Patent US5014801A successfully refreshed from Google Patents.
US5014801A
Expired / Lapsed
US
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Method and device for rear-wheel steering of automotive vehicle
Assignee: Subaru Corp
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Filing: 1989-02-09
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Granted: 1991-05-14
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Expires: 2009-02-09
Abstract
Abstract In an automotive four-wheel steering system having a control unit for operating in response to various sensors associated with the front-wheel and rear-wheel steering systems to control the steering of the rear wheels. The control unit includes a first sensor for detecting front-wheel steering force or front-wheel assist (power) steering force, or cornering force occurring in the front wheels, a second sensor for detecting front-wheel steering speed, and a sensor abnormality determination device for operating, when a difference occurs between the values detected by the first sensor and the direction of the front-wheel steering speed detected by the second sensor, to indicate that an abnormality has occurred in either of the first or second sensors. Thus fail-safe operation is assured.
Inventors
- 👤 Kenji Hirose
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:52
CPC Classifications
B; B62; B62D; B62D7/00; B62D7/06; B62D7/14; B62D7/148; B62D7/15; B62D7/1581
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
220 words
A method of steering rear wheels for an automotive vehicle having a front-wheel steering system and a rear-wheel steering system, which method comprises: providing a first detection signal indicative of front-wheel steering force; providing a second detection signal indicative of front-wheel steering speed; providing a third detection signal indicative of a rear-wheel steering angle; providing a fourth detection signal indicative of vehicle speed; computing a rear-wheel steering angle reference value and a desired rear-wheel steering speed value based upon said first through fourth detection signals; steering the rear wheels in accordance with said rear-wheel steering angle reference value and said desired rear-wheel steering speed value; detecting whether there is a discrepancy between front-wheel steering force indicated by said first detection signal and front-wheel steering speed indicated by said second detection signal; and determining an abnormality when a discrepancy is detected between said first and second detection signals; said computing step comprising the steps of (a) computing a rear-wheel steering angle reference value from said first and fourth detection signals, (b) computing a first reference value from said second and fourth detection signals, (c) computing a second reference value from said rear-wheel steering angle reference value and said third detection signal, and (d) computing said desired rear-wheel steering speed value based upon said first reference value and said second reference value.
Claim 2
Independent Claim
220 words
A method of steering rear wheels for an automotive vehicle having a front-wheel steering system and a rear-wheel steering system, which method comprises: providing a first detection signal indicative of front-wheel steering force; providing a second detection signal indicative of front-wheel steering speed; providing a third detection signal indicative of a rear-wheel steering angle; providing a fourth detection signal indicative of vehicle speed; computing a rear-wheel steering angle reference value and a desired rear-wheel steering speed value based upon said first through fourth detection signals; steering the rear wheels in accordance with said rear-wheel steering angle reference value and said desired rear-wheel steering speed value; detecting whether there is a discrepancy between front-wheel steering force indicated by said first detection signal and front-wheel steering speed indicated by said second detection signal; and determining an abnormality when a discrepancy is detected between said first and second detection signals; said computing step comprising the steps of (a) computing a rear-wheel steering angle reference value from said first and fourth detection signals, (b) computing a first reference value from said second and fourth detection signals, (c) computing a second reference value from said rear-wheel steering angle reference value and said third detection signal, and (d) computing said desired rear-wheel steering speed value based upon said first reference value and said second reference value.
Claim 3
Dependent Claim
18 words
The method according to claim 1, wherein said first detection signal is indicative of front-wheel steering assist force.
Claim 4
Dependent Claim
22 words
The method according to claim 1, wherein said first detection signal is indicative of cornering force occurring in the vehicle's front wheels.
Claim 5
Dependent Claim
273 words
A rear-wheel steering device for an automotive vehicle having a front-wheel steering system and a rear-wheel steering system which steers the vehicle's rear wheels in accordance with a rear-wheel steering angle reference value and a rear-wheel steering speed value, said device comprising, first means for detecting front-wheel steering force and generating a front-wheel steering force signal indicative thereof; second means for detecting front-wheel steering speed and producing a steering speed signal indicative thereof; third means for detecting a rear-wheel steering angle and providing a rear-wheel steering angle signal indicative thereof; fourth means for detecting vehicle speed and producing a vehicle speed signal indicative thereof; computing means responsive to outputs from said first through forth means for computing a rear-wheel steering angle reference value and a desired rear-wheel steering speed value for said rear-wheel steering system, and abnormality determination means for determining an occurrence of an abnormality in either said first or second means based upon a difference between a front wheel steering force signal from said first means and a front-wheel steering speed signal detected by said second means; said computing means computing (a) a rear-wheel steering angle reference value in response to front-wheel steering force and vehicle speed signals respectively transmitted from said first and fourth means, (b) a first reference value based upon front-wheel steering speed and vehicle speed signals from said second and fourth means, (c) a second reference value based upon said rear-wheel steering angle reference value and a rear wheel steering angle signal from said third means, and (d) a desired rear-wheel steering speed value for said rear-wheel steering system based upon said first and second reference values.
Claim 6
Dependent Claim
273 words
A rear-wheel steering device for an automotive vehicle having a front-wheel steering system and a rear-wheel steering system which steers the vehicle's rear wheels in accordance with a rear-wheel steering angle reference value and a rear-wheel steering speed value, said device comprising, first means for detecting front-wheel steering force and generating a front-wheel steering force signal indicative thereof; second means for detecting front-wheel steering speed and producing a steering speed signal indicative thereof; third means for detecting a rear-wheel steering angle and providing a rear-wheel steering angle signal indicative thereof; fourth means for detecting vehicle speed and producing a vehicle speed signal indicative thereof; computing means responsive to outputs from said first through forth means for computing a rear-wheel steering angle reference value and a desired rear-wheel steering speed value for said rear-wheel steering system, and abnormality determination means for determining an occurrence of an abnormality in either said first or second means based upon a difference between a front wheel steering force signal from said first means and a front-wheel steering speed signal detected by said second means; said computing means computing (a) a rear-wheel steering angle reference value in response to front-wheel steering force and vehicle speed signals respectively transmitted from said first and fourth means, (b) a first reference value based upon front-wheel steering speed and vehicle speed signals from said second and fourth means, (c) a second reference value based upon said rear-wheel steering angle reference value and a rear wheel steering angle signal from said third means, and (d) a desired rear-wheel steering speed value for said rear-wheel steering system based upon said first and second reference values.
Claim 7
Dependent Claim
20 words
The rear-wheel steering device according to claim 4, wherein said first means generates signals indicative of front-wheel steering assist force.
Claim 8
Dependent Claim
24 words
The rear-wheel steering device according to claim 4, wherein said first means generates signals indicative of cornering force occurring in the vehicle's front wheels.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-05-13 | 1994-11-12 | 1995-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-05-13 | 1998-11-12 | 1999-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-05-13 | 2002-11-12 | 2003-05-14 | $7700.00 | Window Closed / Lapsed |