Claims
- 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 of
- calculating a differential deviation distance .delta..sub.E equal to the difference between said calculated actual deviation distance and a reference deviation distance, and
- calculating a voltage signal V.sub.ref ' for controlling said motor so that said differential deviation distance can approach zero, wherein said voltage signal V.sub.ref ' is calculated with the following equation: ##EQU2## wherein K.sub.p represents a proportionality constant having units of voltage per differential deviation distance;
- K.sub.v represents a differential constant having units of voltage per time variation of differential deviation distance;
- K.sub.i represents an integral constant having units of voltage per accumulated values of differential deviation distance; and
- .DELTA.T represents a sampling period having units of time.
- 2. An automatic steering apparatus for controlling a non-railed transfer crane travelling along a lane indicant defining a lane, comprising:
- a camera having a photographing unit for continuously photographing an off-centered condition between the direction of travel of said crane and said lane during the travel of said crane, said photographing unit having a previously set horizontal line intersecting with a previously set vertical line to define a video center point at said intersection;
- means for converting a video signal input from said camera into a digital image signal;
- means for calculating an actual deviation distance between said video center point and said lane indicant from said image signal;
- a deviation processor for receiving the calculated actual deviation distance from said calculating means, said deviation processor calculating a differential deviation distance .delta..sub.E equal to the difference between said calculated actual deviation distance and a reference deviation distance, calculating a voltage signal V.sub.ref ' so that said differential deviation distance can approach zero, and generating a control signal based upon said calculated voltage signal to control a motor which drives wheels of said crane to travel toward minimizing the actual deviation distance; and
- a motor driver for controlling said motor according to the control signal supplied from said deviation processor, wherein said voltage signal V.sub.ref ' is calculated with the following equation: ##EQU3## wherein K.sub.p represents a proportionality constant having units of voltage per differential deviation distance;
- K.sub.v represents a differential constant having units of voltage per time variation of differential deviation distance;
- K.sub.i represents an integral constant having units of voltage per accumulated values of differential deviation distance; and
- .DELTA.T represents a sampling period having units of time.
- 3. The automatic steering apparatus of claim 2, wherein said means for calculating said actual deviation distance further comprises:
- an interfacing unit for converting said video signal supplied from said camera into said image signal;
- a memory for storing the image signal input from said interfacing unit; and means for calculating actual deviation distance between the crane's travelling direction and the lane based on image data input from said memory and stored data representing a normal condition of steering.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9216761 |
Sep 1992 |
KRX |
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CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of application Ser. No. 08/119,465 filed on Sep. 10, 1993 now abandoned.
US Referenced Citations (17)
Foreign Referenced Citations (1)
Number |
Date |
Country |
WO9219526 |
Nov 1992 |
WOX |
Continuations (1)
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Number |
Date |
Country |
Parent |
119465 |
Sep 1993 |
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