Brake condition monitoring

• US 7,086,503 B2
• Filed: 08/03/2001
• Issued: 08/08/2006
• Est. Priority Date: 08/04/2000
• Status: Expired due to Term

• Current Assignee: Meggitt Aerospace Ltd. (Meggitt PLC)
• Original Assignee: Dunlop Aerospace Ltd. (Meggitt PLC)
• Inventors: Miller, Richard John, Bailey, David Alexander, Marshall, Ross John, Griffin, Nicholas Charles
• Primary Examiner(s): Rodriguez, Pam
• Application Number:
  US10/343,131
• Publication Number:
  US 20040011596A1
• Time in Patent Office: 1,831 Days
• Field of Search: 188/1.11 W, 188/1.11 L, 188/1.11 E, 188/1.11 R, 188/79.51, 188/79.52, 340/449, 340/453, 340/454, 374/7, 374/110, 374/111, 374/135, 374/163, 374/179, 377/15, 377/16, 377/25, 701/29, 701/30, 303/122, 303/122.03, 303/122.02, 303/122.04, 303/122.08, 303/DIG.3, 244/110.A, 244/111
• US Class Current: 188/1.11L
• CPC Class Codes: B60T 17/22 Devices for monitoring or checking brake systems; Signal devices
• CPC Class Codes: B60T 17/221 Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems hydraulic pressure systems in general F15B19/00, F15B21/04; testing structures or apparatus G01M
• CPC Class Codes: B64C 25/42 Arrangement or adaptation of brakes
• CPC Class Codes: B64F 5/60 Testing or inspecting aircraft components or systems
• CPC Class Codes: F16D 2066/001 Temperature
• CPC Class Codes: F16D 2066/003 Position, angle or speed
• CPC Class Codes: F16D 2066/005 Force, torque, stress or strain
• CPC Class Codes: F16D 2066/006 without direct measurement of the quantity monitored, e.g. wear or temperature calculated form force and duration of braking
• CPC Class Codes: F16D 66/02 Apparatus for indicating wear
• CPC Class Codes: G06Q 40/12 Accounting

Abstract

System and method for monitoring the applications of the brakes, e.g. of an aircraft to determine brake condition and operate a brake maintenance programme or charge a brake system user. It is desirable to have accurate information for determining the condition and predicting the life of carbon-carbon brake discs. This is important for safety as well as commercial reasons. The number of landings of an aircraft is often used as a determinant for such as lifetime warranties for brake discs and recommended maintenance periods. However, at least for carbon disc brakes, this may not be entirely accurate. For example such brake discs also wear during taxiing. The system and method herein includes monitoring each actuation of the brakes and making a separate record of each actuation of the brakes in which there is relative movement of the facing friction surfaces that cause wear, and from that separate record determining brake usage. The monitoring may include measuring changes and processing the signals to distinguish between those which fall below and those which are above a threshold value. Herein there is also described, a method and apparatus for monitoring a braking system comprising sensing a plurality of braking parameters having values dependent upon wear in the system and different faults of the system, and identifying and recording wear and faults based on combinations of values of said parameters.

Claims

1. An aircraft wheel braking apparatus monitoring system for monitoring the condition of carbon-carbon aircraft wheel braking apparatus, the braking apparatus having facing friction surfaces and actuation means for urging the friction surfaces towards one another, said monitoring system being operable for detecting, recording and categorizing actuations of the braking apparatus and for distinguishing, from other actuations of the braking apparatus, wear generating actuations wherein the friction surfaces come into contact with one another to generate significant wear of those surfaces, said monitoring system also being operable for providing a signal indicative of the category of said wear generating actuations and for providing information regarding the braking apparatus performance in response to said signal, and said monitoring system is further operable for predicting future performance of braking applications.

2. A monitoring system according to claim 1, including means for generating a signal according to changes of increase in temperature of the brake members on actuation of the brakes and means for distinguishing between those non-wear generating actuations which cause an increase below a threshold value of the temperature increase parameter and those wear generating actuations which cause and increase above a threshold value.

3. A monitoring system according to claim 2 including means for processing the signals to distinguish between those which fall below and those which are above the threshold value.

4. A monitoring system according to claim 2 wherein means are present for filtering and differentiating the signal.

5. A monitoring system according to claim 4, wherein the differentiating means is arranged to differentiate the signal twice.

6. A monitoring system according to claim 1, comprising a stand alone unit and a dedicated battery therefor.

7. A monitoring system according to claim 6, including means for disabling the battery.

8. A monitoring system according to claim 7, wherein a tilt switch and/or motion sensor are present as the disabling means.

9. A monitoring system according to claim 1, comprising:

sensor means coupled to the braking apparatus for sensing a plurality of parameters associated with the operation of the braking apparatus, the parameters including some having values dependent upon wear in the braking apparatus and different possible faults of the braking apparatus; and

processing means for identifying respective signature combinations of values of the parameters, which combinations are representative of operation of the braking apparatus whilst it is subject to different degrees of the wear in the braking apparatus and different ones of the faults of the braking apparatus, said processing means being further operable for identifying and recording the existence of the wear in the braking apparatus and the faults of the braking apparatus.

10. A monitoring system according to claim 9, comprising:

signal receiving and storing means connected to said sensor means for receiving signals therefrom indicative of the parameters of one or both of braking apparatus wear and possible braking system fault and storing an on-going record thereof;

signal processing means for monitoring said record and for identifying changes in one or more of said signals indicative of one or both of braking apparatus wear and a possible braking system fault, and

signaling means for signaling the wear and/or the possible fault.

11. The monitoring system according to claim 10, wherein the signal processing means is operable to compare present values of said signals against said on-going record thereof.

12. A monitoring system according to claim 10, wherein the signal processing means is operable to compare said signals against predetermined expected values thereof.

13. A monitoring system according to claim 10, wherein said signal processing means is operable on the basis of a trend of the values of one of said signals during a plurality of successive applications of the braking apparatus to predict an expected value of said one of said signals during a subsequent application of the braking apparatus, and for comparing the actual value of said one signal against said expected value.

14. A monitoring system according to claim 13, wherein said signal processing means is operable to identify the said trend by statistical analysis of the values of said one signal during said plurality of successive brake applications.

15. A monitoring system according to claim 10, wherein the signaling means is operable for signaling said wear and/or said possible fault to a local operator of the said braking apparatus on a real time basis;

and/or for signaling said wear and/or said possible fault to a remote operator via wireless communication means; and

/or for signaling said wear and/or said possible fault by making data available to a local data port for periodic off-line access.

16. A monitoring system according to claim 9, wherein the parameters includes input parameters that may affect the operation of said braking apparatus and output parameters that are affected by the operation of the braking apparatus.

17. A monitoring system according to claim 16, wherein the input parameters include one or more of braking apparatus demand, braking apparatus application duration and the speed of movement and weight of the aircraft.

18. A monitoring system according to claim 16, wherein said output parameters include one or more of braking apparatus torque, braking apparatus temperature, vibration, acoustic signature, acceleration and braking apparatus odor.

19. A monitoring system according to claim 1, wherein the monitoring system includes signal processing means for distinguishing between respective categories of applications of the braking apparatus distinguished by respective combinations of intensity and duration of the applications, for sensing braking performance during applications of the braking apparatus, and for predicting braking performance of the braking apparatus during future applications of the same or a different category.

20. A monitoring system according to claim 1, wherein said monitoring system is operable to receive at least one signal from a set of signals consisting of signals indicative of brake hydraulic pressure, brake temperature, wheel speed, brake torque, brake application time, brake odor, brake acoustic signature, brake chassis acceleration and brake vibration and to process said at least one signal for use in detecting and categorizing actuations of the braking apparatus.

21. An aircraft comprising an aircraft wheel braking apparatus monitoring system according to claim 1.

22. A method of monitoring the condition of carbon-carbon aircraft wheel braking apparatus, the braking apparatus having facing friction surfaces and actuation means for urging the friction surfaces towards one another, said method comprising:

detecting, recording and categorizing actuations of the braking apparatus;

distinguishing, from other actuations of the braking apparatus, wear generating actuations wherein the friction surfaces come into contact with one another to generate significant wear of those surfaces, the wear generating actuations resulting in different degrees of wear of those surfaces, said method further comprising providing a signal indicative of the category of said wear generating actuations and for providing information regarding the braking apparatus performance in response to said signal, and wherein said method further comprises predicting future performance of the braking apparatus in the same or different categories of braking applications.

23. A method according to claim 22, including the steps of:

detecting a change in temperature of the brake members on actuation of the brakes;

generating a signal according to the detected changes, and

identifying from the signal those actuations which cause a change in a temperature increase parameter above a pre-selected threshold value.

24. A method according to claim 22, comprising:

during an operation of the braking apparatus, sensing a plurality of parameters associated with the braking apparatus, the parameters including some having values dependent upon wear in the braking apparatus and different faults of the braking apparatus;

identifying respective signature combinations of values of the parameters, which combinations are representative of operation of the braking apparatus whilst it is subject to the different degrees of the wear in the braking apparatus and different ones of the faults of the braking apparatus; and

identifying and recording the existence of the wear in the braking apparatus and the faults of the braking apparatus.

25. An aircraft wheel braking apparatus monitoring system for monitoring the condition of carbon-carbon aircraft wheel braking apparatus, the braking apparatus having facing friction surfaces and actuation means for urging the friction surfaces towards one another, said monitoring system being operable for detecting, recording and categorizing actuations of the braking apparatus including at least two from a set of aircraft braking apparatus actuations consisting of braking when landing, braking when taxiing, braking when stationary, braking prior to undercarriage retraction and braking during a rejected take off and for distinguishing, from other actuations of the braking apparatus, wear generating actuations wherein the friction surfaces come into contact with one another to generate significant wear of those surfaces, said monitoring system also being operable for providing a signal indicative of the category of said wear generating actuations and for providing information regarding the braking apparatus performance in response to said signal, and said monitoring system is further operable for predicting future performance of braking applications.

26. A monitoring system according to claim 25, comprising:

sensor means coupled to the braking apparatus for sensing a plurality of parameters associated with the operation of the braking apparatus, the parameters including some having values dependent upon wear in the braking apparatus and different possible faults of the braking apparatus; and

processing means for identifying respective signature combinations of values of the parameters, which combinations are representative of operation of the braking apparatus whilst it is subject to different degrees of the wear in the braking apparatus and different ones of the faults of the braking apparatus, said processing means being further operable for identifying and recording the existence of the wear in the braking apparatus and the faults of the braking apparatus.

27. A monitoring system according to claim 26, comprising:

signal receiving and storing means connected to said sensor means for receiving signals therefrom indicative of the parameters of one or both of braking apparatus wear and possible braking system fault and storing an on-going record thereof;

signal processing means for monitoring said record and for identifying changes in one or more of said signals indicative of one or both of braking apparatus wear and a possible braking system fault, and

signaling means for signaling the wear and/or the possible fault.

28. The monitoring system according to claim 27, wherein the signal processing means is operable to compare present values of said signals against said on-going record thereof.

29. A monitoring system according to claim 27, wherein the signal processing means is operable to compare said signals against predetermined expected values thereof.

30. A monitoring system according to claim 27, wherein said signal processing means is operable on the basis of a trend of the values of one of said signals during a plurality of successive applications of the braking apparatus to predict an expected value of said one of said signals during a subsequent application of the braking apparatus, and for comparing the actual value of said one signal against said expected value.

31. A monitoring system according to claim 30, wherein said signal processing means is operable to identify the said trend by statistical analysis of the values of said one signal during said plurality of successive brake applications.

32. A monitoring system according to claim 27, wherein the signaling means is operable for signaling said wear and/or said possible fault to a local operator of the said braking apparatus on a real time basis;

and/or for signaling said wear and/or said possible fault to a remote operator via wireless communication means; and

/or for signaling said wear and/or said possible fault by making data available to a local data port for periodic off-line access.

33. A monitoring system according to claim 26, wherein the parameters includes input parameters that may affect the operation of said braking apparatus and output parameters that are affected by the operation of the braking apparatus.

34. A monitoring system according to claim 33, wherein the input parameters include one or more of braking apparatus demand, braking apparatus application duration and the speed of movement and weight of the aircraft.

35. A monitoring system according to claim 33, wherein said output parameters include one or more of braking apparatus torque, braking apparatus temperature, vibration, acoustic signature, acceleration and braking apparatus odor.

36. A monitoring system according to claim 25, wherein the monitoring system includes signal processing means for distinguishing between respective categories of applications of the braking apparatus distinguished by respective combinations of intensity and duration of the applications, for sensing braking performance during applications of the braking apparatus, and for predicting braking performance of the braking apparatus during future applications of the same or a different category.

37. A monitoring system according to claim 25, wherein said monitoring system is operable to receive at least one signal from a set of signals consisting of signals indicative of brake hydraulic pressure, brake temperature, wheel speed, brake torque, brake application time, brake odor, brake acoustic signature, brake chassis acceleration and brake vibration and to process said at least one signal for use in detecting and categorizing actuations of the braking apparatus.

38. An aircraft comprising an aircraft wheel braking apparatus monitoring system according to claim 25.

39. A method of monitoring the condition of carbon-carbon aircraft wheel braking apparatus, the braking apparatus having facing friction surfaces and actuation means for urging the friction surfaces towards one another, said method comprising:

detecting, recording and categorizing actuations of the braking apparatus including at least two from a set of aircraft actuations consisting of braking when landing, braking when taxiing, braking when stationary, braking prior to undercarriage retraction and braking during takeoff;

distinguishing, from other actuations of the braking apparatus, wear generating actuations wherein the friction surfaces come into contact with one another to generate significant wear of those surfaces, the wear generating actuations resulting in different degrees of wear of those surfaces, said method further comprising providing a signal indicative of the category of said wear generating actuations and for providing information regarding the braking apparatus performance in response to said signal, and wherein said method further comprises predicting future performance of the braking apparatus in the same or different categories of braking applications.

40. A method according to claim 39, comprising:

during an operation of the braking apparatus, sensing a plurality of parameters associated with the braking apparatus, the parameters including some having values dependent upon wear in the braking apparatus and different faults of the braking apparatus;

identifying respective signature combinations of values of the parameters, which combinations are representative of operation of the braking apparatus whilst it is subject to the different degrees of the wear in the braking apparatus and different ones of the faults of the braking apparatus; and

identifying and recording the existence of the wear in the braking apparatus and the faults of the braking apparatus.