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Automatic steering method and apparatus for a non- railed transfer crane

  • US 5,610,816 A
  • Filed: 04/14/1995
  • Issued: 03/11/1997
  • Est. Priority Date: 09/15/1992
  • Status: Expired due to Term
First Claim
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1. A method for automatically steering a non-railed transfer crane travelling along a lane indicant, comprising the steps of:

  • photographing a lane indicant along the crane'"'"'s travelling direction with a photographing unit having a previously set horizontal center line intersecting with a previously set vertical center line to define a video center point and generating an image signal;

    calculating an actual deviation distance between said video center point and the lane indicant; and

    generating a motor control signal for controlling the rotation of a motor which drives wheels of the crane so that the crane travels toward minimizing said calculated actual deviation distance wherein said generating step further comprises the sub-steps ofcalculating a differential deviation distance δ

    E equal to the difference between said calculated actual deviation distance and a reference deviation distance, andcalculating a voltage signal Vref '"'"' for controlling said motor so that said differential deviation distance can approach zero, wherein said voltage signal Vref '"'"' is calculated with the following equation;

    ##EQU2## wherein Kp represents a proportionality constant having units of voltage per differential deviation distance;

    Kv represents a differential constant having units of voltage per time variation of differential deviation distance;

    Ki represents an integral constant having units of voltage per accumulated values of differential deviation distance; and

    Δ

    T represents a sampling period having units of time.

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