A method and system for simultaneous measurement of displacement and pneumatic pressure

Abstract

The present application relates to a kind of displacement and pneumatic pressure synchronous measurement method and system, and the synchronous opening measurement of pressure scanning valve and the synchronous opening measurement of multi-channel dynamic signal data acquisition system are triggered by external trigger system, and pressure scanning valve and laser displacement meter can measure the pressure and displacement of all pressure points simultaneously;Since pressure scanning valve and single-channel piezoresistive differential pressure sensor can measure the pressure information of reference pressure point simultaneously, as more accurate basic signal reference data, the time difference of single-channel piezoresistive differential pressure sensor and pressure scanning valve pressure signal of reference pressure point is calculated by cross-correlation method and artificial alignment method, to carry out time sequence alignment to the displacement signal measured by laser displacement meter and the pneumatic pressure signal measured by pressure scanning valve, the time difference of measurement signal is calculated accurately, can significantly improve signal time sequence consistency, the final result obtained by synchronous measurement is more accurate, provides more reliable data support for subsequent vibration analysis.

Description

Technical Field

[0001] This invention relates to the field of wind tunnel testing technology in the area of ​​bridge wind resistance, and in particular to a method and system for simultaneous measurement of displacement and aerodynamic pressure. Background Technology

[0002] Accurate measurement of unsteady aerodynamic loads on bridge components is a crucial step in studying wind-induced vibration. Segmental model wind tunnel testing is a commonly used method for determining unsteady aerodynamic loads. Forced vibration wind tunnel testing, in particular, uses specialized mechanical devices to drive a bridge model through simple harmonic vibrations with controllable frequency, amplitude, and phase, allowing for the identification of aerodynamic derivatives. This method offers advantages such as good repeatability of test signals, high signal-to-noise ratio, and high identification accuracy. Free vibration wind tunnel testing can reveal the time-varying aerodynamic loads during the amplitude divergence and decay of wind-induced vibrations.

[0003] The aerodynamic self-excited forces acting on the model are closely related to the model's wind-induced vibration motion, thus requiring simultaneous measurement of model displacement and aerodynamic forces. Currently, the mainstream method uses a multi-dimensional force balance, mounted at both ends of the model to directly measure the forces acting on it, and a laser displacement meter to measure the model's vibration displacement. The balance and displacement meter are then used with the same signal acquisition system to achieve simultaneous measurement of the model's vibration response and aerodynamic loads. However, the balance measures the resultant force signal of all external forces acting on the model, including static loads such as model gravity, installation stress, and static wind load, as well as dynamic loads such as inertial forces and aerodynamic forces. Inertial forces constitute the majority, making the extraction of self-excited forces a matter of subtracting a large number from a large number, often resulting in poor accuracy. This places high demands on the accuracy of the balance and the model's fabrication. Some researchers have integrated the balance into the model, measuring the forces acting on a localized part of the model's outer layer to reduce the proportion of inertial forces and increase the proportion of self-excited forces, thereby improving the accuracy of self-excited force extraction. However, this method is difficult and costly to manufacture.

[0004] Another method involves using an electronic pressure scanning valve to measure the pressure on the model surface and integrating it to obtain the model's aerodynamic self-excited force. This eliminates the need to consider the influence of external loads such as the model's own inertial force, offering advantages such as multiple channels, high accuracy, and the ability to obtain the instantaneous pressure distribution on the model surface. However, the pressure acquisition system using the pressure scanning valve is an integrated closed system, requiring two different dynamic data acquisition systems to acquire pressure and vibration signals separately during experiments. Some researchers have proposed using external signal commands to enable simultaneous acquisition by both systems; however, due to the unique working principle of the pressure scanning valve, the acquisition response time after receiving an external trigger command differs from that of the dynamic data acquisition system. Therefore, during dynamic force measurement, the force signal obtained by pressure integration exhibits a phase lag compared to the result of the balance force measurement method, making it difficult to accurately describe the aerodynamic effects of the structure and affecting the accuracy of aerodynamic derivative identification. Therefore, achieving high-precision time-synchronous measurement of structural vibration response and aerodynamic pressure is of great significance for the study of wind-induced vibration of bridge structures.

[0005] Chinese invention patent application CN105628334A discloses a synchronous pressure and vibration measurement system and its implementation method based on a gas elastic model. It uses a syringe as a calibrator and obtains the time difference between pressure and displacement data by moving a piston handle and measuring its displacement during the acquisition process. However, the piston handle motion has nonlinear characteristics, and the pressure data has significant noise, which can easily interfere with the time difference identification process and affect the accuracy of the analysis. In this patent, the time difference calculated from two cycles selected from n piston handle motion cycles differs by 4 ms. For models with frequencies above 10 Hz (i.e., periods less than 100 ms), such errors will significantly affect the time synchronization accuracy, potentially leading to misjudgments in subsequent wind-induced vibration analysis.

[0006] To address the aforementioned problems, this invention discloses a method and system for synchronous measurement of displacement and aerodynamic pressure. A fully automated electronic excitation and time-synchronized data acquisition system was developed, enabling time-synchronized acquisition of pressure and displacement signals and eliminating the time lag between the two signals, ensuring their time synchronization. This is helpful in understanding the distribution and evolution of aerodynamic pressure on the structural surface and the characteristics of aerodynamic self-excited forces during vibration, and is of great significance for research in fields such as post-flutter. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing synchronous pressure and vibration measurement methods, which have large errors in determining the time difference, and to provide a method and system for synchronous measurement of displacement and aerodynamic pressure.

[0008] In a first aspect, the present invention provides a method for simultaneous measurement of displacement and pneumatic pressure, comprising the following steps:

[0009] S1. Connect the external triggering system to the multi-channel dynamic signal data acquisition system and the pressure scanning valve via electrical signal lines; connect the multi-channel dynamic signal data acquisition system to the single-channel piezoresistive differential pressure sensor and the laser displacement gauge via electrical signal lines. Several pressure measurement points are arranged on the surface of the structural segment model, and a pressure measurement pipeline is installed at each pressure measurement point. One pressure measurement point is selected as a reference pressure measurement point. One end of the pressure measurement pipeline of the reference pressure measurement point is connected to the end of the pressure measurement pipeline through a tee pipe, and the other two ends are respectively connected to a certain channel of the pressure scanning valve and a single-channel piezoresistive differential pressure sensor. The remaining pressure measurement pipelines are connected to the pressure measurement points and one of the remaining channels of the pressure scanning valve. The laser displacement gauge is set at a position that can measure the displacement of the pressure measurement point, and the laser displacement gauge does not interfere with the movement of the structural segment model; S2. The multi-channel dynamic signal data acquisition system and the pressure scanning valve are simultaneously activated for measurement via an external triggering system. S3, the multi-channel dynamic signal data acquisition system measures the displacement of the pressure measurement points of the structural segment model through a laser displacement meter and simultaneously measures the pressure signal of the reference pressure measurement point through a single-channel piezoresistive differential pressure sensor; At the same time, the pressure scanning valve measures the pressure signals of all pressure measurement points arranged on the surface of the model; S4. The time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is calculated based on two methods: cross-correlation method and manual alignment method. Then, the displacement signal is time-corrected according to the time difference to obtain the final measurement result.

[0010] Preferably, in step S4, the time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is first calculated by computer based on the cross-correlation method; then, the time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is calculated by manual alignment method to achieve verification and obtain the final time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve; then, the displacement signal is time-corrected according to the time difference to obtain the final measurement result.

[0011] Preferably, the time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is calculated using the cross-correlation method in a MATLAB program on a computer. Then, the time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is calculated using the manual alignment method to verify the results and obtain the final time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve. Finally, the final time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is input into the MATLAB program to perform timing correction on the displacement signal, thereby obtaining the final measurement result.

[0012] Preferably, the manual alignment method is based on the comparison of peak values ​​or valley values ​​of the signals measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve, to find the time values ​​of the same peak value or valley value, and then calculate the time difference of the same peak value or valley value.

[0013] Preferably, in step S1, the multi-channel dynamic signal data acquisition system and the pressure scanning valve are respectively connected to the computer for communication, so that the signals measured by the single-channel piezoresistive differential pressure sensor, the pressure scanning valve and the laser displacement meter can be transmitted to the computer, and the computer has integrated pressure scanning valve acquisition system software interconnected with the pressure scanning valve.

[0014] Preferably, the multi-channel dynamic signal data acquisition system and the pressure scanning valve are respectively connected to the computer via network cables.

[0015] Preferably, in step S1, the interval between adjacent pressure measuring points set in areas where the pressure change on the model surface is large is smaller than the interval between adjacent pressure measuring points set in areas where the pressure change on the model surface is small.

[0016] Preferably, the external triggering system is a signal generator; In step S2, a specified signal emitted by the signal generator triggers the multi-channel dynamic signal data acquisition system and the pressure scanning valve to open synchronously for measurement. The specified signal is a square wave signal.

[0017] In a second aspect, the present invention provides a displacement and pneumatic pressure synchronous measurement system, including an external triggering system, a pressure scanning valve, a multi-channel dynamic signal data acquisition system, a single-channel piezoresistive differential pressure sensor, a laser displacement gauge, and a pressure measuring pipeline; The external triggering system is connected to the multi-channel dynamic signal data acquisition system and the pressure scanning valve via electrical signal lines; the multi-channel dynamic signal data acquisition system is connected to the single-channel piezoresistive differential pressure sensor and the laser displacement gauge via electrical signal lines. One end of the pressure measuring line is used to connect to the pressure measuring point on the model surface. One of the pressure measuring points is used as a reference pressure measuring point. The other end of the pressure measuring line connected to the reference pressure measuring point, a certain channel of the pressure scanning valve, and a single-channel piezoresistive differential pressure sensor are connected through a T-connector. The other end of the remaining pressure measuring lines is used to connect the remaining pressure measuring points to the corresponding channels in the remaining channels of the pressure scanning valve. The laser displacement meter is set at a position that can measure the displacement of the pressure measurement point. The laser displacement meter does not interfere with the movement of the structural segment model. The laser displacement meter is used to measure the displacement signal at the pressure measurement point. A single-channel piezoresistive differential pressure sensor is used to measure the pressure signal at a reference pressure point; The pressure scanning valve measures the pressure signal at all pressure measurement points, including the reference pressure measurement point.

[0018] Preferably, the external triggering system is a signal generator, which can emit a specified signal to trigger the multi-channel dynamic signal data acquisition system and the pressure scanning valve to open synchronously for measurement; The multi-channel dynamic signal data acquisition system and the pressure scanning valve are respectively connected to the computer for communication, so that the signals measured by the single-channel piezoresistive differential pressure sensor, the pressure scanning valve and the laser displacement meter can be transmitted to the computer. The computer has integrated pressure scanning valve acquisition system software that is interconnected with the pressure scanning valve.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a method for synchronously measuring displacement and pneumatic pressure. An external triggering system activates a multi-channel dynamic signal data acquisition system and a pressure scanning valve simultaneously for measurement. The pressure scanning valve and laser displacement gauge can synchronously measure the pressure and displacement at all measuring points. Although the hardware and software of the pressure scanning valve and laser displacement gauge systems are completely independent, and due to differences in construction and signal conversion principles, the time delays in signal acquisition, processing, and transmission between the laser displacement gauge and the pressure scanning valve differ, making direct synchronous signal acquisition difficult. However, by selecting a reference measuring point and connecting its measuring pipeline, a channel of the pressure scanning valve, and a single-channel piezoresistive differential pressure sensor via a three-way pipe, the pressure scanning valve and the single-channel piezoresistive differential pressure sensor can synchronously measure the pressure information at the same measuring point. To obtain more accurate basic signal reference data, the time difference between the pressure signals measured at the reference pressure point by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is calculated using the cross-correlation method and the manual alignment method. This method can accurately calculate the time difference between the measurement signals of the multi-channel dynamic signal data acquisition system and the pressure scanning valve. The time difference between the displacement and pneumatic pressure signals acquired by the laser displacement gauge and the single-channel piezoresistive differential pressure sensor is very small and can be ignored. Therefore, the time difference between the measurement signals of the multi-channel dynamic signal data acquisition system and the pressure scanning valve can be used to align the displacement signal measured by the laser displacement gauge with the pneumatic pressure signal measured by the pressure scanning valve in time series. This can significantly improve the consistency of signal timing, and the final result obtained by synchronous measurement is more accurate, providing more reliable data support for subsequent vibration analysis.

[0020] 2. This invention provides a synchronous measurement system for displacement and aerodynamic pressure. The final results obtained by synchronous measurement are more accurate, providing more reliable data support for subsequent vibration analysis. Attached Figure Description

[0021] Figure 1 A schematic diagram of the layout of a synchronous displacement and pneumatic pressure measurement system; Figure 2 This is a graph showing the time difference data analysis of the measurement signals from a multi-channel dynamic signal data acquisition system and a pressure scanning valve. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0023] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0024] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but that it can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0025] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0026] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as 2, 3, 4, 5, 6, 7, 8, or 9, and can even exceed nine.

[0027] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0028] Example 1 See Figure 1 A displacement and pneumatic pressure synchronous measurement system includes an external triggering system, a pressure scanning valve, a multi-channel dynamic signal data acquisition system, a single-channel piezoresistive differential pressure sensor, a laser displacement gauge, and a pressure measuring pipeline. The external triggering system is electrically connected to the multi-channel dynamic signal data acquisition system and the pressure scanning valve via electrical signal lines, such as optical fiber. Alternatively, the external triggering system can be a signal generator, which can send a specified signal to trigger the multi-channel dynamic signal data acquisition system and the pressure scanning valve to synchronously begin measurement. Because the signal generator directly sends the specified signal to the multi-channel dynamic signal data acquisition system and the pressure scanning valve without any intermediaries, the time difference in starting measurement is smaller, resulting in all measurements being more closely aligned under the same conditions and timeframe, leading to more accurate measurement results. The specified signal can be a square wave signal, primarily informing the multi-channel dynamic signal data acquisition system and the pressure scanning valve to begin measurement. The multi-channel dynamic signal data acquisition system is connected to the single-channel piezoresistive differential pressure sensor and the laser displacement meter via electrical signal lines, which can be optical fibers. The multi-channel dynamic signal data acquisition system can control the single-channel piezoresistive differential pressure sensor and the laser displacement meter to perform measurements simultaneously. The time difference between the two signals is very small and can be ignored. The pressure measuring line connects the pressure measuring points and the sensor channels. Several pressure measuring points are set on the surface of the structural segment model. These points can be achieved by creating holes in the surface of the structural segment model, which must penetrate the structural surface to install the pressure measuring line and allow gas to enter the line for pneumatic pressure measurement. A specific pressure measuring point is selected as a reference point. Its pressure measuring line, a channel of the pressure scanning valve, and a single-channel piezoresistive differential pressure sensor are connected via a T-junction. Other pressure measuring points and other channels of the pressure scanning valve correspond one-to-one and are connected via other pressure measuring lines, enabling the pressure scanning valve to measure the gas pressure at each measuring point. The dynamic pressure signal is detected, while the single-channel piezoresistive differential pressure sensor only detects the pneumatic pressure signal at one pressure measurement point (reference point). Since both the single-channel piezoresistive differential pressure sensor and the pressure scanning valve detect the pneumatic pressure at one pressure measurement point (reference point), the measurement at that pressure measurement point is based on the same basis for both and can be used as a reference to judge the time difference between the two measurement signals. This situation based on the same pressure measurement point can simulate the exact same measurement conditions, so it can more accurately reflect the time difference between the single-channel piezoresistive differential pressure sensor and the pressure scanning valve under the same conditions in the same time period. The laser displacement gauge is set at a position that can measure the displacement of the pressure measurement point. The laser displacement gauge does not interfere with the movement of the structural segment model, thus avoiding affecting the movement of the structural segment model. The movement of the structural segment model can be free movement under the action of wind, or forced movement driven by mechanical structures, etc. The laser displacement gauge is used to measure the displacement signal at the pressure measurement point.

[0029] The displacement and pneumatic pressure synchronous measurement system described in this embodiment enables the pressure scanning valve, single-channel piezoresistive differential pressure sensor, and laser displacement gauge to measure under similar conditions and within the same time period. Furthermore, the pressure scanning valve and single-channel piezoresistive differential pressure sensor can measure the same pressure point as a reference for the time difference between the pressure scanning valve measuring the pneumatic pressure at all pressure points and the displacement gauge measuring the displacement at all pressure points. This allows the pneumatic pressure and displacement to be synchronized, ensuring more accurate final measurement results.

[0030] In an optional implementation, the multi-channel dynamic signal data acquisition system and the pressure scanning valve are respectively connected to a computer via communication, such as by fiber optic connection or wireless communication connection, so that the signals measured by the single-channel piezoresistive differential pressure sensor, the pressure scanning valve and the laser displacement gauge can all be transmitted to the computer. The computer integrates pressure scanning valve acquisition system software that is interconnected with the pressure scanning valve, and can display the measurement signals and calculate the time difference through the computer.

[0031] Example 2 A method for simultaneous measurement of displacement and aerodynamic pressure includes the following steps: S1. Connect the external triggering system to the multi-channel dynamic signal data acquisition system and the pressure scanning valve respectively via electrical signal lines; connect the multi-channel dynamic signal data acquisition system to the single-channel piezoresistive differential pressure sensor and the laser displacement gauge respectively via electrical signal lines; Several pressure measurement points are set at the locations on the model surface where pressure measurement is required, and a pressure measurement pipeline is installed at each pressure measurement point. The pressure measurement pipeline can be a PVC flexible tube with an outer diameter of 2mm and an inner diameter of 1mm or other capillary tube. In an optional embodiment, in step S1, the interval between adjacent pressure measurement points set in areas with large pressure changes on the model surface is smaller than the interval between adjacent pressure measurement points set in areas with small pressure changes on the model surface; a certain pressure measurement point is selected as a reference point, and its pressure measurement pipeline, a certain channel of the pressure scanning valve, and a single-channel piezoresistive differential pressure sensor are connected through a T-junction. Other pressure measurement points and other channels of the pressure scanning valve correspond one-to-one and are connected through pressure measurement pipelines; and a laser displacement gauge is set at a position that can measure the displacement of the pressure measurement point. The laser displacement gauge does not interfere with the movement of the structural segment model, such as the two not being in contact. In step S1, the multi-channel dynamic signal data acquisition system and the pressure scanning valve are respectively connected to the computer for communication, so that the signals measured by the single-channel piezoresistive differential pressure sensor, the pressure scanning valve and the laser displacement meter can be transmitted to the computer. In an optional embodiment, the multi-channel dynamic signal data acquisition system and the pressure scanning valve are respectively connected to the computer via network cable, and the computer integrates the pressure scanning valve acquisition system software interconnected with the pressure scanning valve.

[0032] S2. The multi-channel dynamic signal data acquisition system and the pressure scanning valve are simultaneously activated for measurement via an external triggering system. In an optional implementation, the external triggering system is a signal generator; in step S2, the multi-channel dynamic signal data acquisition system and the pressure scanning valve are triggered to open synchronously for measurement by a specified signal emitted by the signal generator, and the specified signal is a square wave signal.

[0033] S3, the multi-channel dynamic signal data acquisition system measures the displacement of the pressure measurement points of the structural segment model through a laser displacement meter and simultaneously measures the pressure signal of the reference pressure measurement point through a single-channel piezoresistive differential pressure sensor; Simultaneously, the pressure scanning valve measures the pressure signals of all pressure measurement points on the surface of the model, including the reference pressure measurement point; the measured pressure signals are displacement signals that are ultimately formed into an image. The horizontal axis of the image formed by the pressure signals is time, and the vertical axis is pressure; the horizontal axis of the image formed by the displacement signals is time, and the vertical axis is displacement. S4. The time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is calculated based on two methods: cross-correlation method and manual alignment method. Then, the displacement signal is time-corrected according to the time difference to obtain the final measurement result.

[0034] Preferably, in step S4, the time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is first calculated by a computer based on the cross-correlation method; in an optional embodiment, the time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is calculated by a MATLAB program on a computer based on the cross-correlation method. Then, the time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is calculated by manual alignment method to achieve verification and obtain the final time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve. In an optional embodiment, the manual alignment method is based on the comparison of peak values ​​or valley values ​​of the signals measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve to find the time values ​​of the same peak value or valley value, and then calculate the time difference of the same peak value or valley value.

[0035] Then, the displacement signal is corrected for timing based on the time difference to obtain the final measurement result.

[0036] This embodiment describes a method for synchronously measuring displacement and pneumatic pressure. An external triggering system activates a multi-channel dynamic signal data acquisition system and a pressure scanning valve simultaneously. The pressure scanning valve and laser displacement gauge can synchronously measure the pressure and displacement at all measuring points. Although the hardware and software of the pressure scanning valve and laser displacement gauge systems are completely independent, and due to differences in construction and signal conversion principles, the time delays in signal acquisition, processing, and transmission between the laser displacement gauge and the pressure scanning valve differ, making direct synchronous signal acquisition difficult. However, by selecting a reference measuring point and connecting its measuring pipeline, a channel of the pressure scanning valve, and a single-channel piezoresistive differential pressure sensor via a three-way connector, the pressure scanning valve and the single-channel piezoresistive differential pressure sensor can be simultaneously measured. Differential pressure sensors can synchronously measure pressure information at the same pressure measurement point, serving as relatively accurate basic signal reference data. By using cross-correlation and manual alignment methods to calculate the time difference between the pressure signals measured at the reference pressure measurement point by a single-channel piezoresistive differential pressure sensor and a pressure scanning valve, the time difference between the measurement signals of the multi-channel dynamic signal data acquisition system and the pressure scanning valve can be accurately calculated. Since the time difference between the displacement and pneumatic pressure signals acquired by the laser displacement gauge and the single-channel piezoresistive differential pressure sensor is very small and can be ignored, the time difference between the measurement signals of the multi-channel dynamic signal data acquisition system and the pressure scanning valve can be used to align the displacement signal measured by the laser displacement gauge with the pneumatic pressure signal measured by the pressure scanning valve. Figure 2 As shown, this can significantly improve the consistency of signal timing, and the final results obtained by synchronous measurement are more accurate, providing more reliable data support for subsequent vibration analysis.

[0037] Experiments have shown that by combining a single-channel piezoresistive differential pressure sensor with cross-correlation and manual alignment methods, and by using a signal generator to directly send signals to the multi-channel dynamic signal data acquisition system and pressure scanning valve for measurement, the displacement and pneumatic pressure synchronous measurement method in this embodiment achieves higher accuracy than other calibrators and manual selection methods, resulting in data that is closer to the actual situation.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for simultaneous measurement of displacement and aerodynamic pressure, characterized in that, Includes the following steps: S1. Connect the external triggering system to the multi-channel dynamic signal data acquisition system and the pressure scanning valve respectively via electrical signal lines; connect the multi-channel dynamic signal data acquisition system to the single-channel piezoresistive differential pressure sensor and the laser displacement gauge respectively via electrical signal lines; Several pressure measurement points are arranged on the surface of the structural segment model, and a pressure measurement pipeline is installed at each pressure measurement point. One pressure measurement point is selected as a reference pressure measurement point. One end of the pressure measurement pipeline of the reference pressure measurement point is connected to the end of the pressure measurement pipeline through a tee pipe, and the other two ends are respectively connected to a certain channel of the pressure scanning valve and a single-channel piezoresistive differential pressure sensor. The remaining pressure measurement pipelines are connected to the pressure measurement points and one of the remaining channels of the pressure scanning valve. The laser displacement gauge is set at a position that can measure the displacement of the pressure measurement point, and the laser displacement gauge does not interfere with the movement of the structural segment model; S2. The multi-channel dynamic signal data acquisition system and the pressure scanning valve are simultaneously activated for measurement via an external triggering system. S3, the multi-channel dynamic signal data acquisition system measures the displacement of the pressure measurement points of the structural segment model through a laser displacement meter and simultaneously measures the pressure signal of the reference pressure measurement point through a single-channel piezoresistive differential pressure sensor; At the same time, the pressure scanning valve measures the pressure signals of all pressure measurement points arranged on the surface of the model; S4. The time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is calculated based on two methods: cross-correlation method and manual alignment method. Then, the displacement signal is time-corrected according to the time difference to obtain the final measurement result. In step S4, the time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is first calculated by computer using the cross-correlation method. Then, the time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve is calculated by manual alignment method to achieve verification and obtain the final time difference between the signals of the reference pressure measurement point measured by the single-channel piezoresistive differential pressure sensor and the pressure scanning valve. Finally, the displacement signal is time-corrected according to the time difference to obtain the final measurement result.

2. The method for synchronous measurement of displacement and pneumatic pressure according to claim 1, characterized in that, The time difference between the signals measured by a single-channel piezoresistive differential pressure sensor and the reference pressure measurement point measured by the pressure scanning valve is calculated using a MATLAB program based on the cross-correlation method. Then, the time difference between the signals is calculated again using a manual alignment method to verify the results and obtain the final time difference between the signals measured by the single-channel piezoresistive differential pressure sensor and the reference pressure measurement point measured by the pressure scanning valve. Finally, the final time difference between the signals measured by the single-channel piezoresistive differential pressure sensor and the reference pressure measurement point measured by the pressure scanning valve is input into the MATLAB program to perform timing correction on the displacement signal, thus obtaining the final measurement result.

3. The method for synchronous measurement of displacement and pneumatic pressure according to claim 2, characterized in that, The manual alignment method is based on the comparison of peak values ​​or valley values ​​of the signals measured by a single-channel piezoresistive differential pressure sensor and a pressure scanning valve, to find the time values ​​of the same peak value or valley value, and then calculate the time difference of the same peak value or valley value.

4. The method for synchronous measurement of displacement and pneumatic pressure according to claim 1, characterized in that, In step S1, the multi-channel dynamic signal data acquisition system and the pressure scanning valve are respectively connected to the computer for communication, so that the signals measured by the single-channel piezoresistive differential pressure sensor, the pressure scanning valve and the laser displacement meter can be transmitted to the computer, and the computer has integrated pressure scanning valve acquisition system software that is interconnected with the pressure scanning valve.

5. The method for synchronous measurement of displacement and pneumatic pressure according to claim 4, characterized in that, The multi-channel dynamic signal data acquisition system and the pressure scanning valve are connected to the computer via network cables.

6. A method for synchronously measuring displacement and pneumatic pressure according to any one of claims 1-5, characterized in that, In step S1, the interval between adjacent pressure measuring points set in areas with large pressure changes on the model surface is smaller than the interval between adjacent pressure measuring points set in areas with small pressure changes on the model surface.

7. A method for synchronously measuring displacement and pneumatic pressure according to any one of claims 1-5, characterized in that, The external triggering system is a signal generator; In step S2, a specified signal emitted by the signal generator triggers the multi-channel dynamic signal data acquisition system and the pressure scanning valve to open synchronously for measurement. The specified signal is a square wave signal.

8. A system for synchronously measuring displacement and pneumatic pressure, characterized in that, Includes an external triggering system, a pressure scanning valve, a multi-channel dynamic signal data acquisition system, a single-channel piezoresistive differential pressure sensor, a laser displacement gauge, and pressure measurement pipelines; The external triggering system is connected to the multi-channel dynamic signal data acquisition system and the pressure scanning valve via electrical signal lines; the multi-channel dynamic signal data acquisition system is connected to the single-channel piezoresistive differential pressure sensor and the laser displacement gauge via electrical signal lines. One end of the pressure measuring line is used to connect to the pressure measuring point on the model surface. One of the pressure measuring points is used as a reference pressure measuring point. The other end of the pressure measuring line connected to the reference pressure measuring point, a certain channel of the pressure scanning valve, and a single-channel piezoresistive differential pressure sensor are connected through a T-connector. The other end of the remaining pressure measuring lines is used to connect the remaining pressure measuring points to the corresponding channels in the remaining channels of the pressure scanning valve. The laser displacement meter is set at a position that can measure the displacement of the pressure measurement point. The laser displacement meter does not interfere with the movement of the structural segment model. The laser displacement meter is used to measure the displacement signal at the pressure measurement point. A single-channel piezoresistive differential pressure sensor is used to measure the pressure signal at a reference pressure point; The pressure scanning valve measures the pressure signal at all pressure measurement points, including the reference pressure measurement point.

9. The displacement and pneumatic pressure synchronous measurement system according to claim 8, characterized in that, The external triggering system is a signal generator, which can send a specified signal to trigger the multi-channel dynamic signal data acquisition system and the pressure scanning valve to open synchronously for measurement. The specified signal is a square wave signal. The multi-channel dynamic signal data acquisition system and the pressure scanning valve are respectively connected to the computer for communication, so that the signals measured by the single-channel piezoresistive differential pressure sensor, the pressure scanning valve and the laser displacement meter can be transmitted to the computer. The computer has integrated pressure scanning valve acquisition system software that is interconnected with the pressure scanning valve.

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