JPS61250709A - Method for discriminating mark of unattended track - Google Patents

Abstract

PURPOSE:To obtain a mark discriminating method for an unattended tack where the mark is discriminated with high accuracy by installing plural magnets to the mark part in different pattern. CONSTITUTION:Mark detectors 7a, 7b are arranged in order in the progressing direction of the unattended track 1, the same sensitivity is given to them and they generate an output proportional to a distance between a mark guide line 6 and the 1st and 2nd lead sections 6a, 6b when the line 6 approaches the sections 6a, 6b and is parted from them. The distance (l) between the lead sections 6a, 6b of the mark guide line 6 is selected differently depending on the kind of mark, and the unattended track 1 measures the running distance that after the difference of the outputs of the mark detectors 7a, 7b is zero at the passing of the 1st lead section 6a, the difference is again zero by the passing of the 2nd lead section 6b attended with the running of the track 1 by counting the pulse number generated from a pulse encoder 4, and discriminates the kind of the mark 6 depending on that the running distance corresponds to the distance (l) of the 1st and 2nd lead sections 6a, 6b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for identifying marks on an automatic guided vehicle that travels along a guideway laid on a floor surface.

[Conventional Technology J This type of automated guided vehicle is generally used to transport cargo in factories, etc., and in order to improve operational efficiency, branching points and merging points are provided on the taxiway, and various work points are installed. If appropriate, different types of marks indicating the position must be provided for each of these points, and these marks must be automatically read and identified by the automatic guided vehicle to control travel. Conventionally, as a method for identifying marks by such an automatic guided vehicle, a plurality of magnetic proximity switches are used, in which an automatic guided vehicle is provided with a mark consisting of a plurality of magnets installed in different patterns at each point on the taxiway. Either by reading and identifying the mark, or by supplying an induced current with a different frequency for each type of mark, the automatic guided vehicle reads this induced current and determines the type of mark based on the frequency.

[Problems to be Solved by the Invention] However, with this conventional method, the reading of the magnet pattern by the magnetic proximity switch is greatly affected by the attitude of the automatic guided vehicle, making it unstable to distinguish between marks. It lacks reliability, and the latter requires multiple types of induced current to be supplied to each mark separately from the guideway, which requires complicated and time-consuming cutting work for each mark and installation of the guide wire. Both had problems, such as restrictions on where they could be installed.

This invention solves the problems of the conventional methods as described above, and it is possible to install a plurality of magnets in different patterns on the mark part, and to install an induction wire to which induction currents of different frequencies are supplied. Unmanned transportation that does not require complicated and time-consuming work such as installation, allows marks to be installed with simple work, and has high reliability in detecting and distinguishing marks, allowing for highly accurate mark discrimination. The purpose of this invention is to provide a method for identifying car marks.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides an automated guided vehicle that runs along a taxiway laid on the floor with a first motor vehicle that is pulled out laterally from the taxiway. Two detectors for detecting a mark having a drawer part and a second drawer part are provided one after the other in the traveling direction, and each of the detectors passes through the first and second drawer parts as the automatic guided vehicle travels. generates an output when
The type of the mark is determined based on the travel distance until the difference in the outputs of the two detectors becomes zero after passing through the first drawer and becomes zero again after passing through the second drawer.

[Function] By employing the above means, the present invention allows marks to be placed with simple work, and for example, by using only one detector, the output of this detector can be set at a predetermined reference level. If the mark is detected by exceeding the voltage, it is essential to have a means to generate a reference voltage that is the reference level, and the accuracy of the mark detection position is unstable, so it is difficult to stop after detecting the mark. If high accuracy is required for positioning, an auxiliary means for position correction such as a centering cone must be used, but this invention uses two detectors so that the difference between the outputs of both detectors becomes zero. Since the positions of the first and second lead-out portions of the mark are detected respectively, there is no need for reference voltage generation means or auxiliary means for position correction, and the positional accuracy of mark detection is high. This means that it is possible to determine the

[Example] Embodiments of the invention shown in the drawings will be described below.

FIG. 1 shows an embodiment of the present invention, in which reference numeral 1 denotes an automatic guided vehicle that travels along a main guide line 2 laid on the floor to form a guideway. 3, a pulse encoder 4 that generates pulses according to the rotation of the drive wheel 3, and a magnetic field generated in the main guide wire 2.
Travel detectors 5a and 5b consisting of pickup coils that detect on the left and right of the vehicle and guide the travel direction, and the main guide wire 2.
The first pull-out part 6a and the second pull-out part 6a are pulled out laterally at right angles from the
Mark detectors 7a and 7b are provided which have a lead-out portion 6b and are comprised of pickup coils that detect the magnetic field generated in the mark-induced S wire 6 formed in a U-shaped loop. The mark detectors 7a and 7b are arranged one after the other in the traveling direction of the automatic guided vehicle 1, and are set to have the same sensitivity to each other, so that the mark detectors 7a and 7b are set to have the same sensitivity when approaching the first and second lead-out portions 6a and 6b of the mark guide line 6 and thereafter. When moving away, the first and second drawer portions 6a
, 6b, respectively.

Distance between the first and second lead-out portions 6a and 6b of the mark guide line 6! are set to different lengths depending on the type of mark, and as the automatic guided vehicle 1 travels, the mark detector 7
By counting the number of pulses generated from the pulse encoder 4, the distance traveled until the difference between the outputs of outputs a and 7b becomes zero after passing through the first drawer part 68 and becomes zero again by passing through the second drawer part 6b is calculated. The type of mark 6 is determined based on the distance traveled corresponding to the distance l between the first and second drawer portions 6a and 6b.

When the automatic guided vehicle 1 described above travels along the main guide line 2 and approaches the mark guide line 6, as shown in FIG.
First, the mark detector 7a at the front in the traveling direction is located at the first drawer section 6a.
The mark detector 7b at the rear in the traveling direction detects the first drawer part 6a and generates a chevron-shaped output 8a which has a maximum value right above the first drawer part 6a. A chevron-shaped output 8b having a maximum value is generated at a position directly above the first drawer portion 6a. The output waveform 8a of the mark detector 7a and the output waveform 8b of the mark detector 1b are the same waveforms with only the phase shifted because both detectors 7a and 7b are set to the same sensitivity. 1b is the first drawer part 6a
The two waveforms 8a and 8b that are equidistant from each other intersect, and this intersection point C is determined by subtracting the output 8b of the mark detector 1b from the output 8a of the mark detector 7a, as shown in FIG. is converted to the zero crossing point C6 and therefore both detectors 7a, 7b as shown in FIG.
When the difference between the outputs of both detectors 7a becomes zero, that is, both detectors 7a.

It is detected that the first drawer portion 6a is located in the center between the two portions 7b. Subsequently, the mark detectors 7a and 7b sequentially detected the second drawer portion 6b and generated outputs 8c and 8d, and as shown in FIG. 3, the difference between the outputs 8C and 8d became zero. At the zero crossing point C1, that is, both detectors 7a,
It is detected that the second drawer portion 6b is located at the center of the second drawer portion 7b. By counting the number of pulses generated from the pulse encoder 4 between the zero-cross point C8 at which the mark detectors 7a and 1b detect the first pull-out portion 6a and the zero-cross point C1 at which the second pull-out portion 6b is detected, The 1st and 2nd drawer portions 6a and 6 correspond to the distance traveled during that time.
The spacing l of b can be measured, thereby marking 6
This means that the type can be determined.

In the above embodiment, the first and second lead-out portions 6a and 6b were drawn out at right angles from the main guide line 2, but the present invention is not limited to this, and the mark guide line 6 was formed into a mouth-shaped loop. It goes without saying that the present invention is not limited to the above embodiments, and that various changes and modifications to the above-described embodiments can be made.

[Effect of the invention]
4゜Since the present invention is configured as described above, it is not complicated to install multiple magnets in different patterns in the mark portion, or to install induction wires to which induced currents of different frequencies are respectively installed. Marks can be placed easily without the need for labor-intensive work; for example, when only one detector is used and the output of this detector exceeds a predetermined reference level, the mark can be placed. When detecting a mark, it is essential to have a means to generate a reference voltage that is a reference level, and the mark detection position accuracy is unstable, so a high degree of accuracy is required for the stop position after mark detection. However, when the mark is detected, it is necessary to use an auxiliary means for position correction such as a centering cone, but such a reference voltage generation means and auxiliary means for position correction are not required, and the positional accuracy of mark detection is high. It has excellent effects such as high reliability in detection and discrimination and the ability to discriminate marks with high accuracy.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, FIG. 2 is an output waveform diagram of the mark detector of the one shown in FIG. 1, and FIG.
FIG. 3 is a waveform chart showing the difference between the output waveforms in the figure. 1...Automated guided vehicle, 2...Main guide line, 3...
Drive wheel, 4...Pulse encoder, 5a, 5b...
・Travel detector, 6... mark guide line, 6a... first
Drawer part, 6b...Second drawer part, 7a, 7b/V-reflector, 8a18b, 8c, 8d--Output (waveform), C...Intersection, Co1C1...Zero cross point. Applicant: Sanki Kogyo Co., Ltd.

Claims (1)

[Scope of Claims] 1. A mark having a first pull-out part and a second pull-out part pulled out laterally from the guideway is detected on an automated guided vehicle traveling along a guideway laid on the floor. Two detectors are provided one after the other in the traveling direction, and each of the detectors generates an output when the automatic guided vehicle passes through the first and second drawer sections as the automatic guided vehicle travels, and the outputs of both the detectors are A mark for an automatic guided vehicle, characterized in that the type of the mark is determined based on the travel distance until the difference becomes zero after passing through the first drawer and becomes zero again after passing through the second drawer. Discrimination method. 2. The mark discrimination method for an automatic guided vehicle according to claim 1, wherein the first drawer part and the second drawer part are drawn out at right angles to the guideway. 3. The mark discrimination method for an automatic guided vehicle according to claim 1, wherein the mark is formed in a loop shape. 4. The mark discrimination method for an automatic guided vehicle according to claim 1, wherein each of the detectors generates an output proportional to the distance between the first and second drawer parts.