Vehicle control apparatus

• US 8,380,395 B2
• Filed: 09/10/2010
• Issued: 02/19/2013
• Est. Priority Date: 09/16/2009
• Status: Expired due to Fees

• Current Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: Kashiwamura, Satoshi, Shimizu, Hiroyuki
• Primary Examiner(s): FREJD, RUSSELL WARREN
• Application Number:
  US12/879,172
• Publication Number:
  US 20110066326A1
• Time in Patent Office: 893 Days
• Field of Search: 701 36- 39, 73/110.4, 280/5.5, 280 5505- 5507, 280/5.515, 188/280, 188/281
• US Class Current: 701/38
• CPC Class Codes: B60G 17/0164 mainly during accelerating or braking
• CPC Class Codes: B60G 17/018 characterised by the use of a specific signal treatment or control method
• CPC Class Codes: B60G 17/0195 characterised by the regulation being combined with other vehicle control systems conjoint control of vehicle sub-units including control of suspension systems B60W10/22
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/208 of wheel rotation
• CPC Class Codes: B60G 2400/50 Pressure
• CPC Class Codes: B60G 2500/106 duty rate
• CPC Class Codes: B60G 2800/215 by applying a braking action on each wheel individually
• CPC Class Codes: B60G 2800/94 Electronic Stability Program (ESP, i.e. ABS+ASC+EMS)
• CPC Class Codes: B60T 2260/06 Active Suspension System
• CPC Class Codes: B60T 8/17616 Microprocessor-based systems
• CPC Class Codes: B60W 10/188 hydraulic brakes
• CPC Class Codes: B60W 10/22 including control of suspension systems
• CPC Class Codes: B60W 2510/182 Brake pressure, e.g. of fluid or between pad and disc
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 30/18109 Braking
• CPC Class Codes: B60W 30/18172 Preventing, or responsive to skidding of wheels

Abstract

A vehicle control apparatus including a road wheel speed detecting section, a vehicle body speed detecting section, a slip ratio calculating section configured to calculate slip ratios which are ratios of respective road wheel speeds with respect to vehicle body speed, an anti-skid brake control section configured to control wheel cylinder fluid pressures for respective wheel cylinders such that the slip ratios fall within a predetermined range, a wheel cylinder fluid pressure acquiring section, damping force variable shock absorbers which are disposed between the respective road wheels and the vehicle body and constructed to variably adjust respective damping force characteristics thereof, and a damping force variable shock absorber control section configured to set the damping force characteristics in accordance with the acquired wheel cylinder fluid pressures.

Claims

1. A vehicle control apparatus comprising:

a road wheel speed detecting section configured to detect road wheel speeds of respective road wheels of a vehicle;

a vehicle body speed detecting section configured to detect a vehicle body speed;

a slip ratio calculating section configured to calculate slip ratios which are ratios of the respective road wheel speeds with respect to the vehicle body speed;

an anti-skid brake control section configured to control wheel cylinder fluid pressures for respective wheel cylinders such that the slip ratios fall within a predetermined range;

a wheel cylinder fluid pressure acquiring section configured to acquire the wheel cylinder fluid pressures;

damping force variable shock absorbers disposed between the respective road wheels and the vehicle body, the damping force variable shock absorbers being constructed to variably adjust respective damping force characteristics thereof; and

a damping force variable shock absorber control section configured to set the damping force characteristics in accordance with the acquired wheel cylinder fluid pressures.

2. The vehicle control apparatus as claimed in claim 1, wherein the damping force variable shock absorber control section is configured to set the damping force characteristics to harder damping force characteristics as the acquired wheel cylinder fluid pressures become higher.

3. The vehicle control apparatus as claimed in claim 2, wherein the damping force variable shock absorber control section is configured such that when the wheel cylinder fluid pressures are reduced under a condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control section, the damping force characteristics are set in accordance with the wheel cylinder fluid pressures at a time at which reduction of the wheel cylinder fluid pressures is started.

4. The vehicle control apparatus as claimed in claim 3, wherein the damping force variable shock absorber control section is configured to keep the set damping force characteristics until next reduction of the wheel cylinder fluid pressures is started by the anti-skid brake control section.

5. The vehicle control apparatus as claimed in claim 2, wherein the damping force variable shock absorber control section is configured such that when the wheel cylinder fluid pressures are increased under a condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control section, in a case where the acquired wheel cylinder fluid pressures are lower than the wheel cylinder fluid pressures set at a time at which preceding reduction of the wheel cylinder fluid pressures is started, the damping force characteristics are set in accordance with the wheel cylinder fluid pressures set at the time at which preceding reduction of the wheel cylinder fluid pressures is started.

6. The vehicle control apparatus as claimed in claim 2, further comprising a wheel cylinder fluid pressure correction value calculating section,

wherein the wheel cylinder fluid pressure correction value calculating section is configured such that under a condition that the wheel cylinder fluid pressures are not controlled by the anti-skid brake control section, wheel cylinder fluid pressure correction values are set to the acquired wheel cylinder fluid pressures, and the wheel cylinder fluid pressure correction value calculating section is configured such that when the wheel cylinder fluid pressures are reduced under a condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control section, the wheel cylinder fluid pressure correction values are set to the wheel cylinder fluid pressures at a time at which reduction of the wheel cylinder fluid pressures is started, and

wherein the damping force variable shock absorber control section is configured to set the damping force characteristics in accordance with the wheel cylinder fluid pressure correction values.

7. The vehicle control apparatus as claimed in claim 6, wherein the damping force variable shock absorber control section is configured to set the damping force characteristics to harder damping force characteristics as the wheel cylinder fluid pressure correction values become higher.

8. The vehicle control apparatus as claimed in claim 2, further comprising a wheel cylinder fluid pressure correction value calculating section,

wherein the wheel cylinder fluid pressure correction value calculating section is configured such that when the wheel cylinder fluid pressures are increased under the condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control section, in a case where the acquired wheel cylinder fluid pressures are lower than the wheel cylinder fluid pressures set at a time at which preceding reduction of the wheel cylinder fluid pressures is started, wheel cylinder fluid pressure correction values are set to the wheel cylinder fluid pressures set at the time at which preceding reduction of the wheel cylinder fluid pressures is started, and the wheel cylinder fluid pressure correction value calculating section is configured such that when the wheel cylinder fluid pressures are increased under the condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control section, in a case where the acquired wheel cylinder fluid pressures are not lower than the wheel cylinder fluid pressures set at the time at which preceding reduction of the wheel cylinder fluid pressures is started, the wheel cylinder fluid pressure correction values are set to the acquired wheel cylinder fluid pressures, and

wherein the damping force variable shock absorber control section is configured to set the damping force characteristics in accordance with the wheel cylinder fluid pressure correction values.

9. The vehicle control apparatus as claimed in claim 8, wherein the damping force variable shock absorber control section is configured to set the damping force characteristics to harder damping force characteristics as the wheel cylinder fluid pressure correction values become higher.

10. The vehicle control apparatus as claimed in claim 9, wherein the wheel cylinder fluid pressure correction values are set corresponding to values of friction coefficient μ

of a road surface on which the vehicle is running.

11. A vehicle control apparatus comprising:

road wheel speed sensors which detect road wheel speeds of respective road wheels of a vehicle;

a vehicle body speed calculating section configured to calculate a vehicle body speed on the basis of the detected road wheel speeds;

a slip ratio calculating section configured to calculate slip ratios which are ratios of the respective road wheel speeds with respect to the vehicle body speed;

an anti-skid brake control section configured to control wheel cylinder fluid pressures for respective wheel cylinders such that the slip ratios fall within a predetermined range;

a wheel cylinder fluid pressure acquiring section configured to acquire the wheel cylinder fluid pressures;

a wheel cylinder fluid pressure correction value calculating section configured to correct the acquired wheel cylinder fluid pressures in accordance with an operating state of the anti-skid brake control section;

damping force variable shock absorbers disposed between the respective road wheels and the vehicle body, the damping force variable shock absorbers being constructed to variably adjust respective damping force characteristics thereof; and

a damping force variable shock absorber control section configured to set the damping force characteristics in accordance with wheel cylinder fluid pressure correction values obtained as the corrected wheel cylinder fluid pressures.

12. The vehicle control apparatus as claimed in claim 11, wherein the damping force variable shock absorber control section is configured to set the damping force characteristics to harder damping force characteristics as the wheel cylinder fluid pressure correction values become higher, and set the damping force characteristics to softer damping force characteristics as the wheel cylinder fluid pressure correction values become lower.

13. The vehicle control apparatus as claimed in claim 12, wherein the wheel cylinder fluid pressure correction value calculating section is configured such that when the wheel cylinder fluid pressures are increased under a condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control section, in a case where the acquired wheel cylinder fluid pressures are lower than the wheel cylinder fluid pressures set at a time at which preceding reduction of the wheel cylinder fluid pressures is started, the wheel cylinder fluid pressure correction values are set to the wheel cylinder fluid pressures set at the time at which preceding reduction of the wheel cylinder fluid pressures is started, and the wheel cylinder fluid pressure correction value calculating section is configured such that when the wheel cylinder fluid pressures are increased under the condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control section, in a case where the acquired wheel cylinder fluid pressures are not lower than the wheel cylinder fluid pressures set at the time at which preceding reduction of the wheel cylinder fluid pressures is started, the wheel cylinder fluid pressure correction values are set to the acquired wheel cylinder fluid pressures.

14. The vehicle control apparatus as claimed in claim 13, wherein the wheel cylinder fluid pressure correction value calculating section is configured such that when the wheel cylinder fluid pressures are reduced under a condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control section, the wheel cylinder fluid pressure correction values are set to the wheel cylinder fluid pressures at a time at which reduction of the wheel cylinder fluid pressures is started.

15. The vehicle control apparatus as claimed in claim 14, wherein the wheel cylinder fluid pressure correction value calculating section is configured to keep the wheel cylinder fluid pressure correction values until next reduction of the wheel cylinder fluid pressures is started by the anti-skid brake control section.

16. The vehicle control apparatus as claimed in claim 15, wherein the wheel cylinder fluid pressure correction values are set corresponding to values of friction coefficient μ

of a road surface on which the vehicle is running.

17. A vehicle control apparatus comprising:

a road wheel speed detecting means for detecting road wheel speeds of respective road wheels of a vehicle;

a vehicle body speed detecting means for detecting a vehicle body speed;

a slip ratio calculating means for calculating slip ratios which are ratios of the respective road wheel speeds with respect to the vehicle body speed;

an anti-skid brake control means for controlling wheel cylinder fluid pressures for respective wheel cylinders such that the slip ratios fall within a predetermined range;

a wheel cylinder fluid pressure acquiring means for acquiring the wheel cylinder fluid pressures;

damping force variable shock absorbers disposed between the respective road wheels and the vehicle body, the damping force variable shock absorbers being constructed to variably adjust respective damping force characteristics thereof; and

a damping force variable shock absorber control means for setting the damping force characteristics to harder damping force characteristics as the acquired wheel cylinder fluid pressures become higher.

18. The vehicle control apparatus as claimed in claim 17, wherein the damping force variable shock absorber control means operates to set the damping force characteristics to softer damping force characteristics as the acquired wheel cylinder fluid pressures become lower.

19. The vehicle control apparatus as claimed in claim 18, wherein the damping force variable shock absorber control means operates such that when the wheel cylinder fluid pressures are reduced under a condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control means, the damping force characteristics are set in accordance with the wheel cylinder fluid pressures at a time at which reduction of the wheel cylinder fluid pressures is started, and

the damping force variable shock absorber control means operates such that when the wheel cylinder fluid pressures are increased under the condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control means, in a case where the acquired wheel cylinder fluid pressures are lower than wheel cylinder fluid pressures set at a time at which preceding reduction of the wheel cylinder fluid pressures is started, the damping force characteristics are set in accordance with the wheel cylinder fluid pressures set at the time at which preceding reduction of the wheel cylinder fluid pressures is started.

20. The vehicle control apparatus as claimed in claim 19, further comprising a wheel cylinder fluid pressure correction value calculating means for calculating wheel cylinder fluid pressure correction values for the respective wheel cylinders, wherein the wheel cylinder fluid pressure correction value calculating means operates such that under a condition that the wheel cylinder fluid pressures are not controlled by the anti-skid brake control means, the wheel cylinder fluid pressure correction values are set to the acquired wheel cylinder fluid pressures,

the wheel cylinder fluid pressure correction value calculating means operates such that when the wheel cylinder fluid pressures are reduced under the condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control means, the wheel cylinder fluid pressure correction values are set to the wheel cylinder fluid pressures at the time at which reduction of the wheel cylinder fluid pressures is started, and

the wheel cylinder fluid pressure correction value calculating means operates such that when the wheel cylinder fluid pressures are increased under the condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control means, in a case where the acquired wheel cylinder fluid pressures are lower than the wheel cylinder fluid pressures set at the time at which preceding reduction of the wheel cylinder fluid pressures is started, the wheel cylinder fluid pressure correction values are set to the wheel cylinder fluid pressures set at the time at which preceding reduction of the wheel cylinder fluid pressures is started, and the wheel cylinder fluid pressure correction value calculating means operates such that when the wheel cylinder fluid pressures are increased under the condition that the wheel cylinder fluid pressures are controlled by the anti-skid brake control means, in a case where the acquired wheel cylinder fluid pressures are not lower than the wheel cylinder fluid pressures set at the time at which preceding reduction of the wheel cylinder fluid pressures is started, the wheel cylinder fluid pressure correction values are set to the acquired wheel cylinder fluid pressures, and

wherein the damping force variable shock absorber control means operates to set the damping force characteristics to harder damping force characteristics as the wheel cylinder fluid pressure correction values become higher.