Multi-redundancy aircraft wireless temperature and pressure sensor and control method

Abstract

The invention belongs to the field of aircraft wireless temperature and pressure sensors, and relates to a multi-redundancy aircraft wireless temperature and pressure sensor and a control method. The sensor comprises a multi-redundancy pressure sensitive assembly, a signal conditioning circuit, a Bluetooth transceiver module, a solid battery, a rear cover, a support and an outer cylinder. The pressure-sensitive assembly is welded to one end of the outer cylinder. The support is welded to the pressure-sensitive assembly. The Bluetooth transceiver module, the signal conditioning circuit and the solid battery are fixed on the bracket; the rear cover is in threaded connection with the outer cylinder; the pressure sensitive assembly is connected with an inner cavity of a tire through a pipeline and transmits pressure data to the signal conditioning circuit, and after the temperature measuring module measures the temperature, temperature and pressure signals are conditioned and calculated and then sent to a ground terminal through the Bluetooth receiving and transmitting module.

Description

Technical Field

[0001] The invention belongs to the field of temperature and pressure sensors, and in particular relates to a redundant aircraft wireless temperature and pressure sensor and a control method. Background Art

[0002] Wireless temperature and pressure sensors are an important part of aircraft tire health detection systems. Their function is to measure aircraft tire pressure and temperature. However, research institutions have done little research on redundant wireless temperature and pressure sensors. There are several main problems: a) Wireless sensors need to be in standby mode for a long time, and their standby power consumption needs to be very small. b) In order to improve the stability of the sensor, a redundant design is adopted, and each measurement part is independent of each other. c) The metal shell of the traditional sensor will have a shielding effect on the wireless signal, so it is necessary to increase the transmission distance of the wireless signal while ensuring the structural strength of the sensor.

[0003] Invention patent content

[0004] The purpose of the present invention is to provide a redundant aircraft wireless temperature and pressure sensor and a control method, the main function of which is to measure the temperature and pressure of aircraft tires. The redundant design and multi-channel independent pressure measurement improve the stability of the sensor. The low-power circuit design reduces the standby power consumption of the wireless sensor and increases the service life of the sensor. By adopting the inverted pressure core welding process, the pressure chip is directly welded to the base, the length of the nozzle is shortened, and the sensor is miniaturized. The non-metallic material shell is used to improve the sensor structure, improve the penetration of the wireless signal, and meet the transmission distance requirements.

[0005] The technical solution of the present invention is:

[0006] A redundant aircraft wireless temperature and pressure sensor, comprising: a redundant pressure sensitive component, a signal conditioning circuit board, a Bluetooth transceiver module, a solid battery, a back cover, a bracket and an outer tube;

[0007] The pressure sensitive component is welded to one end of the outer tube, and the bracket is welded to the pressure sensitive component;

[0008] The Bluetooth transceiver module, the signal conditioning circuit and the removable solid battery are fixed on the bracket;

[0009] The rear cover and the outer cylinder are sealed by an O-ring and connected by a snap-fit ​​groove;

[0010] The pressure sensitive component is connected to the inner cavity of the tire through a pipeline. The pressure sensitive component transmits the pressure data to the signal conditioning circuit, and after conditioning, it is sent to the terminal device through the Bluetooth transceiver module.

[0011] Furthermore, the redundant pressure sensitive component includes: at least two silicon piezoresistive chips, a nozzle, a sintered base and an outer cylinder, and multiple pressure cores independently measure tire pressure, thereby improving the stability of the sensor;

[0012] One end of the nozzle is connected to the inner cavity of the tire through a pipeline, and the other end is provided with an isolation diaphragm; the rear end of the isolation diaphragm and the core shell form a closed cavity;

[0013] The pressure core is welded on the sintered base and then placed in a closed cavity. The pressure core lead is led out through the core shell, which can filter impurities in the air in the tire cavity and improve the high temperature and high pressure resistance and corrosion resistance of the pressure core.

[0014] Furthermore, the back cover is made of non-metallic material, which extends the transmission distance of wireless signals.

[0015] Furthermore, the pressure core equivalent circuit is a Wheatstone bridge having five contacts, namely S1+, S11-, S12-, O1+, and O1-.

[0016] Furthermore, the core body corresponds to the signal conditioning chip one by one, and the connection relationship of the first signal conditioning circuit is as follows:

[0017] The IEXC1 pin is connected to the S1+ pin of the pressure core to provide a constant current source for the pressure core;

[0018] The VIP and VIN pins of the signal conditioning chip are connected to the O1+ and O1- pins of the pressure core respectively to measure the bridge arm voltage;

[0019] The S11- and S12- pins are connected to the AGND terminal of the circuit;

[0020] The IIC communication pins SDA and SCL of the signal conditioning chip transmit the measured values ​​of temperature and pressure to the Bluetooth transceiver module.

[0021] Furthermore, the Bluetooth transceiver module has a built-in microprocessor as a control module, which controls the transmission and reception of wireless signals, the encryption of temperature and pressure signals, and the sleep mode of the signal conditioning circuit respectively;

[0022] The control module controls the redundant pressure sensitive components and the signal conditioning circuit to work after receiving the inquiry signal;

[0023] After T time has passed since the pressure and temperature data were sent out, the control module controls the redundant pressure sensitive components and signal conditioning circuits to enter sleep mode, thereby reducing the standby power consumption of the sensor and extending the service life of the sensor.

[0024] Furthermore, the redundancy of the signal conditioning circuit is the same as the number of pressure cores, and the redundant signal conditioning circuits operate independently without interfering with each other, thereby improving the stability of the sensor.

[0025] A redundant aircraft wireless temperature and pressure sensor control method is used to control the redundant aircraft wireless temperature and pressure sensor, comprising the following steps:

[0026] Step 1: The control module detects whether the inquiry signal is received, if so, it proceeds to the next step, otherwise, it continues to step 1;

[0027] Step 2: The control module sends a high-level enable signal to the signal conditioning circuit. After receiving the enable signal, the signal conditioning circuit starts to work and supplies power to the redundant pressure sensitive components.

[0028] Step 3: The redundant pressure sensitive component feeds back the collected pressure data to the signal conditioning circuit;

[0029] Step 4: The signal conditioning circuit collects the ambient temperature;

[0030] Step 5: The signal conditioning circuit processes the pressure data and ambient temperature data and sends them to the control module;

[0031] Step 6: The control module calculates the pressure value and temperature value according to the pressure data, encrypts the pressure value and temperature value, and sends them through the Bluetooth transceiver module;

[0032] Step 7: The control module starts timing after sending the pressure value and temperature value. If no new inquiry signal is received within the timing time T, a low-level enable signal is sent after the timing ends to control the redundant pressure sensitive components and signal conditioning circuit to sleep, and return to step 1; if a new inquiry signal is received within the timing time T, return to step 2.

[0033] The beneficial effects of the present invention are as follows: the present invention belongs to the field of wireless temperature and pressure sensors, and relates to a redundant aircraft wireless temperature and pressure sensor. The present invention has the following advantages:

[0034] 1. Use low power consumption circuit design to extend the service life of the sensor.

[0035] 2. The redundant pressure sensitive component design improves the reliability of the sensor.

[0036] 3. The pressure core uses a flip-chip process to reduce the size of the sensor.

[0037] 4.3D printed inorganic non-metallic shell improves wireless signal transmission capability without reducing structural strength.

[0038] 5. Encrypt wireless signals to ensure information security. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the wireless temperature and pressure sensor;

[0040] Figure 2Schematic diagram of the pressure sensitive component structure;

[0041] Figure 3 Schematic diagram of the pressure core structure;

[0042] Figure 4 Schematic diagram of flip chip welding;

[0043] Figure 5 Schematic diagram of the connection between the outer cylinder and the rear cover

[0044] Figure 6 Schematic diagram of dedicated signal conditioning circuit;

[0045] Figure 7 Schematic diagram of equivalent circuit of pressure core;

[0046] Figure 8 Sensor circuit working flow diagram;

[0047] Fig. 9 Sensor control method flow chart;

[0048] In the figure, 1-redundant pressure sensitive component, 2-bracket, 3-outer cylinder, 4-signal conditioning circuit board, 5-Bluetooth transceiver module, 6-solid battery, 7-non-metallic back cover, 8-pipe nozzle, 9-pressure core, 10-signal conversion board, 11-core tube socket, 12-insulating base, 13-isolation diaphragm, 14-silicon piezoresistive chip, 15-core pin, 16-back cover buckle, 17-outer cylinder slot, 18-sealing O-ring. DETAILED DESCRIPTION

[0049] A redundant aircraft wireless temperature and pressure sensor, which includes a redundant pressure sensitive component, a signal conditioning circuit board, a Bluetooth transceiver module, a solid battery, a bracket and an outer tube. The pressure sensitive component adopts a redundant design, and the nozzle in the pressure sensitive component is connected to the inner cavity of the tire through a pipeline. At this time, the tire pressure acts on the multi-channel pressure core, and the pressure core senses the gas pressure and converts the gas pressure into a voltage signal. The voltage signal is sent to the sensor signal conditioning circuit through a filter circuit. The voltage signal is amplified and calibrated by a dedicated sensor signal conditioning chip, and the data is normalized to obtain the digital value of the pressure.

[0050] The main pressure-sensing element of the pressure core is the silicon piezoresistive chip. In order to meet the adaptability to high temperature, high pressure and corrosive environment, the pressure-sensing element needs to be packaged. The packaging structure of the pressure-sensing element mainly consists of a core tube seat, an insulating base isolation diaphragm, a silicon piezoresistive chip and a core pin. The silicon piezoresistive chip uses a flip-chip process to weld the front of the chip to the insulating base. The insulating base is installed in the tube seat, and the core pins pass through the insulating base. The outside of the tube seat is sealed with an isolation diaphragm to isolate the chip from the outside air. The pressure transmission path is that the pressure acts on the isolation diaphragm. Since the chip is sealed by the isolation diaphragm, when the tire pressure changes, the isolation diaphragm will transmit the pressure to the core.

[0051] The pressure core adopts a redundant design, with multiple silicon piezoresistive chips directly connected to the substrate with the front side facing downward, which improves the heat dissipation capacity of the core while reducing the size of the pressure core. Furthermore, the redundant pressure core can independently measure pressure information, and each sensor signal conditioning circuit is relatively independent. When one pressure core fails, the measurement of the other channel is not affected. This redundant design improves the reliability of the sensor.

[0052] The metal shell of traditional sensors will shield wireless signals. In order to improve the signal strength, inorganic non-metallic materials are used to improve the design of the sensor outer tube. However, the adhesive or threaded connection strength between non-metallic materials and metal materials is weak, which will affect the overall environmental adaptability of the sensor. This solution uses 3D printed inorganic non-metallic materials to design a non-metallic back cover; the outer tube and the non-metallic back cover are connected by a card slot buckle; after the two are combined through the threading hole, a fuse is installed to prevent the back cover from loosening during vibration; to ensure the sealing performance, an O-ring is used to seal between the outer tube and the non-metallic back cover; this design ensures signal transmission while taking into account the structural strength of the sensor.

[0053] The multi-channel signal conditioning circuit uses a separate constant current source to power the pressure core. The constant current source has the advantages of high stability, strong resistance to load changes, long-term stable operation and no temperature influence. The power supply and calibration output of the multi-channel pressure measurement are independent of each other. This redundancy design improves the reliability of the sensor.

[0054] In order to meet the requirements of the service life of wireless sensors, the standby time of traditional sensors powered by solid batteries can only be maintained from a few days to more than ten days, and the battery needs to be replaced frequently. Therefore, new requirements need to be put forward for the power consumption of the sensor. The present invention adopts an intelligent sleep design for each circuit of the sensor. After the T time interval after the data is sent, the sensor automatically enters the sleep mode, the microprocessor controls the dedicated signal conditioning chip to enter the low power mode, and turns off the constant current source power supply of the pressure core, reducing the standby power consumption of the sensor to the nanoampere level. This solution can extend the service life of the wireless sensor to more than three years without replacing the battery.

[0055] When an external device needs to read tire temperature and pressure data, it will encrypt the query command to the Bluetooth transceiver module according to the custom protocol. The sensor Bluetooth transceiver module has a microprocessor, which will perform decoding operations according to the query command. When the signal meets the requirements, the sensor circuit will be awakened and the measured temperature and pressure signal will be encrypted and sent to the designated host. The encryption of wireless signals ensures the security of the wireless network.

[0056] The working principle of the redundant aircraft wireless temperature and pressure sensor is as follows: when the Bluetooth transceiver module receives the inquiry signal and is decoded and confirmed by the microprocessor, an enable signal is sent to the multi-channel signal conditioning circuit. After receiving the enable signal, the multi-channel signal conditioning circuit activates the pressure core to provide constant current power supply. After the silicon piezoresistive chip on the pressure core senses the tire pressure, the signal conditioning chip measures the core output voltage and outputs the normalized pressure value after calibration. In addition, the signal conditioning chip measures the ambient temperature through the on-board temperature measurement module, and sends the temperature and pressure measurement data to the microprocessor of the Bluetooth transceiver module through the IIC communication protocol. The microprocessor calculates the temperature and pressure values ​​of the temperature and pressure measurement data and encrypts the data, which is sent to the terminal device by the Bluetooth transceiver antenna. After the transmission is completed, if no new inquiry signal is received within the T waiting time, the microprocessor sends an enable shutdown signal to the multi-channel signal conditioning circuit, and the sensor enters a dormant state.

[0057] The redundant aircraft wireless temperature and pressure sensor includes a pressure sensitive component, a signal conditioning circuit, a wireless transceiver module, a battery and a sensor housing, etc. The following is a diagram for explanation.

[0058] like Figure 1 As shown, the sensor includes a redundant pressure sensitive component, a bracket, an outer tube, a signal conditioning circuit, a Bluetooth transceiver module, a solid battery and a non-metal back cover. The pressure sensitive component and the outer tube are welded to the bracket, the signal conditioning circuit board, the solid battery and the Bluetooth transceiver module are fixed to the bracket with screws, and the non-metal and the outer tube are sealed with an O-ring and fixed to the outer tube through a card slot buckle.

[0059] like Figure 2 As shown in the figure, the pressure sensitive assembly includes a take-off nozzle, a pressure core and a signal conversion board. The pressure core is welded inside the take-off nozzle.

[0060] like Figure 3 As shown, the pressure core includes a core body tube seat, an insulating base, an isolation diaphragm, a silicon piezoresistive chip and a core body pin. The core body tube seat, the insulating base and the isolation diaphragm weld and seal the silicon piezoresistive chip inside the core body using a flip chip process, and the chip port is led out through the pin.

[0061] like Figure 4 As shown, the chip of the flip-chip core is fixed on the core base through an insulating base.

[0062] like Figure 5As shown, the buckle on the outside of the rear cover is connected with the groove on the inside of the outer tube to tighten the sealing O-ring.

[0063] like Figure 6 As shown, one of the dedicated signal conditioning circuit schematics has a front end connected to the pressure core pin and a back end transmitted to the microprocessor via IIC communication.

[0064] like Figure 7 Shown is a schematic diagram of the equivalent circuit of a silicon piezoresistive chip.

[0065] like Figure 8 and Fig. 9 Shown are the sensor circuit working flow chart and the sensor control method flow chart.

Claims

1. A redundant aircraft wireless temperature and pressure sensor, characterized in that: Sensors include: Redundancy pressure sensitive components, signal conditioning circuit, Bluetooth transceiver module, solid battery, back cover, bracket and outer tube; The pressure sensitive component is welded to one end of the outer tube, and the bracket is welded to the pressure sensitive component; The Bluetooth transceiver module, the signal conditioning circuit and the solid battery are fixed on the bracket; The rear cover and the outer cylinder are sealed by an O-ring and connected by a snap-fit ​​groove; The pressure sensitive component is connected to the inner cavity of the tire through a pipeline. The pressure sensitive component transmits the pressure data to the signal conditioning circuit, which is then sent to the ground terminal through the Bluetooth transceiver module after conditioning.

2. The redundant aircraft wireless temperature and pressure sensor according to claim 1, characterized in that: The redundant pressure sensitive component comprises: at least two silicon piezoresistive chips, a nozzle, a sintered base and an outer cylinder; One end of the nozzle is connected to the inner cavity of the tire through a pipeline, and the other end is provided with an isolation diaphragm; the rear end of the isolation diaphragm and the core shell form a closed cavity; The pressure core is welded on the sintered base and arranged in the closed cavity, and the pressure core lead is led out through the core shell.

3. The redundant aircraft wireless temperature and pressure sensor according to claim 2, characterized in that: The back cover is made of non-metallic material.

4. The redundant aircraft wireless temperature and pressure sensor according to claim 3, characterized in that: The pressure core equivalent circuit is a Wheatstone bridge with five contacts, namely S1+, S11-, S12-, O1+, and O1-.

5. The redundant aircraft wireless temperature and pressure sensor according to claim 4, characterized in that: The core body corresponds to the signal conditioning chip one by one. Taking the first signal conditioning circuit as an example, the specific connection relationship is as follows: The IEXC1 pin is connected to the S1+ pin of the pressure core; The VIP and VIN pins of the signal conditioning chip are connected to the O1+ and O1- pins of the pressure core respectively; The S11- and S12- pins are connected to the AGND terminal of the circuit; The IIC communication pins SDA and SCL of the signal conditioning chip are connected to the Bluetooth transceiver module circuit.

6. The redundant aircraft wireless temperature and pressure sensor according to claim 5, characterized in that: The Bluetooth transceiver module has a built-in microprocessor as a control module; The control module controls the redundant pressure sensitive components and the signal conditioning circuit to work after receiving the inquiry signal; After T time has passed since the pressure and temperature data were sent out, the control module controls the redundant pressure sensitive components and the signal conditioning circuit to enter the sleep mode.

7. The redundant aircraft wireless temperature and pressure sensor according to claim 6, characterized in that: The signal conditioning circuit redundancy is the same as the number of pressure cores.

8. A method for controlling a redundant aircraft wireless temperature and pressure sensor, used to control the redundant aircraft wireless temperature and pressure sensor according to any of the preceding claims, characterized in that: The following steps are involved: Step 1: The control module detects whether the inquiry signal is received, if so, it proceeds to the next step, otherwise, it continues to step 1; Step 2: The control module sends a high-level enable signal to the signal conditioning circuit. After receiving the enable signal, the signal conditioning circuit starts to work and supplies power to the redundant pressure sensitive components. Step 3: The redundant pressure sensitive component feeds back the collected pressure data to the signal conditioning circuit; Step 4: The signal conditioning circuit collects the ambient temperature; Step 5: The signal conditioning circuit processes the pressure data and ambient temperature data and sends them to the control module; Step 6: The control module calculates the pressure value and temperature value according to the pressure data, encrypts the pressure value and temperature value, and sends them through the Bluetooth transceiver module; Step 7: The control module starts timing after sending the pressure value and temperature value. If no new inquiry signal is received within the timing time T, a low-level enable signal is sent after the timing ends to control the redundant pressure sensitive components and signal conditioning circuit to sleep, and return to step 1; if a new inquiry signal is received within the timing time T, return to step 2.

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