A method for calculating flight atmospheric parameters based on state uniqueness

Abstract

This invention discloses a method for calculating flight atmospheric parameters based on state uniqueness, belonging to the field of aerospace technology. It is applicable to the calculation of flight atmospheric parameters for flying-wing aerodynamic configuration aircraft. The method calculates the local Mach number based on the pressure values ​​from five embedded atmospheric data sensors. From the local Mach number, all possible combinations of angle of attack and sideslip angle are obtained, along with the corresponding angle-of-attack pressure coefficient, sideslip pressure coefficient, static pressure, total pressure, and Mach number for each combination. By comparing the static pressure, total pressure, and Mach number under each angle-of-attack and sideslip angle state, combinations within a threshold range represent the angle of attack, sideslip angle, static pressure, total pressure, and Mach number under actual flight conditions. This method provides highly reliable atmospheric data parameters for various flying-wing aerodynamic configuration aircraft, is not limited by the aircraft's aerodynamic shape or pressure altitude, can determine a unique solution from multiple combinations, ensures the correctness of parameter calculation, avoids non-convergence issues, and has universal applicability.

Description

Technical Field

[0001] This invention belongs to the field of aerospace technology, specifically relating to a method for calculating atmospheric parameters of flight based on state uniqueness, used to calculate the air pressure altitude, Mach number, airspeed, angle of attack, and sideslip angle parameters of a flying wing aerodynamic layout aircraft throughout the entire flight process. Background Technology

[0002] Due to its advantages such as good aerodynamic characteristics, minimal impact on overall aircraft performance, low radar cross-section (RCS), good stealth performance, and effective reduction of aerodynamic heat, flying wing aerodynamic layout technology has been widely used in the aerodynamic design of aircraft and hypersonic weapons. Embedded atmospheric data sensor systems, conformally designed and installed on the aircraft surface, not only do not affect the overall aerodynamic and stealth performance of the aircraft, but also provide redundant atmospheric data such as pressure altitude, Mach number, airspeed, angle of attack, and sideslip angle through multi-sensor arrays. Embedded atmospheric data sensor systems are the optimal solution for atmospheric data measurement in flying wing aerodynamic layout aircraft.

[0003] The X-33 spaceplane's embedded atmospheric data system uses cross-shaped embedded atmospheric data sensors positioned at the front of a blunt-nosed body to collect flight pressure. It accurately obtains flight atmospheric data using the three-point method and least squares method based on the airflow angle of the blunt-nosed body and the circumferential angle of the pressure measuring holes. The X-43A hypersonic aircraft obtains its angle of attack and sideslip angle values ​​by relating the pressure difference between pressure measuring holes symmetrically arranged on the upper and lower wedge-shaped surfaces of the fuselage to the flight state. It obtains total pressure and static pressure through the pressure measuring holes at the foremost and edge of the wedge-shaped surfaces. However, the B-2 and X-47B aircraft employ a blended wing-body aerodynamic layout. Their embedded atmospheric data systems do not follow the blunt-nosed body shape and wedge-shaped pressure measuring hole layout. Therefore, the three-point method, least squares method, and upper and lower pressure difference cannot guarantee the accuracy of flight atmospheric data calculation. Their high-precision, high-reliability atmospheric data calculation methods have not been publicly disclosed.

[0004] Patents CN201410584791.7 and US6253166B1 disclose a method that uses pressure sensing holes arranged in a cross shape at the front end of a blunt-nosed body to obtain atmospheric data such as barometric altitude, Mach number, angle of attack, and sideslip angle that can meet the accuracy requirements for aircraft use through the three-point method and the least squares method. However, this method is not applicable to flying wing aerodynamic layout aircraft.

[0005] The total pressure, static pressure, angle-of-attack pressure coefficient, and sideslip angle pressure coefficient disclosed in the embedded atmospheric data system for flying wing aerodynamic layout aircraft disclosed in patent GB2424285A are only applicable to constant flight speed and constant flight altitude, and cannot meet the atmospheric data usage requirements of the entire flight envelope.

[0006] Patent GB2432914A discloses that atmospheric data such as total pressure, static pressure, Mach number, angle of attack, and sideslip angle in an embedded atmospheric data system for flying wing aerodynamic aircraft are obtained through a neural network algorithm. Although the neural network algorithm has a strong nonlinear fitting ability, it has the defect of the error performance function getting trapped in a local minimum. Furthermore, an inappropriate number of hidden layer neurons may lead to underfitting or overfitting of the network. In addition, the selection of the learning rate lacks theoretical guidance. Simply relying on the atmospheric data obtained by the neural network algorithm cannot guarantee the accuracy of the atmospheric data within the entire flight envelope of the aircraft.

[0007] In summary, during the entire flight process of an aircraft, the atmospheric data such as pressure altitude, Mach number, angle of attack, and sideslip angle provided by the embedded atmospheric data sensor system are key factors for controlling and guiding the accurate execution of the aircraft's mission and ensuring safe flight. The mathematical model for calculating atmospheric data by the embedded atmospheric data sensor system should be applicable to the entire flight process. The atmospheric data such as pressure altitude, Mach number, angle of attack, and sideslip angle calculated based on the pressure change law within the entire flight envelope can ensure the flight safety of the aircraft and improve the reliability of the system mission. However, in the existing technology, there is no method for calculating flight atmospheric parameters that can achieve the above objectives. Summary of the Invention

[0008] In view of the above-mentioned shortcomings in the prior art, the flight atmospheric parameter calculation method based on state uniqueness provided by the present invention solves the problems in the background art.

[0009] To achieve the aforementioned objectives, the present invention employs the following technical solution: a method for calculating flight atmospheric parameters based on state uniqueness, applicable to the calculation of flight atmospheric parameters for flying wing aerodynamic configuration aircraft, comprising the following steps:

[0010] S1. Through CFD simulation, construct numerical tables of local Mach number, angle-of-attack pressure coefficient, sideslip pressure coefficient, and hydrostatic pressure coefficient within the preset angle of attack and sideslip angle range for different real Mach numbers.

[0011] S2. The pressure values ​​under various flight attitudes are collected by five embedded atmospheric data sensors that are conformally mounted to the surface of the flying wing aerodynamic layout aircraft, and the local Mach number is calculated.

[0012] S3. Based on the local Mach number, obtain all the true Mach numbers, angle of attack and sideslip angle combination states by looking up the table, as well as the angle of attack pressure coefficient, sideslip angle pressure coefficient and static pressure coefficient corresponding to each combination state;

[0013] S4. Based on the angle-of-attack pressure coefficient and sideslip angle pressure coefficient under each combination state, calculate the corresponding total pressure and static pressure, and obtain several candidate atmospheric parameter combinations by combining them with the actual Mach number.

[0014] S5. Determine whether the total pressure, static pressure and true Mach number in each combination of atmospheric parameters are all valid.

[0015] If so, the effective atmospheric parameter combination is output, including angle of attack, sideslip angle, total pressure, static pressure and true Mach number, to obtain a unique atmospheric parameter solution for the flight state;

[0016] If not, return to step S2.

[0017] Furthermore, in step S2, the installation method of the five embedded atmospheric data sensors is as follows:

[0018] Three embedded atmospheric data sensors are installed on the upper fuselage surface of the flying wing aerodynamic layout aircraft, and the pressure values ​​they collect are P1, P2 and P4 respectively. The other two embedded atmospheric data sensors are installed on the lower fuselage surface of the flying wing aerodynamic layout aircraft, P3 and P5.

[0019] Furthermore, in step S2, the method for calculating the local Mach number is specifically as follows:

[0020] S21. Determine whether the pressure values ​​collected by the five embedded atmospheric data sensors conformally mounted to the surface of the flying wing aerodynamic layout aircraft under each flight attitude are within the effective range.

[0021] If so, proceed to step S22;

[0022] If not, proceed to step S23;

[0023] S22. Calculate the local Mach number based on the collected pressure values;

[0024] S23. Continuously collect pressure values ​​under various flight attitudes and return to step S21;

[0025] Wherein, the local Mach number The calculation formula is:

[0026]

[0027] In the formula, This represents the minimum of the five pressure values ​​collected, i.e., static pressure. This represents the maximum value among the five pressure values ​​collected, i.e., the total pressure.

[0028] Furthermore, in step S4, the corresponding total pressure and static pressure are calculated by combining the calculation formulas for the angle of attack pressure coefficient and the sideslip angle pressure coefficient;

[0029] Among them, the angle of attack pressure coefficient and the pressure coefficient of the sliding angle The calculation formulas are as follows:

[0030]

[0031]

[0032] In the formula, P1, P2, and P4 represent the pressure values ​​collected by three embedded atmospheric data sensors installed on the upper fuselage surface of the flying wing aerodynamic layout aircraft, and P3 and P5 represent the pressure values ​​collected by two embedded atmospheric data sensors installed on the lower fuselage surface of the flying wing aerodynamic layout aircraft.

[0033] Furthermore, in step S5, the method for determining whether the true Mach number in each candidate atmospheric parameter combination is valid is as follows:

[0034] Determine whether the difference between the true Mach number and the threshold Mach number is within the allowable error range;

[0035] If so, then the true Mach number is valid;

[0036] If not, the true Mach number is invalid, and its corresponding candidate atmospheric parameter combination is eliminated.

[0037] Furthermore, the method for determining the threshold Mach number is as follows:

[0038] The total pressure and static pressure obtained by combining the formulas for calculating the pressure coefficient at the angle of attack and the pressure coefficient at the sideslip angle are substituted into the formula for calculating the local Mach number to obtain the threshold Mach number.

[0039] Furthermore, in step S5, the method for determining whether static pressure and total pressure are valid among candidate atmospheric parameter combinations with effective true Mach numbers is as follows:

[0040] Substitute the pressure values ​​collected by any two embedded atmospheric data sensors into the static pressure coefficient calculation formula to calculate the threshold static pressure and threshold total pressure at this time.

[0041] Determine whether the differences between the threshold static pressure and the threshold total pressure and the static pressure and total pressure obtained by combining the formulas for calculating the pressure coefficient of the angle of attack and the pressure coefficient of the sideslip angle are all within the allowable error range;

[0042] If so, then both the calculated static pressure and total pressure are valid;

[0043] If not, the calculated static pressure and / or total pressure are invalid, and the corresponding candidate atmospheric parameter combinations are discarded.

[0044] Furthermore, the formula for calculating the static pressure coefficient is as follows:

[0045]

[0046] In the formula, Indicates the threshold static pressure. Indicates the threshold full pressure. This represents the pressure values ​​collected by five embedded atmospheric data sensors.

[0047] The beneficial effects of this invention are as follows:

[0048] (1) The method of the present invention can provide highly reliable atmospheric data parameters for various flying wing aerodynamic layout aircraft, without being limited by the aerodynamic shape of the aircraft.

[0049] (2) In the process of atmospheric parameter calculation, the method of the present invention uses simple subtraction and division to construct the calculation formulas for the angle of attack pressure coefficient and sideslip pressure coefficient, which are not affected by air pressure altitude.

[0050] (3) The method of the present invention utilizes the uniqueness of Mach number, angle of attack, and sideslip angle states in flight to achieve multiple combinations The method determines a unique solution, which solves the problem that the total pressure, static pressure, angle of attack, and sideslip angle, which are necessary in the traditional atmospheric parameter calculation process, cannot be directly obtained and therefore cannot be used for atmospheric parameter calculation. It ensures the correctness of the parameter calculation, does not have the problem of non-convergence, and has universality. Attached Figure Description

[0051] Figure 1 This is a flowchart of the flight atmospheric parameter calculation method based on state uniqueness in this invention.

[0052] Figure 2 This is a schematic diagram of the installation of the embedded atmospheric data sensor in this invention. Detailed Implementation

[0053] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0054] This invention provides a method for calculating flight atmospheric parameters based on state uniqueness, applicable to the calculation of flight atmospheric parameters for flying wing aerodynamic configuration aircraft. In this method, the relationship between total pressure, static pressure, and Mach number of the flying wing aerodynamic configuration aircraft conforms to general aerodynamic distribution laws. The pressure values ​​collected by five embedded atmospheric data sensors conformally mounted to the surface of the flying wing aerodynamic configuration aircraft under various flight attitudes show a monotonically changing relationship with the incoming flow velocity, unaffected by pressure altitude. Specific relationships include:

[0055] At the same Mach number, the maximum pressure value on the upper surface of the fuselage and the minimum pressure value on the lower surface of the fuselage among the pressure values ​​collected by the five embedded atmospheric data sensors are strongly correlated with the angle of attack.

[0056] At the same Mach number, the maximum and minimum pressure values ​​of the displacement fuselage on the left and right sides among the pressure values ​​collected by the five embedded atmospheric data sensors are strongly correlated with the sideslip angle.

[0057] At the same Mach number, the static pressure coefficients of the pressure values ​​collected by the five embedded atmospheric data sensors change monotonically and linearly.

[0058] Based on this, the present invention provides a method for calculating flight atmospheric parameters based on state uniqueness, such as... Figure 1 As shown, it includes the following steps:

[0059] S1. Through CFD simulation, construct numerical tables of local Mach number, angle-of-attack pressure coefficient, sideslip pressure coefficient, and hydrostatic pressure coefficient within the preset angle of attack and sideslip angle range for different real Mach numbers.

[0060] S2. The pressure values ​​under various flight attitudes are collected by five embedded atmospheric data sensors that are conformally mounted to the surface of the flying wing aerodynamic layout aircraft, and the local Mach number is calculated.

[0061] S3. Based on the local Mach number, obtain all the true Mach numbers, angle of attack and sideslip angle combination states by looking up the table, as well as the angle of attack pressure coefficient, sideslip angle pressure coefficient and static pressure coefficient corresponding to each combination state;

[0062] S4. Based on the angle-of-attack pressure coefficient and sideslip angle pressure coefficient under each combination state, calculate the corresponding total pressure and static pressure, and obtain several candidate atmospheric parameter combinations by combining them with the actual Mach number.

[0063] S5. Determine whether the total pressure, static pressure and true Mach number in each combination of atmospheric parameters are all valid.

[0064] If so, the effective atmospheric parameter combination is output, including angle of attack, sideslip angle, total pressure, static pressure and true Mach number, to obtain a unique atmospheric parameter solution for the flight state;

[0065] If not, return to step S2.

[0066] In this embodiment of the invention, the "state uniqueness" in the above-mentioned atmospheric parameter calculation process means that there is a definite Mach number, angle of attack, and sideslip angle in any flight state. Based on this, because of the strong correlation between flight pressure and flight state, and the unique one-to-one correspondence between them, the determined flight state determines the unique total pressure and static pressure. Therefore, in this embodiment of the invention, the unique combination of atmospheric parameters in the determined flight state of the flying wing aerodynamic layout aircraft is calculated, including the one-to-one corresponding real Mach number, angle of attack, sideslip angle, static pressure, and total pressure.

[0067] In step S1 of this embodiment of the invention, after the layout of the pressure measurement holes of the flying wing aerodynamic layout aircraft is determined, a numerical table of local Mach number, angle-of-attack pressure coefficient, sideslip angle pressure coefficient and static pressure coefficient is constructed using known data obtained from CFD simulation and wind tunnel tests, under different real Mach numbers and within the range of preset angle of attack and sideslip angle, forming a database required for subsequent atmospheric parameter calculation.

[0068] In one example of this embodiment, the actual Mach numbers are 0.1, 0.3, 0.5, and 0.7, and the angle of attack is... The preset range is -8° to 16°, and the sideslip angle is... Taking a preset range of -12° to 12° as an example, at the angle of attack... and sideslip angle For every 2°, the corresponding local Mach number, angle of attack pressure coefficient, sideslip angle pressure coefficient, and hydrostatic pressure coefficient are calculated and a numerical table is generated, as shown in Tables 1 to 16 below.

[0069] In step S2 of this embodiment of the invention, as follows Figure 2 As shown, the installation method of the five embedded atmospheric data sensors is as follows:

[0070] Three embedded atmospheric data sensors are installed on the upper fuselage surface of the flying wing aerodynamic layout aircraft, and the pressure values ​​they collect are P1, P2 and P4 respectively. The other two embedded atmospheric data sensors are installed on the lower fuselage surface of the flying wing aerodynamic layout aircraft, P3 and P5.

[0071] In step S2 of this embodiment of the invention, the method for calculating the local Mach number is specifically as follows:

[0072] S21. Determine whether the pressure values ​​collected by the five embedded atmospheric data sensors conformally mounted to the surface of the flying wing aerodynamic layout aircraft under each flight attitude are within the effective range.

[0073] If so, proceed to step S22;

[0074] If not, proceed to step S23;

[0075] S22. Calculate the local Mach number based on the collected pressure values;

[0076] S23. Continuously collect pressure values ​​under various flight attitudes and return to step S21.

[0077] In this embodiment, the determination of the validity of the pressure values ​​collected by the embedded atmospheric data sensor under various flight attitudes includes two aspects: firstly, each pressure value needs to be within the allowable strategy range; secondly, the difference between any two pressure values ​​must be within the preset threshold range and the pressure change rate range. Only when both of the above conditions are met simultaneously can the collected pressure values ​​be determined to be valid.

[0078] In this embodiment, the validity of the pressure value is not affected by environmental changes. Under the determined pressure measurement hole layout, the criterion for the validity of the pressure value is unique for the flying wing aerodynamic layout aircraft.

[0079] Wherein, the local Mach number The calculation formula is:

[0080]

[0081] In the formula, This represents the minimum of the five pressure values ​​collected, i.e., static pressure. This represents the maximum value among the five pressure values ​​collected, i.e., the total pressure.

[0082] In step S3 of this embodiment, taking the numerical tables in Tables 1 to 16 as an example, assuming the local Mach number calculated by the above formula is 0.081, by looking up Tables 1 to 4, the local Mach number values ​​containing a local Mach number of 0.08 are found to be 0.081031 in Table 1 and 0.081896 in Table 2, with corresponding angle of attack and sideslip angle combinations of (8°, 12°) and (6°, 2°), respectively. Based on (8°, 12°) and (6°, 2°), the corresponding angle of attack pressure coefficient, sideslip angle pressure coefficient, and static pressure coefficient are found in the angle of attack pressure coefficient table (Tables 5 to 8), sideslip angle pressure coefficient table (Tables 9 to 12), and static pressure coefficient table (Tables 13 to 16), respectively.

[0083] In step S4 of this embodiment of the invention, based on the multiple angle-of-attack pressure coefficients and sideslip pressure coefficients found by looking up the table, the total pressure and static pressure corresponding to different angle-of-attack pressure coefficients and sideslip pressure coefficients are calculated by combining the calculation formulas of angle-of-attack pressure coefficients and sideslip pressure coefficients.

[0084] Among them, the angle of attack pressure coefficient and the pressure coefficient of the sliding angle The calculation formulas are as follows:

[0085]

[0086]

[0087] In the formula, P1, P2, and P4 represent the pressure values ​​collected by three embedded atmospheric data sensors installed on the upper fuselage surface of the flying wing aerodynamic layout aircraft, and P3 and P5 represent the pressure values ​​collected by two embedded atmospheric data sensors installed on the lower fuselage surface of the flying wing aerodynamic layout aircraft.

[0088] In this embodiment, Figure 2 In the diagram, P2 and P4 correspond to the embedded atmospheric data sensors installed on the left and right sides of the upper fuselage surface of the flying wing aerodynamic layout aircraft, P1 corresponds to the embedded atmospheric data sensor installed in the middle of the upper fuselage surface of the flying wing aerodynamic layout aircraft, and P3 and P5 correspond to the embedded atmospheric data sensors installed on the left and right sides of the lower fuselage surface of the flying wing aerodynamic layout aircraft. The positions of the embedded atmospheric data sensors corresponding to P3 and P2 are corresponding, and the positions of the embedded atmospheric data sensors corresponding to P5 and P4 are corresponding.

[0089] In step S5 of this embodiment, the method for determining whether the true Mach number in each candidate atmospheric parameter combination is valid is as follows:

[0090] Determine whether the difference between the true Mach number and the threshold Mach number is within the allowable error range;

[0091] If so, then the true Mach number is valid;

[0092] If not, the true Mach number is invalid, and its corresponding candidate atmospheric parameter combination is eliminated.

[0093] In this embodiment, the method for determining the threshold Mach number is as follows:

[0094] The total pressure and static pressure obtained by combining the formulas for calculating the pressure coefficient at the angle of attack and the pressure coefficient at the sideslip angle are substituted into the formula for calculating the local Mach number to obtain the threshold Mach number.

[0095] In one example of this embodiment, assuming the true Mach numbers in the candidate atmospheric parameter combinations include 0.1, 0.13, and 0.2, and the calculated threshold Mach number is 0.01 with an allowable error range of (-0.05, +0.05), then when determining whether the true Mach number is valid, the difference between the threshold Mach number and the true Mach number is calculated one by one. The difference with 0.1 is 0, with 0.13 it is 0.03, and with 0.2 it is 0.1. At this point, the true Mach number with a difference of 0.1 is not within the allowable error range, and its corresponding candidate atmospheric parameter combination needs to be removed, resulting in candidate atmospheric parameter combinations containing only true Mach numbers of 0.1 and 0.13.

[0096] For the candidate atmospheric parameter combinations obtained from the initial screening, although the true Mach number is valid, the static pressure and total pressure may not be valid, requiring further screening. Therefore, among the candidate atmospheric parameter combinations with valid true Mach numbers, the specific method for determining whether the static pressure and total pressure are valid is as follows:

[0097] Substitute the pressure values ​​collected by any two embedded atmospheric data sensors into the static pressure coefficient calculation formula to calculate the threshold static pressure and threshold total pressure at this time.

[0098] Determine whether the differences between the threshold static pressure and the threshold total pressure and the static pressure and total pressure obtained by combining the formulas for calculating the pressure coefficient of the angle of attack and the pressure coefficient of the sideslip angle are all within the allowable error range;

[0099] If so, then both the calculated static pressure and total pressure are valid;

[0100] If not, the calculated static pressure and / or total pressure are invalid, and the corresponding candidate atmospheric parameter combinations are deleted.

[0101] In this embodiment, the formula for calculating the static pressure coefficient is:

[0102]

[0103] In the formula, Indicates the threshold static pressure. Indicates the threshold full pressure. This represents the pressure values ​​collected by five embedded atmospheric data sensors.

[0104] Specifically, in this embodiment, any two collected pressure values ​​are substituted into the above static pressure coefficient calculation formula, and the threshold static pressure and threshold total pressure are solved simultaneously. These are then compared with the previously calculated static pressure and total pressure to filter out valid total pressure and static pressure. In one example of this embodiment, it is assumed that there are static pressure and total pressure combinations (0.5,2), (0.8,1), and (0.8,2). The threshold static pressure calculated by the above formula is 0.9, the threshold total pressure is 2.2, the allowable error range for static pressure is (-0.3,+0.3), and the allowable error range for total pressure is (-0.3,+0.3). Based on this, the above threshold static pressure and threshold total pressure are respectively compared with the static pressure and total pressure in the above combinations to obtain the static pressure coefficient. The pressure differences are 0.4, 0.1, and 0.1 respectively, and the differences with the total pressure are 0.2, 1.2, and 0.2 respectively. By comparing with the allowable error range, it is found that: the static pressure in (0.5,2) is invalid, while the total pressure is valid; the static pressure in (0.8,1) is valid, while the total pressure is invalid; and both the static pressure and the total pressure in (0.8,2) are valid. Therefore, in the above candidate atmospheric parameter combinations, only the static pressure and total pressure containing (0.8,2) are retained, and the other candidate atmospheric parameters can be deleted.

[0105] In this embodiment, among several candidate atmospheric parameter combinations obtained based on the aforementioned steps, a unique atmospheric parameter solution for the flight state is obtained through layer-by-layer screening using the actual Mach number, static pressure, and total pressure, including a one-to-one corresponding angle of attack. Sideslip angle Total pressure static pressure and the actual Mach number .

[0106] The method of this invention provides an atmospheric parameter calculation method that can provide highly reliable atmospheric data parameters for various flying wing aerodynamic layout aircraft, without being limited by the aerodynamic shape of the aircraft.

[0107] In one example of an embodiment of the present invention, the following are calculated according to the above method: the true Mach number error is no greater than 0.0065, the angle of attack α error is no greater than 0.6°, the sideslip angle error is no greater than 0.6°, the total pressure error is no greater than 35Pa, and the static pressure error is no greater than 10Pa.

[0108] It should be noted that if higher precision atmospheric data is required, compensation can be made based on the static pressure and total pressure corrections corresponding to each angle of attack, sideslip angle, and true Mach number.

[0109] In this embodiment, Tables 1 to 16 mentioned above are as follows:

[0110] Table 1: Local Mach Numbers when the True Mach Number Mt = 0.1

[0111]

[0112] Table 2: Local Mach Numbers when the True Mach Number Mt = 0.3

[0113]

[0114] Table 3: Local Mach Numbers when the True Mach Number Mt = 0.5

[0115]

[0116] Table 4: Local Mach Numbers when the True Mach Number Mt = 0.7

[0117]

[0118] Table 5: Angle-of-attack pressure coefficient at true Mach number Mt=0.1

[0119]

[0120] Table 6: Angle-of-attack pressure coefficient at true Mach number Mt=0.3

[0121]

[0122] Table 7: Angle-of-attack pressure coefficient at true Mach number Mt=0.5

[0123]

[0124] Table 8: Angle-of-attack pressure coefficient at true Mach number Mt=0.7

[0125]

[0126] Table 9: Sideslip angle pressure coefficient at true Mach number Mt=0.1

[0127]

[0128] Table 10: Sideslip angle pressure coefficient at true Mach number Mt=0.3

[0129]

[0130] Table 11: Sideslip angle pressure coefficient at true Mach number Mt=0.5

[0131]

[0132] Table 12: Sideslip angle pressure coefficient at true Mach number Mt=0.7

[0133]

[0134] Table 13: Static pressure coefficient at true Mach number Mt = 0.7

[0135]

[0136] Table 14: Static pressure coefficient at true Mach number Mt = 0.7

[0137]

[0138] Table 15: Static pressure coefficient at true Mach number Mt = 0.7

[0139]

[0140] Table 16: Static pressure coefficient at true Mach number Mt = 0.7

[0141]

[0142] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

[0143] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A method for calculating flight atmospheric parameters based on state uniqueness, characterized in that, The calculation of flight atmospheric parameters for flying wing aerodynamic configuration aircraft includes the following steps: S1. Through CFD simulation, construct numerical tables of local Mach number, angle-of-attack pressure coefficient, sideslip pressure coefficient, and hydrostatic pressure coefficient within the preset angle of attack and sideslip angle range for different real Mach numbers. S2. The pressure values ​​under various flight attitudes are collected by five embedded atmospheric data sensors that are conformally mounted to the surface of the flying wing aerodynamic layout aircraft, and the local Mach number is calculated. S3. Based on the local Mach number, obtain all the true Mach numbers, angle of attack and sideslip angle combination states by looking up the table, as well as the angle of attack pressure coefficient, sideslip angle pressure coefficient and static pressure coefficient corresponding to each combination state; S4. Based on the angle-of-attack pressure coefficient and sideslip angle pressure coefficient under each combination state, calculate the corresponding total pressure and static pressure, and obtain several candidate atmospheric parameter combinations by combining them with the actual Mach number. S5. Determine whether the total pressure, static pressure and true Mach number in each combination of atmospheric parameters are all valid. If so, the effective atmospheric parameter combination is output, including angle of attack, sideslip angle, total pressure, static pressure and true Mach number, to obtain a unique atmospheric parameter solution for the flight state; If not, return to step S2.

2. The method for calculating flight atmospheric parameters based on state uniqueness according to claim 1, characterized in that, In step S2, the installation method of the five embedded atmospheric data sensors is as follows: Three embedded atmospheric data sensors are installed on the upper fuselage surface of the flying wing aerodynamic layout aircraft, and the pressure values ​​they collect are P1, P2 and P4 respectively. The other two embedded atmospheric data sensors are installed on the lower fuselage surface of the flying wing aerodynamic layout aircraft, P3 and P5.

3. The method for calculating flight atmospheric parameters based on state uniqueness according to claim 1, characterized in that, In step S2, the method for calculating the local Mach number is as follows: S21. Determine whether the pressure values ​​collected by the five embedded atmospheric data sensors conformally mounted to the surface of the flying wing aerodynamic layout aircraft under each flight attitude are within the effective range. If so, proceed to step S22; If not, proceed to step S23; S22. Calculate the local Mach number based on the collected pressure values; S23. Continuously collect pressure values ​​under various flight attitudes and return to step S21; Wherein, the local Mach number The calculation formula is: In the formula, This represents the minimum of the five pressure values ​​collected, i.e., static pressure. This represents the maximum value among the five pressure values ​​collected, i.e., the total pressure.

4. The method for calculating flight atmospheric parameters based on state uniqueness according to claim 1, characterized in that, In step S4, the corresponding total pressure and static pressure are calculated by combining the calculation formulas for the angle of attack pressure coefficient and the sideslip angle pressure coefficient. Among them, the angle of attack pressure coefficient and the pressure coefficient of the sliding angle The calculation formulas are as follows: In the formula, P1, P2, and P4 represent the pressure values ​​collected by three embedded atmospheric data sensors installed on the upper fuselage surface of the flying wing aerodynamic layout aircraft, and P3 and P5 represent the pressure values ​​collected by two embedded atmospheric data sensors installed on the lower fuselage surface of the flying wing aerodynamic layout aircraft.

5. The method for calculating flight atmospheric parameters based on state uniqueness according to claim 1, characterized in that, In step S5, the method for determining whether the true Mach number in each candidate atmospheric parameter combination is valid is as follows: Determine whether the difference between the true Mach number and the threshold Mach number is within the allowable error range; If so, then the true Mach number is valid; If not, the true Mach number is invalid, and its corresponding candidate atmospheric parameter combination is eliminated.

6. The method for calculating flight atmospheric parameters based on state uniqueness according to claim 5, characterized in that, The method for determining the threshold Mach number is as follows: The total pressure and static pressure obtained by combining the formulas for calculating the pressure coefficient at the angle of attack and the pressure coefficient at the sideslip angle are substituted into the formula for calculating the local Mach number to obtain the threshold Mach number.

7. The method for calculating flight atmospheric parameters based on state uniqueness according to claim 5, characterized in that, In step S5, the method for determining whether static pressure and total pressure are valid among candidate atmospheric parameter combinations with effective true Mach numbers is as follows: Substitute the pressure values ​​collected by any two embedded atmospheric data sensors into the static pressure coefficient calculation formula to calculate the threshold static pressure and threshold total pressure at this time. Determine whether the differences between the threshold static pressure and the threshold total pressure and the static pressure and total pressure obtained by combining the formulas for calculating the pressure coefficient of the angle of attack and the pressure coefficient of the sideslip angle are all within the allowable error range; If so, then both the calculated static pressure and total pressure are valid; If not, the calculated static pressure and / or total pressure are invalid, and the corresponding candidate atmospheric parameter combinations are discarded.

8. The method for calculating flight atmospheric parameters based on state uniqueness according to claim 7, characterized in that, The formula for calculating the static pressure coefficient is as follows: In the formula, Indicates the threshold static pressure. Indicates the threshold full pressure. This represents the pressure values ​​collected by five embedded atmospheric data sensors.

Images