A brake control method for aircraft anti-skid failure

Abstract

The present invention provides a brake control method for an aircraft anti-skid failure, belonging to the technical field of aircraft wheel brakes. The method comprises: a brake controller determining whether an aborted takeoff brake is in operation; determining whether the anti-skid function has failed; comparing the main wheel deceleration with the maximum deceleration of the aborted takeoff brake or the maximum deceleration of the non-aborted takeoff brake based on the runway type and whether the braking result is an aborted takeoff, to determine whether the main wheel has entered a deep skid state; determining the brake pressure output after the anti-skid function fails and performing a high-speed braking operation based on the runway type and the takeoff braking state; determining whether the anti-skid function should be exited; determining the brake pressure after the anti-skid function is exited and performing a low-speed braking operation. The maximum deceleration of the aborted takeoff brake is introduced into the anti-skid function, and by comparing the wheel deceleration with the maximum decelerations of different modes, the wheel is prevented from entering a deep skid or even locking, thereby improving the safety of aircraft braking.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft wheel brakes, and in particular relates to a brake control method for aircraft anti-skid failure. Background Art

[0002] The wheel brake system is one of the most important systems on an aircraft, playing a crucial role during takeoff and landing. During an aircraft's abort braking process, the wheel brake system's anti-skid function controls the braking pressure on the wheels, fully utilizing the runway's engagement to decelerate the aircraft and prevent wheel lock.

[0003] However, a common shortcoming of current aircraft wheel brake systems is that they can fail to fully release pressure in the event of a sudden runway surface change, potentially leading to wheel lock. While the wheel brake system's anti-skid function fails, it warns the pilot of the failure, but does not control the applied brake pressure. Continuously applying high brake pressure can easily lead to wheel lock or even a tire blowout, compromising the aircraft's deceleration safety and ability. Furthermore, applying low brake pressure can affect the braking efficiency of other wheels on the landing gear, increasing braking time and distance. Summary of the Invention

[0004] In order to solve the problem in the prior art that the failure of the anti-skid function of the wheel brake system can easily cause wheel locking or even tire blowout, or affect the braking efficiency of other wheels on the same landing gear, thereby increasing braking time and braking distance, the present invention proposes a brake control method for aircraft anti-skid failure. The technical solution is as follows:

[0005] A brake control method for an aircraft anti-skid fault, comprising:

[0006] Step 1: The runway module determines the runway type;

[0007] Step 2: The brake controller determines whether it is a takeoff abort brake;

[0008] Step 3: The brake controller determines whether the anti-skid function has failed;

[0009] Step 4: The brake controller compares the main wheel deceleration with the maximum deceleration of the aborted takeoff brake or the maximum deceleration of the non-aborted takeoff brake according to the runway type and whether the result is an aborted takeoff brake, to determine whether the main wheel has entered a deep skid state;

[0010] Step 5: The brake controller determines the brake pressure output after the anti-skid failure according to the runway type and the takeoff brake status, and performs a high-speed braking operation according to the brake pressure output after the anti-skid failure;

[0011] Step 6: The brake controller determines whether to exit the anti-skid function;

[0012] Step 7: The brake controller determines the brake pressure after the anti-skid function is exited, and performs a low-speed braking operation according to the brake pressure after the anti-skid function is exited.

[0013] In step 1, the runway module determines whether the runway type is a dry runway, a wet runway, or an icy runway according to the runway surface condition.

[0014] Among them, in step 2, the brake controller receives the gear position information of the automatic brake selection switch. If the gear position information indicates that the automatic brake selection switch gear is the RTO gear, the brake controller determines that it is in the aborted takeoff braking state; otherwise, the brake controller determines that it is not the aborted takeoff braking state.

[0015] In step 3, the brake controller determines that the anti-skid function has failed when any of the following conditions are met:

[0016] The wheel speed sensor is open circuit;

[0017] The wheel speed sensor is short-circuited;

[0018] The detection value of the left / right wheel speed sensor is outside the speed detection range.

[0019] Among them, in step 4, the main engine wheel deceleration is detected by a speed sensor.

[0020] Among them, in step 5, the brake controller determines the brake pressure output after the anti-skid fails according to the current pedal displacement.

[0021] Among them, in step five, the pedal displacement is detected by a pedal displacement sensor.

[0022] Among them, in step 6, if the aircraft speed is less than or equal to the anti-skid speed exit value, the anti-skid function is exited and step 7 is executed; if the aircraft speed is greater than the anti-skid speed entry value, step 2 is executed.

[0023] Among them, the anti-skid speed exit value is 20km / h, and the anti-skid speed entry value is 30km / h.

[0024] The beneficial effects of the present invention are:

[0025] The anti-skid function introduces the maximum deceleration of aborted takeoff braking. By comparing the wheel deceleration with the maximum deceleration in different modes, the wheels are prevented from entering deep skidding or even locking, thereby improving the safety of aircraft braking. After the aircraft anti-skid fails, the maximum brake pressure in different operating conditions such as on different runways and aborted takeoff braking is controlled, as well as the linear relationship between different brake commands and brake pressures. This prevents the wheels from entering deep skidding or even locking, thereby improving the safety of the aircraft under anti-skid control failure.

[0026] The present invention loads runway information, and the brake controller matches the runway information to determine the runway type, and determines the brake for aborted takeoff and the brake for non-aborted takeoff. According to different working conditions, the brake system outputs the maximum brake pressure, thereby improving the braking capability. When the anti-skid function does not fail, the maximum deceleration and real-time deceleration of the wheels are controlled to prevent the aircraft from deep skidding or even tire blowout, thereby improving the safety of the brake system. When the anti-skid function fails, the corresponding relationship between the pedal displacement and the brake pressure is adjusted, and the pedal displacement and the brake pressure are linearly output. At the same time, the brake pressure corresponding to the maximum position of the pedal displacement during an aborted takeoff is the brake pressure corresponding to the maximum deceleration of the aborted takeoff, and the brake pressure corresponding to the maximum position of the pedal displacement during a non-aborted takeoff is the brake pressure corresponding to the maximum deceleration of the non-aborted takeoff, thereby avoiding runway excursion caused by the failure of the anti-skid function during an aborted takeoff, improving the braking efficiency by about 5%, shortening the braking distance, and improving the safety of the brake system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention provides a flow chart of a brake control method for an aircraft anti-skid fault. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below through specific implementation methods and drawings.

[0029] See also Figure 1 The present invention provides a brake control method for an aircraft anti-skid fault, the method comprising the following steps:

[0030] Step 1: The runway module determines the runway type;

[0031] When determining the runway type, the runway module receives the runway surface status and determines whether it is a dry runway, a wet runway, or an icy runway.

[0032] Specifically, the runway module receives the runway surface status and matches it with the dry runway, wet runway and icy runway in the runway module database to determine whether it is a dry runway, a wet runway or an icy runway. The brake controller receives the runway type sent by the runway module.

[0033] Step 2: The brake controller determines whether it is a takeoff abort brake;

[0034] When determining whether it is an aborted takeoff brake, the brake controller receives the gear position information of the automatic brake selection switch. If the automatic brake selection switch gear is the RTO gear, the brake controller determines that it is an aborted takeoff brake; otherwise, it determines that it is not an aborted takeoff brake.

[0035] Step 3: The brake controller determines whether the anti-skid function has failed;

[0036] The brake controller determines that anti-skid failure occurs when any of the following conditions are met:

[0037] The wheel speed sensor is open circuit;

[0038] The wheel speed sensor is short-circuited;

[0039] The detection value of the left / right wheel speed sensor is not within the speed detection range (for example, the speed detection range can be 0-300 km / h);

[0040] Otherwise, the brake controller determines that anti-skid is effective.

[0041] Step 4: The brake controller determines whether the main wheels have entered a deep skid state based on the runway type and whether the takeoff braking was aborted:

[0042] In one implementation, the brake controller can determine whether the main wheel has entered a deep slip state by combining the main wheel deceleration detected by the speed sensor. The specific process is as follows:

[0043] 1) When the runway type is dry and the brake controller determines that the aircraft is braking for an aborted takeoff, it determines whether the main wheel deceleration meets a first preset requirement. If so, the brake controller determines that the wheels have entered a deep skid state and releases the brake pressure to zero. If not, normal anti-skid operation continues.

[0044] The first preset requirement is: a dt -a w ≤k (1)

[0045] Where a dt The maximum deceleration of the main wheels during a dry runway aborted takeoff braking; a w is the main wheel deceleration; k is the main wheel deep slip threshold.

[0046] 2) When the runway type is dry and the brake controller determines that the aircraft is braking for a non-aborted takeoff, the brake controller determines whether the main wheel deceleration meets a second preset requirement. If so, the brake controller determines that the wheels have entered a deep skid state and releases the brake pressure to the wheel contact pressure. If not, the anti-skid operation continues.

[0047] The second preset requirement is: a dl -a w ≤k (2)

[0048] Where a dl The maximum braking deceleration of the main wheels for a dry runway non-aborted takeoff; a w is the main wheel deceleration; k is the main wheel deep slip threshold.

[0049] 3) If the runway type is wet and the brake controller determines that the aircraft is braking for an aborted takeoff, it determines whether the main wheel deceleration meets a third preset requirement. If so, the brake controller determines that the wheels have entered a deep skid state and releases the brake pressure to zero. If not, normal anti-skid operation continues.

[0050] The third preset requirement is: a wt -a w ≤k (3)

[0051] Where a wt The maximum deceleration of the main wheels during a wet runway aborted takeoff braking; a w is the main wheel deceleration; k is the main wheel deep slip threshold.

[0052] 4) When the runway type is wet and the brake controller determines that the aircraft is braking for a non-aborted takeoff, it determines whether the main wheel deceleration meets a fourth preset requirement. If so, the brake controller determines that the wheels have entered a deep skid state and releases the brake pressure to the wheel contact pressure. If not, normal anti-skid operation continues.

[0053] The fourth preset requirement is: a wl -a w ≤k (4)

[0054] Where, α wl The maximum braking deceleration of the main wheels for a wet runway non-aborted takeoff; a w is the main wheel deceleration; k is the main wheel deep slip threshold.

[0055] 5) If the runway type is ice and the brake controller determines that the aircraft is braking for an aborted takeoff, it determines whether the main wheel deceleration meets the fifth preset requirement. If so, the brake controller determines that the wheels have entered a deep skid state and releases the brake pressure to zero. If not, normal anti-skid operation continues.

[0056] The fifth preset requirement is: a it -a w ≤k (5)

[0057] Where a it The maximum deceleration of the main wheels when braking for an aborted takeoff on an ice runway; a w is the main wheel deceleration; k is the main wheel deep slip threshold.

[0058] 6) When the runway type is ice and braking is being performed for a non-aborted takeoff, the system determines whether the main wheel deceleration meets a sixth preset requirement. If so, the brake controller determines that the wheels have entered a deep skid state and releases the brake pressure to the wheel contact pressure. If not, anti-skid operations continue.

[0059] The sixth preset requirement is: a il -a w ≤k (6)

[0060] Where a il The maximum deceleration of the main wheels for non-aborted takeoff on ice runway; a w is the main wheel deceleration; k is the main wheel deep slip threshold.

[0061] The wheel contact pressure in the present invention refers to the critical point where the wheel piston just contacts the brake device and the wheel does not generate braking torque. When the wheel slips deeply, releasing the braking pressure to the wheel contact pressure can reduce the time required for pressure to rise during continued braking and improve braking efficiency.

[0062] For example, the maximum deceleration of the main wheels during a dry runway aborted takeoff braking is a dt The maximum braking deceleration of the main wheels on a dry runway non-aborted takeoff is 4.2m / s^2. dl 4.0m / s^2; the maximum deceleration of the main wheels during a wet runway aborted takeoff braking a wt The maximum braking deceleration of the main wheels for a wet runway non-aborted takeoff is 2.8m / s^2. wt 2.5m / s^2; the maximum deceleration of the main wheels when braking on an ice runway during aborted takeoff is a it The maximum braking deceleration of the main wheels for non-aborted takeoff on ice runways is 2.1m / s^2. il The main engine wheel deep slip threshold value k is 0.2, and the wheel contact pressure is 2 MPa.

[0063] Step 5: The brake controller determines the brake pressure output after the anti-skid function fails, and performs a high-speed braking operation according to the brake pressure output after the anti-skid function fails.

[0064] In this step, the brake controller receives the pedal displacement signal detected by the pedal displacement sensor, and determines the brake pressure output after the anti-skid function fails according to the current pedal displacement.

[0065] 1) When the runway type is dry and the brake controller determines that the aircraft is in the aborted takeoff braking state, the relationship between the pedal displacement L and the brake pressure P1 output after anti-skid failure is as follows:

[0066] When 0≤L≤10, P1=0;

[0067] When 10<L≤60, P1=K1×L+C1;

[0068] When 60<L≤90, P1=K2×L+C2;

[0069] When 90<L≤105, P1=P dt .

[0070] Among them, P dt is the brake pressure corresponding to the maximum deceleration of the main wheels during a dry runway non-aborted takeoff, L is the pedal displacement, ranging from 0 to 100; P1 is the brake pressure output after anti-skid failure, K1 is the first conversion gain of pedal displacement corresponding to brake pressure, K2 is the second conversion gain of pedal displacement corresponding to brake pressure, C1 is the first conversion constant of pedal displacement corresponding to brake pressure, and C2 is the second conversion constant of pedal displacement corresponding to brake pressure.

[0071] 2) When the runway type is dry and the brake controller determines that the aircraft is in the non-aborted takeoff braking state, the relationship between the pedal displacement L and the brake pressure P1 output after anti-skid failure is as follows:

[0072] When 0≤L≤10, P1=0;

[0073] When 10<L≤60, P1=K3×L;

[0074] When 60<L≤90, P1=K4×L;

[0075] When 90<L≤105, P1=P d1 .

[0076] Among them, P dl is the brake pressure corresponding to the maximum deceleration of the main wheels during a dry runway non-aborted takeoff, L is the pedal displacement, ranging from 0 to 100; P1 is the brake pressure output after anti-skid failure, K3 is the third conversion gain of pedal displacement corresponding to brake pressure, K4 is the fourth conversion gain of pedal displacement corresponding to brake pressure, C3 is the third conversion constant of pedal displacement corresponding to brake pressure, and C4 is the fourth conversion constant of pedal displacement corresponding to brake pressure.

[0077] 3) When the runway type is wet and the brake controller determines that the aircraft is in the aborted takeoff braking state, the relationship between the pedal displacement L and the brake pressure P1 output after anti-skid failure is as follows:

[0078] When 0≤L≤10, P1=0;

[0079] When 10<L≤90, P1=K5×L+C6;

[0080] When 90<L≤105, P1=P wt .

[0081] Among them, P wt is the brake pressure corresponding to the maximum deceleration of the main wheels during a wet runway aborted takeoff, L is the pedal displacement, and the range is [0, 100]. P1 is the brake pressure output after anti-skid failure, K5 is the fifth conversion gain of the pedal displacement corresponding to the brake pressure, and C6 is the sixth conversion constant of the pedal displacement corresponding to the brake pressure.

[0082] 4) When the runway type is wet and the brake controller determines that the aircraft is in the non-aborted takeoff braking state, the relationship between the pedal displacement L and the brake pressure P1 output after anti-skid failure is as follows:

[0083] When 0≤L≤10, P1=0;

[0084] When 10<L≤90, P1=K6×L+C7;

[0085] When 90<L≤105, P1=P wl .

[0086] Among them, P wl is the brake pressure corresponding to the maximum deceleration of the main wheels during a wet runway non-aborted takeoff, L is the pedal displacement, ranging from 0 to 100; P1 is the brake pressure output after anti-skid failure, K6 is the sixth conversion gain of the pedal displacement corresponding to the brake pressure, and C7 is the seventh conversion constant of the pedal displacement corresponding to the brake pressure.

[0087] 5) When the runway type is an ice runway and the brake controller determines that the aircraft is in the aborted takeoff braking state, the relationship between the pedal displacement L and the brake pressure P1 output after the anti-skid failure is as follows:

[0088] When 0≤L≤10, P1=0;

[0089] When 10<L≤90, P1=K7×L+C8;

[0090] When 90<L≤105, P1=P it .

[0091] Among them, P it is the brake pressure corresponding to the maximum deceleration of the main wheels for an aborted takeoff on an icy runway, L is the pedal displacement, ranging from [0, 100]; P1 is the brake pressure output after anti-skid failure, K7 is the seventh conversion gain of the pedal displacement corresponding to the brake pressure, and C8 is the eighth conversion constant of the pedal displacement corresponding to the brake pressure.

[0092] 6) When the runway type is an ice runway and the brake controller determines that the aircraft is in a non-aborted takeoff braking state, the relationship between the pedal displacement L and the brake pressure P1 output after anti-skid failure is as follows:

[0093] When 0≤L≤10, P1=0;

[0094] When 10<L≤90, P1=K8×L;

[0095] When 90<L≤105, P1=P il .

[0096] Wherein, Pil is the brake pressure corresponding to the maximum deceleration of the main wheels for a non-aborted takeoff on an icy runway, L is the pedal displacement, ranging from [0, 100]; P1 is the brake pressure output after anti-skid failure, and K8 is the eighth conversion gain of the brake pressure corresponding to the pedal displacement.

[0097] For example, the maximum deceleration of the main wheels during dry runway aborted takeoff braking corresponds to the braking pressure P dt The maximum deceleration of the main wheel during dry runway non-aborted takeoff braking corresponds to the braking pressure P dl The maximum deceleration of the main wheel during a wet runway aborted takeoff braking corresponds to the braking pressure P wt The maximum deceleration of the main wheel during a wet runway non-aborted takeoff braking corresponds to the braking pressure P wl The maximum deceleration of the main engine wheel when taking off on an ice runway is 7.6 MPa, and the corresponding brake pressure is P il The maximum deceleration of the main engine wheel during non-aborted takeoff on ice runway corresponds to the braking pressure P il The first conversion gain K1 of the pedal displacement corresponding to the brake pressure is 0.1, the second conversion gain K2 of the pedal displacement corresponding to the brake pressure is 1 / 6, the third conversion gain K3 of the pedal displacement corresponding to the brake pressure is 0.08, the fourth conversion gain K4 of the pedal displacement corresponding to the brake pressure is 0.15, the fifth conversion gain K5 of the pedal displacement corresponding to the brake pressure is 0.1, the sixth conversion gain K6 of the pedal displacement corresponding to the brake pressure is 0.095, the seventh conversion gain K7 of the pedal displacement corresponding to the brake pressure is 0.075, and the eighth conversion gain K8 of the pedal displacement corresponding to the brake pressure is 0.0525, the first conversion constant C1 of pedal displacement corresponding to brake pressure is -1, the second conversion constant C2 of pedal displacement corresponding to brake pressure is -5, the third conversion constant C3 of pedal displacement corresponding to brake pressure is -0.8, the fourth conversion constant C4 of pedal displacement corresponding to brake pressure is -5, the fifth conversion constant C5 of pedal displacement corresponding to brake pressure is -1, the sixth conversion constant C6 of pedal displacement corresponding to brake pressure is -0.95, the seventh conversion constant C7 of pedal displacement corresponding to brake pressure is -0.75, and the eighth conversion constant C8 of pedal displacement corresponding to brake pressure is -0.525.

[0098] Step 6: The brake controller determines whether to exit the anti-skid function;

[0099] Determine whether to exit anti-skid. If the aircraft speed is less than or equal to the anti-skid speed exit value, exit the anti-skid function and execute step 7; if the aircraft speed is greater than the anti-skid speed entry value, execute step 2.

[0100] For example, the anti-skid speed exit value is 20 km / h, and the anti-skid speed entry value is 30 km / h.

[0101] Step 7: The brake controller determines the brake pressure after the anti-skid function is exited, and performs a low-speed braking operation according to the brake pressure after the anti-skid function is exited;

[0102] The relationship between the pedal displacement L and the brake pressure P2 after the anti-skid function is exited is as follows:

[0103] When 0≤L≤10, P=0;

[0104] When 10<L≤50, P=K9×L+C9;

[0105] When 50<L≤70, P=K 10 ×L+C 10 ;

[0106] When 70<L≤90, P=K 11 ×L+C 11 ;

[0107] When 90<L≤105, P=P max .

[0108] Where L is the pedal displacement, ranging from [0, 100]; P2 is the brake pressure after the anti-skid function is exited; K9 is the ninth conversion gain of the pedal displacement corresponding to the brake pressure, K 10 K is the tenth conversion gain of pedal displacement to brake pressure, 11 is the eleventh conversion gain of pedal displacement corresponding to brake pressure, C8 is the eighth conversion constant of pedal displacement corresponding to brake pressure, C9 is the ninth conversion constant of pedal displacement corresponding to brake pressure, and C 10 P is the tenth conversion constant corresponding to pedal displacement and brake pressure, max It is the maximum brake pressure of the wheel brake system.

[0109] For example, the ninth conversion gain K9 of pedal displacement corresponding to brake pressure is 0.2, and the tenth conversion gain K 10 =0.3, pedal displacement corresponds to brake pressure eleventh conversion gain K 11 is 0.35, the eighth conversion constant C8 of pedal displacement corresponding to brake pressure is -2, the ninth conversion constant C9 of pedal displacement corresponding to brake pressure is -7, and the tenth conversion constant C 10 is -10.5, the maximum brake pressure of the wheel brake system Pmax It is 21MPa.

[0110] The above merely describes the embodiments of the present invention, and while the description is relatively specific and detailed, it should not be construed as limiting the scope of the invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the scope of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Furthermore, any portions not described in detail herein are conventional techniques.

Claims

1. A brake control method for aircraft anti-skid failure, characterized in that: include: Step 1: The runway module determines the runway type; Step 2: The brake controller determines whether it is a takeoff abort brake; Step 3: The brake controller determines whether the anti-skid function has failed; Step 4: The brake controller compares the main wheel deceleration with the maximum deceleration of the aborted takeoff brake or the maximum deceleration of the non-aborted takeoff brake according to the runway type and whether the result is an aborted takeoff brake, to determine whether the main wheel has entered a deep skid state; Step 5: The brake controller determines the brake pressure output after the anti-skid failure according to the runway type and the takeoff brake status, and performs a high-speed braking operation according to the brake pressure output after the anti-skid failure; Step 6: The brake controller determines whether to exit the anti-skid function; Step 7: The brake controller determines the brake pressure after the anti-skid function is exited, and performs a low-speed braking operation according to the brake pressure after the anti-skid function is exited.

2. The method according to claim 1, characterized in that In step 1, the runway module determines whether the runway type is a dry runway, a wet runway, or an icy runway according to the runway surface condition.

3. The method according to claim 1, characterized in that In step 2, the brake controller receives the gear position information of the automatic brake selection switch. If the gear position information indicates that the automatic brake selection switch is in the RTO gear position, the brake controller determines that it is in the aborted takeoff braking state; otherwise, the brake controller determines that it is not the aborted takeoff braking state.

4. The method according to claim 1, wherein In step 3, the brake controller determines that the anti-skid function has failed when any of the following conditions are met: The wheel speed sensor is open circuit; The wheel speed sensor is short-circuited; The detection value of the left / right wheel speed sensor is outside the speed detection range.

5. The method according to claim 1, characterized in that In step 4, the main wheel deceleration is detected by the speed sensor.

6. The method according to claim 1, characterized in that In step five, the brake controller determines the brake pressure to be output after the anti-skid function fails based on the current pedal displacement.

7. The method according to claim 6, characterized in that In step five, the pedal displacement is detected by the pedal displacement sensor.

8. The method according to claim 1, characterized in that In step 6, if the aircraft speed is less than or equal to the anti-skid speed exit value, the anti-skid function is exited and step 7 is executed; if the aircraft speed is greater than the anti-skid speed entry value, step 2 is executed.

9. The method according to claim 8, characterized in that The anti-skid speed exit value is 20km / h, and the anti-skid speed entry value is 30km / h.

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