Rocket modal determination method and device, medium and equipment

Abstract

The invention provides a rocket modal determination method. The rocket modal determination method comprises the steps of determining a shape function corresponding to each cabin section of a rocket according to a dynamical model of a rocket cabin section; determining a target frequency equation according to the shape function corresponding to each cabin section, the free boundary conditions of the two ends of the rocket and the boundary equation connected between the cabin sections; solving the target frequency equation to obtain the inherent frequency of the concerned frequency band; determining an undetermined coefficient of the shape function according to the inherent frequency, and substituting the undetermined coefficient into the shape function of the corresponding cabin section to obtain a full-rocket vibration mode; thus, a frequency equation is determined according to the shape function of each cabin section, the free boundary conditions of the two ends of the rocket and the boundary equation of connection between the cabin sections, then the frequency equation is solved, and the inherent frequency needed by the modal is obtained; an undetermined coefficient value of the shape function is calculated under the inherent frequency, a median of the undetermined coefficient is substituted into the shape function, and a full-rocket vibration mode can be obtained; therefore, the rocket mode is quickly determined, and the design efficiency of the whole rocket body is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of launch vehicle design, and in particular to a method, device, medium and equipment for determining a rocket mode. Background Art

[0002] In the early stages of launch vehicle development, there are no clear parameters for the rocket body structure, materials, and main mass parameters. However, due to the need for program demonstration, it is necessary to preliminarily determine the rocket mode in order to carry out preliminary design work such as rocket body attitude control and POGO stabilization.

[0003] In the related art, when determining the rocket mode, a large number of models need to be established, and model establishment is time-consuming, which in turn affects the efficiency of the entire rocket body design.

[0004] Based on this, a rapid evaluation and calculation method for rocket modes is needed to solve the above technical problems. Summary of the invention

[0005] In response to the problems existing in the prior art, the embodiments of the present invention provide a method, device, medium and equipment for determining the rocket mode, so as to solve or partially solve the technical problem in the prior art that the rocket mode cannot be quickly determined in the early stage of the development of the launch vehicle, thereby affecting the design efficiency of the entire rocket body.

[0006] A first aspect of the present invention provides a method for determining a rocket mode, the method comprising:

[0007] Determine the shape function corresponding to each section of the rocket based on the dynamic model of the rocket section;

[0008] Determine the target frequency equation according to the shape function corresponding to each compartment, the free boundary conditions at both ends of the rocket and the boundary equations connecting the compartments;

[0009] Solving the target frequency equation to obtain the natural frequency of the frequency band of interest;

[0010] The undetermined coefficients of the shape function are determined according to the natural frequency, and the undetermined coefficients are substituted into the shape function of the corresponding compartment to obtain the full arrow vibration shape.

[0011] In the above scheme, the frequency equation is determined according to the shape function corresponding to each compartment, the free boundary conditions at both ends of the rocket and the boundary equations connecting the compartments, including:

[0012] According to the free boundary conditions at both ends of the rocket, the shape function corresponding to the first compartment is subjected to second-order and third-order derivatives, and the shape function corresponding to the last compartment is subjected to second-order and third-order derivatives, to obtain a first boundary equation group; the first boundary equation group contains undetermined coefficients of the corresponding shape function;

[0013] Processing the shape functions of the intermediate compartments according to the boundary equations of the connection between the compartments to obtain a second set of boundary equations; the second set of boundary equations contains undetermined coefficients corresponding to the shape functions;

[0014] Extract the undetermined coefficients from the first boundary equation group and the second boundary equation group to obtain the undetermined coefficient vector A coefficient matrix A(ω) is constructed based on the remaining parameters in the first boundary equation group and the second boundary equation group; wherein,

[0015] according to Determine that the determinant value of the coefficient matrix A(ω) is 0. When the determinant value of the coefficient matrix A(ω) is 0, the initial frequency equation is f(ω)=det(A(ω))=0;

[0016] A target frequency equation is determined according to the initial frequency equation.

[0017] In the above solution, determining the target frequency equation according to the initial frequency equation includes:

[0018] The target frequency equation g(ω) is determined according to the formula g(ω)=lg(|f(ω)|).

[0019] In the above scheme, solving the target frequency equation to obtain the natural frequency of the frequency band of interest includes:

[0020] A peak search function is used to search for a plurality of initial local minima for a curve corresponding to the target frequency equation; and the plurality of local minima are determined as the natural frequencies.

[0021] In the above solution, determining the undetermined coefficients of the shape function according to the natural frequency includes:

[0022] Substituting the i-th natural frequency into the coefficient matrix yields A(ω i ) value;

[0023] Determining a plurality of initial eigenvalues ​​and a plurality of initial eigenvectors of the coefficient matrix;

[0024] Determining a target eigenvalue from the multiple initial eigenvalues ​​and determining a first target eigenvector corresponding to the target eigenvalue;

[0025] Each value in the first target feature vector is determined as an undetermined coefficient of the shape function.

[0026] In the above solution, the step of determining a target eigenvalue from the multiple initial eigenvalues ​​and determining a first target eigenvector corresponding to the target eigenvalue includes:

[0027] If it is determined that the modulus of the minimum eigenvalue among the multiple initial eigenvalues ​​differs from the modulus of the remaining eigenvalues ​​by at least one or more orders of magnitude, the minimum eigenvalue is determined as the target eigenvalue;

[0028] A feature vector corresponding to the target feature value is determined as the first target feature vector.

[0029] In the above solution, the step of determining a target eigenvalue from the multiple initial eigenvalues ​​and determining a first target eigenvector corresponding to the target eigenvalue includes:

[0030] determining a minimum eigenvalue from the plurality of initial eigenvalues;

[0031] If it is determined that there is at least one reference eigenvalue in the remaining eigenvalues ​​whose modulus is at the same order of magnitude as the minimum eigenvalue, the minimum eigenvalue and the reference eigenvalue are used to determine the target eigenvalue;

[0032] A feature vector corresponding to the target feature value is determined as the first target feature vector.

[0033] A second aspect of the present invention provides a device for determining a rocket mode, the device comprising:

[0034] A first determining unit is used to determine a shape function corresponding to each rocket compartment according to a dynamics model of the rocket compartment;

[0035] A second determination unit is used to determine a target frequency equation according to a shape function corresponding to each compartment, free boundary conditions at both ends of the rocket, and a boundary equation connecting the compartments;

[0036] A solving unit, used for solving the target frequency equation to obtain the natural frequency of the frequency band of interest;

[0037] The third determination unit is used to determine the undetermined coefficients of the shape function according to the natural frequency, and substitute the undetermined coefficients into the shape function of the corresponding compartment to obtain the full arrow vibration shape.

[0038] According to a third aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the steps of any one of the methods described in the first aspect are implemented.

[0039] According to a fourth aspect of the present invention, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method according to any one of claims 1 to 7 when executing the program.

[0040] The present invention provides a method, device, medium and equipment for determining rocket modes, the method comprising: determining the shape function corresponding to each compartment of the rocket according to the dynamic model of the rocket compartment; determining the target frequency equation according to the shape function corresponding to each compartment, the free boundary conditions at both ends of the rocket and the boundary equations connecting the compartments; solving the target frequency equation to obtain the natural frequency of the frequency band of interest; determining the undetermined coefficients of the shape function according to the natural frequency, substituting the undetermined coefficients into the shape function of the corresponding compartment to obtain the full arrow vibration mode; in this way, the shape function corresponding to each compartment is first determined according to the dynamic model of the rocket compartment, and the shape function at this time There are still unknown undetermined coefficients; then the frequency equation can be determined according to the shape function of each compartment, the free boundary conditions at both ends of the rocket and the boundary equations connecting the compartments, and then the frequency equation is solved to obtain the natural frequency required by the mode; the natural frequency is substituted back into the coefficient matrix to determine the final eigenvalue and eigenvector, and each value in the eigenvector is the value of the undetermined coefficient of the shape function. Finally, the value of the undetermined coefficient is substituted into the corresponding shape function to obtain the full arrow vibration shape required by the mode; in this way, in the early stage of launch vehicle development, the rocket mode can be quickly determined without a lot of complex work such as modeling, thereby ensuring the design efficiency of the entire rocket body. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0042] Figure 1 A schematic flow chart of a method for determining a rocket mode according to an embodiment of the present invention is shown;

[0043] Figure 2 A schematic diagram of an initial frequency equation function curve according to an embodiment of the present invention is shown;

[0044] Figure 3 A schematic diagram of the natural frequency found according to an embodiment of the present invention is shown;

[0045] Figure 4 A schematic structural diagram of a device for determining a rocket mode according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0046] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0047] The present invention provides a method for determining a rocket mode, such as Figure 1 As shown, the method mainly includes the following steps:

[0048] S110, determining a shape function corresponding to each rocket compartment according to a dynamic model of the rocket compartment.

[0049] In the early stage of launch vehicle design, the rocket body structure has not yet been refined and modeled. At this time, the rocket mode needs to be determined in combination with the dynamic model of the rocket compartment. The Euler beam theory is used to simplify the dynamic model of a single compartment, and the Euler beam dynamic equation of a single compartment can be obtained as follows:

[0050]

[0051] In the above dynamic equation, x is an arbitrary position point on the cabin, t is the time, y(x, t) is the lateral vibration displacement of the position x on the cabin at the time t, f(x, t) is the external force at the position x on the cabin at the time t, ρ is the equivalent linear density of the cabin, E is the elastic modulus of the main material of the cabin, and I is the moment of inertia of the cabin section.

[0052]

[0053] In formula (2), d is the outer diameter of the compartment, t h is the equivalent wall thickness of the tank, m s is the equivalent mass of the cabin, ρ s is the material density of the compartment, and l is the length of the compartment.

[0054] The Euler beam dynamics equation is solved using the separation of variables method, and the solution is:

[0055] y(x,t)=Y(x)T(t) (4)

[0056] In formula (4), Y(x) is the shape function and T(t) is the time function; A 0 is the amplitude, ω is the natural frequency, is the initial phase. Among them, T(t) can be solved by the initial vibration condition.

[0057] The expression of the shape function of a single compartment is shown in formula (5):

[0058] Y(x)=Acos(βx)+Bsin(βx)+Ccosh(βx)+Dsinh(βx) (5)

[0059] In formula (5), A, B, C, and D are unknown coefficients related to the boundary conditions; β is an intermediate variable related to the equivalent linear density, elastic modulus, and moment of inertia of the compartment. When ω is the natural frequency, Y(x) is the vibration mode at the natural frequency.

[0060] It should be noted that when determining the rocket mode, it is mainly necessary to determine the natural frequency and the vibration mode under the natural frequency. Therefore, it is necessary to determine the frequency equation first, and solve the natural frequency according to the frequency equation. Since the undetermined coefficients of the shape function are still unknown values, it is necessary to determine the undetermined coefficients according to the natural frequency, and finally substitute the undetermined coefficients into the shape function to obtain the corresponding vibration mode.

[0061] S111, determining the target frequency equation according to the shape function corresponding to each compartment, the free boundary conditions at both ends of the rocket and the boundary equations connecting the compartments.

[0062] Since the rocket consists of multiple compartments, each compartment has a corresponding shape function. According to formula (5), the shape function corresponding to m compartments can be derived as follows:

[0063]

[0064] In formula (6), Y 1 (x) is the shape function of the first compartment, Y 2 (x) is the shape function of the second compartment, Y m (x) is the shape function of the mth compartment; A 1 , B 1 , C 1 , D 1 Y 1 Undetermined coefficient of (x); A 2 , B 2 , C 2 , D 2 Y 2 Undetermined coefficient of (x); A m , B m , C m , D m Y m (x) is the unknown coefficient; the β 1 is the first intermediate variable, β 2 is the second intermediate variable, β m is the mth intermediate variable.

[0065] In one embodiment, the frequency equation is determined according to the shape function corresponding to each compartment, the free boundary conditions at both ends of the rocket, and the boundary equations connecting the compartments, including:

[0066] According to the free boundary conditions at both ends of the rocket, the shape function corresponding to the first compartment is derived by the second order and the third order, and the shape function corresponding to the last compartment is derived by the second order and the third order, to obtain the first boundary equation group; the first boundary equation group contains the undetermined coefficients of the corresponding shape function;

[0067] The shape functions of the intermediate compartments are processed according to the boundary equations of the connection between the compartments to obtain a second set of boundary equations; the second set of boundary equations contains undetermined coefficients of the corresponding shape functions;

[0068] Extract the undetermined coefficients from the first boundary equation group and the second boundary equation group to obtain the undetermined coefficient vector The coefficient matrix A(ω) is constructed based on the remaining parameters in the first boundary equation group and the second boundary equation group; wherein,

[0069] according to Determine the determinant value of the coefficient matrix A(ω) to be 0. When the determinant value of the coefficient matrix A(ω) is 0, the initial frequency equation is f(ω)=det(A(ω))=0;

[0070] The target frequency equation is determined based on the initial frequency equation.

[0071] Specifically, the free boundary conditions at both ends are as follows:

[0072]

[0073] In formula (7), Y 1 ″ is the second-order derivative of the shape function corresponding to the first compartment, Y 1 ”' is the third-order derivative of the shape function corresponding to the first compartment, Y″ m is the second-order derivative of the shape function corresponding to the mth compartment, Y”' m is the third-order derivative of the shape function corresponding to the mth compartment, l m is the length of the mth compartment.

[0074] The boundary equations for the connections between compartments are as follows:

[0075]

[0076] In formula (8), n is the compartment number, n = 2, 3, 4...m, m is the total number of compartments; Y n-1 is the shape function corresponding to the n-1th compartment, Y nis the shape function corresponding to the nth compartment, Y′ n-1 is the first-order derivative of the shape function corresponding to the n-1th compartment, Y′ n is the first-order derivative of the shape function corresponding to the nth compartment, Y″ n-1 is the second-order derivative of the shape function corresponding to the n-1th compartment, Y″ n is the second-order derivative of the shape function corresponding to the nth compartment, Y″′ n-1 is the third-order derivative of the shape function corresponding to the n-1th compartment, Y″′ n is the third-order derivative of the shape function corresponding to the nth compartment, l n is the length of the nth compartment, l n-1 is the length of the n-1th compartment, E n is the elastic modulus of the main material of the nth compartment, E n-1 is the elastic modulus of the main material of the n-1th compartment, I n is the moment of inertia of the compartment section of the nth compartment, I n-1 is the section moment of inertia of the n-1th section.

[0077] In order to more clearly describe the unknown coefficient vector The expression of the coefficient matrix A(ω) is given here by taking the number of compartments m = 3 as an example:

[0078] When m=3, formula (7) can be expressed as follows:

[0079]

[0080] The boundary equations for the connection between compartments include two groups. When n = 2, formula (8) can be converted to:

[0081]

[0082] When n=3, formula (8) can be converted to:

[0083]

[0084] When m=3, there are three shape functions, as shown in the following formula:

[0085]

[0086] From formula (12), we can see that the unknown coefficients of the shape function include: A 1 , B 1 , C 1 , D 1 , A 2 , B 2 , C 2 , D 2 and A3 , B 3 , C 3 , D 3 ;

[0087] According to formula (12), we can get:

[0088]

[0089]

[0090] Formulas (9), (10), and (11) contain a total of 12 boundary equations. Combined with formulas (13), (14), and (15), it can be seen that each boundary equation is a linear equation about the unknown coefficients. Therefore, the remaining parameters (parameters other than the unknown coefficients) in the boundary equations can be extracted to form the coefficient matrix A(ω).

[0091] Take the first boundary equation in formula (9) as an example to explain in detail:

[0092] Y 1 ″(x) can be expressed as: in, is a 1×12 matrix,

[0093]

[0094] Then there is, in, For β 1 The 1×12 matrix, due to β 1 is related to ω, so is also a 1×12 matrix with respect to ω, This is the first row in the coefficient matrix A(ω).

[0095] According to the same method, for the remaining 11 boundary equations in (9)(10)(11), the corresponding 1×12 matrices about ω can be determined, which are The coefficient matrix A(ω) is the second to twelfth row. The final A(ω) is a 12×12 matrix, and the following formula exists:

[0096]

[0097] It is understandable that since the solution is meaningless when the unknown coefficient in the coefficient vector is equal to 0, if This is equivalent to the determinant value of A(ω) being 0, so the initial frequency equation f(ω) can be obtained:

[0098] f(ω)=det(A(ω))=0 (17)

[0099] Formula (17) is the initial frequency equation about ω. There are finite roots that satisfy the frequency equation. Arranging all the roots from small to large will give the natural frequency ω of each order of the whole arrow. 1 ,ω 2 ,ω 3 .......

[0100] However, it is very difficult to directly solve the initial frequency equation of formula (17) because the solution of the initial frequency equation is relatively complicated for multiple compartments, and the initial frequency equation function often grows exponentially as ω increases. The obtained initial frequency equation function curve is as follows: Figure 2 As shown, from Figure 2 It can be seen that there is no natural frequency.

[0101] Based on this, the present invention transforms the root-finding problem into a problem of finding a "local minimum value" to solve the natural frequency of the entire arrow. Therefore, it is also necessary to determine the target frequency equation based on the initial frequency equation, as follows:

[0102] The target frequency equation g(ω) is determined according to formula (18):

[0103] g(ω)=lg(|f(ω)|) (18)

[0104] S112, solving the target frequency equation to obtain the natural frequency of the frequency band of interest.

[0105] In one implementation, solving the target frequency equation to obtain the natural frequency of the frequency band of interest includes:

[0106] Using the peak finding function to find multiple initial local minima for the curve corresponding to the target frequency equation;

[0107] Multiple local minima are identified as natural frequencies.

[0108] Specifically, the zero point of the initial frequency equation shown in formula (17) is a -∞ singular point in the target frequency equation. Since the theoretical zero point (the singular point of the target frequency equation) cannot usually be reached when numerical solution is used, there will be no problem of no functional meaning in formula (18) during the solution process.

[0109] After solving the target frequency equation using the peak finding function findpeaks, such as Figure 3 As shown, a target frequency equation curve can be obtained, where the abscissa of the target frequency equation curve is the frequency, and the ordinate is the corresponding function value.

[0110] based on Figure 3A plurality of local minima in the concerned frequency band (which can be understood as the target frequency band) can be obtained, and the plurality of local minima are the corresponding natural frequencies.

[0111] S113, determining the undetermined coefficients of the shape function according to the natural frequency, substituting the undetermined coefficients into the shape function of the corresponding compartment to obtain the full arrow vibration shape.

[0112] Through the above step S112, the natural frequency ω of the whole arrow can be obtained. 1 ,ω 2 ,ω 3 ......, for the i-th order natural frequency ω i , will ω i Back to the coefficient matrix to get A(ω i ).

[0113] Solve for the i-th order natural frequency ω i The corresponding vibration mode is to solve the expression of each shape function of equation (6) at the natural frequency. Since the i-th order natural frequency ω i It has been found that β in formula (6) 1 , β 2 ...β m According to the corresponding ω 1 ,ω 2 ,ω 3 ...... calculated. Then we need to further solve the unknown coefficients, that is, we need to solve the coefficient vector in formula (16)

[0114] Since the i-th order natural frequency ω i For approximate solution, it does not strictly satisfy formula (16). If the frequency step size selected when solving the local minimum is very small (for example, 0.001 Hz, 0.001 Hz = 0.002πrad / s), it can ensure that formula (16) is approximately satisfied, that is, we get:

[0115]

[0116] In formula (19), is approximately a non-zero solution of formula (19), It can also be considered as A(ω i ) is approximately 0. Therefore, we solve The process can be transformed into calculating A(ω i )'s eigenvalues ​​and eigenvectors.

[0117] In one embodiment, determining the undetermined coefficients of the shape function according to the natural frequency includes:

[0118] Substituting the i-th natural frequency into the coefficient matrix yields A(ω i ) value;

[0119] determining a plurality of initial eigenvalues ​​and a plurality of initial eigenvectors of a coefficient matrix;

[0120] Determining a target eigenvalue from a plurality of initial eigenvalues ​​and determining a first target eigenvector corresponding to the target eigenvalue;

[0121] Each value in the first target feature vector is determined as the undetermined coefficient of the shape function.

[0122] Specifically, the i-th order natural frequency ω i are all known, so the i-th order natural frequency ω i Substitute into the coefficient matrix A(ω i ), at this time A(ω i ) are all known elements.

[0123] Then we can solve A(ω i )’s initial eigenvalue λ 1 , 2 ... 4m and the initial eigenvector v 1 、v 2 ...v 4m There are many eigenvalues ​​and eigenvectors. The present invention needs to screen out qualified target eigenvalues ​​and eigenvectors corresponding to the target eigenvalues ​​from multiple initial eigenvalues.

[0124] In one embodiment, determining a target eigenvalue from a plurality of initial eigenvalues ​​and determining a first target eigenvector corresponding to the target eigenvalue includes:

[0125] If it is determined that the modulus of the smallest eigenvalue among the multiple initial eigenvalues ​​differs from the modulus of the remaining eigenvalues ​​by at least one or more orders of magnitude, the smallest eigenvalue is determined as the target eigenvalue;

[0126] The eigenvector corresponding to the target eigenvalue is determined as the first target eigenvector.

[0127] For example, suppose the magnitude of the smallest eigenvalue is 10 -4 , the magnitude of the remaining eigenvalues ​​is of the order of 10 -2 In this case, it means that there is only one target eigenvalue. The minimum eigenvalue can be directly determined as the target eigenvalue, and the eigenvector corresponding to the target eigenvalue can be determined as the first target eigenvector. The first target eigenvector is The particular solution of , that is, the first target eigenvector, is the unknown coefficient of the corresponding shape function in the above formula (6).

[0128] Assume that the first target feature vector is the kth initial feature vector v k In order to obtain the orthogonal normalized vibration mode, it is also necessary to calculate the normalization coefficient a according to formula (20):

[0129]

[0130] In formula (20), n is the cabin number, m is the total number of cabins, To transform the first target feature vector v k Substitute into formula (6) to obtain the shape function of the nth compartment (n = 1, 2, 3, ..., m); ρ n is the equivalent linear density of the nth compartment, l n is the length of the nth compartment.

[0131] Then, the first target feature vector is orthogonally normalized according to formula (21) to obtain the orthogonally normalized

[0132]

[0133] The obtained value in formula (21) Substituting into the corresponding shape function in formula (6), the first normalized vibration mode of the whole arrow can be obtained.

[0134] In another embodiment, determining a target eigenvalue from a plurality of initial eigenvalues ​​and determining a first target eigenvector corresponding to the target eigenvalue includes:

[0135] determining a minimum eigenvalue from a plurality of initial eigenvalues;

[0136] If it is determined that there is at least one reference eigenvalue in the remaining eigenvalues ​​whose modulus is at the same order of magnitude as the minimum eigenvalue, the minimum eigenvalue and the reference eigenvalue are used to determine the target eigenvalue;

[0137] The eigenvector corresponding to the target eigenvalue is determined as the first target eigenvector.

[0138] For example, suppose the magnitude of the smallest eigenvalue is 10 -4 , there is a first residual eigenvalue whose modulus is of the order of 10 -4, in this case, it means that the first target eigenvalue includes two. The minimum eigenvalue and the first remaining eigenvalue can be directly determined as the target eigenvalue, and the eigenvector corresponding to the target eigenvalue can be determined as the first target eigenvector. Then, each first target eigenvector is substituted into the undetermined coefficient of formula (6), and the second target eigenvector orthogonal to stiffness and mass is calculated by Schmidt orthogonalization method, and then the second full-arrow normalized vibration shape is determined according to the same method as above based on formula (20)(21) and formula (6). The number of the first full-arrow normalized vibration shapes is the same as the number of the first target eigenvectors.

[0139] It should be noted that, in this case, the number of the second full-arrow normalized vibration modes and the number of the second target eigenvectors are also the same.

[0140] In this way, the embodiment of the present invention first determines the shape function corresponding to each compartment according to the dynamic model of the rocket compartment, and at this time, the shape function still has unknown undetermined coefficients; then, the frequency equation can be determined according to the shape function of each compartment, the free boundary conditions at both ends of the rocket, and the boundary equations connecting the compartments, and then the frequency equation is solved to obtain the natural frequency required by the mode; the natural frequency is back-substituted into the coefficient matrix to determine the final eigenvalue and eigenvector, and each value in the eigenvector is the value of the undetermined coefficient of the shape function. Finally, the value in the undetermined coefficient is substituted into the corresponding shape function to obtain the full arrow vibration mode required by the mode; in this way, the rocket mode can be preliminarily determined in the early stage of the development of the launch vehicle, thereby ensuring the design efficiency of the entire arrow body.

[0141] Based on the same inventive concept as in the above-mentioned embodiment, this embodiment also provides a device for determining the rocket mode, such as Figure 4 As shown, the device comprises:

[0142] A first determining unit 41 is used to determine the shape function corresponding to each rocket compartment according to the dynamics model of the rocket compartment;

[0143] The second determining unit 42 is used to determine the target frequency equation according to the shape function corresponding to each compartment, the free boundary conditions at both ends of the rocket and the boundary equations connecting the compartments;

[0144] A solving unit 43, used for solving the target frequency equation to obtain the natural frequency of the frequency band of interest;

[0145] The third determination unit 44 is used to determine the undetermined coefficients of the shape function according to the natural frequency, and substitute the undetermined coefficients into the shape function of the corresponding compartment to obtain the full arrow vibration shape.

[0146] Since the device introduced in the embodiment of the present invention is a device used to implement the method for determining the rocket mode of the embodiment of the present invention, based on the method introduced in the embodiment of the present invention, the person skilled in the art can understand the specific structure and deformation of the device, so it is not repeated here. All devices used in the method of the embodiment of the present invention belong to the scope of protection of the present invention.

[0147] Based on the same inventive concept, this embodiment provides a computer device, including a memory processor and a computer program stored in the memory and executable on the processor, and the processor implements any step of the method described above when executing the computer program.

[0148] Based on the same inventive concept, this embodiment provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of any of the methods described above are implemented.

[0149] Through one or more embodiments of the present invention, the present invention has the following beneficial effects or advantages:

[0150] The present invention provides a method, device, medium and equipment for determining rocket modes, the method comprising: determining the shape function corresponding to each compartment of the rocket according to the dynamic model of the rocket compartment; determining the target frequency equation according to the shape function corresponding to each compartment, the free boundary conditions at both ends of the rocket and the boundary equations connecting the compartments; solving the target frequency equation to obtain the natural frequency of the frequency band of interest; determining the undetermined coefficients of the shape function according to the natural frequency, substituting the undetermined coefficients into the shape function of the corresponding compartment to obtain the full arrow vibration mode; in this way, the shape function corresponding to each compartment is first determined according to the dynamic model of the rocket compartment, and the shape function at this time There are still unknown undetermined coefficients; then the frequency equation can be determined according to the shape function of each compartment, the free boundary conditions at both ends of the rocket and the boundary equations connecting the compartments, and then the frequency equation is solved to obtain the natural frequency required by the mode; the natural frequency is substituted back into the coefficient matrix to determine the final eigenvalue and eigenvector, and each value in the eigenvector is the value of the undetermined coefficient of the shape function. Finally, the value of the undetermined coefficient is substituted into the corresponding shape function to obtain the full arrow vibration shape required by the mode; in this way, in the early stage of launch vehicle development, the rocket mode can be quickly determined without a lot of complex work such as modeling, thereby ensuring the design efficiency of the entire rocket body.

[0151] The algorithm and display provided herein are not inherently related to any particular computer, virtual system or other device. Various general purpose systems can also be used together with the teachings based on this. According to the above description, it is obvious that the structure required for constructing such systems. In addition, the present invention is not directed to any specific programming language either. It should be understood that various programming languages ​​can be utilized to realize the content of the present invention described herein, and the description of the above specific languages ​​is for disclosing the best mode of the present invention.

[0152] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0153] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the intention that the claimed invention requires more features than those explicitly recited in each claim. More specifically, as reflected in the claims below, inventive aspects lie in less than all the features of the individual embodiments disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present invention.

[0154] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and in addition they may be divided into a plurality of submodules or subunits or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this manner may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0155] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims below, any one of the claimed embodiments may be used in any combination.

[0156] The various component embodiments of the present invention can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all functions of some or all components in a gateway, proxy server, or system according to an embodiment of the present invention. The present invention can also be implemented as a device or apparatus program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program implementing the present invention can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0157] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising a number of different elements and by means of a suitably programmed computer. In a unit claim enumerating a number of devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc., does not indicate any order. These words may be interpreted as names.

[0158] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0159] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for determining rocket mode, characterized in that: The method comprises: Determine the shape function corresponding to each section of the rocket based on the dynamic model of the rocket section; Determine the target frequency equation according to the shape function corresponding to each compartment, the free boundary conditions at both ends of the rocket and the boundary equations connecting the compartments; Solving the target frequency equation to obtain the natural frequency of the frequency band of interest; The undetermined coefficients of the shape function are determined according to the natural frequency, and the undetermined coefficients are substituted into the shape function of the corresponding compartment to obtain the full arrow vibration shape.

2. The method according to claim 1, characterized in that The determining of the frequency equation according to the shape function corresponding to each compartment, the free boundary conditions at both ends of the rocket and the boundary equations connecting the compartments includes: According to the free boundary conditions at both ends of the rocket, the shape function corresponding to the first compartment is subjected to second-order and third-order derivatives, and the shape function corresponding to the last compartment is subjected to second-order and third-order derivatives, to obtain a first boundary equation group; the first boundary equation group contains undetermined coefficients of the corresponding shape function; Processing the shape functions of the intermediate compartments according to the boundary equations of the connection between the compartments to obtain a second set of boundary equations; the second set of boundary equations contains undetermined coefficients corresponding to the shape functions; Extract the undetermined coefficients from the first boundary equation group and the second boundary equation group to obtain the undetermined coefficient vector A coefficient matrix A(ω) is constructed based on the remaining parameters in the first boundary equation group and the second boundary equation group; wherein, according to Determine that the determinant value of the coefficient matrix A(ω) is 0. When the determinant value of the coefficient matrix A(ω) is 0, the initial frequency equation is f(ω)=det(A(ω))=0; A target frequency equation is determined according to the initial frequency equation.

3. The method according to claim 2, characterized in that The step of determining the target frequency equation according to the initial frequency equation comprises: The target frequency equation g(ω) is determined according to the formula g(ω)=lg(|f(ω)|).

4. The method according to claim 1, characterized in that The step of solving the target frequency equation to obtain the natural frequency of the frequency band of interest includes: A peak search function is used to search for multiple local minima on a curve corresponding to the target frequency equation; and the multiple local minima are determined as the natural frequencies.

5. The method according to claim 1, characterized in that The determining of the undetermined coefficients of the shape function according to the natural frequency comprises: Substituting the i-th natural frequency into the coefficient matrix yields A(ω i ) value; Determining a plurality of initial eigenvalues ​​and a plurality of initial eigenvectors of the coefficient matrix; Determining a target eigenvalue from the multiple initial eigenvalues ​​and determining a first target eigenvector corresponding to the target eigenvalue; Each value in the first target feature vector is determined as an undetermined coefficient of the shape function.

6. The method according to claim 5, characterized in that The step of determining a target eigenvalue from the multiple initial eigenvalues ​​and determining a first target eigenvector corresponding to the target eigenvalue comprises: If it is determined that the modulus of the minimum eigenvalue among the multiple initial eigenvalues ​​differs from the modulus of the remaining eigenvalues ​​by at least one or more orders of magnitude, the minimum eigenvalue is determined as the target eigenvalue; A feature vector corresponding to the target feature value is determined as the first target feature vector.

7. The method according to claim 5, characterized in that The step of determining a target eigenvalue from the multiple initial eigenvalues ​​and determining a first target eigenvector corresponding to the target eigenvalue comprises: determining a minimum eigenvalue from the plurality of initial eigenvalues; If it is determined that there is at least one reference eigenvalue in the remaining eigenvalues ​​whose modulus is at the same order of magnitude as the minimum eigenvalue, the minimum eigenvalue and the reference eigenvalue are used to determine the target eigenvalue; A feature vector corresponding to the target feature value is determined as the first target feature vector.

8. A device for determining rocket mode, characterized in that: The device comprises: A first determining unit is used to determine a shape function corresponding to each rocket compartment according to a dynamics model of the rocket compartment; A second determination unit is used to determine a target frequency equation according to a shape function corresponding to each compartment, free boundary conditions at both ends of the rocket, and a boundary equation connecting the compartments; A solving unit, used for solving the target frequency equation to obtain the natural frequency of the frequency band of interest; The third determination unit is used to determine the undetermined coefficients of the shape function according to the natural frequency, and substitute the undetermined coefficients into the shape function of the corresponding compartment to obtain the full arrow vibration shape.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

10. 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 program, the steps of the method according to any one of claims 1 to 7 are implemented.

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