A disturbance rejection stability control method and system for a ship crane

Abstract

The application discloses a kind of anti-interference stable control method and system for marine crane, belong to ship crane anti-swing motion control technical field.To solve the problem that the existing technology ignores the coupling disturbance of the multi-degree-of-freedom of ship body roll, bow shake and heave, resulting in low load positioning accuracy and serious swing, the application first establishes a seven-degree-of-freedom dynamic model of marine crane system, and constructs an energy function.Then, according to the first derivative expression of the energy function, a disturbance compensation term is constructed to offset the disturbance caused by ship motion.Finally, based on the disturbance compensation term, a stable controller is designed to achieve precise positioning and swing elimination of the load.The application can compensate for the multi-source disturbance in complex sea conditions in real time, significantly improving the operation stability and control accuracy of the crane in the marine environment.

Description

Technical Field

[0001] This invention relates to the field of anti-sway motion control technology for ship cranes, and in particular to an anti-disturbance stability control method and system for ship cranes. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] In recent years, research on stability control technology for marine cranes has mainly focused on single disturbance compensation or low-degree-of-freedom motion modeling, achieving some progress under ideal sea conditions or simplified hull motion conditions. However, in actual marine operating environments, the hull is often simultaneously affected by multi-degree-of-freedom coupled motions such as roll, bow roll, and heave, causing significant fluctuations in the end-load position of the marine crane and severely reducing the positioning accuracy and operational stability of lifting operations. Multi-degree-of-freedom coupled motions of the hull refer to the simultaneous roll, bow roll, and heave motions of the hull in actual marine environments. These motions are coupled together and act on the crane system, leading to complex load dynamic characteristics. Especially for seven-degree-of-freedom marine cranes, with their complex mechanism configuration and strong joint coupling, the load-end control problem is more prominent under the excitation of complex hull motion, making it difficult for traditional control methods to effectively achieve high-precision stability compensation.

[0004] Existing technologies typically simplify hull disturbances, considering only the effects of motion in a single direction or a few degrees of freedom, failing to fully reflect the true dynamic characteristics of marine crane systems under the combined effects of roll, bow roll, and heave. Furthermore, research on the stability control of high-degree-of-freedom marine cranes is relatively insufficient, lacking effective methods for real-time compensation and precise control of the load end under complex hull motion conditions. This leads to problems such as load deviation from the target position during actual operations, resulting in swaying, drifting, and even positioning instability, making it difficult to meet the safety, stability, and control precision requirements of offshore lifting operations. Summary of the Invention

[0005] To address the limitations of considering only a single direction or a few degrees of freedom disturbances, which cannot effectively handle the impact of multi-degree-of-freedom coupled motions such as hull roll, bow roll, and heave on load positioning accuracy and stability, especially the lack of real-time compensation and precise control methods for cranes with complex high-degree-of-freedom configurations, this invention proposes an anti-disturbance stability control method and system for marine cranes. By establishing a dynamic model of a seven-degree-of-freedom marine crane system, constructing an energy function, and using its first derivative to build a disturbance compensation term, a stability controller is designed to achieve real-time compensation for complex hull disturbances, solving the problems of load swaying, drifting, and positioning instability.

[0006] On the one hand, a disturbance rejection stability control method for marine cranes is provided, including: Obtain the parameters of the marine crane system, and combine the ship's roll, yaw and heave motions to construct a seven-degree-of-freedom dynamic model of the marine crane system using the Lagrange modeling equations; Based on the dynamic model of the seven-degree-of-freedom marine crane system, an energy function is constructed. A disturbance compensation term is constructed based on the first derivative expression of the energy function, and the disturbance compensation term is used to counteract the disturbance caused by the hull motion. A stability controller is designed based on the disturbance compensation term, and the stability controller is used for control to realize the load positioning and anti-sway of the seven-degree-of-freedom marine crane system.

[0007] Furthermore, the dynamic model of the seven-degree-of-freedom marine crane system is as follows: ； in, Represents the inertia matrix. For the system's generalized coordinate vector, represent The second derivative, represent The first derivative, Represents the centripetal Coriolis force matrix. Represents the gravity vector. Represents the input vector. D This represents the perturbation vector.

[0008] Furthermore, the energy function includes a system kinetic energy term and a system potential energy term, wherein the system potential energy term includes the gravitational potential energy generated by the hook and load due to the swing angle.

[0009] Furthermore, the disturbance compensation term specifically includes: ; ; ; in, , , There are three disturbance compensation terms. , , and These are the masses of the base, cantilever, hook, and load, respectively. and These are the lengths of the base and the cantilever, respectively. The distance from the hook to the center of mass of the load. sgn( is the upper bound of the velocity of heave motion) ) is a symbolic function. , , They are respectively , and The first derivative, , and These represent the cantilever's undulation angle, rotation angle, and rope length, respectively. .

[0010] Furthermore, the expression for the stability controller is: ; in, , , , , For controller gain parameters, and The undulation torque and rotation torque of the cantilever are... For the lifting force of the rope, C5 = , For the anti-sway gain parameter, , , This is the error signal.

[0011] Furthermore, the stability controller is used for control, specifically by applying the undulation torque, rotation torque, and rope lifting force output by the stability controller to the undulation drive motor, rotation drive motor, and rope winch motor of the cantilever, respectively, to compensate for disturbances caused by the hull movement in real time, thereby achieving precise control of the load position and suppression of sway.

[0012] On the other hand, an anti-disturbance stability control system for marine cranes is provided, including: The model building module is configured to: acquire the parameters of the marine crane system, combine the ship's roll, yaw and heave motions, and use the Lagrange modeling equations to build a dynamic model of the seven-degree-of-freedom marine crane system; The energy function construction module is configured to construct an energy function based on the dynamic model of the seven-degree-of-freedom marine crane system. The disturbance compensation term construction module is configured to: construct a disturbance compensation term based on the first derivative expression of the energy function, wherein the disturbance compensation term is used to offset the disturbance caused by the hull motion; The controller design module is configured to: design a stabilizing controller based on the disturbance compensation term, and use the stabilizing controller for control to achieve load positioning and anti-sway of the seven-degree-of-freedom marine crane system.

[0013] Furthermore, the dynamic model of the seven-degree-of-freedom marine crane system is as follows: ; in, Represents the inertia matrix. For the system's generalized coordinate vector, represent The second derivative, represent The first derivative, Represents the centripetal Coriolis force matrix. Represents the gravity vector. Represents the input vector. D This represents the perturbation vector.

[0014] In another aspect, a computer device is also provided, including a computer-readable storage medium, a processor, and a computer program stored on the computer-readable storage medium and executable on the processor, characterized in that, when the processor executes the program, it performs the method described in the first aspect.

[0015] In another aspect, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, performs the method described in the first aspect.

[0016] The above technical solution has the following advantages or beneficial effects: This invention establishes a seven-degree-of-freedom marine crane model that simultaneously considers the ship's roll, bow roll, and heave motions. This overcomes the shortcomings of traditional methods that only consider disturbances in a single direction or a few degrees of freedom, and more realistically reflects the system's dynamic characteristics in the actual marine environment. Secondly, based on this model, a Lyapunov energy function incorporating both potential and kinetic energy is constructed. By analyzing the first derivative of the energy function, a disturbance compensation term is designed, leading to the derivation of a stabilization controller. This controller can achieve the positioning of the cantilever and load, and effectively suppresses the swaying of the marine crane load. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is an overall flowchart of the method in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the seven-degree-of-freedom marine crane structure in Embodiment 1 of the present invention; Figure 3 The figure shows the experimental results of the stable control method and PID controller in Embodiment 1 of the present invention; Figure 4 The figure shows the experimental results of the PID controller of the stable control method in Embodiment 1 of the present invention under different system parameters. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Those skilled in the art should understand that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0020] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] Example 1 To address the limitations of existing marine crane control strategies, which are often insufficient and difficult to apply to real-world three-dimensional motion environments, this embodiment provides an anti-disturbance stability control method capable of effectively handling multi-degree-of-freedom coupled disturbances of the hull. To solve the aforementioned technical problems, this embodiment first utilizes the Lagrange modeling method to establish a seven-degree-of-freedom marine crane dynamic model that comprehensively considers the hull's roll, yaw, and heave motions. Then, based on this model, a Lyapunov energy function incorporating the system's kinetic and potential energy is constructed. Next, a disturbance compensation term is designed based on the first-order time derivative of the energy function to counteract disturbances caused by the hull's motion. Finally, the specific form of the stability controller is derived based on the disturbance compensation term, thereby achieving precise positioning of the cantilever and load, and effective suppression of load sway. The following detailed description of this embodiment is provided in conjunction with the accompanying drawings.

[0022] like Figure 1 As shown in the figure, this embodiment provides an anti-disturbance stability control method for marine cranes, which includes the following steps: S101: Obtain the parameters of the marine crane system, combine the ship's roll, yaw and heave motions, and construct a seven-degree-of-freedom dynamic model of the marine crane system using the Lagrange modeling equations; S102: Constructing the energy function based on the dynamic model of a seven-degree-of-freedom marine crane system; S103: Construct a disturbance compensation term based on the first derivative expression of the energy function. The disturbance compensation term is used to offset the disturbances caused by the hull motion. S104: Design a stability controller based on disturbance compensation terms, and use the stability controller for control to realize load positioning and anti-sway of the seven-degree-of-freedom marine crane system.

[0023] In step S101, as follows Figure 2 As shown, Figure 2This is a schematic diagram of a seven-degree-of-freedom marine crane. First, the system parameters of the marine crane, including the mass, length, and moment of inertia of the base, cantilever, hook, and load, are obtained. To realistically reflect the impact of the actual marine environment on the crane, this embodiment also considers the roll, yaw, and heave motions of the hull under wave action, as well as the dynamic characteristics of the underwater load. Based on the above parameters and disturbance conditions, a dynamic model of the seven-degree-of-freedom marine crane system is constructed using the Lagrange modeling equation, the expression of which is:

[0024] in, For the system's generalized coordinate vector, =[ , , , , , ] T , represent The second derivative, represent The first derivative, and The two spatial swing angles represent the hook. and Two spatial angles (in the ship's coordinate system) representing the load. , , and This represents the swing angle of the hook and load in the inertial coordinate system. , and These represent the cantilever's undulation angle, rotation angle, and rope length, respectively. , , , and These represent the inertia matrix, the centripetal-Coriolis force matrix, the gravity vector, the input vector, and the disturbance vector, respectively. and The undulation moment and rotational moment represent the cantilever. This represents the lifting force of the rope. The specific expressions for the terms in the above matrix and vector are as follows:

[0025]

[0026]

[0027] in: , , and These represent the masses of the base, cantilever, hook, and load, respectively. and These represent the lengths of the base and the cantilever, respectively. This represents the distance from the hook to the center of mass of the load. The moment of inertia represents the rotation of the cantilever along the X-axis. The moment of inertia representing the cantilever along the Y-axis. The moment of inertia representing the cantilever along the Z-axis direction. The moment of inertia representing the base. Represents the gravitational acceleration constant. and They were used to represent and .

[0028] The parameters mentioned above together constitute a complete dynamic description of the system. This model accurately depicts the dynamic coupling effect of the ship's multi-degree-of-freedom motion on the crane's joints and load, laying the foundation for subsequent energy function construction and controller design.

[0029] In step S102, based on the dynamic model of the seven-degree-of-freedom marine crane system established above, an energy function is further constructed.

[0030] The total energy of a marine crane system consists of kinetic energy and potential energy. Kinetic energy is represented by a quadratic form of the generalized velocity and inertia matrix, while potential energy mainly includes the gravitational potential energy generated by the hook and load due to changes in the swing angle. To transform the system stability problem into an analysis of the rate of energy change, we first construct expressions for the energy functions of kinetic and potential energy, and then differentiate them to obtain the expression for the rate of energy change. The total energy of the system will change during the control process, but as long as the system energy stabilizes at the end, the overall system stability can be guaranteed. Therefore, the analysis of the rate of energy change is a key basis for controller design.

[0031] Specifically, the total energy function for constructing a seven-degree-of-freedom marine crane is: ; In step S103, based on the energy function constructed in the previous step, the first derivative with respect to time is calculated to obtain the rate of energy change. The initial expression: ; To reveal the specific impact of perturbations in each degree of freedom on energy changes, the above expressions are reorganized, like terms are combined, and simplified using relationships from the dynamic model, resulting in a clearer understanding. form: ; As can be seen from the simplified expression, the rate of energy change is determined by the control inputs for each degree of freedom, the disturbance term, and the gravity term. To stabilize the system, a suitable control law needs to be designed to counteract the effects of the disturbance term.

[0032] In step S104, based on the first-order derivative expression of the energy function obtained in step S103, a disturbance compensation term is first designed to counteract the disturbances caused by the hull motion. The disturbance compensation term is constructed specifically for the cantilever's undulation, rotation, and the cable's actuator, with the following detailed expressions:

[0033]

[0034]

[0035] in, , , These are three disturbance compensation terms. sgn (where sgn is the upper bound of the velocity of heave motion) ) is a sign function. , , They are respectively , and The first derivative, S 5= , C 5= .

[0036] Based on this, and considering the ship motion disturbance and gravity terms in the total energy change rate of the system, a stability controller is designed according to their correlation with the convergence of the energy function. This controller combines the disturbance compensation term with proportional-derivative control, gravity compensation, and nonlinear anti-sway term to ultimately obtain the undulation torque. Rotational torque and rope lifting force The expression: ; in: , , , , Represents the controller gain parameter. and The last one was designed to improve the transient performance (slippage reduction performance) of the control system. Indicates the control force of the rope. and For the anti-sway gain parameter, , , For error signals, , , , These represent the target angle and length of the cantilever undulation, rotation, and rope, respectively.

[0037] The fluctuating torque output by the aforementioned controller Rotational torque and rope lifting force The undulation drive motor, slewing drive motor, and rope winch motor, acting respectively on the cantilever, can compensate for disturbances caused by the ship's movement in real time, achieving precise load positioning and sway suppression for the seven-degree-of-freedom marine crane system. In this embodiment, the controller directly provides expressions for the undulation torque, slewing torque, and lifting force; therefore, torque control mode can be used to control the motors in actual control.

[0038] To verify the effectiveness of the method proposed in this embodiment, a simulation experiment was conducted. The experiment used a simulation platform built with Simulink in MATLAB. Two different sets of system parameters were selected (achieved by changing the load mass to verify the adaptability and robustness of the controller under different operating conditions). A traditional PID controller and the nonlinear stable controller proposed in this invention were used for comparative testing. The maximum positioning error (cantilever undulation angle, rotation angle, and rope length) and the longest anti-sway time were recorded. The results are shown in Table 1.

[0039] Table 1: Simulation comparison results.

[0040]

[0041] The simulation results show that the proposed method has no significant difference in control performance under different system parameters. It can fully position the cantilever and the hook load can converge to the equilibrium point after one cycle of swing. In contrast, the PID controller has large residual swing and positioning errors, indicating that the proposed method has good robustness.

[0042] Example 2 This embodiment provides an anti-disturbance stability control system for marine cranes, including: The model building module is configured to: acquire the parameters of the marine crane system, combine the ship's roll, yaw and heave motions, and use the Lagrange modeling equations to build a dynamic model of the seven-degree-of-freedom marine crane system; The energy function construction module is configured to: construct the energy function based on the dynamic model of a seven-degree-of-freedom marine crane system; The disturbance compensation term construction module is configured to construct a disturbance compensation term based on the first derivative expression of the energy function, wherein the disturbance compensation term is used to offset the disturbance caused by the hull motion; The controller design module is configured to: design a stable controller based on the disturbance compensation term, and use the stable controller for control to realize the load positioning and anti-sway of the seven-degree-of-freedom marine crane system.

[0043] It should be noted that each module in this embodiment corresponds one-to-one with each step in Embodiment 1, and their specific implementation process is the same, so it will not be repeated here.

[0044] Example 3 This embodiment also provides a computer device, including a computer-readable storage medium, a processor, and a computer program stored on the computer-readable storage medium and executable on the processor, characterized in that, when the processor executes the program, it completes the method described in Embodiment 1.

[0045] It should be understood that in this embodiment, the processor can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc.

[0046] Memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of memory may also include non-volatile random access memory. For example, memory may also store information about the device type.

[0047] In the implementation process, each step of the above method can be completed by the integrated logic circuits in the processor hardware or by software instructions.

[0048] The method in Embodiment 1 can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor. The software modules can reside in readily available storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory; the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, a detailed description is not provided here.

[0049] Those skilled in the art will recognize that the units and algorithm steps described in connection with the various examples of this embodiment can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention.

[0050] Example 4 This embodiment also provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, complete the method described in Embodiment 1.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A disturbance rejection stability control method for marine cranes, characterized in that, include: Obtain the parameters of the marine crane system, and combine the ship's roll, yaw and heave motions to construct a seven-degree-of-freedom dynamic model of the marine crane system using the Lagrange modeling equations; Based on the dynamic model of the seven-degree-of-freedom marine crane system, an energy function is constructed. A disturbance compensation term is constructed based on the first derivative expression of the energy function, and the disturbance compensation term is used to counteract the disturbance caused by the hull motion. A stability controller is designed based on the disturbance compensation term, and the stability controller is used for control to realize the load positioning and anti-sway of the seven-degree-of-freedom marine crane system.

2. The method according to claim 1, characterized in that, The dynamic model of the seven-degree-of-freedom marine crane system is as follows: ； in, Represents the inertia matrix. For the system's generalized coordinate vector, represent The second derivative, represent The first derivative, Represents the centripetal Coriolis force matrix. Represents the gravity vector. Represents the input vector. D This represents the perturbation vector.

3. The method according to claim 1, characterized in that, The energy function includes a system kinetic energy term and a system potential energy term, wherein the system potential energy term includes the gravitational potential energy generated by the hook and load due to the swing angle.

4. The method according to claim 1, characterized in that, The disturbance compensation term is specifically as follows: ； ； ； in, , , There are three disturbance compensation terms. , , and These are the masses of the base, cantilever, hook, and load, respectively. and These are the lengths of the base and the cantilever, respectively. The distance from the hook to the center of mass of the load. sgn( is the upper bound of the velocity of heave motion) ) is a symbolic function. , , They are respectively , and The first derivative, , and These represent the cantilever's undulation angle, rotation angle, and rope length, respectively. .

5. The method according to claim 1, characterized in that, The expression for the stabilizing controller is: ； in, , , , , For controller gain parameters, and The undulation torque and rotation torque of the cantilever are... For the lifting force of the rope, C5 = , For the anti-sway gain parameter, , , This is the error signal.

6. The method according to claim 1, characterized in that, The control is achieved by using the stabilizer controller, specifically by applying the undulation torque, rotation torque, and rope lifting force output by the stabilizer controller to the undulation drive motor, rotation drive motor, and rope winch motor of the cantilever, respectively, to compensate for disturbances caused by the hull movement in real time, thereby achieving precise control of the load position and suppression of sway.

7. An anti-disturbance stability control system for marine cranes, characterized in that, include: The model building module is configured to: acquire the parameters of the marine crane system, combine the ship's roll, yaw and heave motions, and use the Lagrange modeling equations to build a dynamic model of the seven-degree-of-freedom marine crane system; The energy function construction module is configured to construct an energy function based on the dynamic model of the seven-degree-of-freedom marine crane system. The disturbance compensation term construction module is configured to: construct a disturbance compensation term based on the first derivative expression of the energy function, wherein the disturbance compensation term is used to offset the disturbance caused by the hull motion; The controller design module is configured to: design a stabilizing controller based on the disturbance compensation term, and use the stabilizing controller for control to achieve load positioning and anti-sway of the seven-degree-of-freedom marine crane system.

8. The system according to claim 7, characterized in that, The dynamic model of the seven-degree-of-freedom marine crane system is as follows: ； in, Represents the inertia matrix. For the system's generalized coordinate vector, represent The second derivative, represent The first derivative, Represents the centripetal Coriolis force matrix. Represents the gravity vector. Represents the input vector. D This represents the perturbation vector.

9. A computer device comprising a computer-readable storage medium, a processor, and a computer program stored on the computer-readable storage medium and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the disturbance rejection and stability control method for marine cranes as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the disturbance rejection and stability control method for marine cranes as described in any one of claims 1-7.

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