Method and apparatus for providing accurate localization for an industrial vehicle

  • US 8,655,588 B2
  • Filed: 11/18/2011
  • Issued: 02/18/2014
  • Est. Priority Date: 05/26/2011
  • Status: Active Grant
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First Claim
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1. A method of operating an industrial vehicle in a physical environment, wherein:

  • the industrial vehicle comprises a mobile computer and a plurality of sensor devices;

    the plurality of sensor devices comprise a wheel encoder, an IMU, or both, and one or more two-dimensional laser scanners;

    the wheel encoder, IMU, or both, provide odometry data of the industrial vehicle;

    the two-dimensional laser scanner provides details of the physical environment;

    the mobile computer comprises an EBN module that employs a priority queue that receives input messages from the plurality of sensor devices and associates each input message with a data source and an acquisition time stamp;

    the plurality of sensor devices have different sampling periods and different sampling delays so that an order in which sensor data from the plurality of sensor devices is acquired is not the same as an order in which the sensor data becomes available to the EBN module;

    the industrial vehicle is moved along a vehicle path by utilizing an Extended Kalman Filter of the mobile computer to model the position of the industrial vehicle in a two-dimensional plane as a probability density, use the odometry data to update a predicted position of the industrial vehicle, and correct for error in the predicted position of the industrial vehicle using environmental features extracted from the two-dimensional laser scanner by comparing the extracted environmental features with a known map of the physical environment;

    the predicted vehicle position update by the Extended Kalman Filter is delayed until a trigger message initiating the vehicle position update is received by the EBN module; and

    the EBN module processes the input messages in the priority queue in the order of acquisition time upon availability of the trigger message.

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