A posture-thermal coupling optimization design system and method

Abstract

The present invention relates to the field of spacecraft attitude control, and particularly to a coupled attitude and thermal optimization design system and method. The system includes: a software interface module, which provides an interface for the automatic operation of the thermal control analysis software; a satellite thermal model, which establishes a satellite thermal analysis model on the thermal control analysis software according to the known input conditions of the satellite and the assumed attitude values; a conjugate gradient calculation module, which inversely calculates the solar vector of the inertial orientation attitude by using the conjugate gradient method based on the target temperature field and the temperature field calculated by the actually received satellite thermal model; the software interface module receives the calculated attitude data, transfers the attitude data to the thermal control analysis software, initializes it and starts the analysis software; obtains the temperature field result calculated by the thermal control analysis software, and feeds back the temperature field result to the conjugate gradient calculation module. Under the condition of a known target temperature field, the solar vector of the inertial orientation attitude is inversely designed by the conjugate gradient method, so as to control the attitude and temperature of the whole satellite to meet the requirements simultaneously.

Description

Technical Field

[0001] The present invention relates to the field of spacecraft attitude control, and particularly to a coupled attitude-thermal optimization design system and method. Background Art

[0002] When a satellite detects a target, the satellite attitude is sometimes inertial orientation. During inertial orientation, the position of the solar vector is generally relatively fixed. In some special cases, the satellite observes in inertial orientation throughout the orbit. At this time, the temperature field of some satellites in the inertial orientation mode may exceed the required range. To determine a suitable inertial orientation attitude, the general method is to give discrete attitude data of the target, but this method requires a large amount of attitude data and may not be able to fully screen out the observations that meet the thermal control requirements. Summary of the Invention

[0003] The present invention provides a coupled attitude-thermal optimization design system and method, aiming to reverse the requirements for the satellite attitude through coupled attitude-thermal design to meet the attitude form required by thermal control.

[0004] The present invention provides a coupled attitude-thermal optimization design system, including:

[0005] A software interface module: providing an interface for the automatic operation of the thermal control analysis software;

[0006] A satellite thermal model: establishing a satellite thermal analysis model on the thermal control analysis software according to the known input conditions such as the current overall layout, heat dissipation, and working mode of the satellite and the attitude assumed values;

[0007] A conjugate gradient calculation module: inversely calculating the solar vector of the inertial orientation attitude by using the conjugate gradient method according to the target temperature field and the temperature field calculated by the actually received satellite thermal model;

[0008] The software interface module receives the attitude data calculated by the conjugate gradient calculation module, transfers the attitude data to the thermal control analysis software, initializes the thermal control analysis software and starts the analysis software; obtains the temperature field result calculated by the thermal control analysis software, and feeds back the temperature field result to the conjugate gradient calculation module.

[0009] As a further improvement of the present invention, the operation process of the conjugate gradient calculation module includes:

[0010] Assume that the solar vectors in the satellite body coordinates during inertial orientation attitude are P1, P2, and P3, where P3 is determined by P1 and P2, the earth vector takes the value corresponding to the initial attitude, and the attitude vector is:

[0011] P T =[P1, P2] (1)

[0012] Define the function S

[0013] S(P) = [Y - T(P)] T [Y - T(P)] (2)

[0014] where Y is the target value of the satellite temperature field, and T(P) is the temperature field of the satellite under the P attitude vector;

[0015] The goal is to find the minimum value of the function S

[0016]

[0017] As a further improvement of the present invention, in each iteration process of the conjugate gradient calculation module, a new inertial orientation attitude solar vector is obtained according to conditions including the target temperature field, the temperature field calculated from the actually received satellite thermal model, and the temperature change gradient of the satellite thermal model:

[0018] P k+1 = P k - β k d k (4)

[0019] where β k is the search step size, and d k is the descent direction;

[0020]

[0021] where γ k is the conjugate coefficient;

[0022]

[0023]

[0024]

[0025]

[0026] The present invention provides a method for attitude-thermal coupling optimization design, including the following steps:

[0027] S1. Set the initial attitude solar vector as P 0 , and define k = 0;

[0028] S2. The software interface module transfers the initial attitude solar vector P 0 to the satellite thermal model, and starts the thermal model in the thermal analysis software to solve the satellite temperature field at the P k attitude, obtaining T(P k );

[0029] S3. The software interface module transfers T(P k)Feed it back to the conjugate gradient calculation module, and the conjugate gradient calculation module determines whether to converge according to the convergence criterion S(P k+1 ) < ε. If it converges, stop the correction process and calculate the complete attitude data that satisfies the solar vector as P k . Then, transmit the attitude data to the thermal model through the software interface module to calculate the final satellite temperature field; if it does not converge, continue with step S4;

[0030] S4. Calculate the parameter conditions: Solve the temperature field gradient at the P k attitude P k function gradient at the attitude conjugate coefficient γ k , descent direction d k , search step size β k ;

[0031] S5. Obtain the new attitude solar vector P k+1 according to the parameter conditions in step S4, and change the solar vector in the satellite thermal model attitude data;

[0032] S6. Define k = k + 1, and return to execute step S2.

[0033] As a further improvement of the present invention, in step S4 is numerically solved by the finite difference method.

[0034] As a further improvement of the present invention, the conjugate coefficient γ k in step S4 is calculated by the following equation:

[0035]

[0036] As a further improvement of the present invention, the descent direction d k in step S4 is calculated by the following equation:

[0037]

[0038] As a further improvement of the present invention, the search step size β k in step S4 is calculated by the following equation:

[0039]

[0040] where

[0041]

[0042] As a further improvement of the present invention, the new attitude solar vector P k+1 in step S5 is calculated by the following equation:

[0043] P k+1 = P k -β k d k 。

[0044] The beneficial effects of the present invention are as follows: Under the condition of a known target temperature field, the solar vector of the inertial orientation attitude is inversely designed by the conjugate gradient method, so as to control the attitude and temperature of the whole satellite to meet the requirements simultaneously. This method can inversely design the attitude requirements according to the target temperature field, reduce the thermal analysis amount during the forward input of the attitude, and enhance the constraint on the flight attitude of the satellite. Brief Description of the Drawings

[0045] Figure 1 is a schematic diagram of the modules of the attitude-thermal coupling optimization design system of the present invention;

[0046] Figure 2 is the solar vector diagram in the satellite body coordinate system of the present invention. Specific Embodiments

[0047] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0048] As Figure 1 shown, an attitude-thermal coupling optimization design system of the present invention includes the following functional modules:

[0049] Software Interface Module:

[0050] The interface software provides an interface for the automatic operation of the thermal control analysis software. The main functions of the interface software are as follows: receiving the attitude data calculated by the conjugate gradient calculation module, transmitting the attitude data to the thermal control analysis software, initializing the thermal control analysis software and starting the analysis software; obtaining the temperature field results calculated by the thermal control analysis software and feeding back the temperature field results to the conjugate gradient calculation module.

[0051] Satellite Thermal Model:

[0052] According to the known input conditions such as the current overall layout, heat dissipation, working mode, etc. of the satellite and the attitude assumed values, a satellite thermal analysis model is established on the thermal control analysis software.

[0053] Conjugate Gradient Calculation Module:

[0054] According to the target temperature field and the temperature field calculated by the actually received satellite thermal model, the solar vector of the inertial orientation attitude is inversely calculated by the conjugate gradient method. The calculation principle is as follows:

[0055] As Figure 2As shown in the figure, when setting the inertial orientation attitude, the solar vectors in the satellite body coordinates are P1, P2, and P3. P3 can be determined by P1 and P2. Since the influence of the earth on the satellite temperature field is relatively small, the earth vector is taken as the value corresponding to the initial attitude.

[0056] The attitude vector is:

[0057] P T = [P1, P2] (1)

[0058] Define the S function

[0059] S(P) = [Y - T(P)] T [Y - T(P)] (2)

[0060] where Y is the target value of the satellite temperature field, and T(P) is the satellite temperature field under the P attitude vector.

[0061] The goal is to find the minimum value of the S function

[0062]

[0063] In each iteration process of the conjugate gradient calculation module, according to conditions such as the target temperature field, the temperature field calculated based on the actually received satellite thermal model, and the temperature change gradient of the satellite thermal model, a new inertial orientation attitude solar vector is obtained:

[0064] P k+1 = P k -β k d k (4)

[0065] where β k is the search step size, and d k is the descent direction.

[0066]

[0067] where γ k is the conjugate coefficient

[0068]

[0069]

[0070]

[0071]

[0072] A method for coupled attitude and thermal optimization design of the present invention includes the following steps:

[0073] S1. Assume that the initial attitude solar vector is P 0 , and define k = 0.

[0074] S2. The software interface module transfers the initial attitude solar vector P 0 to the satellite thermal model and starts the solution of the thermal model in the thermal analysis software for P k the satellite temperature field at the attitude to obtain T(P k ).

[0075] S3. The software interface module feeds back T(P k ) to the conjugate gradient calculation module. The conjugate gradient calculation module determines whether to converge according to the convergence criterion S(P k+1 ) < ε. If it converges, the correction process is stopped, and the complete attitude data satisfying the solar vector P k is calculated and transferred to the thermal model through the software interface module to calculate the final satellite temperature field; if it does not converge, continue with step S4; where ε is the sum of the target value of the satellite temperature field and the standard deviation of the actually calculated temperature field, that is the standard deviation is set according to the accuracy requirements.

[0076] S4. Calculate the parameter conditions: solve the temperature field gradient at the P k attitude P k the S function gradient at the attitude the conjugate coefficient γ k , the descent direction d k , and the search step size β k .

[0077] Among them, since the solution of the temperature field by this thermal model is non-linear it cannot be directly obtained and is approximately solved by the finite difference numerical method.

[0078] The calculation equation for the conjugate coefficient γ k is as follows:[[]]

[0079]

[0080] The calculation equation for the descent direction d k is as follows:[[]]

[0081]

[0082] The calculation equation for the search step size β k is as follows:[[]]

[0083]

[0084] Among them

[0085]

[0086] S5. Obtain the new attitude solar vector P according to the parameter conditions in step S4 k+1 , and change the solar vector in the attitude data of the satellite thermal model.

[0087] S6. Define k = k + 1, and return to execute step S2.

[0088] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can also be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A posture-thermal coupling optimization design system, characterized in that Including: Software interface module: Provides an interface for the automatic operation of the thermal control analysis software. Satellite thermal model: Based on the current overall layout, heat dissipation, known input conditions of the working mode, and attitude assumption values of the satellite, a satellite thermal model is established on the thermal control analysis software. The satellite thermal model is used to perform parameter correction on the solar vector after attitude update. Conjugate gradient calculation module: According to the target temperature field and the temperature field calculated by the actually received satellite thermal model, the solar vector of the inertial orientation attitude is inversely calculated using the conjugate gradient method. The software interface module receives the attitude data calculated by the conjugate gradient calculation module, transfers the attitude data to the thermal control analysis software, initializes the thermal control analysis software, and starts the analysis software. Obtain the temperature field result calculated by the thermal control analysis software and feedback the temperature field result to the conjugate gradient calculation module. The operation process of the conjugate gradient calculation module includes: Assume that the solar vectors in the satellite body coordinates at the inertial orientation attitude are P1, P2, and P3, where P3 is determined by P1 and P2, the earth vector takes the value corresponding to the initial attitude, and the attitude vector is: P T = [P1, P2] (1) Define the function S S(P) = [Y - T(P)] T [Y - T(P)] (2) where Y is the target value of the satellite temperature field, and T(P) is the temperature field of the satellite under the P attitude vector. The goal is to find the minimum value of the function S In each iteration process of the conjugate gradient calculation module, a new solar vector of the inertial orientation attitude is obtained according to conditions including the target temperature field, the temperature field calculated by the actually received satellite thermal model, and the temperature change gradient of the satellite thermal model: P k+1 = P k - β k d k (4) Among them, β k is the search step size, and d k is the descent direction; where γ k is the conjugate coefficient; 2. A posture-thermal coupling optimization design method, characterized in that Including the following steps: S1. Set the initial attitude solar vector as P 0 , define k = 0; S2. The software interface module transfers the initial attitude solar vector P 0 to the satellite thermal model and starts the solution of the satellite thermal model in the thermal control analysis software for the satellite temperature field at the attitude P k to obtain T(P k ); S3. The software interface module feeds T(P k ) back to the conjugate gradient calculation module. The conjugate gradient calculation module determines whether to converge according to the convergence criterion S(P k+1 ) < ε. If it converges, the correction process is stopped, and the complete attitude data satisfying the solar vector as P k is calculated. The attitude data is transmitted to the satellite thermal model through the software interface module to calculate the final satellite temperature field; if it does not converge, continue with step S4; S4. Calculation parameter conditions: Solve for P k Temperature field gradient function in the attitude P k Gradient of the S function in the attitude Conjugate coefficient γ k , Descent direction d k , Search step size β k ; S5. Obtain the new attitude solar vector P according to the parameter conditions in step S4 k+1 , and change the solar vector in the satellite thermal model attitude data; S6. Define k = k + 1 and return to execute step S2; In the said step S4 obtained by numerically solving using the finite difference method; The conjugate coefficient γ in the step S4 k has the following calculation equation: The descending direction d in the step S4 k has the following calculation equation: The search step size β in the step S4 k has the following calculation equation: Among them 3. The posture-thermal coupling optimization design method according to claim 2, wherein The calculation equation for the new attitude solar vector P in the step S5 k+1 is as follows: P k+1 = P k - β k d k 。

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