Fixed-point vibration absorption method based on distributed magnetic suspension flywheel axial momentum exchange

Abstract

The invention relates to the technical field of aerospace, in particular to a fixed-point vibration absorption method based on distributed magnetic suspension flywheel axial momentum exchange. The method comprises the following steps: establishing a magnetic suspension rotor dynamical model comprising axial translation and axial rotation of a rotor; determining a magnetic suspension flywheel group control quantity model according to the magnetic suspension rotor dynamic model; determining a star active control force and a star active control moment according to the magnetic suspension flywheel group control quantity model and the star dynamic model; under the constraint of the star active control force and the star active control torque, determining a force / torque distribution matrix of the magnetic suspension flywheel group; according to the force / torque distribution array of the magnetic suspension flywheel group, determining the axial vibration force and the torque action quantity of each flywheel; and on the basis of the magnetic suspension rotor dynamic model, according to the axial vibration force and the torque action quantity of each flywheel, determining a driving current to suppress vibration. According to the scheme, load precision stability and ultra-static performance can be achieved.

Description

Technical Field

[0001] The invention relates to the field of aerospace technology, and in particular to a fixed-point vibration absorption method based on axial momentum exchange of a distributed magnetic suspension flywheel. Background Art

[0002] With the rapid development of aerospace technology, the payload performance of application satellites such as high-resolution optical observation, laser communication, and scientific experimental satellites such as space astronomical detection has been significantly improved. They are extremely sensitive to stellar micro-vibrations. Therefore, the payload has put forward high requirements on the attitude accuracy, stability, vibration magnitude at the payload, and line of sight jitter caused by stellar vibration of the satellite platform. For example, since the Webb telescope needs to stare at a specific sky area for a long time, payload jitter may cause a decrease in imaging quality. Therefore, suppressing on-board micro-vibrations is a necessary condition for achieving ultra-quiet satellite platforms and ensuring the performance of payloads and sensors.

[0003] In view of the payload's requirements for precise and ultra-quiet attitude, the existing satellites use inertial attitude actuators such as mechanical flywheels or control torque gyroscopes, which can only control micro-vibrations within a bandwidth range (generally not exceeding 10Hz). However, broadband micro-vibrations ranging from 0 to several thousand Hz are distributed on the satellite, and the micro-vibration response of the payload affects the payload performance. Therefore, it is necessary to strengthen the attitude control system's ability to suppress medium and high frequency micro-vibrations of the satellite platform. To this end, the present invention provides a fixed-point vibration absorption method based on axial momentum exchange of a distributed magnetic levitation flywheel to achieve precise and ultra-quiet performance of the payload. Summary of the invention

[0004] The embodiment of the present invention provides a fixed-point vibration absorption method based on axial momentum exchange of a distributed magnetic levitation flywheel, which can achieve precise load stability and ultra-quiet performance.

[0005] In a first aspect, an embodiment of the present invention provides a fixed-point vibration absorption method based on axial momentum exchange of a distributed magnetic levitation flywheel, comprising:

[0006] Establish a magnetically suspended rotor dynamics model including the rotor's axial translation and axial rotation;

[0007] Determining a control quantity model of a magnetic suspension flywheel group according to the magnetic suspension rotor dynamics model;

[0008] Determine the active control force and active control torque of the star according to the magnetic levitation flywheel group control quantity model and the star dynamics model;

[0009] Under the constraints of the active control force of the star body and the active control torque of the star body, determining the force / torque distribution matrix of the magnetic suspension flywheel group;

[0010] Determining the axial vibration force and torque action of each flywheel according to the force / torque distribution matrix of the magnetic suspension flywheel group;

[0011] On the basis of the magnetic suspension rotor dynamics model, the driving current is determined to suppress the vibration according to the axial vibration force and torque action of each flywheel.

[0012] In a second aspect, an embodiment of the present invention further provides a fixed-point vibration absorbing device based on axial momentum exchange of a distributed magnetic suspension flywheel, comprising:

[0013] The first processing module is used to establish a magnetic suspension rotor dynamics model including the rotor axial translation and axial rotation;

[0014] A second processing module is used to determine a control quantity model of a magnetic suspension flywheel group according to the magnetic suspension rotor dynamics model;

[0015] A third processing module is used to determine the active control force and active control torque of the star according to the magnetic suspension flywheel group control quantity model and the star dynamics model;

[0016] A fourth processing module, used for determining a force / torque distribution matrix of a magnetic suspension flywheel group under the constraints of the active control force of the star body and the active control torque of the star body;

[0017] A fifth processing module, used to determine the axial vibration force and torque action of each flywheel according to the force / torque distribution matrix of the magnetic suspension flywheel group;

[0018] The sixth processing module is used to determine the driving current to suppress vibration based on the magnetic suspension rotor dynamics model and the axial vibration force and torque action of each flywheel.

[0019] In a third aspect, an embodiment of this specification further provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method described in any embodiment of the present invention is implemented.

[0020] In a fourth aspect, the embodiments of this specification further provide a computer-readable storage medium on which a computer program is stored. When the computer program is executed in a computer, the computer is caused to execute the method described in any embodiment of the present invention.

[0021] The embodiment of the present invention provides a fixed-point vibration absorption method and device based on the axial momentum exchange of a distributed magnetic suspension flywheel, which generates the force and torque of satellite micro-vibration control by actively exciting the magnetic suspension rotor group, and exchanges controlled momentum and angular momentum with the satellite body, so that the vibration at any point can be actively suppressed, and the vibration response from any fixed point such as the load is absorbed into the magnetic suspension rotor, similar to pumping water to another reservoir through a water pump, so as to achieve the "pumping" effect of micro-vibration energy. It can be expected that this method will have extremely high vibration control efficiency and realize true load 6DOF posture super-static. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a flow chart of a fixed-point vibration absorption method based on axial momentum exchange of a distributed magnetic suspension flywheel provided by an embodiment of the present invention;

[0024] Figure 2 is a hardware architecture diagram of an electronic device provided by an embodiment of the present invention;

[0025] Figure 3 It is a structural diagram of a fixed-point vibration absorption device based on axial momentum exchange of a distributed magnetic suspension flywheel provided by an embodiment of the present invention;

[0026] Figure 4 It is a physical model of a single magnetic levitation flywheel provided by an embodiment of the present invention;

[0027] Figure 5 It is a schematic diagram of the layout of a group of magnetically suspended flywheels on a star provided by an embodiment of the present invention;

[0028] Figure 6 This is a block diagram of the ultra-quiet satellite micro-vibration control system provided by an embodiment of the present invention.

[0029] Figure 7 It is a driving control block diagram of a magnetic levitation flywheel group provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Please refer to Figure 1 The embodiment of the present invention provides a fixed-point vibration absorption method based on axial momentum exchange of a distributed magnetic suspension flywheel, the method comprising:

[0032] Step 100, establishing a magnetic suspension rotor dynamics model including the rotor axial translation and axial rotation;

[0033] Step 102, determining a control quantity model of a magnetic suspension flywheel group according to the magnetic suspension rotor dynamics model;

[0034] Step 104, determining the active control force and active control torque of the star according to the magnetic suspension flywheel group control quantity model and the star dynamics model;

[0035] Step 106, determining a force / torque distribution matrix of a magnetic suspension flywheel group under the constraints of the active control force of the star body and the active control torque of the star body;

[0036] Step 108, determining the axial vibration force and torque action of each flywheel according to the force / torque distribution matrix of the magnetic suspension flywheel group;

[0037] Step 110, based on the magnetic suspension rotor dynamics model, according to the axial vibration force and torque action of each flywheel, determine the driving current to suppress the vibration.

[0038] Traditional satellite attitude control systems use vibration isolation, vibration damping and other methods to suppress the vibration of the onboard actuators, and perform secondary passive vibration isolation on the load. Through two-stage vibration reduction and isolation, the micro-vibration response of the load is reduced, but the weight and space paid for this are relatively high. This patent, however, targets the distributed magnetic levitation flywheel on the ultra-quiet satellite, and for the first time utilizes the characteristics of active control of the axial momentum and angular momentum of the magnetic levitation flywheel rotor, and proposes a method of actively adjusting the axial vibration of each rotor in the distributed flywheel according to the satellite's attitude information to generate anti-phase vibration to absorb the micro-vibration on the satellite. Without adding any additional hardware, the axial vibration of each rotor is distributed only through the satellite's attitude information, thereby achieving micro-vibration absorption at any point on the satellite and improving the attitude stability of the entire satellite.

[0039] This patent accurately establishes the dynamic model of the magnetic levitation flywheel rotor and the dynamic model of the satellite, and carries out the joint simulation of the control system and the dynamic system, which can be directly applied to model development, especially for the design of high-precision satellite attitude control laws. This model can simulate the attitude of the system with high precision and verify the implementation of the control law, etc., and has direct engineering application value.

[0040] Described below Figure 1 How the various steps are performed.

[0041] Before establishing various models, it is necessary to establish a coordinate system. For the magnetic suspension flywheel system with flexible support, if the rotor and rotating body of the magnetic suspension bearing are regarded as rigid bodies, they constitute a rotating body and are supported in the flywheel housing through electromagnetic coupling; the magnetic suspension stator, flywheel housing and supporting boundary are regarded as rigid assemblies; and the flexibility of the mounting panel is equivalent to a spring damping system, and the rigid assembly is supported on the inertial base through spring damping. Establish the following coordinate system:

[0042] Star-body mass-center orbit system Its origin o is located at the center of mass of the satellite platform, the satellite flight direction is the x-axis, the normal direction of the satellite orbital plane is the y-axis, and the z-axis is determined by the right-hand rule.

[0043] Flywheel k coordinate system o wk x wk y wk z wk Its origin is o wk Located at the center of the flywheel k mounting surface, with the normal line of the mounting surface upward as z wk Axis, y wk The axis lies to the right in the plane, x wk The axes are determined by the right-hand rule.

[0044] For step 100:

[0045] Assume that there are η (η ≥ 3) flywheels installed on the star. In the star's center-of-mass orbit coordinate system, the axial unit vector of the kth flywheel (referred to as flywheel k) is expressed as n wk ; and assume that the momentum amplitude of the flywheel k along the axial direction is p wk and the angular momentum amplitude about the axis is h wk , k∈{1,2,,…,η}.

[0046] Given that the axial degree of freedom and radial degree of freedom of the rotor-boundary system are naturally decoupled, and the axial linear vibration and angular vibration are also naturally decoupled, they are considered as two independent single-degree-of-freedom vibrations. In addition, the rotor structure has low damping, and the momentum p of the rotor in the axial translation is wk and the angular momentum h of the rotation about the axis wk for:

[0047]

[0048] Among them, m wk is the mass of the magnetically suspended rotor; I wk is the polar inertia of the magnetically suspended rotor; z wk is the axial displacement of the magnetically suspended rotor; θ wk It is the angle that the magnetically suspended rotor rotates around the axis.

[0049] The dynamic equations of the rotor's axial translation and axial rotation are:

[0050]

[0051] Among them, f czk (t) is the axial control force exerted by the axial magnetic bearing on the rotor; g czk (t) is the equivalent axial control torque applied by the motor to the rotor mass center.wpk is the force coefficient of the axial magnetic bearing, i wpk is the axial magnetic bearing driving current; k whk is the torque coefficient of the motor, i whk is the driving current of the motor.

[0052] Regarding step 102:

[0053] Step 102 includes:

[0054] S1, establishing a rotor-boundary system dynamics model according to the magnetic suspension rotor dynamics model;

[0055] S2, transforming the rotor-boundary system dynamics model to obtain the vibration control force and torque outputted axially by the rotor;

[0056] S3, obtaining an exchange control force and exchange torque generated by active exchange of axial momentum and angular momentum of the magnetically suspended rotor according to the vibration control force and torque outputted axially from the rotor;

[0057] S4, establishing a magnetic suspension flywheel group control quantity model according to the exchange control force and the exchange torque.

[0058] In one embodiment, S1 includes establishing expressions of exciting force and exciting torque of a combination according to the magnetic suspension rotor dynamics model; wherein the combination is composed of a magnetic bearing stator, a motor stator, a housing and a flexible support boundary of a flywheel;

[0059] The expression is combined with the dynamic characteristics of the magnetic suspension flywheel rotor under the flexible boundary to establish the axial rotor-boundary system dynamic model of the flywheel and its boundary assembly.

[0060] Specifically, the magnetic bearing stator, motor stator, housing and flexible support boundary of the flywheel k constitute a combination, and its exciting force F wzk and torque G wzk is the reaction force and torque of the magnetic bearing and motor on the magnetically suspended rotor:

[0061]

[0062] Considering that the magnetic levitation flywheel rotor is affected by the dynamic characteristics of the flexible boundary, such as Figure 4 As shown in the figure, the axial dynamic model of the flywheel k shell and boundary combination is:

[0063]

[0064] Among them, m gk is the mass of the assembly; I gk is the axial moment of inertia of the assembly; z gk is the displacement of the assembly along the axial direction; θgk is the rotation angle of the assembly around the axis; z sk is the axial displacement of the kth flywheel caused by the rotation of the star; θ sk k is the rotation angle around the axis of the kth flywheel caused by the rotation of the star; gfz , k ggθ c is the axial line and angular support stiffness of the satellite's flexible boundary to the assembly. gz 、c gθ is the damping coefficient of the axial linear vibration and angular vibration of the assembly. Then the vibration force F gzk and torque G gzk They are:

[0065]

[0066] Given that the mechanical clearance of the magnetic bearing, the maximum axial output force, the maximum output torque of the motor, and the maximum speed of the rotor are all subject to certain limitations, the magnetically suspended rotor must meet the following constraints:

[0067]

[0068] Among them, δ zwk is half of the axial clearance of the magnetic suspension rotor; f zwk is the output force limit of the magnetic suspension rotor; t zwk is the output torque limit of the magnetic suspension rotor; h zwk is the angular momentum limit of the magnetically suspended rotor.

[0069] In one embodiment, S2 includes performing Laplace transformation on the rotor-boundary system dynamics model under zero initial conditions to obtain the vibration control force and torque outputted axially by the rotor.

[0070] Specifically, under zero initial conditions, the Laplace transform of the assembly dynamics model (4) can be used to obtain the assembly frequency domain dynamics equation:

[0071]

[0072] in, s is a complex variable.

[0073]

[0074] From formula (5), we can know that the vibration control force and moment transmitted outside the installation boundary are:

[0075]

[0076] Transform formula (7) into:

[0077]

[0078] Substituting equation (9) into equation (8), the vibration control force and torque of the rotor axial output are obtained as follows:

[0079]

[0080] in,

[0081] It can also be seen from formula (10) that the axial movement and rotation are decoupled, and the axial control force and torque can be simplified to:

[0082]

[0083] in,

[0084] Considering that the control force of the rotor will generate a torque rotating around the center of mass, the control force and torque generated by the active exchange of axial momentum and angular momentum of the magnetically suspended rotor can be obtained as follows:

[0085]

[0086] Among them, l wk is the installation position of flywheel k in the orbital coordinate system of the star's center of mass. wk = l wk ×n wk is the torque direction of the axial control force of the magnetic suspension rotor on the center of mass of the star. Combining formula (11), we can get:

[0087]

[0088] It can be seen that the force and torque required for active vibration control of the star can be generated by controlling the vibration of the rotor.

[0089] In one embodiment, S3 includes the exchange control force and the exchange torque combined with the momentum amplitude vector and angular momentum amplitude vector of the flywheel group to obtain a magnetic levitation flywheel group control quantity model; wherein the magnetic levitation flywheel group control quantity model includes the resultant force and resultant torque generated by the axial active linear vibration and active angular vibration of the flywheel group.

[0090] Specifically, aiming at the non-ideal characteristics of the rotor, a stellar dynamics model is established under multi-source disturbance excitation to study the stellar kinematics and the resultant force and torque model of the control of the maglev flywheel group on the stellar.

[0091] In view of the fact that the deformation of the elastic boundaries of the assembly and the satellite cabin plate is small under the active vibration control of the magnetic levitation flywheel rotor, it is assumed that the direction of the control force and torque remains unchanged and is still n wk The rotation of the star θ sbThis will cause the flywheel rotor to rotate and move where it is installed. The flywheel's rotation angle is the star's rotation angle, and the flywheel displacement includes the synthesis of the star's displacement and the displacement caused by the rotation:

[0092]

[0093] Among them, δ sb is the linear displacement at the center of mass of the star; θ sb is the angular displacement at the centroid of the star. Then the projection of the flywheel installation point displacement and rotation angle in the direction of the flywheel rotor axis is:

[0094]

[0095] Generation of control quantity of magnetic levitation flywheel group:

[0096] Substituting formula (15) into formula (13) yields the following relationship:

[0097]

[0098] Let the momentum amplitude vector of the magnetic levitation flywheel group be Angular momentum magnitude vector of the flywheel group Then the total momentum of the flywheel group is p w and the combined angular momentum h w They are:

[0099]

[0100] Among them, A is the flywheel group configuration matrix, A=[n w1 …n wη ], depends on the installation direction of the flywheel axis in the spacecraft. To simplify the verification, it is assumed that the axial stiffness and damping of each flywheel bracket are the same. The force and torque generated by the active vibration control of the flywheel group are obtained by summing both sides of equation (16):

[0101]

[0102] Where B is the flywheel group position matrix, which depends on the installation position and direction of the flywheel in the spacecraft, B = [b w1 …b wη The magnetic suspension flywheel group generates an active control force u through the axial active line vibration and angular vibration. sp and resultant moment τ sh It can be further written in matrix form as:

[0103]

[0104] in,

[0105] It can be seen that through the exchange of axial active momentum and angular momentum of the magnetically suspended rotor group, corresponding control force and torque can be generated, providing an active control means for super-static control of the load.

[0106] Regarding step 104:

[0107] Step 104 may specifically include:

[0108] Build a stellar dynamics model;

[0109] Determine the transmission relationship between the vibration transfer matrix from the load to the center of mass of the star;

[0110] Determine the PID control law for displacement and angular velocity feedback;

[0111] The linear vibration and angular vibration of the satellite mass center are estimated according to the transmission relationship, and the magnetic levitation flywheel group control quantity model performs feed-forward compensation on the vibration at the load according to the linear vibration and angular vibration of the satellite mass center to obtain the residual control force and the residual torque;

[0112] According to the star body dynamics model, the PID control law, the residual control force and the residual torque, the star body active control force and the star body active control torque are obtained.

[0113] In this embodiment, a stellar dynamics model is first established, assuming that the disturbance force on the star is u sd ; The disturbance torque is τ sd Under the combined effect of the on-satellite disturbance and the control force and torque of the magnetically suspended rotor, the satellite dynamics equation is:

[0114]

[0115] Among them, m sb is the mass matrix of the star; I sb is the moment of inertia matrix of the star in its center-of-mass orbital system. Under zero initial conditions, the above dynamic model is subjected to Laplace transformation, and we obtain:

[0116]

[0117] Since the zero-crossing torque of the magnetic levitation flywheel is extremely small, it is used as the reaction wheel. For simplicity, this paper adopts the orthogonal configuration of three magnetic levitation reaction flywheels for star vibration control, such as Figure 5 shown.

[0118] Since it is difficult to install attitude sensors such as gyroscopes and star sensors at the centroid of the satellite in terms of structural layout, and the main goal of the satellite is to monitor the attitude information at the payload, the sensors are generally installed at the payload, so the vibration at the centroid of the satellite needs to be estimated through the vibration at the payload. Here, the vibration transfer matrix T from the payload to the centroid of the satellite can be measured through the vibration transfer test on the ground. ps , there is a relationship:

[0119]

[0120] Among them, δ p is the linear vibration at the load; θ p is the angular vibration at the load.

[0121] The linear vibration and angular vibration of the satellite center of mass can be estimated by the load linear vibration and angular vibration of formula (22), and according to the deformation of formula (19), the vibration at the load caused by the vibration of the satellite can be feedforward compensated during control. At this time, the remaining control force Δu sp and torque Δτ sh :

[0122]

[0123] The magnetic levitation flywheel is used to stably control the ultra-quiet satellite platform. In order to simplify the verification, PID control based on displacement and angular velocity feedback is adopted. The block diagram of the control system is shown in the figure. Figure 6 Assume the PID control law:

[0124]

[0125] Among them, k Pz and k Pθ is the proportional control coefficient, which provides a certain support stiffness for the magnetic bearing; k Iz and k Iθ k is the integral control coefficient, which accumulates the deflection error of the magnetic bearing and improves the control accuracy; Dz and k Dθ is the differential control coefficient, which provides a certain damping for the magnetic bearing. Combining formula (22), we can get:

[0126]

[0127] From equations (23) and (25), we can get the active control force Δu of the star: sp and torque Δτ sh for:

[0128]

[0129] in, is the desired control force and torque.

[0130] It can be seen from this that by providing feedback on the position and attitude of the onboard payload, the magnetically levitated rotor can output force and torque for satellite vibration control through active momentum and angular momentum regulation.

[0131] Regarding step 106:

[0132] In order to realize three-axis attitude control, the axes of at least three flywheels in the onboard flywheel group are not coplanar. In this case, the rank of matrix A is 3 and the rank of matrix M is 6. Given the desired torque, equation (26) has a unique or infinite number of solutions. It is necessary to realize the one-to-one mapping between the desired force / torque and the force / torque of the magnetic suspension flywheel group according to certain indicators or constraints. The optimal allocation will be made based on the required control quantity.

[0133] The flywheel force / torque vector is used to construct the following energy index function:

[0134]

[0135] Where W = W T >0 is the weighted coefficient matrix. for The 2-norm of . At this time, the goal of the torque allocation strategy is to solve the minimum value of the index function J2 under the constraint of equation (26). Construct the Lagrangian function:

[0136]

[0137] Taking the partial derivative of H with respect to the state and the Lagrange multiplier λ, we get:

[0138]

[0139] Multiply both sides of the first equation (29) by W -1 We can get:

[0140]

[0141] Substituting (30) into the second equation of (29) yields:

[0142] λ=(AW -1 M T ) -1 τ sc (31)

[0143] Substituting equation (31) into equation (30), we get the optimal force / torque distribution law of the flywheel:

[0144]

[0145] Among them, the force / torque distribution matrix of the magnetic levitation flywheel group is:

[0146] D=W-1 M T (MW -1 M T ) -1 (33)

[0147] For the command control torque τ sc , when the weight matrix W is the unit matrix, equation (33) becomes ordinary least squares, D = M T (MM T ) -1 is the pseudo-inverse of M and is a constant matrix related to the flywheel configuration. The energy-optimal torque distribution strategy gives a one-to-one linear mapping relationship between the desired force, torque and the flywheel command force, torque through D, which has low energy consumption.

[0148] Regarding step 108:

[0149] The force and torque control quantities of the magnetic levitation flywheel group are:

[0150]

[0151] Thus, the axial vibration force and torque action of each flywheel are obtained.

[0152]

[0153] Regarding step 110:

[0154] According to the rotor axial dynamics model (1), the driving current is:

[0155]

[0156] Among them, E is the η-order unit matrix.

[0157] By adjusting the axial speed and rotational speed of the flywheel, the electromagnetic force / torque acting on the flywheel also acts on the satellite body in the form of a reaction force / torque, thereby realizing the exchange of momentum and angular momentum between the flywheel and the satellite body, and achieving ultra-quiet control of the linear / angular vibration of the satellite platform.

[0158] In summary, by actively exciting the magnetically suspended rotor group to generate the force and torque for satellite micro-vibration control, and exchanging controlled momentum and angular momentum with the satellite body, the vibration at any point can be actively suppressed, and the vibration response from any fixed point such as the load is absorbed into the magnetically suspended rotor, similar to pumping water to another reservoir through a water pump, thus achieving a "pumping" effect on micro-vibration energy. It can be expected that this method will have extremely high vibration control efficiency and achieve true payload 6DOF posture super-static.

[0159] in accordance with Figure 6 and Figure 7As shown in the control block diagram, a simulation model is established using Simulink to conduct joint simulation verification of the dynamics and control systems of the system consisting of the magnetic levitation flywheel group and the satellite platform.

[0160] It can be seen that this patented control method can be used for any ultra-quiet satellite. It can not only realize the attitude control of the satellite platform, but also realize the fixed-point micro-vibration absorption of any point on the satellite, and realize the ultra-precise, ultra-stable and ultra-quiet attitude control of payloads such as optical cameras and laser communication equipment. It has strong versatility, broad application fields and good application prospects.

[0161] like Figure 2 , Figure 3 As shown, the embodiment of the present invention provides a fixed-point vibration absorption device based on the axial momentum exchange of a distributed magnetic suspension flywheel. The device embodiment can be implemented by software, or by hardware or a combination of software and hardware. From the hardware level, Figure 2 As shown, it is a hardware architecture diagram of an electronic device in which a fixed-point vibration absorption device based on axial momentum exchange of a distributed magnetic suspension flywheel provided by an embodiment of the present invention is located. Figure 2 In addition to the processor, memory, network interface, and non-volatile memory shown, the electronic device in the embodiment may also include other hardware, such as a forwarding chip responsible for processing messages, etc. Taking software implementation as an example, Figure 3 As shown, as a device in a logical sense, the CPU of the electronic device in which it is located reads the corresponding computer program in the non-volatile memory into the internal memory and runs it.

[0162] like Figure 3 As shown, this embodiment provides a fixed-point vibration absorption device based on axial momentum exchange of a distributed magnetic suspension flywheel, comprising:

[0163] The first processing module is used to establish a magnetic suspension rotor dynamics model including the rotor axial translation and axial rotation;

[0164] A second processing module is used to determine a control quantity model of a magnetic suspension flywheel group according to the magnetic suspension rotor dynamics model;

[0165] A third processing module is used to determine the active control force and active control torque of the star according to the magnetic suspension flywheel group control quantity model and the star dynamics model;

[0166] A fourth processing module, used for determining a force / torque distribution matrix of a magnetic suspension flywheel group under the constraints of the active control force of the star body and the active control torque of the star body;

[0167] A fifth processing module, used to determine the axial vibration force and torque action of each flywheel according to the force / torque distribution matrix of the magnetic suspension flywheel group;

[0168] The sixth processing module is used to determine the driving current to suppress vibration based on the magnetic suspension rotor dynamics model and the axial vibration force and torque action of each flywheel.

[0169] In one embodiment, the second processing module is further configured to perform the following steps:

[0170] include:

[0171] Establishing a rotor-boundary system dynamics model according to the magnetically suspended rotor dynamics model;

[0172] Transforming the rotor-boundary system dynamics model to obtain the vibration control force and torque outputted axially by the rotor;

[0173] According to the vibration control force and torque outputted axially by the rotor, an exchange control force and exchange torque generated by active exchange of axial momentum and angular momentum of the magnetically suspended rotor are obtained;

[0174] Establishing a control quantity model of a magnetic suspension flywheel group according to the exchange control force and the exchange torque;

[0175] The magnetic suspension rotor dynamic model is as follows:

[0176]

[0177] Among them, m wk is the mass of the magnetically suspended rotor, f czk is the equivalent control force applied by the axial magnetic bearing to the rotor mass center, g czk k is the equivalent control torque applied by the motor to the rotor mass center, wpk is the axial magnetic bearing force coefficient, i wpk is the axial magnetic bearing driving current, k whk is the torque coefficient of the motor, i whk is the driving current of the motor, I wk is the polar inertia of the magnetically suspended rotor, z wk is the axial displacement of the magnetically suspended rotor, θ wk is the angle that the magnetic suspension rotor rotates around the axis, p wk is the axial translation momentum of the rotor, h wk is the angular momentum of rotation about the axis.

[0178] In a possible embodiment, establishing a rotor-boundary system dynamics model according to the magnetic suspension rotor dynamics model includes:

[0179] According to the magnetic suspension rotor dynamics model, an expression of the exciting force and exciting torque of the assembly is established; wherein the assembly is composed of a magnetic bearing stator, a motor stator, a housing and a flexible support boundary of the flywheel;

[0180] The expression is combined with the dynamic characteristics of the magnetic suspension flywheel rotor under the flexible boundary to establish the axial rotor-boundary system dynamic model of the flywheel and its boundary assembly;

[0181] The expression is as follows:

[0182]

[0183] Among them, F wzk The exciting force, G wzk is the exciting torque, p wk is the axial translation momentum of the rotor, h wk is the angular momentum of rotation about the axis, f czk is the equivalent control force applied by the axial magnetic bearing to the rotor mass center, g czk is the equivalent control torque applied by the motor to the rotor mass center;

[0184] The rotor-boundary system dynamics model is as follows:

[0185]

[0186]

[0187] Among them, m gk is the mass of the assembly, I gk is the axial moment of inertia of the assembly, z gk is the displacement of the assembly along the axial direction, θ gk is the rotation angle of the assembly around the axis, z sk is the axial displacement of the kth flywheel caused by the rotation of the star, θ sk is the rotation angle around the axis of the kth flywheel caused by the rotation of the star, k gfz , k ggθ is the axial line and angular support stiffness of the satellite flexible boundary to the assembly, c gz 、c gθ is the damping coefficient of the axial linear vibration and angular vibration of the assembly, F gzk is the vibration force transmitted outside the combination, G gzk is the vibration torque transmitted outside the assembly.

[0188] In a possible embodiment, transforming the rotor-boundary system dynamics model to obtain the vibration control force and torque outputted axially by the rotor includes:

[0189] Under zero initial conditions, Laplace transform is performed on the rotor-boundary system dynamics model to obtain the vibration control force and torque outputted in the rotor axial direction;

[0190] The vibration control force and torque outputted by the rotor axial direction are as follows:

[0191]

[0192] Among them, c gz 、c gθ is the damping coefficient of the axial linear vibration and angular vibration of the assembly, s is a complex variable.

[0193] In a possible embodiment, establishing a magnetic suspension flywheel group control quantity model according to the exchange control force and the exchange torque includes:

[0194] The exchange control force and the exchange torque are combined with the momentum amplitude vector and angular momentum amplitude vector of the flywheel group to obtain a magnetic suspension flywheel group control quantity model; wherein the magnetic suspension flywheel group control quantity model includes the resultant force and torque generated by the axial active linear vibration and active angular vibration of the flywheel group;

[0195] The exchange control force and the exchange torque are as follows:

[0196]

[0197] Among them, u wk To exchange control force, τ wk is the exchange torque, l wk is the installation position of flywheel k in the orbital coordinate system of the star's center of mass, b wk = l wk ×n wk , n wk is the axial unit vector of the kth flywheel;

[0198] The resultant force u generated by the axial active linear vibration and active angular vibration of the flywheel group sp and resultant moment τ sh The expression is as follows:

[0199]

[0200] Among them, A is the configuration matrix of the magnetic suspension flywheel group, A=[n w1 … n wm ], depends on the installation direction of the flywheel axis in the spacecraft, B is the flywheel group position matrix, depends on the installation position and direction of the flywheel in the spacecraft, B = [b w1 …b wm ], let the momentum amplitude vector of the flywheel group be Angular momentum amplitude vector of magnetically suspended flywheel group

[0201] In a possible embodiment, determining the active control force and active control torque of a star body according to the control quantity model of the magnetic levitation flywheel group and the star body dynamics model includes:

[0202] Build a stellar dynamics model;

[0203] Determine the transmission relationship between the vibration transfer matrix from the load to the center of mass of the star;

[0204] Determine the PID control law for displacement and angular velocity feedback;

[0205] The linear vibration and angular vibration of the satellite mass center are estimated according to the transmission relationship, and the magnetic levitation flywheel group control quantity model performs feed-forward compensation on the vibration at the load according to the linear vibration and angular vibration of the satellite mass center to obtain the residual control force and the residual torque;

[0206] According to the star dynamics model, the PID control law, the residual control force and the residual torque, a star active control force and a star active control torque are obtained;

[0207] The stellar dynamics equation is

[0208]

[0209] Among them, m sb is the mass matrix of the star; I sb is the moment of inertia matrix of the star in its center-of-mass orbital system, δ sb is the displacement of the star; θ sb is the angular displacement of the star; u sd is the disturbance force on the star; τ sd is the disturbance torque on the star; u sp is the control force of the magnetic suspension flywheel group; τ sh Control torque for magnetically suspended flywheel group;

[0210] Active control force of the star Δu sp and the active control torque Δτ of the star sh as follows:

[0211]

[0212] in,

[0213] is the desired control force and torque.

[0214] In a possible embodiment, the force / torque distribution matrix is:

[0215] D=W-1 M T (MW- 1 M T )- 1

[0216] Where W = W T >0 is the weighted coefficient matrix,

[0217] The axial vibration force and torque of each flywheel are:

[0218]

[0219] The driving current is

[0220]

[0221] Among them, E is the η-order unit matrix.

[0222] It is understandable that the structure illustrated in the embodiment of the present invention does not constitute a specific limitation on a fixed-point vibration absorbing device based on the axial momentum exchange of a distributed magnetic levitation flywheel. In other embodiments of the present invention, a fixed-point vibration absorbing device based on the axial momentum exchange of a distributed magnetic levitation flywheel may include more or fewer components than shown in the figure, or combine some components, or split some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0223] The information interaction, execution process and other contents between the modules in the above-mentioned device are based on the same concept as the embodiment of the method of the present invention. For specific contents, please refer to the description in the embodiment of the method of the present invention, and no further description is given here.

[0224] An embodiment of the present invention further provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, a fixed-point vibration absorption method based on axial momentum exchange of a distributed magnetic levitation flywheel in any embodiment of the present invention is implemented.

[0225] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the processor executes a fixed-point vibration absorption method based on axial momentum exchange of a distributed magnetic levitation flywheel in any embodiment of the present invention.

[0226] Specifically, a system or device equipped with a storage medium can be provided, on which software program code that implements the functions of any of the above-mentioned embodiments is stored, and a computer (or CPU or MPU) of the system or device can be enabled to read and execute the program code stored in the storage medium.

[0227] In this case, the program code itself read from the storage medium can realize the function of any one of the above-mentioned embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present invention.

[0228] The storage medium embodiments for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program code can be downloaded from a server computer by a communication network.

[0229] In addition, it should be clear that the functions of any of the above embodiments can be implemented not only by executing the program code read by the computer, but also by enabling an operating system operating on the computer to complete part or all of the actual operations based on instructions from the program code.

[0230] In addition, it can be understood that the program code read from the storage medium is written to a memory provided in an expansion board inserted into the computer or to a memory provided in an expansion module connected to the computer, and then based on the instructions of the program code, a CPU installed on the expansion board or expansion module is enabled to perform part or all of the actual operations, thereby realizing the functions of any of the above-mentioned embodiments.

[0231] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0232] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc., various media that can store program codes.

[0233] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fixed-point vibration absorption method based on axial momentum exchange of a distributed magnetic levitation flywheel, characterized in that: include: Establish a magnetically suspended rotor dynamics model including the rotor's axial translation and axial rotation; Determining a control quantity model of a magnetic suspension flywheel group according to the magnetic suspension rotor dynamics model; Determine the active control force and active control torque of the star according to the magnetic levitation flywheel group control quantity model and the star dynamics model; Under the constraints of the active control force of the star body and the active control torque of the star body, determining the force / torque distribution matrix of the magnetic suspension flywheel group; Determining the axial vibration force and torque action of each flywheel according to the force / torque distribution matrix of the magnetic suspension flywheel group; On the basis of the magnetic suspension rotor dynamics model, the driving current is determined to suppress the vibration according to the axial vibration force and torque action of each flywheel.

2. The fixed-point vibration absorption method according to claim 1, characterized in that: Determining the control quantity model of the magnetic suspension flywheel group according to the magnetic suspension rotor dynamics model includes: Establishing a rotor-boundary system dynamics model according to the magnetically suspended rotor dynamics model; Transforming the rotor-boundary system dynamics model to obtain the vibration control force and torque outputted axially by the rotor; According to the vibration control force and torque outputted axially by the rotor, an exchange control force and exchange torque generated by active exchange of axial momentum and angular momentum of the magnetically suspended rotor are obtained; Establishing a control quantity model of a magnetic suspension flywheel group according to the exchange control force and the exchange torque; The magnetic suspension rotor dynamic model is as follows: Among them, m wk is the mass of the magnetically suspended rotor, f czk is the equivalent control force applied by the axial magnetic bearing to the rotor mass center, g czk k is the equivalent control torque applied by the motor to the rotor mass center, wpk is the axial magnetic bearing force coefficient, i wpk is the axial magnetic bearing driving current, k whk is the torque coefficient of the motor, i whk is the driving current of the motor, I wk is the polar inertia of the magnetically suspended rotor, z wk is the axial displacement of the magnetically suspended rotor, θ wk is the angle that the magnetic suspension rotor rotates around the axis, p wk is the axial translation momentum of the rotor, h wk is the angular momentum of rotation about the axis.

3. The fixed-point vibration absorption method according to claim 2, characterized in that: The step of establishing a rotor-boundary system dynamics model according to the magnetic suspension rotor dynamics model comprises: According to the magnetic suspension rotor dynamics model, an expression of the exciting force and exciting torque of the assembly is established; wherein the assembly is composed of a magnetic bearing stator, a motor stator, a housing and a flexible support boundary of the flywheel; The expression is combined with the dynamic characteristics of the magnetic suspension flywheel rotor under the flexible boundary to establish the axial rotor-boundary system dynamic model of the flywheel and its boundary assembly; The expression is as follows: Among them, F wzk The exciting force, G wzk is the exciting torque, p wk is the axial translation momentum of the rotor, h wk is the angular momentum of rotation around the axis, f czk is the equivalent control force applied by the axial magnetic bearing to the rotor mass center, g czk is the equivalent control torque applied by the motor to the rotor mass center; The rotor-boundary system dynamics model is as follows: Among them, m gk is the mass of the assembly, I gk is the axial moment of inertia of the assembly, z gk is the displacement of the assembly along the axial direction, θ gk is the rotation angle of the assembly around the axis, z sk is the axial displacement of the kth flywheel caused by the rotation of the star, θ sk is the rotation angle around the axis of the kth flywheel caused by the rotation of the star, k gfz , k ggθ is the axial line and angular support stiffness of the satellite flexible boundary to the assembly, c gz 、c gθ is the damping coefficient of the axial linear vibration and angular vibration of the assembly, F gzk is the vibration force transmitted outside the combination, G gzk is the vibration torque transmitted outside the combination.

4. The fixed-point vibration absorption method according to claim 2, characterized in that: The step of transforming the rotor-boundary system dynamics model to obtain the vibration control force and torque outputted axially by the rotor includes: Under zero initial conditions, Laplace transform is performed on the rotor-boundary system dynamics model to obtain the vibration control force and torque outputted in the rotor axial direction; The vibration control force and torque outputted by the rotor axial direction are as follows: Among them, c gz 、c gθ is the damping coefficient of the axial linear vibration and angular vibration of the assembly, s is a complex variable.

5. The fixed-point vibration absorption method according to claim 2, characterized in that: The method of establishing a magnetic suspension flywheel group control quantity model according to the exchange control force and the exchange torque includes: The exchange control force and the exchange torque are combined with the momentum amplitude vector and angular momentum amplitude vector of the flywheel group to obtain a magnetic suspension flywheel group control quantity model; wherein the magnetic suspension flywheel group control quantity model includes the resultant force and torque generated by the axial active linear vibration and active angular vibration of the flywheel group; The exchange control force and the exchange torque are as follows: Among them, u wk To exchange control force, τ wk is the exchange torque, l wk is the installation position of flywheel k in the orbital coordinate system of the star's center of mass, b wk = l wk ×n wk , n wk is the axial unit vector of the kth flywheel; The resultant force u generated by the axial active linear vibration and active angular vibration of the flywheel group sp and resultant moment τ sh The expression is as follows: Among them, A is the configuration matrix of the magnetic suspension flywheel group, A=[n w1 …n wm ], depends on the installation direction of the flywheel axis in the spacecraft, B is the flywheel group position matrix, depends on the installation position and direction of the flywheel in the spacecraft, B = [b w1 …b wm ], let the momentum amplitude vector of the flywheel group be Angular momentum amplitude vector of magnetically suspended flywheel group 6. The fixed-point vibration absorption method according to claim 1, characterized in that: The determining of the active control force and the active control torque of the star body according to the magnetic suspension flywheel group control quantity model and the star body dynamics model comprises: Build a stellar dynamics model; Determine the transmission relationship between the vibration transfer matrix from the load to the center of mass of the star; Determine the PID control law for displacement and angular velocity feedback; The linear vibration and angular vibration of the satellite mass center are estimated according to the transmission relationship, and the magnetic levitation flywheel group control quantity model performs feed-forward compensation on the vibration at the load according to the linear vibration and angular vibration of the satellite mass center to obtain the residual control force and the residual torque; According to the star dynamics model, the PID control law, the residual control force and the residual torque, a star active control force and a star active control torque are obtained; The stellar dynamics equation is: Among them, m sb is the mass matrix of the star; I sb is the moment of inertia matrix of the star in its center-of-mass orbital system, δ sb is the displacement of the star; θ sb is the angular displacement of the star; u sd is the disturbance force on the star; τ sd is the disturbance torque on the star; u sp is the control force of the magnetic suspension flywheel group; τ sh Control torque for magnetically suspended flywheel group; Active control force of the star Δu sp and the active control torque Δτ of the star sh as follows: in, is the desired control force and torque.

7. The fixed-point vibration absorption method according to claim 2, characterized in that: The force / torque distribution matrix is: D=W -1 I T (MW) -1 I T ) -1 Where W = W T >0 is the weighted coefficient matrix, The axial vibration force and torque of each flywheel are: The driving current is Among them, E is the η-order unit matrix.

8. A fixed-point vibration absorption device based on axial momentum exchange of a distributed magnetic suspension flywheel, characterized in that: include: The first processing module is used to establish a magnetic suspension rotor dynamics model including the rotor axial translation and axial rotation; A second processing module is used to determine a control quantity model of a magnetic suspension flywheel group according to the magnetic suspension rotor dynamics model; A third processing module is used to determine the active control force and active control torque of the star according to the magnetic suspension flywheel group control quantity model and the star dynamics model; A fourth processing module, used for determining a force / torque distribution matrix of a magnetic suspension flywheel group under the constraints of the active control force of the star body and the active control torque of the star body; A fifth processing module, used to determine the axial vibration force and torque action of each flywheel according to the force / torque distribution matrix of the magnetic suspension flywheel group; The sixth processing module is used to determine the driving current to suppress vibration based on the magnetic suspension rotor dynamics model and the axial vibration force and torque action of each flywheel.

9. An electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to execute the method according to any one of claims 1 to 7.

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