Automatic guided vehicle system

• US 6,208,916 B1
• Filed: 04/20/1999
• Issued: 03/27/2001
• Est. Priority Date: 08/06/1998
• Status: Expired due to Fees

• Current Assignee: Murata Kikai Kabushiki Kaisha (Muratec)
• Original Assignee: Murata Machinery Limited (Muratec)
• Inventors: Hori, Kikuo
• Primary Examiner(s): Zanelli, Michael J.
• Application Number:
  US09/294,141
• Time in Patent Office: 707 Days
• Field of Search: 701/23, 701/25, 701/28, 180/167, 180/168, 180/169, 318/587, 318/568.16
• US Class Current: 701/28
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means

Abstract

A laser scanner recognizes reflectors arranged along a travelling path. A reflector having an angle or a distance falling within an allowable range relative to the last specified reflector is determined to be the same as the previous specified reflector. Based on the locational relationship between such reflectors and those having an angle or a distance outside the allowable range, the reflectors are specified by referencing a reflector map. The reflectors can be specified without assuming the present position of an automatic guided vehicle.

Claims

1. An automatic guided vehicle system comprising

a large number of reflectors arranged along a traveling path;

a laser scanner provided in an automatic guided vehicle to determine the orientation of each reflector by means of periodic scanning;

a reflector map for indicating predetermined positions of the reflectors stored therein;

a means for storing results of a specification of reflectors recognized on a previous scanning;

a means for specifying reflectors recognized during a present scanning by determining a reflector located within a predetermined angle relative to the stored results of the previous scanning to be the same as the last recognized reflector; and

a means for determining the present position of the automatic guided vehicle by comparing the results of the specified reflectors with the predetermined positions of the reflectors stored in the reflector map.

2. An automatic guided vehicle system as in claim 1, wherein said laser scanner determines the orientation of and the distance to the reflector, and in that said specifying means is configured to specify a newly appeared reflector using said reflector map and based on the distance relationship between the newly appeared reflector and the specified reflectors.

3. An automatic guided vehicle system as in claim 1, wherein the velocity and angular velocity of the automatic guided vehicle are determined from at least three specified reflectors, and in that the velocities and angular velocities determined from a previously recognized position until the present time are integrated to determine the present position and orientation.