CN114476032A

CN114476032A - Method and system for releasing brake in slipping-out stage and storage medium

Info

Publication number: CN114476032A
Application number: CN202210086840.9A
Authority: CN
Inventors: 陆伟铭; 张奇; 孙魁; 李冰; 杨弘; 王自杨
Original assignee: Commercial Aircraft Corp of China Ltd
Current assignee: Commercial Aircraft Corp of China Ltd
Priority date: 2022-01-25
Filing date: 2022-01-25
Publication date: 2022-05-13

Abstract

The brake releasing system at the sliding-out stage comprises a first logic judgment unit, a second logic judgment unit, a third logic judgment unit and a brake control unit, wherein the first logic judgment unit is used for judging whether the brake temperature reaches a first threshold value and sending a first signal when the brake temperature does not reach the first threshold value; the second logic judgment unit is used for judging whether the wheel speed of the airplane reaches a second threshold value and sending a second signal when the wheel speed does not reach the second threshold value; the third logic judgment unit is used for judging whether the pedal displacement stroke reaches a third threshold value and sending a third signal when the pedal displacement stroke does not reach the third threshold value; the brake control unit is configured to receive the automatic brake RTO gear pre-position signal, the throttle lever slow parking space signal and the pedal signal, and to receive the first, second and third signals, and is configured to transmit a release brake signal after simultaneously receiving the pre-position signal, the throttle lever slow parking space signal, the pedal signal, the first signal, the second signal and the third signal, thereby alternatively releasing the brakes of a portion of the wheels. A method of releasing the brake during the roll-out phase and a storage medium are also provided.

Description

Method and system for releasing brake in slipping-out stage and storage medium

Technical Field

The invention relates to the field of aircraft brake control, in particular to the field of release brake control.

Background

The airplane wheel braking system of the airplane is used for absorbing the huge kinetic energy generated when the airplane lands or takes off intermittently (RTO), and converting the kinetic energy into heat energy to stop the airplane. The heat of braking can adversely affect the tires, landing gear components, brake components, and structural and system components within the landing gear bay. In addition, the long-term brake state will also increase the wear to the wheel carbon disk, increase the flight cost. The good or bad of heat dispersion directly influences the braking effect of the brake disc.

The relationship between braking temperature and carbon disc wear in several typical braking systems is shown in fig. 1, wherein the abscissa represents braking temperature caused by braking heat, the ordinate represents the wear rate of the carbon disc, the solid line, the dotted line and the dotted line represent the wear curves of S, Q, T carbon discs used for braking by three braking companies, respectively, and the line P represents the temperature when the brake is over-heated. As can be known from FIG. 1, the temperature of 0-300 ℃ corresponds to a region with higher wear rate, and the brake is released at this time, which is more favorable for reducing the wear of the carbon disk; the wear rate is relatively low at the temperature of 400-.

With continued reference to FIG. 2, the abscissa represents various common operational scenarios for a particular type of aircraft and the ordinate represents the braking temperature. In each operation scene of the airplane, the stage A represents an approach-grounding stage of the airplane, and the brake temperature gradually drops until a small amount of residual temperature before grounding exists; the B stage represents the landing-sliding-in stage of the airplane, and the brake temperature is gradually increased; the C stage represents the aircraft stopping waiting stage, and the braking temperature is gradually reduced; stage D shows that the airplane is in a sliding-out stage, and the braking temperature is increased and is less than the safe flying temperature by 300 ℃; the E stage represents the stage after the aircraft takes off, the braking is not needed any more at the moment, and the braking temperature is gradually reduced.

As can be seen from fig. 2, the braking temperature in the slipping-out stage is below 300 ℃, but still has a higher temperature, and is in the temperature range where the carbon disk is most sensitive to wear, so it is necessary to design a method for releasing the brake, and the brake release is performed in the slipping-out stage according to the temperature characteristic in the slipping-out stage, so as to effectively reduce the wear of the carbon disk.

Currently, there are several ways to help the brake assembly dissipate heat or reduce the effect of brake heat on other components, including designing heat shields to protect the tires, designing fans on the wheels to speed up cooling, bleed air ventilation to reduce the temperature in the landing gear bay, and so on. In addition, a method is provided, during low-speed sliding, because the speed of an airport is limited, a brake is required to be frequently used, the kinetic energy is relatively small, all brakes are not required to be used for braking an airplane, and the idle brake can introduce air through a gap between a movable disc and a static disc to dissipate heat more quickly. The boeing applies the technology of releasing the brake during the sliding in B777, B787 and other models, namely only the front 4 brakes or the back 4 brakes work when the plane slides while stepping the brake, thus reducing the abrasion of the carbon disk and being beneficial to heat dissipation.

Chinese patent CN104417515 discloses a "selection logic based on stopping energy for releasing the taxi brakes", when at least one processor determines that the energy of at least one second brake is greater than the energy for at least one first brake, the at least one second brake is released, and the logic for releasing is judged by the energy difference of the front and rear brakes. The method does not consider the influence of temperature on the release of the brake, selects by judging and comparing the energy of the brake, and has a complex implementation process in engineering.

Disclosure of Invention

One object of the present invention is to provide a slip-out phase release brake system for releasing the brakes during the slip-out phase, reducing carbon disc wear and being targeted.

The slipping-out stage release brake system for achieving the purpose is used for releasing partial brake of the airplane wheel in the slipping-out stage and comprises a first logic judgment unit, a second logic judgment unit, a third logic judgment unit and a brake control unit, wherein the first logic judgment unit is used for judging whether the brake temperature reaches a first threshold value or not and sending a first signal when the brake temperature does not reach the first threshold value; the second logic judgment unit is used for judging whether the wheel speed of the airplane reaches a second threshold value and sending a second signal when the wheel speed does not reach the second threshold value; the third logic judgment unit is used for judging whether the pedal displacement stroke reaches a third threshold value and sending a third signal when the pedal displacement stroke does not reach the third threshold value; the brake control unit is configured to receive an automatic brake RTO gear pre-position signal, a throttle lever slow parking space signal and a pedal signal, and to receive the first signal, the second signal and the third signal, and is configured to transmit a release brake signal after simultaneously receiving the automatic brake RTO gear pre-position signal, the throttle lever slow parking space signal, the pedal signal, the first signal, the second signal and the third signal, thereby alternatively releasing the brake of a part of the wheels.

In one or more embodiments, the brake control unit is further configured to count a number of times the wheel is pedalled, and to release a modification signal when the number of pedalling times changes, the modification signal being capable of replacing the braking state of the wheel.

In one or more embodiments, the brake system for releasing in the slipping-out stage further includes a fourth logic determination unit, configured to compare brake temperatures of all the wheels, and send a priority signal to the brake control unit, so as to preferentially release the wheel with a higher brake temperature.

In one or more embodiments, the third logic determination unit is configured to issue a fourth signal when the pedal displacement stroke exceeds the third threshold, the fourth signal for transmission to the brake control unit to prevent transmission of the release brake signal.

In one or more embodiments, the brake control unit is further configured to identify a wheel position where braking is released and to issue a first blocking signal to block transmission of the brake release signal when the number of wheels located on the same side of the aircraft requiring brake release exceeds half of the total number of wheels on the same side.

In one or more embodiments, the first threshold is 300 ℃, the second threshold is 30 knots, and the third threshold is 70% of the maximum pedal displacement travel.

Another object of the present invention is to provide a method for releasing a brake during a slide-out phase, which uses the above slide-out phase release brake system, comprising the steps of:

when the braking temperature does not reach the first threshold value, a first condition is met;

a second condition is established when the wheel speed of the airplane does not reach a second threshold value;

a third condition is established when the pedal signal appears and the pedal displacement stroke does not reach a third threshold value;

a fourth condition is established when an RTO gear pre-position signal of the automatic brake appears;

a fifth condition is met when a throttle lever slow parking space signal appears;

alternatively releasing the braking of the partial wheel when the first condition, the second condition, the third condition, the fourth condition and the fifth condition are all established.

In one or more embodiments, the number of times the kick signal is changed replaces the braking state of the wheel.

In one or more embodiments, a sixth condition is established when the pedal displacement travel exceeds the third threshold, and the release of the brakes is discontinued after the sixth condition is established.

In one or more embodiments, the number of wheels released in one at a time is half the number of total wheels.

In one or more embodiments, the method preferentially releases some of the total wheels that have higher braking temperatures.

It is a further object of the invention to provide a storage medium on which a computer program is stored, the steps of the above method being performed by a processor.

According to the slipping-out stage brake releasing system, the brake control unit is used for simultaneously acquiring the RTO gear pre-position signal, the throttle lever slow parking position signal, the pedal signal, the first signal, the second signal and the third signal of the automatic brake, so that the slipping-out stage of the airplane is accurately judged, the brake of part of airplane wheels is released in the slipping-out stage, the wear rate is high in the slipping-out stage, the carbon disc can be effectively reduced in the process of releasing the brake in the slipping-out stage, and better benefits are obtained.

Drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description of the embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of wear rate of a brake carbon disc versus brake temperature.

FIG. 2 is a schematic diagram of a brake temperature range of a common operation scenario of a certain type of airplane.

FIG. 3 is a slide out phase release brake function architecture diagram.

FIG. 4 is a logic diagram for the operation of the slide-out phase release braking system.

Description of the reference numerals

10 first logic judgment unit

20 second logic judgment unit

30 third logic judgment unit

40 fourth logic judgment unit

50 automatic braking RTO gear pre-position signal

60 throttle lever slow parking stall signal

70 foot pedal signal

80 brake control unit

100 front wheel

150 wheel

160 brake control valve

200 rear wheel

Detailed Description

The present invention is further described in the following description with reference to specific embodiments and the accompanying drawings, wherein the details are set forth in order to provide a thorough understanding of the present invention, but it is apparent that the present invention can be embodied in many other forms different from those described herein, and it will be readily appreciated by those skilled in the art that the present invention can be implemented in many different forms without departing from the spirit and scope of the invention. It is noted that these and other figures which follow are merely exemplary and not drawn to scale and should not be considered as limiting the scope of the invention as it is actually claimed.

Also, the present application uses specific words to describe embodiments of the application. Reference throughout this specification to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic described in connection with at least one embodiment of the present application is included in at least one embodiment of the present application. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, some features, structures, or characteristics of one or more embodiments of the present application may be combined as appropriate.

The application discloses a slipping-out stage release brake system for releasing a part of brakes in a slipping-out stage, so that the brake is released in the slipping-out stage with a high wear rate, the abrasion of a carbon disc is reduced, and better benefits are obtained.

It should be noted that the following description uses terms such as "first", "second", etc. to define components, which are used only for convenience of distinguishing corresponding components, and the terms have no special meaning if not stated otherwise, and therefore, should not be construed as limiting the scope of protection of the present application.

Referring to fig. 3 and 4, the slipping-out phase release Brake system includes a first logic determining Unit 10, a second logic determining Unit 20, a third logic determining Unit 30, and a Brake Control Unit 80 (BCU), where the first logic determining Unit 10 is configured to determine whether a Brake temperature reaches a first threshold value and send a first signal when the Brake temperature does not reach the first threshold value; the second logic judgment unit 20 is used for judging whether the wheel speed of the airplane reaches a second threshold value and sending a second signal when the wheel speed does not reach the second threshold value; the third logic judgment unit 30 is configured to judge whether the pedal displacement stroke reaches a third threshold value and send a third signal when the pedal displacement stroke does not reach the third threshold value; the brake control unit 80 is configured to receive the automatic brake RTO (interrupted flight) gear pilot signal 50, the throttle lever slow parking space signal 60, and the pedal signal 70, and to receive the first signal, the second signal, and the third signal, and is configured to transmit a brake release signal after simultaneously receiving the automatic brake RTO gear pilot signal 50, the throttle lever slow parking space signal 60, the pedal signal 70, the first signal, the second signal, and the third signal, so as to alternatively release the brake of a portion of the wheel 150.

Specifically, the automatic brake RTO gear indicates that the aircraft is in a preparation takeoff stage and is located in the automatic brake knob, and if the aircraft needs to be abnormal during takeoff and running before takeoff, the automatic brake RTO gear plays a role in emergently providing interruption takeoff for the unit, so that the automatic brake RTO gear can clearly distinguish a slide-in stage and a slide-out stage of the aircraft. Since the automatic brake RTO gear preset signal is only selected when the aircraft is in the roll-off phase when the aircraft is ready to take off, the automatic brake RTO gear preset signal 50 is one of important information for judging the roll-off phase.

As shown in fig. 2, the braking temperature can also clearly distinguish between the in-and out-of-flight phases of the aircraft. In the aircraft model to which the present disclosure relates, the dispatch temperature of the aircraft is 300 ℃, and the aircraft is not allowed to take off when the brake temperature exceeds 300 ℃, so the ambient temperature in the roll-off phase is close to 300 ℃. And in the sliding-in stage, after the aircraft is in the B stage and is stopped when landing, the temperature range is 400-600 ℃, so that the brake temperature can be used as one of important information for judging whether the aircraft is in the sliding-out stage.

Therefore, the first logic judgment unit 10 judges whether the brake temperature reaches the first threshold value and sends out the first signal when the brake temperature does not reach the first threshold value. The first threshold value is preferably 300 ℃, and when the brake temperature is lower than 300 ℃, the first threshold value can be used as one of important information for judging that the airplane is in the slipping-out stage.

It should be noted that the first threshold is not fixed at 300 ℃, and in other aircraft models, the dispatch temperature of the aircraft may have other values. Thus, the first threshold value is selected by the crew as appropriate for the particular aircraft model and is not limited to the illustrated embodiment of the present disclosure.

The brake temperature may be acquired in real time by a temperature sensor located on the wheel 150.

Continuing with FIG. 4, the activation of the foot pedal signal 70 indicates that the pilot is taking steps on the foot pedal and that the aircraft is in need of braking, and therefore that the plurality of wheels 150 of the front wheel 100 and the rear wheel 200 are in a braked state. The brake control unit 80 receives the pedal signal 70, is isolated from the automatic braking function, and uses the pilot's operation of the pedal as a precondition for activating the release of the braking command, so as to ensure the safety of the system.

The pedal has another displacement stroke for transmitting signals. When an emergency occurs, such as an event of invading the runway, and the pilot considers that the deceleration rate is not enough, the pilot usually steps on the brake suddenly, and the judgment of the pedal displacement travel occurs at the moment. When the displacement stroke of the pedals is too large, the pilot takes obvious reaction to the pedals, so that the possibility of the occurrence of the risks is not eliminated, the sliding-out and brake releasing functions are released at the moment, and the airplane can be continuously braked until dangerous contact is ensured.

Based thereon, the third logic determining unit 30 is configured to issue a fourth signal when the pedal displacement stroke exceeds the third threshold, the fourth signal for transmission to the brake control unit 80 to prevent transmission of the release brake signal; and when the pedal displacement stroke does not reach a third threshold value, a third signal is sent out and is used as one of judgment conditions for allowing the brake to be released.

Preferably, the third threshold is 70% of the maximum pedal displacement stroke. The linear displacement sensor exists in the pedal, the detection value of the linear displacement sensor has a maximum pedal displacement stroke of 100%, and when the detection value of the linear displacement sensor is 70%, the pedal displacement is severe, and emergency occurs with high probability. Thus, a pedal displacement stroke of more than 70% indicates a greater pilot response and the possibility of an emergency risk exists, where the brakes should not be released.

The wheel speed signal is the key to distinguish the slide-out phase, the slide-in phase and the landing braking phase, wherein the slide-out phase is located at the phase C shown in fig. 2, and the slide-in phase and the landing braking phase are both located at the phase B shown in fig. 2, wherein the landing braking phase is located at the front part of the phase B where the temperature rises sharply, and the slide-in phase is located at the rear part of the phase B where the temperature is milder. The wheel speed signal is higher during the landing and braking phase, and the wheel speed during the slip-out phase is around the low speed range of 30 knots (Kts). The second threshold is preferably 30 knots (Kts). When the wheel speed of the airplane does not reach the second threshold value, the wheel speed of the airplane is indicated to be in a low-speed interval, and the judgment condition is one of important judgment conditions for judging that the airplane is in a slip-out stage.

It should be noted that the second threshold is not limited to 30 sections, and those skilled in the art can understand that the requirements of different models for the wheel speed are different, so that the value of the second threshold is selected by those skilled in the art according to the actual situation of the aircraft.

Similarly, there is an important condition for throttle lever slow stall signal 60 to distinguish whether the aircraft is in the roll-off phase or the landing braking phase. Since the accelerator is in a reverse thrust position in the landing and braking stage, and the accelerator rod is in a slow parking position in the sliding-in stage and the sliding-out stage, the existence of the accelerator rod slow parking position signal 60 is the key for distinguishing the sliding-out stage and the landing and braking stage, thereby preventing the airplane from losing partial braking in the landing and braking stage and ensuring the braking safety.

In one embodiment, the brake control unit 80 is further configured to count the number of pedal signals 70 and release a modification signal when the number of pedal signals 70 changes, the modification signal being capable of replacing the braking state of the front or rear wheels.

Specifically, each pedal signal represents a braking operation, the brake control unit 80 can determine the number of times the pedal is braked during coasting, has a braking signal when the pedal is completely released, and switches the front wheel 100 or the rear wheel 200 when the pedal is released.

For example, when the number of times of pedaling signals is N, the four-wheel brake after release is selected at the moment; the pilot steps on the brake again with the foot, and the number of times of the pedal signal is counted as N +1, will release the brake signal and transmit to the front wheel this moment, release the front four-wheel brake and replace the state of back four-wheel.

As shown in fig. 4, the five function activation condition signals must be satisfied simultaneously, and if any one of the signals does not satisfy the condition, the function must be inhibited, so as to ensure the safety of the braking system. In addition, when an emergency occurs and the pilot thinks that the deceleration rate is not enough, the pilot can increase the pedal stroke by stepping on the brake suddenly and remove the brake releasing function when the pedal stroke reaches a certain threshold value.

In a preferred embodiment, the wheels 150 are released one at a time in half the number of total wheels for better results.

As shown in fig. 3, the airplane model includes 8 wheels 150 in total, namely a front wheel 100 and a rear wheel 200, and in general, each of the front wheel 100 and the rear wheel 200 includes 4 wheels 150 which are symmetric with each other two by two. In other embodiments, other aircraft models may also have 4-wheel or 12-wheel configurations. The number of partial wheels released one at a time is half the number of full wheels.

Such as the embodiment shown in fig. 3, the number of wheels in the front wheel 100 or the rear wheel 200 is 4 per release. The number of single releases is 6 wheels if the aircraft has 12 wheels, or 2 wheels if the aircraft has 4 wheels.

When the brake is released, 4 wheels of the front wheel 100 or the rear wheel 200 can be released in a unified manner; any 4 wheels 150 of the 8

wheels

100 and 200 may be released, and the 4 wheels with higher temperature may be preferentially released.

In the embodiment shown in fig. 3, since 8 independent brake control valves 160 correspond to 8 independent brake actuators, each brake control valve 160 can receive an independent control signal to release the wheel brake, so as to achieve any release of any wheel brake.

In one embodiment, the brake release system during the roll-out phase further comprises a fourth logic determining unit 40 for comparing the brake temperatures of all wheels 150 and sending a priority signal to the brake control unit 80 to preferentially release the wheel 150 with higher brake temperature. According to the judgment of the brake temperature, certain brakes with higher temperature are released each time, so that the whole heat dissipation of the brake system is more favorable.

On the basis of the above embodiment, the brake control unit 80 is configured to identify the position of the wheels that are released from braking, and to send a first blocking signal when the number of wheels that need to be released from braking on the same side of the aircraft exceeds half of the total number of wheels on the same side of the aircraft, so as to block the transmission of the brake release signal, release the brake release function, and prevent the moving path of the aircraft from deviating.

As shown in fig. 3, when the four wheels 150 on the left side are released at the same time, the first identification procedure is started, the transmission of the brake release signal is prevented, the brake release function is released, and the deviation of the moving path of the airplane is avoided; or when more than 3 wheels on the left side are released together, the situation exceeds half of the number of all wheels on the left side, at this time, the first identification program is started, the brake control unit 80 sends out a first blocking signal, the transmission of the brake releasing signal is blocked, and the brake releasing function is released.

In conjunction with the above description of a slip-out phase release brake system, a method of releasing a brake using the above described slip-out phase release brake system may also be understood.

The method comprises the following steps: when the braking temperature does not reach the first threshold value, a first condition is met; a second condition is established when the wheel speed of the airplane does not reach a second threshold value; a third condition is established when the pedal signal appears and the pedal displacement stroke does not reach a third threshold value; a fourth condition is established when an RTO gear pre-position signal of the automatic brake appears; a fifth condition is met when a throttle lever slow parking space signal appears; when the first condition, the second condition, the third condition, the fourth condition, and the fifth condition are all established, the brake of the partial wheel 150 is released alternatively.

In general, a pilot operates a brake pedal, the brake control unit 80 receives a pedal displacement signal and outputs a command to the brake control valve 160, and the brake control valve 160 controls the braking action of the wheels to realize braking. On the premise that the above five conditions are satisfied, the brake control unit 80 outputs a brake release signal to the brake control valve 160, thereby alternatively releasing the wheel brake of the front wheel 100 or the rear wheel 200.

In one embodiment, a sixth condition is established when the pedal displacement travel exceeds a third threshold, and the release brake signal is prevented from being transmitted after the sixth condition is established. When the sixth condition is met, the pedal displacement stroke exceeds the third threshold value, which indicates that the pilot has great reaction at the moment and emergency situations may occur, so that the function of sliding out and releasing the brake needs to be released, and the front wheels and the rear wheels of the airplane are kept in a brake state until the airplane decelerates to a safe state.

The five conditions can effectively identify the aircraft sliding-out stage, and effectively avoid mixing with other stages of the aircraft. And the sixth condition can avoid the airplane from releasing the brake by mistake, thereby ensuring the flight safety.

The wheel brake for releasing the front wheel 100 or the rear wheel 200 may be arbitrarily selected, or may be preferentially released in a portion having a higher temperature according to the entire wheel brake temperature. Preferably the number of wheels released one at a time is half the number of wheels in total.

When the number of the wheels needing to release the brake on the same side of the airplane exceeds half of the number of all the wheels on the same side, the brake control unit 80 sends out a first blocking signal to block the transmission of the brake release signal, so as to release the brake release function and prevent the moving path of the airplane from deviating.

In one embodiment, the braking state of the front wheel or the rear wheel is replaced when the frequency of the pedal signals changes, namely the braking state of the front wheel or the rear wheel can be changed by the frequency of the pedals stepped by the pilot, so that the braking of the airplane wheel is released alternately, and the integral heat dissipation effect of the airplane wheel is improved.

The method ensures that only part of the airplane wheels are braked to work in the stage from the sliding out of the parking apron to the taking-off of the airplane, or half of the airplane wheels with relatively low service temperature are braked by pedaling the brakes each time, so that the abrasion of the carbon disk can be reduced in the temperature range with the most sensitive abrasion, and the heat dissipation of the brakes is accelerated. At the braking temperature in the slipping-out stage, the release of the braking function has a significant benefit in reducing the wear of the carbon disk, thereby effectively reducing the wear of the carbon disk.

In addition, through using a Brake Control Unit (BCU) to control the instruction, only an instruction program is added in the original part, and only a signal in the brake system or a signal which is originally required to be received by the brake control unit is used for judging, so that the complexity of the system is not increased, and the calculation amount of the system and the burden of the BCU are not obviously increased.

The application also discloses a storage medium, wherein a computer program is stored on the storage medium, and when the program is executed by a processor, the steps of the brake releasing method in the slipping-out stage are carried out.

Although the present invention has been disclosed in terms of the preferred embodiment, it is not intended to limit the invention, and variations and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention. Therefore, any modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope defined by the claims of the present invention, unless the technical essence of the present invention departs from the content of the present invention.

Claims

1. A roll-out phase release brake system for releasing partial braking of a wheel in a roll-out phase, comprising:

the first logic judgment unit is used for judging whether the brake temperature reaches a first threshold value or not and sending a first signal when the brake temperature does not reach the first threshold value;

the second logic judgment unit is used for judging whether the wheel speed of the airplane reaches a second threshold value or not and sending a second signal when the wheel speed does not reach the second threshold value;

the third logic judgment unit is used for judging whether the pedal displacement stroke reaches a third threshold value or not and sending a third signal when the pedal displacement stroke does not reach the third threshold value;

and the brake control unit is configured to receive an automatic brake RTO gear pre-position signal, a throttle lever slow parking space signal and a pedal signal, receive the first signal, the second signal and the third signal, and transmit a brake release signal after simultaneously receiving the automatic brake RTO gear pre-position signal, the throttle lever slow parking space signal, the pedal signal, the first signal, the second signal and the third signal, so that the brake of a part of wheels is released alternatively.

2. A slide out phase release brake system as claimed in claim 1, wherein said brake control unit is further configured to count a number of times said pedal signal is applied and to release an alteration signal when said pedal number is varied, said alteration signal being capable of replacing a braking state of said wheel.

3. A slide out phase release brake system as claimed in claim 1 further comprising a fourth logic decision unit for comparing brake temperatures of all wheels and sending a priority signal to said brake control unit to preferentially release wheels with higher brake temperatures.

4. A slide-out phase release brake system as claimed in claim 1, wherein said third logic determination unit is configured to issue a fourth signal when said pedal displacement travel exceeds said third threshold, said fourth signal for transmission to said brake control unit to prevent transmission of said release brake signal.

5. A slide out phase release brake system as claimed in claim 1 wherein said brake control unit is further configured to identify the wheel position at which braking is released and to issue a first blocking signal to block the transmission of said brake release signal when the number of wheels on the same side of the aircraft requiring brake release exceeds half the total number of wheels on that same side.

6. A slide-out phase release brake system, as claimed in claim 1, wherein said first threshold is 300 ℃, said second threshold is 30 knots and said third threshold is 70% of maximum pedal displacement travel.

7. A slide-out phase release brake method, characterized in that the slide-out phase release brake system according to any one of claims 1 to 6 is used, comprising the steps of:

a fifth condition is established when a throttle lever slow parking space signal appears;

and when the first condition, the second condition, the third condition, the fourth condition and the fifth condition are all established, alternatively releasing the brake of the partial wheel.

8. A method of slide out phase release braking as claimed in claim 7 wherein the number of pedal signals varies to replace the braking status of the wheel.

9. A slide out phase release brake method as claimed in claim 7,

and when the pedal displacement stroke exceeds the third threshold value, a sixth condition is established, and the brake is stopped to be released after the sixth condition is established.

10. A method of skid out stage brake release as claimed in claim 7 wherein the number of wheels released one at a time is half the number of total wheels.

11. A slide out phase release brake method as claimed in claim 7,

the method preferentially releases the partial wheels with higher braking temperature in all wheels.

12. A storage medium on which a computer program is stored which, when being executed by a processor, carries out the steps of the method as claimed in claim 7.