Split type multi-redundancy air pressure height sensor for ejection seat

Abstract

The invention belongs to the field of digital pressure sensor design, and particularly relates to a split type multi-redundancy air pressure height sensor for an ejection seat. An existing air pressure height sensor product cannot meet the use requirement of an ejection seat. The device comprises a redundancy pressure sensitive assembly and a signal conditioning module which are spatially isolated, the redundancy pressure sensitive assembly and the signal conditioning module are connected through a cable and an electric connector, the redundancy pressure sensitive assembly comprises a filler neck, a sintering base, a conversion plate and an outer sleeve which are sequentially connected and installed, and a plurality of packaged pressure sensors are arranged in the filler neck. The air pressure height measurement function in the flight process of an aircraft and after ejection of a seat can be completed, meanwhile, the requirement for quick response is met by adopting a hardware and software collaborative design mode, and the requirements for impact resistance, high temperature resistance and easy installation of the sensor are met by adopting the split design of the multi-redundancy pressure sensor and the sensor signal conditioning module.

Description

Technical Field

[0001] The invention belongs to the field of digital pressure sensor design, and in particular relates to a split redundant air pressure altitude sensor for an ejection seat. Background Art

[0002] The ejection seat air pressure altitude sensor is the main component for measuring environmental parameters of the ejection seat. Its function is to measure the pressure data of the aircraft during flight and after the seat is ejected. The pressure signal is converted into an electrical signal through the pressure sensitive component and input into the single-chip microcomputer for solution to obtain the altitude information of the air pressure position.

[0003] The application environment of the ejection seat air pressure altitude sensor has special requirements on its power-on response time, impact resistance, miniaturization, safety stability and installation adaptability. The existing air pressure altitude sensor products cannot meet the use requirements of the ejection seat. Summary of the invention

[0004] The present invention provides a split redundant air pressure altitude sensor for an ejection seat, which can complete the air pressure altitude measurement function during the flight of an aircraft and after the seat is ejected, and at the same time adopts a hardware and software collaborative design method to meet the demand for rapid response. By adopting a split design of a redundant pressure sensor and a sensor signal conditioning module, the requirements of the sensor being impact-resistant, high-temperature-resistant and easy to install are achieved.

[0005] The present invention provides a split redundant air pressure altitude sensor for an ejection seat, comprising a redundant pressure sensitive component and a signal conditioning module which are spatially isolated, and the two are connected by cables and an electrical connector, wherein the redundant pressure sensitive component comprises a nozzle, a sintered base, a conversion plate and an outer sleeve which are sequentially connected and installed, wherein a plurality of packaged pressure sensors are arranged in the nozzle; the signal conditioning module comprises a power module, a signal conditioning circuit, a single chip microcomputer and a communication module, wherein the signal conditioning circuit amplifies and calibrates a voltage signal and normalizes the data, and then the altitude information calculated by the single chip microcomputer is outputted to the ejection seat controller by the communication module.

[0006] Advantageously, the filler nozzle and the pressure sensor are integrally sealed and welded.

[0007] Advantageously, each pressure sensor has independent signal conditioning circuitry.

[0008] Advantageously, the single chip microcomputer verifies the accuracy of the input through the historical information comparison function, and after verification, the digital quantity of the voltage signal is resolved to obtain the three-way height value.

[0009] Advantageously, the power module outputs the 5V power supply of the seat system as 3.3V after filtering and stabilization to power the signal conditioning circuit and the single-chip microcomputer.

[0010] Advantageously, the signal conditioning circuit supplies power to the pressure sensitive components of the corresponding circuit via a constant current source.

[0011] Advantageously, the communication module receives the working instruction of the host computer and sends the height value data and sensor channel status word packaged by the single chip microcomputer through the communication protocol.

[0012] Advantageously, the pressure sensor is composed of multiple silicon piezoresistive chips.

[0013] Advantageously, the signal conditioning circuit collects temperature information using an internal temperature sensor and calibrates the voltage.

[0014] Advantageously, the single chip microcomputer mutually checks the height values ​​of the three paths. When it is found that one path exceeds the alarm threshold, the single chip microcomputer sends an error status word of the path to remind the operator that the path has a fault and measures need to be taken.

[0015] Beneficial effects: The present invention belongs to the field of pressure sensors, and relates to a split redundant air pressure altitude sensor for ejection seats. In the application field of atmospheric pressure sensors for military ejection seats, the power-on response time is greatly shortened through the collaborative design of hardware and software, and the safety and reliability of the sensor are improved. The split design improves the impact resistance and high temperature resistance of the sensor, and the sealed welding design achieves the goal of miniaturization of the sensor.

[0016] By isolating the pressure sensitive component from the signal conditioning component in space, the installation problem of the ejection seat with limited space is reduced and solved, and the temperature abnormality problem caused by air friction is avoided. In addition, connecting the pressure sensitive component and the circuit board through the electrical connector wire also avoids the impact force on the circuit board during high-speed ejection.

[0017] The invention has great practical application value.

[0018] The features, functions, and advantages that have been discussed can be achieved independently in various examples or may be combined in yet other examples. Further details of the examples can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Examples, as well as preferred modes of use, other objects and description thereof, will be best understood by reference to the following detailed description of examples of the invention when read in conjunction with the accompanying drawings, in which:

[0020] Figure 1 It is a schematic diagram of the composition of the redundant pressure sensitive component;

[0021] Figure 2 is the schematic diagram of the equivalent circuit of the pressure sensor;

[0022] Figure 3 is a schematic diagram of the signal conditioning circuit;

[0023] Figure 4 It is a schematic diagram of the power supply circuit;

[0024] Figure 5 It is a schematic diagram of the microcontroller circuit interface;

[0025] Figure 6 It is a schematic diagram of bus transceiver circuit;

[0026] Figure 7 It is a control flow chart.

[0027] 1. Take-over nozzle, 2. Sintered base, 3. Conversion plate, 4. Outer sleeve, 5. Cable, 6. Electrical connector DETAILED DESCRIPTION

[0028] The disclosed examples will be more fully described with reference to the accompanying drawings, in which some (but not all) of the disclosed examples are shown. In fact, many different examples may be described and these examples should not be construed as limited to the examples set forth herein. Instead, these examples are described so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those skilled in the art.

[0029] The split redundant air pressure altitude sensor includes a redundant pressure sensitive component and a signal conditioning module. In order to meet the requirements of the sensor's impact resistance, high temperature resistance, and installation flexibility, the present invention adopts a split design of the pressure sensitive component and the signal conditioning module, separates the pressure sensitive component from the signal conditioning module in space, and connects them through wires and electrical connectors. The cable of the electrical connector is protected by a wave-proof sleeve and nylon yarn winding, which can isolate the impact of the external pressure pipeline while isolating the high temperature caused by pneumatic heating.

[0030] The following is a detailed introduction of the redundant pressure sensor using a three-way independent design as an example.

[0031] like Figure 1 As shown, the redundant pressure sensitive component includes a nozzle 1 containing a pressure sensor, a sintered base 2, a conversion board 3, an outer sleeve 4, a cable 5 and an electrical connector 6. The nozzle 1 connects the outside world with the pressure sensor, and introduces the atmospheric pressure into the nozzle 1. At this time, the atmospheric pressure acts on the multi-channel pressure sensor, and the pressure sensor senses the atmospheric pressure and converts the atmospheric pressure into three-channel electrical signals.

[0032] The main pressure-sensitive element of the pressure sensor is the silicon piezoresistive chip. In order to meet the adaptability to high temperature, high pressure and corrosive environment, the pressure-sensitive element needs to be packaged. The packaging structure of the pressure-sensitive element is mainly composed of a pressure ring, an isolation diaphragm, a silicon piezoresistive chip, a liner, a tube shell, pins, and silicone oil. The pressure transmission path is that the pressure acts on the isolation diaphragm, which transmits the pressure to the isolation diaphragm. The deformation of the isolation diaphragm transmits the pressure to the silicone oil. Since the silicone oil is incompressible, it transmits the pressure to the silicon piezoresistive chip.

[0033] Each sensor can measure pressure information independently, and the signal conditioning process is independent of each other. When one pressure sensor fails, the measurement of the other one is not affected. The use of redundant pressure sensitive component solutions can effectively avoid the serious consequences caused by single-channel failures. In addition, packaging multiple pressure sensors in one pressure sensitive component can effectively reduce the volume. In order to achieve the miniaturization requirements of the ejection seat air pressure height sensor, the nozzle 1 and the pressure sensor are designed with an integrated sealed welding design based on the design of the traditional pressure sensitive component to reduce the volume of the pressure sensitive component.

[0034] like Figure 2 The figure shows the equivalent circuit diagram of the silicon piezoresistive chip. Four varistors are connected in the form of a Wheatstone bridge. When the chip is subjected to external pressure, the resistance of the varistor in the bridge arm changes. By measuring the differential voltage of the bridge, the pressure signal is converted into a voltage signal.

[0035] The signal conditioning module includes a power module, a signal conditioning circuit, a single-chip microcomputer and a communication module. The power module stabilizes, filters and protects the external 5V power supply of the ejection seat, and outputs the voltage required by the multi-channel signal conditioning circuit and the single-chip microcomputer for power supply. The multi-channel signal conditioning circuit can also use an independent constant current source to power the pressure sensor. The constant current source power supply has the advantages of high stability, strong resistance to load changes, long-term stable operation and no temperature influence. This redundant design improves the stability of the sensor.

[0036] like Figure 3 As shown, the stable voltage signal is sent to the signal conditioning circuit through the RC filter circuit. The signal conditioning circuit amplifies and calibrates the voltage signal and normalizes the data. The multi-channel normalized data is then resolved by the single-chip microcomputer, and the normalized electrical signal is resolved into altitude information and output to the ejection seat controller through the bus communication module.

[0037] The signal conditioning circuit supplies power to the corresponding pressure sensitive components through the power module. The pressure sensor generates a voltage signal after measuring the atmospheric pressure and transmits the pressure signal to each signal conditioning circuit through the electrical connector 6. The signal conditioning circuit calibrates each pressure signal and outputs a proportional pressure signal. In the process of pressure collection of the signal conditioning circuit, the internal temperature sensor is also used to collect temperature information. The calibrated voltage output can effectively reduce the influence of temperature on the sensor output.

[0038] like Figure 4 As shown, the power circuit module filters and stabilizes the 5V power supply of the seat system and outputs it as a 3.3V power supply to power the signal conditioning circuit and the single-chip microcomputer, thereby improving the stability of the sensor.

[0039] like Figure 5 As shown, the single-chip microcomputer converts the pressure signal of the signal conditioning circuit into a digital signal through the A / D acquisition interface, verifies the accuracy of the input through the historical information comparison function, and solves the digital value of the voltage signal to obtain the height value after verification. The three-way height value is checked against each other through the solution. When it is found that one way exceeds the alarm threshold, the single-chip microcomputer sends the error status word of the way to remind the operator that measures need to be taken when the way fails. It is worth noting that the above solution process is independent and will not interrupt or affect the operation of the sensor. This solution solves the problem of fault location, reduces the impact caused by the fault, and improves the reliability of the sensor.

[0040] Figure 6 It is a bus transceiver module, which can receive the working instructions of the host computer and send the height value data packaged by the microcontroller through the communication protocol.

[0041] like Figure 7 As shown in the figure, the source code values ​​of temperature and pressure are collected by the single-chip microcomputer, calculated as temperature values ​​and pressure values, and then the voltage value is converted into a height value. In addition, the historical information review and threshold alarm functions are added to the single-chip microcomputer software to improve the stability of the sensor. The historical information comparison function is to establish a corresponding relationship between the historical input voltage signal of the single-chip microcomputer and the output height value, and obtain the historical output height value corresponding to each pressure signal. When the output height value of a certain channel is inconsistent with the history, the single-chip microcomputer will send an error status word to the host computer. In addition, the difference of multiple input pressure values ​​is calculated. When the difference exceeds the set threshold, the single-chip microcomputer will send an alarm status word to remind the operator, so that timely measures can be taken to avoid safety accidents and improve the safety and reliability of the sensor.

[0042] Considering the high safety and high reliability requirements of the ejection seat air pressure altitude sensor, the power-on response time of the traditional sensor design method is generally more than 1s, which cannot meet the use requirements of the ejection seat. The present invention shortens the sensor power-on response time from more than 1s to less than 60ms by adopting the collaborative design of hardware and software, thereby improving the reliability of the ejection seat air pressure altitude sensor.

[0043] Descriptions of different advantageous arrangements have been presented for purposes of illustration and description, but the description is not intended to be exclusive or limited to examples of the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. Additionally, different advantageous examples may be described as having different advantages over other advantageous examples. The selected example or examples are selected and described in order to best illustrate the principles of the examples, practical applications, and to enable those of ordinary skill in the art to understand the disclosure as having various examples with various modifications suitable for the particular use contemplated.

Claims

1. A split redundant air pressure altitude sensor for an ejection seat, characterized in that: The invention comprises a redundant pressure sensitive component and a signal conditioning module which are spatially isolated and connected via a cable (5) and an electrical connector (6). The redundant pressure sensitive component comprises a nozzle (1), a sintered base (2), a conversion plate (3) and an outer sleeve (4) which are sequentially connected and installed, wherein a plurality of packaged pressure sensors are provided in the nozzle (1); the signal conditioning module comprises a power supply module, a signal conditioning circuit, a single-chip microcomputer and a communication module. The signal conditioning circuit amplifies and calibrates the voltage signal and normalizes the data. The altitude information calculated by the single-chip microcomputer is then outputted to the ejection seat controller by the communication module.

2. The split type redundant air pressure altitude sensor according to claim 1, characterized in that: The nozzle (1) and the pressure sensor are integrally sealed and welded.

3. The split type redundant air pressure altitude sensor according to claim 1, characterized in that: Each pressure sensor has independent signal conditioning circuit.

4. The split type redundant air pressure altitude sensor according to claim 1, characterized in that: The single chip microcomputer verifies the accuracy of the input through the historical information comparison function, and after verification, the digital quantity of the voltage signal is solved to obtain the three-way height value.

5. The split type redundant air pressure altitude sensor according to claim 1, characterized in that: The power module is used to filter and stabilize the 5V power supply of the seat system and output it to 3.3V to power the signal conditioning circuit and the single-chip microcomputer.

6. The split type redundant air pressure altitude sensor according to claim 1, characterized in that: The signal conditioning circuit supplies power to the pressure sensitive components of the corresponding circuit through a constant current source.

7. The split type redundant air pressure altitude sensor according to claim 1, characterized in that: The communication module receives the working instruction of the host computer and sends the height value data and the sensor channel status word packaged by the single chip computer through the communication protocol.

8. The split type redundant air pressure altitude sensor according to claim 1, characterized in that: The pressure sensor is composed of multiple silicon piezoresistive chips.

9. The split type redundant air pressure altitude sensor according to claim 1, characterized in that: The signal conditioning circuit collects temperature information using an internal temperature sensor and calibrates the voltage.

10. The split type redundant air pressure altitude sensor according to claim 1, characterized in that: The single chip microcomputer mutually checks the height values ​​of the three paths. When it is found that one path exceeds the alarm threshold, the single chip microcomputer sends the error status word of the path to remind the operator that the path has a fault and measures need to be taken.

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