JPS59184917A - Guiding method of unmanned truck - Google Patents

Abstract

PURPOSE:To guide an unmanned truck by picking up a guiding matter set to the ceiling of a building from the truck by means of an image pickup device and obtaining the plane positional relation between the guiding matter and the truck after catching the image of the guiding matter. CONSTITUTION:A guiding matter 2 is made of a vinyl tape, paper tape, etc. having a different level of luminance from the ceiling surface and stuck to the ceiling of a building along the traveling path of an unmanned truck. The matter 2 is picked up and detected by a guiding matter detecting part 3 set on the truck. Thus the truck travels on a prescribed route. An image pickup device uses a 1-dimensional image sensor 31, and the arraying direction of photodetecting elements of the part 3 is orthogonal to the front-back direction of the truck and at the same time parallel to both floor and ceiling surfaces. An image sensor 31 scans and picks up an angle range of vertical and horizontal directions of the truck, i.e., the direction approximately orthogonal to the lengthwise direction of the matter 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for guiding an automatic guided vehicle in running, stopping, steering, etc.

Progress is being made in the development and practical application of automated guided vehicles that run unmanned on factory floors without relying on rails. The conventional guidance method for automated guided vehicles is to bury electric wires under the floor.
A towpath wire method is known, which uses the electromagnetic waves generated by the current flowing through the wire as information to obtain information, but this method requires a large amount of money for underground construction, is difficult to maintain and inspect, and has disadvantages such as not being easy to change the route. There was also the problem of malfunction due to the reinforcement under the floor.

As a countermeasure, guides made of light emitters or light reflectors are installed on the ceiling of the building along the travel route, and the transport vehicle is equipped with a detector that detects the light from the projector and the guide. A guidance method has been proposed in which a signal emitted when the light from the guide is captured and a signal emitted when the light is no longer captured are made to move in the j/Vf direction in order to follow the guide (4 , v Kosho No. 57-57312)
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However, in this method, since the first general transport vehicle runs only by determining whether it is off the guide, if the width of the guide is narrow, frequent meandering will occur, and if the vehicle is traveling in a 1'ft circle, In order to perform this, it is necessary to increase the width of the guide, but this has the disadvantage that it is difficult to specify the traveling position of the transport vehicle in the width direction of the guide.

The present invention has been made in view of the above circumstances, and its purpose is to arrange a guide strip as a guide on the ceiling of a building along a running route, and which has a different luminance from the background, and to use an imaging device from a transport vehicle. An object of the present invention is to provide a method for guiding an automatic guided vehicle, in which an image of the guide strip is captured by taking an image of the ceiling, and the two-dimensional positional relationship between the guide strip and the guided vehicle is determined while steering the vehicle.

A guiding method for an automatic guided vehicle according to the present invention includes disposing a guide strip having a brightness different from the background on the traveling path of the automatic guided vehicle, and capturing an area including the guide strip using an imaging device mounted on the automatic guided vehicle. It takes an image to detect the image of the guide strip, determines the two-dimensional positional relationship between the guide strip and the automatic guided vehicle, and outputs a steering control signal to maintain this positional relationship in a predetermined reference state. 0 The implementation state of the method of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic front view showing the implementation state of the method of the present invention, and FIG. 2 is a schematic side view, in which 1 indicates an automatic guided vehicle and 2 indicates a guide band. The automatic guided vehicle 1 is equipped with drive wheels 11 and 1r on both sides of the substantially central part in the front and rear directions, and caster-type idle wheels 1f and 1 at the center of each end of the front and rear.
The left and right drive wheels (1 l + 1 r) can be driven independently to enable steering, turning, etc.

The guide strip 2 is made of vinyl tape, paper tape, etc. whose brightness is clearly different from that of the ceiling surface.
is attached to the ceiling of the building along the travel route, and is imaged by the guide strip detection unit '3 mounted on the automatic guided vehicle 1.
Upon detection, the vehicle travels along a predetermined route.

Figure 3 is a schematic diagram of the steering control system.
A dimensional image sensor 31 is used.

The detection unit 3 has its light-receiving element array arrayed in a direction perpendicular to the front-rear direction of the automatic guided vehicle 1 and parallel to the floor and ceiling surfaces,
A one-dimensional image sensor 31 in which the center of the light-receiving element row coincides with the center of the transport vehicle 1 in the left-right direction, and this one-dimensional image sensor 31, The one-dimensional image sensor 31 includes an objective lens 32 and the like for forming a real image of the guide strip 2 on the guide strip 31.
is the range of the angle θ in the upper left and right direction of the transport vehicle 1, that is, the guide band 2
Scanning in a direction almost perpendicular to the length direction of the object. Therefore, when the center of the conveyance vehicle 1 is located directly below the guide strip 2, an image of the guide strip 2 will be formed at the center of the one-dimensional image sensor 31.

The optical signals obtained by the individual light-receiving elements C1 (i is 1-n) of the one-dimensional image sensor 31 are sequentially converted into digital electric signals and given to the binarization circuit 33, which converts them into two types of light and dark at a predetermined darkness value. After being binarized into a signal with a level of -, it is applied to the arithmetic control circuit 4.

The arithmetic control circuit 4 uses a microcomputer, and issues a drive signal to the one-dimensional image sensor 31 to instruct the start of scanning, and converts the resulting digital electrical signals from the individual light-receiving elements Ci into binary values. The servo motor 5 sequentially reads data through the conversion circuit 33 and performs arithmetic processing to be described later, and drives the left and right drive wheels xz and lr based on the results.
A control signal is issued to 1 and 5r.

Hereinafter, the actual steering control will be explained without referring to the flowchart showing the contents of the arithmetic processing of the arithmetic control circuit 4 shown in FIG. For convenience of explanation, it is assumed that the color of the guide strip 2 is relatively bright compared to the color of the ceiling surface, that is, the brightness of the guide strip 2 is relatively low compared to the background. It is assumed that each light receiving element Ci of the image sensor 31 is numbered sequentially from 1 to n from the left side of the carrier 1.

When a drive signal is issued from the arithmetic control circuit 4 to the one-dimensional image sensor 31, the one-dimensional image sensor 31 sequentially outputs a digital signal corresponding to the amount of light received by each light-receiving element Ci to the binarization circuit 33. , the arithmetic control circuit 4 reads the signals from each light receiving element Ci that have been binarized into two levels, bright and dark, from the binarization circuit 33. Incidentally, the binarization threshold of the binarization circuit 33 may be appropriately selected depending on the luminance of the ceiling surface and the guide strip 2; The bright level portion is the image of the guide strip 2.

The numbers of the light receiving elements C8 to C8 in this bright level part are S to I.
C, the arithmetic control circuit 4 has a central light receiving element CM.
Find the number M using the following formula +1).

However, M: number of the light receiving element CM at the center of the image of the guide strip S, E: number of the light receiving element C8° C8 at both ends of the image of the guide strip, then the guide strip 2 imaged on the one-dimensional image sensor 31
The deviation of the center of the image from the center of the light-receiving element row of the one-dimensional image sensor 31 is determined. That is, the number N of light receiving elements between the light receiving element Cn/2 at the center of the one-dimensional image sensor 31 and the light receiving element CM at the center of the image of the guide strip 2 is calculated using the following equation (2).

N=Mn/2...(2) However, N
: Number of light-receiving elements from the center of the light-receiving element row to the center of the guide line image n/2: Number of light-receiving elements at the center of the light-receiving element row When the number N of light receiving elements between the center of the column is calculated,
The arithmetic control circuit 4 performs the left and right operations necessary to make the value of N zero.
Right drive wheel II! .

The steering amount for 1r is determined, and the control signal necessary to achieve this is sent to each drive wheel 1j? , servo motor 5/ for lr,
Output to 5r. For example, when the automatic guided vehicle 1 is driven with its body center positioned directly below the guide strip 2, the number of light receiving elements N is positive or negative ((the guided vehicle is displaced to the right from the widthwise center of the guide strip 2) If it is positive, the left and right drive wheels 1 l are determined.

Of 1r, the rotation speed of the left drive wheel 1r is also the right drive wheel 11! If the number of rotations is high and negative, the right drive wheel 1
A control signal is output so that the rotation speed of the left drive wheel 1r becomes higher than the rotation speed of the left drive wheel 1r. The value of the relative rotational speed difference is not particularly limited, and may be determined as appropriate so that the transport vehicle 1 can run smoothly.

Note that the conveyance vehicle 1 does not necessarily need to be driven with its body center located directly below the guide strip 2; for example, as shown in FIG.
Of course, it is also possible to run the vehicle with the position shifted by 1. In this case, instead of the light receiving element Cn/2 at the center of the one-dimensional image sensor 31, the light receiving element Ci of an appropriate number is used as the reference. , the number N' of light receiving elements between the guide strip 2 and the light receiving element CM at the center of the image may be calculated, and the same processing may be performed thereafter. In this way, one guide strip 2
It is also possible to run a plurality of conveyance vehicles 1 in parallel by using this.

In the method of the present invention as described above, since the guide strip 2 is constructed using a guide strip 2 whose brightness is different from that of the background, adhesive is applied to the back side of vinyl tape, paper tape, etc., and the beam of the building is Since it can be easily attached to the bottom surface etc., the guide strip 2 can be installed and removed extremely easily, and even when changing the travel route of the guided vehicle 1, the guide strip 2 can be easily attached by changing the adhesive. This can be done easily.

Furthermore, it is also possible to draw the guide strip 2 directly on the ceiling surface using paint or the like. In addition, since the guide f2 is provided on the ceiling surface, there is no problem such as accumulation of dust on the guide strip 2 even in a building with a lot of dust, and maintenance of the surface of the guide strip 2 is easy. Even if the surface is partially dirty, since the guide strip 2 is formed into a long strip, scanning by the one-dimensional image sensor 31 from the transport vehicle 1 will immediately remove the surface from the clean guide strip 2 again. Since the image of the transport vehicle 1 cannot be obtained, inconveniences such as the transport vehicle 1 losing sight of the traveling route do not occur.

The guide strip 2 may be arranged continuously above the entire length of the traveling path, but it may be divided into appropriate lengths and arranged at regular intervals within a range that does not interfere with the traveling of the guided vehicle 1. It's okay. It goes without saying that a television camera or the like may be used as the imaging device.

As described in detail below, the nine methods for attracting automatic guided vehicles according to the present invention include placing a guide strip of a color clearly different in brightness from the background above the route of the automatic guided vehicle; Each time an image is captured and detected by an imaging device mounted on a guided vehicle, the planar positional relationship of the automated guided vehicle with respect to the guide strip is determined, and based on this, the steering control of the automated guided vehicle is performed. It does not impede the walking of people or the running of other transport vehicles, there is little risk of damage or staining the guide strip, and it is also possible to attach strips of paper or other material with adhesive. Because of this, it is easy to change the travel route, guide the transport vehicle, and
(It is also possible to run multiple conveyance vehicles in parallel with one guide strip, and use inexpensive paper tape as the guide strip.) The present invention has excellent effects such as being able to be used.

[Brief explanation of the drawing]

Fig. 1 is a schematic front view showing the implementation state of the method of the present invention, Fig. 2 is a schematic side view as well, Fig. 3 is a schematic diagram showing the steering control system, and Fig. 4 shows the steering control mode. The explanatory diagram, FIG. 5, is a flowchart showing the content of arithmetic processing by the arithmetic control circuit. 1...Automated guided vehicle 1f, lr...Drive wheel if,
lb... Idle wheel 2... Guide band 3... Guide band detection section 4... Arithmetic control circuit 31... Imaging device patent applicant Tsubakimoto Chain Co., Ltd., agent patent attorney
Noboru Kono Figure 1 ? Figure 3 Figure 1A4 Figure 5

Claims (1)

[Claims] 1. Arranging a guide strip with brightness different from the background above the travel path of the automatic guided vehicle, and detecting an image of the guide strip by capturing an image of an area including the guide strip with an imaging device mounted on the automatic guided vehicle; A method for guiding an automatic guided vehicle, comprising determining a two-dimensional positional relationship between the guide strip and the automatic guided vehicle, and outputting a steering control signal to maintain this positional relationship in a predetermined reference state. .