JP2001042935A - Automated guided vehicle travel system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the position detection precision nearby the center position of respective antenna coils by arraying the antenna coils in the width direction of an automated guided vehicle so that both ends of the antenna coils overlap with each other. SOLUTION: An board antenna unit 40 has antenna coils 41 to 45 arranged in the shape shown in Fig. (a). Namely, the antenna coils 41 to 45 of respective channels are so expanded laterally as to overlap with the adjacent antenna coils 41 to 45. The graph (b) shows the relationship between the lateral positions of a data carrier about the onboard antenna unit 40 and the output levels of the respective channels when the data carrier is moved in parallel at arbitrary upper or lower height. Adjacent channels do not decrease greatly in electric field intensity level nearby the center position of the respective channels, so the position detection precision nearby the center of the respective channels is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a device called an interrogator attached to a moving object and a card or an electronic tag called a transponder which is fixed and stores various information. The present invention relates to a system for reading and writing information in a non-contact manner by radio waves or electromagnetic coupling, that is, an RF-ID technology and a data carrier technology, and particularly to an unmanned carrier traveling system in which the interrogator is attached to an unmanned carrier. is there.

[0002]

2. Description of the Related Art RF-ID using cards, electronic tags, etc.
Technology is transponder in the fields of FA, logistics, security, etc.
Various systems combining interrogators have been put into practical use (literature: "Data Carrier Technology and Application", published by Nikkan Kogyo Shimbun; pages 125 to 127). A conventional technique relating to an unmanned transport system in the physical distribution field described in the above-mentioned document will be described. FIG. 3 shows a conventional automatic guided vehicle system. In the figure, 10 is an automatic guided vehicle (hereinafter referred to as a guided vehicle), 11 is a traveling electromagnetic induction wire for guiding the guided vehicle, and 12 is mounted on the guided vehicle and includes an antenna, an on-vehicle receiver, and the like. The interrogator 13 is a transponder called a data carrier (electronic tag or the like) on which various information is recorded, and is installed on the ground surface.

[0003] A running mode of this system will be described. The carrier 10 that has been guided by the traveling electromagnetic induction wire 11 is:
When passing through the data carrier 13, communication with the interrogator 12 mounted on the carrier (data carrier information reading) is performed. In the illustrated system, for example, information is received from the data carrier immediately below the vehicle as to whether the vehicle is going straight ahead, turning left, or turning right at an intersection in front. The purpose of the data carrier in this system is only to provide information to the carrier, that is, to provide information on the stop and traveling direction of the carrier, and so the data carrier is installed only at a specific location on the traveling path.

However, recently, for the purpose of moving a carrier to an arbitrary point on a road through an arbitrary route, a fixed traveling electromagnetic induction wire is removed, and the number of data carriers is increased instead. A new system (hereinafter, referred to as a new system) has been developed that provides travel guidance at the same time as providing information to a carrier. In this new system, it is required that the data carrier be simple and inexpensive to install, and that the information data be rewritten without contact. That is, this new system is a type of automatic traveling (automatic driving) technology for automatic guided vehicles.

[0005] Although a detailed description of this new system is omitted, in short, a plurality of data carriers are installed at intervals within the entire length of the carrier on the traveling path of the carrier. When the vehicle passes, the interrogator corresponding to the full width of the vehicle (hereinafter referred to as the vehicle-mounted antenna) installed in the lower part in front of the vehicle is used to exchange information with the data carrier. Position information indicating the positional relationship with the vehicle is detected on the carrier side, and automatic driving control is performed by a prediction process such that the next data carrier always passes through the center of the on-vehicle antenna during traveling.

The exchange of information and detection of position information in this new system will be described with reference to FIG. In FIG. 4A, reference numeral 20 denotes a unit of an on-vehicle antenna mounted on a carrier, and 21 to 25 denote a plurality of small and same-shaped multiple antenna coils incorporated in the unit of the on-vehicle antenna (in the example of FIG. 5ch antenna coil is disposed), and the antenna coil of each channel is provided with an independent 5-channel detection circuit of a receiver (not shown), that is, five information detection circuits for detecting information from a data carrier, Detecting a radio wave or electromagnetic field intensity level (hereinafter, referred to as electric field intensity) from the data carrier 5
Connected to the electric field strength detection circuits. Although the shape of the antenna coil in the figure is rectangular, it is functionally the same when it is circular or elliptical.

Information exchange with a data carrier is detected on any one of five channels. The electric field strength is output in a form in which the output level of each channel changes according to the positional relationship between the data carrier and the antenna coil of each channel. The center position of the in-vehicle antenna is calculated for the data carrier from the difference in the electric field strength levels of the five channels to detect the position information.

The method of calculating the position information is as follows. The position of the data carrier is adjusted in advance in the direction indicated by the arrow 26 in FIG. When moving, the relationship between the lateral position of the data carrier with respect to the in-vehicle antenna and the output level of each channel is detected, and this is stored in the memory of the receiver as reference data for position information detection.

FIG. 4B shows a 5-channel configuration.
This is a graph of the reference data for position information detection from the electric field strength level of each channel obtained experimentally, the vertical axis shows the electric field strength level of each channel, and the horizontal axis shows the data carrier and the in-vehicle antenna. In the horizontal direction.

The position information of the traveling carrier is detected by comparing and comparing the output levels of the five channels when passing through the data carrier with the reference information for position information detection stored in the memory of the receiver.

[0011]

However, the conventional technique has the following problems as can be understood from the graph of the reference data for detecting position information in the case of five channels shown in FIG. There is. (1) In the vicinity of the center position of each channel, the electric field strength level of the adjacent left and right channels is extremely low, so that the position detection accuracy is reduced. However, in the vicinity of the right and left boundary points (lateral end surfaces of the antenna coil), the position detection accuracy is small. Improves. As described above, the position detection accuracy changes depending on the lateral position of the antenna. (2) In the vicinity of the left and right boundary points in each channel,
Since the mutual electric field strength levels are experimentally reduced by about 50%, it is difficult to detect information from the data carrier, and the information reading rate is reduced.

Naturally, it is considered that the position detection accuracy of the whole system can be solved by increasing the number of channels mounted on the unit of the vehicle-mounted antenna, but the cost of the whole system increases due to the increase of the number of channels of the antenna coil and the receiver. There is a problem of doing.

An object of the present invention is to provide an automatic guided vehicle traveling system capable of solving the above-mentioned conventional problems without increasing the number of channels mounted on a unit of an on-vehicle antenna.

[0014]

For this purpose, in an automatic guided vehicle traveling system according to the present invention, an antenna unit including a plurality of antenna coils and a plurality of information detection circuits and a position detection circuit corresponding to each antenna coil are provided. An interrogator consisting of a built-in receiver is mounted on an automatic guided vehicle, and information is exchanged and position information is detected between a data carrier installed on the ground surface as a responder and the interrogator to automatically operate the automatic guided vehicle. In the automatic guided vehicle traveling system for traveling, the plurality of antenna coils are arranged in a line in a width direction of the automatic guided vehicle, and both ends of each antenna coil are overlapped.

The automatic guided vehicle traveling system according to the present invention comprises an antenna unit including a plurality of antenna coils, a plurality of information detection circuits corresponding to each antenna coil, and a receiver having a built-in position detection circuit. An automatic guided vehicle traveling system in which an interrogator is mounted on the automatic guided vehicle and the automatic guided vehicle travels by performing information transfer and position information detection between a data carrier installed on the ground surface as a responder and the interrogator and automatically detecting the automatic guided vehicle. In the above, the plurality of antenna coils are arranged in a row in the width direction of the automatic guided vehicle, and the length of each antenna coil in the width direction is set such that the coil at the center becomes the minimum width, and the coils are moved toward both ends. The antenna coil shape is such that the width becomes long.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 (a) shows a unit configuration (arrangement of five channels) of a vehicle-mounted antenna according to a first embodiment. In the figure, 4
Numeral 0 denotes an on-vehicle antenna unit mounted on the carrier, and numerals 41 to 45 denote shapes and arrangements of the antenna coils arranged in the unit.

The on-vehicle antenna unit 40 is mounted on a lower front portion of a carrier (not shown). Each of the antenna coils 41 to 45 is connected to an independent data carrier information detection circuit of a receiver (not shown) and an electric field intensity detection circuit for detecting the electric field intensity from the data carrier.

In this configuration, when the data carrier is translated in advance at an arbitrary height of up or down with respect to the 5-channel vehicle-mounted antenna, the lateral position of the data carrier with respect to the vehicle-mounted antenna and the output level of each channel are determined. And this data is stored in the memory of the receiver as position information detection reference data.

The information transfer between the traveling carrier and the data carrier is detected on any one of the five channels when passing through the data carrier, and at the same time, the position information detection processing is performed on the five-channel electric field strength detection circuit. And the reference level for position information detection already stored in the memory of the receiver.

According to the shapes and arrangements of the antenna coils 41 to 45 shown in FIG. 1A, the shapes of the antenna coils of each channel are enlarged in the horizontal direction, and the adjacent antenna coils are arranged so as to partially overlap each other. are doing. FIG. 1 (b)
The horizontal position of the data carrier with respect to the vehicle-mounted antenna and the output level of each channel when the data carrier is translated at an arbitrary height up or down with respect to the antenna coil having such a shape and arrangement. The relationship, that is, a graph of the reference data for position information detection, the vertical axis indicates the electric field intensity output level of each channel,
The horizontal axis indicates the horizontal position of the data carrier and the vehicle-mounted antenna.

As can be seen from the graph of FIG. 1B, in the present embodiment, the electric field strength levels of the adjacent left and right channels do not significantly decrease near the center position of each channel. The position detection accuracy near the center position is improved, and the conventional problems are solved. As a result, the position detection accuracy is averaged over the entire on-vehicle antenna unit, and the decrease in the information reading rate is improved because the electric field intensity level near the boundary between the channels is increased.

(Second Embodiment) FIG. 2A shows the unit configuration (arrangement of 5 channels) of a vehicle-mounted antenna according to a second embodiment. In the figure, reference numeral 60 denotes a vehicle antenna unit, and reference numerals 61 to 65 denote shapes and arrangements of antenna coils arranged in the unit.

An on-vehicle antenna unit 60 is mounted on the front lower part of a carrier (not shown). The antenna coils 61 to 65 are provided with an information detecting circuit for a data carrier of five independent channels of a receiver (not shown) for each channel. , Is connected to an electric field intensity detection circuit for detecting the electric field intensity from the data carrier.

As described in the first embodiment, also in this embodiment, the relationship between the lateral position of the data carrier with respect to the vehicle-mounted antenna and the output level of each channel is detected, and this is used as reference data for position information detection. It is stored in the memory of the receiver.

The information transfer between the traveling carrier and the data carrier is detected on any one of the five channels when passing through the data carrier, and at the same time, the position information is output from the independent five-channel electric field strength detection circuit. The position information is detected by comparing and comparing the position information with reference data for position information detection stored in the memory of the receiver.

The feature of this embodiment lies in the shape of a 5-channel antenna coil constituting a unit of a vehicle-mounted antenna. As is clear from the antenna coils 61 to 65 shown in FIG. 2A, in the present embodiment, the lateral shape of the antenna coil is such that the shape of the center channel (3ch) is the smallest, and that of the left and right channels (2ch). , 4ch) have the same shape as the coils of channels 1 to 5 in the first embodiment, and the outer channels (1ch, 5ch) have the longest shape. FIG. 2B shows the lateral position of the data carrier with respect to the vehicle-mounted antenna and each channel when the data carrier is translated at an arbitrary height of up or down with respect to the antenna coil having such a shape and arrangement. Is a graph of the reference data for position information detection, the vertical axis indicates the electric field strength output level of each channel, the horizontal axis indicates the horizontal position of the data carrier and the vehicle-mounted antenna. ing.

In this embodiment, as described in the section of the problem to be solved by the invention, the position detection accuracy of the whole vehicle-mounted antenna changes depending on the lateral position of the vehicle-mounted antenna, An object of the present invention is to solve the problem that the position detection accuracy at the center position of the more important in-vehicle antenna is lowered among the problems that the position detection accuracy at the center position is reduced.

Originally, while the carrier is traveling, automatic operation control is performed so that the next data carrier always passes through the center of the on-vehicle antenna. Even if the position detection accuracy decreases as the distance to the ends of the antenna decreases, there is almost no problem in traveling.

As can be seen from the graph of FIG. 2B, in this embodiment, by changing the shape of the antenna coil of each channel, adjacent channels (2ch, 4ch) near the center position (3ch) of the vehicle-mounted antenna. The position detection accuracy is increased by increasing the electric field intensity level of (2), and as a result, the position detection accuracy decreases as the position approaches both ends of the vehicle-mounted antenna. As a result, the position detection accuracy of the center position of the antenna is improved, and the effect of the meandering operation of the carrier traveling in the center of the normal data carrier is reduced.

[0030]

As described above in detail, according to the first aspect, a receiving unit having a built-in antenna unit including a plurality of antenna coils and a plurality of information detecting circuits and position detecting circuits corresponding to the respective antenna coils is provided. An unmanned vehicle that mounts an interrogator consisting of a device on an unmanned carrier, performs information transfer and position information detection between a data carrier installed on the ground surface as a responder and the interrogator, and automatically drives the unmanned carrier. In the transport vehicle traveling system, the plurality of antenna coils are arranged in a row in the width direction of the automatic guided vehicle, and the both ends of each antenna coil are overlapped. Since the electric field intensity levels from the adjacent left and right antenna coils do not greatly decrease, the position near the center position of each antenna coil Out accuracy is improved. In addition, the position detection accuracy is averaged over the entire vehicle antenna unit,
Further, since the electric field strength level near the boundary point between the antenna coils is increased, the decrease in the information reading rate is also improved.

According to the second aspect of the present invention, an interrogator including an antenna unit including a plurality of antenna coils, a plurality of information detection circuits corresponding to the respective antenna coils, and a receiver having a built-in position detection circuit is provided. An unmanned guided vehicle traveling system mounted on a guided vehicle and automatically traveling the unmanned guided vehicle by performing information transfer and position information detection between the data carrier installed on the ground surface as a transponder and the interrogator, The antenna coils are arranged in a line in the width direction of the automatic guided vehicle, and the length in the width direction of each antenna coil is set so that the coil at the center becomes the minimum width, and the width of the coil becomes longer toward both ends. With the antenna coil shape as described above, the electric field strength level from the adjacent antenna coil increases in the antenna coil at the center of the vehicle-mounted antenna unit. The position detection accuracy is enhanced by Rukoto improves the accuracy of position detection at the central position of the antenna unit, there is an effect that the degree of meandering operation of the transport vehicle traveling a normal data carrier center is reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a vehicle-mounted antenna and a graph of position information detection reference data according to a first embodiment.

FIG. 2 is a diagram showing a configuration of a vehicle-mounted antenna and a graph of position information detection reference data in a second embodiment.

FIG. 3 is an explanatory diagram of a conventional automatic guided vehicle system.

FIG. 4 is a diagram showing a configuration of a conventional in-vehicle antenna and a graph of reference data for detecting position information.

[Explanation of symbols]

40 Antenna units 41 to 45 in the first embodiment Each antenna coil in the first embodiment 60 Antenna units 61 to 65 in the second embodiment Each antenna coil in the second embodiment

Claims (2)

[Claims] An interrogator including an antenna unit including a plurality of antenna coils, a plurality of information detection circuits corresponding to the respective antenna coils, and a receiver having a built-in position detection circuit is mounted on an automatic guided vehicle. In an automatic guided vehicle traveling system for automatically traveling the automatic guided vehicle by transmitting and receiving information and detecting position information between a data carrier installed on the ground surface and the interrogator, the plurality of antenna coils are connected to the automatic guided vehicle. An automatic guided vehicle traveling system, wherein the antenna coils are arranged in a row in the width direction and both ends of each antenna coil are overlapped. 2. An unmanned carrier equipped with an interrogator including an antenna unit including a plurality of antenna coils, a plurality of information detection circuits corresponding to the respective antenna coils, and a receiver having a built-in position detection circuit. In an automatic guided vehicle traveling system for automatically traveling the automatic guided vehicle by transmitting and receiving information and detecting position information between a data carrier installed on the ground surface and the interrogator, the plurality of antenna coils are connected to the automatic guided vehicle. Are arranged in a row in the width direction, and the length of each antenna coil in the width direction is such that the coil at the center becomes the minimum width, and the antenna coil shape is such that the width of the coil becomes longer toward both ends. An automatic guided vehicle traveling system characterized by the following.