Airplane brake control dynamic pressure reference and brake command global tracking matching method

Abstract

The application provides an airplane brake control dynamic pressure reference and brake instruction global tracking matching method, and belongs to the technical field of airplane brake control. t Wherein t=0, 1, 2,... represents the update number; the brake instruction tracking matching coefficient is calculated; the output brake pressure is calculated. Through the dynamic reference and the matching coefficient, the application ensures that the brake instruction is always matched with the current optimal pressure in the range of 0% to 100%, and solves the problem of small brake instruction stroke and poor controllability in the conventional method.

Description

Technical Field

[0001] This invention belongs to the field of aircraft brake control technology, specifically relating to a method for tracking and matching dynamic pressure reference and braking command across the entire range of aircraft brake control. Background Technology

[0002] The adaptive braking process of an aircraft is a dynamic matching process between braking torque and ground contact torque. When the ground contact torque is constant, a large braking material torque requires a small braking pressure, and a small braking material torque requires a large braking pressure. However, during braking, the braking material torque changes continuously with speed, temperature, etc., while the ground contact torque also changes continuously with aircraft weight, coefficient of friction, aircraft lift, etc.

[0003] For the reasons mentioned above, the dynamic pressure reference for brake control generated during the dynamic matching process of braking torque and ground torque in the adaptive braking process of an aircraft is constantly changing, while the brake command is designed from no-stroke to full-stroke, with the full-stroke being the rated value. The full-stroke is generally matched with the maximum brake pressure.

[0004] Conventional adaptive braking control methods do not fully track and match the dynamic pressure reference of aircraft braking control with the braking command. When the braking material torque is large, the controllable braking command stroke is very small, resulting in very poor maneuverability.

[0005] Conventional adaptive braking control methods have drawbacks in command matching design: they cannot track and match braking commands across the entire range based on the aircraft's dynamic pressure reference for braking control, resulting in poor braking maneuverability and low control precision. Summary of the Invention

[0006] The technical problem to be solved:

[0007] To overcome the shortcomings of existing technologies, this invention provides a method for matching a dynamic pressure reference and a full-domain braking command for aircraft braking control. By calculating the slip ratio change rate in real time, a slip ratio change rate of 0 is defined as the point where the braking torque and ground torque are balanced. The braking pressure at this point is used as the dynamic reference and continuously updated. A matching coefficient is calculated to map the full-stroke braking command to the dynamic reference pressure, achieving full-domain linear control. This invention, through the dynamic reference and matching coefficient, ensures that the braking command always matches the current optimal pressure within the range of 0% to 100%, solving the problems of short braking command stroke and poor maneuverability in conventional methods.

[0008] The technical solution of this invention is: a method for full-domain tracking and matching of dynamic pressure reference and braking command for aircraft braking control, the specific steps of which are as follows:

[0009] Real-time acquisition of aircraft speed and wheel speed, calculation of slip ratio and its rate of change;

[0010] When the rate of change of slip ratio is detected to be 0, the current brake pressure value is set as the dynamic pressure reference P. t , where t = 0, 1, 2, ... represents the update sequence number;

[0011] Calculate the braking command tracking matching coefficient k t The formula is as follows:

[0012] k t =P t / Lmax

[0013] In the formula, Lmax is the full braking command value;

[0014] Calculate the output braking pressure P out The formula is as follows:

[0015] P out =k t L

[0016] In the formula, L is the set braking command value, and the maximum value is the full braking command value Lmax.

[0017] A further technical solution of the present invention is: the formula for calculating the slip ratio is as follows:

[0018]

[0019] In the formula, v p For the speed of the aircraft, v w For wheel speed;

[0020] The formula for calculating the rate of change of slip ratio is as follows:

[0021] λ'=df(λ) / dλ.

[0022] A further technical solution of the present invention is: the dynamic pressure reference P t The initial value P0 is determined when the first braking command is applied by triggering the slip rate change rate to be equal to 0.

[0023] A further technical solution of the present invention is: the dynamic pressure reference P t Updated each time a braking command is reapplied, and the updated P t Replace the previous baseline value.

[0024] A further technical solution of the present invention is that the value range of the full-stroke braking command value Lmax is 100.

[0025] A further technical solution of the present invention is: the value range of the braking command value L is 0 to Lmax, and L is related to the output pressure P. out They exhibit a linear proportional relationship.

[0026] An aircraft braking control system, comprising:

[0027] The slip ratio calculation module is used to calculate the slip ratio and its rate of change in real time.

[0028] The dynamic benchmark generation module is used to generate a dynamic pressure benchmark when the slip ratio change rate is equal to 0.

[0029] The matching coefficient calculation module is used to calculate the brake command tracking matching coefficient based on the dynamic pressure reference and the full brake command value.

[0030] The pressure output module is used to output brake pressure based on the brake command tracking matching coefficient and the set brake command value.

[0031] A further technical solution of the present invention is that the system is integrated into the fly-by-wire anti-skid brake controller and communicates with the aircraft speed sensor, wheel speed sensor and brake actuator through a communication bus.

[0032] An aircraft equipped with the aforementioned aircraft braking control system.

[0033] A further technical solution of the present invention is: when the rate of change of slip ratio is detected to be equal to 0, the dynamic pressure reference P is forcibly triggered. t Update.

[0034] Beneficial effects

[0035] The beneficial effects of this invention are as follows: This invention determines the dynamic pressure reference P. t Calculate the dynamic pressure reference k for tracking and matching the brake command. t Calculate the output braking pressure P out This system achieves full-domain tracking and matching of dynamic pressure benchmarks and braking commands for aircraft braking control, solving the problems of poor maneuverability and low control precision of conventional braking, and significantly improving the maneuverability and control precision of aircraft adaptive braking. Specific advantages are analyzed below:

[0036] 1. By updating the dynamic pressure reference and matching coefficient in real time, the braking pressure can be linearly and steplessly adjusted across the entire range of 0% to 100%, avoiding the problems of "ineffective light pressing and excessive heavy pressing" in traditional methods, and significantly improving the driver's operating experience.

[0037] 2. Based on the trigger condition that the slip ratio change rate is equal to 0, the system can capture the balance point between the braking torque and the ground contact torque in real time and automatically adapt to complex working conditions such as sudden changes in the runway friction coefficient and the degradation of braking material performance.

[0038] 3. By precisely triggering the brakes when the slip ratio change rate is equal to 0, the braking pressure is always close to the torque balance point, reducing the slip ratio fluctuation range, maximizing the use of ground friction, and shortening the braking distance.

[0039] 4. It can be seamlessly integrated into the fly-by-wire anti-skid braking system and is compatible with the braking actuators of different aircraft types (civilian passenger planes, transport planes, etc.). Only the range of the full-stroke braking command value needs to be adjusted.

[0040] Table 1 shows the comparison data between the present invention and conventional methods.

[0041] Table 1 Comparison of data from conventional methods and the present invention.

[0042]

[0043] Note: When Lmax = 100, the conventional method in item 4 cannot achieve a pressure output greater than 10. Detailed Implementation

[0044] The embodiments described below with reference to the present invention are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0045] Existing conventional adaptive braking control methods suffer from problems such as the inability to track and match braking commands across the entire range based on the aircraft's dynamic pressure reference, resulting in poor braking maneuverability and low control accuracy. This invention proposes a method for tracking and matching aircraft braking control dynamic pressure reference with braking commands across the entire range. The specific steps are as follows:

[0046] Step 1: Determination of Dynamic Pressure Reference

[0047] During the application of the braking command, the slip ratio λ is continuously calculated according to formula (1).

[0048]

[0049] In the formula, v p For the speed of the aircraft, v w This represents the speed of the wheel.

[0050] When the rate of change of slip ratio λ' is 0, it indicates that the braking torque equals the ground contact torque, and the corresponding braking pressure is the aircraft's current pressure reference P. t The initial brake pressure reference is P0. When a brake command is subsequently applied again, the brake pressure reference is continuously updated to P1, P2, P3, and so on; the pressure reference is dynamically updated. Pressure reference P t In this context, t represents the pressure baseline update count, with values ​​of 0, 1, 2, 3, ..., and the slip ratio change rate λ' is calculated according to formula (2).

[0051] λ'=df(λ) / dλ(2)

[0052] This step determines the aircraft's current pressure reference by the slip rate change rate λ', which takes effect after the brake command is released and then reapplied.

[0053] Step 2: Braking command tracking and matching with dynamic pressure benchmark

[0054] The dynamic pressure reference k for brake command tracking is calculated using formula (3). t .

[0055] k t =P t / Lmax(3)

[0056] In the formula, Lmax is the full braking command value, which is a constant, typically taken as 100. t is the pressure reference update count, with values ​​of 0, 1, 2, 3...

[0057] This step is performed using pressure reference P. t The braking command tracking and matching dynamic pressure reference k0 is calculated from the full braking command value Lmax and remains unchanged until the braking pressure reference is P1, P2, P3... Then, k1, k2, k3... are dynamically updated and calculated using formula (2).

[0058] This step determined the dynamic pressure benchmark k for brake command tracking. t This enables the tracking and matching of braking commands with dynamic pressure benchmarks.

[0059] Step 3, brake pressure output

[0060] The output braking pressure P is calculated using formula (4). out

[0061] P out = k t L (4)

[0062] In the formula, L is the set braking command value, and the maximum value is the full braking command value Lmax.

[0063] This step enables linear control of brake pressure across the entire range of brake commands.

[0064] This invention proposes an aircraft braking control system, comprising:

[0065] The slip ratio calculation module is used to calculate the slip ratio and its rate of change in real time.

[0066] The dynamic benchmark generation module is used to generate a dynamic pressure benchmark when the slip ratio change rate is equal to 0.

[0067] The matching coefficient calculation module is used to calculate the brake command tracking matching coefficient based on the dynamic pressure reference and the full brake command value.

[0068] The pressure output module is used to output brake pressure based on the brake command tracking matching coefficient and the set brake command value.

[0069] Specifically, the system is integrated into the fly-by-wire anti-skid brake controller and communicates with the aircraft speed sensor, wheel speed sensor and brake actuator via a communication bus.

[0070] This invention proposes an aircraft equipped with the aforementioned aircraft braking control system.

[0071] When the rate of change of slip ratio is detected to be equal to 0, the dynamic pressure reference P is forcibly triggered. t Update.

[0072] The above technical solution will be further analyzed below with examples:

[0073] Example 1: A method for full-domain tracking and matching of dynamic pressure reference and braking command for aircraft braking control, the specific steps of which are as follows:

[0074] Step 1: Determination of Dynamic Pressure Reference

[0075] During the initial application of the braking command, t = 0, and the slip ratio λ is continuously calculated according to formula (1). The braking command value ranges from 0 to 100. The default braking pressure reference 10 corresponds to the braking command 100.

[0076]

[0077] In the formula, v p For the speed of the aircraft, v w This represents the speed of the wheel.

[0078] When the rate of change of slip ratio λ' is 0, it indicates that the braking torque equals the ground contact torque, and the corresponding braking pressure is the aircraft's current pressure reference P. t =P0=8, and the corresponding braking command obtained by default is 80.

[0079] This step determines the aircraft's current pressure baseline P0 = 8 using the slip ratio change rate λ', and the brake release command is 0.

[0080] Step 2: Braking command tracking and matching with dynamic pressure benchmark

[0081] The dynamic pressure reference k0 for brake command tracking is calculated using formula (3).

[0082] k t =P0 / Lmax(3)

[0083] In formula (3), Lmax = 100.

[0084] This step calculates the dynamic pressure reference k for brake command tracking and matching using the pressure reference P0 = 8 and the full brake command value Lmax = 100. t =0.08.

[0085] Step 3, brake pressure output

[0086] The output braking pressure P is calculated using formula (4). out

[0087] P out =k t L(4)

[0088] k t =0.08: When L=20, P out =1.6; when L=60, P out =4.8; when L=100, P out =8.

[0089] This embodiment achieves tracking and matching between the initial applied braking command pressure reference P0 = 8 and the full braking command value Lmax = 100. Compared to the default braking pressure reference 10 corresponding to braking command 100, where braking pressure 8 corresponds to braking command 80, the pressure reference P0 = 8 in this embodiment corresponds to the full braking command value Lmax = 100, thus improving braking operability and control accuracy.

[0090] Example 2:

[0091] Step 1: Determination of Dynamic Pressure Reference

[0092] After completing Example 1, during the process of applying the braking command again, t=1, and the slip ratio λ is calculated according to formula (1). The braking command value ranges from 0 to 100.

[0093]

[0094] In the formula, v p For the speed of the aircraft, v w This represents the speed of the wheel.

[0095] When the rate of change of slip ratio λ' is 0, it indicates that the braking torque equals the ground contact torque, and the corresponding braking pressure is the aircraft's current pressure reference P. t =P1=4.8, the corresponding braking command is 60.

[0096] This step determines the aircraft's current pressure baseline P1 = 4.8 using the slip rate change rate λ', and the brake release command is 0.

[0097] Step 2: Braking command tracking and matching with dynamic pressure benchmark

[0098] The dynamic pressure reference k1 for brake command tracking is calculated using formula (3).

[0099] k t =P1 / Lmax(3)

[0100] In formula (3), Lmax = 100.

[0101] This step calculates the dynamic pressure reference k for brake command tracking matching using the pressure reference P1 = 4.8 and the full brake command value Lmax = 100. t =0.048. k t An increase indicates that the braking torque has increased or the ground contact torque has decreased.

[0102] This step determined the dynamic pressure benchmark k for brake command tracking. t =0.048, which realizes the tracking and matching of braking commands with dynamic pressure benchmark.

[0103] Step 3, brake pressure output

[0104] The output braking pressure P is calculated using formula (4). out

[0105] P out =k t L(4)

[0106] k t =0.048. When L=20, P out =0.96; when L=60, P out =2.88; when L=100, P out =4.8.

[0107] This second embodiment achieves the tracking and matching of the pressure reference P1 = 4.8 and the full braking command value Lmax = 100 after the dynamic braking torque increases or the ground contact torque decreases.

[0108] Compared to the matching of brake pressure 4.8 and brake command 60 in Embodiment 1, the pressure reference P1 = 4.8 in Embodiment 2 corresponds to the full brake command value Lmax = 100, further improving brake operability and control precision.

[0109] In Examples 1 and 2, the dynamic pressure reference P is continuously determined. t Calculate the dynamic pressure reference k for tracking and matching the brake command. t Calculate the output braking pressure P outIt achieves full-domain tracking and matching of dynamic pressure reference and braking command for aircraft braking control, solving the problems of poor maneuverability and low control accuracy of conventional braking, and significantly improving the maneuverability and control accuracy of aircraft adaptive braking.

[0110] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for full-domain tracking and matching of dynamic pressure reference and braking command for aircraft braking control, characterized in that... The specific steps are as follows: Real-time acquisition of aircraft speed and wheel speed, calculation of slip ratio and its rate of change; When the rate of change of slip ratio is detected to be 0, the current brake pressure value is set as the dynamic pressure reference P. t , where t = 0, 1, 2, ... represents the update sequence number; Calculate the braking command tracking matching coefficient k t The formula is as follows: k t =P t / Lmax In the formula, Lmax is the full braking command value; Calculate the output braking pressure P out The formula is as follows: P out =k t L In the formula, L is the set braking command value, and the maximum value is the full braking command value Lmax.

2. The method for matching dynamic pressure reference and braking command across the entire range for aircraft braking control according to claim 1, characterized in that: The formula for calculating the slip ratio is as follows: In the formula, v p For the speed of the aircraft, v w For wheel speed; The formula for calculating the rate of change of slip ratio is as follows: λ'=df(λ) / dλ.

3. The method for matching dynamic pressure reference and braking command across the entire range for aircraft braking control according to claim 1, characterized in that: The dynamic pressure reference P t The initial value P0 is determined when the first braking command is applied by triggering the slip rate change rate to be equal to 0.

4. The method for matching dynamic pressure reference and braking command across the entire range for aircraft braking control according to claim 3, characterized in that: The dynamic pressure reference P t Updated each time a braking command is reapplied, and the updated P t Replace the previous baseline value.

5. The method for matching dynamic pressure reference and braking command across the entire range for aircraft braking control according to claim 1, characterized in that: The value range of the full-stroke braking command value Lmax is 100.

6. The method for matching dynamic pressure reference and braking command across the entire range for aircraft braking control according to claim 5, characterized in that: The braking command value L ranges from 0 to Lmax, and L is related to the output pressure P. out They exhibit a linear proportional relationship.

7. An aircraft braking control system, used to implement the aircraft braking control dynamic pressure reference and braking command full-domain tracking and matching method according to any one of claims 1-6; characterized in that, include: The slip ratio calculation module is used to calculate the slip ratio and its rate of change in real time. The dynamic benchmark generation module is used to generate a dynamic pressure benchmark when the slip ratio change rate is equal to 0. The matching coefficient calculation module is used to calculate the brake command tracking matching coefficient based on the dynamic pressure reference and the full brake command value. The pressure output module is used to output brake pressure based on the brake command tracking matching coefficient and the set brake command value.

8. The aircraft braking control system according to claim 7, characterized in that: The system is integrated into the fly-by-wire anti-skid brake controller and communicates with the aircraft speed sensor, wheel speed sensor and brake actuator via a communication bus.

9. An aircraft, characterized in that, The aircraft is equipped with the aircraft braking control system described in claim 7.

10. The aircraft according to claim 9, characterized in that: When the rate of change of slip ratio is detected to be equal to 0, the dynamic pressure reference P is forcibly triggered. t Update.

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