A method for detecting abnormal water accumulation in an L-shaped airspeed tube air path of a helicopter

Abstract

The application provides a kind of helicopter L-shaped air speed pipe gas path water accumulation abnormality detection method, belongs to helicopter L-shaped air speed pipe gas path water accumulation abnormality detection field, the method includes: using metal pipeline, constructs air speed pipe gas path, air speed pipe gas path is connected with atmosphere data computer, and metal probe sensor is installed in total pressure gas path and static pressure gas path;Metal probe sensor is connected with atmosphere data computer, and the down pull resistance formed by rain is obtained using metal probe sensor and metal pipeline;Based on the down pull resistance formed by rain, water accumulation abnormality detection is carried out using the signal acquisition circuit of atmosphere data computer, and the air speed pipe gas path water accumulation abnormality detection result is obtained;The application solves the problem that the existing aircraft air speed pipe cannot carry out gas path water accumulation detection.

Description

Technical Field

[0001] This invention belongs to the field of abnormal water accumulation in the air passage of a helicopter L-type pitot tube, and particularly relates to a method for abnormal water accumulation in the air passage of a helicopter L-type pitot tube. Background Technology

[0002] The pitot tube is the core sensor on an aircraft for measuring flight speed. It calculates atmospheric parameters such as barometric altitude and indicated airspeed by sensing airflow pressure, providing pilots with critical data that directly affects flight control and safety. Piston tubes generally have two air passage interfaces, one for total pressure and one for static pressure, and are designed with drainage holes. They are usually installed at the front of the aircraft. When parked on the ground, a protective cover is used to cover the pitot tube to prevent foreign objects from entering the total pressure or static pressure air passages and causing blockage.

[0003] When aircraft are in flight, their protective covers are removed. In heavy rain, water can overflow the pitot tube's drain hole, causing water accumulation in the air passages. Fixed-wing aircraft, generally operating at higher speeds, can use air pressure differences to drain water from the total pressure passages to the settler. While water may accumulate in the static pressure passages, it can be resolved through other static pressure holes on the aircraft. Helicopters, however, generally fly at lower speeds, making it more difficult to drain water from the total pressure passages to the settler using air pressure differences. Furthermore, the L-shaped pitot tube has its own static pressure hole, making it difficult to remove water from the static pressure passages once it enters.

[0004] Water ingress into the pitot tube is a high-risk malfunction during aircraft flight. The core hazard is that it causes distortion of critical flight data such as indicated airspeed and barometric altitude. The air data computer cannot identify the distorted data malfunction and will not report the relevant malfunction alarm. If the pilot uses the distorted data, it may directly affect flight safety and cause a flight accident. According to the research on pitot tube water ingress detection functions, the existing aircraft pitot tubes only use structural design to avoid water accumulation inside the pitot tube, but none of them have a water accumulation detection design in the air passage. Summary of the Invention

[0005] To address the aforementioned shortcomings in the existing technology, this invention provides a method for detecting abnormal water accumulation in the air passage of a helicopter L-type pitot tube, which solves the problem that existing aircraft pitot tubes cannot detect water accumulation in the air passage.

[0006] To achieve the above objectives, the technical solution adopted by this invention is as follows: a method for detecting abnormal water accumulation in the air passage of a helicopter L-type airspeed tube, comprising the following steps: S1. Construct an airspeed pipeline using metal tubing, connect the airspeed pipeline to the air data computer, and install the metal probe sensor in the main pressure pipeline and static pressure pipeline. S2. Connect the metal probe sensor to the atmospheric data computer, and use the metal probe sensor and metal pipeline to obtain the pull-down resistance formed by rainwater. S3. Based on the pull-down resistor formed by rainwater, the signal acquisition circuit of the atmospheric data computer is used to detect water accumulation anomalies and obtain the detection results of water accumulation anomalies in the airflow path of the airspeed tube.

[0007] The beneficial effects of this invention are as follows: By installing a metal probe sensor on the air passage of the L-shaped pitot tube of a helicopter, this invention can collect the water accumulation status of the L-shaped pitot tube air passage in real time, and report the water accumulation fault status of each air passage in the pitot tube in real time through an atmospheric data computer. This solves the problem of atmospheric parameter distortion caused by water accumulation in helicopters, avoids pilots using distorted data to affect flight safety and cause flight accidents, improves the flight safety of aircraft, and provides a solution for detecting water accumulation in the air passage of aircraft pitot tubes.

[0008] Further, S1 includes the following steps: S101. Construct a pneumatic tube using metal tubing and connect the pneumatic tube to the digital ground of the air data computer. S102. Based on the air velocity pipe air path, the metal probe sensor is installed at the rear end of the drain hole of the main pressure air path and the static pressure air path and at the center of the cross section of each air path.

[0009] The beneficial effects of the above-mentioned further solutions are as follows: By adding metal probe sensors to each air passage of the helicopter L-type pitot tube, and specifically installing them at the rear end of the drain hole of the total pressure air passage and the static pressure air passage and at the center of the cross section of each air passage, the present invention can collect the water accumulation status of each air passage of the L-type pitot tube in real time, providing a high-precision data basis for anomaly detection.

[0010] Furthermore, S2 includes the following steps: S201. Connect the metal probe sensor wire to the signal acquisition circuit of the atmospheric data computer. S202. Using the distance between the metal probe sensor and the metal pipe and the resistivity of rainwater, the pull-down resistance formed by rainwater between the metal probe sensor and the metal pipe is calculated.

[0011] Furthermore, the calculation expression for the pull-down resistor formed by the rainwater is as follows:

[0012] in, This indicates the pull-down resistor formed by rainwater. This indicates the distance between the metal probe sensor and the metal conduit. This indicates the resistivity of rainwater.

[0013] The beneficial effects of the above-mentioned further solution are as follows: The present invention uses a metal probe sensor and a signal acquisition circuit to calculate and form a pull-down resistor through the metal probe sensor, metal pipeline and rainwater, thereby providing a detection basis for subsequent fault detection.

[0014] Furthermore, step S3 includes the following steps: S301. Based on the pull-down resistor formed by rainwater, the signal acquisition circuit of the atmospheric data computer is used to detect abnormal water accumulation. In response to water accumulation in the air path of the air speed tube, the PNP power transistor in the water accumulation detection circuit is used to collect the water accumulation signal, and the water accumulation signal is used to drive the relay to form a fault alarm circuit loop. S302. Based on the fault alarm circuit loop, a visual alarm signal is emitted by lighting up the fault alarm light, and the optocoupler is stopped from working. The optocoupler output terminal level containing the fault signal is output through the optocoupler output terminal. S303. In response to the normal airflow path of the airspeed tube, the metal probe sensor is opened from the metal tube. The PNP power transistor in the signal acquisition circuit is pulled up to the preset level through the pull-up resistor. The optocoupler is then put into normal operation. The optocoupler output terminal level containing the fault-free signal is output. S304. The atmospheric data computer collects the output level of the optocoupler, identifies the water accumulation information of the total pressure air path and static pressure air path, and combines it with the visual alarm signal to obtain the abnormal detection result of water accumulation in the air speed tube.

[0015] Furthermore, the signal acquisition circuit includes: a first water accumulation detection circuit and a second water accumulation detection circuit; The first water accumulation detection circuit is used to detect static pressure air path and includes: resistor R1, resistor R2, resistor R3, relay K1, diode V1, PNP power transistor Q1, fault alarm light LED1 and optocoupler K2. The base of the PNP power transistor Q1 is connected to the first metal probe sensor wire and one end of resistor R3; the emitter of the PNP power transistor Q1 is connected to the ground pin of relay K1 and the anode of diode V1; the other end of resistor R3 is connected to the cathode of diode V1, the power supply pin of relay K1, one end of resistor R1, and DC15V; the other end of resistor R1 is connected to the common terminal of relay K1; the normally open contact of relay K1 is connected to the anode of fault alarm LED1; and the normally closed contact of relay K1 is connected to pin 1 of optocoupler K2. The drain of the PNP power transistor Q1 is connected to the negative terminal of the fault alarm light LED1, pin 2 and pin 3 of the optocoupler K2, and then to digital ground; pin 4 of the optocoupler K2 is connected to one end of the resistor R2 and the optocoupler output terminal Ps_out; the other end of the resistor R2 is connected to DC 3.3V.

[0016] Furthermore, the second water accumulation detection circuit, used to detect the main air pressure circuit, includes: resistor R4, resistor R5, resistor R6, relay K3, diode V2, PNP power transistor Q2, fault alarm light LED2, and optocoupler K4. The base of the PNP power transistor Q2 is connected to the second metal probe sensor wire and one end of resistor R6; the emitter of the PNP power transistor Q2 is connected to the ground pin of relay K3 and the anode of diode V2; the other end of resistor R6 is connected to the cathode of diode V2, the power supply pin of relay K3, one end of resistor R5, and DC15V; the other end of resistor R5 is connected to the common terminal of relay K3; the normally open contact of relay K3 is connected to the anode of fault alarm LED2; and the normally closed contact of relay K3 is connected to pin 1 of optocoupler K4. The drain of the PNP power transistor Q2 is connected to the negative terminal of the fault alarm light LED2, pin 2 of the optocoupler K4, and pin 3 of the optocoupler K2, and is connected to digital ground; pin 4 of the optocoupler K4 is connected to one end of the resistor R4 and the optocoupler output terminal Ps_out; the other end of the resistor R4 is connected to DC 3.3V.

[0017] The beneficial effects of the above-mentioned further solutions are as follows: the present invention detects water accumulation anomalies through a signal acquisition circuit, reports fault status through visualized information and data information, improves the real-time performance of fault detection, and provides a rapid detection solution for emergency response procedures. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method of the present invention.

[0019] Figure 2 This is a schematic diagram of the assembly of the metal probe sensor in the L-shaped pitot tube in this embodiment.

[0020] Figure 3 This is a partially enlarged schematic diagram of the gas path cross-section in this embodiment.

[0021] Figure 4 This is a circuit diagram of the signal acquisition circuit of the atmospheric data computer in this embodiment.

[0022] Figure 5 This is a flowchart of the signal acquisition circuit in this embodiment. Detailed Implementation

[0023] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0024] Before describing this embodiment, the following terms will be explained: DGND: Digital Land; Ps air path: static pressure air path; Pt gas path: Total pressure gas path.

[0025] Example like Figure 1 As shown, this invention provides a method for detecting abnormal water accumulation in the air passage of a helicopter L-type airspeed tube, the implementation method of which is as follows: S1. Construct a pneumatic air path using metal tubing, connect the pneumatic air path to the air data computer, and install the metal probe sensor in the total pressure air path and static pressure air path. The specific steps are as follows: S101. Construct a pneumatic tube using metal tubing and connect the pneumatic tube to the digital ground of the air data computer. S102. Based on the air velocity pipe air path, the metal probe sensor is installed at the rear end of the drain hole of the main pressure air path and the static pressure air path and at the center of the cross section of each air path.

[0026] In this embodiment, as Figure 2 As shown, a metal pipe is used to construct the air velocity tube path, and it is connected to the DGND of the air data computer to ensure the normal operation of the subsequent metal probe sensor. like Figure 3 As shown, metal probe sensors are installed in the total pressure and static pressure gas paths. The metal probe sensors are installed at the rear end of the drain hole of each gas path and must be installed at the center of the cross-section of each gas path.

[0027] S2. Connect the metal probe sensor to the atmospheric data computer, and use the metal probe sensor and metal pipeline to obtain the pull-down resistance formed by rainwater. The specific steps are as follows: S201. Connect the metal probe sensor wire to the signal acquisition circuit of the atmospheric data computer. S202. Using the distance between the metal probe sensor and the metal pipe and the resistivity of rainwater, the pull-down resistance formed by rainwater between the metal probe sensor and the metal pipe is calculated.

[0028] In this embodiment, the metal probe sensor leads out wires and is connected to the signal acquisition circuit of the atmospheric data computer. The total pressure and static pressure pipeline water accumulation detection circuits are completely identical and are integrated into the signal acquisition circuit of the atmospheric data computer. Based on a pitot tube with a cross-sectional diameter of 5mm and a radius of 2.5mm, and after water accumulation, the distance between the metal probe sensor and the metal pipe is 2.5mm. Given the resistivity of rainwater is 2600... The resistance between the metal probe sensor and the metal pipe is calculated using the following expression: ; in, This indicates the pull-down resistor formed by rainwater. This indicates the distance between the metal probe sensor and the metal conduit. This indicates the resistivity of rainwater.

[0029] S3. Based on the pull-down resistor formed by rainwater, the signal acquisition circuit of the atmospheric data computer is used to detect water accumulation anomalies and obtain the detection results of water accumulation anomalies in the pitot tube air path. The specific steps are as follows: S301. Based on the pull-down resistor formed by rainwater, the signal acquisition circuit of the atmospheric data computer is used to detect abnormal water accumulation. In response to water accumulation in the air path of the air speed tube, the PNP power transistor in the water accumulation detection circuit is used to collect the water accumulation signal, and the water accumulation signal is used to drive the relay to form a fault alarm circuit loop. S302. Based on the fault alarm circuit loop, a visual alarm signal is emitted by lighting up the fault alarm light, and the optocoupler is stopped from working. The optocoupler output terminal level containing the fault signal is output through the optocoupler output terminal. S303. In response to the normal airflow path of the airspeed tube, the metal probe sensor is opened from the metal tube. The PNP power transistor in the signal acquisition circuit is pulled up to the preset level through the pull-up resistor. The optocoupler is then put into normal operation. The optocoupler output terminal level containing the fault-free signal is output. S304. The atmospheric data computer collects the output level of the optocoupler, identifies the water accumulation information of the total pressure air path and static pressure air path, and combines it with the visual alarm signal to obtain the abnormal detection result of water accumulation in the air speed tube.

[0030] In this embodiment, as Figure 4 As shown, the signal acquisition circuit includes: a first water accumulation detection circuit and a second water accumulation detection circuit; The first water accumulation detection circuit is used to detect static pressure air path and includes: resistor R1, resistor R2, resistor R3, relay K1, diode V1, PNP power transistor Q1, fault alarm light LED1 and optocoupler K2. The base of the PNP power transistor Q1 is connected to the first metal probe sensor wire and one end of resistor R3; the emitter of the PNP power transistor Q1 is connected to the ground pin of relay K1 and the anode of diode V1; the other end of resistor R3 is connected to the cathode of diode V1, the power supply pin of relay K1, one end of resistor R1, and DC15V; the other end of resistor R1 is connected to the common terminal of relay K1; the normally open contact of relay K1 is connected to the anode of fault alarm LED1; and the normally closed contact of relay K1 is connected to pin 1 of optocoupler K2. The drain of the PNP power transistor Q1 is connected to the negative terminal of the fault alarm light LED1, pin 2 and pin 3 of the optocoupler K2, and then to digital ground; pin 4 of the optocoupler K2 is connected to one end of the resistor R2 and the optocoupler output terminal Ps_out; the other end of the resistor R2 is connected to DC 3.3V. The second water accumulation detection circuit, used to detect the main air pressure circuit, includes: resistor R4, resistor R5, resistor R6, relay K3, diode V2, PNP power transistor Q2, fault alarm light LED2, and optocoupler K4. The base of the PNP power transistor Q2 is connected to the second metal probe sensor wire and one end of resistor R6; the emitter of the PNP power transistor Q2 is connected to the ground pin of relay K3 and the anode of diode V2; the other end of resistor R6 is connected to the cathode of diode V2, the power supply pin of relay K3, one end of resistor R5, and DC15V; the other end of resistor R5 is connected to the common terminal of relay K3; the normally open contact of relay K3 is connected to the anode of fault alarm LED2; and the normally closed contact of relay K3 is connected to pin 1 of optocoupler K4. The drain of the PNP power transistor Q2 is connected to the negative terminal of the fault alarm light LED2, pin 2 of the optocoupler K4, and pin 3 of the optocoupler K2, and is connected to digital ground; pin 4 of the optocoupler K4 is connected to one end of the resistor R4 and the optocoupler output terminal Ps_out; the other end of the resistor R4 is connected to DC 3.3V.

[0031] In this embodiment, as Figure 5 As shown, the signal acquisition circuit of the atmospheric data computer is used to detect water accumulation anomalies. When water accumulates in the air path, the calculated value of 650 is formed between the metal probe sensor and the metal pipeline through rainwater. The pull-down resistor is used in the water accumulation detection circuit, which collects the water accumulation signal through a PNP power transistor Q1 or Q2. The metal pipe level is "0" (DGND), and the signal is transmitted through a 650Ω circuit. The pull-down resistor pulls the base (b) of the transistor down to "0" (DGND) level, which can normally drive the emitter (c) and drain (e) of transistor Q1 or Q2 to conduct, further driving relay K1 or K3 to work. The fault alarm circuit forms a loop, and LED1 or LED2 fault alarm light illuminates. The pilot can be notified of water ingress into the pitot tube and take emergency measures through the fault alarm light. At the same time, optocoupler K2 or K4 stops working, and the signal level of the optocoupler output terminal Ps_out or Pt_out jumps from "0" (DGND) to "1" (3.3V). The air data computer collects the Ps_out or Pt_out signal level to identify whether there is water accumulation in the static pressure / total pressure air path in real time and reports the respective fault status. The pilot can check whether the water accumulation line is at total pressure or static pressure and further analyze the availability of atmospheric parameters. When the air path is normal and there is no water accumulation, the metal probe sensor is open-circuited with the metal pipeline. The PNP power transistor of the water accumulation detection circuit is pulled up to 15V through the pull-up resistor R3 or R6, and cannot drive the transistor Q1 or Q2 and the relay K1 or K3. The fault alarm circuit does not form a loop, and the fault alarm LED1 or LED2 is off. At this time, the optocoupler K2 or K4 is working normally, and the signal level of the optocoupler output terminal Ps_out or Pt_out is "0" (DGND). The air data computer identifies that there is no water accumulation in the static pressure air path or the total pressure air path by collecting the Ps_out or Pt_out signal level, and reports their respective normal status, thus obtaining the abnormal detection result of water accumulation in the air path of the air speed tube.

[0032] In this embodiment, based on the principle of water accumulation in the airspeed tube, the present invention relates to a method for detecting abnormal water accumulation in the air passage of an L-type airspeed tube for helicopters. After water accumulates in the air passage of the airspeed tube, the air data computer can automatically detect fault information through periodic BIT, and report relevant fault information using the air data computer to remind the pilot that the current atmospheric parameters (indicating airspeed, air pressure, altitude, etc.) are distorted and must be handled according to the emergency procedure to avoid flight accidents and ensure the safety of helicopter flight. The L-type pitot tube design technology is mature and the manufacturing process is stable. The present invention provides a method for detecting abnormal water accumulation in the air passage of a helicopter L-type pitot tube. This method can be integrated into the design and will not cause problems such as large size and weight to the pitot tube and the air data computer.

Claims

1. A method for detecting abnormal water accumulation in the air passage of a helicopter L-type pitot tube, characterized in that, Includes the following steps: S1. Construct an airspeed pipeline using metal tubing, connect the airspeed pipeline to the air data computer, and install the metal probe sensor in the main pressure pipeline and static pressure pipeline. S2. Connect the metal probe sensor to the atmospheric data computer, and use the metal probe sensor and metal pipeline to obtain the pull-down resistance formed by rainwater. S3. Based on the pull-down resistor formed by rainwater, the signal acquisition circuit of the atmospheric data computer is used to detect water accumulation anomalies and obtain the detection results of water accumulation anomalies in the airflow path of the airspeed tube.

2. The method for detecting abnormal water accumulation in the air passage of a helicopter L-type pitot tube according to claim 1, characterized in that, S1 includes the following steps: S101. Construct a pneumatic tube using metal tubing and connect the pneumatic tube to the digital ground of the air data computer. S102. Based on the air velocity pipe air path, the metal probe sensor is installed at the rear end of the drain hole of the main pressure air path and the static pressure air path and at the center of the cross section of each air path.

3. The method for detecting abnormal water accumulation in the air passage of a helicopter L-type pitot tube according to claim 1, characterized in that, S2 includes the following steps: S201. Connect the metal probe sensor wire to the signal acquisition circuit of the atmospheric data computer. S202. Using the distance between the metal probe sensor and the metal pipe and the resistivity of rainwater, the pull-down resistance formed by rainwater between the metal probe sensor and the metal pipe is calculated.

4. The method for detecting abnormal water accumulation in the air passage of a helicopter L-type pitot tube according to claim 3, characterized in that, The calculation expression for the pull-down resistor formed by the rainwater is as follows: in, This indicates the pull-down resistor formed by rainwater. This indicates the distance between the metal probe sensor and the metal conduit. This indicates the resistivity of rainwater.

5. The method for detecting abnormal water accumulation in the air passage of a helicopter L-type pitot tube according to claim 1, characterized in that, S3 includes the following steps: S301. Based on the pull-down resistor formed by rainwater, the signal acquisition circuit of the atmospheric data computer is used to detect abnormal water accumulation. In response to water accumulation in the air path of the air speed tube, the PNP power transistor in the water accumulation detection circuit is used to collect the water accumulation signal, and the water accumulation signal is used to drive the relay to form a fault alarm circuit loop. S302. Based on the fault alarm circuit loop, a visual alarm signal is emitted by lighting up the fault alarm light, and the optocoupler is stopped from working. The optocoupler output terminal level containing the fault signal is output through the optocoupler output terminal. S303. In response to the normal airflow path of the airspeed tube, the metal probe sensor is opened from the metal tube. The PNP power transistor in the signal acquisition circuit is pulled up to the preset level through the pull-up resistor. The optocoupler is then put into normal operation. The optocoupler output terminal level containing the fault-free signal is output. S304. The atmospheric data computer collects the output level of the optocoupler, identifies the water accumulation information of the total pressure air path and static pressure air path, and combines it with the visual alarm signal to obtain the abnormal detection result of water accumulation in the air speed tube.

6. The method for detecting abnormal water accumulation in the air passage of a helicopter L-type pitot tube according to claim 5, characterized in that, The signal acquisition circuit includes: a first water accumulation detection circuit and a second water accumulation detection circuit; The first water accumulation detection circuit is used to detect static pressure air path and includes: resistor R1, resistor R2, resistor R3, relay K1, diode V1, PNP power transistor Q1, fault alarm light LED1 and optocoupler K2. The base of the PNP power transistor Q1 is connected to the first metal probe sensor wire and one end of resistor R3; the emitter of the PNP power transistor Q1 is connected to the ground pin of relay K1 and the anode of diode V1; the other end of resistor R3 is connected to the cathode of diode V1, the power supply pin of relay K1, one end of resistor R1, and DC15V; the other end of resistor R1 is connected to the common terminal of relay K1; the normally open contact of relay K1 is connected to the anode of fault alarm LED1; and the normally closed contact of relay K1 is connected to pin 1 of optocoupler K2. The drain of the PNP power transistor Q1 is connected to the negative terminal of the fault alarm light LED1, pin 2 and pin 3 of the optocoupler K2, and then to digital ground; pin 4 of the optocoupler K2 is connected to one end of the resistor R2 and the optocoupler output terminal Ps_out; the other end of the resistor R2 is connected to DC 3.3V.

7. The method for detecting abnormal water accumulation in the air passage of a helicopter L-type pitot tube according to claim 6, characterized in that, The second water accumulation detection circuit, used to detect the main air pressure circuit, includes: resistor R4, resistor R5, resistor R6, relay K3, diode V2, PNP power transistor Q2, fault alarm light LED2, and optocoupler K4. The base of the PNP power transistor Q2 is connected to the second metal probe sensor wire and one end of resistor R6; the emitter of the PNP power transistor Q2 is connected to the ground pin of relay K3 and the anode of diode V2; the other end of resistor R6 is connected to the cathode of diode V2, the power supply pin of relay K3, one end of resistor R5, and DC15V; the other end of resistor R5 is connected to the common terminal of relay K3; the normally open contact of relay K3 is connected to the anode of fault alarm LED2; and the normally closed contact of relay K3 is connected to pin 1 of optocoupler K4. The drain of the PNP power transistor Q2 is connected to the negative terminal of the fault alarm light LED2, pin 2 of the optocoupler K4, and pin 3 of the optocoupler K2, and is connected to digital ground; pin 4 of the optocoupler K4 is connected to one end of the resistor R4 and the optocoupler output terminal Ps_out; the other end of the resistor R4 is connected to DC 3.3V.

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