CN110116800A - Brake control method of the Aircraft Anti-skid Break Control under anti-skidding failure - Google Patents
Brake control method of the Aircraft Anti-skid Break Control under anti-skidding failure Download PDFInfo
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- CN110116800A CN110116800A CN201910398255.0A CN201910398255A CN110116800A CN 110116800 A CN110116800 A CN 110116800A CN 201910398255 A CN201910398255 A CN 201910398255A CN 110116800 A CN110116800 A CN 110116800A
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- Prior art keywords
- brake
- pressure
- skidding
- failure
- skid
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/88—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means
- B60T8/92—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means automatically taking corrective action
- B60T8/94—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means automatically taking corrective action on a fluid pressure regulator
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C25/00—Alighting gear
- B64C25/32—Alighting gear characterised by elements which contact the ground or similar surface
- B64C25/42—Arrangement or adaptation of brakes
- B64C25/44—Actuating mechanisms
- B64C25/46—Brake regulators for preventing skidding or aircraft somersaulting
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Transportation (AREA)
- Aviation & Aerospace Engineering (AREA)
- Regulating Braking Force (AREA)
Abstract
Brake pressure is discharged into return pressure and maintains t by a kind of brake control method of Aircraft Anti-skid Break Control under anti-skidding failure while anti-sliding control failure occurs in anti-skid brake system (ABS), lights fault warning lamp and carries out phonic warning1, then apply the 70% of command signal corresponding pressure and maintain t2, n period is so executed, after the release repeatedly and application that control brake pressure, gives brake electric current according to the 70% of command signal corresponding pressure, actively decompression is to reduce the risk that anti-skid brake system (ABS) is skidded, while anti-skid brake system (ABS) real-time response pilot controls.The present invention generates a wrong sense by the brake pressure control in n period, reminds pilot's anti-skid brake system (ABS) anti-sliding control failure occur, while winning Deal with Time to pilot, avoids the locking during this period of wheel tire, prevent safety accident.
Description
Technical field
The present invention relates to aircraft brake control technology field, brake controlling party of specifically a kind of aircraft under anti-skidding failure
Method.
Background technique
For aircraft in landing mission, anti-skid brake system (ABS) is most important, after anti-skidding failure occurs in aircraft, if at failure
Reason method is not excellent, may endanger sliding race process, reduce and use full property, for example, after anti-skidding failure occurs in aircraft, lasting brake pressure
Power is excessive, in the lesser situation of ground friction coefficient, will cause wheel tire inordinate wear or even blows out.Cause this phenomenon
Basic reason, first is that the conventional anti-skidding fault handling method of anti-skid brake system (ABS) cannot make pilot accurately identify anti-skidding brake
Has there is anti-skidding failure in vehicle system；Second is that not account for pilot anti-for the conventional anti-skidding fault handling method of anti-skid brake system (ABS)
Deal with Time is answered, when pilot's disposition, wheel tire inordinate wear is had resulted in or even blows out.
Aircraft Anti-skid Break Control only carries out light alarm, if pilot does not see after anti-skidding failure occurs at present
It observes, continues to biggish brake pressure, in the lesser situation of ground friction coefficient, will cause wheel tire inordinate wear
Even blow out.
The conventional anti-skidding fault handling method of Aircraft Anti-skid Break Control is depressured without active, when touching on the brake deeply, wheel
Skidding locking risk is larger, handling unexcellent.
The conventional anti-skidding fault handling method of anti-skid brake system (ABS) has the disadvantage in that
1. pilot identifies that anti-skidding fault method is single, heavy dependence pilot's visual determination；
2. being unable to active decompression after anti-skidding failure, slip risk cannot be reduced；
3. not increasing risk of blowing out to pilot's given processing time after anti-skidding failure；
4. Aircraft Anti-skid Break Control safety in utilization is low.
Master's thesis " airplane hydraulic pressure anti-skid brake system (ABS) failure disclosed in Harbin Engineering University on January 1st, 2008
Diagnosis research " in using the fault diagnosis expert system method based on fault tree to airplane hydraulic pressure anti-skid brake system (ABS) carry out failure
Diagnosis.Anti-skidding failure Disposal Measures are not studied in detail.
Summary of the invention
For overcome it is existing in the prior art when anti-skid brake system (ABS) safety in utilization is low, occur anti-skidding failure after pilot
There is no Deal with Time, there are the deficiencies of security risk, and the invention proposes a kind of Aircraft Anti-skid Break Controls under anti-skidding failure
Brake control method.
Detailed process of the invention is:
Step 1 determines anti-skid brake system (ABS) with the presence or absence of anti-skidding failure.
Identify that anti-skid brake system (ABS) whether there is anti-skidding failure by the fault diagnosis functions of antiskid braking control box, including
Speed acquisition channel failure and speed sensor fault.
The anti-skidding failure of the determination includes speed acquisition channel failure and speed sensor fault.
Step 2, the pressure release of brake pressure.
The period is disposed to the brake pressure progress pressure release by n anti-skidding failures.
One anti-skidding failure disposition period include one by brake pressure pressure release be discharged into return pressure process and one
Apply the process of 70% brake pressure.
The when a length of t of brake pressure pressure release release1, a length of t when applying stressed2。
The duration t of the pressure leak process1=0.3s~0.8s；The duration t of pressure process2=0.3s~0.8s；
It include pressure leak process and pressure process in an anti-skidding failure disposition period.
During the pressure release release in each anti-skidding failure disposition period, stopped by formula (1) and formula (2) real-time control
Vehicle electric current Ib repeats the anti-skidding failure disposition period n times, realizes the implementation control of brake pressure.
Pressure leak process, Ib=0 (1)
Pressure process, Ib=0.7kVb (2)
K is brake electric current design factor in formula (1), and Vb brake instruction signal, Ib is brake electric current.
If anti-skidding failure vanishes, anti-skid brake system (ABS) is restored to work normally, and is controlled by normal braking.
Step 3, brake pressure control.
After carrying out n period brake pressure bang-bang control, keep described corresponding with the brake pressure of pressure process
Brake the corresponding brake pressure of electric current Ib and 0.7K Vb, until brake terminates.
So far, brake control of the Aircraft Anti-skid Break Control under anti-skidding failure is completed.
If the anti-skidding failure vanishes being arranged, anti-skid brake system (ABS) is restored to work normally, and is controlled by normal braking.
In the present invention, when anti-sliding control failure occurs in anti-skid brake system (ABS), lights fault warning lamp and carry out phonic warning
While, brake pressure is discharged into return pressure and maintains t1, then apply the 70% of command signal corresponding pressure and maintain t2,
N period is so executed, it is given according to the 70% of command signal corresponding pressure after controlling the release repeatedly of brake pressure and applying
Brake electric current.The t1To discharge the brake pressure period；The t2To apply the brake pressure period.N period brake pressure switch
First is that can produce a wrong sense, has there is anti-sliding control failure in prompting pilot's anti-skid brake system (ABS) for formula control；Second is that flight
Member's given processing time, avoid the locking during this period of wheel tire.
If it is detected that anti-sliding control failure, the present invention can be reminded from vision, voice and switching regulator wrong sense etc. is many-sided
Currently has there is anti-sliding control failure in pilot, solves the problems, such as that pilot identifies that anti-skidding fault method is single.Occur anti-skidding
After controlling failure, the present invention first carries out n period brake pressure bang-bang control, to pilot's given processing time, reduces
Blow out risk, give brake electric current according still further to the 70% of command signal corresponding pressure, can active decompression, reduce slip risk.
It, can be with using actively decompression of the invention after pilot identifies that anti-sliding control failure occurs in current anti-skid brake system (ABS)
The risk that anti-skid brake system (ABS) is skidded is reduced, while anti-skid brake system (ABS) real-time response pilot controls.
The anti-skidding fault handling method of Aircraft Anti-skid Break Control of the invention and the anti-skidding event of conventional airplane anti-skid brake system (ABS)
Barrier processing method comparison is shown in Table 1.
The control method of the present invention of table 1 and conventional control methods contrast table
Figure of description
Fig. 1 is the schematic diagram of pressure leak process and pressure process.
Fig. 2 is flow chart of the invention.
In figure: 1. anti-skidding failures；2. pressure leak process；3. showing pressure process.
Specific embodiment
The present embodiment is a kind of brake control method of Aircraft Anti-skid Break Control under anti-skidding failure, and what is be applicable in is anti-skidding
Brake system is using conventional fax anti-skid brake system (ABS) or conventional complete electric anti-skid brake system (ABS).It is described in the present embodiment
Anti-skid brake system (ABS) is using conventional fax anti-skid brake system (ABS).
The present embodiment the following steps are included:
Step 1 determines anti-skid brake system (ABS) with the presence or absence of anti-skidding failure.
Identify that anti-skid brake system (ABS) whether there is anti-skidding failure by the fault diagnosis functions of antiskid braking control box, including
Speed acquisition channel failure and speed sensor fault.When recognizing anti-skidding failure 1, light alarm and phonic warning are carried out.
Step 2, the periodical pressure release of brake pressure.
The period is disposed to the brake pressure progress pressure release by n anti-skidding failures；N=4~20.
It is described when driving light fault warning lamp and carry out phonic warning while, the anti-skid brake system (ABS) will brake pressure
Power is discharged into return pressure, when release a length of t1；Apply 70% brake pressure, when pressurization a length of t2.Brake pressure
The process for being discharged into return pressure and the primary brake pressure for applying 70% is that an anti-skidding failure disposes the period.
In the anti-skidding failure disposition period, brake pressure is in cyclically-varying.It is described that brake pressure is discharged into oil return
The process of pressure is known as pressure leak process 2；The process of the brake pressure for applying 70% is known as pressure process 3.
In the pressure release, by formula (1) and formula (2) real-time control brake electric current Ib, the anti-skidding event is repeated
Barrier disposition period n times realize the implementation control of brake pressure.
Pressure leak process, Ib=0 (1)
Pressure process, Ib=0.7kVb (2)
The duration t of pressure leak process described in formula (1)1Value range is 0.3s~0.8s；The duration t of pressure process2Value
Range is 0.3s~0.8s；The duration of the pressure leak process and the duration of pressure process are identical or different.K is that brake electric current calculates
Coefficient, Vb brake instruction signal, Vb=0~5.
In the present embodiment, n=8 is taken, carries out the brake pressure bang-bang control in 8 anti-skidding failure disposition periods.Formula (1)
The duration t of middle pressure leak process1For 0.5s, pressure process t in formula (2)2For 0.5s, the electric current that brakes calculates coefficient k value 2.2, stops
Vehicle command signal Vb value 4.
After there is anti-skidding failure, each cycle first discharges 0.5s brake pressure, i.e. brake pressure is 0；Apply 0.5s's again
The corresponding brake pressure of 6.16mA, within the total 8s period in 8 periods of progress, brake pressure presses bang-bang control, gives pilot
The processing time is provided, reduces risk of blowing out, while there is anti-lock ability.
If anti-skidding failure vanishes, anti-skid brake system (ABS) is restored to work normally, and is controlled by normal braking.
Step 3, brake pressure control.
After carrying out n period brake pressure bang-bang control, keep described corresponding with the brake pressure of pressure process
Brake the corresponding brake pressure of electric current Ib and 0.7K Vb, until brake terminates.
So far, brake control of the Aircraft Anti-skid Break Control under anti-skidding failure is completed.
In the present embodiment, the brake electric current calculates COEFFICIENT K value 2.2, brake instruction signal Vb value 4.
If anti-skidding failure vanishes, anti-skid brake system (ABS) is restored to work normally, and is controlled by normal braking.
After brake system has identified that anti-sliding control failure occurs in current anti-skid brake system (ABS), brake pressure is reduced, thus
The risk for reducing anti-skid brake system (ABS) skidding by converting the value of Vb, and makes Ib by formula (2) response transform, anti-skidding brake
Vehicle system real-time response pilot control is handling good.
In the present embodiment, by the anti-skidding failure of setting, so that anti-skid brake system (ABS) is met entry condition of the present invention and is tested,
Test result shows the present invention after anti-skidding failure, reminds pilot to work as from vision, voice and switching regulator wrong sense etc. is many-sided
It is preceding anti-sliding control failure occurred, solve the problems, such as that pilot identifies that anti-skidding fault method is single；After anti-sliding control failure, this
Invention first carries out 8 period brake pressure bang-bang controls, handles the time given 8s to pilot, reduces risk of blowing out,
The corresponding brake pressure of 8.8mA is actively reduced to the corresponding brake pressure of 6.16mA again, reduces anti-skid brake system (ABS) skidding
Risk.The control method improves Aircraft Anti-skid Break Control safety in utilization.
Claims (4)
1. a kind of brake control method of Aircraft Anti-skid Break Control under anti-skidding failure, which is characterized in that detailed process is:
Step 1 determines anti-skid brake system (ABS) with the presence or absence of anti-skidding failure:
Identify whether anti-skid brake system (ABS) anti-skidding failure, including speed occurs by the fault diagnosis functions of antiskid braking control box
Acquisition channel failure and speed sensor fault；
Step 2, the pressure release of brake pressure:
The period is disposed to the brake pressure progress pressure release by n anti-skidding failures；
One anti-skidding failure disposition period includes the process and an application that brake pressure pressure release is discharged into return pressure
The process of 70% brake pressure；
During the pressure release release in each anti-skidding failure disposition period, braked by formula (1) and formula (2) real-time control electric
Ib is flowed, the anti-skidding failure disposition period n times is repeated, realizes the implementation control of brake pressure；
Pressure leak process, Ib=0 (1)
Pressure process, Ib=0.7kVb (2)
K is brake electric current design factor in formula (1), and Vb brake instruction signal, Ib is brake electric current；
If anti-skidding failure vanishes, anti-skid brake system (ABS) is restored to work normally, and is controlled by normal braking；
Step 3, brake pressure control:
After carrying out n period brake pressure bang-bang control, the brake corresponding with the brake pressure of pressure process is kept
The corresponding brake pressure of electric current Ib and 0.7K Vb, until brake terminates；
So far, brake control of the Aircraft Anti-skid Break Control under anti-skidding failure is completed；
If the anti-skidding failure vanishes being arranged, anti-skid brake system (ABS) is restored to work normally, and is controlled by normal braking.
2. brake control method of the Aircraft Anti-skid Break Control as described in claim 1 under anti-skidding failure, which is characterized in that institute
Stating determining anti-skidding failure includes speed acquisition channel failure and speed sensor fault.
3. brake control method of the Aircraft Anti-skid Break Control as described in claim 1 under anti-skidding failure, which is characterized in that institute
Stating the anti-skidding failure disposition period is the mistake that brake pressure is once discharged into the brake pressure of return pressure and primary application 70%
Journey.
4. brake control method of the Aircraft Anti-skid Break Control as claimed in claim 3 under anti-skidding failure, which is characterized in that institute
State the when a length of t of brake pressure pressure release release1, t1=0.3s~0.8s；A length of t when applying stressed2,
t2=0.3s~0.8s.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910398255.0A CN110116800B (en) | 2019-05-14 | 2019-05-14 | Brake control method of airplane antiskid brake system under antiskid fault |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910398255.0A CN110116800B (en) | 2019-05-14 | 2019-05-14 | Brake control method of airplane antiskid brake system under antiskid fault |
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| CN110116800A true CN110116800A (en) | 2019-08-13 |
| CN110116800B CN110116800B (en) | 2022-12-13 |
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| CN201910398255.0A Active CN110116800B (en) | 2019-05-14 | 2019-05-14 | Brake control method of airplane antiskid brake system under antiskid fault |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113467984A (en) * | 2021-07-20 | 2021-10-01 | 中国商用飞机有限责任公司北京民用飞机技术研究中心 | Aircraft system fault diagnosis method and device, computer equipment and storage medium |
| CN113895606A (en) * | 2021-09-23 | 2022-01-07 | 西安航空制动科技有限公司 | Antiskid fault handling method for aircraft brake system |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030025035A1 (en) * | 2001-05-23 | 2003-02-06 | Duk-Hyun Park | Optimal control design for aircraft antiskid brake control systems |
| CN102490708A (en) * | 2011-11-25 | 2012-06-13 | 苏州市职业大学 | Safe hill-start device for automobile |
| CN103018027A (en) * | 2012-12-07 | 2013-04-03 | 西安航空制动科技有限公司 | Method for exciting faults of airplane brake valve |
| CN104819836A (en) * | 2015-05-06 | 2015-08-05 | 西安航空制动科技有限公司 | Method for verifying internal leakage fault of aircraft brake valve |
| CN105523179A (en) * | 2014-09-28 | 2016-04-27 | 中国航空工业集团公司西安飞机设计研究所 | Aircraft brake pressure feedback regulation system and aircraft brake pressure feedback regulation method |
| CN106218871A (en) * | 2016-07-25 | 2016-12-14 | 西安航空制动科技有限公司 | Aircraft brake anti-skid control method and airplane brake system |
| CN106394881A (en) * | 2016-10-18 | 2017-02-15 | 西安航空制动科技有限公司 | Power-on self-test protection method for anti-skid brake system of airplane |
| CN106672219A (en) * | 2016-12-22 | 2017-05-17 | 西安航空制动科技有限公司 | Airplane slip-prevention failure speed state locking method |
-
2019
- 2019-05-14 CN CN201910398255.0A patent/CN110116800B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030025035A1 (en) * | 2001-05-23 | 2003-02-06 | Duk-Hyun Park | Optimal control design for aircraft antiskid brake control systems |
| CN102490708A (en) * | 2011-11-25 | 2012-06-13 | 苏州市职业大学 | Safe hill-start device for automobile |
| CN103018027A (en) * | 2012-12-07 | 2013-04-03 | 西安航空制动科技有限公司 | Method for exciting faults of airplane brake valve |
| CN105523179A (en) * | 2014-09-28 | 2016-04-27 | 中国航空工业集团公司西安飞机设计研究所 | Aircraft brake pressure feedback regulation system and aircraft brake pressure feedback regulation method |
| CN104819836A (en) * | 2015-05-06 | 2015-08-05 | 西安航空制动科技有限公司 | Method for verifying internal leakage fault of aircraft brake valve |
| CN106218871A (en) * | 2016-07-25 | 2016-12-14 | 西安航空制动科技有限公司 | Aircraft brake anti-skid control method and airplane brake system |
| CN106394881A (en) * | 2016-10-18 | 2017-02-15 | 西安航空制动科技有限公司 | Power-on self-test protection method for anti-skid brake system of airplane |
| CN106672219A (en) * | 2016-12-22 | 2017-05-17 | 西安航空制动科技有限公司 | Airplane slip-prevention failure speed state locking method |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113467984A (en) * | 2021-07-20 | 2021-10-01 | 中国商用飞机有限责任公司北京民用飞机技术研究中心 | Aircraft system fault diagnosis method and device, computer equipment and storage medium |
| CN113467984B (en) * | 2021-07-20 | 2024-03-29 | 中国商用飞机有限责任公司北京民用飞机技术研究中心 | Method, device, computer equipment and storage medium for diagnosing faults of aircraft system |
| CN113895606A (en) * | 2021-09-23 | 2022-01-07 | 西安航空制动科技有限公司 | Antiskid fault handling method for aircraft brake system |
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| CN110116800B (en) | 2022-12-13 |
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