Wheel speed averaging circuit

• US 6,021,382 A
• Filed: 02/12/1998
• Issued: 02/01/2000
• Est. Priority Date: 02/12/1998
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Greenwell, Randall Glenn, Drauch, Douglas Robert
• Primary Examiner(s): ASSOUAD, PATRICK J
• Application Number:
  US09/022,434
• Time in Patent Office: 719 Days
• Field of Search: 702/148, 702/146, 180/197, 180/248, 701/70, 701/71, 701/51, 701/82, 701/93, 235/61 E
• US Class Current: 702/148
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence

Abstract

A wheel speed averaging circuit includes a first wheel speed sensor, a second wheel speed sensor, a first analog switch having a first input coupled to the first wheel speed sensor for receiving the first sensor signal, a second analog switch having a second input coupled to the second wheel speed sensor for receiving the second sensor signal, and a microprocessor controller. The microprocessor controller determines a first duration of a first single pulse of the first sensor signal while the first analog switch is enabled and the second analog switch is disabled, selectively enables the second analog switch while disabling the first analog switch after determining the first duration, and determines a second duration of a second single pulse of the second sensor signal while the second analog switch is enabled, so that the first and second single pulses from the first and second sensor signals are alternately measured. The rear average wheel speed signal is provided responsive to the first and second durations.

Claims

1. A wheel speed averaging circuit comprising:

a first wheel speed sensor providing a first sensor signal indicative of a first rotational velocity of a first wheel;

a second wheel speed sensor providing a second sensor signal indicative of a second rotational velocity of a second wheel;

a first analog switch having a first input coupled to the first wheel speed sensor for receiving the first sensor signal;

a second analog switch having a second input coupled to the second wheel speed sensor for receiving the second sensor signal;

a microprocessor controller coupled to first and second outputs of the first and second analog switches, respectively, wherein the microprocessor controller comprises

(a) means for determining a first duration of a first single pulse of the first sensor signal while the first analog switch is enabled and the second analog switch is disabled,

(b) means for selectively enabling the second analog switch while disabling the first analog switch after determining the first duration of the first single pulse,

(c) means for determining a second duration of a second single pulse of the second sensor signal while the second analog switch is enabled,

(d) means for selectively enabling the first analog switch while disabling the second analog switch after determining the second duration of the second single pulse, wherein the first and second single pulses from the first and second sensor signals are alternately measured, and

(e) means for providing a speed signal indicative of an average speed of the first and second wheels responsive to the first and second durations.

2. A wheel speed averaging circuit according to claim 1, wherein the first and second analog switches are enabled for equal time periods unless first or second pulses are received.