A high-precision correction method for elastic angle of balance applicable to engineering

Abstract

The present invention belongs to the technical field of wind tunnel tests, and discloses a high-precision correction method for the elastic angle of a balance applicable to engineering. The high-precision correction method for the elastic angle of a balance applicable to engineering of the present invention includes ground loading to obtain the elastic angle coefficient of a rod-type balance and a support system; real-time calculation of the elastic angle of an external hanger model; preliminary correction of the elastic angle of the external hanger model; and secondary correction of the elastic angle of the external hanger model. The high-precision correction method for the elastic angle of a balance applicable to engineering of the present invention can achieve a difference of 0.005° between the actual pitch attitude angle and the target pitch attitude angle, which fully meets the test accuracy requirements in engineering and has practical engineering value.

Description

Technical Field

[0001] The invention belongs to the technical field of wind tunnel tests, and in particular relates to a high-precision correction method for a balance elastic angle applicable to engineering. Background Art

[0002] When an external attachment of an aircraft is launched or dropped, the flight trajectory of the attachment will be disturbed due to the influence of the aircraft and other external attachments carried by the aircraft on the air flow field. In severe cases, it may cause a flight accident or even cause the aircraft to be destroyed and people to die. Therefore, in order to ensure the flight safety of the aircraft, it is necessary to select the appropriate launch or drop method and conditions, and the safety of the separation of the aircraft and the external attachment must be predicted before the actual test flight. At present, an important means of studying the safety of the separation of external attachments and aircraft is to conduct capture trajectory wind tunnel tests.

[0003] A wind tunnel is a pipe-shaped test device that produces uniform, controllable airflow within a test section. It is used to study air flow patterns and test the aerodynamic characteristics of aircraft or other objects. During a wind tunnel test, a scaled-down test model of the research object is supported in the wind tunnel test section, and the aerodynamic characteristics of the test model are studied using a test balance or other measurement methods. During the test, the test model is subjected to aerodynamic loads that are transmitted to the support system, causing elastic deformation and resulting in changes in the actual attitude angle of the test model. Currently, wind tunnel tests generally use the following methods: Figure 1 The actual attitude angle α of the test model shown is the nominal attitude angle α0 and the elastic angle The actual posture angle α of the test model is defined by the sum of .

[0004] The capture trajectory wind tunnel test technology uses the cooperation of computers, six-degree-of-freedom motion mechanisms and wind tunnels to measure the aerodynamic load of the external attachment model at each separation moment, and solve the motion equation to solve the position and attitude of the external attachment model at the next moment. After receiving the command, the external attachment model supported by the six-degree-of-freedom motion mechanism moves to the specified position and attitude to measure the aerodynamic force and torque of the external attachment model, and reciprocates to simulate the trajectory of external attachment release. During the test, the external attachment model is affected by the airflow to generate aerodynamic loads, causing elastic deformation of the model support system, and the actual attitude angle of the external attachment model deviates from the target value. If the elastic angle correction is not performed on the actual attitude angle of the model, it will be detrimental to the accuracy of the separation trajectory prediction.

[0005] The current processing method is: through ground loading, the elastic angle coefficient (the elastic angle generated by the unit aerodynamic force or torque) of the balance and support system is checked. During the test, the measurement system obtains the aerodynamic load of the external attachment at the target position and attitude, and the computer calculates the corresponding elastic angle in real time, and eliminates the attitude angle deviation of the model caused by the elastic angle through the six-degree-of-freedom motion mechanism. In actual experiments, the maximum value of the elastic angle of the external attachment is generally about 10% of the nominal attitude angle value. However, under the condition of large attitude angle of the external attachment (about 20°), the correction deviation of the model elastic angle is large, and the maximum can reach about 0.1°. Since the time interval between adjacent separation moments is small (generally 0.01s), the attitude angle change between adjacent separation moments is small (generally no more than 1°), that is, the elastic angle correction deviation is at the same order of magnitude as the attitude angle change value. Under such conditions where the attitude angle of the large-load external attachment model is large, the use of existing methods for elastic angle correction has a greater impact on the accuracy of the test data.

[0006] Currently, there is an urgent need to develop a high-precision correction method for the elastic angle of a balance that is applicable to engineering. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a high-precision correction method for elastic angle of a balance applicable to engineering, so as to overcome the defects of the prior art.

[0008] The high-precision correction method for elastic angle of a balance applicable to engineering of the present invention comprises the following steps:

[0009] S10. Ground loading to obtain the elastic angular coefficient of the beam balance and the support system;

[0010] Carry out ground loading in the laboratory to obtain the elastic angular coefficient of the beam balance and the support system. The elastic angular coefficient represents the influence of the beam balance and the support system on the attitude angle of the test model after being loaded. The elastic angular coefficient is the elastic angle generated by the unit aerodynamic force or moment, and the unit is ° / N or ° / N·m.

[0011] The support system includes a tail support rod and a support device, the front end of the tail support rod is fixedly connected to the rear end of the rod-type balance, and the rear end of the tail support rod is fixedly connected to the interface of the support device;

[0012] Overall elastic angle of support system :

[0013] ;

[0014] in, is the overall elastic angular coefficient, F is the aerodynamic force or torque;

[0015] Right now:

[0016] ;

[0017] in, is the elastic angle of attack, is the elastic sideslip angle, is the elastic rolling angle; For lift, is the pitching moment, Z is the lateral force, is the yaw moment, is the rolling moment; is the second-order elastic coefficient of lift angle of attack, is the second-order elastic coefficient of the pitch moment angle of attack, is the second-order elastic coefficient of the lateral force and sideslip angle, is the second-order elastic coefficient of the yaw moment and sideslip angle, is the second-order elastic coefficient of rolling moment and rolling angle;

[0018] S20. Calculate the elastic angle of the external attachment model in real time;

[0019] During the wind tunnel test, the external attachment model is moved to the target attitude angle (α0, β0, γ0) according to the instructions with the help of a six-degree-of-freedom motion mechanism. The aerodynamic force and moment of the external attachment model are measured by a rod balance, and the elastic angle (Δα1, Δβ1, Δγ1) of the external attachment model is calculated in real time according to the overall elastic angle calculation formula of the support system.

[0020] S20 does not correct the elastic angle of the external attachment, and the attitude angle deviation of the external attachment model is obtained as (Δα1, Δβ1, Δγ1); wherein α0 is the target angle of attack, β0 is the target sideslip angle, and γ0 is the target roll angle; Δα1 is the elastic angle without correction of the angle of attack, Δβ1 is the elastic angle without correction of the sideslip angle, and Δγ1 is the elastic angle without correction of the roll angle;

[0021] S30. Preliminary correction of the elastic angle of the external attachment model;

[0022] With the help of a six-degree-of-freedom motion mechanism, after the external attachment model is moved to the attitude angle (α0-Δα1, β0-Δβ1, γ0-Δγ1) according to the command, the aerodynamic force and torque of the external attachment model are measured by a rod balance, and the elastic angle (Δα2, Δβ2, Δγ2) corresponding to the external attachment model under the attitude angle (α0-Δα1, β0-Δβ1, γ0-Δγ1) is calculated in real time according to the overall elastic angle calculation formula of the support system;

[0023] S30 performs preliminary correction on the elastic angle of the external attachment model, and obtains the attitude angle deviation of the external attachment model as (Δα1-Δα2, Δβ1-Δβ2, Δγ1-Δγ2); wherein Δα2 is the preliminary correction elastic angle of the attack angle, Δβ2 is the preliminary correction elastic angle of the sideslip angle, and Δγ2 is the preliminary correction elastic angle of the roll angle;

[0024] S40. Secondary correction of the elastic angle of the external attachment model;

[0025] With the help of the six-degree-of-freedom motion mechanism, after the external attachment model continues to run according to the instructions (Δα1-Δα2, Δβ1-Δβ2, Δγ1-Δγ2), the aerodynamic force and torque of the external attachment model are measured by a rod balance, and the elastic angle (Δα3, Δβ3, Δγ3) of the external attachment model is solved in real time according to the calculation formula of the overall elastic angle of the support system;

[0026] S40 performs secondary correction on the elastic angle of the external attachment model, and the actual attitude angle of the external attachment model, that is, the final corrected attitude angle, is obtained as (α0-Δα2+Δα3, β0-Δβ2+Δβ3, γ0-Δγ2+Δγ3); the difference between the final corrected attitude angle and the target attitude angle (α0, β0, γ0) is (Δα2-Δα3, Δβ2-Δβ3, Δγ2-Δγ3).

[0027] Furthermore, the magnitude estimation method of the difference between the final corrected attitude angle and the target attitude angle is as follows:

[0028] Within the range of the beam balance, the elastic angle of the test model changes linearly with the load; the elastic angle of the test model is a linear function of the attitude angle;

[0029] For angle of attack:

[0030] ;

[0031] Among them, α is the model nominal angle of attack, Δα is the corresponding model elastic angle, k and b are constant coefficients;

[0032] From this we can get:

[0033] ;

[0034] Then the magnitude of the difference between the final corrected attitude angle and the target attitude angle is estimated as:

[0035] ;

[0036] It can be seen that when k = 0.1, the difference is 0.1% of the target attitude angle.

[0037] The high-precision correction method for balance elastic angle applicable to engineering of the present invention can achieve a difference of 0.005° between the actual pitch attitude angle and the target pitch attitude angle, fully meets the test accuracy requirements in engineering, and has practical engineering value. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the actual attitude angle, nominal attitude angle and elastic angle of the test model;

[0039] Figure 2 A flow chart of a high-precision correction method for elastic angle of a balance applicable to the engineering of the present invention;

[0040] Figure 3 is the difference between the actual pitch attitude angle and the target pitch attitude angle (uncorrected elastic angle);

[0041] Figure 4 is the difference between the actual pitch attitude angle and the target pitch attitude angle (preliminary correction elastic angle);

[0042] Figure 5 It is the difference between the actual pitch attitude angle and the target pitch attitude angle (secondary corrected elastic angle). DETAILED DESCRIPTION

[0043] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0044] Embodiment: The test wind tunnel of this embodiment is a 1.2-meter temporary wind tunnel, the cross section of the wind tunnel test section is 1.2m×1.2m, and the Ma number range is 0.4-3.0. The length of the subsonic test section is 3.6m, and the side walls on both sides are straight hole walls with optical glass observation windows. A six-component rod strain balance with a diameter of 8mm is used to measure the aerodynamic load, and the test Ma number is 0.8. This embodiment corrects the angle of attack of the external attachment model.

[0045] like Figure 2 As shown, the high-precision correction method for the elastic angle of a balance applicable to the project of this embodiment includes the following steps:

[0046] S10. Ground loading to obtain the elastic angular coefficient of the beam balance and the support system;

[0047] Carry out ground loading in the laboratory and obtain the elastic angular coefficient of the beam balance and the support system: .

[0048] S20. Calculate the elastic angle of the external attachment model in real time;

[0049] During the wind tunnel test, with the help of a six-degree-of-freedom motion mechanism, the external attachment model is moved to the target attitude angle α0 according to the command, and the aerodynamic force and moment of the external attachment model are measured by a rod balance, and the elastic angle Δα1 of the external attachment model is calculated in real time according to the overall elastic angle calculation formula of the support system;

[0050] S30. Preliminary correction of the elastic angle of the external attachment model;

[0051] With the help of the six-degree-of-freedom motion mechanism, the external attachment model is moved to the attitude angle α0-Δα1 according to the instruction, and the aerodynamic force and torque of the external attachment model are measured by a rod balance. The elastic angle Δα2 of the external attachment model is calculated in real time according to the overall elastic angle calculation formula of the support system, and the elastic angle of the external attachment model is preliminarily corrected. The attitude angle deviation of the external attachment model is obtained as Δα1-Δα2;

[0052] S40. Secondary correction of the elastic angle of the external attachment model;

[0053] With the help of the six-degree-of-freedom motion mechanism, the external attachment model continues to run Δα1-Δα2 according to the instructions, and then the aerodynamic force and torque of the external attachment model are measured by a rod balance, and the elastic angle Δα3 of the external attachment model is calculated in real time according to the overall elastic angle calculation formula of the support system. The actual attitude angle of the external attachment model obtained, that is, the final corrected attitude angle, is α0-Δα2+Δα3; the difference between the final corrected attitude angle and the target attitude angle α0 is Δα2-Δα3.

[0054] Depend on Figure 3 to Figure 5 It can be seen that after the secondary correction of the elastic angle of attack of the external attachment model, the difference between the actual pitch attitude angle and the target pitch attitude angle has been reduced to about 0.005°, which fully meets the test accuracy requirements in engineering.

[0055] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and implementation modes. For those familiar with the art, all features disclosed in the present invention, or steps in all methods or processes disclosed, 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 high-precision correction method for elastic angle of a balance applicable to engineering, characterized in that: The following steps are involved: S10. Ground loading to obtain the elastic angular coefficient of the beam balance and the support system; Carry out ground loading in the laboratory to obtain the elastic angular coefficient of the beam balance and the support system. The elastic angular coefficient represents the influence of the beam balance and the support system on the attitude angle of the test model after being loaded. The elastic angular coefficient is the elastic angle generated by the unit aerodynamic force or moment, and the unit is ° / N or ° / N·m. The support system includes a tail support rod and a support device, the front end of the tail support rod is fixedly connected to the rear end of the rod-type balance, and the rear end of the tail support rod is fixedly connected to the interface of the support device; Overall elastic angle of support system : ； in, is the overall elastic angular coefficient, F is the aerodynamic force or torque; Right now: ； in, is the elastic angle of attack, is the elastic sideslip angle, is the elastic rolling angle; For lift, is the pitching moment, Z is the lateral force, is the yaw moment, is the rolling moment; is the second-order elastic coefficient of lift angle of attack, is the second-order elastic coefficient of the pitch moment angle of attack, is the second-order elastic coefficient of the lateral force and sideslip angle, is the second-order elastic coefficient of the yaw moment and sideslip angle, is the second-order elastic coefficient of rolling moment and rolling angle; S20. Calculate the elastic angle of the external attachment model in real time; During the wind tunnel test, the external attachment model is moved to the target attitude angle (α0, β0, γ0) according to the instructions with the help of a six-degree-of-freedom motion mechanism. The aerodynamic force and moment of the external attachment model are measured by a rod balance, and the elastic angle (Δα1, Δβ1, Δγ1) of the external attachment model is calculated in real time according to the overall elastic angle calculation formula of the support system. S20 does not correct the elastic angle of the external attachment, and the attitude angle deviation of the external attachment model is obtained as (Δα1, Δβ1, Δγ1); wherein α0 is the target angle of attack, β0 is the target sideslip angle, and γ0 is the target roll angle; Δα1 is the elastic angle without correction of the angle of attack, Δβ1 is the elastic angle without correction of the sideslip angle, and Δγ1 is the elastic angle without correction of the roll angle; S30. Preliminary correction of the elastic angle of the external attachment model; With the help of a six-degree-of-freedom motion mechanism, after the external attachment model is moved to the attitude angle (α0-Δα1, β0-Δβ1, γ0-Δγ1) according to the command, the aerodynamic force and torque of the external attachment model are measured by a rod balance, and the elastic angle (Δα2, Δβ2, Δγ2) corresponding to the external attachment model under the attitude angle (α0-Δα1, β0-Δβ1, γ0-Δγ1) is calculated in real time according to the overall elastic angle calculation formula of the support system; S30 performs preliminary correction on the elastic angle of the external attachment model, and obtains the attitude angle deviation of the external attachment model as (Δα1-Δα2, Δβ1-Δβ2, Δγ1-Δγ2); wherein Δα2 is the preliminary correction elastic angle of the attack angle, Δβ2 is the preliminary correction elastic angle of the sideslip angle, and Δγ2 is the preliminary correction elastic angle of the roll angle; S40. Secondary correction of the elastic angle of the external attachment model; With the help of the six-degree-of-freedom motion mechanism, after the external attachment model continues to run according to the instructions (Δα1-Δα2, Δβ1-Δβ2, Δγ1-Δγ2), the aerodynamic force and torque of the external attachment model are measured by a rod balance, and the elastic angle (Δα3, Δβ3, Δγ3) of the external attachment model is solved in real time according to the calculation formula of the overall elastic angle of the support system; S40 performs secondary correction on the elastic angle of the external attachment model, and the actual attitude angle of the external attachment model, that is, the final corrected attitude angle, is obtained as (α0-Δα2+Δα3, β0-Δβ2+Δβ3, γ0-Δγ2+Δγ3); the difference between the final corrected attitude angle and the target attitude angle (α0, β0, γ0) is (Δα2-Δα3, Δβ2-Δβ3, Δγ2-Δγ3).

2. A high-precision correction method for elastic angle of a balance applicable to engineering according to claim 1, characterized in that: The magnitude estimation method of the difference between the final corrected attitude angle and the target attitude angle is as follows: Within the range of the beam balance, the elastic angle of the test model changes linearly with the load; the elastic angle of the test model is a linear function of the attitude angle; For angle of attack: ； Among them, α is the model nominal attack angle, Δα is the corresponding model elastic angle, k and b are constant coefficients; From this we can get: ； Then the magnitude of the difference between the final corrected attitude angle and the target attitude angle is estimated as: ； It can be seen that when k = 0.1, the difference is 0.1% of the target attitude angle.

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