Wheel diameter calibration system for vehicle slip/slide control

• US 6,148,269 A
• Filed: 07/20/1998
• Issued: 11/14/2000
• Est. Priority Date: 07/20/1998
• Status: Expired due to Term

• Current Assignee: GE Global Sourcing LLC (Westinghouse Air Brake Technologies Corporation)
• Original Assignee: General Electric Company
• Inventors: Kumar, Ajith Kuttannair, Worden, Bret Dwayne
• Primary Examiner(s): NOLAND, THOMAS
• Application Number:
  US09/118,875
• Time in Patent Office: 848 Days
• Field of Search: 105/444, 105/96, 180/209, 702/96, 701/19, 701/20, 701/82, 701/88, 701/89, 701/91
• US Class Current: 702/96
• CPC Class Codes: B60T 2240/08 Spare wheel detection; Adjusting brake control in case of spare wheel use
• CPC Class Codes: B60T 2270/416 Wheel speed sensor failure
• CPC Class Codes: B60T 8/173 Eliminating or reducing the effect of unwanted signals, e.g. due to vibrations or electrical noise
• CPC Class Codes: B60T 8/885 using electrical circuitry
• CPC Class Codes: B61C 15/14 controlling distribution of tractive effort between driving wheels

Abstract

A method and apparatus for wheel diameter calibration in a vehicle of the type having a plurality of independently powered wheel-axle sets which can be implemented as a forced calibration while the vehicle is in either a tractive effort or an electrical braking mode. The process includes the steps of determining if vehicle tractive effort would be effected if one wheel-axle set were disabled and, if not, selectively disabling one of the wheel-axle sets, calculating vehicle speed from a present value of wheel diameter for the disabled axle and wheel revolutions per unit time, establishing a true value of vehicle speed from an independent measurement, computing the error between calculated vehicle speed and the true value of vehicle speed, and adjusting the present value of wheel diameter so as to minimize the computed speed error.

Claims

1. A method for wheel diameter calibration in a vehicle of the type having a plurality of independently powered wheel-axle sets, the method comprising the steps of:

determining if vehicle tractive effort would be effected if one wheel-axle set were disabled and, if not, selectively disabling one of the wheel-axle sets;

calculating vehicle speed from a present value of wheel diameter for the disabled axle and wheel revolutions per unit time;

establishing a true value of vehicle speed from an independent measurement;

computing the error between calculated vehicle speed and the true value of vehicle speed; and

adjusting the present value of wheel diameter so as to minimize the computed speed error.

2. The method of claim 1 wherein the step of determining comprises the steps of:

evaluating whether the rate of change of vehicle speed is less than a selected value for a selected time interval;

confirming that vehicle speed is greater than a selected minimum value; and

assuring that the vehicle is not operating in an air brake mode, the electrical braking effort is less than a selected maximum value and that commanded tractive effort or horsepower is less than a selected maximum value.

3. The method of claim 2 wherein the selected value of rate of change of speed is 0.25 MPH/SEC for at least 0.5 seconds.

4. The method of claim 2 wherein the selected maximum value of commanded tractive effort or horsepower is less than notch 7 in a system having power settings from notch 1 to notch 8.

5. The method of claim 2 wherein the step of adjusting the value of wheel diameter requires the preliminary steps of confirming that vehicle torque is less than a selected maximum torque, that vehicle speed is greater than a selected minimum speed, that the speed sensors are operational and that the computed error is greater than about one per cent.

6. The method of claim 5 wherein the step of adjusting comprises the step of integrating the speed error value to produce a value of wheel diameter.

7. The method of claim 6 and including the step of modifying the speed error value in a manner to affect a faster time constant for reaching a final value of wheel diameter.