FAULT TOLERANT AIRCRAFT BRAKING CONTROL USING ALTERNATE WHEEL SPEED INFORMATION

• US 20100117447A1
• Filed: 02/21/2008
• Published: 05/13/2010
• Est. Priority Date: 05/21/2007
• Status: Active Grant

• Current Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Cahill, Eric D.
• Granted Patent: US 8,029,074 B2
• Time in Patent Office: Days
• US Class Current: 303/126
• CPC Class Codes: B60T 2270/402 Back-up
• CPC Class Codes: B60T 2270/416 Wheel speed sensor failure
• CPC Class Codes: B60T 8/1703 for aircrafts
• CPC Class Codes: B60T 8/885 using electrical circuitry

Abstract

A method for providing anti-skid braking control for a vehicle having a plurality of wheels, each wheel including a corresponding wheel speed sensor and brake, wherein when velocity data from at least one wheel speed sensor is lost, velocity data from a wheel speed sensor coupled to a different wheel is used as the wheel speed for the wheel with the non-operational sensor.

Claims

1. A method for deriving a brake signal indicative of a stopping force to be applied by at least one brake of a vehicle, said vehicle including a plurality of wheels, each wheel including a corresponding wheel speed sensor for detecting wheel speed and a brake for providing a stopping force to the wheel, comprising:

determining if the wheel speed sensors are functional or malfunctional; and

generating a brake signal for a brake corresponding to a malfunctional wheel speed sensor based on wheel speed data from a functional wheel speed sensor.

2. The method according to claim 1, wherein generating the brake signal includes:

applying a compensation factor to the generated brake signal to derive a compensated brake signal; and

using the compensated brake signal as the brake signal for the brake corresponding to the malfunctional wheel speed sensor.

3. The method according to claim 2, wherein applying the compensation factor includes limiting the compensated brake signal to a level less than a normal brake signal provided to a brake corresponding to the functional wheel speed sensor.

4. The method according to claim 3, wherein limiting the compensated brake signal includes limiting the compensated brake signal to a fixed or variable level below the normal brake signal.

5. The method according to claim 4, wherein limiting the compensated brake signal to a variable level includes a level that varies with respect to time.

6. The method according to claim 3, wherein limiting the compensated brake signal includes limiting the compensated brake signal to be less than a non-negative fraction of the normal brake signal.

7. The method according claim 2, wherein applying the compensation factor includes varying, after a wheel skid, a recovery rate of the compensated brake signal relative to a recovery rate of the normal brake signal.

8. The method according to claim 7, wherein varying the recovery rate includes increasing the compensated brake signal at a rate that is slower than a rate of increase of the normal brake signal.

9. The method according to claim 7, wherein varying the recovery rate for the compensated brake signal includes using a first recovery rate for high variability in friction coefficients between a surface and the wheels, and using a second recovery rate for low variability in friction coefficients between the surface and the wheels, wherein the second recovery rate is faster than the first recovery rate.

10. The method according to claim 1, wherein generating the brake signal includes using a wheel speed data from a wheel that is physically nearest to the wheel with the malfunctioning wheel speed sensor.

11. A system for braking a vehicle having a plurality of wheels, comprising:

a plurality of brakes, each brake of the plurality of brakes corresponding to one wheel of the plurality of wheels;

a plurality of wheel speed sensors, each wheel speed sensor of the plurality of wheel speed sensors corresponding to one brake of the plurality of brakes;

a brake controller operatively coupled to the plurality of brakes and to the plurality of wheel speed sensors, said brake controller including

logic that determines if the wheel speed sensors are functional or malfunctional; and

logic that generates a brake signal for a brake corresponding to a malfunctional wheel speed sensor based on wheel speed data from a functional wheel speed sensor.

13. The system according to claim 11, wherein the logic that generates the brake signal includes:

logic or code that applies a compensation factor to the generated brake signal to derive a compensated brake signal; and

logic or code that uses the compensated brake signal as the brake signal for the brake corresponding to the malfunctional wheel speed sensor.

14. The system according to claim 13, wherein the logic or code that applies the compensation factor includes logic or code that limits the compensated brake signal to a level less than a normal brake signal provided to a brake corresponding to the functional wheel speed sensor.

15. The system according to claim 14, wherein the logic or code that limits the compensated brake signal includes logic or code that limits the compensated brake signal to a fixed or variable level below the normal brake signal.

16. The system or controller according to claim 15, wherein the logic or code that limits the compensated brake signal to a variable level includes logic or code that uses a level that varies with respect to time.

17. The system according to claim 14, wherein the logic or code that limits the compensated brake signal includes logic or code that limits the compensated brake signal to be less than a non-negative fraction of the normal brake signal.

18. The system according to claim 13, wherein logic or code that applies the compensation factor includes logic or code that varies, after a wheel skid, a recovery rate of the compensated brake signal relative to a recovery rate of the normal brake signal.

19. The system according to claim 18, wherein the logic or code that varies the recovery rate includes logic or code that increases the compensated brake signal at a rate that is slower than a rate of increase of the normal brake signal.

20. The system according to claim 18, wherein logic or code that varies the recovery rate for the compensated brake signal includes logic or code that uses a first recovery rate for high variability in friction coefficients between a surface and the wheels, and uses a second recovery rate for low variability in friction coefficients between the surface and the wheels, wherein the second recovery rate is faster than the first recovery rate.

21. The system according to claim 11, wherein the logic or code that generates the brake signal includes logic or code that uses a wheel speed data from a wheel that is physically nearest to the wheel with the malfunctioning wheel speed sensor.

12. A brake controller for generating a braking signal for braking a vehicle having a plurality of wheels, each wheel including a corresponding brake and wheel speed sensor, comprising:

a processor and memory;

a brake control code stored in memory and executable by the processor, said brake control code including;

code that determines if the plurality of wheel speed sensors are functional or malfunctional;

code that generates a brake signal for brakes corresponding to functional wheel speed sensors, said generation based on data from the corresponding functional wheel speed sensor; and

code that uses the generated brake signal as a brake signal for brakes corresponding to malfunctional wheel speed sensors.