Non-singular terminal sliding mode control method and system for marine rotary crane

Abstract

The invention discloses a nonsingular terminal sliding mode control method and system for a marine rotary crane, and the method comprises the steps: obtaining related parameters of a four-degree-of-freedom marine rotary crane, and building a first mathematical model; establishing a first equation and a second equation based on the first mathematical model; an equation is combined with the improved non-singular fast terminal sliding mode curved surface, and a non-singular terminal sliding mode controller is obtained through solving; and a nonsingular terminal sliding mode controller is used for controlling the four-degree-of-freedom marine rotary crane to move. The external disturbance of the crane system can be well inhibited by coupling measurable ship yawing and rolling disturbance and combining self-adaptive control, meanwhile, a good compensation effect is achieved for parameter uncertainty caused by reciprocating transportation in actual operation, and the stability of the system is improved. And finally, efficient trajectory tracking and swing suppression can be realized, so that a control effect is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of motion control of an underactuated crane system, and in particular to a non-singular terminal sliding mode control method and system for a marine rotary crane. Background Art

[0002] Most real physical systems in real life are nonlinear systems. There is currently no feasible general treatment method for nonlinear systems. Underactuated systems are a special type of nonlinear system. Specifically, underactuated systems usually have simpler structures than fully driven systems, which further provides the advantages of greater flexibility, lower manufacturing costs, and lower energy consumption. The widespread use of offshore cranes is of great significance to energy transportation and port development. The main goal of these cranes is to efficiently and safely transfer payloads to predetermined locations, minimizing any unwanted oscillations. Payload oscillations are often caused by the underactuated characteristics of these cranes, coupled with external disturbances such as waves and strong winds, which can be potentially dangerous and disrupt the activities of the cranes. To alleviate these challenges, the integration of automated control systems has been widely studied as a means to reduce downtime, improve operational efficiency, and enhance the overall safety of crane operations. Researchers have proposed and explored various innovative methods and technologies in this field.

[0003] Previous underactuated crane positioning and anti-swing control were mostly targeted at bridge crane systems. Even for multi-degree-of-freedom bridge cranes moving in three-dimensional space, the dynamic properties of their drivable mechanisms are still linear forces, and the dynamic characteristics are still simple and easy to control. However, when rotational torque occurs in the crane transportation task, such as the control of the ship-borne rotating crane studied in the present invention, one direction is the torque in the cantilever lifting direction, and the other direction is the rotational torque in the cantilever horizontal rotation direction. At this time, due to the participation of centrifugal motion, the system dynamic characteristics become very complicated. At the same time, due to the interference of the roll angle and yaw angle generated in the wave motion, the load swing characteristics of the crane system are more complicated. In addition, the parameter uncertainty that inevitably occurs during multiple reciprocating transportation will make the designed controller invalid. For traditional controllers, on the one hand, it is necessary to linearize the crane dynamics equations, resulting in that only the positioning effect can be achieved under normal circumstances. Once the system is far away from the equilibrium position, the swing suppression effect will not achieve the expected effect. In addition, friction resistance and wind disturbance are inevitable influencing factors in normal offshore operations. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above existing problems, the present invention is proposed. Therefore, the present invention provides a non-singular terminal sliding mode control method for a marine rotary crane to solve the problem that the load swing characteristics of the marine rotary crane become very complicated when subjected to continuous yaw and roll disturbance of the ship, and the model parameter uncertainty will occur during multiple transportations, which makes the system dynamics model more complicated, and even when the cantilever and the load are accurately positioned, the load swing cannot be quickly suppressed.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a non-singular terminal sliding mode control method for a marine rotary crane, comprising:

[0008] Obtain relevant parameters of the four-degree-of-freedom marine rotary crane and establish a first mathematical model;

[0009] Based on the first mathematical model, establishing a first equation and a second equation;

[0010] The first equation is combined with an improved non-singular fast terminal sliding mode surface to obtain a non-singular terminal sliding mode controller;

[0011] The non-singular terminal sliding mode controller is used to control the motion of the four-degree-of-freedom marine rotary crane.

[0012] As a preferred solution of the non-singular terminal sliding mode control method of the marine rotary crane of the present invention, wherein: based on the first mathematical model, establishing the first equation and the second equation includes:

[0013] The dynamic characteristics of the first mathematical model are analyzed, and according to the dynamic characteristics, the first mathematical model is divided into a drivable part and a non-drivable part to perform a first action, so as to obtain a first equation and a second equation.

[0014] As a preferred solution of the non-singular terminal sliding mode control method for a marine rotary crane according to the present invention, the improved non-singular fast terminal sliding mode surface includes:

[0015] Based on the sliding film convergence rate constraint, an improved non-singular fast terminal sliding surface is designed by combining the swing angle information and trajectory error information of the four-degree-of-freedom marine rotary crane.

[0016] As a preferred solution of the non-singular terminal sliding mode control method of the marine rotary crane of the present invention, the non-singular terminal sliding mode controller includes:

[0017] The parameters of the non-singular terminal sliding mode controller are adjusted in real time using an adaptive rate.

[0018] As a preferred solution of the non-singular terminal sliding mode control method for a marine rotary crane according to the present invention, wherein: the sliding film convergence rate constraint includes:

[0019] Designing the enhanced synovial convergence rate constraint The improved non-singular fast terminal sliding mode surface, the enhanced synovial convergence rate is expressed as:

[0020]

[0021] in, is the first-order derivative of the improved non-singular fast terminal sliding mode surface, s is the improved non-singular fast terminal sliding mode surface, β is the yaw angle of the ship, ‖s‖ is the second norm of the non-singular fast terminal sliding mode surface, M is the gain coefficient, and K is the sliding surface control law.

[0022] As a preferred solution of the non-singular terminal sliding mode control method for a marine rotary crane according to the present invention, the adaptive rate is expressed as:

[0023]

[0024] in, is the estimated value of the uncertain parameter ω1 The first-order derivative with respect to time, s is the improved non-singular fast terminal sliding surface, D f is the wind resistance of the crane, δ and σ are positive definite diagonal matrices, and η is a positive constant.

[0025] As a preferred solution of the non-singular terminal sliding mode control method of the ship rotary crane described in the present invention, the first mathematical model includes a four-degree-of-freedom ship rotary crane mathematical model and a friction feedforward compensation model.

[0026] In a second aspect, the present invention provides a system for non-singular terminal sliding mode control of a marine rotary crane, comprising:

[0027] A data acquisition and processing module, used to acquire relevant parameters of the four-degree-of-freedom marine rotary crane and establish a first mathematical model;

[0028] An equation building module, used for building a first equation and a second equation based on the first mathematical model;

[0029] A controller design module, used for solving the first equation and the improved non-singular fast terminal sliding mode surface to obtain a non-singular terminal sliding mode controller;

[0030] A motion control module is used to control the motion of the four-degree-of-freedom marine rotary crane by using the non-singular terminal sliding mode controller.

[0031] In a third aspect, the present invention provides a computing device, comprising:

[0032] Memory and processor;

[0033] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the non-singular terminal sliding mode control method of the marine rotary crane are implemented.

[0034] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, can implement the steps of the non-singular terminal sliding mode control method of the ship-mounted rotary crane.

[0035] Compared with the prior art, the present invention has the following beneficial effects: the present invention can effectively suppress the external disturbance of the crane system by coupling the measurable yaw and roll disturbance of the ship and combining it with adaptive control. At the same time, it has a good compensation effect for the parameter uncertainty caused by reciprocating transportation in actual operation, and finally can realize efficient trajectory tracking and swing suppression to achieve the control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0037] Figure 1 It is a schematic diagram of the overall flow of a non-singular terminal sliding mode control method for a marine rotary crane according to an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of the structure principle of a mathematical model of a rotary crane according to a non-singular terminal sliding mode control method for a marine rotary crane according to an embodiment of the present invention;

[0039] Figure 3 A schematic diagram of an experimental platform for a non-singular terminal sliding mode control method for a marine rotary crane according to an embodiment of the present invention;

[0040] Figure 4 It is a schematic diagram of experimental results of a non-singular terminal sliding mode control method for a marine rotary crane according to an embodiment of the present invention;

[0041] Figure 5 It is a schematic diagram of experimental results of a comparative controller output feedback controller of a non-singular terminal sliding mode control method for a marine rotary crane according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0044] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0045] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0046] At the same time, in the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0047] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] Example 1

[0049] Reference Figure 1 , as an embodiment of the present invention, provides a non-singular terminal sliding mode control method for a marine rotary crane, comprising:

[0050] S100: Obtain relevant parameters of the four-degree-of-freedom marine rotary crane and establish a first mathematical model;

[0051] Preferably, the first mathematical model includes a mathematical model of a four-degree-of-freedom marine rotary crane and a friction force feedforward compensation model;

[0052] The parameters related to the four-degree-of-freedom marine rotary crane include the mass of the cantilever and the load, the length of the cantilever and the rope, the gravity acceleration, the cantilever lift and the driving torque parameters in the horizontal rotation direction, the parameters of the friction feedforward compensation model, and the air friction parameters.

[0053] Specifically, based on the Lagrangian dynamics equation, the expression for establishing the mathematical model of the freedom ship-mounted rotary crane is:

[0054] make

[0055]

[0056] G(q)=[g1 g2 g3 g4] T

[0057] τ=[τ1 τ2 0 0] T

[0058] τ f =[τ 1f τ 2f 0 0] T

[0059] q1=θ1-α, q2=θ2-β, q3=θ3-α, q4=θ4-β

[0060]

[0061] Among them, M s (q) is the inertia matrix of the marine rotary crane system, is the centripetal-Coriolis matrix, G(q) is the gravity vector, τ is the control input vector, τ f and D are the mechanical friction and wind resistance of the marine rotating crane system, respectively. The luffing angle and rotation angle of the cantilever are θ1 and θ2, respectively. The roll angle and yaw angle of the ship are α and β, respectively. The radial swing angle and tangential swing angle of the load are θ3 and θ4, respectively. q is the new state variable of the system after coupling. q1 and q2 are the luffing angle and rotation angle of the cantilever after coupling, q3 and q4 are the radial swing angle and tangential swing angle of the load after coupling. is the first-order derivative, is its second-order derivative; M and m are the masses of the cantilever and the load, L and l are the lengths of the cantilever and the rope, g is the acceleration of gravity, and for the driving force / torque, τ1 is the driving torque in the cantilever's lifting direction, τ2 is the driving torque in the cantilever's horizontal rotation direction, τ 1f and τ 2f are the mechanical friction forces in the cantilever lifting direction and horizontal rotation direction, d ι (1,...,4) are air friction parameters;

[0062] Among them, the inertia matrix of the marine rotating crane system is as follows:

[0063]

[0064] m 12 =mL1S1S4

[0065] m 13 =-mLlS 1-3 C4

[0066] m 14 =mLlC 1-3 S4

[0067] m 21 =mL1S1S4

[0068]

[0069] m 23 =-ml 2 C3S4C4,

[0070] m 24 =ml 2 S3+mLlC1C4

[0071] m 31 =-mLlS 1-3 C4

[0072] m 32 =-ml 2 C3S4C4

[0073] m 33 =ml 2 C4 2

[0074] m 34 =0,

[0075] m 41 =mLlC 1-3 S4

[0076] m 42 =ml 2 S3+mLlC1C4

[0077] m 43 =0

[0078] m 44 =ml 2

[0079] Among them, m ij Represents matrix coordinates, i = 1, 2...4, j = 1, 2...4. Centripetal-Coriolis matrix as follows:

[0080]

[0081] c 11 =0

[0082]

[0083]

[0084] c 44 =0

[0085] where c ij , represents matrix coordinates, i=1, 2…4, j=1, 2…4.

[0086] Specifically, a friction feedforward compensation model is established, and the expression is:

[0087]

[0088] Among them, χ 1f and χ 2f is the mechanical friction of the marine rotating crane system, f 11 、f 12 、f 21 、f 22 and ε are the parameters of the friction feedforward compensation model, f 11 and f 12 The value of corresponds to the maximum static friction, f 21 and f 22is the viscous friction coefficient, ε is the static friction coefficient, and is the first-order derivative of the cantilever amplitude angle and rotation angle after coupling;

[0089] It should be noted that by comprehensively acquiring the relevant parameters of the four-degree-of-freedom marine rotary crane and establishing an accurate mathematical model based on the Lagrangian dynamic equation, the model not only covers the basic dynamic characteristics of the system such as the inertia matrix, centripetal-Coriolis matrix and gravity vector, but also takes into account external interference factors such as mechanical friction and wind resistance. In addition, by introducing the friction feedforward compensation model, the friction generated by the system drive mechanism is effectively compensated, the positioning accuracy and dynamic response capability of the system are improved, and a solid theoretical foundation is provided for the design optimization and automatic control of the marine rotary crane.

[0090] S102: Establishing a first equation and a second equation based on the first mathematical model;

[0091] Preferably, the dynamic characteristics of the first mathematical model are analyzed, and according to the dynamic characteristics, the first mathematical model is divided into a drivable part and a non-drivable part to perform a first action, so as to obtain a first equation and a second equation;

[0092] In the embodiment of the present application, the dynamic characteristics include cantilever positioning characteristics and swing angle swing characteristics, etc. The first action is matrix simplification;

[0093] In another possible embodiment, the dynamic characteristics may further include system coupling and dynamic response characteristics, and the first action may also be a processing method such as parameter separation or system decoupling.

[0094] The drivable part and the undrivable part in the first mathematical model are simplified by matrix and processed separately. The first equation is the drivable equation, and the second equation is the under-driven equation. The expression is:

[0095]

[0096] Where: Q1 = [q1 q2] T ,Q2=[q3 q4] T ,u1=[τ1τ2] T

[0097]

[0098] G1=[g1 g2] T ,G2=[g3 g4] T

[0099] τ f =η T ω=[u 1f u2f ] T =[η1 T ω1 η2 T ω2] T

[0100]

[0101] Among them, q1 and q2 are the cantilever amplitude angle and rotation angle after coupling, q3 and q4 are the radial swing angle and tangential swing angle of the load after coupling, and is the first-order derivative of the cantilever amplitude angle and rotation angle after coupling, and is the first-order derivative of the radial and tangential swing angles of the coupled load, τ 1f and τ 2f is the mechanical friction of the marine rotating crane system, f 11 、f 12 、f 21 、f 22 and ε are the parameters of the friction feedforward compensation model, f 11 and f 12 The value of corresponds to the maximum static friction, f 21 and f 22 is the viscous friction coefficient, ε is the static friction coefficient;

[0102] Transform the first equation:

[0103]

[0104] Bringing back the second equation, we get:

[0105]

[0106] It should be noted that the present invention decomposes the dynamic characteristics of the ship rotary crane into a drivable part and a non-drivable part based on the first mathematical model, and establishes the first equation and the second equation respectively through matrix simplification, which improves the accuracy and operability of the model, and also effectively reveals the influence of key dynamic characteristics such as cantilever positioning, swing angle swing, system coupling and dynamic response on the crane performance, which provides a solid theoretical basis for subsequent controller design and optimization, thereby improving the control accuracy, stability and response speed of the ship rotary crane.

[0107] S104: The first equation is solved together with the improved non-singular fast terminal sliding mode surface to obtain a non-singular terminal sliding mode controller;

[0108] Preferably, based on the sliding film convergence rate constraint, combined with the swing angle information and trajectory error information of the four-degree-of-freedom marine rotary crane, an improved non-singular fast terminal sliding mode surface is designed;

[0109] The improved non-singular fast terminal sliding surface expression is:

[0110]

[0111] λ,α,ρ,ψ,μ∈R 2×2 ,θ,τ are both positive and

[0112] The above improved non-singular fast terminal sliding mode surface expression is derived and expressed as:

[0113]

[0114] e1=[q1-q 1d q2-q 2d ] T

[0115] e2=[q3-q 3d q4-q 4d ] T

[0116] Q 1d =[q 1d q 2d ] T

[0117] Q1=[q1 q2] T

[0118] λ,α,ρ,ψ,μ∈R 2×2 ,θ,τ are both positive and

[0119] Preferably, an enhanced synovial convergence rate constraint improved non-singular fast terminal sliding mode surface is designed, and the enhanced synovial convergence rate is expressed as:

[0120]

[0121] in, is the first-order derivative of the improved non-singular fast terminal sliding mode surface, s is the improved non-singular fast terminal sliding mode surface, β is the yaw angle of the ship, ‖s‖ is the second norm of the non-singular fast terminal sliding mode surface, M is the gain coefficient, and K is the sliding surface control law;

[0122] It should be noted that β,K∈R 2×2 is a positive definite diagonal matrix and satisfies 0<p≤1, ||s|| is the second norm of the sliding surface. When the system state variable is close to the equilibrium point, this parameter can ensure a faster convergence speed. In addition, ||s|| pA small control gain is ensured to reduce the system state close to the equilibrium point when chattering is reduced. In addition, the triangular sign is used to replace the sign function to further suppress the chattering.

[0123] The simplified deformed first equation and the improved non-singular fast terminal sliding mode surface are combined to obtain the non-singular terminal sliding mode controller. The specific process is as follows:

[0124]

[0125]

[0126] β,K∈R 2×2 , p is a positive number

[0127] The final design of the non-singular terminal sliding mode controller is as follows:

[0128]

[0129] It should be noted that the present invention combines the simplified first equation with the improved non-singular fast terminal sliding mode surface to design a non-singular terminal sliding mode controller, which not only utilizes the sliding mode convergence rate constraint and the swing angle and trajectory error information of the four-degree-of-freedom ship rotary crane to optimize the performance of the sliding mode surface, but also effectively improves the convergence speed and stability of the system state when it is close to the equilibrium point by introducing strategies such as enhanced sliding film convergence rate and positive definite diagonal matrix, while significantly reducing the jitter phenomenon; this design not only improves the control accuracy and dynamic response capability of the ship rotary crane, but also enhances its anti-interference and robustness.

[0130] S106: Controlling the motion of the four-degree-of-freedom marine rotary crane using a non-singular terminal sliding mode controller;

[0131] Preferably, the parameters of the non-singular terminal sliding mode controller are adjusted in real time using an adaptive rate.

[0132] Preferably, the adaptation rate is expressed as:

[0133]

[0134] in, is the estimated value of the uncertain parameter ω1 The first-order derivative with respect to time, s is the improved non-singular fast terminal sliding surface, D f is the wind resistance of the crane, δ and σ are positive definite diagonal matrices, and η is a positive constant;

[0135] It should be noted that by introducing an adaptive rate to adjust the controller parameters in real time, the system can dynamically adapt to changes in the external environment and internal state, such as uncertain factors such as wind resistance experienced by the crane. This adaptive adjustment not only enhances the robustness of the system, but also effectively reduces unnecessary energy consumption and mechanical wear while maintaining efficient control, thereby extending the service life of the crane.

[0136] Specifically, a cantilever target tracking trajectory is planned based on the adaptive rate to verify the effect of the non-singular fast terminal sliding mode controller in suppressing the swing angle. The following reference trajectory is used to perform tracking control of the marine rotary crane system to verify the positioning and anti-swing functions, where the reference trajectory is an S-shaped trajectory:

[0137]

[0138] Where χ represents the cantilever arm starting angle q1 after coupling or the horizontal rotation angle q2 after coupling; q(χ) d , q(χ)0 and t q(χ)d They are the cantilever starting angle and rotation target angle / position, initial angle / position and arrival time.

[0139] In fact, as long as the trajectory satisfies the positioning start and end point constraints, the choice of a feasible reference trajectory is arbitrary. The following trajectories are generally available, such as step-type trajectories, S-shaped trajectories, and input shaped trajectories. However, the step-type trajectory is a discontinuous trajectory that will cause the initial output of the system actuator to be too large, affecting the control effect and being detrimental to the long-term operation of the actuator. For the input shaped trajectory, changes in the system rope length will cause the natural frequency of the vibration system to change accordingly. Then, the input shaped trajectory must be redesigned at any time before use, which is very inconvenient.

[0140] In the present invention, the trajectory shown above is selected, which has the following advantages: 1) the curve is continuous with respect to time, so the required system state can be uninterrupted; 2) the trajectory contains a sinusoidal function part with a smoothing effect; 3) the arrival time can be manually adjusted according to actual needs.

[0141] In actual application scenarios, under the condition of continuous yaw and roll disturbance of the ship, the swing characteristics of the crane are more obvious, so it is more challenging and of practical engineering significance to suppress the swing angle while achieving safe positioning tasks; therefore, the present invention mainly focuses on the trajectory tracking and swing suppression problems of marine rotary cranes. For this purpose, a mathematical model of marine rotary cranes with particle loads is first established based on the Lagrangian dynamic equation, and two equations are simplified and transformed accordingly. In order to process the state coupling variables of the entire system, a sliding surface is constructed according to four coupling state variables, and then the controller is obtained by combining the drivable variables in the simplified equation. The controller can effectively suppress external disturbances (wind resistance, mechanical friction, disturbances caused by continuous yaw and roll of the ship, etc.) and model parameter uncertainty problems; to a certain extent, the requirements of crane operation (fast positioning, effective swing elimination) are achieved. The proposed adaptive controller estimates and eliminates the interference of friction and wind, and finally tracks the S-shaped trajectory that meets the conditions to verify the advantages of the proposed controller; it is mainly manifested in the ability to quickly and effectively achieve trajectory tracking and load swing angle suppression of marine rotary cranes.

[0142] The above is a schematic scheme of a non-singular terminal sliding mode control method for a marine rotary crane of this embodiment. It should be noted that the technical scheme of the non-singular terminal sliding mode control system of the marine rotary crane and the technical scheme of the non-singular terminal sliding mode control method of the marine rotary crane belong to the same concept, and the details of the technical scheme of the non-singular terminal sliding mode control system of the marine rotary crane in this embodiment that are not described in detail can all be referred to the description of the technical scheme of the non-singular terminal sliding mode control method of the marine rotary crane.

[0143] The non-singular terminal sliding mode control system of the marine rotary crane in this embodiment includes:

[0144] A data acquisition and processing module, used to acquire relevant parameters of the four-degree-of-freedom marine rotary crane and establish a first mathematical model;

[0145] An equation building module, used for building a first equation and a second equation based on a first mathematical model;

[0146] A controller design module is used to solve the first equation and the improved non-singular fast terminal sliding mode surface to obtain a non-singular terminal sliding mode controller;

[0147] Motion control module for controlling the motion of a 4-DOF marine rotary crane using a non-singular terminal sliding mode controller.

[0148] This embodiment further provides a computing device, which is applicable to the case of non-singular terminal sliding mode control of a marine rotary crane, and includes:

[0149] A memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement the non-singular terminal sliding mode control method for a marine rotary crane as proposed in the above embodiment.

[0150] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the non-singular terminal sliding mode control method for a marine rotary crane as proposed in the above embodiment is implemented.

[0151] The storage medium proposed in this embodiment and the non-singular terminal sliding mode control method for implementing a ship-mounted rotary crane proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0152] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.

[0153] Example 2

[0154] Reference Figure 2-5 Table 1 and Table 2 are the second embodiment of the present invention. This embodiment is different from the first embodiment in that, in order to better verify and illustrate the technical effects adopted in the method of the present invention, an energy-based output feedback controller is selected for testing in this embodiment, and the test results are compared by means of scientific demonstration to verify the real effect of the method.

[0155] Reference Figure 2 and 3 In order to conduct experiments, this embodiment builds an experimental platform. Specifically, Figure 2 The hardware includes angle encoder, electronic speed regulator, motor, PC and motor power supply. The PC contains a motion control board to transmit the angle signal collected by the angle encoder. Figure 3In the equation, the luffing angle and rotation angle of the cantilever are θ1 and θ2 respectively, the roll angle and yaw angle of the ship are α and β respectively, the radial swing angle and tangential swing angle of the load are θ3 and θ4 respectively, M and m are the masses of the cantilever and the load respectively, and L and l are the length of the cantilever and the length of the suspension rope respectively;

[0156] After calculation in Matlab\Simulink, the generated code is compiled and transmitted to the electronic speed regulator through the motion control board to control the motor. Then the experimental data on the motion control board is monitored and recorded in real time through serial communication. The position signal of the drivable part comes from the encoder count; the load / hook swing angle information comes from the angle encoder, and its voltage signal is transmitted to the control board through the A / D converter. In order to accurately simulate the actual situation, we realized the rotation of the boom angle through the steel cable.

[0157] The output feedback control method is used to conduct a comparative experiment with the controller using this control method. The control formula of the output feedback controller is:

[0158]

[0159] For the output feedback controller, the parameters are:

[0160]

[0161] The amplitudes of the method used by the present method and the method used by the output feedback controller were calculated using the experimental platform constructed as described above, and the results are shown in Table 1 below;

[0162] Table 1 Comparison results of maximum amplitude experiments

[0163]

[0164] Also refer to Figure 3 and 4 It can be seen that when the positioning time is basically the same, the proposed controller can completely track the target trajectory and realize the positioning function, while the output feedback controller cannot achieve positioning in the cantilever lifting direction; and it is unable to maintain a stable positioning effect during the experiment, and the tracking and positioning process of this method is relatively smooth.

[0165] Using the proposed controller method, the arrival time of the crane in both the amplitude change and rotation directions is about 2.1 [s], while under the output feedback method, the above parameters are 4.11 [s] and 3.25 [s] respectively. Compared with the proposed controller, the positioning time of the output feedback in the amplitude start and rotation directions increased by 48.9% and 35.4% respectively. In terms of swing suppression, the amplitude of the load caused by the controller of this method is not large and will not exceed 3.2 [deg], while the amplitude of the load caused by the controller of the traditional output feedback method is too large, not less than 2 [deg] and the maximum is nearly 4.85 [deg]. Compared with the output feedback method, the maximum amplitudes of q3 and q4 are reduced by 27.5% and 40% respectively.

[0166] Moreover, the swing of this method can be completely eliminated within 2 to 4 seconds after the positioning of the drivable mechanism is completed, while the suppression effect of the traditional method is particularly poor. After experiencing multiple intense shocks, there is still residual swing until 13 seconds later. The force of this method is controlled between -10 [N] and 20 [N], but the force of the output feedback controller is extremely unstable and has exceeded 30 [N]. Therefore, the swing suppression efficiency of this method is extremely high, and the positioning is accurate, without overshoot and steady-state error.

[0167] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A non-singular terminal sliding mode control method for a marine rotary crane, characterized in that: include: Obtain relevant parameters of the four-degree-of-freedom marine rotary crane and establish a first mathematical model; Based on the first mathematical model, establishing a first equation and a second equation; The equation is combined with an improved non-singular fast terminal sliding mode surface to obtain a non-singular terminal sliding mode controller; The non-singular terminal sliding mode controller is used to control the motion of the four-degree-of-freedom marine rotary crane.

2. The non-singular terminal sliding mode control method for a marine rotary crane according to claim 1, characterized in that: Based on the first mathematical model, establishing the first equation and the second equation includes: The dynamic characteristics of the first mathematical model are analyzed, and according to the dynamic characteristics, the first mathematical model is divided into a drivable part and a non-drivable part to perform a first action, so as to obtain a first equation and a second equation.

3. The non-singular terminal sliding mode control method for a marine rotary crane according to claim 1 or 2, characterized in that: The improved non-singular fast terminal sliding surface includes: Based on the sliding film convergence rate constraint, an improved non-singular fast terminal sliding surface is designed in combination with the swing angle information and trajectory error information of the four-degree-of-freedom marine rotary crane.

4. The non-singular terminal sliding mode control method for a marine rotary crane according to claim 3, characterized in that: The non-singular terminal sliding mode controller includes, The parameters of the non-singular terminal sliding mode controller are adjusted in real time using an adaptive rate.

5. The non-singular terminal sliding mode control method for a marine rotary crane according to claim 4, characterized in that: The synovial convergence rate constraints include, Designing the enhanced synovial convergence rate constraint The improved non-singular fast terminal sliding mode surface, the enhanced synovial convergence rate is expressed as: in, is the first-order derivative of the improved non-singular fast terminal sliding mode surface, s is the improved non-singular fast terminal sliding mode surface, β is the yaw angle of the ship, ‖s‖ is the second norm of the non-singular fast terminal sliding mode surface, M is the gain coefficient, and K is the sliding surface control law.

6. The non-singular terminal sliding mode control method for a marine rotary crane according to claim 5, characterized in that: The adaptation rate is expressed as: in, is the estimated value of the uncertain parameter ω1 The first-order derivative with respect to time, s is the improved non-singular fast terminal sliding surface, D f is the wind resistance of the crane, δ and σ are positive definite diagonal matrices, and η is a positive constant.

7. The non-singular terminal sliding mode control method for a marine rotary crane according to claim 1, characterized in that: The first mathematical model includes a mathematical model of a four-degree-of-freedom marine rotary crane and a friction feedforward compensation model.

8. A system for non-singular terminal sliding mode control of a marine rotary crane, characterized in that: include, A data acquisition and processing module, used to acquire relevant parameters of the four-degree-of-freedom marine rotary crane and establish a first mathematical model; An equation building module, used for building a first equation and a second equation based on the first mathematical model; A controller design module, used for solving the first equation and the improved non-singular fast terminal sliding mode surface to obtain a non-singular terminal sliding mode controller; A motion control module is used to control the motion of the four-degree-of-freedom marine rotary crane by using the non-singular terminal sliding mode controller.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the non-singular terminal sliding mode control method for a marine rotary crane according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the non-singular terminal sliding mode control method for a marine rotary crane according to any one of claims 1 to 7.

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