Method of adjustment during stability control of a vehicle

Patent metadata

Field	Value
Publication number	US-12397769-B2
Application number	US-202017001924-A
Country	US
Kind code	B2
Filing date	Aug 25, 2020
Priority date	Sep 18, 2019
Publication date	Aug 26, 2025
Grant date	Aug 26, 2025

Abstract

A method of adjusting test braking pulses during stability control of a vehicle ( 10 ) including the steps of: applying a first test braking pulse to at least one wheel of the vehicle ( 10 ), the application of the test braking pulse comprising operating a brake actuator ( 112 ) to apply a low level braking pressure of the wheel, determining a first longitudinal acceleration (A Long1 ) of the vehicle ( 10 ) during the test braking pulse, obtaining a second longitudinal acceleration (A Long2 ) indicative of the longitudinal acceleration of the vehicle ( 10 ) when a test braking pulse is not being applied, calculating a change in longitudinal acceleration during the test braking pulse, and determining whether the change in longitudinal acceleration is acceptable, and if not, adjusting the level of the braking pressure applied in a subsequent test braking pulse.

First claim

The invention claimed is:

1. A method of adjusting a test braking pulse used for stability control of a vehicle during a subsequent period of rollover assessment of the vehicle, including the steps of:
applying a first test braking pulse to at least one wheel of the vehicle, the application of the test braking pulse comprising operating a brake actuator via an ABS to apply a low level braking pressure of the wheel,
determining a first longitudinal acceleration of the vehicle during the test braking pulse,
obtaining a second longitudinal acceleration indicative of the longitudinal acceleration of the vehicle when the test braking pulse is not being applied, to provide a reference value,
calculating a change in longitudinal acceleration during the test braking pulse by comparing the first longitudinal acceleration against the reference value, and
determining; whether the change in longitudinal acceleration during the test braking pulse is acceptable and if not, adjusting the level of the braking pressure applied in a subsequent test braking pulse;
wherein the step of determining the first longitudinal acceleration includes measuring the longitudinal acceleration of the vehicle over a first predetermined time period and the step of determining the second longitudinal acceleration includes measuring the longitudinal acceleration of the vehicle over a second predetermined time period, wherein the second predetermined time period over which the second longitudinal acceleration is measured is longer than the first predetermined time period over which the first longitudinal acceleration is measured such that the second longitudinal acceleration defines the reference value to assist in comparing the first longitudinal acceleration against the reference value while calculating the change in longitudinal acceleration for the rollover assessment.

2. A method of adjusting a test braking pulse according to claim 1 wherein the step of obtaining the second longitudinal acceleration includes a step of determining the longitudinal acceleration either before or after the test braking pulse has been applied.

3. A method of adjusting a test braking pulse according to claim 2 wherein the step of determining the second longitudinal acceleration is performed within Is of the test braking pulse being applied.

4. A method of adjusting a test braking pulse according to claim 2 wherein the step of determining the second longitudinal acceleration includes calculating an average longitudinal acceleration over the second predetermined time period.

5. A method of adjusting a test braking pulse according to claim 4 wherein the second predetermined time period is between 200 ms and 800 ms.

6. A method of adjusting a test brake pulse according to claim 5 , where the second time period is 600 ms.

7. A method of adjusting a test braking pulse according to claim 2 wherein the first predetermined time period over which the first longitudinal acceleration is measured is between 200 ms and 800 ms.

8. A method of adjusting a test brake pulse according to claim 7 , wherein the first predetermined time is 400 ms.

9. A method of adjusting a test braking pulse according to claim 2 wherein the step of determining the second longitudinal acceleration includes applying a filter to the measurement taken over the second predetermined time period.

10. A method of adjusting a test braking pulse according to claim 1 further including a test pulse phase which includes applying multiple test braking pulses in a predetermined sequence.

11. A method of adjusting a test braking pulse according to claim 10 wherein if an adjustment to the test braking pulse is required, the adjustment is made at a predetermined position in the sequence and/or at the end of the test pulse phase.

12. A method of adjusting a test braking pulse according to claim 1 wherein an acceptable change in longitudinal acceleration is within a predetermined range or by comparison to a predetermined threshold.

13. A method of adjusting a test braking pulse according to claim 12 wherein if the modulus of the change in longitudinal acceleration is above the predetermined range or above the predetermined threshold, the test braking pulse is adjusted to a lower level.

14. A method of adjusting a test braking pulse according to claim 12 wherein if the modulus of the change in longitudinal acceleration is below the predetermined range or below the predetermined threshold, the test braking pulse is adjusted to a higher level.

15. A method of carrying out stability control of a vehicle including using the method of claim 1 and further including the steps of:
measuring a lateral acceleration of the vehicle to determine a side of the vehicle on the inside of a turn,
applying the first test braking pulse to a wheel on the inside of the vehicle,
measuring the rotational speed of the wheel during the test braking pulse, calculating a change in rotational speed of the wheel during the test braking pulse, and performing a stability control intervention if the change in rotational speed of the wheel is above a predetermined threshold.

16. A method of carrying out stability control of a vehicle using the method of claim 1 and further including the steps of:
applying the first test braking pulse to a wheel on a first side of the vehicle and a second test braking pulse to a wheel on a second, opposite, side of the vehicle, measuring a change in the rotational speed of both wheels during the test braking pulse, calculating the difference between the change in rotational speed of the wheel on the first side and the change in rotational speed of the wheel on the second side of the vehicle, and
performing a stability control intervention if the difference is above a predetermined threshold.

17. A method of carrying out stability control of a vehicle according to claim 15 wherein the method of adjusting the test braking pulses is implemented concurrently with the step of applying the test braking pulse to the wheel of the vehicle.

18. A system that is operable to perform the method of adjusting test braking pulses according to claim 1 .

Assignees

• Haldex Brake Prod Ab

Inventors

• Harrison Dudley

Classifications

• B60T8/171

  Detecting parameters used in the regulation; Measuring values used in the regulation · CPC title

• B60T2250/04

  Vehicle reference speed; Vehicle body speed · CPC title

• B60T2270/406

  Test-mode; Self-diagnosis · CPC title

• B60T8/1755

  Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve (road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02) · CPC title

• B60T2270/313

  with less than three sensors (yaw rate, steering angle, lateral acceleration) · CPC title