A dynamic CTS test method

Abstract

The present invention discloses a dynamic CTS test method, comprising: determining the conversion ratio between the test separation time and the actual separation time; calculating the model mass and the model virtual mass, the model moment of inertia, the model linear velocity, and the model angular velocity, and filling in the CTS test parameters; starting the wind tunnel test, converting the model linear velocity and the model angle at the initial test moment into the speed instruction of the six-degree-of-freedom mechanism drive component; the drive component moves according to the instruction; continuously collecting balance load data and wind tunnel aerodynamic parameter data, calculating the external attachment model linear velocity and the external attachment model angular velocity at the next test moment, and calculating the speed instruction of the six-degree-of-freedom mechanism drive component; repeating the above steps until the test requirements are met, saving the data, and stopping the test. This method has the advantages of accurate CTS test aerodynamic load measurement and convenient separation parameter setting, as well as the advantage of dynamic similarity to the launch test, providing a more effective test method for the study of multi-body separation problems.

Description

Technical Field

[0001] The present application relates to the technical field of multi-body separation wind tunnel testing, and in particular to a dynamic CTS testing method for dynamic simulation of multi-body separation problems. Background Art

[0002] During flight phases such as separation between spacecraft and rocket stages, and the launch and release of aircraft external stores, the separating bodies and the parent body are exposed to complex, interfering flow fields. Poor separation characteristics not only compromise performance but can also lead to collisions between the bodies and even endanger the safety of the parent body. Therefore, it is necessary to understand and analyze the separation characteristics of multi-body external store separations to provide a foundation for separation strategy design and safe separation research.

[0003] The CTS test is a ground-based test method for determining the aerodynamic and trajectory characteristics of external store separation in complex, interfering flow fields. It uses a combination of static force measurement and dynamic equation solution to gradually determine the aerodynamic loads and trajectory of the external store separation. Its advantages lie in the ability to accurately set the separation state parameters as needed, and the ability to accurately determine the static aerodynamic loads and trajectory. However, its disadvantage lies in the lack of dynamic aerodynamic load measurement, which is typically corrected by setting dynamic derivative parameters.

[0004] Another experimental technique used to study multi-body separation problems is the drop test. This involves ejecting a model to generate the initial separation velocity and initial separation angular velocity. The model then moves freely under wind tunnel conditions, and the separation trajectory is captured using high-speed photography. This technique has the advantage of simulating the dynamic separation process, taking into account the effects of dynamic aerodynamic loads. However, its disadvantages are that the initial separation velocity and initial separation angular velocity are difficult to accurately simulate and have poor repeatability. High-speed photography struggles to capture a comprehensive image of the model, making it difficult to obtain a six-degree-of-freedom trajectory. Furthermore, non-uniform flow conditions can lead to image distortion, which is difficult to resolve using image calibration.

[0005] The CTS test and the release test are complementary in terms of advantages and disadvantages. Therefore, it is necessary to explore a test method that combines the advantages of the CTS test and the release test. Summary of the Invention

[0006] The present application provides a dynamic CTS test method that can dynamically obtain the aerodynamic load and separation trajectory of the external attachment model, thereby making up for the deficiency of conventional CTS tests that do not consider dynamic aerodynamic loads and improving the test efficiency of multi-body separation CTS.

[0007] In a first aspect, a dynamic CTS test method is provided, comprising:

[0008] (1) The structure of the actual external store is reduced according to the scale ratio to obtain an external store model. Based on the dynamic similarity relationship, the CTS test parameters of the external store model, including the model linear velocity and model angular velocity, are determined;

[0009] (2) Move the external attachment model to a safe position away from the mother model through the six-degree-of-freedom mechanism, with the attitude of the external attachment model maintained at zero degrees. After the wind tunnel flow field stabilizes, move the external attachment model to the initial separation position;

[0010] (3) starting the wind tunnel test, recording the initial test time t(0), and calculating the speed command of the six-degree-of-freedom mechanism drive component based on the inverse relationship of the speed of the six-degree-of-freedom mechanism using the model linear velocity and model angular velocity calculated in step (1);

[0011] (4) The driving component moves according to the calculated driving component speed instruction, the wind tunnel carrier system continuously collects wind tunnel aerodynamic parameter data, and the wind tunnel balance continuously collects model aerodynamic load data and transmits them to the computer. The wind tunnel aerodynamic parameters and aerodynamic load data are substituted into the six-degree-of-freedom flight dynamics equation and kinematic equation to calculate the position, linear velocity, and angular velocity of the external store model at the next test time t(i);

[0012] (5) using the linear velocity and angular velocity of the external attachment model obtained in step (4), and calculating the speed command of the six-degree-of-freedom mechanism drive component according to the inverse velocity relationship of the six-degree-of-freedom mechanism;

[0013] (6) Repeat steps (4) to (5) until the test requirements are met, convert the aerodynamic load and posture data of the external attachment model into the aerodynamic load and posture data of the real external attachment, save the data, and stop the test.

[0014] In combination with the first aspect, in certain implementations of the first aspect, the model linear speed The model angular velocity where k q k is the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure, l is the size ratio between the external attachment model and the real external attachment, k m is the ratio of the model mass to the actual external attachment mass, V f is the linear velocity of the actual external attachment at the initial moment, ω f is the angular velocity of the actual external attachment at the initial moment.

[0015] In combination with the first aspect, in certain implementations of the first aspect, the CTS test parameters further include model mass, model virtual gravity, and model moment of inertia, wherein

[0016] Model mass m ex =k q*k l *k t 2 *m f

[0017] Model virtual gravity G V =(k q *k l 2 *m f -m ex )*g.

[0018] Model moment of inertia I ex =k m *k l 2 *I f

[0019] k q k is the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure, l is the size ratio between the external attachment model and the real external attachment, k t k is the conversion ratio between the experimental separation time and the actual separation time, m is the ratio of the model mass to the actual external attachment mass, m f is the actual mass of the external attachment, I f is the actual moment of inertia of the external attachment, k m is the ratio of the mass of the external attachment model to the mass of the actual external attachment, and g is the acceleration due to gravity.

[0020] In conjunction with the first aspect, in certain implementations of the first aspect, the conversion ratio k of the experimental separation time and the actual separation time is t Determined according to the wind tunnel parameter response time, where the wind tunnel parameter response time is the maximum value t1 among the flow field stabilization time, balance response time, and collector acquisition time. t1 is magnified n times as the test separation time t ex , according to the actual separation time t f , determine the conversion ratio k between the experimental separation time and the actual separation time t =t ex / t f .

[0021] In combination with the first aspect, in certain implementations of the first aspect, the safe position refers to a position where the external attachment model will not collide with the parent model due to shaking under a wind load.

[0022] In combination with the first aspect, in certain implementations of the first aspect, the six-degree-of-freedom mechanism is a 6-PTRT parallel mechanism, the six-degree-of-freedom mechanism driving component is a linear motion platform, and the speed of the six-degree-of-freedom mechanism driving component is the running speed of the slider on the linear motion platform.

[0023] In combination with the first aspect, in certain implementations of the first aspect, the method uses the velocity inverse relationship of the 6-PTRT parallel mechanism to convert the linear velocity and angular velocity of the external attachment model into the velocity of the six-degree-of-freedom mechanism driving component.

[0024] In conjunction with the first aspect, in certain implementations of the first aspect, converting the aerodynamic load and posture data of the external store model into the aerodynamic load and posture data of the real external store includes:

[0025] According to the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure, k q , the ratio of the external attachment model size to the actual external attachment size k l , the aerodynamic load of the external storage model [F ex , M ex ] is converted into the aerodynamic load of the real external storage [F f , M f ], F f =F ex / (k q k l 2 ), M f =M ex / (k q k l 3 ).

[0026] In conjunction with the first aspect, in certain implementations of the first aspect, converting the aerodynamic load and posture data of the external store model into the aerodynamic load and posture data of the real external store includes:

[0027] According to the ratio k of the external attachment model size to the actual external attachment size l , the displacement W of the external attachment model ex and Posture Z ex Converted to the displacement W of the real external attachment f =W ex / k l and Posture Z f =Z ex .

[0028] In conjunction with the first aspect, in certain implementations of the first aspect, converting the aerodynamic load and posture data of the external store model into the aerodynamic load and posture data of the real external store includes:

[0029] According to the conversion ratio k between the experimental separation time and the actual separation time t , the test separation time t ex Convert to real separation time

[0030] Compared with the existing technology, the solution provided by this application includes at least the following beneficial technical effects:

[0031] 1. Compared with the existing CTS test method, the dynamic CTS test method of the present invention uses dynamic force measurement to obtain the aerodynamic loads of the external store model in motion during the test, which overcomes the deficiency of the traditional CTS test method in not being able to directly measure the dynamic aerodynamic loads and improves the accuracy of multi-body separation simulation.

[0032] 2. Compared to the position control mode of conventional CTS tests in the prior art, the dynamic CTS test method of the present invention uses a velocity mode to control the movement of the external store model, shortening the test time and increasing the number of test trajectory points, thereby providing more research data for the multi-body separation problem;

[0033] 3. Compared with the launch test in the prior art, the dynamic CTS test method of the present invention can conveniently set the accurate initial separation linear velocity and initial separation angular velocity, directly obtain the separation aerodynamic load and separation posture trajectory during the separation process, and the repeatability is greatly improved compared with the launch test, which makes up for the shortcomings of the launch test and improves the test accuracy of the multi-body separation test. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the dynamic CTS test flow chart. DETAILED DESCRIPTION

[0035] The present application is described in further detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1 As shown, the present invention provides a dynamic CTS test method, which includes the following steps.

[0037] Step (1) is to reduce the structure of the real external attachment according to the size reduction ratio to obtain an external attachment model, and determine the CTS test parameters of the external attachment model according to the dynamic similarity relationship, including the model linear velocity and the model angular velocity.

[0038] Based on the relationship between the scale ratio of the external store model and the actual external store, the conversion ratio between the test separation time and the actual separation time, the actual external store mass, the actual external store moment of inertia, the actual external store linear velocity, the actual external store angular velocity and other parameters, the model mass and model virtual mass, model moment of inertia, model linear velocity, model angular velocity are calculated, and the CTS test parameters are filled in as follows:

[0039] Model mass m ex =k q *k l *k t 2*m f

[0040] Model virtual gravity G V =(k q *k l 2 *m f -m ex )*g.

[0041] Model moment of inertia I ex =k m *k l 2 *I f

[0042] Model linear speed

[0043] Model angular velocity

[0044] where k q k is the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure, l is the size ratio between the external attachment model and the real external attachment, k t is the conversion ratio between the experimental separation time and the actual separation time, m f is the actual mass of the external attachment, I f is the actual moment of inertia of the external attachment, k m is the ratio of the mass of the external attachment model to the mass of the real external attachment, V f is the linear velocity of the actual external attachment at the initial moment, ω f is the angular velocity of the actual external attachment at the initial moment, and g is the acceleration due to gravity.

[0045] In some embodiments, the conversion ratio k between the experimental separation time and the actual separation time is t It can be determined based on the wind tunnel parameter response time. For example, the wind tunnel parameter response time is the maximum value t1 among the flow field stabilization time, balance response time, and collector acquisition time. t1 is magnified n times as the test separation time t ex ,Right now:

[0046] t ex =t1*n

[0047] According to the real separation time t f , determine the conversion ratio k between the experimental separation time and the actual separation time t for:

[0048] k t =t ex / t f

[0049] Step (2) is to move the external attachment model to a safe position away from the mother model through the six-degree-of-freedom mechanism, with the posture of the external attachment model maintained at zero degrees. After the wind tunnel flow field stabilizes, the external attachment model is moved to the initial separation position.

[0050] The safe position refers to the position where the external attachment model will not collide with the mother model due to shaking under the wind load. In some embodiments, the safe position is that the external attachment model is below the aircraft model and the distance H from the lower surface of the aircraft model is S .

[0051] Step (3): Start the wind tunnel test, record the initial test time t(0), and convert the model linear velocity V calculated in step (1) into ex (0) and the model angular velocity ω ex (0), calculate the speed instructions of the six-degree-of-freedom mechanism driving components [S1(0), S2(0), S3(0), S4(0), S5(0), S6(0)] according to the inverse speed relationship of the six-degree-of-freedom mechanism.

[0052] In some embodiments, the six-degree-of-freedom mechanism is a 6-PTRT parallel mechanism, the six-degree-of-freedom mechanism driving component is a linear motion platform, and the speed of the six-degree-of-freedom mechanism driving component is the running speed of the slider on the linear motion platform.

[0053] Step (4): The driving component moves according to the calculated driving component speed instruction. The wind tunnel carrier system continuously collects wind tunnel aerodynamic parameter data. The wind tunnel balance continuously collects model aerodynamic load data and transmits them to the computer. The wind tunnel aerodynamic parameters and aerodynamic load data are substituted into the six-degree-of-freedom flight dynamics equation and kinematic equation to calculate the displacement W of the external attachment model at the next test time t(i). ex (i) and posture Z ex (i) Linear velocity V of the external attachment model ex (i) Angular velocity ω of the external attachment model ex (i).

[0054] Step (5): the linear velocity V of the external attachment model obtained in step (4) ex (i) and the angular velocity ω of the external attachment model ex (i) Calculate the speed instructions of the six-degree-of-freedom mechanism driving components [S1(i), S2(i), S3(i), S4(i), S5(i), S6(i)] according to the inverse speed relationship of the six-degree-of-freedom mechanism.

[0055] In some embodiments, the velocity inverse relationship of the 6-PTRT parallel mechanism is used to convert the linear velocity and angular velocity of the external attachment model into the velocity of the six-degree-of-freedom mechanism driving component.

[0056] Step (6): Repeat steps (4) to (5) until the test requirements are met, convert the aerodynamic load and posture data of the external attachment model into the aerodynamic load and posture data of the real external attachment, save the data, and stop the test.

[0057] In some embodiments, the test requirement is that the test time reaches t ex , according to the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure k q , the ratio of the external attachment model size to the actual external attachment size k l , the aerodynamic load of the external storage model [F ex , M ex ] is converted into the aerodynamic load of the real external storage [F f , M f ],in

[0058] F f =F ex / (k q k l 2 )

[0059] M f =M ex / (k q k l 3 )

[0060] According to the ratio k of the external attachment model size to the actual external attachment size l , the displacement W of the external attachment model ex and Posture Z ex Converted to the displacement W of the real external attachment f and Posture Z f ,in

[0061] W f =W ex / k l

[0062] Z f =Z ex

[0063] According to the conversion ratio k between the experimental separation time and the actual separation time y , the test separation time t ex Convert to real separation time t f ,in

[0064]

[0065] This method has the advantages of accurate aerodynamic load measurement and convenient separation parameter setting in CTS tests, as well as the advantage of dynamic similarity in launch tests, providing a more effective experimental means for the study of multi-body separation problems.

[0066] Although the present invention is disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims of the present invention.

Claims

1. A dynamic CTS test method, characterized in that: include: (1) The structure of the actual external store is reduced according to the scale ratio to obtain an external store model. Based on the dynamic similarity relationship, the CTS test parameters of the external store model, including the model linear velocity and model angular velocity, are determined; (2) Move the external attachment model to a safe position away from the mother model through the six-degree-of-freedom mechanism, with the attitude of the external attachment model maintained at zero degrees. After the wind tunnel flow field stabilizes, move the external attachment model to the initial separation position; (3) starting the wind tunnel test, recording the initial test time t(0), and calculating the speed command of the six-degree-of-freedom mechanism drive component based on the inverse relationship of the speed of the six-degree-of-freedom mechanism using the model linear velocity and model angular velocity calculated in step (1); (4) The driving component moves according to the calculated driving component speed instruction, the wind tunnel carrier system continuously collects wind tunnel aerodynamic parameter data, and the wind tunnel balance continuously collects model aerodynamic load data and transmits them to the computer. The wind tunnel aerodynamic parameters and aerodynamic load data are substituted into the six-degree-of-freedom flight dynamics equation and kinematic equation to calculate the position, linear velocity, and angular velocity of the external store model at the next test time t(i); (5) using the linear velocity and angular velocity of the external attachment model obtained in step (4) to calculate the speed command of the six-degree-of-freedom mechanism drive component according to the inverse velocity relationship of the six-degree-of-freedom mechanism; (6) Repeat steps (4) to (5) until the test requirements are met, convert the aerodynamic load and posture data of the external attachment model into the aerodynamic load and posture data of the real external attachment, save the data, and stop the test.

2. The method according to claim 1, characterized in that The model linear speed The model angular velocity where k q k is the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure, l is the size ratio between the external attachment model and the real external attachment, k m is the ratio of the model mass to the actual external attachment mass, V f is the linear velocity of the actual external attachment at the initial moment, ω f is the angular velocity of the actual external attachment at the initial moment.

3. The method according to claim 1, characterized in that CTS test parameters also include model mass, model virtual gravity, and model moment of inertia. Model mass m ex =k q *k l *k t 2 *m f Model virtual gravity G v =(k q *k l 2 *m f -m ex )*g Model moment of inertia I ex =k m *k l 2 *I f k q k is the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure, l is the size ratio between the external attachment model and the real external attachment, k t k is the conversion ratio between the experimental separation time and the actual separation time, m is the ratio of the model mass to the actual external attachment mass, m f is the actual mass of the external attachment, I f is the actual moment of inertia of the external attachment, k m is the ratio of the mass of the external attachment model to the mass of the actual external attachment, and g is the acceleration due to gravity.

4. The method according to claim 1, wherein The conversion ratio k between the experimental separation time and the actual separation time t Determined according to the wind tunnel parameter response time, where the wind tunnel parameter response time is the maximum value t1 among the flow field stabilization time, balance response time, and collector acquisition time. t1 is magnified n times as the test separation time t ex , according to the actual separation time t f , determine the conversion ratio k between the experimental separation time and the actual separation time t =t ex / t f .

5. The method according to claim 1, wherein The safe position refers to the position where the external attachment model will not collide with the parent model due to shaking under the wind load.

6. The method according to claim 1, characterized in that The six-degree-of-freedom mechanism is a 6-PTRT parallel mechanism, the driving component of the six-degree-of-freedom mechanism is a linear motion platform, and the speed of the driving component of the six-degree-of-freedom mechanism is the running speed of the slider on the linear motion platform.

7. The method according to claim 1, characterized in that The method adopts the velocity inverse relationship of the 6-PTRT parallel mechanism to convert the linear velocity and angular velocity of the external attachment model into the velocity of the six-degree-of-freedom mechanism driving component.

8. The method according to claim 1, characterized in that The step of converting the aerodynamic load and posture data of the external attachment model into aerodynamic load and posture data of a real external attachment includes: According to the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure, k q , the ratio of the external attachment model size to the actual external attachment size k l , the aerodynamic load of the external storage model [F ex , M ex ] is converted into the aerodynamic load of the real external storage [F f , M f ], F f =F ex / (k q k l 2 ), M f =M ex / (k q k l 3 ).

9. The method according to claim 1, characterized in that The step of converting the aerodynamic load and posture data of the external attachment model into aerodynamic load and posture data of a real external attachment includes: According to the ratio k of the external attachment model size to the actual external attachment size l , the displacement W of the external attachment model ex and Posture Z ex Converted to the displacement W of the real external attachment f =W ex / k l and Posture Z f =Z ex .

10. The method according to claim 1, characterized in that The step of converting the aerodynamic load and posture data of the external attachment model into aerodynamic load and posture data of a real external attachment includes: According to the conversion ratio k between the experimental separation time and the actual separation time t , the test separation time t ex Convert to real separation time

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