Method for determining the gradient of a roadway

Patent 5797109 Issued on August 18, 1998. Estimated Expiration Date:

December 7, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Patent #: 4352405
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Inventors

Assignee

Mercedes-Benz AG

Application

No. 568447 filed on 12/07/1995

US Classes:

701/65, Responsive to road, external, or ambient condition701/80Having coefficient of friction or road condition determining means

Examiners

Primary: Nguyen, Tan T.
Assistant: Pipala, Edward

Attorney, Agent or Firm

Evenson, McKeown Edwards & Lenahan, P.L.L.C.

Foreign Patent References

43 08 128 DE. 06/13/1994

International Class

G01C 009/06

Foreign Application Priority Data

1994-12-07 DE

Abstract

The gradient of a roadway in the direction of travel of the vehicle is identified from signals present in the vehicle without any additional sensor systems. A freely rolling state of the at least one driven axle of the vehicle is detected at least once. In this state, the wheels of the driven axle also roll free of slip. In order to balance out the wheel speeds between the driven axles and the non-driven axles, the difference speed between the wheel speed of a driven axle and the wheel speed of a non-driven axle is identified. At the same time, the value of the braking, that is to say the value of the deceleration of the vehicle, is measured. The value of a gradient constant is identified from the identified values of the difference speeds and the braking operations. The gradient of the roadway can be determined with the gradient constant from the values of the difference speed and the values of the braking then identified. The gradient information can then be used to control the vehicle.