A method for detecting pressure of aircraft wheel brake system and preventing tire blowout

Abstract

A method for detecting pressure in an aircraft wheel brake system and preventing tire blowouts. The method determines whether a pressure closed loop exists and the error range between the actual brake pressure and the brake pressure command is determined based on the pressure deviation of different pedal displacement sensors, brake controllers, servo valves, and pressure sensors to determine whether the brake pressure of the wheel brake system is normal. This achieves the purpose of detecting pressure anomalies and residual pressure in the wheel brake system, improves the accuracy of judging abnormal brake pressure in the wheel brake system, and increases the fault detection rate of the brake control system by 5%. Based on the determined residual pressure, the residual pressure is eliminated, avoiding the problem of tire blowout caused by aircraft tire disengagement due to residual pressure braking, improving the safety of the aircraft brake system, and increasing the safety of the brake control system to 1.9E-11. The present invention does not require improvement of the existing wheel brake system, reducing the difficulty and detection cost of implementing fault detection of the wheel brake system.

Description

Technical Field

[0001] The present invention relates to the field of aircraft brakes, and in particular to a method for detecting the pressure of an aircraft wheel brake system and preventing tire blowout. Background Art

[0002] The wheel brake system is one of the most important systems in an aircraft, playing a crucial role in takeoff and landing. It primarily brakes the aircraft by controlling the opening and closing of the shutoff valve and the output of the corresponding brake pressure by the servo valve.

[0003] Patent publication number CN 114088378 A discloses a method for detecting aircraft wheel brake channel faults. This method uses the brake command signal value, brake voltage signal value, wheel speed signal value, and actual output brake pressure to identify brake channel faults caused by abnormal brake circuit output, mechanical failure of the switching valve, mechanical failure of the hydraulic fuse, and mechanical sticking of the brake control valve during braking. However, this invention fails to independently determine whether a pressure closed loop exists, fails to consider the impact of the accuracy of various devices on pressure detection, and fails to consider measures to eliminate residual pressure to prevent tire blowouts.

[0004] Patent publication number CN 114162105 A discloses a method for warning residual pressure in aircraft brake systems. This invention correlates brake commands with expected brake pressure and issues a residual pressure warning based on the calculated average brake pressure deviation, thus achieving a comprehensive residual pressure warning function for aircraft brake systems. However, this invention fails to independently determine whether a pressure loop exists, fails to consider the impact of the accuracy of various devices on pressure detection, and fails to consider measures to eliminate residual pressure and prevent tire blowouts when it exists.

[0005] Currently, the main method for detecting brake pressure is as follows: during the self-test phase of the wheel brake system, the brake controller outputs a brake pressure command signal to control the servo valve drive, which is the self-test excitation signal. The servo valve is controlled to output brake pressure, which is then collected by a pressure sensor and the actual brake pressure is sent to the brake controller. The brake controller compares the obtained brake pressure value with the brake pressure command to determine whether the brake pressure is normal. When comparing the actual brake pressure and the brake pressure command, the changes in the pressure deviation value caused by the pressure closed loop and the pressure deviation range of each system are not taken into account, resulting in a false alarm of a pressure fault when the pressure detection is normal. If the servo valve becomes stuck, the servo valve will output abnormal brake pressure, causing the wheel to dislodge or even blow out. There is no corresponding solution for this situation.

[0006] In the prior art, the wheel brake system pressure deviation does not take into account the pressure deviation and delay of the system itself, and does not provide an effective processing method when the brake residual pressure is detected. Summary of the Invention

[0007] In order to overcome the shortcomings of the existing technology that do not fully consider the pressure deviation and delay during the operation of the wheel brake system, as well as the tire blowout caused by the residual brake pressure, the present invention proposes a method for detecting the pressure of the aircraft wheel brake system and preventing the tire blowout.

[0008] The specific process of the present invention is:

[0009] Step 1: Determine whether there is pressure closed-loop control:

[0010] If the brake controller has a pressure closed loop, go to step 2; if the brake controller does not have a pressure closed loop, go to step 5.

[0011] The specific process of judging whether pressure closed-loop control is available is:

[0012] The brake controller receives the actual brake pressure P detected by the pressure sensor d , the brake controller outputs the brake command pressure P c The pressure closed-loop control refers to whether the brake command pressure is calibrated according to the actual brake pressure detected.

[0013] When the brake controller calibrates the brake command pressure according to the actual brake pressure, the brake controller has a pressure closed loop; otherwise, the brake controller has no pressure closed loop.

[0014] The pressure closed-loop control refers to a control relationship in which pressure, as a controlled output, returns to the input end as a control and exerts a control influence on the input end.

[0015] Step 2: Determine whether it is abnormal pressure detection or residual pressure detection:

[0016] When it is determined that there is a pressure closed loop, the brake controller determines whether pressure abnormality detection or residual pressure detection is performed.

[0017] The specific process is:

[0018] The brake controller is based on the brake command pressure P c Contact pressure P with the brake disc t It is determined whether to perform pressure abnormality detection or residual pressure detection. c ≤Brake disc contact pressure P t When the brake command pressure P c >Brake disc contact pressure P t When the pressure is abnormal, go to step 3 to detect the abnormal pressure.

[0019] Step 3: Determine whether the brake pressure is normal when there is a pressure closed loop:

[0020] Use formula (1) to determine whether the brake pressure is normal when the brake controller has a pressure closed loop:

[0021] |P d -P c |≤k1*P d (1)

[0022] Where, P c is the brake command pressure; P d is the actual brake pressure; k1 is the pressure sensor accuracy.

[0023] If the actual brake pressure P d If the brake controller does not satisfy formula (1) in three consecutive control cycles, the brake controller determines that the brake pressure is abnormal when the pressure loop is closed; if the actual brake pressure P d The formula (1) is not satisfied for two consecutive control cycles, and the actual brake pressure P in the third control cycle is d If formula (1) is satisfied, the brake controller determines that the brake pressure is normal when the pressure loop is closed; if the actual brake pressure P of the previous control cycle of the current control cycle is d The actual brake pressure P in the current control cycle does not satisfy formula (1). d If formula (1) is satisfied, the brake pressure is judged to be normal when the pressure loop is closed; if the actual brake pressure P d When formula (1) is satisfied for three consecutive control cycles, the brake controller determines that the brake pressure is normal when the pressure loop is closed.

[0024] Step 4: Determine whether there is residual pressure when there is a pressure closed loop:

[0025] The brake controller determines whether there is residual pressure according to the actual brake pressure and the brake disc contact pressure using formula (2):

[0026] P d >(1+k1)*P t (2)

[0027] Where, P d is the actual brake pressure; P t is the brake disc contact pressure; k1 is the pressure sensor accuracy.

[0028] If the actual brake pressure P d If formula (2) is satisfied for three consecutive control cycles, the brake controller determines that residual pressure exists; otherwise, the brake controller determines that residual pressure does not exist.

[0029] When there is residual pressure in the brake controller, execute step 9; when there is no residual pressure in the brake controller, execute step 11.

[0030] Step 5: Determine whether to perform pressure anomaly detection or residual pressure detection when there is no pressure closed loop:

[0031] The brake controller is based on the brake command pressure P c Contact pressure P with the brake disc t Determine whether to perform pressure anomaly detection or residual pressure detection when there is no pressure closed loop.

[0032] If the brake command pressure P c ≤Brake disc contact pressure P t When the brake controller determines to perform residual pressure detection, execute step 8; if the brake pressure command P c >Brake disc contact pressure P t When the brake controller determines that a pressure abnormality detection is performed, the process goes to step 6.

[0033] Step 6: Calculate the brake pressure deviation range when there is no pressure closed loop:

[0034] The brake controller is based on the brake command pressure P c and actual brake pressure P d , calculate the pressure deviation using formula (3):

[0035] ΔP=P c *(k2+k3+k5)+P d (k1+k4) (3)

[0036] Where ΔP is the pressure deviation; k2 is the pedal displacement sensor accuracy; k3 is the brake controller pedal displacement interface accuracy; k4 is the brake controller pressure interface accuracy; k1 is the pressure sensor accuracy; and k5 is the servo valve accuracy.

[0037] Step 7: Determine whether the brake pressure is normal when there is no pressure closed loop:

[0038] The brake control controller is controlled by the actual brake pressure P d and brake command pressure P c Determine whether the brake pressure is normal when there is no pressure closed loop. The brake controller determines whether the brake pressure is normal when there is no pressure closed loop using formula (4):

[0039] |P d -P c |≤ΔP (4)

[0040] Where, P c is the brake command pressure; P d is the actual brake pressure.

[0041] If the actual brake pressure P dIf formula (4) is not satisfied for three consecutive control cycles, the brake controller determines that the brake pressure is abnormal when there is no pressure closed loop.

[0042] If the actual brake pressure P d The actual brake pressure P in the third control cycle does not satisfy the formula (4) for two consecutive control cycles. d When the brake controller determines that the brake pressure is normal when there is no pressure closed loop, the brake pressure in the previous control cycle is normal. d The actual brake pressure P in the current control cycle does not satisfy formula (4). d If formula (4) is satisfied, the brake pressure is normal when there is no pressure closed loop. d If formula (4) is satisfied for three consecutive control cycles, it is determined that the braking force is normal in the pressure-free closed loop.

[0043] Step 8: The brake controller determines whether there is residual pressure when there is no pressure closed loop;

[0044] The brake controller determines whether there is residual pressure in the pressure-free closed loop according to the actual brake pressure and the brake disc contact pressure using formula (5):

[0045] P d >(1+k1+k4)*P t (5)

[0046] Where, P d is the actual brake pressure; P t is the brake disc contact pressure; k1 is the pressure sensor accuracy; k4 is the brake controller pressure interface accuracy.

[0047] If the actual brake pressure P d If formula (5) is satisfied for three consecutive control cycles, the brake controller determines that there is residual pressure when there is no pressure closed loop; otherwise, the brake controller determines that there is no residual pressure when there is no pressure closed loop.

[0048] When the brake controller determines that there is residual pressure when there is no pressure closed loop, execute step 9; if the brake controller determines that there is no residual pressure when there is no pressure closed loop, repeat steps 1 to 7 and perform residual pressure judgment again.

[0049] Step 9: Determine whether to activate residual pressure elimination:

[0050] The brake controller receives the aircraft speed sent by the aircraft. If the aircraft speed is ≤ the residual pressure elimination speed threshold and the residual pressure exists when the pressure loop is closed in step 4, or the residual pressure exists when there is no pressure closed in step 8, the brake controller activates the residual pressure elimination function. Otherwise, the brake controller does not activate the brake pressure abnormality elimination function.

[0051] Step 10: Eliminate residual pressure in the brake system:

[0052] When step 9 determines that residual pressure elimination is activated, the brake controller outputs a step signal from 0MPa to 10MPa for 100ms, and then repeats a square wave signal from 10MPa to 0MPa for 100ms five times to eliminate residual pressure.

[0053] After the residual pressure is eliminated, return to step 4 or step 8 to determine whether there is still residual pressure. If there is still residual pressure, the brake controller will issue a residual pressure alarm; otherwise, if there is no residual pressure, the brake controller will not issue a residual pressure alarm.

[0054] Step 11: The brake controller issues an abnormal pressure alarm:

[0055] When the pressure is abnormal when step 3 determines that the pressure is closed, or when step 7 determines that the pressure is abnormal when there is no pressure closed, the brake controller issues a brake pressure abnormality alarm; conversely, if the pressure is normal in both steps 3 and 7, the brake controller does not issue a brake pressure abnormality alarm.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The present invention determines whether there is a pressure closed loop and the error range between the actual brake pressure and the brake pressure command is determined based on the pressure deviation of different pedal displacement sensors, brake controllers, servo valves, and pressure sensors to determine whether the brake pressure of the wheel brake system is normal, thereby achieving the purpose of detecting pressure anomalies and residual pressure of the wheel brake system, improving the accuracy of judging abnormal brake pressure of the wheel brake system, and improving the fault detection rate of the brake control system by 5%. According to the determined residual pressure, the residual pressure is eliminated, avoiding the problem of tire blowout caused by aircraft tire derailment due to residual pressure braking, improving the safety of the aircraft brake system, and improving the safety of the brake control system to 1.9E-11. Conventional aircraft brake system pressure detection methods cannot distinguish between tests with or without a pressure closed loop, have low accuracy, low safety, and a single detection method, which has defects.

[0058] The aircraft wheel brake system fault detection method is based on the existing brake controller, shut-off valve, servo valve and sensor of the wheel brake system, and can realize information acquisition and logical judgment. There is no need to design the hardware of the wheel brake system, so that the implementation difficulty of the wheel brake system fault detection method is low and the hardware cost is not increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a flow chart for aircraft wheel brake system pressure detection and tire blowout prevention.

[0060] Figure 2 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0061] The present invention is a method for detecting the pressure of an aircraft wheel brake system and preventing tire blowout. The aircraft wheel brake system adopts existing technology and includes a pedal displacement sensor, a brake controller, a cut-off valve, a servo valve and a pressure sensor.

[0062] The specific implementation process of this embodiment is:

[0063] Step 1: Determine whether there is pressure closed-loop control:

[0064] Pressure closed-loop control refers to a control relationship in which pressure, as the controlled output, returns to the controlled input in a certain way and exerts a control influence on the input. Specifically:

[0065] The brake controller receives the actual brake pressure P detected by the pressure sensor d , the brake controller outputs the brake command pressure P c The pressure closed-loop control refers to whether the brake command pressure is calibrated according to the actual brake pressure detected.

[0066] When the brake controller calibrates the brake command pressure according to the actual brake pressure, the brake controller has a pressure closed loop; otherwise, the brake controller has no pressure closed loop.

[0067] If the brake controller has a pressure closed loop, go to step 2; if the brake controller does not have a pressure closed loop, go to step 5.

[0068] Step 2: Determine whether it is abnormal pressure detection or residual pressure detection:

[0069] When there is a pressure closed loop, the brake controller determines whether the pressure is abnormal or the residual pressure is detected. Specifically:

[0070] The brake controller is based on the brake command pressure P c Contact pressure P with the brake disc t It is determined whether to perform pressure abnormality detection or residual pressure detection. c ≤Brake disc contact pressure P t When the brake command pressure P c >Brake disc contact pressure P t When the pressure is abnormal, go to step 3 to detect the abnormal pressure.

[0071] In this embodiment, the brake disc contact pressure P t It is 1.8MPa.

[0072] Step 3: Determine whether the brake pressure is normal when there is a pressure closed loop:

[0073] Use formula (1) to determine whether the brake pressure is normal when the brake controller has a pressure closed loop:

[0074] |P d -P c |≤k1*P d (1)

[0075] Where, P c is the brake command pressure; P d is the actual brake pressure; k1 is the pressure sensor accuracy.

[0076] If the actual brake pressure P d If the brake controller does not satisfy formula (1) in three consecutive control cycles, the brake controller determines that the brake pressure is abnormal when the pressure loop is closed; if the actual brake pressure P d The formula (1) is not satisfied for two consecutive control cycles, and the actual brake pressure P in the third control cycle is d If formula (1) is satisfied, the brake controller determines that the brake pressure is normal when the pressure loop is closed; if the actual brake pressure P of the previous control cycle of the current control cycle is d The actual brake pressure P in the current control cycle does not satisfy formula (1). d If formula (1) is satisfied, the brake pressure is judged to be normal when the pressure loop is closed; if the actual brake pressure P d When formula (1) is satisfied for three consecutive control cycles, the brake controller determines that the brake pressure is normal when the pressure loop is closed.

[0077] In this embodiment, the pressure sensor accuracy k1 is 0.5%.

[0078] Step 4: Determine whether there is residual pressure when there is a pressure closed loop:

[0079] The brake controller determines whether there is residual pressure according to the actual brake pressure and the brake disc contact pressure using formula (2):

[0080] P d >(1+k1)*P t (2)

[0081] Where, P d is the actual brake pressure; P t is the brake disc contact pressure; k1 is the pressure sensor accuracy.

[0082] If the actual brake pressure P d If formula (2) is satisfied for three consecutive control cycles, the brake controller determines that residual pressure exists; otherwise, the brake controller determines that residual pressure does not exist.

[0083] When there is residual pressure in the brake controller, execute step 9; when there is no residual pressure in the brake controller, execute step 11.

[0084] In this embodiment, the pressure sensor accuracy k1 is 0.5%; the brake disc contact pressure P t It is 1.8MPa.

[0085] Step 5: Determine whether to perform pressure anomaly detection or residual pressure detection when there is no pressure closed loop:

[0086] The brake controller is based on the brake command pressure P c Contact pressure P with the brake disc t Determine whether to perform pressure anomaly detection or residual pressure detection when there is no pressure closed loop.

[0087] Perform pressure anomaly detection or residual pressure detection.

[0088] If the brake command pressure P c ≤Brake disc contact pressure P t When the brake controller determines to perform residual pressure detection, execute step 8; if the brake pressure command P c >Brake disc contact pressure P t When the brake controller determines that a pressure abnormality detection is performed, the process goes to step 6.

[0089] In this embodiment, the brake disc contact pressure P t It is 1.8MPa.

[0090] Step 6: Calculate the brake pressure deviation range when there is no pressure closed loop:

[0091] The brake controller is based on the brake command pressure P c and actual brake pressure P d , calculate the pressure deviation using formula (3):

[0092] ΔP=P c *(k2+k3+k5)+P d (k1+k4) (3)

[0093] Where ΔP is the pressure deviation; k2 is the pedal displacement sensor accuracy; k3 is the brake controller pedal displacement interface accuracy; k4 is the brake controller pressure interface accuracy; k1 is the pressure sensor accuracy; and k5 is the servo valve accuracy.

[0094] In this embodiment, the pedal displacement sensor accuracy k2 is 1%; the pedal displacement interface accuracy k3 of the brake controller is 0.1%; the pressure interface accuracy k4 of the brake controller is 1%; the pressure sensor accuracy k1 is 0.5%; and the servo valve accuracy k5 is 1.5%.

[0095] Step 7: Determine whether the brake pressure is normal when there is no pressure closed loop:

[0096] The brake control controller is controlled by the actual brake pressure P d and brake command pressure P c Determine whether the brake pressure is normal when there is no pressure closed loop. The brake controller determines whether the brake pressure is normal when there is no pressure closed loop using formula (4):

[0097] |P d -P c |≤ΔP (4)

[0098] Where, P c is the brake command pressure; P d is the actual brake pressure.

[0099] If the actual brake pressure P d If the formula (4) is not satisfied for three consecutive control cycles, the brake controller determines that the brake pressure is abnormal when there is no pressure closed loop. If the actual brake pressure P d The actual brake pressure P in the third control cycle does not satisfy the formula (4) for two consecutive control cycles. d When the brake controller determines that the brake pressure is normal when there is no pressure closed loop, the brake pressure in the previous control cycle is normal. d The actual brake pressure P in the current control cycle does not satisfy formula (4). d If formula (4) is satisfied, the brake pressure is normal when there is no pressure closed loop. d If the formula (4) is satisfied for three consecutive control cycles, it is judged that the braking force is normal in the pressure-free closed loop.

[0100] Step 8: The brake controller determines whether there is residual pressure when there is no pressure closed loop;

[0101] The brake controller determines whether there is residual pressure in the pressure-free closed loop according to the actual brake pressure and the brake disc contact pressure using formula (5):

[0102] P d >(1+k1+k4)*P t (5)

[0103] Where, P d is the actual brake pressure; P t is the brake disc contact pressure; k1 is the pressure sensor accuracy; k4 is the brake controller pressure interface accuracy.

[0104] If the actual brake pressure P d If formula (5) is satisfied for three consecutive control cycles, the brake controller determines that there is residual pressure when there is no pressure closed loop; otherwise, the brake controller determines that there is no residual pressure when there is no pressure closed loop.

[0105] When the brake controller determines that there is residual pressure when there is no pressure closed loop, execute step 9; if the brake controller determines that there is no residual pressure when there is no pressure closed loop, repeat steps 1 to 7 and perform residual pressure judgment again.

[0106] In this embodiment, the pressure sensor accuracy k1 is 0.5%; the pressure interface accuracy k4 of the brake controller is 1%; the brake disc contact pressure P t It is 1.8MPa.

[0107] Step 9: Determine whether to activate residual pressure elimination:

[0108] The brake controller receives the aircraft speed sent by the aircraft. If the aircraft speed is ≤ the residual pressure elimination speed threshold and the residual pressure exists when the pressure loop is closed in step 4, or the residual pressure exists when there is no pressure closed in step 8, the brake controller activates the residual pressure elimination function. Otherwise, the brake controller does not activate the brake pressure abnormality elimination function.

[0109] In this embodiment, the residual pressure elimination speed threshold is 3 m / s.

[0110] Step 10: Eliminate residual pressure in the brake system:

[0111] When step 9 determines that residual pressure elimination is activated, the brake controller outputs a step signal from 0MPa to 10MPa for 100ms, and then repeats a square wave signal from 10MPa to 0MPa for 100ms five times to eliminate residual pressure.

[0112] After the residual pressure is eliminated, return to step 4 or step 8 to determine whether there is still residual pressure. If there is still residual pressure, the brake controller will issue a residual pressure alarm; otherwise, if there is no residual pressure, the brake controller will not issue a residual pressure alarm.

[0113] Step 11: The brake controller issues an abnormal pressure alarm:

[0114] When the pressure is abnormal when step 3 determines that the pressure is closed, or when step 7 determines that the pressure is abnormal when there is no pressure closed, the brake controller issues a brake pressure abnormality alarm; conversely, if the pressure is normal in both steps 3 and 7, the brake controller does not issue a brake pressure abnormality alarm.

Claims

1. A method for detecting the pressure of an aircraft wheel brake system and preventing tire blowout, characterized in that: The specific process is: Step 1: Determine whether there is pressure closed-loop control: If the brake controller has a pressure closed loop, go to step 2; if the brake controller does not have a pressure closed loop, go to step 5; Step 2: Determine whether it is abnormal pressure detection or residual pressure detection: When it is determined that there is a pressure closed loop, the brake controller determines the pressure abnormality detection or residual pressure detection; The specific process is: The brake controller is based on the brake command pressure P c Contact pressure P with the brake disc t Determine whether to perform pressure abnormality detection or residual pressure detection; when the brake command pressure P c ≤Brake disc contact pressure P t When the brake command pressure P c >Brake disc contact pressure P t When , go to step 3 to detect abnormal pressure; Step 3: Determine whether the brake pressure is normal when there is a pressure closed loop: Use formula (1) to determine whether the brake pressure is normal when the brake controller has a pressure closed loop: |P d -P c |≤k1*P d (1) Where, P c is the brake command pressure; P d is the actual brake pressure; k1 is the pressure sensor accuracy; Step 4: Determine whether there is residual pressure when there is a pressure closed loop: The brake controller determines whether there is residual pressure according to the actual brake pressure and the brake disc contact pressure using formula (2): P d >(1+k1)*P t (2) Where, P d is the actual brake pressure; P t is the brake disc contact pressure; k1 is the pressure sensor accuracy; If the actual brake pressure P d When formula (2) is satisfied for three consecutive control cycles, the brake controller determines that there is residual pressure; Otherwise, the brake controller determines that there is no residual pressure; When there is residual pressure in the brake controller, execute step 9; when there is no residual pressure in the brake controller, execute step 11; Step 5: Determine whether to perform pressure anomaly detection or residual pressure detection when there is no pressure closed loop: The brake controller is based on the brake command pressure P c Contact pressure P with the brake disc t Determine whether to perform pressure anomaly detection or residual pressure detection when there is no pressure closed loop; If the brake command pressure P c ≤Brake disc contact pressure P t When the brake controller determines to perform residual pressure detection, execute step 8; if the brake pressure command P c >Brake disc contact pressure P t When the brake controller determines that the pressure is abnormal, it performs step 6; Step 6: Calculate the brake pressure deviation range when there is no pressure closed loop: The brake controller is based on the brake command pressure P c and actual brake pressure P d , calculate the pressure deviation using formula (3): ΔP=P c *(k2+k3+k5)+P d (k1+k4) (3) Where, ΔP is the pressure deviation; k2 is the pedal displacement sensor accuracy; k3 is the brake controller pedal displacement interface accuracy; k4 is the brake controller pressure interface accuracy; k1 is the pressure sensor accuracy; k5 is the servo valve accuracy; Step 7: Determine whether the brake pressure is normal when there is no pressure closed loop: The brake control controller is controlled by the actual brake pressure P d and brake command pressure P c Determine whether the brake pressure is normal when there is no pressure closed loop; the brake controller determines whether the brake pressure is normal when there is no pressure closed loop using formula (4): |P d -P c |≤ΔP (4) Where, P c is the brake command pressure; P d is the actual brake pressure; Step 8: The brake controller determines whether there is residual pressure when there is no pressure closed loop: The brake controller determines whether there is residual pressure in the pressure-free closed loop according to the actual brake pressure and the brake disc contact pressure using formula (5): P d >(1+k1+k4)*P t (5) Where, P d is the actual brake pressure; P t is the brake disc contact pressure; k1 is the pressure sensor accuracy; k4 is the brake controller pressure interface accuracy; If the actual brake pressure P d If formula (5) is satisfied for three consecutive control cycles, the brake controller determines that there is residual pressure when there is no pressure closed loop; otherwise, the brake controller determines that there is no residual pressure when there is no pressure closed loop; When the brake controller determines that there is residual pressure when there is no pressure closed loop, step 9 is executed; if the brake controller determines that there is no residual pressure when there is no pressure closed loop, steps 1 to 7 are repeated to determine the residual pressure again; Step 9: Determine whether to activate residual pressure elimination: The brake controller receives the aircraft speed sent by the aircraft. If the aircraft speed is less than or equal to the residual pressure elimination speed threshold, and if residual pressure exists when the pressure loop is closed as determined in step 4, or if residual pressure exists when there is no pressure loop as determined in step 8, the brake controller activates residual pressure elimination. Otherwise, the brake controller does not activate brake pressure abnormality elimination. Step 10: Eliminate residual pressure in the brake system: When step 9 determines that residual pressure elimination is activated, the brake controller outputs a step signal from 0MPa to 10MPa for 100ms, and then repeats a square wave signal from 10MPa to 0MPa for 100ms five times to eliminate residual pressure. After the residual pressure is eliminated, return to step 4 or step 8 to determine whether residual pressure still exists. If residual pressure still exists, the brake controller issues a residual pressure alarm. Otherwise, if there is no residual pressure, the brake controller does not issue a residual pressure alarm. Step 11: The brake controller issues an abnormal pressure alarm: When the pressure is abnormal when step 3 determines that the pressure is closed, or when step 7 determines that the pressure is abnormal when there is no pressure closed, the brake controller issues a brake pressure abnormality alarm; conversely, if the pressure is normal in both steps 3 and 7, the brake controller does not issue a brake pressure abnormality alarm.

2. The method for detecting pressure of an aircraft wheel brake system and preventing tire blowout according to claim 1, wherein: The specific process of judging whether pressure closed-loop control is available is: The brake controller receives the actual brake pressure P detected by the pressure sensor d , the brake controller outputs the brake command pressure P c The pressure closed-loop control refers to whether the brake command pressure is calibrated according to the actual brake pressure detected; When the brake controller calibrates the brake command pressure according to the actual brake pressure, the brake controller has a pressure closed loop; otherwise, the brake controller has no pressure closed loop.

3. The method for detecting pressure of an aircraft wheel brake system and preventing tire blowout as claimed in claim 1, wherein: The pressure closed-loop control refers to a control relationship in which pressure, as a controlled output, returns to the input end as a control and exerts a control influence on the input end.

4. The method for detecting pressure of an aircraft wheel brake system and preventing tire blowout as claimed in claim 1, wherein: In step 3, if the actual brake pressure P d If the formula (1) is not satisfied in three consecutive control cycles of the brake controller, the brake controller determines that the brake pressure is abnormal when the pressure loop is closed; If the actual brake pressure P d The formula (1) is not satisfied for two consecutive control cycles, and the actual brake pressure P in the third control cycle is d If formula (1) is satisfied, the brake controller determines that the brake pressure is normal when the pressure loop is closed; If the actual brake pressure P of the previous control cycle of the current control cycle d The actual brake pressure P in the current control cycle does not satisfy formula (1). d If formula (1) is satisfied, the brake pressure is judged to be normal when the pressure loop is closed; If the actual brake pressure P d When formula (1) is satisfied for three consecutive control cycles, the brake controller determines that the brake pressure is normal when the pressure loop is closed.

5. The method for detecting pressure of an aircraft wheel brake system and preventing tire blowout as claimed in claim 1, wherein: If the actual brake pressure P d If formula (4) is not satisfied for three consecutive control cycles, the brake controller determines that the brake pressure is abnormal when there is no pressure closed loop; If the actual brake pressure P d The actual brake pressure P in the third control cycle does not satisfy the formula (4) for two consecutive control cycles. d When formula (4) is satisfied, the brake controller determines that the brake pressure is normal when there is no pressure closed loop; If the actual brake pressure P in the previous control cycle d The actual brake pressure P in the current control cycle does not satisfy formula (4). d If formula (4) is satisfied, the brake pressure is judged to be normal when there is no pressure closed loop; If the actual brake pressure P d If the formula (4) is satisfied for three consecutive control cycles, it is judged that the braking force is normal in the pressure-free closed loop.

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