Brake system providing limited antiskid control during a backup mode of operation

Patent metadata

Field	Value
Publication number	US-2020407050-A1
Application number	US-201916451868-A
Country	US
Kind code	A1
Filing date	Jun 25, 2019
Priority date	Jun 25, 2019
Publication date	Dec 31, 2020
Grant date	—

Abstract

A brake system for a vehicle is disclosed and includes an energy storage device configured to store and discharge energy, a plurality of wheels having an observer wheel, one or more processors operatively coupled to the energy storage device, and a memory coupled to the one or more processors. The memory stores data comprising a database and program code that, when executed by the one or more processors, causes the brake system to determine the brake system is operating in a backup mode of operation. In response to determining the brake system is operating in the backup mode of operation, the brake system is caused to apply a first brake pressure command to the observer wheel. In response to determining the observer wheel is starting the skid condition, the brake system is caused to determine a second brake pressure command based on a target slip value.

First claim

What is claimed is:

1 . A brake system for a vehicle, wherein the brake system includes an energy storage device configured to store and discharge energy and a plurality of wheels that designate an observer wheel, the brake system comprising:
one or more processors operatively coupled to the energy storage device; and a memory coupled to the one or more processors, the memory storing data comprising a database and program code that, when executed by the one or more processors, causes the brake system to:
determine the brake system is operating in a backup mode of operation;
in response to determining the brake system is operating in the backup mode of operation, apply a first brake pressure command to the observer wheel;
monitor a wheel speed of the observer wheel and an actual speed of the vehicle as the first brake pressure command is applied to the observer wheel;
determine that the observer wheel is starting a skid condition based on the wheel speed of the observer wheel and the actual speed of the vehicle, wherein the observer wheel generates an ideal slip value during the skid condition;
in response to determining the observer wheel is starting the skid condition, determine a second brake pressure command based on a target slip value, wherein the target slip value is offset from the ideal slip value and results in a reduced braking efficiency of the brake system; and
apply the second brake pressure command to a remaining portion of the plurality of wheels.

2 . The brake system of claim 1 , wherein the one or more processors execute instructions to:
in response to determining the observer wheel is starting the skid condition, decrease a value of the first brake pressure command.

3 . The brake system of claim 2 , wherein the one or more processors execute instructions to:
continue to decrease the value of the first brake pressure command until the wheel speed of the observer wheel is about equal to the actual speed of the vehicle.

4 . The brake system of claim 1 , wherein the one or more processors execute instructions to:
increase a value of the first brake pressure command while monitoring the wheel speed of the observer wheel and the actual speed of the vehicle.

5 . The brake system of claim 1 , wherein the one or more processors execute instructions to:
determine a reduced second brake pressure command by reducing the second brake pressure command by a parametric confidence value, wherein the parametric confidence value represents one or more varying operating conditions between each of the plurality of wheels.

6 . The brake system of claim 5 , wherein the varying operating conditions include a coefficient of friction along a ground surface, an amount of brake wear, an amount of tire wear, vehicle speed during operation of the brake system, and brake torque gain.

7 . The brake system of claim 1 , wherein the energy storage device is an accumulator, a battery, a capacitor, or a flywheel.

8 . The brake system of claim 1 , wherein the target slip value is a fixed value, wherein the fixed value is based on a type of tire installed on the plurality of wheels.

9 . An aircraft, comprising:
a brake system including a plurality of wheels that designate an observer wheel and an accumulator, wherein the accumulator is configured to store and discharge fluid energy as a pressurized hydraulic brake fluid; one or more processors operatively coupled to the accumulator and in electrical communication with the plurality of wheels; and a memory coupled to the one or more processors, the memory storing data comprising a database and program code that, when executed by the one or more processors, causes the brake system to:
determine the brake system is operating in a backup mode of operation, wherein the backup mode of operation conserves the fluid energy stored in the accumulator;
in response to determining the brake system is operating in the backup mode of operation, apply a first brake pressure command to the observer wheel;
monitor a wheel speed of the observer wheel and an actual speed of the aircraft as the first brake pressure command is applied to the observer wheel;
determine that the observer wheel is starting a skid condition based on the wheel speed of the observer wheel and the actual speed of the aircraft, wherein the observer wheel generates an ideal slip value during the skid condition;
in response to determining the observer wheel is starting the skid condition, determine a second brake pressure command based on a target slip value, wherein the target slip value is offset from the ideal slip value and results in a reduced braking efficiency of the brake system; and
apply the second brake pressure command to a remaining portion of the plurality of wheels.

10 . The aircraft of claim 9 , wherein the one or more processors execute instructions to:
in response to determining the observer wheel is starting the skid condition, decrease a value of the first brake pressure command.

11 . The aircraft of claim 10 , wherein the one or more processors execute instructions to:
continue to decrease the value of the first brake pressure command until the wheel speed of the observer wheel is about equal to the actual speed of the aircraft.

12 . The aircraft of claim 9 , wherein the one or more processors execute instructions to:
increase a value of the first brake pressure command while monitoring the wheel speed of the observer wheel and the actual speed of the aircraft.

13 . The aircraft of claim 9 , wherein the one or more processors execute instructions to:
determine a reduced second brake pressure command by reducing the second brake pressure command by a parametric confidence value, wherein the parametric confidence value represents one or more varying operating conditions between each of the plurality of wheels.

14 . The aircraft of claim 13 , wherein the varying operating conditions include a coefficient of friction along a ground surface, an amount of brake wear, an amount of tire wear, aircraft speed during operation of the brake system, and brake torque gain.

15 . The aircraft of claim 9 , wherein the target slip value is a fixed value, wherein the fixed value is based on a type of tire installed on the plurality of wheels.

16 . A method of controlling a brake system during a backup mode of operation, wherein the brake system includes a plurality of wheels having an observer wheel and energy storage device configured to store and discharge energy, the method comprising:
determining, by a computer, the brake system is operating in a backup mode of operation; in response to determining the brake system is operating in the backup mode of operation, applying a first brake pressure command to the observer wheel; monitoring, by the computer, a wheel speed of the observer wheel and an actual speed of a vehicle as the first brake pressure command is applied to the observer wheel; determining the observer wheel is starting a skid condition based on the wheel speed of the observer wheel and the actual speed of the vehicle, wherein the observer wheel generates an ideal slip value during the skid condition; in response to determining the observer wheel is starting the skid condition, determining a second brake pressure command based on a target slip value, wherein the target slip value is offset from the ideal slip value and results in a reduced braking efficiency of the brake system; and applying the second brake pressure command to a remaining portion of the plurality of wheels.

17 . The method of claim 16 ,

Assignees

• Boeing Co

Inventors

• Forghani Nima
• Yamamoto David T
• Smith Steven Elliot

Classifications

• B64C25/426 Primary

  Braking devices providing an automatic sequence of braking · CPC title

• B60T8/172

  Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters {(B60T8/17551 takes precedence)} · CPC title

• B60T8/17616

  Microprocessor-based systems · CPC title

• B60T2270/10

  ABS control systems · CPC title

• B60T2270/402

  Back-up · CPC title