CN114001892B - Time synchronization method between free jet test measurement systems - Google Patents

Abstract

The application relates to a time synchronization method between measurement systems of a free jet test, belongs to the field of vibration measurement of aircrafts, and solves the problems of complex system and high cost caused by the fact that in the prior art, each measurement system is required to receive a system instruction in time synchronization between measurement systems. The method comprises the following steps: arranging a plurality of vibration sensors and a plurality of noise sensors in the test piece, wherein each vibration sensor is connected to one vibration measuring system, each noise sensor is connected to one noise measuring system, and one system is optionally connected with a test bed controller from the measuring systems; performing free jet flow test on the test piece, sending a timing system instruction by a controller, receiving the instruction by a measurement system connected with the controller, and determining a timing system zero point according to the instruction; acquiring a vibration measurement curve and a noise measurement curve of each measurement system; determining the moment corresponding to the first peak value of the test recovery stage in each curve; and carrying out time synchronization on the measurement system according to the first peak time of the recovery stage of each measurement curve test.

Description

A time synchronization method between free jet test measurement systems

Technical field

The invention belongs to the field of aircraft vibration measurement, and in particular relates to a time synchronization method between free jet test measurement systems.

Background technique

Since the free jet test can simulate the state of the engine in a real flight environment on the ground, the flight power device, air intake, etc. will be tested using the engine's high-altitude simulated free jet test.

In free jet tests, vibration and noise environments are generally measured. Both vibration and noise environments require high sampling rates for measurement. The amount of measurement data is large, and multiple measurement systems are often used. The measurement data are generally shown in Figure 1 and Figure As shown in 2, in order to facilitate analysis, the data measured by each measurement system need to be analyzed using a unified time coordinate. Generally, each measurement system is used to collect unified timing instructions to establish the timing relationship between the measurement systems. This requires the addition of additional devices, making the system relatively complex and increasing the test cost. Some experiments cannot collect timing instructions in each measurement system due to limited measurement resources or the inability to output timing instructions to multiple measurement systems, making it difficult to establish timing relationships among multiple measurement systems.

Contents of the invention

In view of the above analysis, embodiments of the present invention aim to provide a time synchronization method between free jet test measurement systems to solve the complex device and test cost caused by the existing time synchronization method that requires each measurement system to collect timing instructions. high problem.

On the one hand, embodiments of the present invention provide a time synchronization method between free jet test measurement systems, including the following steps:

Arrange multiple vibration sensors and multiple noise sensors in the test piece, each vibration sensor is connected to a vibration measurement system, each noise sensor is connected to a noise measurement system, from the multiple vibration measurement systems and multiple noise measurement systems Select any system to connect to the test bench controller;

A free jet test is performed on the test piece, the controller issues a timing command, and the above-mentioned measurement system connected to the controller receives the command and determines the timing zero point based on the command;

Obtain the vibration measurement curves of each vibration measurement system and the noise measurement curves of each noise measurement system;

Determine the moment corresponding to the first peak in the test recovery phase in each vibration measurement curve and noise measurement curve;

The above-mentioned measurement system is time synchronized according to the moment corresponding to the first peak value in the recovery phase of each above-mentioned measurement curve test.

Further, the time synchronization of the above-mentioned measurement system based on the first peak moment of the test recovery phase of each of the above-mentioned measurement curves includes:

Find the time corresponding to the first peak value in the test recovery phase corresponding to the measurement system connected to the controller, record it as tx, record the time corresponding to the first peak value of other measurement systems as t1, t2,...tn, record tx-t1, tx-t2,...,tx-tn are used as the time adjustment amounts of the corresponding measurement systems, and time synchronization between measurement systems is performed based on the above time adjustment amounts.

Further, the time synchronization between measurement systems based on the above time adjustment amount includes: the corresponding measurement system adds the time adjustment amount based on the original time coordinate as the time after time synchronization.

Further, the free jet test includes three stages, which are in chronological order: preparation stage, effective stage, and recovery stage.

Further, the acquisition of vibration measurement curves of each vibration measurement system and noise measurement curves of each noise measurement system includes:

During the test process, the vibration measurement system and the noise measurement system collect the vibration signals and noise signals measured by the vibration sensors and noise sensors in real time;

After filtering and normalizing the vibration signal and noise signal, a vibration measurement curve and a noise measurement curve are obtained.

Furthermore, during the test process, the vibration measurement system and noise measurement system collect the vibration signals and noise signals measured by the vibration sensor and noise sensor in real time, and stop collecting after at least 10 seconds during the test recovery phase to ensure that the first vibration peak value in the test recovery phase is collected. and noise peaks.

Furthermore, when the test reaches the effective stage, the test bench controller issues a timing command and maintains it until it is canceled at the end of the effective stage of the test.

Further, the above-mentioned measurement system connected to the controller receives the instruction and determines the time system zero point according to the instruction, including: the measurement system connected to the controller receives the time system instruction, and the measurement system corresponding to the rising edge of the voltage of the time system instruction is received. The time is set to zero point of time system.

Further, the noise sensor and the vibration sensor are installed in the same closed space in the test piece. The vibration sensor is installed on the mounting bracket of each component in the closed space of the test piece to measure vibration data in the X, Y, and Z directions. The noise sensor is installed It is used to measure the noise signal in the closed space of the test piece at a position on the inner wall of the closed space and at a certain distance from the inner wall.

Further, the vibration sensor has a measurement range of 0.3Hz-4000Hz; the noise sensor has a measurement range of 130dB-160dB and the frequency range is 0.3Hz-4000Hz.

Compared with the prior art, the present invention can achieve at least the following beneficial effects:

For the noise measurement and vibration measurement in the free jet test, it was proposed for the first time that the timing relationship between the measurement systems can be determined by identifying the noise and vibration peaks after the test without collecting timing instructions from each measurement system separately, solving the problem The problem of timing determination of vibration and noise data collected by multiple measurement systems. The results can be extended to vibration and noise measurements in various aircraft free jet tests. By using this method, it is possible to determine the temporal relationship between multiple measurement systems, reduce the complexity of the measurement system, and reduce the test cost.

In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination solutions. Additional features and advantages of the invention will be set forth in the description which follows, and in part, some advantages will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and obtained by the disclosure particularly pointed out in the description and drawings.

Description of drawings

The drawings are for the purpose of illustrating specific embodiments only and are not to be construed as limitations of the invention. Throughout the drawings, the same reference characters represent the same components.

Figure 1 is a schematic diagram of the noise measurement curve;

Figure 2 is a schematic diagram of the vibration measurement curve;

Figure 3 is a schematic flow chart of the time synchronization method between various measurement systems in this application;

Figure 4 is a block diagram of the free test measurement system of this application;

Figure 5 is a schematic diagram of the noise measurement curve of the noise measurement system 1 of the present application;

Figure 6 is a schematic diagram of the noise measurement curve of the noise measurement system 2 of the present application;

Figure 7 is a schematic diagram of the vibration measurement curve of the vibration measurement system 1 of the present application;

Figure 8 is a schematic diagram of the vibration measurement curve of the vibration measurement system 2 of the present application;

Figure 9 is a schematic diagram of the noise measurement curve of the noise measurement system of this application after 2-time integration;

Figure 10 is a schematic diagram of the vibration measurement curve after 1 time of the vibration measurement system of this application;

Figure 11 is a schematic diagram of the vibration measurement curve of the vibration measurement system of this application after 2-time system;

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

A specific embodiment of the present invention discloses a time synchronization method between free jet test measurement systems. As shown in Figure 3, the method includes the following steps:

S1. Arrange multiple vibration sensors and multiple noise sensors in the test piece. Each vibration sensor is connected to a vibration measurement system, and each noise sensor is connected to a noise measurement system. From multiple vibration measurement systems and multiple noise measurements Select any system in the system to connect to the test bench controller;

S2. Conduct a free jet test on the test piece, the controller issues a timing command, and the above-mentioned measurement system connected to the controller receives the command and determines the timing zero point based on the command;

S3. Obtain the vibration measurement curves of each vibration measurement system and the noise measurement curves of each noise measurement system;

S4. Determine the moment corresponding to the first peak in the test recovery phase in each vibration measurement curve and noise measurement curve;

S5. Time synchronize the above-mentioned measurement system according to the moment corresponding to the first peak value in the test recovery phase of each of the above-mentioned measurement curves.

Compared with the existing technology, the time synchronization method between free jet test measurement systems provided by this embodiment determines the test recovery stage of each vibration measurement curve and noise measurement curve by obtaining vibration measurement curves and noise measurement curves of multiple measurement systems. Time synchronization between measurement systems is performed at the moment corresponding to the first vibration peak and noise peak. Compared with the existing technology, only one measurement system is required to receive timing instructions, and other measurement systems correspond to the first vibration peak and noise peak. Time synchronization of measurement system components can be achieved at the moment.

During implementation, the test measurement system used is shown in Figure 4. The test measurement system mainly includes: free jet test bench, test piece, test bench controller, vibration measurement system, noise measurement system, vibration sensor, and noise sensor. The test piece is placed on the free jet test bench, and the vibration sensor and noise sensor are installed in the test piece to measure the vibration data and noise data of the test piece during the test.

Each step is introduced in detail below:

Step S1. Arrange multiple vibration sensors and multiple noise sensors in the test piece. Each vibration sensor is connected to a vibration measurement system, and each noise sensor is connected to a noise measurement system. From the multiple vibration measurement systems and multiple noise Select any system in the measurement system to connect to the test bench controller;

During implementation, two vibration sensors and two noise sensors are arranged, and accordingly, two vibration measurement systems and two noise measurement systems are set up; the number of the above vibration sensors and noise sensors can be set according to actual needs.

Specifically, the test piece is usually an aircraft. The aircraft includes multiple cabin sections. Each cabin section is a closed space, and the vibration and noise environment in each space is different. Therefore, when collecting vibration and noise data, Vibration and noise data should be collected in the same closed space. Therefore, when installing the sensor, the noise sensor and the vibration sensor should be installed in the same closed space in the test piece. The vibration sensor should be installed on the mounting bracket of each component in the closed space of the test piece. It is used to measure vibration data in three directions:

Using the above installation method, the collected vibration data and noise data can originate from the same closed space, which facilitates subsequent analysis of different closed space environments.

After installing each vibration sensor and noise sensor, connect each vibration sensor to a vibration measurement system and each noise sensor to a noise measurement system.

Select one system among all vibration measurement systems and noise measurement systems to connect to the test bench controller to receive timing instructions from the controller. During implementation, as shown in Figure 4, the noise measurement system 1 is selected to be connected to the test bench controller. Of course, you can also choose other measurement systems to connect to the test bench controller, and the effect will be the same.

In this application, only one measurement system needs to be connected to the controller to receive timing instructions, and there is no need for all measurement systems to receive timing instructions. Therefore, there is no need to add additional devices, and the system is simple and easy to implement.

Specifically, according to the actual test environment, the selected vibration sensor has a measurement range of ±500g and a frequency range of 0.3Hz-4000Hz; the noise sensor has a measurement range of 130dB-160dB and a frequency range of 0.3Hz-4000Hz.

After each device in the test system is connected, step S2 can be performed;

Step S2: Conduct a free jet test on the test piece, the controller issues a timing command, and the above-mentioned measurement system connected to the controller receives the command and determines the timing zero point according to the command;

Specifically, the test process includes three stages, in chronological order: preparation stage, effective stage, and recovery stage.

When the test reaches the valid stage, the test bench controller issues a timing command and holds it until it is canceled at the end of the test valid stage. Specifically, the timing command is a voltage signal. When the timing command is issued, the voltage jumps from 0 to 28V and remains there. When the timing command is cancelled, the voltage jumps from 28V to 0V.

The noise measurement system connected to the controller receives the above time system instructions and determines the time system zero point according to the instructions.

Specifically, the above-mentioned noise measurement system connected to the controller receives the timing command, and sets the time of the noise measurement system corresponding to the rising edge of the voltage of the timing command as the timing zero point.

Step S3: Obtain the vibration measurement curves of each vibration measurement system and the noise measurement curves of each noise measurement system;

Specifically, the sampling frequency of the vibration measurement channel in each vibration measurement system is set to 5120Hz, using low-pass filtering, and the filtering frequency is 2000Hz. The sampling frequency of the noise channel in each noise measurement system is 30KHz, using low-pass filtering, and the filtering frequency is 10KHz.

During the test process, the vibration measurement system and noise measurement system collect vibration signals and noise signals from the vibration sensor and noise sensor in real time, continue to collect data from the test preparation stage to the test recovery stage, and stop collecting after at least 10 seconds in the test recovery stage. To ensure that the first vibration peak and noise peak in the test recovery phase are collected.

After collecting the above vibration signals and noise signals, the vibration measurement system and the noise measurement system filter and normalize the vibration signals and noise signals respectively to obtain the vibration measurement curve and the noise measurement curve, as shown in Figures 5 to 8. As shown in Figure 5 to Figure 8, the noise measurement curves and vibration measurement curves obtained by the noise measurement systems 1 and 2 and the vibration measurement systems 1 and 2 are shown.

S4. Determine the moment corresponding to the first peak in the test recovery phase in each vibration measurement curve and noise measurement curve;

As shown in Figure 5-8, for the noise measurement curve obtained by noise measurement system 1, the first noise peak value in the test recovery phase is 0.4223, and the corresponding time is 30.12s; for noise measurement system 2, the first noise peak value in the test recovery phase is 1, the corresponding time is 24.37; for vibration measurement system 1, the first vibration peak value in the test recovery phase is -1, and the corresponding time is 1.649; for vibration measurement system 2, the first vibration peak value in the test recovery phase is -1, corresponding to The time is 10.97;

It can be seen that the times in the above-mentioned measurement curves are not unified, and when these data are subsequently used for calculations, the times of these data need to be unified, so the time of each measurement system needs to be synchronized.

S5. Time synchronize the above-mentioned measurement system according to the first peak moment in the test recovery phase of each of the above-mentioned measurement curves.

After conducting many free jet tests and analyzing the test data, the inventor found that in the early recovery stage of the free jet test bench, the physical process of its operation will cause short-term strong noise and strong vibration, so this characteristic can be exploited. Time statistics of each measurement system.

Specifically, find the first peak moment in the test recovery phase corresponding to the measurement system connected to the controller, record it as tx, record the first peak moments of other measurement systems as t1, t2,...tn, record tx-t1, tx -t2,...,tx-tn are used as the time adjustment amounts of the corresponding measurement systems, and time synchronization between measurement systems is performed based on the above time adjustment amounts.

Specifically, time synchronization between measurement systems is performed in the following manner: the corresponding measurement system adds the time adjustment amount based on the original time coordinates as the time after time synchronization.

In a specific real-time example, the measurement system connected to the controller is found to be noise measurement system 1. The time tx corresponding to the first noise peak in the test recovery phase in the noise measurement curve obtained by this system is 30.12s. Noise measurement system 2, The first peak moments in the test recovery phase corresponding to vibration measurement system 1 and vibration measurement system 2 are 24.37s, 1.649s, and 10.97s respectively, then (30.12-24.37)s, (30.12-1.649)s, (30.12-10.97) s serves as the time adjustment amount of noise measurement system 2, vibration measurement system 1, and vibration measurement system 2.

Noise measurement system 2, vibration measurement system 1, and vibration measurement system 2 are added to the above time adjustment amount based on the original time coordinates to obtain the post-time system time, as shown in Figure 9-11. After time synchronization of noise measurement system 2, vibration measurement system 1, and vibration measurement system 2, the time of the vibration measurement curve and noise measurement curve obtained are synchronized with the noise measurement curve obtained by noise measurement system 1, which facilitates subsequent data analysis and processing. .

Those skilled in the art can understand that all or part of the process of implementing the method of the above embodiments can be completed by instructing relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. Wherein, the computer-readable storage medium is a magnetic disk, an optical disk, a read-only memory or a random access memory, etc.

The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can easily think of changes or modifications within the technical scope disclosed in the present invention. All substitutions are within the scope of the present invention.

Claims (7)

1. A time synchronization method between free jet test measurement systems, which is characterized by: including the following steps: Arrange multiple vibration sensors and multiple noise sensors in the test piece, each vibration sensor is connected to a vibration measurement system, each noise sensor is connected to a noise measurement system, from the multiple vibration measurement systems and multiple noise measurement systems Select any system to connect to the test bench controller, where, The noise sensor and the vibration sensor are installed in the same closed space in the test piece. The vibration sensor is installed on the mounting bracket of each component in the closed space of the test piece to measure vibration data in the X, Y, and Z directions. The noise sensor is installed in the closed space. On the inner wall of the space and at a certain distance from the inner wall, it is used to measure the noise signal in the enclosed space of the test piece; The test piece is subjected to a free jet test, and the controller issues a timing command. The above-mentioned measurement system connected to the controller receives the command and determines the timing zero point according to the command, where, The free jet test includes three stages, in chronological order: preparation stage, effective stage, recovery stage, When the test reaches the valid stage, the test bench controller issues a timing command and holds it until it is canceled at the end of the test valid stage; Obtain the vibration measurement curves of each vibration measurement system and the noise measurement curves of each noise measurement system; Determine the moment corresponding to the first peak in the test recovery phase in each vibration measurement curve and noise measurement curve; The above-mentioned measurement system is time synchronized according to the moment corresponding to the first peak value in the recovery phase of each above-mentioned measurement curve test. 2. The time synchronization method according to claim 1, characterized in that the time synchronization of the measurement system according to the first peak moment of the test recovery phase of each measurement curve includes: Find the time corresponding to the first peak value in the test recovery phase corresponding to the measurement system connected to the controller, record it as tx, record the time corresponding to the first peak value of other measurement systems as t1, t2,...tn, record tx-t1, tx-t2,...,tx-tn are used as the time adjustment amounts of the corresponding measurement systems, and time synchronization between measurement systems is performed based on the above time adjustment amounts. 3. The time synchronization method according to claim 1, wherein the time synchronization between measurement systems according to the time adjustment amount includes: the corresponding measurement system synchronizes the time adjustment amount with the time adjustment amount based on the original time coordinates. Added together, it is used as the time after time synchronization. 4. The time synchronization method according to claim 1, wherein said obtaining the vibration measurement curves of each vibration measurement system and the noise measurement curves of each noise measurement system includes: During the test process, the vibration measurement system and the noise measurement system collect the vibration signals and noise signals measured by the vibration sensors and noise sensors in real time; After filtering and normalizing the vibration signal and noise signal, a vibration measurement curve and a noise measurement curve are obtained. 5. The time synchronization method according to claim 1, characterized in that during the test process, the vibration measurement system and the noise measurement system collect the vibration signals and noise signals measured by the vibration sensor and the noise sensor in real time, and collect them after at least 10s during the test recovery phase. Stop the acquisition to ensure that the first vibration peak and noise peak in the test recovery phase are collected. 6. The time synchronization method according to claim 1, characterized in that the above-mentioned measurement system connected to the controller receives the instruction and determines the time system zero point according to the instruction includes: the measurement system connected to the controller receives the time system instruction, Set the time of the measurement system corresponding to the rising edge of the time system command voltage as the time system zero point. 7. The time synchronization method according to claim 1, characterized in that the vibration sensor has a measuring range of ±500g and a frequency range of 0.3Hz-4000Hz; the noise sensor has a measuring range of 130dB-160dB and a frequency range of 0.3Hz- 4000Hz.