US5488555A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for four wheel steering control
Assignee: MID-AMERICA COMMERCILIZATION Corp A KANSAS CORP
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Filing: 1993-05-27
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Granted: 1996-01-30
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Expires: 2013-05-27
Abstract
Abstract Method, for use in a vehicle including a four wheel steering system and an electronic control unit having memory, of controlling the four wheel steering system while at least one of the wheels is under a torque load such that the vehicle behaves like a front wheel steering vehicle under no torque load, or a four wheel steering vehicle under no torque load. The method includes determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load, and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface. Apparatus is provided for carrying out the method.
Inventors
- 👤 Jahanbakhsh Asgari
- 👤 Minh N. Tran
- 👤 Davorin D. Hrovat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:21
CPC Classifications
B; B62; B62D; B62D7/00; B62D7/06; B62D7/14; B62D7/15; B62D7/159; B60; B60T; B60T2260/00; B60T2260/02; B60T2260/022; B60W; B60W50/00; B60W2050/0001; B60W2050/0019; B60W2050/0028; B60W2050/0031; B60W2520/00; B60W2520/14
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
161 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; the proportional steer control gain K p for a rear wheel drive vehicle being determined according to: ##EQU35##
Claim 2
Dependent Claim
161 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; the proportional steer control gain K p for a rear wheel drive vehicle being determined according to: ##EQU35##
Claim 3
Dependent Claim
258 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; determining the front wheel tire steering angle, the step of controlling the four wheel steering system including steering the rear wheels based on the proportional steer control gain, the yaw rate control gain and the front tire steering angle; storing a plurality of yaw rate control gain and proportional steer control gain pairs in said memory; determining percent slip of the rear wheels in relation to the road surface; and retrieving a control gain pair from the memory based on the percent slip of the rear wheels for controlling the four wheel steering system; the proportional steer control gain K p for a front wheel drive vehicle having a desired yaw-rate being determined according to: ##EQU36##
Claim 4
Dependent Claim
258 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; determining the front wheel tire steering angle, the step of controlling the four wheel steering system including steering the rear wheels based on the proportional steer control gain, the yaw rate control gain and the front tire steering angle; storing a plurality of yaw rate control gain and proportional steer control gain pairs in said memory; determining percent slip of the rear wheels in relation to the road surface; and retrieving a control gain pair from the memory based on the percent slip of the rear wheels for controlling the four wheel steering system; the proportional steer control gain K p for a front wheel drive vehicle having a desired yaw-rate being determined according to: ##EQU36##
Claim 5
Dependent Claim
166 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; the proportional steer control gain K p for a front wheel drive vehicle having a desired lateral velocity being determined according to: ##EQU37##
Claim 6
Dependent Claim
166 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; the proportional steer control gain K p for a front wheel drive vehicle having a desired lateral velocity being determined according to: ##EQU37##
Claim 7
Dependent Claim
183 words
For use with an automotive vehicle including four wheels and a four wheel steering system controlled by an electronic control unit having memory, the four wheel steering system for steering the four wheels while at least one of the wheels is under a torque load, the steering system further comprising: means for determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; and means for controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the means for determining at least one control gain including means for determining a yaw rate control gain based on vehicle stability requirements, the means for determining at least one control gain further comprising means for determining a proportional steer control gain based on the yaw rate control gain; the means for determining a proportional steer control gain effecting proportional steer control gain (K p ) for a rear wheel drive vehicle according to: ##EQU38##
Claim 8
Dependent Claim
183 words
For use with an automotive vehicle including four wheels and a four wheel steering system controlled by an electronic control unit having memory, the four wheel steering system for steering the four wheels while at least one of the wheels is under a torque load, the steering system further comprising: means for determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; and means for controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the means for determining at least one control gain including means for determining a yaw rate control gain based on vehicle stability requirements, the means for determining at least one control gain further comprising means for determining a proportional steer control gain based on the yaw rate control gain; the means for determining a proportional steer control gain effecting proportional steer control gain (K p ) for a rear wheel drive vehicle according to: ##EQU38##
Claim 9
Dependent Claim
181 words
For use with an automotive vehicle including four wheels and a four wheel steering system controlled by an electronic control unit having memory for steering the four wheels while at least one of the wheels is under a torque load, the steering system comprising: means for determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; and means for controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the means for determining at least one control gain including means for determining a yaw rate control gain based on vehicle stability requirements, the means for determining at least one control gain further comprising means for determining a proportional steer control gain based on the yaw rate control gain; the means for determining a proportional steer control gain K p determining the proportional steer control gain for a front wheel drive vehicle having a desired yaw-rate according to: ##EQU39##
Claim 10
Dependent Claim
181 words
For use with an automotive vehicle including four wheels and a four wheel steering system controlled by an electronic control unit having memory for steering the four wheels while at least one of the wheels is under a torque load, the steering system comprising: means for determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; and means for controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the means for determining at least one control gain including means for determining a yaw rate control gain based on vehicle stability requirements, the means for determining at least one control gain further comprising means for determining a proportional steer control gain based on the yaw rate control gain; the means for determining a proportional steer control gain K p determining the proportional steer control gain for a front wheel drive vehicle having a desired yaw-rate according to: ##EQU39##
Claim 11
Dependent Claim
183 words
For use with an automotive vehicle including four wheels and a four wheel steering system controlled by an electronic control unit having memory for steering the four wheels while at least one of the wheels is under a torque load, the steering system further comprising: means for determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; and means for controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the means for determining at least one control gain including means for determining a yaw rate control gain based on vehicle stability requirements, the means for determining at least one control gain further comprising means for determining a proportional steer control gain based on the yaw rate control gain; the means for determining the proportional steer control gain K p determining the proportional steer control gain for a front wheel drive vehicle having a desired lateral velocity according to: ##EQU40##
Claim 12
Dependent Claim
183 words
For use with an automotive vehicle including four wheels and a four wheel steering system controlled by an electronic control unit having memory for steering the four wheels while at least one of the wheels is under a torque load, the steering system further comprising: means for determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a front wheel steering vehicle under no torque load; and means for controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the means for determining at least one control gain including means for determining a yaw rate control gain based on vehicle stability requirements, the means for determining at least one control gain further comprising means for determining a proportional steer control gain based on the yaw rate control gain; the means for determining the proportional steer control gain K p determining the proportional steer control gain for a front wheel drive vehicle having a desired lateral velocity according to: ##EQU40##
Claim 13
Dependent Claim
161 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a four wheel steering vehicle under no torque load; and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; the proportional steer control gain K p for a rear wheel drive vehicle being determined according to: ##EQU41##
Claim 14
Dependent Claim
161 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a four wheel steering vehicle under no torque load; and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; the proportional steer control gain K p for a rear wheel drive vehicle being determined according to: ##EQU41##
Claim 15
Dependent Claim
165 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a four wheel steering vehicle under no torque load; and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; the proportional steer control gain K p for a front wheel drive vehicle having a desired yaw-rate being determined according to: ##EQU42##
Claim 16
Dependent Claim
165 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a four wheel steering vehicle under no torque load; and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; the proportional steer control gain K p for a front wheel drive vehicle having a desired yaw-rate being determined according to: ##EQU42##
Claim 17
Dependent Claim
165 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a four wheel steering vehicle under no torque load; and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; the proportional steer control gain K p for a front wheel drive vehicle having a desired lateral velocity determined according to: ##EQU43##
Claim 18
Dependent Claim
165 words
For use in a vehicle including front wheels, rear wheels, a four wheel steering system and an electronic control unit having memory, a method of controlling the four wheel steering system comprising: applying a torque load to at least one of the vehicle wheels; determining at least one control gain for the four wheel steering system so that the torque loaded vehicle behaves like a four wheel steering vehicle under no torque load; and controlling the four wheel steering system according to the control gain, thereby improving directional stability of the vehicle travelling on a slippery road surface; the step of determining at least one control gain comprising determining a yaw rate control gain based on vehicle stability requirements, the step of determining at least one control gain further comprising determining a proportional steer control gain based on the yaw rate control gain; the proportional steer control gain K p for a front wheel drive vehicle having a desired lateral velocity determined according to: ##EQU43##
References Cited (Backward Citations)
US4042059A
Cited
US4651290A
Cited
US5010971A
Cited
US4964481A
Cited
US5116254A
Cited
US4679808A
Cited
US4767588A
Cited
US4740002A
Cited
US4874056A
Cited
US4895383A
Cited
US4913250A
Cited
US4941095A
Cited
US4951198A
Cited
US5002147A
Cited
US4967865A
Cited
US5040115A
Cited
US4842089A
Cited
US4828061A
Cited
US4989686A
Cited
US5019982A
Cited
US5119298A
Cited
US5088040A
Cited
US5048633A
Cited
US4986388A
Cited
US5035295A
Cited
US5099940A
Cited
US5103925A
Cited
US4947332A
Cited
US5212642A
Cited
US5251719A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-01-29 | 1999-07-31 | 2000-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-29 | 2003-07-31 | 2004-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-29 | 2007-07-31 | 2008-01-30 | $7700.00 | Window Closed / Lapsed |