An unmanned ship scheduled time trajectory tracking method based on asymmetric preset performance

Abstract

The application discloses an unmanned ship scheduled time trajectory tracking method based on asymmetric preset performance, which comprises the following steps: S1, a kinematics model and a dynamics model of a three-degree-of-freedom unmanned ship are established based on an Euler-Lagrange method, and the kinematics model and the dynamics model are expressed as a state equation of the unmanned ship system; S2, a system structure with scheduled time convergence characteristics is constructed, and stable convergence of the state of the unmanned ship system within scheduled time is realized; and S3, an asymmetric preset performance function is designed, trajectory tracking errors of the unmanned ship system are constrained, a dynamic evolution process of the errors is limited, and the errors are guaranteed to meet preset performance indexes. The application has the beneficial effects that a novel asymmetric preset performance function is constructed, the dynamic evolution process of system errors can be effectively constrained, the state errors of the system are always kept within preset performance boundaries, and therefore, the stability and control precision of the trajectory tracking process of the unmanned ship are improved.

Description

Technical Field

[0001] This invention relates to the technical field of unmanned vessel control, and specifically to a method for tracking the trajectory of an unmanned vessel at a predetermined time based on asymmetric preset performance. Background Technology

[0002] Unmanned surface vessels (USVs) are highly autonomous, intelligent, unmanned marine transport platforms characterized by maneuverability, cost-effectiveness, safety, reliability, and stealth. In recent years, they have received widespread attention in both military and civilian fields and have been gradually applied to various areas such as marine resource exploration, maritime search and rescue, intelligence gathering, security patrol, maritime cargo transportation, aquaculture, and water quality monitoring.

[0003] However, the motion control performance of unmanned surface vessels (USVs) is easily affected by various factors during mission execution. For example, USV dynamics systems exhibit significant nonlinearity and strong coupling characteristics, and are also affected by complex marine environmental disturbances such as wind, waves, and currents during actual operation. These factors often lead to trajectory deviations during USV navigation, thereby reducing the accuracy and efficiency of mission execution and even affecting the safety of system operation. As a typical nonlinear, strongly coupled control system, the motion control problem of USVs remains a complex and challenging research problem. Domestic and international scholars have conducted extensive research on the motion planning and trajectory tracking control of USVs and proposed various control methods. However, existing methods still suffer from slow convergence speed, insufficient control accuracy, and limited robustness in complex sea conditions. Furthermore, in real marine environments, USV systems are often affected by various unknown disturbances and model uncertainties. These uncertainties pose significant challenges to controller design, and existing control strategies typically suffer from slow convergence speed and poor control accuracy.

[0004] Therefore, there is an urgent need for an unmanned vessel trajectory tracking control method with strong robustness and high control accuracy, so that the unmanned vessel can achieve fast, stable and high-precision trajectory tracking control under complex marine environmental disturbances. However, there is a lack of relevant effective solutions in the existing technology. Summary of the Invention

[0005] Purpose of the invention: To provide a method for tracking the trajectory of an unmanned vessel at a predetermined time based on asymmetric preset performance, so as to solve the above-mentioned problems existing in the prior art.

[0006] Technical Solution: A method for tracking the trajectory of an unmanned surface vessel (USV) within a predetermined time based on asymmetric preset performance, comprising the following steps: S1, establishing a kinematic and dynamic model of a three-degree-of-freedom USV based on the Euler-Lagrange method, and expressing it as the state equation of the USV system; S2, constructing a system structure with predetermined time convergence characteristics to achieve stable convergence of the USV system state within a predetermined time; S3, designing an asymmetric preset performance function to constrain the trajectory tracking error of the USV system, limiting the dynamic evolution process of the error and ensuring that the error meets the preset performance indicators; S4, constructing a predetermined time sliding surface based on the predetermined time stability theory in S2 and the preset performance function in S3; S5, constructing a predetermined time preset performance trajectory tracking controller for the USV system based on the predetermined time sliding surface in S4, to achieve high-precision trajectory tracking control of the USV system.

[0007] Preferably, S1 specifically includes: S11. Establish the kinematics and dynamics equations of a three-degree-of-freedom unmanned surface vessel based on the Euler-Lagrange method: , in, The state of the unmanned surface vessel system in the inertial coordinate system. This represents the velocity state vector of the unmanned surface vessel in the ship's coordinate system. This is the transformation matrix between the inertial coordinate system and the ship's coordinate system. M ∈ R 3×3 Let be the system's inertia matrix. C ( v )∈ R 3×3 Denotes the Coriolis and centripetal force matrices of the system, D( v )∈ R 3×3 Here is the system damping matrix. This indicates the system control input, including longitudinal thrust. Lateral thrust and steering torque , d ext ∈ R 3×3 Indicates external disturbance; S12. Establish the uncertainties in the dynamic parameters of the unmanned vessel system: , in, , and These are the nominal inertia matrix, nominal Coriolis force matrix, centripetal force matrix, and nominal damping matrix of the unmanned surface vessel system, respectively. , and This indicates fluctuations in system parameters caused by perturbations in system dynamic parameters; S13. Derive the dynamic equations of the unmanned vessel considering the uncertainties of system dynamic parameters and external disturbances: , in, The system represents the lumped disturbance; the system matrices are expressed as follows: , , , , in, , , , , , , , , S14. Constructing the state-space equations for the unmanned surface vessel system .

[0008] Preferably, the system structure with predetermined time convergence characteristics in S2 specifically includes: , in, T Represents the predetermined time constant of the system. Represents about variables V intermediate function, The initial value satisfies .

[0009] Preferably, the transformation error of the preset performance function in S3 specifically includes: S31. Design an asymmetric preset performance function: , , in, Determine the performance function The convergence speed, For a very small positive real number, T Indicates the predetermined time constant. For function The final value, Represents performance function The final value; S32. Determine the state error of the unmanned surface vessel system. as follows: , in, This represents the desired trajectory of the unmanned vessel. This indicates the desired heading angle of the unmanned vessel; S33. Define the state error after transformation. : , in, Indicates state error , and The initial value of .

[0010] Preferably, the construction of the predetermined time sliding surface in S4 specifically includes: , in, Indicates the predetermined time constant. intermediate function The initial value; S is the sliding surface at a predetermined time, and .

[0011] Preferably, the unmanned vessel system pre-set performance trajectory tracking controller in S5 specifically includes: , , , in, Let be a positive real number. , intermediate function The initial value.

[0012] A control system for tracking the trajectory of an unmanned surface vessel at a predetermined time based on asymmetric constraint preset performance includes, The model building module is used to establish the kinematic and dynamic model of a three-degree-of-freedom unmanned vessel based on the Euler-Lagrange method and transform it into the state-space equation of the unmanned vessel system. The pre-defined time convergence system construction module is used to construct a system structure with pre-defined time convergence characteristics to ensure that the system state achieves stable convergence within a predetermined time. The asymmetric preset performance function construction module is used to design asymmetric preset performance functions to constrain the dynamic evolution process of trajectory tracking error of unmanned vessel system and ensure that the error meets the preset performance requirements. The pre-defined time sliding surface construction module is used to construct a sliding surface with pre-defined time convergence characteristics; The trajectory tracking controller module is used to combine the predetermined time stability theory and the preset performance control method to build a predetermined time preset performance trajectory tracking controller for unmanned vessels, so as to realize high-precision trajectory tracking control of the unmanned vessel system.

[0013] A computer device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the steps of any of the methods described above.

[0014] A computer-storable medium having a computer program stored thereon, characterized in that: when the computer program is executed by a processor, it implements the steps of any one of the methods described above.

[0015] The beneficial effects of this invention are: This invention constructs a novel asymmetric preset performance function that can effectively constrain the dynamic evolution of system errors, keeping the system state error within the preset performance boundary, thereby improving the stability and control accuracy of the unmanned vessel trajectory tracking process.

[0016] The asymmetric preset performance function proposed in this invention effectively avoids the limitations imposed by traditional preset performance control methods on the initial error of the system, enabling the control method to still work normally when the initial error of the system is unknown or large, thereby improving the applicability and engineering practicality of the control method.

[0017] This invention proposes a new type of predetermined time convergence criterion. Compared with existing predetermined time control methods, the controller designed in this invention significantly reduces the dependence on control parameters while ensuring system convergence performance, and the control system structure is simpler, thereby reducing the complexity of controller design. Attached Figure Description

[0018] Figure 1 This is a flowchart of the steps of the present invention; Figure 2 This is a schematic diagram of the planar motion coordinate system of the unmanned vessel in an embodiment of the present invention; Figure 3 This is a state tracking curve of the unmanned vessel system under lumped disturbances in an embodiment of the present invention; Figure 4 This is a speed tracking curve of the unmanned vessel system under lumped disturbance in an embodiment of the present invention; Figure 5 This is an example of an unmanned surface vessel (USV) system under lumped disturbances in an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] As attached Figure 1-5 As shown in this embodiment, a method for tracking the trajectory of an unmanned surface vessel at a predetermined time based on asymmetric preset performance includes the following steps: S1. Establish the kinematic and dynamic models of the three-degree-of-freedom unmanned vessel based on the Euler-Lagrange method, and express them as the state equations of the unmanned vessel system. S11. Establish the kinematics and dynamics equations of a three-degree-of-freedom unmanned surface vessel based on the Euler-Lagrange method: , in, The state of the unmanned surface vessel system in the inertial coordinate system. This represents the velocity state vector of the unmanned surface vessel in the ship's coordinate system. This is the transformation matrix between the inertial coordinate system and the ship's coordinate system. M ∈ R 3×3 Let be the system's inertia matrix. C ( v )∈ R 3×3 Denotes the Coriolis and centripetal force matrices of the system, D( v )∈ R 3×3 Here is the system damping matrix. This indicates the system control input, including longitudinal thrust. Lateral thrust and steering torque , d ext ∈ R 3×3 This indicates an external disturbance. Among them, x This represents the longitudinal position of the unmanned vessel. y This represents the lateral position of the unmanned vessel. φ The bow angle of the unmanned vessel. u , v , r These are the longitudinal speed, lateral speed, and angular velocity of the unmanned surface vessel. for The first derivative, for The first derivative.

[0021] S12. Establish the uncertainties in the dynamic parameters of the unmanned vessel system: , in, M 0、 C 0( v )and D 0( v These represent the nominal inertia matrix, nominal Coriolis and centripetal force matrix, and nominal damping matrix of the unmanned surface vessel system, respectively. M Δ , C Δ and D Δ This indicates fluctuations in system parameters caused by perturbations in system dynamic parameters.

[0022] S13. Derive the dynamic equations of the unmanned vessel considering the uncertainties of system dynamic parameters and external disturbances: , in, The system represents the lumped disturbance; the system matrices are expressed as follows: , , , , in, , , , , , , , .

[0023] In this embodiment, the specific parameters of the unmanned surface vessel system are as follows: , S14. Construct the state-space equations for the unmanned vessel system. η Perform first and second derivatives: .

[0024] In this embodiment, the lumped disturbance of the unmanned surface vessel system is set as follows: .

[0025] S2. Construct a system structure with convergence characteristics within a predetermined time to achieve stable convergence of the unmanned vessel system state within a predetermined time; specifically including: , in,T Represents the predetermined time constant of the system. Represents about variables V intermediate function, The initial value satisfies .in, for V The first derivative.

[0026] In this embodiment, the predetermined time constant is set as follows: .

[0027] S3. Design an asymmetric preset performance function to constrain the trajectory tracking error of the unmanned surface vessel system, limit the dynamic evolution of the error, and ensure that the error meets the preset performance indicators; specifically including: S31. Design an asymmetric preset performance function: , , in, Determine the performance function The convergence speed, For a very small positive real number, T Indicates the predetermined time constant. For function The final value, Represents performance function The final value; In this embodiment, the preset performance function parameters are set as follows: , , , .

[0028] S32. Determine the state error of the unmanned surface vessel system. as follows: , in, This represents the desired trajectory of the unmanned vessel. This indicates the desired heading angle of the unmanned vessel; The desired state for the unmanned surface vessel system. e x ( t The ) indicates the error in the longitudinal position of the unmanned surface vessel. e y ( t The ) indicates the error in the lateral position of the unmanned vessel. This represents the error in the bow angle of the unmanned vessel.

[0029] In this embodiment, the initial state of the unmanned vessel is as follows: , The system's expected trajectory is .

[0030] S33. Define the state error after transformation. as follows: , in, Indicates state error , and The initial value of .

[0031] S4. Based on the predetermined time stability theory in S2 and the preset performance function in S3, construct the predetermined time sliding surface; The construction of the predetermined time sliding surface in S4 specifically includes: , in, Indicates the predetermined time constant. intermediate function The initial value; S is the sliding surface at a predetermined time, and .

[0032] In this embodiment, the predetermined time constant is set as follows: .

[0033] S5. Based on the predetermined time sliding surface in S4, construct a predetermined time preset performance trajectory tracking controller for the unmanned surface vessel system to achieve high-precision trajectory tracking control of the unmanned surface vessel system. Specifically, this includes: , , , in, Let be a positive real number. , This is the initial value of the intermediate function. This is an equivalent control law. To switch control laws, This is a sliding mode control law.

[0034] In this embodiment, the parameters of the predetermined time controller are set as follows: , .

[0035] A control system for tracking the trajectory of an unmanned surface vessel at a predetermined time based on asymmetric constraint preset performance includes, The model building module is used to establish the kinematic and dynamic model of a three-degree-of-freedom unmanned vessel based on the Euler-Lagrange method and transform it into the state-space equation of the unmanned vessel system. The pre-defined time convergence system construction module is used to construct a system structure with pre-defined time convergence characteristics to ensure that the system state achieves stable convergence within a predetermined time. The asymmetric preset performance function construction module is used to design asymmetric preset performance functions to constrain the dynamic evolution process of trajectory tracking error of unmanned vessel system and ensure that the error meets the preset performance requirements. The pre-defined time sliding surface construction module is used to construct a sliding surface with pre-defined time convergence characteristics; The trajectory tracking controller module is used to combine the predetermined time stability theory and the preset performance control method to build a predetermined time preset performance trajectory tracking controller for unmanned vessels, so as to realize high-precision trajectory tracking control of the unmanned vessel system.

[0036] A computer device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the steps of any of the methods described above.

[0037] A computer-storable medium having a computer program stored thereon, characterized in that: when the computer program is executed by a processor, it implements the steps of any one of the methods described above.

[0038] The simulation results obtained based on MATLAB are as follows: Figures 3-5 As shown.

[0039] Specifically, from Figure 3 It can be seen that even when the unmanned surface vessel (USV) system is affected by external environmental disturbances and model uncertainties, the designed controller can still enable the USV to reach the desired trajectory in about 7 seconds in terms of position and heading angle. Therefore, the proposed controller has a certain degree of robustness to external environmental disturbances.

[0040] Depend on Figure 4 It can be seen that the longitudinal speed, lateral speed and turning angular velocity of the unmanned vessel can reach the desired speed in about 7 seconds. Therefore, the proposed controller has better dynamic performance for unmanned vessel speed tracking.

[0041] exist Figure 5 In this study, the tracking error of the unmanned surface vessel can converge to within the preset performance function curve within a predetermined time and remain within the preset performance function curve. Therefore, the proposed control method can meet the preset performance constraints.

[0042] Simulation results show that the control method designed in this invention can achieve fast and accurate trajectory tracking control of unmanned vessels under external disturbances and model uncertainties.

[0043] The preferred embodiments have been shown and described, but should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for tracking the trajectory of an unmanned surface vessel at a predetermined time based on asymmetric preset performance, characterized in that: Includes the following steps: S1. Establish the kinematic and dynamic models of the three-degree-of-freedom unmanned vessel based on the Euler-Lagrange method, and express them as the state equations of the unmanned vessel system. S2. Construct a system structure with convergence characteristics within a predetermined time to achieve stable convergence of the unmanned vessel system state within a predetermined time. S3. Design an asymmetric preset performance function to constrain the trajectory tracking error of the unmanned vessel system, limit the dynamic evolution process of the error and ensure that the error meets the preset performance indicators. S4. Based on the predetermined time stability theory in S2 and the preset performance function in S3, construct the predetermined time sliding surface; S5. Based on the predetermined time sliding surface in S4, construct a predetermined time preset performance trajectory tracking controller for the unmanned vessel system to achieve high-precision trajectory tracking control of the unmanned vessel system.

2. The method for tracking the trajectory of an unmanned surface vessel at a predetermined time based on asymmetric preset performance according to claim 1, characterized in that: S1 specifically includes: S11. Establish the kinematics and dynamics equations of a three-degree-of-freedom unmanned surface vessel based on the Euler-Lagrange method: ， in, The state of the unmanned surface vessel system in the inertial coordinate system. This represents the velocity state vector of the unmanned surface vessel in the ship's coordinate system. This is the transformation matrix between the inertial coordinate system and the ship's coordinate system. M ∈ R 3×3 Let be the system's inertia matrix. C ( v )∈ R 3×3 Denotes the Coriolis and centripetal force matrices of the system, D( v )∈ R 3×3 Here is the system damping matrix. This indicates the system control input, including longitudinal thrust. Lateral thrust and steering torque , d ext ∈ R 3×3 Indicates external disturbance; S12. Establish the uncertainties in the dynamic parameters of the unmanned vessel system: ， in, M 0、 C 0( v )and D 0( v These represent the nominal inertia matrix, nominal Coriolis and centripetal force matrix, and nominal damping matrix of the unmanned surface vessel system, respectively. M Δ , C Δ and D Δ This indicates fluctuations in system parameters caused by perturbations in system dynamic parameters; S13. Derive the dynamic equations of the unmanned vessel considering the uncertainties of system dynamic parameters and external disturbances: ， in, The system represents the lumped disturbance; the system matrices are expressed as follows: ， ， , , in, , , , , , , , , S14. Constructing the state-space equations for the unmanned surface vessel system 。 3. The method for tracking the trajectory of an unmanned surface vessel at a predetermined time based on asymmetric preset performance according to claim 2, characterized in that: The system structure with predetermined time convergence characteristics in S2 specifically includes: ， in, T Represents the predetermined time constant of the system. Represents about variables V intermediate function, The initial value satisfies .

4. The method for tracking the trajectory of an unmanned surface vessel at a predetermined time based on asymmetric preset performance according to claim 3, characterized in that: The transformation error of the preset performance function in S3 specifically includes: S31. Design an asymmetric preset performance function: ， ， in, Determine the performance function The convergence speed, For a very small positive real number, T Indicates the predetermined time constant. For function The final value, Represents performance function The final value; S32. Determine the state error of the unmanned surface vessel system. as follows: ， in, This represents the desired trajectory of the unmanned vessel. This indicates the desired heading angle of the unmanned vessel; S33. Define the state error after transformation. : ， in, Indicates state error , and The initial value of .

5. The method for tracking the trajectory of an unmanned surface vessel at a predetermined time based on asymmetric preset performance according to claim 4, characterized in that: The construction of the predetermined time sliding surface in S4 specifically includes: ， in, Indicates the predetermined time constant. intermediate function The initial value; S is the sliding surface at a predetermined time, and .

6. The method for tracking the trajectory of an unmanned surface vessel at a predetermined time based on asymmetric preset performance according to claim 5, characterized in that: The unmanned vessel system's pre-set performance trajectory tracking controller in S5 specifically includes: ， ， in, Let be a positive real number. , intermediate function The initial value.

7. A control system for tracking the trajectory of an unmanned surface vessel at a predetermined time based on asymmetric constraint preset performance, characterized in that: include, The model building module is used to establish the kinematic and dynamic model of a three-degree-of-freedom unmanned vessel based on the Euler-Lagrange method and transform it into the state-space equation of the unmanned vessel system. The pre-defined time convergence system construction module is used to construct a system structure with pre-defined time convergence characteristics to ensure that the system state achieves stable convergence within a predetermined time. The asymmetric preset performance function construction module is used to design asymmetric preset performance functions to constrain the dynamic evolution process of trajectory tracking error of unmanned vessel system and ensure that the error meets the preset performance requirements. The pre-defined time sliding surface construction module is used to construct a sliding surface with pre-defined time convergence characteristics; The trajectory tracking controller module is used to combine the predetermined time stability theory and the preset performance control method to build a predetermined time preset performance trajectory tracking controller for unmanned vessels, so as to realize high-precision trajectory tracking control of the unmanned vessel system.

8. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor, when executing the computer program, implements the steps of the method according to any one of claims 1-6.

9. A computer-storable medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1-6.

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