Method for quantitatively judging operation stability of vibration mechanism in dynamic derivative test

Abstract

The invention discloses a method for quantitatively judging the operation stability of a dynamic derivative test vibration mechanism, relates to the technical field of fault prediction, and aims to solve the problem that no unified judgment index exists for judging whether a test mechanism has a fault or not in an existing high-speed wind tunnel dynamic derivative test. According to the method, a normalization idea is adopted, firstly, angular displacement voltage value data is subjected to normalization processing, and angular displacement voltage value data scales under different mechanisms or different working conditions are unified; then, calculating a single-cycle residual sum of squares between the sine curve and a standard sine curve; and finally, judging whether the mechanism breaks down or not by evaluating whether the residual sum of squares of a single period exceeds an interpretation index or not and whether the angular displacement amplitude is out of tolerance or not. The invention provides important support for improving the equipment performance, prolonging the service life and ensuring the safety in the aerospace field.

Description

Technical Field

[0001] The invention relates to the technical field of fault prediction, and in particular to a method for quantitatively judging the operating stability of a vibration mechanism in a dynamic derivative test. Background Art

[0002] The high-speed wind tunnel forced vibration dynamic derivative test technology relies on the dynamic derivative vibration mechanism to make the model perform standard sinusoidal simple harmonic motion, and obtains dynamic derivative data by measuring the torque and angle history of the model under the conditions of set frequency and amplitude. The sinusoidality of the dynamic derivative mechanism vibration is the key to whether the dynamic derivative test can be accurately measured, and determines the accuracy of the dynamic derivative test results.

[0003] At present, the means of evaluating the vibration stability of the dynamic derivative test mechanism is to conduct a test mechanism debugging test on the ground. Its main purpose is to debug the test mechanism to the optimal state before the hole test. The main debugging content includes adjusting the model weight, determining the optimal test frequency, optimizing the mechanism gap, etc. The usual measurement indicator is that the mechanical damping value reaches the minimum and stable state. However, due to the constraints of different models, different mechanisms and other conditions, there is no specific quantifiable evaluation indicator for the mechanical damping size under air vibration conditions.

[0004] In addition, during the high-speed wind tunnel high-angle dynamic derivative test, the reciprocating transmission components of the dynamic derivative test mechanism will inevitably wear or even deform under high-load conditions, making the mechanism movement gap larger and larger, resulting in a non-sinusoidal trend in the vibration angular displacement, which seriously affects the repeatability accuracy of the test results. Therefore, it is usually necessary to manually monitor and rely on experience to analyze the data to determine whether the worn parts need to be replaced, but the test personnel may omit or judge inconsistent experience / standards during the analysis process, affecting the reliability of the data, and even due to untimely monitoring, the test vehicles may be scrapped in batches. Summary of the invention

[0005] In order to solve the problem that there is no unified evaluation index for whether a test mechanism fails in the existing high-speed wind tunnel dynamic derivative test, the present invention provides a method for quantitatively judging the operating stability of a vibration mechanism in a dynamic derivative test, comprising the following steps: S1. Perform the first fitting on the original angular displacement voltage value signal, and then obtain the average voltage amplitude through parameter identification; S2. Determine whether the angular displacement amplitude exceeds the tolerance. If it exceeds the design value by 5%, it is necessary to check whether the dynamic derivative test vibration mechanism is overloaded; S3. normalizing the original angular displacement voltage value signal to obtain a normalized angular displacement voltage value signal; S4. Perform a second fitting on the normalized angular displacement voltage value signal to obtain a quadratic fitting standard sine curve; S5. Obtain the residual sum of squares between the normalized angular displacement voltage value signal and the quadratic fitting standard sine curve under a single vibration cycle; S6. Determine whether the residual sum of squares in a single cycle is greater than the evaluation index. If so, check whether the dynamic derivative vibration mechanism has any abnormality.

[0006] Furthermore, the first fitting is performed on the original angular displacement voltage value signal: ; To achieve, is the original angular displacement voltage value signal, is the average voltage amplitude to be identified, is the nominal vibration frequency, To collect time series, is the first cycle zero-crossing moment, is the DC component.

[0007] Further, in S2, the angular displacement amplitude is obtained by: ; Obtain, among which, is the angular displacement amplitude, is the angular displacement calibration coefficient.

[0008] Further, in S3, the normalized angular displacement voltage value signal is obtained by: ; Obtain, among which, is the normalized angular displacement voltage value signal.

[0009] Furthermore, in S4, the quadratic fitting of the standard sine curve is performed by: ; To achieve, is the quadratic fit to the standard sine curve, is the average voltage amplitude of the normalized angle element voltage signal, is the first cycle zero-crossing moment of the normalized angle element voltage signal, is the DC component of the normalized angle element voltage signal.

[0010] Furthermore, in S5, in a single vibration cycle, the residual square sum between the normalized angular displacement voltage value signal and the quadratic fitting standard sine curve is calculated by: ; Obtain, among which, For the i The angular displacement voltage value signal after normalization of the cycle, For the i The quadratic fit of the standard sine curve is is the residual sum of squares in a single period, N For cycle.

[0011] The beneficial effects of the present invention are: 1. It can establish a unified evaluation standard between different mechanisms, different angle balances, different loads, different vibration frequencies, different sampling times and other working conditions; 2. It is convenient and fast, reduces the influence of human experience, can detect faults in time, ensure the reliability of data, and avoid batch scrapping of vehicles; 3. It is helpful to find problems at the first time, thereby reducing the burden on aerodynamic analysts, improving test efficiency and ensuring data quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 To determine the stability of the mechanism operation flow chart; Figure 2 This is the voltage value curve of the angular displacement of the mechanism with better sinusoidal performance; Figure 3 This is the angular displacement voltage value curve of a mechanism with poor sinusoidality. DETAILED DESCRIPTION

[0013] In order to make the technical solutions and advantages of the embodiments of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0014] Embodiment 1, combination Figure 1 To illustrate this embodiment, the present invention provides a method for quantitatively determining the running stability of a vibration mechanism in a dynamic derivative test, comprising the following steps: S1. Perform the first fitting on the original angular displacement voltage value signal, and then obtain the average voltage amplitude through parameter identification; S2. Determine whether the angular displacement amplitude exceeds the tolerance. If it exceeds the design value by 5%, it is necessary to check whether the dynamic derivative test vibration mechanism is overloaded; S3. normalizing the original angular displacement voltage value signal to obtain a normalized angular displacement voltage value signal; S4. Perform a second fitting on the normalized angular displacement voltage value signal to obtain a quadratic fitting standard sine curve; S5. Obtain the residual sum of squares between the normalized angular displacement voltage value signal and the quadratic fitting standard sine curve under a single vibration cycle; S6. Determine whether the residual sum of squares in a single cycle is greater than the evaluation index. If so, check whether the dynamic derivative vibration mechanism has any abnormality.

[0015] Specifically, the evaluation index is the optimal air vibration value of the vibration mechanism in the test or the empirical value of multiple statistics. The present invention improves the judgment accuracy and efficiency by monitoring the angular vibration waveform, evaluating the operation and debugging of the test mechanism, the replacement requirements of easily worn parts, the rationality of the repeatability of the train, and the selection of the optimal test frequency. The present invention adopts the "normalization" idea. After completing the first fitting of the original angular displacement voltage value signal and obtaining the average voltage amplitude, if the angular displacement amplitude does not exceed 5% of the design value (otherwise it is necessary to check whether the vibration mechanism is overloaded), the original angular displacement voltage value data is first normalized to unify the angular displacement voltage value data scale under different mechanisms or different working conditions; then, the normalized angular displacement voltage value signal is used to generate a quadratic fitting standard sine curve through a quadratic fitting algorithm, and based on this, the residual square sum between the normalized angular displacement voltage value signal and the quadratic fitting standard sine curve in a single vibration cycle is calculated. Finally, by evaluating whether the residual square sum under a single cycle exceeds the judgment index, it is judged whether the mechanism is faulty.

[0016] The first fitting pass of the original angular displacement voltage value signal is: ; To achieve, is the original angular displacement voltage value signal, is the average voltage amplitude to be identified, is the nominal vibration frequency, To collect time series, is the first cycle zero-crossing moment, is the DC component.

[0017] In S2, the angular displacement amplitude is given by: ; Obtain, among which, is the angular displacement amplitude, is the angular displacement calibration coefficient.

[0018] In S3, the normalized angular displacement voltage value signal is obtained by: ; Obtain, among which, is the normalized angular displacement voltage value signal.

[0019] In S4, the quadratic fit to the standard sine curve is done by: ; To achieve, is the quadratic fit to the standard sine curve, is the average voltage amplitude of the normalized angle element voltage signal, is the first cycle zero-crossing moment of the normalized angle element voltage signal, is the DC component of the normalized angle element voltage signal.

[0020] In S5, in a single vibration cycle, the residual sum of squares between the normalized angular displacement voltage value signal and the quadratic fitting standard sine curve is calculated by: ; Obtain, among which, For the i The angular displacement voltage value signal after normalization of the cycle, For the i The quadratic fit of the standard sine curve is is the residual sum of squares in a single period, N For cycle.

[0021] Specific examples of results are shown in the attached Figure 2 With attached Figure 3 As shown, Figure 2 The normalized angular displacement voltage value signal is highly consistent with the quadratic fitting standard sine curve ( SSE Small), indicating that the mechanism operates stably and has low noise interference; Figure 3 The signal has significant distortion ( SSE Large), indicating that the vibration of the mechanism has become non-sinusoidal due to wear or increased clearance, and the fault needs to be checked.

Claims

1. A method for quantitatively determining the operating stability of a vibration mechanism in a dynamic derivative test, characterized in that: The following steps are involved: S1. Perform the first fitting on the original angular displacement voltage value signal, and then obtain the average voltage amplitude through parameter identification; S2. Determine whether the angular displacement amplitude exceeds the tolerance. If it exceeds the design value by 5%, it is necessary to check whether the dynamic derivative test vibration mechanism is overloaded; S3. normalizing the original angular displacement voltage value signal to obtain a normalized angular displacement voltage value signal; S4. Perform a second fitting on the normalized angular displacement voltage value signal to obtain a quadratic fitting standard sine curve; S5. Obtain the residual sum of squares between the normalized angular displacement voltage value signal and the quadratic fitting standard sine curve under a single vibration cycle; S6. Determine whether the residual sum of squares in a single cycle is greater than the evaluation index. If so, check whether the dynamic derivative vibration mechanism has any abnormality.

2. A method for quantitatively judging the running stability of a vibration mechanism by a dynamic derivative test according to claim 1, characterized in that: The first fitting pass of the original angular displacement voltage value signal is: ； To achieve, is the original angular displacement voltage value signal, is the average voltage amplitude to be identified, is the nominal vibration frequency, To collect time series, is the first cycle zero-crossing moment, is the DC component.

3. The method for quantitatively judging the running stability of a vibration mechanism by a dynamic derivative test according to claim 1, characterized in that: In S2, the angular displacement amplitude is given by: ； Obtain, among which, is the angular displacement amplitude, is the angular displacement calibration factor.

4. The method for quantitatively judging the running stability of a vibration mechanism by a dynamic derivative test according to claim 1, characterized in that: In S3, the normalized angular displacement voltage value signal is obtained by: ； Obtain, among which, is the normalized angular displacement voltage value signal.

5. The method for quantitatively judging the running stability of a vibration mechanism by a dynamic derivative test according to claim 1, characterized in that: In S4, the quadratic fit to the standard sine curve is done by: ； To achieve, is the quadratic fit to the standard sine curve, is the average voltage amplitude of the normalized angle element voltage signal, is the first cycle zero-crossing moment of the normalized angle element voltage signal, is the DC component of the normalized angle element voltage signal.

6. The method for quantitatively judging the running stability of a vibration mechanism by a dynamic derivative test according to claim 1, characterized in that: In S5, in a single vibration cycle, the residual sum of squares between the normalized angular displacement voltage value signal and the quadratic fitting standard sine curve is calculated by: ； Obtain, among which, For the i The angular displacement voltage value signal after normalization of the cycle, For the i The quadratic fit of the standard sine curve is is the residual sum of squares in a single period, N For cycle.

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