Anti-skid protection control method for aircraft wheel brake system

Abstract

A method for controlling anti-skid protection of an aircraft wheel brake system optimizes the anti-skid protection control logic. When the bus wheel load signal is invalid, the brake controller determines whether to apply braking based on the hard-wired wheel load. The brake controller determines whether the wheel is fully rotating based on the wheel reference speed in real time, more accurately expressing whether the wheel is rotating, preventing misjudgments caused by wheel jumps, and improving system safety. When the left and right wheel load signals are inconsistent, judgment is made based on the airspeed signal, avoiding loss of braking function due to wheel load jumps during low-speed taxiing, and improving system availability by 12%. The present invention improves anti-skid protection through the brake controller, effectively avoiding misindications of wheel loads during low-speed taxiing and complete loss of braking function due to jumps; provides judgment of bus signal validity, improving the availability of the brake system; introduces wheel speed validity judgment, improving the accuracy of anti-skid protection, and effectively improving the availability of the brake system by 12%.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft wheel brakes, in particular to an anti-skid protection control method for an aircraft wheel brake system. Background Art

[0002] An aircraft's wheel brake system is one of its most critical systems, playing a crucial role during takeoff and landing. After the aircraft touches down, the wheel brake system's anti-skid protection function activates. This function ensures that the wheels are fully rotating and at the same speed as the aircraft before applying braking pressure. This effectively protects against tire blowouts caused by insufficient wheel rotation immediately after touchdown.

[0003] Publication No. CN 114670798 A discloses a ground fault protection control method for an aircraft brake system. This invention determines the front wheel load status of the anti-skid brake control box. The determined front wheel load status or the collected left and right wheel speed signals are used to determine the aircraft's current ground position and whether to apply brake pressure. This invention does not consider the possibility of erroneous indication of the front wheel load status, which could result in insufficient wheel rotation before applying brake pressure, leading to wheel lock.

[0004] Publication No. CN105620455A discloses an aircraft brake system and its ground fault protection control method. This invention uses logic operations in an anti-skid control box and a low-speed detection unit to determine the aircraft's high and low speed status signals. The anti-skid control box collects wheel speed signals from the left and right main landing gear, processes and converts them into a reference speed voltage signal simulating the aircraft's speed, and the low-speed detection unit of the anti-skid control box indicates the aircraft's high / low speed status. This invention determines the aircraft's high and low speed status based on wheel speed, resulting in low brake availability.

[0005] At present, the anti-skid protection control logic commonly used in my country's aircraft brake system is: the brake controller receives the left and right wheel bus signals, the left and right wheel hard line signals, and when the four wheel signals are all on the ground or the left and right wheel speeds exceed If the brake controller determines that the aircraft has touched down and the wheels are fully rotated, braking can be performed. It then outputs a servo-valve control signal corresponding to the brake command signal. Otherwise, even if the pedals are depressed, the brake command output by the brake controller is 0, resulting in no braking. This prevents wheel lock caused by pedal brake commands after the aircraft has landed, when the wheels have not fully rotated. In this determination, if any of the four wheel load signals indicate an erroneous indication or a jump during low-speed taxiing, braking function is lost, resulting in reduced brake availability. Summary of the Invention

[0006] In order to solve the problem in the prior art of complete loss of braking caused by wheel load jump or erroneous indication during low-speed taxiing of the brake system, the present invention proposes an anti-skid protection control method for an aircraft wheel brake system.

[0007] The specific process of the present invention is:

[0008] Step 1: The brake controller receives bus signals and hard-wire signals:

[0009] The bus signals include the left wheel bus signal, the right wheel bus signal, the airspeed signal, the aircraft deceleration rate, and the valid judgment position of each signal. The hard line signals include the left wheel hard line signal and the right wheel hard line signal.

[0010] The valid judgment bit of the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate is 0 or 1; when the valid judgment bit of the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate is 0, the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate signal are invalid; when the valid judgment bit of the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate is 1, the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate signal are valid.

[0011] The left wheel-borne bus signal and the left wheel-borne hard-wire signal come from two different wheel-borne sensors of the left landing gear; the right wheel-borne bus signal and the right wheel-borne hard-wire signal come from two different wheel-borne sensors of the right landing gear.

[0012] The brake controller receives the left wheel-mounted hard-wire signal and the right wheel-mounted hard-wire signal from the landing gear control unit, and receives the left wheel-mounted bus signal and the right wheel-mounted bus signal sent by the data processing module through the bus.

[0013] Step 2: Determine the left wheel load signal and the right wheel load signal:

[0014] When both the left wheel bus signal and the right wheel bus signal are valid, the left wheel bus signal is the left wheel bus signal and the right wheel bus signal is the right wheel bus signal; when either the left wheel bus signal or the right wheel bus signal is invalid, the left wheel signal is the left wheel hard wire signal and the right wheel signal is the right wheel hard wire signal.

[0015] Step 3: Determine the validity of the wheel speed signal:

[0016] The brake controller receives the wheel speed signals detected by each wheel speed sensor installed on the main engine wheel, and detects open circuit fault, short circuit fault and out-of-range fault of the wheel speed sensor.

[0017] When any of the open circuit fault, short circuit fault or out-of-range fault is detected, the wheel speed signal is determined to be invalid; when no open circuit fault, short circuit fault or out-of-range fault is detected, the wheel speed signal is determined to be valid.

[0018] Step 4, calculate the wheel reference speed:

[0019] The brake controller calculates the wheel reference speed based on the wheel speed and the aircraft deceleration rate. When the wheel speed exceeds the wheel reference speed, the wheel speed is used as the wheel reference speed. When the wheel speed is less than or equal to the wheel reference speed, the wheel reference speed is reduced by the aircraft deceleration rate.

[0020] The wheel reference speed calculation formula is:

[0021]

[0022] Where V r is the wheel reference speed of the current control cycle, a is the aircraft deceleration rate, is the wheel reference speed of the previous control cycle, V w is the wheel speed.

[0023] When the wheel speed signal is invalid, the wheel speed is set to 0 and the wheel reference speed is set to 0.

[0024] When the aircraft deceleration rate signal is invalid, set the aircraft deceleration rate to 4.

[0025] When the airspeed signal is invalid, set the airspeed signal to 0.

[0026] Step 5: Methods for determining the aircraft's air / ground status include:

[0027] Ⅰ When both the left wheel load signal and the right wheel load signal are on the ground, it is determined that the aircraft's wheels have not fully started to rotate on the ground, and the time for the aircraft's wheels to not fully start to rotate on the ground is counted;

[0028] II. Determine whether the duration of the aircraft's wheels not fully spinning on the ground is greater than the wheel load duration threshold;

[0029] III. If it is determined that the timer is greater than the wheel load duration threshold, it is determined that the aircraft is in a fully rotating wheel state on the ground;

[0030] IV. When it is determined that the timer is not greater than the wheel load duration threshold, and when it is determined in real time that either the left wheel reference speed or the right wheel reference speed is less than the wheel rotation start speed threshold, it is determined that the wheels of the aircraft have not fully started to rotate on the ground;

[0031] V. When the left wheel load signal and the right wheel load signal are inconsistent, if the airspeed signal is less than the airspeed threshold, it is determined that the aircraft is on the ground and the wheels are fully rotated;

[0032] VI. When both the left wheel reference speed and the right wheel reference speed are greater than the wheel rotation speed threshold, it is determined that the aircraft's wheels have not fully started rotating on the ground, and a timer is set for the aircraft's state of insufficient wheel rotation on the ground;

[0033] VII. Determine whether the aircraft's ground wheel rotation state is greater than the speed duration threshold;

[0034] VIII. If it is determined that the timer is greater than the speed duration threshold, the aircraft is judged to be in a fully rotating wheel state on the ground;

[0035] IX. When it is determined that the timer is not greater than the speed duration threshold, the left wheel load signal and the right wheel load signal are inconsistent, and the airspeed signal is greater than or equal to the airspeed threshold, it is determined that the aircraft is on the ground and the wheels have not fully started to rotate;

[0036] Ⅹ When it is determined that both the left wheel-borne signal and the right wheel-borne signal are in the air, it is determined that the aircraft is in the air.

[0037] Step 6: Determine the brake pressure output by the brake system;

[0038] In this implementation, the anti-slip protection control strategy is executed, including:

[0039] When it is determined that the aircraft is in a fully rotating wheel state on the ground, the maximum brake pressure of the brake system is allowed to be output;

[0040] When it is determined that the aircraft is in the air or the wheels of the aircraft are not fully rotated on the ground, the brake pressure output by the brake system is 0.

[0041] At this point, the control process of the aircraft wheel brake system anti-skid protection is completed.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The present invention optimizes the traditional anti-skid protection control logic as follows: if the bus wheel load signal is invalid, such as due to a bus communication failure or transmission error, the brake controller determines whether braking can be implemented through hard-wired wheel load; at the same time, the brake controller determines in real time whether the wheel has fully started to rotate based on the wheel reference speed. Compared with using the wheel speed, this method can more accurately express whether the wheel has started to rotate, prevent misjudgment caused by wheel jump, and improve system safety by 1.2E-10; when the left and right wheel load signals are inconsistent, the airspeed signal is introduced for judgment, which has avoided the loss of braking function due to wheel load jump when the aircraft is taxiing at low speed, and improved the system availability by 12%. By adopting the anti-skid protection control method provided in the embodiment of the present invention, the anti-skid protection can be improved by only changing the control method of the brake controller without changing other hardware of the brake system. The anti-skid protection control method effectively avoids the disadvantages of false wheel load indication and complete loss of braking function caused by jumps during low-speed taxiing. At the same time, it provides a judgment on the validity of the bus signal. When the bus signal is invalid, it is judged through the hard-wire signal, thereby improving the availability of the brake system. The introduction of wheel speed validity judgment improves the accuracy of anti-skid protection and effectively improves the availability of the brake system by 12%.

[0044] In this invention, the left wheel bus signal and the left wheel hardwire signal originate from two different wheel-mounted sensors on the left landing gear, while the right wheel bus signal and the right wheel hardwire signal originate from two different wheel-mounted sensors on the right landing gear. By utilizing two different wheel-mounted sensors on the same landing gear, transmitting them via the bus and hardwire, respectively, the loss of braking function due to a single wheel-mounted sensor failure is effectively avoided, improving the availability and safety of the braking system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is the wheel load signal collection diagram of the present invention.

[0046] Figure 2 It is a schematic diagram of the technical solution of the present invention.

[0047] Figure 3 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0048] The anti-skid protection control method of this embodiment is designed for an aircraft brake system. In the aircraft brake system, the airspeed signal, the left wheel load signal, and the right wheel load signal are introduced into the brake controller via a bus, and the left wheel load signal and the right wheel load signal are introduced into the brake controller via a hard line.

[0049] Figure 2 This is a flow chart of an anti-skid protection control method for an aircraft brake system provided by an embodiment of the present invention.

[0050] Reference Figure 1 and Figure 2 As shown, the anti-skid protection control method of the aircraft brake system provided by the embodiment of the present invention may include the following steps:

[0051] Step 1: The brake controller receives bus signals and hard-wire signals:

[0052] The bus signals include the left wheel bus signal, the right wheel bus signal, the airspeed signal, the aircraft deceleration rate, and the valid judgment position of each signal. The hard line signals include the left wheel hard line signal and the right wheel hard line signal.

[0053] The valid judgment bit of the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate is 0 or 1; when the valid judgment bit of the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate is 0, the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate signal are invalid; when the valid judgment bit of the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate is 1, the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate signal are valid.

[0054] The left wheel-borne bus signal and the left wheel-borne hard-wire signal come from two different wheel-borne sensors of the left landing gear; the right wheel-borne bus signal and the right wheel-borne hard-wire signal come from two different wheel-borne sensors of the right landing gear.

[0055] The brake controller receives the left wheel-mounted hard-wire signal and the right wheel-mounted hard-wire signal from the landing gear control unit, and receives the left wheel-mounted bus signal and the right wheel-mounted bus signal sent by the data processing module through the bus.

[0056] Step 2: Determine the left wheel load signal and the right wheel load signal:

[0057] When both the left wheel bus signal and the right wheel bus signal are valid, the left wheel bus signal is the left wheel bus signal and the right wheel bus signal is the right wheel bus signal; when either the left wheel bus signal or the right wheel bus signal is invalid, the left wheel signal is the left wheel hard wire signal and the right wheel signal is the right wheel hard wire signal.

[0058] Step 3, judging the validity of the wheel speed signal;

[0059] The brake controller receives wheel speed signals from each wheel speed sensor installed on the main wheels. It detects open circuit, short circuit, and out-of-range faults in the wheel speed sensors. If any of these faults are detected, the wheel speed signal is deemed invalid. If none of these faults are detected, the wheel speed signal is deemed valid.

[0060] The detection range of the wheel speed sensor in this embodiment is 0 to 300 km / h.

[0061] Step 4, calculating the wheel reference speed;

[0062] The brake controller calculates the wheel reference speed using the wheel speed and the aircraft deceleration rate. When the wheel speed is greater than the wheel reference speed, the wheel speed is used as the wheel reference speed. When the wheel speed is less than or equal to the wheel reference speed, the wheel reference speed is reduced by the aircraft deceleration rate. The wheel reference speed calculation formula is:

[0063]

[0064] Among them, V r is the wheel reference speed of the current control cycle, a is the aircraft deceleration rate, is the wheel reference speed of the previous control cycle, V w is the wheel speed.

[0065] When the wheel speed signal is invalid, the wheel speed is set to 0 and the wheel reference speed is set to 0.

[0066] When the aircraft deceleration rate signal is invalid, set the aircraft deceleration rate to 4.

[0067] When the airspeed signal is invalid, set the airspeed signal to 0.

[0068] Step 5: Methods for determining the aircraft's air / ground status include:

[0069] Ⅰ When both the left wheel load signal and the right wheel load signal are on the ground, it is determined that the aircraft's wheels have not fully started to rotate on the ground, and the time for the aircraft's wheels to not fully start to rotate on the ground is counted;

[0070] II. Determine whether the duration of the aircraft's wheels not fully spinning on the ground is greater than the wheel load duration threshold;

[0071] III. If it is determined that the timer is greater than the wheel load duration threshold, it is determined that the aircraft is in a fully rotating wheel state on the ground;

[0072] IV. When it is determined that the timer is not greater than the wheel load duration threshold, and when it is determined in real time that either the left wheel reference speed or the right wheel reference speed is less than the wheel rotation start speed threshold, it is determined that the wheels of the aircraft have not fully started to rotate on the ground;

[0073] V. When the left wheel load signal and the right wheel load signal are inconsistent, if the airspeed signal is less than the airspeed threshold, it is determined that the aircraft is on the ground and the wheels are fully rotated;

[0074] VI. When both the left wheel reference speed and the right wheel reference speed are greater than the wheel rotation speed threshold, it is determined that the aircraft's wheels have not fully started rotating on the ground, and a timer is set for the aircraft's state of insufficient wheel rotation on the ground;

[0075] VII. Determine whether the aircraft's ground wheel rotation state is greater than the speed duration threshold;

[0076] VIII. If it is determined that the timer is greater than the speed duration threshold, the aircraft is judged to be in a fully rotating wheel state on the ground;

[0077] IX. When it is determined that the timer is not greater than the speed duration threshold, the left wheel load signal and the right wheel load signal are inconsistent, and the airspeed signal is greater than or equal to the airspeed threshold, it is determined that the aircraft is on the ground and the wheels have not fully started to rotate;

[0078] Ⅹ When it is determined that both the left wheel-borne signal and the right wheel-borne signal are in the air, it is determined that the aircraft is in the air.

[0079] In this embodiment, the speed duration threshold is 500 ms, the wheel load duration threshold is 2 s, the wheel rotation speed threshold is 50 km / h, and the airspeed threshold is 100 km / h.

[0080] The aircraft air / ground status judgment logic is shown in the table below.

[0081] Table 1

[0082]

[0083]

[0084] Step 6: Determine the brake pressure output by the brake system;

[0085] In this implementation, Figure 2 As shown, the anti-skid protection control strategy is implemented, including:

[0086] When it is determined that the aircraft is in a fully rotating wheel state on the ground, the maximum brake pressure of the brake system is allowed to be output;

[0087] When it is determined that the aircraft is in the air or the wheels of the aircraft are not fully rotated on the ground, the brake pressure output by the brake system is 0.

[0088] At this point, the control process of the aircraft wheel brake system anti-skid protection is completed.

Claims

1. A method for controlling anti-skid protection of an aircraft wheel brake system, characterized in that: The specific process is: Step 1: The brake controller receives bus signals and hard-wire signals: The bus signal includes a left wheel bus signal, a right wheel bus signal, an airspeed signal, an aircraft deceleration rate, and a valid judgment position of each signal; the hard line signal includes a left wheel hard line signal and a right wheel hard line signal; The left wheel-borne bus signal and the left wheel-borne hard-wire signal come from two different wheel-borne sensors of the left landing gear; the right wheel-borne bus signal and the right wheel-borne hard-wire signal come from two different wheel-borne sensors of the right landing gear; the brake controller receives the left wheel-borne hard-wire signal and the right wheel-borne hard-wire signal from the landing gear control unit, and receives the left wheel-borne bus signal and the right wheel-borne bus signal sent by the data processing module through the bus; Step 2: Determine the left wheel load signal and the right wheel load signal: Determine whether the left wheel signal is a left wheel bus signal or a left wheel hard wire signal, and whether the right wheel signal is a right wheel bus signal or a right wheel hard wire signal: When both the left wheel bus signal and the right wheel bus signal are valid, the left wheel bus signal is the left wheel bus signal and the right wheel bus signal is the right wheel bus signal; when either the left wheel bus signal or the right wheel bus signal is invalid, the left wheel signal is the left wheel hard wire signal and the right wheel signal is the right wheel hard wire signal; Step 3: Determine the validity of the wheel speed signal: The brake controller receives the wheel speed signals detected by each wheel speed sensor installed on the main engine wheel, and determines the validity of the wheel speed signals based on the open circuit fault, short circuit fault and out-of-range fault of the wheel speed sensor detected; Step 4, calculate the wheel reference speed: The brake controller calculates the wheel reference speed based on the wheel speed and the aircraft deceleration rate. When the wheel speed is greater than the wheel reference speed, the wheel speed is used as the wheel reference speed. When the wheel speed is less than or equal to the wheel reference speed, the wheel reference speed is reduced by the aircraft deceleration rate. When the wheel speed signal is invalid, the wheel speed is set to 0 and the wheel reference speed is set to 0; When the aircraft deceleration rate signal is invalid, set the aircraft deceleration rate to 4; When the airspeed signal is invalid, set the airspeed signal to 0; Step 5: Determine the aircraft's air / ground status: The method of determining the air / ground status of the aircraft includes: Ⅰ When both the left wheel load signal and the right wheel load signal are on the ground, it is determined that the aircraft's wheels have not fully started to rotate on the ground, and the time for the aircraft's wheels to not fully start to rotate on the ground is counted; II. Determine whether the duration of the aircraft's wheels not fully spinning on the ground is greater than the wheel load duration threshold; III. If it is determined that the timer is greater than the wheel load duration threshold, it is determined that the aircraft is in a fully rotating wheel state on the ground; IV. When it is determined that the timer is not greater than the wheel load duration threshold, and when it is determined in real time that either the left wheel reference speed or the right wheel reference speed is less than the wheel rotation start speed threshold, it is determined that the wheels of the aircraft have not fully started to rotate on the ground; V. When the left wheel load signal and the right wheel load signal are inconsistent, if the airspeed signal is less than the airspeed threshold, it is determined that the aircraft is on the ground and the wheels are fully rotated; VI. When both the left wheel reference speed and the right wheel reference speed are greater than the wheel rotation speed threshold, it is determined that the aircraft's wheels have not fully started rotating on the ground, and a timer is set for the aircraft's state of insufficient wheel rotation on the ground; VII. Determine whether the aircraft's ground wheel rotation state is greater than the speed duration threshold; VIII. If it is determined that the timer is greater than the speed duration threshold, the aircraft is judged to be in a fully rotating wheel state on the ground; IX. When it is determined that the timer is not greater than the speed duration threshold, the left wheel load signal and the right wheel load signal are inconsistent, and the airspeed signal is greater than or equal to the airspeed threshold, it is determined that the aircraft is on the ground and the wheels have not fully started to rotate; Ⅹ When it is determined that both the left wheel load signal and the right wheel load signal are in the air, the aircraft is determined to be in the air; Step 6: Determine the brake pressure output by the brake system; When it is determined that the wheels of the aircraft are fully rotated on the ground, the maximum brake pressure of the brake system is allowed to be output; when it is determined that the aircraft is in the air or the wheels of the aircraft are not fully rotated on the ground, the brake pressure output by the brake system is 0; At this point, the control process of the aircraft wheel brake system anti-skid protection is completed.

2. The anti-skid protection control method for an aircraft wheel brake system according to claim 1, characterized in that: The valid judgment bit of the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate is 0 or 1; when the valid judgment bit of the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate is 0, the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate signal are invalid; when the valid judgment bit of the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate is 1, the left wheel-borne bus signal, the right wheel-borne bus signal, the airspeed signal and the aircraft deceleration rate signal are valid.

3. The anti-skid protection control method for an aircraft wheel brake system according to claim 1, wherein: When any of the open circuit fault, short circuit fault or out-of-range fault is detected, the wheel speed signal is determined to be invalid; when no open circuit fault, short circuit fault or out-of-range fault is detected, the wheel speed signal is determined to be valid.

4. The anti-skid protection control method for an aircraft wheel brake system according to claim 1, wherein: The wheel reference speed calculation formula is: Where V r is the wheel reference speed of the current control cycle, a is the aircraft deceleration rate, is the wheel reference speed of the previous control cycle, V w is the wheel speed.

5. The anti-skid protection control method for an aircraft wheel brake system according to claim 1, wherein: The data processing module sends the bus signals received from other systems to the brake controller; the landing gear control unit sends the wheel-mounted hard-wire signals to the brake controller.

6. The anti-skid protection control method for an aircraft wheel brake system according to claim 1, wherein: The brake controller receives the left wheel-borne hard-wired signal and the right wheel-borne hard-wired signal from the landing gear control unit, and makes a comprehensive judgment based on the left wheel-borne bus signal and the right wheel-borne bus signal sent by the bus receiving data processing module; when both bus wheel loads are valid and both indicate the ground, it is judged that the aircraft is on the ground; if either the left wheel-borne bus signal or the right wheel-borne bus signal is invalid, the left wheel-borne hard-wired signal and the right wheel-borne hard-wired signal are used to judge the aircraft's air / ground status.

Images