1,2,...,n) is continuously differentiable; 3) When t≥T, β n+1 (t) is continuous and bounded. Therefore, the constructed auxiliary variable is: ζ l (t)=β(t)z l (t), where z l (t)=ll d Let l represent the original state error of the unmanned surface vessel and l∈{u,ψ,r}.

6. The unmanned surface vessel target tracking control performance constraint method based on an exponential time-varying performance function according to claim 1, characterized in that: The specific form of the conversion function mentioned in step (5) is as follows: Taking the first derivative of the transformation function with respect to time, we obtain the specific form of its derivative: in They are represented as follows: Therefore, the unmanned surface vessel system is unaffected by the initial value z of the original state error. l Under the constraint (0), the original state error satisfies the following constraint condition: -γ l (t) / β(t)<z l (t)<γ l (t) / β(t).

7. The unmanned surface vessel target tracking performance constraint control method based on an exponential time-varying performance function according to claim 1, characterized in that: The design described in step (6) is a fixed-time performance-constrained forward controller based on an exponential time-varying performance function: Design virtual control input r d : In the above formula, For positive design parameters, 0 < λ1 < 1 and λ2 > 1 are all parameters to be designed. The first derivative of the desired heading angle of the unmanned surface vessel (USV); a fixed-time performance-constrained heading controller τ for USVs based on an exponential time-varying performance function. r : In the above formula, and All are positive design parameters, and 0 < λ1 < 1 and λ2 > 1 are design parameters.

8. The unmanned surface vessel target tracking performance constraint control method based on an exponential time-varying performance function according to claim 1, characterized in that: The design described in step (7) is a fixed-time performance-constrained oscillation controller based on an exponential time-varying performance function: Unmanned surface vessel (USV) fixed-time performance constraint oscillation controller τ based on exponential time-varying performance function u : In the above formula, The design parameters are positive, and 0 < λ1 < 1 and λ2 > 1 are the parameters to be designed.

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