A ship dynamic positioning adaptive finite time control system and control method

Abstract

The present invention provides a ship dynamic positioning adaptive finite time control system and a control method, which relate to the field of ship control technology. The ship dynamic positioning adaptive finite time control system comprises: a guiding device, a control device, an input saturation characteristic device, an interference estimation device and an auxiliary dynamic device. The present invention reduces the number of actuator actions and the wear of the actuator by setting a preset trigger condition in the control device, and solves the problem of reduced control accuracy caused by actuator saturation and even system divergence caused by the setting of the auxiliary dynamic device.

Description

Technical Field

[0001] The present invention relates to the field of ship control technology, and in particular to a ship dynamic positioning adaptive finite time control system and a control method. Background Art

[0002] As people pay more and more attention to the ocean and the exploration and development of marine resources, more and more research is being conducted on ship dynamic positioning control systems. The ship dynamic positioning system mainly uses the ship's actuators to enable it to maintain the preset desired position and heading under the influence of environmental interference. The use of ship dynamic positioning technology will not be restricted by water depth when performing maritime tasks, and it can work in complex and changeable sea conditions with good working performance. Therefore, ship dynamic positioning control systems are widely used in various marine environments and various types of ships, such as offshore drilling platforms, marine research vessels, cable laying ships, etc.

[0003] At present, the actuators of dynamic positioning vessels have saturation characteristics, and in most theoretical studies, the actuator saturation problem is ignored in the design process of dynamic positioning control systems, resulting in poor ship control performance. In addition, most literatures do not use finite time control technology and event triggering mechanism, which leads to slow system error convergence speed and easy wear of actuators. Summary of the invention

[0004] The problem solved by the present invention is how to eliminate the influence of the control system stability caused by the saturation of the actuator of the ship during the ship dynamic positioning control process, and at the same time improve the convergence speed and stability of the control system.

[0005] In order to solve the above problems, the present invention provides a ship dynamic positioning adaptive finite time control system: comprising: a guiding device, a control device, an input saturation characteristic device, an interference estimation device and an auxiliary dynamic device:

[0006] The guiding device is used to generate the expected posture at each moment according to the set expected position and the measured posture;

[0007] The control device is used to obtain a posture tracking error vector according to the desired posture and the measured posture, obtain a virtual control law according to the posture tracking error vector, obtain a temporary control law according to the virtual control law, the measured speed, the output of the interference estimation device and the output of the auxiliary dynamic device, and obtain a target control law according to a preset trigger condition, the temporary control law target and the output of the control device at the previous moment;

[0008] The input saturation characteristic device is used to obtain the final control law according to the preset saturation law and the target control law, and transmit it to the actuator of the ship;

[0009] The auxiliary dynamic device is used to obtain a control law deviation according to the target control law and the final control law, and output auxiliary dynamics according to the control law deviation;

[0010] The disturbance estimation device is used for outputting a disturbance estimation value according to the measured speed, the virtual control law and the auxiliary dynamics.

[0011] Optionally, the interference estimation value includes:

[0012] ;

[0013] in, , is the measured speed, is the virtual control law, is the longitudinal velocity tracking error, is the lateral velocity tracking error, is the heading angular velocity tracking error, For the auxiliary dynamics, for The estimated value of for The derivative of the estimate of , is the adaptive law, , is the input vector of the neural network, is the ideal weight matrix, , is the number of neurons, , , where the components are Gaussian basis functions.

[0014] Optionally, the adaptive law includes:

[0015] ;

[0016] in, , and is a positive definite matrix, , , is the symbolic function, for The derivative of .

[0017] Optionally, obtaining a virtual control law according to the posture tracking error vector includes:

[0018] The virtual control law is obtained by formula 1;

[0019] The formula 1 is:

[0020] ;

[0021] Wherein, z1 is the posture tracking error vector, , is the measured posture, is the desired pose, is the derivative of the desired pose, is the longitudinal position tracking error, is the lateral position tracking error, is the heading angle tracking error, and is a positive definite matrix, is the transformation matrix between the earth coordinate system and the ship coordinate system, , , is a symbolic function.

[0022] Optionally, obtaining a temporary control law according to the virtual control law, the measured speed, the output of the disturbance estimation device and the output of the auxiliary dynamic device comprises:

[0023] Obtaining a speed tracking error vector according to the virtual control law and the measured speed;

[0024] A temporary control law is obtained according to the virtual control law, the speed tracking error vector, the output of the disturbance estimation device and the output of the auxiliary dynamic device.

[0025] Optionally, obtaining a temporary control law according to the virtual control law, the speed tracking error vector, the output of the disturbance estimation device and the output of the auxiliary dynamic device comprises:

[0026] Obtaining a dynamic control law according to the virtual control law, the speed tracking error vector, the output of the disturbance estimation device and the output of the auxiliary dynamic device;

[0027] Obtaining the temporary control law according to the dynamic control law;

[0028] Wherein, the dynamic control law is:

[0029] ;

[0030] in, , , and is a positive definite matrix, , , is the symbolic function, is the inertia matrix of the ship system, is the derivative of the virtual control law.

[0031] Optionally, obtaining the temporary control law according to the dynamic control law includes:

[0032] The temporary control law is obtained by formula 2;

[0033] ;

[0034] in, , are the components of the temporary control law in the longitudinal, lateral and bow directions, respectively, is the third-order identity matrix, is a third-order positive definite diagonal matrix with diagonal elements , and is a positive constant, and z2 is the velocity tracking error vector.

[0035] Optionally, outputting auxiliary dynamics according to the control law deviation includes:

[0036] The auxiliary dynamics are obtained by formula 3:

[0037] The formula three is:

[0038] ;

[0039] in, , which is the control law deviation, is the target control law, is the final control law, and is a positive definite matrix, is the inertia matrix of the ship system, For the auxiliary dynamics, is the derivative of the auxiliary dynamics, , , is a symbolic function.

[0040] Optionally, obtaining the target control law according to the preset trigger condition, the temporary control law target and the output of the control device at the last moment includes:

[0041] Obtaining an error vector according to the temporary control law target and the output of the control device at the previous moment;

[0042] When the error vector satisfies the preset trigger condition, the temporary control law is the target control law;

[0043] When the error vector does not satisfy the preset trigger condition, the output of the control device at the previous moment is the target control law;

[0044] The output of the control device at the previous moment is the target control law at the previous moment.

[0045] The advantages of the ship dynamic positioning adaptive finite time control system described in the present invention over the prior art are:

[0046] By introducing a control device, a virtual control law is obtained according to the output of the guidance device (expected posture) and the measured posture, and a temporary control law is obtained through the virtual control law, the measured posture, the output of the interference device (interference estimate) and the output of the auxiliary dynamic device (auxiliary dynamic). According to the temporary control law and the output of the control device at the previous moment, it is determined whether to trigger based on the preset trigger condition, and the target control law is obtained, wherein the preset trigger condition, that is, the setting of the trigger mechanism, is to reduce the number of actuator actions and reduce the actuator wear; and the output of the control device (target control law) is set based on the finite time control theory, which can make the tracking error converge within a finite time.

[0047] The input saturation characteristic device obtains the final control law according to the preset saturation law and the target control law, wherein the preset saturation law is set based on the saturation of the ship's actuator. If the actuator is in an unsaturated state, that is, when it meets the range of the preset saturation law, there is no need to adjust the target control law, and it can be directly transferred to the actuator. If the actuator is in a saturated state, that is, when it does not meet the range of the preset saturation law, it is necessary to adjust the target control law, and the adjusted target control is output (final control law) to the actuator. The poor stability caused by the saturation of the actuator is solved by the input saturation characteristic device; and the auxiliary dynamics is obtained according to the difference between the target control law and the final control law (the output of the auxiliary dynamics device), that is, when the actuator is saturated, the system will generate auxiliary dynamics and transmit them to the interference estimation device and the control device. The output of the interference estimation device (interference estimation value) is transmitted to the control device. The control device adjusts the output at the next moment based on the interference estimation value and the auxiliary dynamics, thereby solving the saturation of the actuator structure, wherein the interference estimation includes unknown model parameters and environmental interference.

[0048] Therefore, the present invention can quickly obtain the tracking error of the ship through the control device and make it converge quickly within a finite time, taking into account the uncertainty of the dynamic positioning ship model, the interference of the external environment and the saturation of the actuator. The temporary control law is obtained through the virtual control law, the measured posture, the output of the interference device (the interference estimate) and the output of the auxiliary dynamic device (the auxiliary dynamic). The finite time control theory is adopted, so that the tracking error can converge within a finite time, that is, the entire control system is finite time stable, which improves the error convergence speed, speeds up the speed of the ship to reach the desired set point, and enhances the control performance; based on the prevention of trigger conditions (trigger mechanism), it is judged whether to trigger, the number of actuator actions is reduced, the actuator wear is reduced, and the control performance of the control system is improved. The preset saturation law of the input saturation characteristic device and the setting of the auxiliary dynamic device solve the problem of reduced control accuracy caused by actuator saturation and even system divergence.

[0049] In order to solve the above technical problems, the present invention also provides a ship dynamic positioning adaptive finite time control method, which is applied to the ship dynamic positioning adaptive finite time control system. The ship dynamic positioning adaptive finite time control method comprises:

[0050] Generate the expected posture at each moment according to the set expected position and measured posture;

[0051] Obtaining a posture tracking error vector according to the desired posture and the measured posture, and obtaining a virtual control law according to the posture tracking error vector;

[0052] Obtaining a temporary control law according to the virtual control law, the measured speed, the interference estimation value and the auxiliary dynamics, wherein the interference estimation value is obtained according to the measured speed, the virtual control law and the auxiliary dynamics;

[0053] Obtaining a target control law according to a preset trigger condition, the temporary control law target and the output of a control device in the ship dynamic positioning adaptive finite time control system at a previous moment;

[0054] Obtaining a final control law according to a preset saturation law and the target control law;

[0055] The auxiliary dynamics is obtained according to the difference between the target control law and the final control law.

[0056] The ship dynamic positioning adaptive finite time control method described in the present invention and the ship dynamic positioning adaptive finite time control system have the same advantages over the prior art, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1It is a structural diagram of an adaptive finite time control system for ship dynamic positioning in an embodiment of the present invention;

[0058] Figure 2 The figure is a flow chart of the adaptive finite time control method for ship dynamic positioning in an embodiment of the present invention. DETAILED DESCRIPTION

[0059] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0060] To solve the above problems, Figure 1 As shown, the present invention provides a ship dynamic positioning adaptive finite time control system, including: a guiding device, a control device, an input saturation characteristic device, a disturbance estimation device and an auxiliary dynamic device;

[0061] Specifically, the guidance device receives the measured posture, and the control device receives the output of the guidance device, the measured posture, the output of the interference estimation device, the output of the input saturation characteristic device and the output of the auxiliary dynamic device respectively; the output of the control device is transmitted to the input saturation characteristic device and the auxiliary dynamic device, and the obtained virtual control law is transmitted to the interference estimation device; the output of the input saturation characteristic device is transmitted to the actuator and the auxiliary dynamic device of the ship, and the output of the auxiliary dynamic device is transmitted to the control device and the interference estimation device.

[0062] The guiding device is used to generate the expected posture at each moment according to the set expected position and the measured posture;

[0063] Specifically, the measured position and posture of the ship is obtained through the sensor device of the ship; and the expected position and posture at each moment is generated according to the expected position and the measured position and posture.

[0064] Constructing a three-degree-of-freedom mathematical model of a dynamically positioned vessel:

[0065] ;

[0066] in, is the horizontal position and heading angle vector (position and attitude) of the dynamic positioning vessel in the geodetic coordinate system, is the longitudinal position of the ship, is the transverse position of the ship, is the ship heading angle; for The derivative of (the measured position of the ship). is the speed and angular velocity vector of the ship in the hull coordinate system (the measured speed of the ship), is the longitudinal speed of the ship, is the ship's transverse speed, is the ship's pitch angular velocity, for The derivative of (the speed of the ship), is the actual control force and torque vector acting on the ship (final control law), is the longitudinal thrust of the ship, is the lateral thrust of the ship, is the ship bow turning moment, represents the unknown time-varying environmental disturbance vector to which the ship is subjected, is the disturbance force on the ship longitudinally, is the disturbance force on the ship in the lateral direction, is the disturbance moment on the ship’s bow, represents the inertia matrix of the ship system, represents the ship damping matrix, is the transformation matrix between the earth coordinate system and the ship coordinate system, in the form of:

[0067] ;

[0068] For the sake of simplicity in the following text, define .

[0069] The control device is used to obtain a posture tracking error vector according to the desired posture and the measured posture, obtain a virtual control law according to the posture tracking error vector, obtain a temporary control law according to the virtual control law, the measured speed, the output of the interference estimation device and the output of the auxiliary dynamic device, and obtain a target control law according to a preset trigger condition, the temporary control law target and the output of the control device at the previous moment;

[0070] Specifically, a posture tracking error vector is obtained according to the expected posture and the measured posture; a virtual control law is obtained according to the posture tracking error vector, and a temporary control law is obtained through the virtual control law, the measured posture (obtained by the ship's sensor device), the output of the interference device (interference estimation value) and the output of the auxiliary dynamic device (auxiliary dynamic), and according to the temporary control law and the output of the control device at the previous moment (target control law), it is determined whether to trigger based on the preset trigger condition, and the target control law is obtained. The control device has a holding (memory) function, that is, it keeps its own output at the previous moment; wherein the preset trigger condition, that is, the setting of the trigger mechanism, is to reduce the number of actuator actions and reduce actuator wear; and the output of the control device (target control law) is set based on the finite time control theory, which can make the tracking error converge within a finite time.

[0071] The input saturation characteristic device is used to obtain the final control law according to the preset saturation law and the target control law, and transmit it to the actuator of the ship;

[0072] Specifically, the preset saturation law is obtained based on the input saturation characteristics of the actuator, that is:

[0073] ;

[0074] in, , and Respectively represent the maximum and minimum values ​​of thrust and torque generated by the actuator (that is, the range of the preset control law is ( , )). represents the target control law (designed control instructions), is the longitudinal control command of the target control law, is the lateral control command of the target control law, is the heading control command of the target control law, the deviation between the control command and the actual control force and torque , is the deviation (control law deviation) between the control command (target control law) and the actual control force and torque (final control law), is the target control law, is the final control law.

[0075] Specifically, when the input saturates the device input (controlling the device output) Greater than When , the output of the input saturation characteristic device (final control law) is , when the input saturates the characteristic device input (control device output) Less than When , the output of the input saturation characteristic device (final control law) is , when the input saturates the characteristic device input (control device output) Less than , and greater than When , the output of the input saturation characteristic device (final control law) is Because the preset saturation law is set based on the input saturation characteristic of the actuator, the input saturation characteristic device solves the problems of poor stability and system divergence caused by the saturation of the actuator, thereby improving the control accuracy and stability of the control system.

[0076] The mathematical model of a dynamically positioned ship can be written as:

[0077] ;

[0078] .

[0079] The auxiliary dynamic device is used to obtain a control law deviation according to the target control law and the final control law, and output auxiliary dynamics according to the control law deviation;

[0080] Specifically, the auxiliary dynamics is obtained based on the difference between the target control law and the final control law (the output of the auxiliary dynamics device). That is, when the actuator is saturated, the system will generate auxiliary dynamics and transmit them to the interference estimation device and the control device. The output of the interference estimation device (interference estimation value) is transmitted to the control device. The control device adjusts the output at the next moment based on the interference estimation value and the auxiliary dynamics, thereby solving the saturation of the execution structure.

[0081] The disturbance estimation device is used to output the disturbance estimation value according to the measured speed, the virtual control law and the auxiliary dynamics:

[0082] Specifically, since the virtual control law and the auxiliary dynamics are both set based on the finite-time control theory, the interference estimation value is obtained based on the measured speed, the virtual control law and the auxiliary dynamics, that is, the interference estimation value is based on the finite-time control theory, and the output of the interference estimation device (interference estimation value) is transmitted to the control device. The control device adjusts the output at the next moment based on the interference estimation value and the auxiliary dynamics, thereby solving the saturation problem of the execution structure.

[0083] The ship dynamic positioning adaptive finite time control system described in this embodiment introduces a control device, obtains a virtual control law according to the output of the guidance device (expected posture) and the measured posture, obtains a temporary control law through the virtual control law, the measured posture, the output of the interference device (interference estimate) and the output of the auxiliary dynamic device (auxiliary dynamic), and determines whether to trigger based on the preset trigger condition according to the temporary control law and the output of the control device at the previous moment, and obtains the target control law, wherein the preset trigger condition, that is, the setting of the trigger mechanism, is to reduce the number of actuator actions and reduce actuator wear; and the output of the control device (target control law) is set based on the finite time control theory, which can make the tracking error converge within a finite time.

[0084] The input saturation characteristic device obtains the final control law according to the preset saturation law and the target control law, wherein the preset saturation law is set based on the saturation of the ship's actuator. If the actuator is in an unsaturated state, that is, when it meets the range of the preset saturation law, there is no need to adjust the target control law, and it can be directly transferred to the actuator. If the actuator is in a saturated state, that is, when it does not meet the range of the preset saturation law, it is necessary to adjust the target control law, and the adjusted target control is output (final control law) to the actuator. The poor stability caused by the saturation of the actuator is solved by the input saturation characteristic device; and the auxiliary dynamics is obtained according to the difference between the target control law and the final control law (the output of the auxiliary dynamics device), that is, when the actuator is saturated, the system will generate auxiliary dynamics and transmit them to the interference estimation device and the control device. The output of the interference estimation device (interference estimation value) is transmitted to the control device. The control device adjusts the output at the next moment based on the interference estimation value and the auxiliary dynamics, thereby solving the saturation of the actuator structure, wherein the interference estimation includes unknown model parameters and environmental interference.

[0085] Therefore, the present invention can quickly obtain the tracking error of the ship through the control device and make it converge quickly within a finite time, taking into account the uncertainty of the dynamic positioning ship model, the interference of the external environment and the saturation of the actuator. The temporary control law is obtained through the virtual control law, the measured posture, the output of the interference device (the interference estimate) and the output of the auxiliary dynamic device (the auxiliary dynamic). The finite time control theory is adopted, so that the tracking error can converge within a finite time, that is, the entire control system is finite time stable, which improves the error convergence speed, speeds up the speed of the ship to reach the desired set point, and enhances the control performance; based on the prevention of trigger conditions (trigger mechanism), it is judged whether to trigger, the number of actuator actions is reduced, the actuator wear is reduced, and the control performance of the control system is improved. The preset saturation law of the input saturation characteristic device and the setting of the auxiliary dynamic device solve the problem of reduced control accuracy caused by actuator saturation and even system divergence.

[0086] The obtaining of a virtual control law according to the posture tracking error vector comprises:

[0087] The virtual control law is obtained by formula 1;

[0088] The formula 1 is:

[0089] ;

[0090] Wherein, z1 is the posture tracking error vector, , is the measured posture, is the desired pose, is the derivative of the desired pose, and is a positive definite matrix, is the transformation matrix between the earth coordinate system and the ship coordinate system, , , is a symbolic function.

[0091] Specifically, a posture tracking error vector is obtained according to the expected posture and the measured posture;

[0092] ;

[0093] in, is the measured posture, To guide the desired position of the device,

[0094] right The derivation is,

[0095] ;

[0096] in, is the derivative of the desired pose.

[0097] The step of obtaining a temporary control law according to the virtual control law, the measured speed, the output of the disturbance estimation device and the output of the auxiliary dynamic device comprises:

[0098] Obtaining a speed tracking error vector according to the virtual control law and the measured speed;

[0099] A temporary control law is obtained according to the virtual control law, the speed tracking error vector, the output of the disturbance estimation device and the output of the auxiliary dynamic device.

[0100] The step of obtaining a temporary control law according to the virtual control law, the speed tracking error vector, the output of the disturbance estimation device and the output of the auxiliary dynamic device comprises:

[0101] Obtaining a dynamic control law according to the virtual control law, the speed tracking error vector, the output of the disturbance estimation device and the output of the auxiliary dynamic device;

[0102] The temporary control law is obtained according to the dynamic control law.

[0103] Specifically, the speed tracking error vector is obtained through the virtual control law and the measured speed;

[0104] ;

[0105] in, is the measured speed, is the virtual control law, is the auxiliary dynamic.

[0106] right Derivative, and multiply by the inertia matrix on the left We can get:

[0107] ;

[0108] for The derivative of For synthetic interference, is the derivative of the virtual control law. Contains unknown model parameters and environmental interference, so the radial basis neural network is used to approximate it:

[0109] ;

[0110] in, is the input vector of the neural network, is the ideal weight matrix, , is the number of neurons, is the approximation error, and . , , where the components are Gaussian basis functions.

[0111] Since the ideal weight matrix is ​​complex and unknown, in order to reduce the online learning time of the neural network, based on the minimum learning parameter algorithm, we define ,The minimum learning parameter algorithm is adopted to reduce the online parameter learning time of the neural network and reduce the computational burden.

[0112] The output of the interference estimation device, that is, the interference estimation value, is:

[0113] ;

[0114] in, Synthetic interference The estimated value of , is the measured speed, is the virtual control law, For the auxiliary dynamics, for The estimated value of is the adaptive law, ; is the input vector of the neural network, is the ideal weight matrix, , is the number of neurons, , , where the components are Gaussian basis functions.

[0115] And set The adaptive law of:

[0116] ;

[0117] in, , and is a positive definite matrix, , , is the symbolic function, for The derivative of .

[0118] The dynamic control law is:

[0119] ;

[0120] in, , , and is a positive definite matrix, , , is the symbolic function, is the inertia matrix of the ship system, is the derivative of the virtual control law.

[0121] The temporary control law is obtained according to the dynamic control law, including:

[0122] The temporary control law is obtained by formula 2;

[0123] ;

[0124] in, , is the third-order identity matrix, is a third-order positive definite diagonal matrix with diagonal elements , and is a positive constant, and z2 is the velocity tracking error vector.

[0125] Specifically, in order to reduce the number of actuator actions and reduce wear, a temporary control law is set according to the event trigger mechanism;

[0126] The preset trigger conditions, that is, the event trigger mechanism is:

[0127] ;

[0128] ;

[0129] in, and , are the current moment and the next moment of control law update, respectively. .

[0130] Outputting auxiliary dynamics according to the control law deviation includes:

[0131] The auxiliary dynamics are obtained by formula 3:

[0132] The formula three is:

[0133] ;

[0134] in, , which is the control law deviation, is the target control law, is the final control law, and is a positive definite matrix, is the inertia matrix of the ship system, For the auxiliary dynamics, is the derivative of the auxiliary dynamics, , , is a symbolic function.

[0135] The obtaining of the target control law according to the preset trigger condition, the temporary control law target and the output of the control device at the last moment comprises:

[0136] Obtaining an error vector according to the temporary control law target and the output of the control device at the previous moment;

[0137] When the error vector satisfies the preset trigger condition, the temporary control law is the target control law;

[0138] When the error vector does not satisfy the preset trigger condition, the output of the control device at the previous moment is the target control law; wherein, the output of the control device at the previous moment is the target control law at the previous moment.

[0139] Specifically, according to the current temporary control law target and the temporary control law at the previous moment, a judgment is made based on the preset trigger condition. When the error vector meets the preset trigger condition, that is, it is triggered, the current temporary control law is used as the output of the control device (target control law); if the error vector does not meet the preset trigger condition, that is, it is not triggered, the output of the control device at the previous moment is used as the output of the control device (target control law).

[0140] The ship dynamic positioning adaptive finite time control system described in this embodiment introduces a control device, obtains a virtual control law according to the output of the guidance device (expected posture) and the measured posture, obtains a temporary control law through the virtual control law, the measured posture, the output of the interference device (interference estimate) and the output of the auxiliary dynamic device (auxiliary dynamic), and determines whether to trigger based on the preset trigger condition according to the temporary control law and the output of the control device at the previous moment, and obtains the target control law, wherein the preset trigger condition, that is, the setting of the trigger mechanism, is to reduce the number of actuator actions and reduce actuator wear; and the output of the control device (target control law) is set based on the finite time control theory, which can make the tracking error converge within a finite time.

[0141] The input saturation characteristic device obtains the final control law according to the preset saturation law and the target control law, wherein the preset saturation law is set based on the saturation of the ship's actuator. If the actuator is in an unsaturated state, that is, when it meets the range of the preset saturation law, there is no need to adjust the target control law, and it can be directly transferred to the actuator. If the actuator is in a saturated state, that is, when it does not meet the range of the preset saturation law, it is necessary to adjust the target control law, and the adjusted target control is output (final control law) to the actuator. The poor stability caused by the saturation of the actuator is solved by the input saturation characteristic device; and the auxiliary dynamics is obtained according to the difference between the target control law and the final control law (the output of the auxiliary dynamics device), that is, when the actuator is saturated, the system will generate auxiliary dynamics and transmit them to the interference estimation device and the control device. The output of the interference estimation device (interference estimation value) is transmitted to the control device. The control device adjusts the output at the next moment based on the interference estimation value and the auxiliary dynamics, thereby solving the saturation of the actuator structure, wherein the interference estimation includes unknown model parameters and environmental interference.

[0142] Therefore, the present invention can quickly obtain the tracking error of the ship through the control device and make it converge quickly within a finite time, taking into account the uncertainty of the dynamic positioning ship model, the interference of the external environment and the saturation of the actuator. The temporary control law is obtained through the virtual control law, the measured posture, the output of the interference device (the interference estimate) and the output of the auxiliary dynamic device (the auxiliary dynamic). The finite time control theory is adopted, so that the tracking error can converge within a finite time, that is, the entire control system is finite time stable, which improves the error convergence speed, speeds up the speed of the ship to reach the desired set point, and enhances the control performance; based on the prevention of trigger conditions (trigger mechanism), it is judged whether to trigger, the number of actuator actions is reduced, the actuator wear is reduced, and the control performance of the control system is improved. The preset saturation law of the input saturation characteristic device and the setting of the auxiliary dynamic device solve the problem of reduced control accuracy caused by actuator saturation and even system divergence.

[0143] like Figure 2 As shown, another embodiment of the present invention provides a ship dynamic positioning adaptive finite time control method, which is applied to the ship dynamic positioning adaptive finite time control system, and the ship dynamic positioning adaptive finite time control method includes:

[0144] Generate the expected posture at each moment according to the set expected position and measured posture;

[0145] Obtaining a posture tracking error vector according to the desired posture and the measured posture, and obtaining a virtual control law according to the posture tracking error vector;

[0146] Obtaining a temporary control law according to the virtual control law, the measured speed, the interference estimation value and the auxiliary dynamics, wherein the interference estimation value is obtained according to the measured speed, the virtual control law and the auxiliary dynamics;

[0147] Obtaining a target control law according to a preset trigger condition, the temporary control law target and the output of a control device in the ship dynamic positioning adaptive finite time control system at a previous moment;

[0148] A final control law is obtained according to the preset saturation law and the target control law, and transmitted to the actuator of the ship;

[0149] The auxiliary dynamics is obtained according to the difference between the target control law and the final control law.

[0150] It should be noted that, in this article, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0151] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features invented herein.

[0152] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. An adaptive finite time control system for ship dynamic positioning, characterized in that: The ship dynamic positioning adaptive finite time control system comprises: a guiding device, a control device, an input saturation characteristic device, a disturbance estimation device and an auxiliary dynamic device: The guiding device is used to generate the expected posture at each moment according to the set expected position and the measured posture; The control device is used to obtain a posture tracking error vector according to the desired posture and the measured posture, obtain a virtual control law according to the posture tracking error vector, obtain a temporary control law according to the virtual control law, the measured speed, the output of the interference estimation device and the output of the auxiliary dynamic device, and obtain a target control law according to a preset trigger condition, the temporary control law target and the output of the control device at the previous moment; The input saturation characteristic device is used to obtain the final control law according to the preset saturation law and the target control law, and transmit it to the actuator of the ship; The auxiliary dynamic device is used to obtain a control law deviation according to the target control law and the final control law, and output auxiliary dynamics according to the control law deviation; The disturbance estimation device is used for outputting a disturbance estimation value according to the measured speed, the virtual control law and the auxiliary dynamics.

2. The ship dynamic positioning adaptive finite time control system according to claim 1, characterized in that: The interference estimate includes: Where z2 is the velocity tracking error vector, z2=[z 21 ,z 22 ,z 23 ] T =υ-α-ξ, υ is the measured speed, α is the virtual control law, z 21 is the longitudinal velocity tracking error, z 22 is the lateral velocity tracking error, z 23 is the heading angular velocity tracking error, ξ is the auxiliary dynamics, for The estimated value of for The derivative of the estimate of , is the square of the 2-norm of the ideal weight matrix W, X=[η T ,υ T ] T is the input vector of the neural network, is the ideal weight matrix, is the component of the ideal weight matrix, m is the number of neurons, h(X) is a radial basis function vector, where the components are Gaussian basis functions.

3. The ship dynamic positioning adaptive finite time control system according to claim 2, characterized in that: Adaptive laws include: Among them, γ1, k w1 and k w2 is a positive definite matrix, sig ρ (·) is the preset function, defined as sig ρ (·)=|·| ρ sign(·), ρ is the preset parameter, 0<ρ<1, sign(·) is the sign function, for The derivative of .

4. The ship dynamic positioning adaptive finite time control system according to claim 1, characterized in that: The obtaining of a virtual control law according to the posture tracking error vector comprises: The virtual control law is obtained by formula 1; The formula 1 is: Wherein, z1 is the posture tracking error vector, z1=[z 11 ,z 12 ,z 13 ] T =η-η d , η is the measured pose, η d is the desired pose, is the derivative of the desired pose, z 11 is the longitudinal position tracking error, z 12 is the lateral position tracking error, z 13 is the heading angle tracking error, k1 and k2 are positive definite preset matrices, R is the transformation matrix between the earth coordinate system and the hull coordinate system, sig ρ (·) is the preset function, defined as sig ρ (·)=|·| ρ sign(·), ρ is the preset parameter, 0<ρ<1, sign(·) is the sign function.

5. The ship dynamic positioning adaptive finite time control system according to claim 2, characterized in that: The temporary control law is obtained according to the virtual control law, the measured speed, the output of the disturbance estimation device and the output of the auxiliary dynamic device, including: Obtaining a speed tracking error vector according to the virtual control law and the measured speed; A temporary control law is obtained according to the virtual control law, the speed tracking error vector, the output of the disturbance estimation device and the output of the auxiliary dynamic device.

6. The ship dynamic positioning adaptive finite time control system according to claim 5, characterized in that: The step of obtaining a temporary control law according to the virtual control law, the speed tracking error vector, the output of the disturbance estimation device and the output of the auxiliary dynamic device comprises: Obtaining a dynamic control law according to the virtual control law, the speed tracking error vector, the output of the disturbance estimation device and the output of the auxiliary dynamic device; Obtaining the temporary control law according to the dynamic control law; Wherein, the dynamic control law is: Among them, k3, k4, λ1 and λ2 are positive definite matrices, sig ρ (·) is the preset function, defined as sig ρ (·)=|·| ρ sign(·), ρ is the preset parameter, 0<ρ<1, sign(·) is the sign function, M is the inertia matrix of the ship system, is the derivative of the virtual control law, Z2 is the speed tracking error vector, and ξ is the auxiliary dynamics.

7. The ship dynamic positioning adaptive finite time control system according to claim 6, characterized in that: The step of obtaining the temporary control law according to the dynamic control law comprises: The temporary control law is obtained by formula 2; in, are the components of the temporary control law in the longitudinal, transverse and bow directions, respectively, I is a third-order identity matrix, σ is a third-order positive definite diagonal matrix, and the diagonal elements 0<σ ii <1,i=1,2,3, and ζ are positive constants, and z2 is the velocity tracking error vector.

8. The ship dynamic positioning adaptive finite time control system according to claim 1, characterized in that: The outputting auxiliary dynamics according to the control law deviation comprises: The auxiliary dynamics are obtained by formula 3: The formula three is: Among them, Δ τ =τ-τ c , which is the control law deviation, τ c is the target control law, τ is the final control law, λ1 and λ2 are positive definite preset matrices, M is the ship system inertia matrix, ξ is the auxiliary dynamics, is the derivative of the auxiliary dynamics, sig ρ (·) is the preset function, defined as sig ρ (·)=|·| ρ sign(·), ρ is the preset parameter, 0<ρ<1, sign(·) is the sign function.

9. The ship dynamic positioning adaptive finite time control system according to claim 1, characterized in that: The obtaining of the target control law according to the preset trigger condition, the temporary control law target and the output of the control device at the last moment comprises: Obtaining an error vector according to the temporary control law target and the output of the control device at the previous moment; When the error vector satisfies the preset trigger condition, the temporary control law is the target control law; When the error vector does not satisfy the preset trigger condition, the output of the control device at the previous moment is the target control law; The output of the control device at the previous moment is the target control law at the previous moment.

10. A ship dynamic positioning adaptive finite time control method, characterized in that: Applied to the ship dynamic positioning adaptive finite time control system according to any one of claims 1 to 9, the ship dynamic positioning adaptive finite time control method comprises: Generate the expected posture at each moment according to the set expected position and measured posture; Obtaining a posture tracking error vector according to the desired posture and the measured posture, and obtaining a virtual control law according to the posture tracking error vector; Obtaining a temporary control law according to the virtual control law, the measured speed, the interference estimation value and the auxiliary dynamics, wherein the interference estimation value is obtained according to the measured speed, the virtual control law and the auxiliary dynamics; Obtaining a target control law according to a preset trigger condition, the temporary control law target and the output of a control device in the ship dynamic positioning adaptive finite time control system at a previous moment; A final control law is obtained according to the preset saturation law and the target control law, and transmitted to the actuator of the ship; The auxiliary dynamics is obtained according to the difference between the target control law and the final control law.

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