Large-aperture space telescope fixed time sliding mode anti-interference control method and related equipment

Abstract

The invention discloses a large-aperture space telescope fixed time sliding mode anti-interference control method and related equipment. The method comprises the following steps: establishing a double-inertia system dynamic model containing motor end and load end dynamic parameters and total disturbance; constructing a fixed time expansion state observer based on the model, and estimating the total disturbance of the motor end; converting the model into a generalized all-wheel-drive system model through an all-wheel-drive system theory, designing an expected closed-loop system model, and identifying the expected closed-loop system model by using a neural network to obtain a preset performance function; a motor end angle position tracking error is obtained, and a speed ring reference speed instruction is generated after preset performance function constraint transformation; defining an angular velocity tracking error based on the instruction, constructing a fixed time terminal integral sliding mode control surface and designing a sliding mode reaching law; and finally, synthesizing a motor control law and applying the motor control law to a driving motor to complete anti-interference control. The problems that a traditional preset performance function is single in form, an observer cannot converge at fixed time, and a traditional control mode is difficult to suppress vibration, high in cost and limited are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of large-aperture space telescope control, and particularly relates to a large-aperture space telescope fixed-time sliding mode disturbance rejection control method and related equipment. BACKGROUND

[0002] With the progress of science and technology and the increasingly fierce space competition, space situation awareness has significantly improved the strategic value of national security and economic development. As a key component of the space situation awareness system, space telescopes have the unique advantage of being unaffected by the atmosphere and can perform wide-area monitoring tasks around the clock. Under the joint promotion of increasing demand for exploration and improved carrying capacity, increasing the aperture of telescopes to improve resolution has become a technically feasible path. Although current on-orbit telescopes are mainly small-aperture, large-aperture space telescopes have gradually been applied and will play an increasingly important role in future space technology development. One of the core technologies for achieving high-performance applications is a high-precision, high-reliability control system. By controlling the two-degree-of-freedom motion of the telescope's elevation and azimuth axes, full-range monitoring, large-scale search and capture, accurate pointing, and stable tracking of space targets can be effectively completed.

[0003] Compared with ground-based large-aperture telescopes, large-aperture space telescopes must adopt an extremely lightweight design due to the constraints of carrying capacity. This results in reduced system stiffness, combined with the often-equipped large flexible sunshade and other accessories, which makes the overall structure have a low resonant frequency, and the end accessories are easily induced to vibrate. Such structural flexibility not only severely restricts the control performance of the system, but also may cause safety hazards. In addition, the structural constraints of large-aperture space telescopes usually only allow the installation of position sensors on the motor side, forming a typical partially state feedback nonlinear high-order system. At the same time, the system also faces multiple complex disturbances, including nonlinear friction, model uncertainty, installed unbalanced moments, vacuum and microgravity environmental effects, and cable winding moments. The combined effects of these structural flexibility, measurement limitations, and environmental disturbance factors limit the control accuracy improvement and closed-loop bandwidth expansion of large-aperture space telescopes, and even threaten the stability of the system. Although the closed-loop control technology of ground-based large-aperture telescopes is relatively mature, the high-precision stable control technology for space large-aperture telescopes under severe constraints and complex disturbances is still insufficient.

[0004] In the field of vibration and resonance suppression, wave traps, filters, feedforward control and preset performance control are currently widely used technical means. Preset performance control has been widely used in vibration suppression due to its relatively simple structure. Its core idea is to dynamically impose clear constraint boundaries on the tracking error of the system by introducing a preset performance function, and to convert the constrained error control problem into an unconstrained optimization problem with the help of differential homeomorphism mapping. However, one limitation of the existing preset performance control method is that the design of the performance function is often relatively basic and fails to effectively integrate and reflect the structural characteristics of the controlled system. This single form of performance function design limits its constraint accuracy and ability to adapt to complex working conditions, making it difficult to maximize the potential of preset performance control. Especially noteworthy is that in many actual vibration suppression scenarios, direct state measurement at the load end is often difficult to obtain due to the lack of sensors. This constraint condition poses a challenge to accurately depicting the load dynamics and designing the corresponding performance function. In the high-precision control of large-aperture space telescopes, although the traditional finite-time stabilization method can improve the dynamic performance, its convergence time is heavily dependent on the initial conditions, and existing research generally ignores the potential threat of transient performance to system safety. Excessive control torque can excite flexible resonance when accelerating error convergence, leading to increased end vibration and even structural damage.

[0005] In summary, the existing technology has the following shortcomings: the traditional preset performance function is single in form, which severely limits its constraint accuracy and ability to adapt to complex working conditions, making it difficult to maximize the potential of preset performance control. The convergence time of the traditional observer is largely dependent on the initial error, and it cannot achieve fixed-time convergence. Traditional control methods such as PID control cannot achieve end vibration suppression, and the need for additional sensors to obtain the state of the end load increases the cost and is limited by the structure. SUMMARY

[0006] To solve the problems in the prior art, the present application provides a large-aperture space telescope fixed-time sliding mode disturbance rejection control method and related equipment, which aims to solve the problems of the prior art that the traditional preset performance function is single in form, severely limiting the constraint accuracy and adaptability to complex working conditions, the traditional observer cannot achieve fixed-time convergence, and traditional control methods such as PID control cannot suppress end vibration and require additional sensors to increase cost and be limited by structure.

[0007] To solve the above technical problems, the present application is implemented by the following technical solutions: According to a first aspect of the present application, a large-aperture space telescope fixed-time sliding mode disturbance rejection control method is provided, comprising: establishing a double-inertia system dynamics model of a large-aperture space telescope, the double-inertia system dynamics model including the dynamics parameters of the motor end and the load end and the total disturbance acting on the motor end; Based on the double-inertia system dynamics model, a fixed-time extended state observer is constructed, the total disturbance at the motor end of the double-inertia system is estimated by using the fixed-time extended state observer, and a total disturbance estimation value at the motor end is obtained; The double-inertia system dynamics model is converted into a generalized all-wheel drive system model through the all-wheel drive system theory, an expected closed-loop system model is designed for the generalized all-wheel drive system model, and the expected closed-loop system model is identified by using a neural network to obtain a preset performance function with system structure characteristics; An angular position tracking error at the motor end is obtained, and the angular position tracking error at the motor end is constrained and transformed by using the preset performance function; based on the transformed angular position tracking error at the motor end, a reference speed instruction of a speed loop is generated; Based on the reference speed instruction, an angular velocity tracking error at the motor end is defined, and a fixed-time terminal integral sliding mode control surface is constructed based on the angular velocity tracking error at the motor end, and a fixed-time convergent sliding mode reaching law is designed; According to the sliding mode control surface, the sliding mode reaching law, the double-inertia system dynamics model, and the total disturbance estimation value at the motor end, a final motor control law is synthesized, and the motor control law is applied to the driving motor of the space telescope to complete the disturbance rejection control.

[0008] In a possible implementation manner of the first aspect, the double-inertia system dynamics model specifically includes:

[0009] In the formula, ; represents an angular position at the motor end; represents an angular velocity at the motor end; represents an angular position at the load end; represents an angular velocity at the load end; represents a number of pole pairs of the motor; represents a number of flux linkages of the permanent magnet; represents an equivalent motor rotational inertia; represents an input of the double-inertia system dynamics model; represents a stiffness of an equivalent shaft; represents an equivalent load rotational inertia; represents a viscous damping coefficient at the load end; , , represents a total disturbance at the motor end; represents a nonlinear disturbance, including nonlinear friction and wire winding torque; represents an internal disturbance including uncertainties of the double-inertia system dynamics model; viscous damping coefficient representing the motor side.

[0010] In a possible implementation manner of the first aspect, the fixed-time extended state observer, in particular,

[0011] wherein, an estimated value of the angular position of the motor side; an estimated value of the angular velocity of the motor side; an estimated value of the angular position of the load side; an estimated value of the total disturbance of the motor side; and represent an observer first parameter and an observer second parameter respectively, ; and are normal numbers; represent an observer bandwidth; represent an observer gain, ; an estimated error of the estimated value of the angular position of the motor side.

[0012] In a possible implementation manner of the first aspect, the generalized full-drive system model, in particular,

[0013]

[0014]

[0015] wherein, represent an input of the generalized full-drive system model; represent a nonsingular transformation matrix; represent a controllability matrix of the double-inertia system state space equation; characteristic polynomial coefficients, .

[0016] In a possible implementation manner of the first aspect, the expected closed-loop system model, in particular,

[0017] wherein, represent a reference input of the generalized full-drive system model; represent a state feedback gain, .

[0018] In a possible implementation manner of the first aspect, the preset performance function, in particular,

[0019]

[0020] In the formula, Represents the default performance function; This represents the result of the neural network identifying the desired closed-loop system model; Represents the number of neuron nodes; Reference input representing the angular position of the motor end; Represents steady-state control accuracy; Representing the The connection weights between each neuron node and its output; Representing the Radial basis functions of each neuron node Represents the center of the radial basis functions. Represents the width of the radial basis functions; This represents the angular position tracking error at the motor end.

[0021] In one possible implementation of the first aspect, the fixed-time terminal integral sliding mode control surface specifically comprises:

[0022] In the formula, Represents the fixed-time terminal integral sliding mode control surface; Represents the first control gain; Represents the second control gain; Represents the first sliding mode control parameter; This represents the second sliding mode control parameter; This represents the angular velocity tracking error at the motor end; The sliding mode reaching law is specifically as follows:

[0023] In the formula, Represents the gain of the first reaching law; Represents the gain of the second reaching law; This represents the control parameters of the first sliding mode reaching law; This represents the control parameters of the second sliding mode reaching law; This represents the conversion gain.

[0024] In one possible implementation of the first aspect, the motor control law is specifically as follows: .

[0025] According to a second aspect of the present application, a computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the fixed-time sliding mode disturbance rejection control method for a large aperture space telescope when executing the computer program.

[0026] According to a third aspect of the present application, a computer readable storage medium stores a computer program, wherein the computer program is executed by a processor to implement the fixed-time sliding mode disturbance rejection control method for a large aperture space telescope.

[0027] Compared with the prior art, the present application has at least the following beneficial effects: The fixed-time sliding mode disturbance rejection control method for a large aperture space telescope provided by the present application fuses full-drive system theory and neural network technology to construct an adaptive preset performance function with structural dependence characteristics, which can effectively approximate unmodeled dynamics at the load end and integrate system structural information into error constraint boundary design, overcoming the defects of single form of traditional preset performance function and insufficient constraint accuracy. Thus, when dynamically constraining tracking error, the system physical nature can be better fitted, the adaptability to complex working conditions can be improved, and the preset performance control effect can be maximized. The fixed-time extended state observer used can bound the estimation of total disturbance, and the upper bound of its convergence time is only determined by the controller parameters, which is irrelevant to the initial error of the system, overcoming the limitation that the convergence time of the traditional observer seriously depends on the initial state, ensuring that disturbance estimation can be achieved within a fixed time determined in advance under any initial condition. By constructing a fixed-time terminal integral sliding mode control surface and designing a fixed-time convergent sliding mode reaching law, the system state can quickly converge within a fixed time independent of the initial condition. At the same time, the strict constraint of the preset performance function on the tracking error effectively suppresses transient overshoot and flexible resonance, avoiding excessive control torque excitation-induced end vibration. Under the full-drive system framework, the neural network is used to identify the dynamics at the load end, and the end state reconstruction can be achieved without additional load end sensors, which suppresses the end load vibration while avoiding the cost increase and structural limitation problems caused by the dependence on additional sensors in traditional control methods (such as PID). Through the triple synergy of structural characteristic function, fixed-time control, and disturbance active suppression, the comprehensive influence of system flexibility, measurement limitations, and complex environmental disturbances is effectively overcome, the closed-loop control bandwidth is improved, and the on-orbit safety of the large aperture space telescope is ensured.

[0028] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are referred to. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application, the drawings needed to be used in the specific embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0030] Figure 1 A flow chart of a fixed-time sliding mode disturbance rejection control method for a large-aperture space telescope according to the present application; Figure 2 A structural schematic diagram of a large-aperture space telescope; Figure 3 A dual-inertia system model; Figure 4 A control structure block diagram; Figure 5 A comparison of motor end angle step responses under the present application and conventional control; Figure 6 A comparison of load end angle step responses under the present application and conventional control. DETAILED DESCRIPTION

[0031] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.

[0032] As shown in Figure 1 , the present embodiment provides a fixed-time sliding mode disturbance rejection control method for a large-aperture space telescope, which specifically includes the following steps: S1, a dual-inertia system dynamics model of the large-aperture space telescope is established, the dual-inertia system dynamics model including dynamics parameters of a motor end and a load end and total disturbances acting on the motor end.

[0033] Specifically, a structural schematic diagram of the large-aperture space telescope is as shown in Figure 2 , according to the structure of the large-aperture space telescope, the large-aperture space telescope is equivalent to a dual-inertia system, as shown in Figure 3 . In Figure 3 , the equivalent motor rotational inertia and the equivalent load rotational inertia are connected by an equivalent shaft with a stiffness of , the output torque of the motor is , , the number of pole pairs of the motor is is the flux linkage of the permanent magnet, and and are the viscous damping coefficients of the motor side and the load side, respectively, and are the angular position of the motor side and the angular velocity of the motor side, respectively, and are the angular position of the load side and the angular velocity of the load side, respectively. According to Figure 3 , the state is selected, and the following dynamic model of the dual-inertia system is obtained: (1) Considering the influence of disturbance and model uncertainty, (1) can be rewritten as: (2) where is the total disturbance acting on the motor side, represents the nonlinear disturbance, mainly including nonlinear friction and wire winding torque; represents the internal disturbance including the uncertainty of the dynamic model of the dual-inertia system; represents the input of the dynamic model of the dual-inertia system.

[0034] S2, based on the dynamic model of the dual-inertia system, a fixed-time extended state observer is constructed, and the total disturbance of the motor side of the dual-inertia system is estimated by using the fixed-time extended state observer to obtain the total disturbance estimation value of the motor side.

[0035] Specifically, based on the established dynamic model formula (1) of the dual-inertia system, the estimation error of the angular position estimation value of the motor side is defined as , and the following fixed-time extended state observer is designed: (3) where: represents the angular position estimation value of the motor side; represents the angular velocity estimation value of the motor side; represents the angular position estimation value of the load side; represents the total disturbance estimation value of the motor side; that is, , , are the estimation values of the state , and the total disturbance of the motor side, respectively; represents the bandwidth of the observer; and represent the first parameter of the observer and the second parameter of the observer, respectively, and , , and is a positive constant; represents the observer gain, , The selection of needs to make the matrix is a Hurwitz matrix.

[0036] According to formula (3), the estimation error of the estimated value of the angular velocity of the motor end , the estimation error of the estimated value of the angular position of the load end The observation error equation can be obtained: (4) S3, the double inertia system dynamics model is converted into a generalized full drive system model by full drive system theory, an expected closed loop system model is designed for the generalized full drive system model, and a neural network is used to identify the expected closed loop system model to obtain a preset performance function with system structure characteristics.

[0037] In this embodiment, the neural network adopts an RBF neural network.

[0038] Specifically, the double inertia system dynamics model is converted into a generalized full drive system model by full drive system theory, as follows: Since the end load state of the double inertia system cannot be obtained through a sensor, a non-singular transformation matrix is constructed based on the characteristic polynomial of formula (2), as follows.

[0039] (5) Wherein, the non-singular transformation matrix , are the characteristic polynomial coefficients, is the controllability matrix of the state space equation of the double inertia system.

[0040] Based on the non-singular transformation of formula (5), the inertia system dynamics model is converted into a generalized full drive system model: (6) In the formula, represents the input of the generalized full drive system model.

[0041] Specifically, an expected closed loop system model is designed for the generalized full drive system model, as follows: For formula (6), a pole placement controller is designed to make the end load output not vibrate, and the following expected closed loop system model is obtained: (7) In the formula, represents the reference input of the generalized full drive system model; is the state feedback gain.

[0042] Specifically, the neural network is used to identify the expected closed-loop system model, and a preset performance function with system structure characteristics is obtained, as follows: According to the input and output data of formula (7), the RBF neural network is used to identify the expected closed-loop system model: (8) wherein, represents the result of identifying the expected closed-loop system model by the neural network; represents the connection weight between the th neuron node and the output, represents the radial basis function of the th neuron node, represents the center of the radial basis function, represents the width of the radial basis function, represents the reference input of the angular position of the motor end.

[0043] Based on the output prediction of the RBF neural network, a novel preset performance function with structure characteristics is designed as follows : (9) wherein, represents the steady-state control accuracy; represents the number of neuron nodes.

[0044] Derivation of formula (9) can obtain: (10) wherein, .

[0045] S4, the angular position tracking error of the motor end is obtained, and the angular position tracking error of the motor end is constrained and transformed by using the preset performance function; based on the transformed angular position tracking error of the motor end, the reference speed command of the speed loop is generated.

[0046] Specifically, in combination with the preset performance control, the angular position tracking error of the motor end is defined as , and the variable is defined, and then the preset performance function is constrained based on the following relationship: (11) wherein, is the lower boundary of the overshoot; is the upper boundary of the overshoot.

[0047] In order to facilitate the controller design, a differential homeomorphism transformation is adopted to convert the constrained problem into an unconstrained problem: (12) wherein, is the transformed motor end angular position tracking error.

[0048] For the position loop, a proportional control is adopted, and thus, (13) wherein, is the reference speed command of the speed loop; is a proportional control factor.

[0049] S5, based on the reference speed command, defining the angular speed tracking error of the motor end, based on the angular speed tracking error of the motor end, constructing a fixed-time terminal integral sliding mode control surface, and designing a fixed-time convergent sliding mode reaching law.

[0050] Specifically, based on formula (13), the angular speed tracking error of the motor end is defined as , and the fixed-time terminal integral sliding mode control surface is designed as : (14) wherein, represents a first control gain; represents a second control gain; represents a first sliding mode control parameter; represents a second sliding mode control parameter.

[0051] The fixed-time convergent sliding mode reaching law is designed as : (15) wherein, represents a first reaching law gain; represents a second reaching law gain; represents a first sliding mode reaching law control parameter; represents a second sliding mode reaching law control parameter; represents a conversion gain.

[0052] According to the sliding mode control surface, the sliding mode reaching law, the dual-inertia system dynamics model, and the total disturbance estimation value of the motor end, a final motor control law is synthesized, and the motor control law is applied to the drive motor of the space telescope to complete the disturbance rejection control.

[0053] Specifically, based on formula (14), formula (15), and formula (2), the motor control law can be obtained as .

[0054] The overall control structure block diagram is shown in Figure 4 .

[0055] Embodiment This embodiment illustrates the implementation process of the present application in combination with the speed control problem of a double inertia system, and the specific parameters are as follows: 1. The specific angular position reference signal is a unit step signal, and the specific total disturbance signal at the motor end is: .

[0056] 2. The specific parameters of the dynamic model of the double inertia system are: , , , , , , .

[0057] 3. The specific parameter design of the fixed-time extended state observer is: , , , , .

[0058] 4. The specific preset performance function of the RBF neural network design is: based on the expected closed-loop system model after pole placement, the network is trained using historical input and output data, the width of the radial basis function is selected as 0.1, the kernel function center is selected by the K-Means method, the maximum number of iterations is 100 times, the number of hidden layer nodes is 20, and the steady-state control accuracy .

[0059] 5. The specific controller parameter design is: , , , .

[0060] As can be seen from Figure 5 and Figure 6 , by comparing with the conventional performance function, it can be found that the performance function designed in combination with the system dynamic characteristics has a vibration suppression effect at the load end that is obviously superior to the conventional performance function, and the designed fixed-time terminal integral sliding mode control can effectively improve the end load control accuracy.

[0061] In another embodiment of the present application, a computer device is provided, which comprises a processor and a memory, the memory is configured to store a computer program, the computer program comprises program instructions, and the processor is configured to execute the program instructions stored in the computer storage medium. The processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, and are suitable for implementing one or more instructions, and are particularly suitable for loading and executing one or more instructions in the computer storage medium to implement a corresponding method process or a corresponding function; the processor in the embodiments of the present application can be used for the operation of the large aperture space telescope fixed time sliding mode disturbance control method.

[0062] In another embodiment of the present application, the present application further provides a storage medium, specifically a computer readable storage medium (Memory), which is a memory device in the computer device, and is configured to store programs and data. It can be understood that the computer readable storage medium herein can include the built-in storage medium in the computer device, and of course can also include the expansion storage medium supported by the computer device. The computer readable storage medium provides a storage space, and the storage space stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and the instructions can be one or more computer programs (including program codes). It should be noted that the computer readable storage medium herein can be a high-speed RAM memory, or a non-volatile memory such as at least one disk memory. One or more instructions stored in the computer readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the large aperture space telescope fixed time sliding mode disturbance control method in the above embodiments.

[0063] Those skilled in the art will appreciate that embodiments of the present application can be readily used as a method, a system or a computer program product. Accordingly, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code thereon.

[0064] The present application is described in reference to the flowchart illustrations and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks.

[0065] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks.

[0066] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks.

[0067] The application further provides a computer program product, which is used for executing the large-aperture space telescope fixed-time sliding mode disturbance rejection control method described above. Since the computer program product provided by the application belongs to the same inventive concept as the large-aperture space telescope fixed-time sliding mode disturbance rejection control method described above, the computer program product provided by the application has all the advantages of the large-aperture space telescope fixed-time sliding mode disturbance rejection control method described above, and thus the beneficial effects of the computer program product provided by the application are not described one by one here.

[0068] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0069] Finally, it should be noted that: the above-described embodiments are only specific embodiments of the present application, which are used to illustrate the technical solutions of the present application, but not to limit them, the protection scope of the present application is not limited thereto, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any skilled person in the art can modify or easily think of changes to the technical solutions recorded in the foregoing embodiments within the technical range disclosed by the present application, or make equivalent replacement to some technical features; and these modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and all should be covered in the protection scope of the present application.

Claims

1. A method for disturbance rejection control of a fixed-time sliding mode in a large-aperture space telescope, characterized in that, include: A dynamic model of a dual-inertial system for a large-aperture space telescope is established. The dynamic model of the dual-inertial system includes the dynamic parameters of the motor end and the load end, as well as the total disturbance acting on the motor end. Based on the dynamic model of the dual-inertia system, a fixed-time extended state observer is constructed. The fixed-time extended state observer is used to estimate the total disturbance at the motor end of the dual-inertia system, and the estimated value of the total disturbance at the motor end is obtained. The dynamic model of the dual-inertia system is transformed into a generalized all-drive system model using the theory of all-drive systems. A desired closed-loop system model is designed for the generalized all-drive system model, and a neural network is used to identify the desired closed-loop system model to obtain a preset performance function with system structural characteristics. The angular position tracking error at the motor end is obtained, and the preset performance function is used to constrain and transform the angular position tracking error at the motor end. Based on the angular position tracking error at the transformed motor end, a reference speed command for the speed loop is generated; Based on the reference speed command, the angular velocity tracking error at the motor end is defined. Based on the angular velocity tracking error at the motor end, a fixed-time terminal integral sliding mode control surface is constructed, and a sliding mode convergence law with fixed-time convergence is designed. Based on the sliding mode control surface, the sliding mode approach law, the dual-inertia system dynamics model, and the total disturbance estimate at the motor end, the final motor control law is synthesized and applied to the drive motor of the space telescope to complete the disturbance rejection control.

2. The method for fixed-time sliding mode disturbance rejection control of a large-aperture space telescope according to claim 1, characterized in that, The dynamic model of the dual-inertia system is as follows: In the formula, ; This represents the angular position of the motor end; Represents the angular velocity at the motor end; Represents the angular position of the load end; Represents the angular velocity at the load end; Represents the number of pole pairs of the motor; The number of flux linkages in a permanent magnet; Represents the equivalent moment of inertia of the motor; This represents the input to the dynamic model of a two-inertia system. Represents the stiffness of the equivalent shaft; Represents the equivalent load rotational inertia; Represents the viscous damping coefficient at the load end; , , This represents the total disturbance at the motor end; This represents nonlinear disturbances, including nonlinear friction and wire winding torque; Internal disturbances, including uncertainties in the dynamic model of a dual-inertia system, are represented. This represents the viscous damping coefficient at the motor end.

3. The method for fixed-time sliding mode disturbance rejection control of a large-aperture space telescope according to claim 2, characterized in that, The fixed-time extended state observer is specifically: In the formula, Represents the estimated angular position of the motor end; This represents the estimated angular velocity at the motor end. Represents the estimated angular position of the load end; This represents the estimated total disturbance at the motor end; and These represent the first and second parameters of the observer, respectively. ; and It is a positive number; Represents the observer bandwidth; Represents the observer gain. ; This represents the estimation error of the estimated angular position at the motor end.

4. The method for fixed-time sliding mode disturbance rejection control of a large-aperture space telescope according to claim 3, characterized in that, The generalized all-wheel drive system model is specifically as follows: In the formula, The input representing the generalized all-wheel drive system model; Represents a non-singular transformation matrix; The controllability matrix represents the state-space equations of a two-inertia system; Characteristic polynomial coefficients, .

5. The method for fixed-time sliding mode disturbance rejection control of a large-aperture space telescope according to claim 4, characterized in that, The desired closed-loop system model is specifically as follows: In the formula, The reference input representing the generalized all-wheel drive system model; Represents the state feedback gain. .

6. The method for fixed-time sliding mode disturbance rejection control of a large-aperture space telescope according to claim 5, characterized in that, The preset performance function is specifically as follows: In the formula, Represents the default performance function; This represents the result of the neural network identifying the desired closed-loop system model; Represents the number of neuron nodes; Reference input representing the angular position of the motor end; Represents steady-state control accuracy; Representing the The connection weights between each neuron node and its output; Representing the Radial basis functions of each neuron node Represents the center of the radial basis functions. Represents the width of the radial basis functions; This represents the angular position tracking error at the motor end.

7. The method for fixed-time sliding mode disturbance rejection control of a large-aperture space telescope according to claim 6, characterized in that, The fixed-time terminal integral sliding mode control surface is specifically as follows: In the formula, Represents the fixed-time terminal integral sliding mode control surface; Represents the first control gain; Represents the second control gain; Represents the first sliding mode control parameter; This represents the second sliding mode control parameter; This represents the angular velocity tracking error at the motor end; The sliding mode reaching law is specifically as follows: In the formula, Represents the gain of the first reaching law; Represents the gain of the second reaching law; This represents the control parameters of the first sliding mode reaching law; This represents the control parameters of the second sliding mode reaching law; This represents the conversion gain.

8. The method for fixed-time sliding mode disturbance rejection control of a large-aperture space telescope according to claim 7, characterized in that, The motor control law is as follows: 。 9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements a fixed-time sliding mode disturbance rejection control method for a large-aperture space telescope as described in any one of claims 1 to 8.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements a fixed-time sliding mode disturbance rejection control method for a large-aperture space telescope as described in any one of claims 1 to 8.

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