Running control method and apparatus of the automatic guided vehicles

• US 4,908,557 A
• Filed: 10/17/1988
• Issued: 03/13/1990
• Est. Priority Date: 03/31/1988
• Status: Expired due to Term

• Current Assignee: Tsubakimoto Chain Company
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Sudare, Masahiro, Minami, Mamoru, Tomikawa, Hisao
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US07/258,548
• Time in Patent Office: 512 Days
• Field of Search: 318/587, 318/139, 318/568, 180/167, 180/168, 180/169, 446/175, 446/444, 446/445, 364/424.01, 364/424.02, 364/424.04, 364/513, 358/103, 358/108, 901/1, 901/50, 901/46, 901/47
• US Class Current: 318/587
• CPC Class Codes: G05D 1/0261 using magnetic plots

Abstract

This invention relates to a running control apparatus and method for calculating the running positions and directions of the automatic guided vehicle in response to detected outputs of the magnetic field intensity of magnets arranged at fixed points on the running course in two-dimension by being detected for several times at a predetermined timing by a plurality of magnetic detecting elements which are aligned in a direction intersecting the moving direction of the vehicle, correcting said running positions and directions, and controlling the automatic guided vehicle.

Claims

1. A running control method of an automatic guided vehicle which runs as detecting the running position and direction, characterized by detecting the magnetic field intensity of magnets arranged at fixed points on running courses, said detecting being conducted several times at a predetermined timing with a plurality of magnetic detecting elements aligned in a direction intersecting the moving direction of the vehicle, to calculate at least a first running position and direction of the automatic guided vehicle in response to detected outputs over a plurality of times of conducting said detecting of each of said plurality of magnetic detecting elements, wherein at least said calculated running position includes a position calculated in a first dimension substantially along said moving direction and a second dimension substantially along said direction intersecting the moving direction, and to correct said running positions and directions so as to follow said running courses according to the calculated values.

3. A running control method as claimed in claim 1, wherein said calculation of the running position and direction comprises the steps of:

ternarizing each magnetic detecting element output among high, medium, and low level at every said timing;

scanning ternarized outputs in the aligned direction by using a window having a predetermined length in said direction;

determining a region pair which comprises two regions of the ternarized output of equal level on the basis of ternarized output at both ends of said window;

obtaining a shortest distance with respect to said two regions; and

obtaining a center position of said two regions on the basis of said shortest distance.

4. A running control method, as claimed in claim 1, wherein said correction of said running positions comprises:

obtaining a first running position of a first fixed point with respect to said automatic guided vehicle in said first dimension and said second dimension;

obtaining a second running position of a second fixed point with respect to said automatic guided vehicle in said first dimension and said second dimension;

using said first and second running positions to obtain a running direction;

comparing said running direction to a predefined course; and

correcting the running direction of said automatic guided vehicle based on said comparison of said running direction to said course.

5. A running control method, as claimed in claim 1, further comprising:

obtaining a second running position in real time on the basis of automatic guided vehicle wheel rotation;

comparing said first running position with said second running position; and

eliminating accumulated errors by replacing said second running position with said first running position.

2. A running control apparatus of an automatic guided vehicle which runs as detecting the running position and direction, comprising:

a plurality of magnetic detecting elements aligned in a direction intersecting the moving direction of the vehicle for detecting the magnetic field intensity of magnets arranged respectively at fixed points on running courses;

a detecting control portion which controls to detect said magnetic detecting elements for several times adjacent said magnets at a predetermined timing;

a position calculating portion which converts the detected magnetic field intensity over a plurality of times of detecting by said plurality of magnetic detecting elements into a distribution pattern of moving direction of the vehicle and its intersecting direction, to calculate the running position and direction of said automatic guided vehicle in response to converted data, wherein at least said calculated running position includes a position calculated in a first dimension substantially along said moving direction and a second dimension substantially along said direction intersecting the moving direction; and

an operation control portion which corrects said running position and direction so as to follow along said running courses.