Measuring system for delay time of micro-pressure pipeline

Abstract

The utility model provides a system for measuring delay time of a micro-pressure pipeline, which comprises a vacuum environment simulation device, a pressure signal generating device and a control device which are in communication connection, and an FADS pressure measuring pipeline, an acquisition system and a processing system which are in communication connection in sequence, and is characterized in that the vacuum environment simulation device is used for simulating environment pressure at different flight heights; the pressure signal generation device is placed in the vacuum environment simulation device and is used for generating dynamic pressure signals with various amplitudes and frequencies under the control of the control device; the FADS pressure measuring pipeline comprises a main pipeline communicated to the surface of an aircraft, a first branch connected with an absolute pressure sensor and a second branch connected with a differential pressure sensor, wherein the first branch and the second branch are communicated with the main pipeline. And the acquisition system is in communication connection with the absolute pressure sensor and the differential pressure sensor. According to the embodiment, 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.

Description

TECHNICAL FIELD

[0001] The utility model relates to atmospheric data sensing technical field especially is related to a micro pressure pipeline delay time's measurement system. BACKGROUND

[0002] Flush Air Data Sensing (FADS) system measures the pressure distribution of the surface of the aircraft by means of a pressure sensor array, and indirectly obtains flight atmospheric data such as static pressure, Mach number, angle of attack, and sideslip angle by means of a specific algorithm. The FADS system is the main way for the aircraft to obtain flight atmospheric data as flight control input, and is particularly important for hypersonic aircraft.

[0003] The FADS system mainly consists of a pilot pressure pipeline and a high-precision pressure sensor. The pressure sensor is connected to the surface of the aircraft by a pneumatic pipeline, and the pressure signal of the surface is transmitted to the pressure sensor by the pipeline, so as to obtain the surface pressure parameters of the aircraft. The length, diameter, and volume of the sensor cavity of the pneumatic pipeline will affect the frequency characteristics of the sensor. The pneumatic fine tube connecting the sensor and the surface is equivalent to a low-pass filter. If the length, diameter, and sensor cavity volume of the fine tube are not properly designed, the damping will be too large or too small, which will cause excessive amplitude attenuation or unstable frequency response in the high-frequency band, and these will cause the sensor to work abnormally. Therefore, analyzing the dynamic characteristics of the pneumatic pipeline system and selecting appropriate fine tube diameter, length, and sensor cavity volume are helpful for the reasonable design of the pressure sensor. SUMMARY

[0004] The content part of the utility model is used to briefly introduce the concept, which will be described in detail in the specific embodiment part. The content part of the disclosure is not intended to identify the 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 utility model provide a micro pressure pipeline delay time measurement system to solve the technical problems mentioned in the background technology part.

[0006] Some embodiments of the utility model provide a micro pressure pipeline delay time measurement system, which comprises a vacuum environment simulation device, a pressure signal generation device and a control device connected in communication, and a FADS pressure measuring pipeline, a collection system, and a processing system connected in communication.

[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 into the vacuum environment simulation device, and under the control of the control device, a dynamic pressure signal with various amplitudes and frequencies is generated.

[0009] The FADS pressure measuring pipeline comprises a main pipeline communicated to the surface of the aircraft, and a first branch connected with an absolute pressure sensor and a second branch connected with a differential pressure sensor communicated to the main pipeline.

[0010] The acquisition system is in communication connection with the absolute pressure sensor and the differential pressure sensor.

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

[0012] Optionally, the vacuum environment simulation device comprises a vacuum barrel, a vacuum pump communicated to the vacuum barrel, and a precision digital absolute pressure gauge arranged in the vacuum barrel.

[0013] Optionally, the precision digital absolute pressure gauge has an accuracy level of 0.05% F.S and a range of 0-101.3 kPa.

[0014] Optionally, the dynamic pressure signal generating device comprises a motor, a reciprocating mechanism and a cylinder connected in sequence and in communication connection with the control device, and the motor is used to drive the reciprocating mechanism to drive the cylinder to extend and retract.

[0015] Optionally, the reciprocating mechanism comprises a rotating disc connected with the motor, a pivot shaft fixedly arranged at an eccentric position of the rotating disc, and a first connecting rod rotatably sleeved on the pivot shaft, one end of the first connecting rod is pivotally connected with a second connecting rod, and the other end of the first connecting rod is pivotally connected with the second connecting rod.

[0016] Optionally, the second connecting rod and the extension end of the cylinder are connected through a shaft coupling.

[0017] Optionally,

[0018] Optionally, the dynamic pressure signal generating device further comprises a base, a fixed plate is arranged at the upper end of the base, and the motor is fixedly arranged on the fixed plate.

[0019] Optionally, a linear bearing is fixedly arranged on the fixed plate, and the second connecting rod slidably penetrates through the linear bearing.

[0020] Optionally, the range of the absolute pressure sensor is ±20 PSI (±137900 Pa), and the accuracy is 0.04% (55 Pa); the range of the differential pressure sensor is ±1 PSI (±6895 Pa), and the accuracy is 0.1% (7 Pa).

[0021] Optionally, an electromagnetic valve is arranged on the second branch.

[0022] The above-mentioned embodiments of the utility model have the following beneficial effects:

[0023] The vacuum environment simulation device can simulate environmental pressure at different flight altitudes, thereby providing multiple simulation scenes. The pressure signal generating device can generate dynamic pressure signals with various amplitudes and frequencies under the control of the control device, thereby providing experimental conditions for measurement. By providing the first branch and the second branch, measurement of different Mach number ranges can be adapted, thereby improving the pertinence and accuracy of the measurement system. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the utility model or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0025] Figure 1 It is a structural schematic view of an embodiment of the micro-pressure pipeline delay time measurement system of the utility model;

[0026] Figure 2 It is a structural schematic view of an embodiment of the pressure signal generating device of the utility model;

[0027] Figure 3 It is the simulation waveform of the periodic pressure signal of the pressure signal generating device of the utility model;

[0028] Figure 4 It is the 250mm length pipeline delay measurement result of the utility model;

[0029] Figure 5 It is the 620mm length pipeline delay measurement result of the utility model.

[0030] BRIEF DESCRIPTION OF DRAWINGS:

[0031] 11, vacuum barrel; 12, vacuum pump;

[0032] 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, air cylinder;

[0033] 311, first branch; 312, absolute pressure sensor; 321, second branch; 322, differential pressure sensor; 323, electromagnetic valve;

[0034] 4, acquisition system;

[0035] 5. A processing system. DETAILED DESCRIPTION

[0036] The technical solutions of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0037] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0038] In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited. In addition, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication between two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0040] First, refer to Figure 1 , Figure 1 is a structural schematic view of an embodiment of the micro-pressure pipeline delay time measurement system of the present application. As Figure 1 shown, the micro-pressure pipeline delay time measurement system includes a vacuum environment simulation device, a communication-connected pressure signal generating device 2 and a control device, and a FADS pressure pipeline, a collection system 4 and a processing system 5 connected in turn.

[0041] The vacuum environment simulation device comprises a vacuum barrel 11 and a vacuum pump 12 connected with the vacuum barrel 11, and a precise digital absolute pressure gauge or a diaphragm vacuum gauge is arranged in the vacuum barrel 11, with a precision level of 0.05% F.S and a range of 0-101.3 kPa. During the measurement process, the aircraft model is placed in the vacuum barrel 11, and the environmental pressure value in the vacuum barrel 11 can be adjusted by controlling the vacuum pump 12, so as to simulate the flight height. For example, when the environmental pressure is 10 Pa, according to the standard atmospheric model, the simulated flight altitude is 65 km. The person skilled in the art can select the vacuum pump 12 with matched specifications and quantity according to the actual situation and design requirements.

[0042] Please refer to Figure 2 , Figure 2 The figure is a structural schematic diagram of an embodiment of the pressure signal generating device. Figure 2 As shown in the figure, 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 further arranged on the base 22, the motor 21 is fixed to one side of the fixed plate 221, and the transmission shaft of the motor 21 penetrates the fixed plate 221 and is connected with the reciprocating mechanism. The reciprocating mechanism comprises a rotating disc 23 connected with the transmission shaft of the motor 21, and a pivot shaft 24 is fixed to the eccentric position of the rotating disc 23. A first connecting rod 25 is rotatably sleeved on the pivot shaft 24, and the other end of the first connecting rod 25 is pivotally connected with a second connecting rod 26. The second connecting rod 26 is connected with the telescopic end of the cylinder 29 through a shaft coupling 28.

[0043] Further, in order to limit the movement direction of the second connecting rod 26, a linear bearing 27 is fixed to the fixed plate 221, and the second connecting rod 26 slidably penetrates the linear bearing 27.

[0044] The control device can be in communication connection with the dynamic pressure signal generating device 2, and the motor 21 of the dynamic pressure signal generating device 2 is controlled through the control device. As an example, the control device can be a central processing unit, a microprocessor or the like.

[0045] During the measurement process, the dynamic pressure signal generating device 2 is placed in the vacuum barrel 11, and the control device controls the motor 21 to work, so as to drive the rotating disc 23 and the pivot shaft 24 to rotate, so that the first connecting rod 25 acts on the second connecting rod 26, and the second connecting rod 26 can drive the telescopic end of the cylinder 29 to reciprocate along the linear bearing, so as to output the airflow by the cylinder 29 and blow to the aircraft model, simulate the periodic pressure signal, and the periodic pressure generating frequency is 3.3-7.6 hz. Thus, various dynamic pressure signals with different amplitudes and frequencies are generated. For details, please refer to Figure 3 , Figure 3 The figure is the simulated waveform of the periodic pressure signal of the pressure signal generating device.

[0046] The surface of the aircraft model is provided with a plurality of openings, and the opening diameter can be 1 mm. The openings can be 9, defined as P1-P9. Each opening is in communication with a main pipe of the FADS pressure measuring pipe, and the main pipe is divided into a first branch 311 and a second branch 321 through a tee. The first branch 311 can be directly connected to an absolute pressure sensor 312, and the second branch 321 is connected to a differential pressure sensor 322 after being connected to an electromagnetic valve 323. The range of the absolute pressure sensor 312 can be ±20 PSI (±137900 Pa), and the accuracy is 0.04% (55 Pa). The range of the differential pressure sensor 322 can be ±1 PSI (±6895 Pa), and the accuracy is 0.1% (7 Pa).

[0047] Figure 4 The 250mm length pipe delay measurement result of the utility model; Figure 5 The 620mm length pipe delay measurement result of the utility model. As shown in Figure 4 And Figure 5 As shown in the figure, the FADS pressure measuring pipe can be provided with different pipe diameters or lengths for comparative measurement.

[0048] The absolute pressure sensor 312 adopts a "single pipe" box shape packaging form, and the differential pressure sensor 322 adopts a "double pipe" box shape packaging form. The packaging box size is 38.1mmx38.1mmx43.18mm, and the output pipe has an inner diameter of 1mm and an outer diameter of 2mm.

[0049] The above-mentioned collection system 4 is in communication connection with the absolute pressure sensor 312 and the differential pressure sensor 322. As an example, the collection system 4 can be a USB5630 collection card, and the USB5630 can provide 32-way differential input collection. The analog input part of the USB5630 mainly consists of an AD analog quantity input port, an input selection module, a program-controlled amplifier, a low-pass filter, an analog-digital conversion, an AD buffer, a trigger and the like. The resolution of the collection card is 16 bits, and the highest sampling rate is 500kSPS.

[0050] The collection system 4 can record the real-time relationship between the output and the input pressure of the absolute pressure sensor 312 and the differential pressure sensor 322 during the measurement process, and evaluate the dynamic characteristics by analyzing the time domain and frequency domain responses. The dynamic response error and delay time can also be calculated by comparing the difference between the actual output and the ideal output.

[0051] The BP neural network technology and the CFD technology are used to establish a FADS solving algorithm based on the BP neural network. The aircraft surface pressure data measured by the absolute pressure sensor 312 of the first branch 311 are used to solve the aircraft surface pressure data, and the range of the Mach number Ma is judged.

[0052] The processing system 5 can be a DSP (Digital Signal Processing) and a FPGA (Field Programmable Gate Array) working in cooperation.

[0053] If Ma>0.2, the electromagnetic valve 323 of the second branch 321 is closed, the aircraft surface pressure data measured by the absolute pressure sensor 312 of the first branch 311 is used by the DSP, the pressure data is solved by the FADS algorithm to obtain the Mach number, static pressure, attack angle and sideslip angle and other flight parameters, the data is returned to the FPGA, and the flight flow parameter measurement result is output through the RS422.

[0054] If Ma≤0.2, the electromagnetic valve 323 of the second branch 321 is opened, the UAV surface pressure data measured by the differential pressure sensor 322 of the second branch 321 is used by the DSP, the vertex is still measured by the absolute pressure sensor 312, and the other P2-P9 is measured by the differential pressure sensor 322, which is measured by the differential pressure of P2-P9 with the vertex P1 pressure as the reference, and the absolute pressure of each point is obtained by adding the vertex P1. The pressure obtained by this method has high precision and is very beneficial to low Mach number segment pressure measurement. The pressure data is solved by the FADS algorithm to obtain the Mach number, static pressure, attack angle and sideslip angle and other flight parameters, the data is returned to the FPGA, and the flight flow parameter measurement result is output through the RS422.

[0055] That is, the absolute pressure sensor 312 and the differential pressure sensor 322 adopt different ranges and accuracies, which can adapt to different Mach number ranges.

[0056] The Mach number measurement range of the measurement system is 8-13, the static pressure height measurement range is 60-85km, and the attack angle and sideslip angle measurement range is-15°-15°.

[0057] After repeated verification, the measurement error (3σ) of the measurement system is: Mach number error ≤0.01, static pressure error ≤100Pa, attack angle 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).

[0058] 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 a transfer function. First of all, considering the processing of digital signals, it is more convenient to use the discrete system transfer function in the Z transform domain. Therefore, the discrete system transfer function model is used to identify the probe dynamic characteristics, and the m-order linear discrete system transfer function is

[0059]

[0060] Wherein, U(z) and Y(z) are respectively true value (pressure without pipeline transmission) and measured value (pressure after pipeline transmission);M represents order, which can be determined by experiment or public knowledge of those skilled in the art;a1···am and b0··bm are unknown parameters, which are determined by fitting, and d is lag, which can be determined by experiment or public knowledge of those skilled in the art.

[0061] U(z) and Y(z) are respectively Z transform of input and output signals, and time delay Td of input and output signals is a constant to be determined, and corresponding sampling point number is d = fs·Td.So this method needs to use differential equation of m-order discrete system model to identify unknown parameters a1···am, b0··bm.

[0062] The absolute pressure sensor and the differential pressure sensor are adopted, and the FADS solving algorithm is combined to control the electromagnetic valve to select the sensor group according to the Mach number range to measure the surface pressure value of the unmanned plane, so that the atmospheric data measurement in the low Mach number section and the high Mach number section is effectively solved.

[0063] The Mach number range of the application can be 8-13, most of the hypersonic flight speed range can be met, and high measurement accuracy can be obtained in the low Mach number section and the high Mach number section.

[0064] The absolute pressure sensor is packaged in a "single pipe" box shape, and the differential pressure sensor is packaged in a "double pipe" box shape.

[0065] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them;Although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features;And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

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

2. The micro-pressure pipeline delay time measurement system according to claim 1, characterized in that, The vacuum environment simulation device includes a vacuum tank, a vacuum pump connected to the vacuum tank, and a precision digital absolute pressure gauge installed inside the vacuum tank.

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

4. The micro-pressure pipeline delay time measurement system according to claim 1, characterized in that, The dynamic pressure signal generating device includes a motor, a reciprocating mechanism, and a cylinder connected in sequence to the control device. The motor is used to drive the reciprocating mechanism to extend and retract the cylinder.

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

7. The micro-pressure pipeline delay time measurement system according to claim 6, characterized in that, The dynamic pressure signal generator also includes a base, and a fixing plate is provided at the upper end of the base, and the motor is fixed to the fixing plate.

8. The system for measuring the delay time of a micro-pressure pipeline according to claim 7, characterized in that, A linear bearing is fixed on the fixed plate, and the second connecting rod can slide through the linear bearing.

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

10. The micro-pressure pipeline delay time measurement system according to claim 1, characterized in that, An electromagnetic valve is installed on the second branch.

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