Brake condition monitoring

• US 20040011596A1
• Filed: 06/19/2003
• Published: 01/22/2004
• Est. Priority Date: 08/04/2000
• Status: Active Grant

• 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
• Granted Patent: US 7,086,503 B2
• Time in Patent Office: Days
• US Class Current: 188/1.11W
• 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. A monitoring system for monitoring the condition of braking apparatus having facing friction surfaces and actuation means for urging said surfaces towards one another, the monitoring system being operable for detecting and recording actuations of the braking apparatus and being characterised in that it comprises means (4, 11, 12, 21, 24, 102, 103) for distinguishing, from other actuations, wear generating actuations in which said surfaces come into contact with one another and move relative to one another over the surfaces and generate significant wear of those surfaces, the monitoring system further comprising means (13, 25, 105) capable of making available brake condition information dependent upon said wear generating actuations.

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 an 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 or 3, 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 any preceding claim, 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 apparatus, said parameters including some having values dependent upon wear in the system and different faults of the system; and

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

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

(i) signal receiving and storing means connected to said sensor means for receiving said signals and storing an on-going record thereof;

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

(iii) signalling means for signalling said wear and/or said possible fault.

11. A 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 or 11 wherein the signal processing means is operable to compare said signals against predetermined expected values thereof.

13. A monitoring system according to claim 10, 11 or 12, wherein the signal processing means is operable on the basis of a trend of the values of one of said signals during a plurality of successive brake applications to predict an expected value of said signal during a subsequent brake application, 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, 11 or 12, wherein the signalling means is operable for signalling said wear and/or said possible fault to a local operator of the said apparatus on a real time basis;

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

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

16. A monitoring system according to any one of claims 10 to 15, wherein said apparatus is an aircraft and said braking system is a wheel braking system of the aircraft.

17. A monitoring system according to any one of claims 10 to 16, wherein the signal processing means is operable for distinguishing between respective categories of brake application distinguished by respective combinations of intensity and duration of the application, for sensing braking performance during brake applications, and for predicting braking performance during future applications of the same or a different category.

18. A monitoring system according to any of claims 9 to 15, wherein said parameters includes input parameters that may affect the operation of said braking system and output parameters that are affected by the operation of the braking system.

19. A monitoring system according to claim 18, wherein said input parameters include one or more of braking demand, brake application duration and the speed of movement and weight of the apparatus in which the braking system is comprised.

20. A monitoring system according to claim 18 or 19, wherein said output parameters include one or more of brake torque, brake temperature, vibration, acoustic signature, acceleration and brake odour.

21. A method for monitoring the condition of braking apparatus having facing friction surfaces and actuation means for urging said surfaces towards one another, the method including detecting and recording actuations of the apparatus and the method being characterised in that it comprises distinguishing, from other actuations, those wear generating actuations in which said surfaces come into contact with one another and move relative to one another over the said surfaces and generate significant wear of those surfaces, the method further comprising providing brake condition information dependent upon said wear generating actuations.

22. A method according to claim 21, 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.

23. A method according to claim 22, comprising:

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

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

identifying and recording the existence of said wear and said faults.