System and method for measuring delay time of micro-pressure pipeline

Abstract

The present invention provides a system and method for measuring the delay time of a micro-pressure pipeline. The system includes a vacuum environment simulator, a pressure signal generator and a control device, and a FADS pressure measurement pipeline, an acquisition system, and a processing system. The vacuum environment simulator is used to simulate ambient pressures at different flight altitudes. The pressure signal generator is placed within the vacuum environment simulator and, under the control of the control device, produces dynamic pressure signals of various amplitudes and frequencies. The FADS pressure measurement pipeline includes a main pipeline connected to the aircraft surface, a first branch connected to the main pipeline and connected to an absolute pressure sensor, and a second branch connected to a differential pressure sensor. The acquisition system is communicatively connected to the absolute pressure sensor and the differential pressure sensor. In this embodiment, the processing system determines the Mach number based on the first branch and selects a corresponding branch based on the Mach number range to determine the delay time.

Description

Technical Field

[0001] The present invention relates to the field of atmospheric data sensing technology, and in particular to a system and method for measuring the delay time of a micro-pressure pipeline. Background Art

[0002] The Flush Air Data Sensing (FADS) system relies on an array of pressure sensors to measure the pressure distribution on the aircraft surface. Using specific algorithms, it indirectly obtains flight atmospheric data such as static pressure, Mach number, angle of attack, and sideslip angle. The FADS system is the primary means for aircraft to obtain flight atmospheric data as flight control input, and is particularly important for hypersonic aircraft.

[0003] The FADS system primarily consists of pressure-inducing piping and high-precision pressure sensors. Pneumatic piping connects the pressure sensors to the surface of the aircraft. These piping transmits surface pressure signals to the pressure sensors, thereby obtaining surface pressure parameters. The length, diameter, and volume of each sensor cavity in the pneumatic piping affect the sensor's frequency characteristics. The pneumatic capillary connecting the sensor to the surface acts as a low-pass filter. Improper design of the capillary length, diameter, and sensor cavity volume, resulting in excessive or insufficient damping, can lead to excessive attenuation of high-frequency amplitudes or unstable frequency responses, potentially causing sensor malfunction. Therefore, analyzing the dynamic characteristics of the pneumatic piping system and selecting the appropriate capillary diameter, length, and sensor cavity volume are crucial for the optimal design of pressure sensors. Summary of the Invention

[0004] The content of this disclosure is intended to briefly introduce concepts that will be described in detail in the detailed description below. The content of this disclosure is not intended to identify key features or essential features of the claimed technical solution, nor is it intended to limit the scope of the claimed technical solution.

[0005] Some embodiments of the present invention provide a system and method for measuring the delay time of a micro-pressure pipeline to solve the technical problems mentioned in the above background technology section.

[0006] In a first aspect, some embodiments of the present invention provide a system for measuring the delay time of a micro-pressure pipeline, the system comprising a vacuum environment simulation device, a pressure signal generating device and a control device connected in communication, and a FADS pressure measuring pipeline, an acquisition system, and a processing system connected in communication in sequence, wherein:

[0007] The vacuum environment simulation device is used to simulate the environmental pressure at different flight altitudes;

[0008] The pressure signal generating device is placed in the vacuum environment simulation device and generates dynamic pressure signals of various amplitudes and frequencies under the control of the control device;

[0009] The FADS pressure measuring pipeline includes a main pipeline connected to the surface of the aircraft, a first branch connected to an absolute pressure sensor and a second branch connected to a differential pressure sensor, both of which are connected to the main pipeline;

[0010] The acquisition system is communicatively connected with the absolute pressure sensor and the differential pressure sensor;

[0011] The processing system determines the Mach number according to the first branch, selects the corresponding branch according to the range of the Mach number, and determines the delay time.

[0012] In a second aspect, some embodiments of the present invention provide a method for measuring a micro-pressure pipeline delay time according to any embodiment of the first aspect, including:

[0013] The vacuum environment simulation device simulates the environmental pressure at the target flight altitude;

[0014] The control device controls the pressure signal generating device to generate a corresponding dynamic pressure signal;

[0015] The acquisition system collects data from absolute pressure sensors and differential pressure sensors;

[0016] The Mach number is determined based on the first branch; if the Mach number exceeds 0.2, a delay time is determined based on the first branch; if the Mach number is less than 0.2, a delay time is determined based on the second branch.

[0017] The above embodiments of the present invention have the following beneficial effects:

[0018] The vacuum environment simulator can simulate ambient pressures at different flight altitudes, providing a variety of simulation scenarios. Under the control of the control device, the pressure signal generator can produce dynamic pressure signals of various amplitudes and frequencies, providing experimental conditions for measurement. The configuration of the first and second branches allows for measurements across a wide range of Mach numbers, improving the measurement system's specificity and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1Schematic diagram of the structure of an embodiment of a system for measuring delay time of a micro-pressure pipeline of the present invention;

[0021] Figure 2 Schematic diagram of the structure of an embodiment of a pressure signal generating device of the present invention;

[0022] Figure 3 The analog waveform of the periodic pressure signal of the pressure signal generating device of the present invention;

[0023] Figure 4 This is the delay measurement result of the 250mm length pipeline of the present invention;

[0024] Figure 5 This is the delay measurement result of the 620 mm long pipeline of the present invention.

[0025] Description of reference numerals:

[0026] 11. Vacuum barrel; 12. Vacuum pump;

[0027] 2. Pressure signal generating device; 21. Motor; 22. Base; 221. Fixed plate; 23. Turntable; 24. Pivot shaft; 25. First connecting rod; 26. Second connecting rod; 27. Linear bearing; 28. Coupling; 29. ​​Cylinder;

[0028] 311, first branch; 312, absolute pressure sensor; 321, second branch; 322, differential pressure sensor; 323, solenoid valve;

[0029] 4. Collection system;

[0030] 5. Processing system. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0034] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0035] First see Figure 1 , Figure 1 FIG. 1 is a schematic structural diagram of an embodiment of a system for measuring the delay time of a micro-pressure pipeline according to the present invention. Figure 1 As shown, the micro-pressure pipeline delay time measurement system includes a vacuum environment simulation device, a pressure signal generating device 2 and a control device that are communicatively connected, and a FADS pressure measuring pipeline, an acquisition system 4 and a processing system 5 that are communicatively connected in sequence.

[0036] The vacuum environment simulation device includes a vacuum barrel 11 and a vacuum pump 12 connected to the vacuum barrel 11. The vacuum barrel 11 is equipped with a precision digital absolute pressure gauge or a thin film vacuum gauge, etc., with an accuracy level of 0.05% FS and a range of 0 to 101.3 kPa. During the measurement process, the aircraft model is placed in the vacuum barrel 11. By controlling the vacuum pump 12, the ambient pressure value in the vacuum barrel 11 can be adjusted to simulate the flight altitude. For example, an ambient pressure of 10 Pa is equivalent to simulating a flight airspace at an altitude of 65 km according to the standard atmospheric model. Those skilled in the art can select matching specifications and quantities of vacuum pumps 12 based on actual conditions and design requirements.

[0037] See also Figure 2 , Figure 2 FIG. 1 is a schematic structural diagram of an embodiment of a pressure signal generating device of the present invention. Figure 2As shown, the dynamic pressure signal generating device 2 comprises a motor 21, a reciprocating mechanism, a cylinder 29, and a base 22. A fixed plate 221 is also provided on the base 22. The motor 21 is fixed to one side of the fixed plate 221. The drive shaft of the motor 21 passes through the fixed plate 221 and is connected to the reciprocating mechanism. The reciprocating mechanism includes a turntable 23 connected to the drive shaft of the motor 21. A pivot shaft 24 is fixed at an eccentric position on the turntable 23. A first connecting rod 25 is rotatably mounted on the pivot shaft 24. The other end of the first connecting rod 25 is pivotally connected to a second connecting rod 26. The second connecting rod 26 is connected to the telescopic end of the cylinder 29 via a coupling 28.

[0038] Furthermore, in order to limit the movement direction of the second connecting rod 26 , a linear bearing 27 is fixed on the fixing plate 221 , and the second connecting rod 26 can slidably pass through the linear bearing 27 .

[0039] The control device can be in communication with the dynamic pressure signal generating device 2, and the motor 21 of the dynamic pressure signal generating device 2 can be controlled by the control device. As an example, the control device can be a central processing unit, a microprocessor, etc.

[0040] During the measurement process, the dynamic pressure signal generating device 2 is placed in the vacuum chamber 11. The control device controls the motor 21 to operate, thereby driving the turntable 23 and the pivot shaft 24 to rotate, so that the first connecting rod 25 acts on the second connecting rod 26. The second connecting rod 26 can drive the telescopic end of the cylinder 29 to reciprocate along the linear axis, so that the cylinder 29 outputs airflow and blows it towards the aircraft model, simulating a periodic pressure signal with a frequency of 3.3 Hz to 7.6 Hz. Thus, dynamic pressure signals of various amplitudes and frequencies are generated. See for details. Figure 3 , Figure 3 This is the simulated waveform of the periodic pressure signal of the pressure signal generating device of the present invention.

[0041] The surface of the aircraft model is provided with a plurality of openings, each of which may have a diameter of 1 mm. There may be nine openings, defined as P1 to P9. Each opening is connected to the main pipe of the FADS pressure measuring line, which is divided into a first branch 311 and a second branch 321 by a tee. The first branch 311 may be directly connected to the absolute pressure sensor 312, and the second branch 321 is connected to the electromagnetic valve 323 and then to the differential pressure sensor 322. The absolute pressure sensor 312 may have a measuring range of ±20 PSI (±137,900 Pa) with an accuracy of 0.04% (55 Pa). The differential pressure sensor 322 may have a measuring range of ±1 PSI (±6,895 Pa) with an accuracy of 0.1% (7 Pa).

[0042] Figure 4 This is the delay measurement result of the 250mm length pipeline of the present invention; Figure 5This is the delay measurement result of the 620mm length pipeline of the present invention. Figure 4 and Figure 5 As shown, the FADS pressure measuring line can be set to different diameters or lengths for comparative measurements.

[0043] The absolute pressure sensor 312 is packaged in a "single-pipe" housing, while the differential pressure sensor 322 is packaged in a "double-pipe" housing. The housing dimensions are 38.1mm x 38.1mm x 43.18mm, and the output pipe has an inner diameter of 1mm and an outer diameter of 2mm.

[0044] The acquisition system 4 is communicatively connected to the absolute pressure sensor 312 and differential pressure sensor 322. For example, the acquisition system 4 can be a USB5630 acquisition card, which provides 32-channel differential input acquisition. The analog input section of the USB5630 primarily consists of an analog-to-digital (A / D) analog input port, an input selection module, a programmable amplifier, a low-pass filter, an A / D converter, an A / D buffer, and a trigger. The acquisition card has a 16-bit resolution and a maximum sampling rate of 500 kSPS.

[0045] During the measurement process, the acquisition system 4 records the real-time relationship between the output of the absolute pressure sensor 312 and the differential pressure sensor 322 and the input pressure, and evaluates their dynamic characteristics by analyzing their time and frequency domain responses. It can also calculate the dynamic response error and delay time by comparing the actual output with the ideal output.

[0046] The FADS solution algorithm based on BP neural network technology and CFD technology is established. The aircraft surface pressure data measured by the absolute pressure sensor 312 of the first branch 311 is used to solve the flight flow Mach number and determine the range of the Mach number Ma.

[0047] The processing system 5 may be a DSP (Digital Signal Processing) and an FPGA (Field Programmable Gate Array) working in coordination.

[0048] If Ma>0.2, the solenoid valve 323 of the second branch 321 is closed, and the DSP uses the aircraft surface pressure data measured by the absolute pressure sensor 312 of the first branch 311. The pressure data is solved by the FADS algorithm to obtain flight flow parameters such as Mach number, static pressure, angle of attack and sideslip angle, and the data is returned to the FPGA. The flight flow parameter measurement results are output through RS422.

[0049] If Ma ≤ 0.2, the solenoid valve 323 of the second branch 321 opens. The DSP uses the drone's surface pressure data measured by the differential pressure sensor 322 of the second branch 321. The vertex is still measured by the absolute pressure sensor 312, while the other points P2 to P9 are measured by differential pressure sensors 322. The pressure at vertex P1 is used as a reference. The pressure differentials at points P2 to P9 are measured and added to the vertex P1 to obtain the absolute pressure at each point. This method achieves high pressure accuracy and is very useful for low-Mach number pressure measurement. The pressure data is solved using the FADS algorithm to obtain flight flow parameters such as Mach number, static pressure, angle of attack, and sideslip angle. This data is returned to the FPGA, and the flight flow parameter measurement results are output via RS422.

[0050] That is to say, the absolute pressure sensor 312 and the differential pressure sensor 322 adopt different ranges and accuracies and can adapt to different Mach number ranges.

[0051] The measurement range of the measurement system is 8 to 13 for Mach number, 60 to 85 km for static altitude, and -15 to 15 degrees for angle of attack and sideslip angle.

[0052] After repeated verification, the measurement errors (3σ) of the measurement system are: Mach number error ≤ 0.01, static pressure error ≤ 100Pa, angle of attack error ≤ 1.5° (Ma<0.1) / ≤ 0.5° (Ma≥0.1) and sideslip angle error ≤ 1.8° (Ma<0.1) / ≤ 0.5° (Ma≥0.1).

[0053] Finally, when correcting the above delay time, the system can be considered as a linear, time-invariant system, and its characteristics can be described by the transfer function. First, considering the processing of digital signals, it is more convenient to describe the discrete system transfer function in the Z transform domain. Therefore, the discrete system transfer function model is first used to identify the dynamic characteristics of the probe. The m-order linear discrete system transfer function is

[0054]

[0055] Among them, U(z) and Y(z) are the true value (pressure not transmitted through the pipeline) and the measured value (pressure after transmission through the pipeline), respectively; m represents the order, which can be determined by those skilled in the art through experiments or common sense; a1···am and b0··bm are unknown parameters determined by fitting, and d is the hysteresis, which can be determined by those skilled in the art through experiments or common sense.

[0056] U(z) and Y(z) are the Z-transforms of the input and output signals, respectively. The time delay Td between the input and output signals is a constant to be determined, and the corresponding number of sampling points is d = fs·Td. Therefore, this method requires the use of differential equations of an m-order discrete system model to identify the unknown parameters a1···am and b0··bm.

[0057] This system uses dual sets of absolute and differential pressure sensors, combined with the FADS algorithm to control a solenoid valve to select the sensor set based on the Mach number range to measure the surface pressure of the drone. This effectively solves the problem of measuring atmospheric data in both low and high Mach number ranges. The system boasts high accuracy, simple structure, and low cost.

[0058] The present invention can be used in the Mach number range of 8 to 13, can meet most of the hypersonic flight speed range, and has high measurement accuracy in both the low Mach number segment and the high Mach number segment.

[0059] The absolute pressure sensor of the present invention adopts a "single-pipe" box packaging form, while the differential pressure sensor adopts a "double-pipe" box packaging form. After packaging, the volume is small and the structure is strong.

[0060] The present invention also provides a method for measuring the delay time of a micro-pressure pipeline, which can be used in the micro-pressure pipeline delay time measurement system in each of the above embodiments. The method specifically includes:

[0061] The vacuum environment simulation device simulates the environmental pressure at the target flight altitude;

[0062] The control device controls the pressure signal generating device to generate a corresponding dynamic pressure signal;

[0063] The acquisition system collects data from absolute pressure sensors and differential pressure sensors;

[0064] The Mach number is determined based on the first branch; if the Mach number exceeds 0.2, a delay time is determined based on the first branch; if the Mach number is less than 0.2, a delay time is determined based on the second branch.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for measuring delay time of a micro-pressure pipeline, characterized in that: It includes a vacuum environment simulation device, a pressure signal generating device and a control device connected in communication, and a FADS pressure measuring pipeline, an acquisition system and a processing system connected in communication in sequence, wherein: The vacuum environment simulation device is used to simulate the environmental pressure at different flight altitudes; The pressure signal generating device is placed in the vacuum environment simulation device and generates dynamic pressure signals of various amplitudes and frequencies under the control of the control device; The FADS pressure measuring pipeline includes a main pipeline connected to the surface of the aircraft, a first branch connected to an absolute pressure sensor and a second branch connected to a differential pressure sensor, both of which are connected to the main pipeline; The acquisition system is communicatively connected with the absolute pressure sensor and the differential pressure sensor; The processing system determines the Mach number according to the first branch, selects the corresponding branch according to the range of the Mach number, and determines the delay time.

2. The system for measuring the delay time of a micro-pressure pipeline according to claim 1, characterized in that: The vacuum environment simulation device includes a vacuum barrel, a vacuum pump connected to the vacuum barrel, and a precision digital absolute pressure gauge arranged in the vacuum barrel.

3. The system for measuring the delay time of a micro-pressure pipeline according to claim 2, characterized in that: The precision digital absolute pressure gauge has an accuracy grade of 0.05% FS and a measuring range of 0 to 101.3 kPa.

4. The system for measuring the delay time of a micro-pressure pipeline according to claim 1, characterized in that: The dynamic pressure signal generating device includes a motor, a reciprocating mechanism and a cylinder which are sequentially connected to the control device for communication. The motor is used to drive the reciprocating mechanism to drive the cylinder to extend and retract.

5. The system for measuring the delay time of a micro-pressure pipeline according to claim 4, characterized in that: The reciprocating mechanism includes a turntable connected to the motor, a pivot shaft is fixed at an eccentric position of the turntable, a first connecting rod is rotatably mounted on the pivot shaft, the other end of the first connecting rod is pivotally connected to the second connecting rod, and the second connecting rod is connected to the telescopic end of the cylinder.

6. The system for measuring the delay time of a micro-pressure pipeline according to claim 5, characterized in that: The second connecting rod is connected to the telescopic end of the cylinder through a coupling.

7. The system for measuring the delay time of a micro-pressure pipeline according to claim 6, characterized in that: The dynamic pressure signal generating device further comprises a base, a fixing plate is provided at the upper end of the base, and the motor is fixed to the fixing plate; a linear bearing is fixed on the fixing plate, and the second connecting rod can slidably pass through the linear bearing.

8. The system for measuring delay time of a micro-pressure pipeline according to claim 1, characterized in that: The measuring range of the absolute pressure sensor is ±20PSI (±137900Pa) with an accuracy of 0.04% (55Pa); the measuring range of the differential pressure sensor is ±1PSI (±6895Pa) with an accuracy of 0.1% (7Pa).

9. The system for measuring delay time of a micro-pressure pipeline according to claim 1, characterized in that: The second branch is provided with an electromagnetic valve.

10. A method for use in a system for measuring delay time of a micro-pressure pipeline according to any one of claims 1 to 9, the method comprising: The vacuum environment simulation device simulates the environmental pressure at the target flight altitude; The control device controls the pressure signal generating device to generate a corresponding dynamic pressure signal; The acquisition system collects data from absolute pressure sensors and differential pressure sensors; The Mach number is determined based on the first branch; if the Mach number exceeds 0.2, a delay time is determined based on the first branch; if the Mach number is less than 0.2, a delay time is determined based on the second branch.

Images