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Position and direction determination using multiple single-channel encoders

  • US 8,965,691 B1
  • Filed: 10/05/2012
  • Issued: 02/24/2015
  • Est. Priority Date: 10/05/2012
  • Status: Active Grant
First Claim
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1. A method comprising:

  • determining a low speed condition based on a decreasing velocity of a vehicle;

    in response to the low speed condition, receiving, by a computing system, a first data stream from a first single channel encoder associated with a first wheel of the vehicle, the first data stream indicative of a first regularly repeating pattern with a frequency based on a rate of rotation of the first wheel;

    receiving, by the computing system, a second data stream from a second single channel encoder associated with a second wheel of the vehicle, the second data stream indicative of a second regularly repeating pattern with a frequency based on a rate of rotation of the second wheel;

    characterizing a time series relationship between the first and second regularly repeating patterns during a first time window corresponding to motion of the vehicle in a first direction;

    during a second time window following the first time window, identifying a shift in the characterized time series relationship corresponding to a reversal in rotation direction of the first and second wheels;

    responsive to identifying the shift, determining the vehicle is moving in a second direction substantially opposite the first direction; and

    determining a time of direction reversal of the vehicle based on a timing of the identified shift.

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