Unmanned ship control method based on fixed-time extended state observer

Abstract

The application relates to a kind of unmanned ship control method based on fixed time expansion state observer, comprising the following steps: step S1: the state information of unmanned ship and the information data of various sensors are acquired, and are sent to control center;Step S2, the information data is classified and matched according to data type, and the corresponding state information of unmanned ship is obtained;Step S3: fixed time expansion state observer is constructed, disturbance and uncertainty term are accurately estimated and controller is compensated, and the estimation value of the auxiliary speed variable of unmanned ship is obtained;Step S4: the desired trajectory is specified, and the actual position in the state information is subtracted to obtain the position error;Step S5: the desired control input of unmanned ship is obtained through the controller;Step S6: the control input is packaged and checked, and is sent to the main control of unmanned ship;Step S7: the main control controls unmanned ship to execute control command, and completes the trajectory tracking task.The application realizes that unmanned ship accurately and stably tracks desired trajectory.

Description

Technical Field

[0001] This invention belongs to the field of unmanned vessel trajectory tracking and control technology, specifically relating to an unmanned vessel control method based on a fixed-time extended state observer. Background Technology

[0002] With rapid economic and social development, people's demand for marine resources is increasing daily. Simultaneously, advancements in science and technology have provided more means for exploring and utilizing marine resources. Among numerous marine applications, unmanned surface vessels (USVs) play a crucial role, primarily due to their high maneuverability, low cost, autonomous navigation, modularity, and stealth capabilities. They can perform functions such as reconnaissance and surveillance, rescue and search, and intelligence gathering. The core foundation for these functions is the motion control of USVs, with trajectory tracking control remaining a hot topic. However, due to the inherent characteristics of USVs and the complexity and unpredictability of actual sea conditions, controlling them faces a series of challenges. Unlike unmanned vehicles and drones, USVs navigate on the sea surface, making them highly susceptible to environmental disturbances such as wind, waves, and currents, which can lead to equipment malfunctions or even instability in the motion system. Therefore, how to resist external interference is a crucial consideration when designing motion control algorithms for USVs. Consequently, the trajectory tracking control problem of USVs has received significant attention from researchers in the fields of marine engineering and control engineering. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide an unmanned vessel control method based on a fixed-time extended state observer, which aims to solve the above-mentioned problems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for controlling unmanned vessels based on a fixed-time extended state observer includes the following steps:

[0006] Step S1: Acquire the status information of the unmanned vessel and the information data from various sensors, and send them to the control center;

[0007] Step S2: The control center classifies and matches the information data according to the data type to obtain the corresponding status information of the unmanned vessel.

[0008] Step S3: Based on disturbances, unmodeled dynamics, actuator failures, and unknown speeds in the marine environment, a fixed-time extended state observer is constructed to accurately estimate disturbances and uncertainties and compensate the controller, while obtaining the estimated values ​​of the unmanned vessel's auxiliary speed variables.

[0009] Step S4: Specify the desired trajectory and subtract it from the actual position in the status information to obtain the position error;

[0010] Step S5: Send the speed and total disturbance estimates, position error and desired trajectory to the fixed-time trajectory output feedback to the controller, and obtain the desired control input of the unmanned vessel through the controller;

[0011] Step S6: Package and verify the control inputs, and send them to the main control unit of the unmanned vessel;

[0012] Step S7: The main control unit executes control commands to complete the trajectory tracking task.

[0013] Furthermore, the communication between the unmanned vessel and the control center is based on the TCP / IP protocol; the unmanned vessel's main controller establishes a TCP server, which can establish connections with one or more TCP clients and read and write data; while the control center needs to have a TCP client to establish a connection with the unmanned vessel's main controller.

[0014] Furthermore, after obtaining the unmanned vessel's status information, the control center verifies the data returned by the unmanned vessel. The verification standard is to determine whether the returned data conforms to CRC16. If the verification fails, it means that the returned data is incorrect and the request needs to be resent. The returned new data needs to be verified again.

[0015] Furthermore, step S3 specifically includes:

[0016] Step S31: Construct a mathematical model of the unmanned vessel;

[0017] Step S32: Based on the mathematical model of the unmanned vessel, considering disturbances in the marine environment, unmodeled dynamics, actuator failures, and unknown speeds, construct a fixed-time extended state observer.

[0018] Furthermore, the construction of the mathematical model for the unmanned vessel is as follows:

[0019] The motion control problem of unmanned surface vessels (USVs) typically considers the USV's planar motion and utilizes an inertial coordinate system (O). n x n y n ) and attached coordinate system (O b x b y b Establish a mathematical model for the unmanned surface vessel;

[0020] Based on the motion characteristics of the fully driven unmanned vessel system, dynamic and kinematic equations are established, and its three-degree-of-freedom model expression is as follows:

[0021]

[0022]

[0023] in, Let be the position vector of the unmanned vessel in the inertial coordinate system, (x, y) be the actual position of the unmanned vessel, and ψ be the heading angle of the unmanned vessel. Let u be the velocity vector of the unmanned vessel in the attached coordinate system, where u is the forward velocity, v is the lateral drift velocity, and r is the bow roll angular velocity. The control vector is the input for the ship's propulsion control, where τ1 is the forward force, τ2 is the lateral drift force, and τ3 is the bow roll torque. For unmanned vessels in the attached coordinate system, external disturbances caused by wind, waves, etc. are considered. d1 is the lateral disturbance force, d2 is the longitudinal disturbance force, and d3 is the bow disturbance moment. Let M be the mismatch disturbance caused by ocean currents; J(ψ) be the matrix composed of the unmanned vessel's weight inertia and hydrodynamically added inertia; C(v) be the coordinate system transformation matrix; D(v) be the Coriolis-centripetal matrix; and D(v) be the hydrodynamic damping parameter matrix. The expressions for M, J(ψ), C(v), and D(v) are as follows:

[0024]

[0025]

[0026]

[0027]

[0028] in, d 11 (u)=-X u -X |u|u |u|,d 22 (v, r) = -Y v -Y |v|v |v|-Y |r|v |r|,d 23 (v, r) = -Y r -Y |v|r |v|-Y |r|r |r|,d 32 (v, r) = -N v -N |v|v |v|-N |r|v |r|,d 33 (v, r) = -N r -N |v|r |v|-N |r|r|r|. m is the mass of the unmanned vessel, I z Let x be the moment of inertia. g X(·), Y(·), and N(·) are the distances between the center of gravity of the unmanned vessel and the origin of the attached coordinate system, and X(·), Y(·), and N(·) are the hydrodynamic derivatives of the system.

[0029] The transformation matrix J(ψ) has the following properties

[0030] J(ψ) T J(ψ)=I (7)

[0031]

[0032] J(ψ) T R(r)J(ψ)=R(r) (9)

[0033] Where R(r) is defined as

[0034]

[0035] Since the Coriolis-centripetal matrix C(v), the hydrodynamic damping parameter matrix D(v), and the velocity vector v are all unknown; furthermore, considering the impact of actuator failure on the unmanned vessel control system, the control torque affected by actuator failure is expressed as...

[0036]

[0037] Where τ i (i = 1, 2, 3) represents the actual control input to the ship's propulsion system; τ ni For the desired control input of the design; e ii is the health status index of the i-th actuator, which ranges from 0 to 1; For unknown error input; b i (tt 0i () is a time index.

[0038] Furthermore, the time index specifically refers to...

[0039]

[0040] In equation (12), a i The degree of failure of the actuator as a function of time, t 0i This indicates the time when the fault occurred. If the actuator experiences a serious fault, i.e., a i If the value is large, then b i (tt 0i It takes the form of a step function; similarly, when a i When the value is small, the actuator will slowly fail, which is called a slow-change failure.

[0041] Furthermore, the fixed-time extended state observer is constructed as follows:

[0042] Introduce an auxiliary velocity variable w, and define it as follows:

[0043] w=J(ψ)v+v r (13)

[0044] Then, equation (1) is transformed into

[0045]

[0046]

[0047]

[0048] Where χ represents the sum of unknown disturbances. This represents the desired trajectory. For the desired control input of the design;

[0049] Then, position error and velocity error are defined.

[0050] η e =η-η d (17)

[0051] w e =ww d (18)

[0052] in, The desired velocity vector;

[0053] The next step is to differentiate equations (17) and (18):

[0054]

[0055]

[0056] The design of the observer can effectively estimate the unknown velocity and the sum of all observed uncertainties. The process is as follows:

[0057]

[0058] in Let η be the estimated position of the unmanned surface vessel. The estimated value of the unmanned surface vessel's assisted speed w. Let χ be an estimated value, where χ is the sum of the uncertainties of the unmanned vessel, and its expression is:

[0059] χ=Γ+Δ+E+Z (22)

[0060] Where Γ represents the mismatch disturbance caused by ocean currents.

[0061]

[0062] Δ represents the matching disturbance caused by wind and waves in the marine environment.

[0063] Δ=J(ψ)M -1 d (24)

[0064] E represents the uncertainty term in the unmodeled part of the unmanned vessel dynamics.

[0065] E=J(ψ)R(r)vJ(ψ)M -1 C(v)-J(ψ)M -1 D(v) (25)

[0066] Z represents the uncertainty term caused by execution failure.

[0067]

[0068] Where, B(t-t0)=diag(b(tt) 01 ), b(tt 02 ), b(tt 03 E = diag(e) 11 e 22 e 33 ), τ n =[τ n1 , τ n2 , τ n3 ] T ,

[0069] By selecting appropriate parameters, the fixed-time extended state observer is uniformly fixed-time stable.

[0070] Given that the speed of the unmanned vessel is unknown, and considering the uncertainties of unmodeled dynamics, unknown disturbances, and actuator failures, an auxiliary speed estimate is needed using a fixed-time extended state observer. The sum of estimates of the uncertainty terms Feedback is then incorporated into the subsequent controller design to achieve stable operation of the unmanned vessel; ultimately, the control law is designed as follows:

[0071]

[0072] Where K η =diag(K) η1 K η2 K η3 ), K w =diag(K) w1K w2 K w3 All of these are control gain matrices, and α1∈(0,1); while The auxiliary velocity estimation error is defined as follows:

[0073] Furthermore, the appropriate parameter selection is as follows:

[0074] (1) λ3=1.1L w .

[0075] (2) δ>0 should be chosen to be sufficiently small, and at the same time The Herwitz matrix should be chosen, as follows:

[0076]

[0077] (3) Where T u It is a positive number.

[0078] Compared with the prior art, the present invention has the following advantages:

[0079] This invention estimates and compensates for these unknowns by designing an extended state observer, and introduces a fixed-time control method to improve the performance of the control system, enabling the unmanned vessel to accurately and stably track the desired trajectory. Attached Figure Description

[0080] Figure 1 This describes the motion of an unmanned surface vessel in an inertial coordinate system and an attached coordinate system in one embodiment of the present invention.

[0081] Figure 2 This is a flowchart of a method according to an embodiment of the present invention;

[0082] Figure 3 This is an example of the circular trajectory tracking effect of an unmanned surface vessel in an inertial coordinate system in one embodiment of the present invention.

[0083] Figure 4 This refers to the positional error of the circular trajectory in one embodiment of the present invention.

[0084] Figure 5 This refers to the actual tracking speed of the unmanned vessel in one embodiment of the present invention.

[0085] Figure 6 This is the actual control input for the circular trajectory in one embodiment of the present invention;

[0086] Figure 7 In one embodiment of the present invention, χ represents the total uncertainty term in the system and its observed values, where χ is the sum of the actual uncertainties of the unmanned vessel. Its observed value;

[0087] Figure 8 These are the actual and observed values ​​of the unmanned surface vessel's auxiliary speed variable in one embodiment of the present invention, where w is the actual value. These are the observed values;

[0088] Figure 9 This is a flowchart illustrating the practical application of the unmanned vessel algorithm in one embodiment of the present invention. Detailed Implementation

[0089] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0090] Please refer to Figure 2 This invention provides a method for controlling unmanned vessels based on a fixed-time extended state observer:

[0091] Step 1: Send a command to request communication and request various status information of the unmanned vessel;

[0092] Step 2: The main controller collects information from various sensors, verifies it, and packages it according to the specified format.

[0093] Step 3: The packaged file is sent to the control center via TCP / IP protocol;

[0094] Step 4: The control center receives the file, verifies and unpacks the file according to the format, and then classifies and matches the data according to the data type to obtain the corresponding status information of the unmanned vessel.

[0095] Step 5: In response to the problems of disturbances, unmodeled dynamics, actuator failures and unknown speeds in the marine environment, a fixed-time extended state observer is constructed to accurately estimate the disturbances and uncertainties and compensate the controller, while obtaining the estimated value of the unmanned vessel's auxiliary speed variable.

[0096] Step 6: Specify the desired trajectory and subtract it from the actual position in the status information to obtain the position error;

[0097] Step 7: The next step is to send the speed and total disturbance estimates, position error and desired trajectory to the fixed-time trajectory output feedback controller, and obtain the desired control input of the unmanned vessel through the algorithm.

[0098] Step 8: According to the communication protocol, the prepared data packet is sent to the unmanned surface vessel's (USV) main controller. The USV main controller then processes the data according to the verification, unpacking, and matching process to obtain the desired control input, and sends it to the underlying controller.

[0099] Step 9: The underlying controller adjusts the duty cycle through PWM waves to control the actuators of the unmanned vessel, thereby achieving the desired control input and realizing the purpose of trajectory tracking.

[0100] In this embodiment, communication between the unmanned surface vessel (USV) and the control center is based on the TCP / IP protocol. Therefore, the USV's main controller needs to establish a TCP server capable of connecting to one or more TCP clients and reading and writing data. The control center, on the other hand, needs to establish a TCP client to connect to the controller.

[0101] In this embodiment, the control center sends a request command to obtain the unmanned surface vessel's (USV) status information. After obtaining the USV status information, the data returned by the USV is verified. The verification standard is to determine whether the returned data conforms to CRC16. If the verification fails, it indicates that the returned data is incorrect, and the request needs to be resent. The returned data needs to be verified again. Simultaneously, the returned data needs to be unpacked. Since TCP / IP can only send and receive uint8_t data, the returned data needs to be unpacked to restore it to types such as double, float, and int. The unpacking and packing procedures are based on IEEE 754. Subsequently, the unpacked data is matched to obtain the USV's latitude and longitude information, and a conversion tool is used to convert the latitude and longitude to UTM coordinates (Universal Transverse Mercator).

[0102] In this embodiment, the mathematical model of the unmanned vessel is constructed as follows:

[0103] The motion control problem of unmanned surface vessels (USVs) typically considers the USV's planar motion and utilizes an inertial coordinate system (O). n x n y n ) and attached coordinate system (O b x b y b Establish a mathematical model for the unmanned surface vessel;

[0104] Based on the motion characteristics of the fully driven unmanned vessel system, dynamic and kinematic equations are established, and its three-degree-of-freedom model expression is as follows:

[0105]

[0106]

[0107] in, Let be the position vector of the unmanned vessel in the inertial coordinate system, (x, y) be the actual position of the unmanned vessel, and ψ be the heading angle of the unmanned vessel. Let u be the velocity vector of the unmanned vessel in the attached coordinate system, where u is the forward velocity, v is the lateral drift velocity, and r is the bow roll angular velocity. The control vector is the input for the ship's propulsion control, where τ1 is the forward force, τ2 is the lateral drift force, and τ3 is the bow roll torque. For unmanned vessels in the attached coordinate system, external disturbances caused by wind, waves, etc. are considered. d1 is the lateral disturbance force, d2 is the longitudinal disturbance force, and d3 is the bow disturbance moment. Let M be the mismatch disturbance caused by ocean currents; J(ψ) be the matrix composed of the unmanned vessel's weight inertia and hydrodynamically added inertia; C(v) be the coordinate system transformation matrix; D(v) be the Coriolis-centripetal matrix; and D(v) be the hydrodynamic damping parameter matrix. The expressions for M, J(ψ), C(v), and D(v) are as follows:

[0108]

[0109]

[0110]

[0111]

[0112] in, d 11 (u)=-X u -X |u|u |u|,d 22 (v, r) = -Y v -Y |v|v |v|-Y |r|v |r|,d 23 (v, r) = -Y r -Y |v|r |v|-Y |r|r |r|,d 32 (v, r) = -N v -N |v|v |v|-N |r|v |r|,d 33 (v, r) = -N r -N |v|r |v|-N |r|r |r|. m is the mass of the unmanned vessel, I z Let x be the moment of inertia. g X(·), Y(·), and N(·) are the distances between the center of gravity of the unmanned vessel and the origin of the attached coordinate system, and X(·), Y(·), and N(·) are the hydrodynamic derivatives of the system.

[0113] In this embodiment, the specific parameters are shown in Table 2.

[0114] Table 2 Detailed parameters of unmanned surface vessels

[0115]

[0116]

[0117] The transformation matrix J(ψ) has the following properties

[0118] J(ψ) T J(ψ)=I (7)

[0119]

[0120] J(ψ) T R(r)J(ψ)=R(r) (9)

[0121] Where R(r) is defined as

[0122]

[0123] Since the Coriolis-centripetal matrix C(v), the hydrodynamic damping parameter matrix D(v), and the velocity vector v are all unknown; furthermore, considering the impact of actuator failure on the unmanned vessel control system, the control torque affected by actuator failure is expressed as...

[0124]

[0125] Where τ i (i = 1, 2, 3) represents the actual control input to the ship's propulsion system; τ ni For the desired control input of the design; e ii Let be the health status index of the i-th actuator, which ranges from 0 to 1; For unknown error input; b i (tt 0i () is a time index.

[0126] In this embodiment, the time index is specifically...

[0127]

[0128] In equation (12), a i The degree of failure of the actuator as a function of time, t 0i This indicates the time when the fault occurred. If the actuator experiences a serious fault, i.e., a i If the value is large, then b i (tt 0i It takes the form of a step function; similarly, when a i When the value is small, the actuator will slowly fail, which is called a slow-change failure.

[0129] In this embodiment, the fixed-time extended state observer is constructed as follows:

[0130] Introduce an auxiliary velocity variable w, and define it as follows:

[0131] w=J(ψ)v+v r (13)

[0132] Then, equation (1) is transformed into

[0133]

[0134]

[0135]

[0136] Where χ represents the sum of unknown disturbances. For the desired trajectory, For the desired control input of the design;

[0137] Then, position error and velocity error are defined.

[0138] η e =η-η d (17)

[0139] w e =ww d (18)

[0140] in, The desired velocity vector;

[0141] The next step is to differentiate equations (17) and (18):

[0142]

[0143]

[0144] The design of the observer can effectively estimate the unknown velocity and the sum of all observed uncertainties. The process is as follows:

[0145]

[0146] in Let η be the estimated position of the unmanned surface vessel. This is an estimate of the assisted speed w of the unmanned vessel. Let χ be an estimated value, where χ is the sum of the uncertainties of the unmanned vessel, and its expression is:

[0147] χ=Γ+Δ+E+Z (22)

[0148] Where Γ represents the mismatch disturbance caused by ocean currents.

[0149]

[0150] Δ represents the matching disturbance caused by wind and waves in the marine environment.

[0151] Δ=J(ψ)M -1 d (24)

[0152] E represents the uncertainty term in the unmodeled part of the unmanned vessel dynamics.

[0153] E=J(ψ)R(r)vJ(ψ)M -1 C(v)-J(ψ)M -1 D(v) (25)

[0154] Z represents the uncertainty term caused by execution failure.

[0155]

[0156] Where, B(t-t0)=diag(b(tt) 01 ), b(tt 02 ), b(tt 03 E = diag(e) 11 e 22 e 33 ), τ n =[τ n1 , τ n2 , τ n3 ] T ,

[0157] By selecting appropriate parameters, the fixed-time extended state observer is uniformly fixed-time stable.

[0158] Given that the speed of the unmanned vessel is unknown, and considering the uncertainties of unmodeled dynamics, unknown disturbances, and actuator failures, an auxiliary speed estimate is needed using a fixed-time extended state observer. The sum of estimates of the uncertainty terms Feedback is then incorporated into the subsequent controller design to achieve stable operation of the unmanned vessel; ultimately, the control law is designed as follows:

[0159]

[0160] Where K η =diag(K) η1 K η2 K η3 ), K w =diag(K) w1 K w2 K w3 All of these are control gain matrices, and α1∈(0,1); while The auxiliary velocity estimation error is defined as follows:

[0161] In this embodiment, the appropriate parameter selection is as follows:

[0162] (1) λ3=1.1L w .

[0163] (2) δ>0 should be chosen to be sufficiently small, and at the same time The Herwitz matrix should be chosen, as follows:

[0164]

[0165] (3) Where T u It is a positive number.

[0166] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for controlling unmanned surface vessels based on a fixed-time extended state observer, characterized in that, Includes the following steps: Step S1: Acquire the status information of the unmanned vessel and the information data from various sensors, and send them to the control center; Step S2: The control center classifies and matches the information data according to the data type to obtain the corresponding status information of the unmanned vessel. Step S3: Based on disturbances, unmodeled dynamics, actuator failures, and unknown speeds in the marine environment, a fixed-time extended state observer is constructed to accurately estimate disturbances and uncertainties and compensate the controller, while obtaining the estimated values ​​of the unmanned vessel's auxiliary speed variables. Step S4: Specify the desired trajectory and subtract it from the actual position in the status information to obtain the position error; Step S5: Send the speed and total disturbance estimates, position error and desired trajectory to the fixed-time trajectory output feedback to the controller, and obtain the desired control input of the unmanned vessel through the controller; Step S6: Package and verify the control inputs, and send them to the main control unit of the unmanned vessel; Step S7: The main control unit executes control commands to complete the trajectory tracking task; Step S3 specifically involves: Step S31: Construct a mathematical model of the unmanned vessel; Step S32: Based on the mathematical model of the unmanned vessel, considering disturbances in the marine environment, unmodeled dynamics, actuator failures, and unknown speeds, construct a fixed-time extended state observer; The construction of the mathematical model for the unmanned vessel is as follows: The motion control problem of unmanned surface vessels (USVs) typically considers the planar motion of the USV and utilizes an inertial coordinate system (ISS). ) and attached coordinate system ( Establish a mathematical model for the unmanned vessel; Based on the motion characteristics of the fully driven unmanned vessel system, dynamic and kinematic equations are established, and its three-degree-of-freedom model expression is as follows: in, Let be the position vector of the unmanned vessel in the inertial coordinate system. This indicates the actual location of the unmanned vessel. The bow angle of the unmanned vessel; Let be the velocity vector of the unmanned surface vessel in the attached coordinate system. Forward speed, The drift speed, The bow roll angular velocity; The control vector is the input for the ship's propulsion control. For the driving force, For lateral drift force, For bow roll torque; This is to account for external disturbances such as wind and waves experienced by unmanned surface vessels in the attached coordinate system. For lateral interference force, For longitudinal interference force, For bow disturbance torque; This is due to mismatch interference caused by ocean currents; The matrix consists of the weight inertia of the unmanned vessel and the inertia added by hydrodynamics; This is the coordinate system transformation matrix; It is a Coriolis-centripetal matrix; This is the hydrodynamic damping parameter matrix; , , and The expressions are as follows: in, , , , , ; , , , , ; It's about the quality of the unmanned boat. For rotational inertia, Let be the distance between the center of gravity of the unmanned vessel and the origin in the attached coordinate system. , and The fluid dynamics derivative of the system; Transformation matrix It has the following properties in, The definition of First, the Coriolis-centripetal matrix Hydrodynamic damping parameter matrix and velocity vector All are unknown; in addition, considering the impact of actuator failure on the unmanned vessel control system, the control torque affected by actuator failure is expressed as in The actual control input for ship propulsion control; For the desired control input of the design; For the first The health status index of each actuator ranges from 0 to 1; The amount of erroneous input is unknown; For time index; where, ; The fixed-time extended state observer is constructed as follows: Introducing auxiliary speed variables and define it as follows. Then, equation (1) is transformed into in, The sum of unknown disturbances. For the desired trajectory, For the desired control input of the design; Then, position error and velocity error are defined. in, = The desired velocity vector; The next step is to differentiate equations (17) and (18): The design of the observer can effectively estimate the unknown velocity and the sum of all observed uncertainties. The process is as follows: in Location of the unmanned vessel The estimated value, Assisting unmanned vessels in speed The estimated value, for The estimated value, The sum of the uncertainties of the unmanned vessel is expressed as follows: in, Mismatched disturbances caused by ocean currents Matching disturbances caused by wind and waves in the marine environment Uncertainty terms in the unmodeled part of unmanned vessel dynamics Uncertainty term caused by execution failure in, , , , ; By selecting appropriate parameters, the fixed-time extended state observer is uniformly fixed-time stable. Given that the speed of the unmanned vessel is unknown, and considering the uncertainties of unmodeled dynamics, unknown disturbances, and actuator failures, an auxiliary speed estimate is needed using a fixed-time extended state observer. The sum of estimates of the uncertainty terms The feedback mechanism is then incorporated into the subsequent controller design to achieve stable operation of the unmanned vessel. Ultimately, the control law is designed as follows: in , Both are control gain matrices, and at the same time ;and The auxiliary velocity estimation error is defined as follows: .

2. The unmanned vessel control method based on a fixed-time extended state observer according to claim 1, characterized in that, The communication between the unmanned vessel and the control center is based on the TCP / IP protocol; the unmanned vessel master controller establishes a TCP server, which can establish connections with one or more TCP clients and read and write data; while the control center needs to have a TCP client to establish a connection with the unmanned vessel master controller.

3. The unmanned surface vessel control method based on a fixed-time extended state observer according to claim 1, characterized in that, After obtaining the status information of the unmanned vessel, the control center verifies the data returned by the unmanned vessel. The verification standard is to determine whether the returned data conforms to CRC16. If the verification fails, it means that the returned data is incorrect and the request needs to be resent. The returned new data needs to be verified again.

4. The unmanned vessel control method based on a fixed-time extended state observer according to claim 1, characterized in that, The time index is specifically... In equation (12), This represents the degree of failure of the actuator over time. This indicates the time when the fault occurred; If the actuator malfunctions, i.e. If the value is large, then It takes the form of a step function; similarly, when When the value is small, the actuator will slowly fail, which is called a slow-change failure.

5. The unmanned surface vessel control method based on a fixed-time extended state observer according to claim 1, characterized in that, The appropriate parameter selection is as follows: （1） ， ， ； (2) Choose one that is small enough, and at the same time The Herwitz matrix should be chosen, as follows: (3) ,in It is a positive number.

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