A method for processing continuous wind tunnel balance calibration data

Abstract

The present invention belongs to the technical field of multi-component aerodynamic load measurement sensors and discloses a method for processing calibration data for a continuous wind tunnel balance, comprising configuring calibration parameters; performing ground calibration of the continuous wind tunnel balance; performing ground calibration data processing; screening a set of working matrices, and selecting a continuous wind tunnel balance working matrix and an alternative matrix. Based on the multi-bridge characteristics of the continuous wind tunnel balance and an existing ground calibration system for the balance, the method recombines the multiple bridges to form multiple calibration data combinations, performs data processing according to a unit calibration method or a multivariate calibration method, obtains a set of working matrices, calculates the error values ​​of each working matrix based on the test load, screens the working matrix with the smallest error value as the continuous wind tunnel balance working matrix, and determines an alternative matrix. The method for processing calibration data for a continuous wind tunnel balance of the present invention realizes continuous wind tunnel balance calibration, achieves good technical results, and has practical engineering value.

Description

Technical Field

[0001] The invention belongs to the technical field of multi-component aerodynamic load measurement sensors, and in particular relates to a continuous wind tunnel balance calibration data processing method. Background Art

[0002] A wind tunnel balance is a multi-dimensional force sensor. It measures the following aerodynamic components: drag (X), lift (Y), and side force (Z); and the following moment components: roll moment (Mx), yaw moment (My), and pitch moment (Mz). Generally, the six components of a wind tunnel balance correspond to six Wheatstone bridges, one for each force and moment. Each Wheatstone bridge is constructed using four identical strain gauges connected in series and then in parallel, and is excited by a constant voltage. During wind tunnel testing, the Wheatstone bridge senses the load, causing a slight deformation. This slight deformation changes the resistance of the strain gauges in the Wheatstone bridge, resulting in a voltage change (ΔU). The aerodynamic load acting on the balance can be calculated from the balance's working matrix, obtained through ground calibration.

[0003] Ground calibration of a balance, also known as static calibration, simulates the force applied to the balance during a wind tunnel test using a defined coordinate system. Static loads are then applied to the balance, and the output voltage signals of each balance component and the working matrix of the calibration loads are calculated for use in calculating aerodynamic loads during wind tunnel testing. Calibration methods can be categorized as unit calibration or multivariate calibration based on the loading method. Unit calibration involves independently loading each balance component, while other components are held at zero or constant values. The corresponding data processing method is generally the least squares method. Multivariate calibration involves simultaneously loading each balance component according to a specific pattern, forming a combination of values. The corresponding data processing method is generally a multivariate linear regression algorithm.

[0004] Compared to transient wind tunnels, continuous wind tunnels offer advantages such as stable airflow, extended operating times, a wide range of test conditions, and high test efficiency. However, whereas transient wind tunnels typically operate for approximately one minute at a time, continuous wind tunnels require hours of operation once started, placing higher demands on their core measuring equipment: the wind tunnel balance. During extended operation, if a bridge in the wind tunnel balance fails, operation must be halted, resulting in losses exceeding RMB 100,000. Therefore, continuous wind tunnels require the development of a backup bridge for the wind tunnel balance.

[0005] Therefore, to meet the high demands of continuous wind tunnel balance measurements, a continuous wind tunnel balance must be designed and manufactured. The balance incorporates redundancy across its six components, with each component equipped with two Wheatstone bridges: one primary and one backup. If a Wheatstone bridge fails during a continuous wind tunnel test, the backup bridge can continue measurements, ensuring the high robustness of the balance.

[0006] Currently, there is an urgent need to develop a continuous wind tunnel balance calibration data processing method. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a continuous wind tunnel balance calibration data processing method to overcome the defects of the prior art.

[0008] The continuous wind tunnel balance calibration data processing method of the present invention comprises the following steps:

[0009] S10. Configure calibration parameters;

[0010] S20. Perform ground calibration;

[0011] S30. Perform ground calibration data processing;

[0012] S40. Screen the working matrix set and select the continuous wind tunnel balance working matrix and alternative matrix.

[0013] Furthermore, the configuration calibration parameters of S10 include the following steps:

[0014] S11. Fill in the calibration load based on the design load of the continuous wind tunnel balance. Each calibration load should be 90% to 110% of the design range of the corresponding component.

[0015] S12. Perform calibration of the balance ground calibration system, including the moment arm, loading ladder, and loading device;

[0016] S13. Set the bridge information of the wind tunnel balance, compile the load group, determine the unit terms, cross terms and multivariate terms, and determine the corresponding test loads.

[0017] Furthermore, the ground calibration in S20 includes the following steps:

[0018] S21. Load, reset, and collect and record the corresponding original calibration data according to the load group;

[0019] S22. Use unit calibration to load unit terms and cross terms; use multivariate calibration to load multivariate terms;

[0020] S23. Apply the test load.

[0021] Furthermore, the ground calibration data processing in S30 includes the following steps:

[0022] S31. Combine the six components in the order of drag force X, lift force Y, lateral force Z, rolling moment Mx, yaw moment My, and pitching moment Mz. For drag force X, the corresponding measurement bridges are M11 and M12. The three options M11, M12, and M11+M12 are used as calibration data for drag force X for ground calibration data processing. Similarly, lift force Y, lateral force Z, rolling moment Mx, yaw moment My, and pitching moment Mz each have three corresponding options. The six components of the continuous wind tunnel balance have a total of 3×3×3×3×3×3=3 6 =729 combinations;

[0023] S32. The unit calibration method uses the least squares method for data processing, and the multivariate calibration method uses the multivariate linear regression algorithm for data processing. The working matrix set of the continuous wind tunnel balance is fitted, and the working matrix set includes 729 working matrices.

[0024] S33. Substitute the test load into each of the 729 working matrices in the working matrix set to obtain 729 corresponding error values. Each error value is characterized by a standard deviation.

[0025] Furthermore, the screening matrix set of S40 includes the following steps:

[0026] S41. Filter out the working matrix with the smallest error value and use it as the working matrix for the continuous wind tunnel balance;

[0027] S42. Select an alternative matrix;

[0028] The Wheatstone bridges corresponding to the working matrices with the smallest error values ​​for drag X, lift Y, side force Z, rolling moment Mx, yaw moment My, and pitching moment Mz are named M1 to M6 respectively. If a Wheatstone bridge of a component in M1 to M6 is damaged, the corresponding backup bridge is activated. The working matrix of the backup bridge is 3 of the remaining 5 components other than the damaged component. 5 =The working matrix with the smallest error value among the 243 working matrices is used to calculate the aerodynamic load of the damaged component through the spare bridge path.

[0029] The continuous wind tunnel balance calibration data processing method of the present invention is based on the multi-bridge characteristics of the continuous wind tunnel balance and the existing balance ground calibration system. The multi-bridge paths are recombined to form multiple calibration data combinations. The data is processed according to the unit calibration method or the multivariate calibration method to obtain a working matrix set. The error value of each working matrix is ​​then calculated based on the test load. The working matrix with the smallest error value is screened out as the working matrix of the continuous wind tunnel balance, and an alternative matrix is ​​determined.

[0030] The present invention's continuous wind tunnel balance calibration data processing method improves the quality of wind tunnel test data. Based on the existing balance ground calibration system hardware, no additional supporting facilities or calibration steps are required. Based on the existing balance ground calibration system software, the method selects the working matrix with the smallest error value from 729 working matrices of six components as the continuous wind tunnel balance working matrix. The working matrix with the smallest error value from the remaining 243 working matrices of five components is then selected as the backup bridge circuit, thereby improving balance calibration accuracy and wind tunnel test data quality.

[0031] The present invention improves the efficiency of wind tunnel testing by processing calibration data for continuous wind tunnel balances. Continuous wind tunnels, particularly large ones, have long test preparation cycles. If a test is interrupted by a failure, such as damage to the balance bridge, then resuming the test can take at least several dozen hours. By employing the present invention, even if one or more Wheatstone bridges in the continuous wind tunnel balance fail, the calculation matrix of the combination of normal bridges can be selected without interrupting the test. This improves the efficiency of continuous wind tunnel testing and has practical engineering value. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1a The Wheatstone bridge attachment position diagram for the Y and Mz elements of the continuous wind tunnel balance (top view);

[0033] Figure 1b The Wheatstone bridge attachment position diagram for the X, Z, Mx, and My elements of the continuous wind tunnel balance (main view);

[0034] Figure 2a Schematic diagram of the attachment position of the Wheatstone full-bridge strain gauge (partial view of the main view);

[0035] Figure 2b This is the Wheatstone full bridge measurement schematic;

[0036] Figure 3a Schematic diagram of the Wheatstone bridge attachment position of the continuous wind tunnel balance (main view);

[0037] Figure 3b Schematic diagram of the Wheatstone bridge attachment position for the continuous wind tunnel balance (top view);

[0038] Figure 3c Schematic diagram of the strain gauge connection of the Wheatstone full bridge of the continuous wind tunnel balance;

[0039] Figure 4a Schematic diagram of the reconfiguration of the Wheatstone full bridge for the continuous wind tunnel balance (full image);

[0040] Figure 4bSchematic diagram of the reconfiguration of the Wheatstone full bridge for the continuous wind tunnel balance (Part I);

[0041] Figure 4c Schematic diagram of the reconfiguration of the Wheatstone full bridge for the continuous wind tunnel balance (Part II);

[0042] Figure 5 Flow chart for ground calibration of a continuous wind tunnel balance.

[0043] In the figure, 1 to 48 are the strain gauge numbers. DETAILED DESCRIPTION

[0044] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0045] Example: The Wheatstone bridge attachment position and the corresponding balance coordinate system of the continuous wind tunnel balance of this embodiment are shown in Figure 1a 、 Figure 1b See you at the Wheatstone Bridge Figure 2a 、 Figure 2b The Wheatstone full bridge uses four identical strain gauges connected in series and then in parallel. R1, R2, R3, and R4 are the resistance values ​​of the bridge arms, U is the excitation voltage for the bridge, and △U is the output voltage. See the attachment position of the Wheatstone full bridge of the continuous wind tunnel balance for details. Figure 3a 、 Figure 3b , the corresponding strain gauge connection diagram is shown in Figure 3c .

[0046] like Figure 5 As shown, the continuous wind tunnel balance calibration data processing method of this embodiment includes the following steps:

[0047] S10. Configure calibration parameters;

[0048] S20. Perform ground calibration;

[0049] S30. Perform ground calibration data processing;

[0050] S40. Screen the working matrix set and select the continuous wind tunnel balance working matrix and alternative matrix.

[0051] Furthermore, the configuration calibration parameters of S10 include the following steps:

[0052] S11. Fill in the calibration load based on the design load of the continuous wind tunnel balance. Each calibration load should be 90% to 110% of the design range of the corresponding component.

[0053] S12. Perform calibration of the balance ground calibration system, including the moment arm, loading ladder, and loading device;

[0054] S13. Set the bridge information of the wind tunnel balance, compile the load group, determine the unit terms, cross terms and multivariate terms, and determine the corresponding test loads.

[0055] Furthermore, the ground calibration in S20 includes the following steps:

[0056] S21. Load, reset, and collect and record the corresponding original calibration data according to the load group;

[0057] S22. Use unit calibration to load unit terms and cross terms; use multivariate calibration to load multivariate terms;

[0058] S23. Apply the test load.

[0059] Furthermore, the ground calibration data processing in S30 includes the following steps:

[0060] S31. Combine the six components in the order of drag force X, lift force Y, lateral force Z, rolling moment Mx, yaw moment My, and pitching moment Mz. For drag force X, the corresponding measurement bridges are M11 and M12. The three options M11, M12, and M11+M12 are used as calibration data for drag force X for ground calibration data processing. Similarly, lift force Y, lateral force Z, rolling moment Mx, yaw moment My, and pitching moment Mz each have three corresponding options. The six components of the continuous wind tunnel balance have a total of 3×3×3×3×3×3=3 6 =729 combinations; see combination method Figure 4a to Figure 4c ;

[0061] S32. The unit calibration method uses the least squares method for data processing, and the multivariate calibration method uses the multivariate linear regression algorithm for data processing. The working matrix set of the continuous wind tunnel balance is fitted. The working matrix set includes 729 working matrices; some of the working matrices are shown in Table 1.

[0062] S33. Substitute the test load into each of the 729 working matrices in the working matrix set to obtain 729 corresponding error values. Each error value is characterized by a standard deviation.

[0063] Furthermore, the screening matrix set of S40 includes the following steps:

[0064] S41. Filter out the working matrix with the smallest error value and use it as the working matrix for the continuous wind tunnel balance;

[0065] S42. Select an alternative matrix;

[0066] The Wheatstone bridges corresponding to the working matrices with the smallest error values ​​for drag X, lift Y, side force Z, rolling moment Mx, yaw moment My, and pitching moment Mz are named M1 to M6 respectively. If a Wheatstone bridge of a component in M1 to M6 is damaged, the corresponding backup bridge is activated. The working matrix of the backup bridge is 3 of the remaining 5 components other than the damaged component. 5 = The working matrix with the smallest error value among the 243 working matrices is used to calculate the aerodynamic load of the damaged component through the backup bridge. The working matrix of the backup bridge is shown in Table 2.

[0067] Table 1 Working matrix of continuous wind tunnel balance (partial)

[0068]

[0069] Table 2 Backup bridge circuits of the working matrix

[0070]

[0071] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the description and implementation methods. For those familiar with the art, all features disclosed in the present invention, or all steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way without departing from the principles of the present invention. The present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for processing continuous wind tunnel balance calibration data, characterized in that: The following steps are involved: S10. Configure calibration parameters; S20. Perform ground calibration; comprising the following steps: S21. Load, reset, and collect and record the corresponding original calibration data according to the load group; S22. Use unit calibration to load unit terms and cross terms; use multivariate calibration to load multivariate terms; S23. Loading test load; S30. Perform ground calibration data processing; comprising the following steps: S31. Combine the six components in the order of drag force X, lift force Y, lateral force Z, rolling moment Mx, yaw moment My, and pitching moment Mz. For drag force X, the corresponding measurement bridges are M11 and M12. The three options M11, M12, and M11+M12 are used as calibration data for drag force X for ground calibration data processing. Similarly, lift force Y, lateral force Z, rolling moment Mx, yaw moment My, and pitching moment Mz each have three corresponding options. The six components of the continuous wind tunnel balance have a total of 3×3×3×3×3×3=3 6 =729 combinations; S32. The unit calibration method uses the least squares method for data processing, and the multivariate calibration method uses the multivariate linear regression algorithm for data processing. The working matrix set of the continuous wind tunnel balance is fitted, and the working matrix set includes 729 working matrices. S33. Substitute the test load into each of the 729 working matrices in the working matrix set to obtain 729 corresponding error values, each of which is characterized by a standard deviation. S40. Screening the working matrix set and selecting the continuous wind tunnel balance working matrix and the candidate matrix; comprising the following steps: S41. Filter out the working matrix with the smallest error value and use it as the working matrix for the continuous wind tunnel balance; S42. Select an alternative matrix; The Wheatstone bridges corresponding to the working matrices with the smallest error values ​​for drag X, lift Y, side force Z, rolling moment Mx, yaw moment My, and pitching moment Mz are named M1 to M6 respectively. If a Wheatstone bridge of a component in M1 to M6 is damaged, the corresponding backup bridge is activated. The working matrix of the backup bridge is 3 of the remaining 5 components other than the damaged component. 5 =The working matrix with the smallest error value among the 243 working matrices is used to calculate the aerodynamic load of the damaged component through the spare bridge path.

2. The method for processing continuous wind tunnel balance calibration data according to claim 1, characterized in that: The configuration and calibration parameters of the S10 include the following steps: S11. Fill in the calibration load based on the design load of the continuous wind tunnel balance. Each calibration load should be 90% to 110% of the design range of the corresponding component. S12. Perform calibration of the balance ground calibration system, including the moment arm, loading ladder, and loading device; S13. Set the bridge information of the wind tunnel balance, compile the load group, determine the unit terms, cross terms and multivariate terms, and determine the corresponding test loads.

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