Wheel deceleration-based antiskid brake controller with adaptive deceleration threshold

• US 6,711,488 B2
• Filed: 05/22/2002
• Issued: 03/23/2004
• Est. Priority Date: 05/22/2002
• Status: Expired due to Term

• Current Assignee: Goodrich Corporation (Rtx Corporation)
• Original Assignee: Goodrich Corporation (Rtx Corporation)
• Inventors: Zierolf, Michael Lee
• Primary Examiner(s): Marc-Coleman, Marthe Y.
• Application Number:
  US10/153,513
• Publication Number:
  US 20030220731A1
• Time in Patent Office: 671 Days
• Field of Search: 701/71, 701/70, 701/75, 701/79, 303/138, 303/139, 303/167, 303/176, 303/126, 303/121
• US Class Current: 701/71
• CPC Class Codes: B60T 8/1703 for aircrafts
• CPC Class Codes: B60T 8/17616 Microprocessor-based systems
• CPC Class Codes: B60T 8/17636 Microprocessor-based systems

Abstract

An antiskid brake controller utilizes measured wheel speed to provide brake control for a vehicles, such as an aircraft. The antiskid brake controller controls a braking operation of a wheel of a vehicle based on a wheel speed signal provided by a wheel speed sensor coupled to the wheel. The antiskid brake controller includes a deceleration threshold generator that selects a deceleration threshold based on the ability of the wheel to hold a pilot commanded brake pressure without excessive skidding. The deceleration threshold is a function of a wheel speed reference signal ω_ref.

Claims

1. An antiskid brake controller for controlling a braking operation of a wheel of a vehicle based on a wheel speed signal provided by a wheel speed sensor coupled to the wheel, the antiskid brake controller comprising:

a deceleration estimator for estimating a deceleration of the wheel based on the wheel speed signal provided by the wheel speed sensor; and

a deceleration threshold generator that selects a deceleration threshold value from a look-up table based on the ability of the wheel to hold a pilot commanded brake pressure without excessive skidding,

the selected deceleration threshold value being summed with the deceleration estimate to produce a control signal for adjusting a brake force applied to the wheel.

2. The controller of claim 1, wherein a selected deceleration threshold value is a function of a wheel speed reference signal ω

_ref.

3. The controller of claim 2, wherein the wheel reference the signal ω

_ref is fed into the deceleration threshold generator to determined the deceleration threshold value based on the desired response characteristics of the antiskid controller.

4. The controller of claim 1, further including:

a reduced integral gain block which outputs a gain that adapts the deceleration threshold to a surface condition by increasing or decreasing the deceleration threshold based on selecting a gain appropriate for the type of surface a wheel is decelerating upon.

5. The controller of claim 1, wherein an output of the antiskid brake controller is used as an upper limit of a limiter of a brake controller in order to prevent damage to a tire.

6. An antiskid brake controller adaptive to a surface condition is provided for controlling a braking operation of a wheel of a vehicle based on a wheel speed signal provided by a wheel speed sensor coupled to the wheel, the antiskid brake controller comprising:

a deceleration estimator for estimating a deceleration of the wheel based on the wheel speed signal provided by the wheel speed sensor;

a deceleration threshold generator that selects a deceleration threshold value based on the ability of the wheel to hold a pilot commanded brake pressure without excessive skidding;

the selected deceleration threshold value is summed with the deceleration estimate to produce a control signal for adjusting a brake force applied to the wheel; and

a reduced integral gain controller for comparing the control signal to a predetermined threshold value to determine the gain to be applied to the control signal,

the gain increasing or decreasing the control signal as a function of the surface condition.

7. The controller of claim 6, wherein the predetermined threshold value indicates a low friction surface has been encountered;

and

the reduced integral gain control block outputs a gain lower than an initial gain wherein the lower gain adapts the antiskid control signal k output of the antiskid brake controller for the low friction surface being encountered.

8. An antiskid brake controller for controlling a braking operation of a wheel of a vehicle based on a wheel speed signal provided by a wheel speed sensor coupled to the wheel, the antiskid brake controller comprising:

a deceleration estimator for estimating a deceleration of the wheel based on the wheel speed signal provided by the wheel speed sensor;

a deceleration threshold generator that provides a deceleration threshold value based on the ability of the wheel to hold a pilot commanded brake pressure without excessive skidding;

the selected deceleration threshold value is summed with the deceleration estimate with to produce a control signal for adjusting a brake force applied to the wheel; and

a proportional gain controller for adding a proportional gain to the control signal;

the proportional gain being added to the control signal to increase a response time of the antiskid brake controller.

9. An antiskid brake controller for controlling a braking operation of a wheel of a vehicle based on a wheel speed signal provided by a wheel speed sensor coupled to the wheel, the antiskid brake controller comprising:

a reset circuit that resets the output of the antiskid controller following a wheel lock-up condition to a percentage less than 100 percent of the output of the antiskid controller prior to the wheel lock-up condition in order to prevent excessive brake pressure from being applied to a wheel.

10. An antiskid brake controller for controlling a braking operation of a wheel of a vehicle based on a wheel speed signal provided by a wheel speed sensor coupled to the wheel, the antiskid brake controller comprising:

a pressure “

dump”

circuit including a normal condition gain input and higher gain input, wherein the higher gain input is used with a wheel speed reference signal ω

_ref following a wheel lock-up condition to determine when to reset the antiskid controller after the wheel lock-up event has occurred, thereby allowing the wheel to spin back up to synchronous before resetting the antiskid controller.

11. The controller of claim 10, wherein the higher gain input is greater than the normal condition gain, but less than “

1”

.