Dynamic CTS test method

Abstract

The invention discloses a dynamic CTS test method. The method comprises the following steps: determining a conversion ratio of test separation time to real separation time; the model mass, the model virtual mass, the model rotational inertia, the model linear velocity and the model angular velocity are calculated, and CTS test parameters are filled in; starting a wind tunnel test, and converting the model linear velocity and the model angle at the initial test moment into a six-degree-of-freedom mechanism driving part speed instruction; the driving part moves according to the instruction; continuously collecting balance load data and wind tunnel pneumatic parameter data, calculating the linear velocity and angular velocity of the external store model at the next test moment, and calculating a speed instruction of a driving part of the six-degree-of-freedom mechanism; and repeating the steps until the test requirements are met, storing the data, and stopping the test. The method not only has the advantages of accurate measurement of the aerodynamic load in the CTS test and convenient setting of the separation parameters, but also has the advantage similar to the dynamics of the throwing test, and provides a more effective test means for the research of the multi-body separation problem.

Description

Technical Field

[0001] This application relates to the technical field of multibody separation wind tunnel testing, and in particular to a dynamic CTS testing method for dynamic simulation of multibody separation problems. Background Technology

[0002] During the flight phases of spacecraft and rockets, including stage separation and the launch and release of external stores from aircraft, the separated components and the parent component are situated in complex, mutually interfering flow fields. Poor separation characteristics not only affect performance but can also lead to collisions between multiple components, and even endanger the safety of the parent component. Therefore, it is necessary to acquire and analyze the separation characteristics of multi-body separation of external stores to provide a foundation for separation strategy design and safe separation research.

[0003] CTS (Collision-Swept Aerodynamics Test) is a ground-based testing method for obtaining the aerodynamic and trajectory characteristics of external attachment separation under complex disturbance flow fields. It employs a combination of static force measurement and dynamic equation solving to progressively acquire the separation aerodynamic loads and trajectory. Its advantages include the ability to accurately set separation state parameters as needed and to accurately obtain static aerodynamic loads and separation trajectories. Its disadvantage is the lack of measurement of dynamic aerodynamic loads; in the absence of dynamic aerodynamic load measurement, corrections are typically made by setting dynamic derivative parameters.

[0004] Another experimental technique used for studying multibody separation problems is the launch test. This method generates initial separation velocity and angular velocity by launching a model, which then moves freely under wind tunnel conditions. The separation trajectory is captured using high-speed photography. Its advantage lies in simulating a dynamic separation process, taking into account dynamic aerodynamic load effects. Its disadvantages include the difficulty in accurately simulating the initial separation velocity and angular velocity with poor repeatability; the inability to obtain comprehensive images of the model under high-speed photography, making it difficult to obtain a six-degree-of-freedom motion trajectory; and the image distortion problem caused by non-uniform flow fields, which is difficult to resolve through image calibration.

[0005] CTS testing and deployment testing are complementary in terms of their advantages and disadvantages. Therefore, it is necessary to explore a testing method that combines the advantages of both CTS testing and deployment testing. Summary of the Invention

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

[0007] Firstly, a dynamic CTS testing method is provided, including:

[0008] (1) The structure of the real external object is reduced according to the size scaling relationship to obtain the external object model. Based on the dynamic similarity relationship, the CTS test parameters of the external object model are determined, including the linear velocity and angular velocity of the model.

[0009] (2) Move the external attachment model to a safe position away from the parent model using a six-degree-of-freedom mechanism. Keep the attitude of the external attachment model at zero degrees. Once the wind tunnel flow field is stable, move the external attachment model to the initial separation position.

[0010] (3) Start the wind tunnel test, record the initial test time t(0), and calculate the speed command of the driving component of the six-degree-of-freedom mechanism based on the inverse velocity relationship of the six-degree-of-freedom mechanism using the linear velocity and angular velocity of the model obtained in step (1).

[0011] (4) The drive components move according to the calculated drive component speed command. 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 it 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 attitude, linear velocity, and angular velocity of the external attachment 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), calculate the speed command of the driving component of the six-degree-of-freedom mechanism 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 pose data of the external attachment model into the aerodynamic load and pose data of the real external attachment, save the data, and stop the test.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the linear velocity of the model... The model angular velocity Where k q k is the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure. l k is a scaled-down representation of the size of the add-on model and the real add-on. m V is the ratio of the model's mass to the actual mass of the add-on. f Let ω be the linear velocity of the actual external object at the initial moment. f This represents the angular velocity of the actual external object at the initial moment.

[0015] In conjunction with the first aspect, in some implementations of the first aspect, the CTS test parameters also include model mass and model virtual gravity, and model moment of inertia, among which...

[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 k is a scaled-down representation of the size of the add-on model and the real add-on. t k represents the conversion ratio between experimental and actual separation times. m m is the ratio of the model's mass to the actual mass of the add-on. f To ensure the actual quality of external items, I f k represents the actual moment of inertia of the external attachment. m The mass of the add-on model is the ratio of the mass of the actual add-on, and g is the acceleration due to gravity.

[0020] In conjunction with the first aspect, in some implementations of the first aspect, the conversion ratio k between the experimental separation time and the actual separation time... t The wind tunnel parameter response time is determined based on the maximum value t1 among the flow field stabilization time, balance response time, and data acquisition time. t1 is then multiplied by n to obtain the experimental separation time t. ex According to the actual separation time t f Determine the conversion ratio k between experimental separation time and actual separation time. t =t ex / t f .

[0021] In conjunction with the first aspect, in some implementations of the first aspect, the safe position refers to the position where the external object model will not collide with the parent model due to vibration under wind load.

[0022] In conjunction with the first aspect, in some implementations of the first aspect, 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.

[0023] In conjunction with the first aspect, in some implementations of the first aspect, the method employs the velocity inverse solution relationship of a 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 drive component.

[0024] In conjunction with the first aspect, in certain implementations of the first aspect, the conversion of the aerodynamic load and pose data of the external attachment model into the aerodynamic load and pose data of the actual external attachment includes:

[0025] Based on the ratio k of wind tunnel dynamic pressure to actual flight dynamic pressure q The ratio of the size of the add-on model to the actual size of the add-on, k. l The aerodynamic load [F] of the external attachment model ex M ex Converted to aerodynamic load of a real external attachment [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, the conversion of the aerodynamic load and pose data of the external attachment model into the aerodynamic load and pose data of the actual external attachment includes:

[0027] Based on the ratio k between the size of the external attachment model and the actual size of the external attachment. l The displacement W of the external object model ex and stance Z ex Displacement W converted to a real add-on f =W ex / k l and stance Z f =Z ex .

[0028] In conjunction with the first aspect, in certain implementations of the first aspect, the conversion of the aerodynamic load and pose data of the external attachment model into the aerodynamic load and pose data of the actual external attachment includes:

[0029] Based on the conversion ratio k between experimental separation time and actual separation time t The test separation time t ex Convert to real separation time

[0030] Compared with the prior art, the solution provided in this application has at least the following beneficial technical effects:

[0031] 1. Compared with the existing CTS test methods, the dynamic CTS test method of the present invention uses the external attachment model to move through dynamic similarity during the test, and adopts dynamic force measurement to obtain the aerodynamic load of the external attachment model in motion state. This makes up for the deficiency of traditional CTS test methods in that they cannot directly measure dynamic aerodynamic loads, and improves the accuracy of multibody separation simulation.

[0032] 2. Compared with the position control mode of traditional CTS test in the prior art, the dynamic CTS test method of the present invention uses velocity mode to control the movement of the external object model, which shortens the test time and increases the number of test trajectory points, thereby providing more research data for multi-body separation problems;

[0033] 3. Compared with the existing drop test, the dynamic CTS test method of the present invention can easily set 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 also greatly improved compared with the drop test, making up for the shortcomings of the drop test and improving the test accuracy of the multibody separation test. Attached Figure Description

[0034] Figure 1 This is a flowchart of a dynamic CTS test. Detailed Implementation

[0035] The present application will now be described in further detail 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): The structure of the real external object is reduced in size according to the scaling relationship to obtain the external object model. Based on the dynamic similarity relationship, the CTS test parameters of the external object model are determined, including the model linear velocity and the model angular velocity.

[0038] Using parameters such as the size ratio between the external attachment model and the real external attachment, the conversion ratio of the experimental separation time to the actual separation time, the mass of the real external attachment, the moment of inertia of the real external attachment, the linear velocity of the real external attachment, and the angular velocity of the real external attachment, calculate the model mass and virtual mass, the model moment of inertia, the model linear velocity, and the model angular velocity, and fill in the CTS test parameters 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 velocity

[0043] Model angular velocity

[0044] Where k q k is the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure. l k is a scaled-down representation of the size of the add-on model and the real add-on. t m is the conversion ratio between experimental separation time and actual separation time. f To ensure the actual quality of external items, I f k represents the actual moment of inertia of the external attachment. m V is the ratio of the mass of the add-on model to the mass of the actual add-on. f Let ω be the linear velocity of the actual external object at the initial moment. f Let g be the angular velocity of the actual external object at the initial moment, and g be the acceleration due to gravity.

[0045] In some embodiments, the conversion ratio k between experimental separation time and actual separation time t The response time 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 logger acquisition time. t1 is then multiplied by n to obtain the test separation time t. ex ,Right now:

[0046] t ex =t1*n

[0047] Based on the actual separation time t f Determine the conversion ratio k between experimental separation time and actual separation time. t for:

[0048] k t =t ex / t f

[0049] Step (2): Move the external attachment model to a safe position away from the parent model using a six-degree-of-freedom mechanism. Keep the attitude of the external attachment model at zero degrees. Once the wind tunnel flow field is stable, move the external attachment model to the initial separation position.

[0050] A safe position refers to a location where the attached model will not collide with the parent model due to vibration under wind load. In some embodiments, the safe position is where the attached model is below the aircraft model, at a distance H from the lower surface of the aircraft model. S .

[0051] Step (3): Start the wind tunnel test, record the initial test time t(0), and calculate the model linear velocity V obtained in step (1). ex (0) and model angular velocity ω ex (0), calculate the speed command of the drive component of the six-degree-of-freedom mechanism [S1(0),S2(0),S3(0),S4(0),S5(0),S6(0)] based on the inverse velocity 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 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.

[0053] In step (4), the drive component moves according to the calculated speed command. 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 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), using 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 command [S1(i),S2(i),S3(i),S4(i),S5(i),S6(i)] of the six-degree-of-freedom mechanism drive component based on the inverse velocity relationship of the six-degree-of-freedom mechanism.

[0055] In some embodiments, the velocity inverse relationship of a 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 drive components.

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

[0057] In some embodiments, the test requires a test time of t. ex Based on the ratio k of wind tunnel dynamic pressure to actual flight dynamic pressure q The ratio of the size of the add-on model to the actual size of the add-on, k. l The aerodynamic load [F] of the external attachment model ex M ex Converted to aerodynamic load of a real external attachment [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] Based on the ratio k between the size of the external attachment model and the actual size of the external attachment. l The displacement W of the external object model ex and stance Z ex Displacement W converted to a real add-on f and stance Z f ,in

[0061] W f =W ex / k l

[0062] Z f =Z ex

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

[0064]

[0065] This method combines the advantages of accurate aerodynamic load measurement and convenient separation parameter setting in CTS experiments with the advantage of dynamic similarity in deployment experiments, providing a more effective experimental means for the study of multibody separation problems.

[0066] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can 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 should be determined by the scope defined in the claims of the present invention.

Claims

1. A dynamic CTS test method, characterized in that: include: (1) The structure of the real external store is reduced according to the size reduction ratio to obtain the external store model. According to the dynamic similarity relationship, the CTS test parameters of the external store model are determined, including the model linear velocity and model angular velocity; (2) Move the external attachment model to a safe position away from the mother model through the six-degree-of-freedom mechanism, keep the attitude of the external attachment model at zero degrees, and wait until the wind tunnel flow field is stable, then 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 driving component according to 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 command, 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, substitutes the wind tunnel aerodynamic parameter and aerodynamic load data into the six-degree-of-freedom flight dynamics equation and kinematic equation, and calculates the posture, 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 driving 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 line speed The model angular velocity where k q is the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure, k 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 real external attachment mass, V f is the linear velocity of the real 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 quality 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 is the ratio of wind tunnel dynamic pressure to actual flight dynamic pressure, k 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 gravitational acceleration.

4. The method according to claim 1, characterized in that: The conversion ratio k between the experimental separation time and the actual separation time t Determined by 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 collection 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, characterized in that The safe position refers to a 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 solution 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 driving component of the six-degree-of-freedom mechanism.

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 the aerodynamic load and posture data of the real external attachment comprises: 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 the aerodynamic load and posture data of the real external attachment comprises: According to the ratio k between the size of the external attachment model and the actual size of the external attachment 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 the aerodynamic load and posture data of the real external attachment comprises: 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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