JP2020154373A - Cargo conveying and handling identification device - Google Patents

Abstract

To provide a cargo conveying and handling identification device capable of accurately identifying a gate passage skid, when conveying a cargo through an ID tag reading gate comprising an RFID tag reading device.SOLUTION: A cargo conveying and handling identification device, when identifying skids Sk1, Sk2 passing through an ID tag reading gate 2 comprising an RFID tag reading device 4, of a plurality of skids Sk1, Sk2, Sk3, ..., plots received data including the strength of a radio wave and the number of times of reception of the radio wave for information on RFID tags T1, T2, T3, ... read out by the RFID tag reading device 4, for each unit time. Then, the cargo conveying and handling identification device performs mathematical processing to the plotted received data, and discriminates between gate passage skids Sk1, Sk2 passing through the ID tag reading gate 2, and gate non-passage skids Sk3, Sk4, Sk5, Sk6 not passing through the ID tag reading gate 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a transport cargo handling identification device. In particular, the present invention relates to an improvement of a means for identifying a cargo handling that has passed through an ID tag reading gate provided with an RFID tag reading device among a plurality of cargo handling.

Conventionally, in an automobile production factory or the like, a plurality of parts boxes containing parts and a plurality of parts boxes (empty boxes) after parts are taken out are placed on a pallet and transported by a forklift. In the following, a form in which a plurality of parts boxes are placed on a pallet will be referred to as a skid.

To be able to identify which of the multiple skids existing in the factory is being transported by the forklift (identify the skid being transported) and determine whether or not proper skid transportation is being performed. It is desirable to keep it.

In Patent Document 1, an ID tag provided with an IC chip is attached to the side surface of the pallet, and pallet information (information that identifies a skid is specified by a reader / writer mounted on a forklift without contact from the ID tag. , Skid information) is read to identify the skid.

Japanese Unexamined Patent Publication No. 2008-285250

However, in the above-mentioned system (a system that identifies a skid by attaching an ID tag such as an RFID (Radio Frequency IDentification) tag to each pallet of a plurality of skids existing in the factory), the following May lead to the problems described in.

In the factory, there are many pallets on which different types of parts boxes are placed. Therefore, RFID tags storing different skid information are attached to each pallet. Then, the skid is passed through an ID tag reading gate (for example, a gate-type antenna facility; hereinafter, sometimes simply referred to as a gate), and the skid is attached to the pallet by a reader / writer (RFID tag reading device) provided in this gate. When reading skid information from an RFID tag, the RFID tag attached to the pallet around the gate (the pallet of the skid placed around the gate or the pallet of the skid carried near the gate) May also read skid information. In other words, the reader / writer reads not only the skid information of the relay passing through the gate (hereinafter referred to as the gate passing skid) but also the skid information of the skid not passing through the gate (hereinafter referred to as the gate non-passing skid). There is a possibility that it will end up. For this reason, it is difficult to accurately identify the gate passing skid, and there is a possibility that the gate non-passing skid may be mistakenly recognized as the gate passing skid.

In particular, when the skid information is read from the RFID tag by the reader / writer provided in the gate described above, the skid information can be read even if the position where the reader / writer is arranged and the position where the RFID tag is attached on the pallet are separated. If the radio wave output from the reader / writer is increased as much as possible, there is a high possibility that the skid information of the skid placed around the gate and the skid being transported near the gate will be read, and the skid passing through the gate will be read. It becomes difficult to accurately identify.

The present invention has been made in view of the above points, and an object of the present invention is to provide a transport cargo handling identification device capable of accurately identifying a gate-passing skid.

A solution of the present invention for achieving the above object is an RFID tag provided for cargo handling carried by an RFID tag reading device provided in the ID tag reading gate and passing through the ID tag reading gate. The target is a transport cargo handling specifying device for reading the information of the above and specifying the cargo handling carried by the transport device based on the read information. Then, this transport cargo handling identification device plots the received data including the strength of the radio wave of the information of the RFID tag read by the RFID tag reading device and the number of times the radio wave is received for each unit time, and the plotted said. It is characterized by including a cargo handling discriminating unit that performs mathematical processing on the received data to discriminate between cargo handling that has passed through the ID tag reading gate and cargo handling that has not passed through the ID tag reading gate.

When the RFID tag reading device reads the information of the RFID tag provided for the cargo handling carried by the transport device and passing through the ID tag reading gate, only the information of the RFID tag provided for the cargo handling passing through the ID tag reading gate is used. Therefore, there is a possibility that the information of the RFID tag provided in the cargo handling near the ID tag reading gate (the cargo handling not passing through the ID tag reading gate) is also read. In the present solution, even in such a situation, the reception data including the strength of the radio wave of the RFID tag information read by the RFID tag reader and the number of times the radio wave is received is plotted for each unit time, and the reception data is plotted. Mathematical processing is performed on the plotted received data to discriminate between cargo handling that has passed through the ID tag reading gate and cargo handling that has not passed through the ID tag reading gate. As a result, it is possible to improve the accuracy of identifying the cargo handling that has passed through the ID tag reading gate.

In the present invention, received data including the strength of the radio wave of the RFID tag information read by the RFID tag reader and the number of times the radio wave is received is plotted for each unit time, and the received data is mathematically processed to obtain an ID. The cargo handling that has passed through the tag reading gate and the cargo handling that has not passed through the ID tag reading gate are discriminated from each other. Therefore, it is possible to improve the accuracy of identifying the cargo handling that has passed through the ID tag reading gate.

It is a figure which shows the outline of the gate installation position in the factory which concerns on embodiment, and the periphery thereof. It is a perspective view which shows one skid. It is a block diagram which shows the schematic structure of the transport cargo handling identification apparatus. It is a flowchart which shows the procedure of the gate passage skid identification processing. It is a figure for demonstrating the outline of the data filling process and the mathematical process for tag data. It is a figure which shows an example of the transition of the reception intensity of the tag data of a gate passing skid. It is a figure which shows an example of the transition of the reception intensity of the tag data of the gate non-passing skid. It is a figure which shows an example of the difference value of the reception strength of the tag data shown in FIG. It is a figure which shows an example of the difference value of the reception strength of the tag data shown in FIG. 7. It is a figure which shows an example of the transition of the response number of the tag data of a gate passing skid. It is a figure which shows an example of the transition of the response number of the tag data of a gate non-passing skid. It is a figure which shows an example of the cumulative number of the response times of each tag data. It is a figure which shows an example of the calculation result of the Fourier amplitude of each frequency band after the Fourier transform of each of the tag data of the gate passing skid and the tag data of the gate non-passing skid.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, in an automobile production factory, skids (cargo handling) formed by placing a plurality of parts boxes on a pallet are loaded in a plurality of stages and transported by a forklift, and the skids being transported are specified. , A case where the skid is passed through a gate (gate type antenna equipment; ID tag reading gate) will be described.

Specifically, parts used in the production of automobiles are delivered to the factory premises by truck from a supplier or a distribution relay point. The package of the delivered parts is a skid Sk (Sk1, Sk2, Sk3, ...) in which a plurality of parts boxes 3, 3, ... In which the parts are housed are placed on a pallet P (P1, P2, P3, ...). ...) (see FIG. 1). The transport cargo handling identification device 1 according to the present embodiment passes the skid Sk through the gate 2 while being transported by the forklift 10, so that the RFID tags T (T1, T2, 2) attached to the side surface of the pallet P are attached. (T3, ...) Is read to identify which of the plurality of skids Sk1, Sk2, Sk3, ... Existing in the factory has passed through the gate 2 by being conveyed by the forklift 10 (passing through the gate). The purpose is to identify the skid) so that it can be determined whether or not proper skid transportation is being carried out.

In the following, when a plurality of skid Sks are individually described, Sk1, Sk2, Sk3, ... Are added as codes of the skid Sks, and when a plurality of palettes P are individually described, they are used as the codes of the palettes P. When P1, P2, P3, ... Are attached and the RFID tags T attached to the side surfaces of the plurality of pallets P are individually described, T1, T2, T3, ... Are attached as the codes of the RFID tags T. I will do it.

As shown in FIG. 1 (a diagram showing an outline of the gate installation position and its surroundings in the factory according to the present embodiment), the predetermined skids Sk1 and Sk2 among the plurality of skids Sk1, Sk2, Sk3, ... Are determined by the forklift 10. It is transported and passes through the gate 2. These skids Sk1 and Sk2 are gate-passing skids.

On the other hand, a plurality of skids Sk3 and Sk4 are placed around the gate 2 without being transported. Further, the skids Sk5 and Sk6 conveyed by the forklift 10'are conveyed near the gate 2 without passing through the gate 2. These skids Sk3, Sk4, Sk5, Sk6 are gate non-passing skids.

As described above, when the RFID tag T is read, the skid information (gate-passing skid) Sk1 and Sk2 during transportation passing through the gate 2 (gate-passing skid Sk1 and Sk2 are attached to the pallets P1 and P2). Not only the information stored in the RFID tags T1 and T2, but also the skid information (gate non-passing skid Sk3) that does not pass through the gate 2 (gate non-passing skid) Sk3, Sk4, Sk5, Sk6 (gate non-passing skid Sk3). The information stored in the RFID tags T3, T4, T5, and T6 attached to the palettes P3, P4, P5, and P6 of Sk4, Sk5, and Sk6 may also be read. Even in a situation where the transport cargo handling identification device 1 according to the present embodiment also reads the skid information of the gate non-passing skids Sk3, Sk4, Sk5, Sk6 in this way, the gate passing skids Sk1, Sk2 and the gate non-passing skids It is possible to discriminate between Sk3, Sk4, Sk5, and Sk6. Hereinafter, a specific description will be given.

-Skid-
FIG. 2 is a diagram showing an example of a skid Sk. As shown in FIG. 2, the pallet P has a plurality of parts boxes 3, 3, ..., And a pair of fork pockets FP, FP for inserting a fork of a forklift (not shown) on each side surface. It is provided. An RFID tag T is attached to one end of the side surface. Each RFID tag T (T1, T2, T3, ...) Attached to each of the plurality of pallets P (P1, P2, P3, ...) Has a different ID, and the RFID tag T (T1) , T2, T3, ...), Each of the plurality of palettes P can be individually recognized (the palette P is specified).

-Outline configuration of transport cargo handling identification device-
As shown in FIG. 1, the transport cargo handling identification device 1 according to the present embodiment allows a plurality of skids Sk1 and Sk2 transported by the forklift 10 to pass through the gate 2, thereby passing the pallets P1 of each skid Sk1 and Sk2. , P2 is a system that reads RFID tags T1 and T2 attached to the side surfaces of each.

The gate 2 is composed of a gate-shaped antenna facility, and both are provided with columns 21 and 21 erected on the floor surface (floor surfaces on both sides of the traveling path F1 of the forklift 10). Since the space between the columns 21 and 21 is the passage space for the forklift 10, the distance between the columns 21 and 21 is the width dimension of the forklift 10 and the skid Sk (orthogonal to the extending direction of the traveling path F1). It is set larger than the horizontal dimension).

RFID tag reading devices 4, 4, ... Are arranged at two locations in the vertical direction on the side surfaces of the columns 21 and 21 facing the traveling path F1. The RFID tag reading device 4 is for reading the RFID tags T1 and T2 attached to the side surfaces of the pallets P1 and P2. That is, when the forklift 10 on which the skids Sk1 and Sk2 are placed passes through the gate 2 (passes through the traveling path F1 between the columns 21 and 21), the RFID tag reading device 4 causes the side surfaces of the pallets P1 and P2. The RFID tags T1 and T2 attached to the are read. The number of RFID tag readers 4 installed is not limited to those described above.

FIG. 3 is a block diagram showing a schematic configuration of the transport cargo handling identification device 1. As shown in FIG. 3, the transport cargo handling identification device 1 includes a host computer 5, the RFID tag reading devices 4, 4, ... Arranged in the gate 2, and a plurality of pallets P1, P2, P3, ... (FIG. 1). The RFID tags T1, T2, T3, ... Are attached to each of them.

The RFID tag reading device 4 includes a reader / writer (tag reader) 41 for reading information on RFID tags T1, T2, T3, .... The reader / writer 41 includes an antenna 42 and an RFID tag reading unit 43. The antenna 42 receives (reads) data (information) from RFID tags T1, T2, T3, ... Existing in the reading area (radio wave receiving area). Further, the antenna 42 is a dipole antenna, and a plurality of the antennas 42 may be provided as needed.

The RFID tag reading unit 43 reads the information (information for specifying (identifying) the palette P, etc.) held by the RFID tags T1, T2, T3, ... Through the antenna 42.

Passage sensors 61 and 62 are installed on both sides of the gate 2 in the extending direction of the traveling path F1 (upstream side and downstream side in the traveling direction of the forklift 10) (see FIG. 1). These passage sensors 61 and 62 detect the passage of the forklift 10 on the travel path F1. The passage sensors 61 and 62 optically detect the passage of the forklift 10 and include a light emitting / receiving device toward the traveling path F1 to detect the presence / absence of reflected light by the reflector provided in the forklift 10. By detecting it, the passage of the forklift 10 is detected. Then, when the first passage sensor 61 installed on the upstream side detects the passage of the forklift 10, it transmits a passage detection signal to the RFID tag readers 4, 4, ..., And these RFID tag readers 4 , 4, ... Start the reading operation of the RFID tags T1, T2, T3, .... Further, when the second passage sensor 62 installed on the downstream side detects the passage of the forklift 10, the passage detection signal is transmitted to the RFID tag readers 4, 4, ..., And these RFID tag readers 4 , 4, ... Ends the reading operation of the RFID tags T1, T2, T3, ...

Further, the distance between the first passing sensor 61 and the gate 2 (the distance along the extending direction of the traveling path F1) and the distance between the second passing sensor 62 and the gate 2 (the distance of the traveling path F1). Distance along the extending direction) is approximately equal. Therefore, when the forklift 10 travels at a constant speed from the front position of the first pass sensor 61 to the front position of the second pass sensor 62, the timing when the first pass sensor 61 detects the passage of the forklift 10 The skids Sk1 and Sk2 pass through the gate 2 at a timing substantially intermediate to the timing when the second passage sensor 62 detects the passage of the forklift 10.

The operation of reading the information of the RFID tags T1, T2, T3, ... By the reader / writer 41 is set to read the information every predetermined time (for example, every 1 sec). In this embodiment, since a plurality of RFID tag readers 4, 4, ... Are arranged, the RFID tags T1, T2, T3, ... By the reader / writer 41 in these RFID tag readers 4, 4, ... It is preferable that the reading timings of the information in are synchronized.

Further, the gate 2 includes a tag information transmitting unit 22. When the RFID tag reading device 4 reads the information of the RFID tags T1, T2, T3, ... By the reader / writer 41, each information of the RFID tags T1, T2, T3, ... And the reading timing (time) The information is associated with the information and transmitted to the tag information transmission unit 22. The tag information transmission unit 22 transmits the information received from each RFID tag reading device 4 to the host computer 5.

A database DB is connected to the host computer 5. In this database DB, information on each of a plurality of skid skis in the factory (information on the type and number of parts housed in each parts box 3, 3, ..., information on the supplier of the parts, etc.) is collected. Is remembered.

Further, the host computer 5 determines the skid based on the tag information receiving unit 51 that receives the information transmitted from the tag information transmitting unit 22 and the received information (gate passing skids Sk1 and Sk2 and the gate non-gate). A skid discriminating unit (cargo handling discriminating unit) 52 (which discriminates between passing skids Sk3, Sk4, Sk5, and Sk6) is provided.

The skid discrimination unit 52 performs mathematical processing on the information to discriminate between the gate-passing skids Sk1 and Sk2 and the gate non-passing skids Sk3, Sk4, Sk5 and Sk6 (for specific mathematical processing, the skid discrimination unit 52 discriminates between them. Will be described later).

-Communication by RFID-
Here, the communication performed between the reader / writer 41 and the RFID tags T1, T2, T3, ... Will be described. This communication is a short-range wireless communication, which is a radio wave system and uses an RFID system in the UHF (Ultra High Frequency) band. For example, in the ultra-high frequency frequency band of 860 to 960 MHz, communication is performed within a range of about several meters. It is also possible to use various RFID systems such as an HF (High Frequency) band RFID system which is an electromagnetic induction system.

Further, the RFID tags T1, T2, T3, ... Are well known to include an RFID IC chip having a memory circuit, a logic circuit, and the like, and an antenna element connected to the IC chip. A dipole antenna is used as the antenna element.

A radio wave is transmitted from the antenna 42 of the reader / writer 41 to the surroundings, and the RFID tags T1, T2, T3, ... Existing in the area where the radio wave reaches receive the radio wave. Along with this, a current flows through the circuits inside the RFID tags T1, T2, T3, ..., And the information stored in the IC chip is signalized. Then, this signalized information is transmitted from the RFID tags T1, T2, T3, ... To the antenna 42 of the reader / writer 41. Then, when the antenna 42 of the reader / writer 41 receives the signal from the RFID tags T1, T2, T3, ..., The received signal is transmitted to the RFID tag reading unit 43, so that the RFID tags T1, T2, T3, ... ... information will be acquired (read).

-Gate-passing skid identification process-
Next, the gate-passing skid identification process, which is a feature of the present embodiment, will be described. This gate-passing skid identification process is a process for identifying the gate-passing skids Sk1 and Sk2 by discriminating between the gate-passing skids Sk1 and Sk2 and the gate non-passing skids Sk3, Sk4, Sk5 and Sk6.

As an outline of the gate passing skid identification process, the first passing sensor 61 detects the passage of the forklift 10 and the RFID tag reading devices 4, 4, ... Start the reading operation of the RFID tags T1, T2, T3, ... After that, the unit time is within the period until the second passage sensor 62 detects the passage of the forklift 10 and the reading operation of the RFID tags T1, T2, T3, ... By the RFID tag readers 4, 4, ... Is completed. For each, the intensity of the radio wave of the information of the RFID tags T1, T2, T3, ... Read by the RFID tag reading devices 4, 4, ... And the number of times the radio frequency is received (the number of responses) are plotted as received data. Then, the plotted received data (radio wave intensity of the information of RFID tags T1, T2, T3, ... And the number of times the radio wave is received) is mathematically processed, and the gate passing skid Sk1, which is the cargo handling that has passed through the gate 2, is performed. The Sk2 and the gate non-passing skids Sk3, Sk4, Sk5, Sk6, which are cargo handling that has not passed through the gate 2, are discriminated from each other. Hereinafter, a specific description will be given.

Examples of this mathematical processing include differential processing and Fourier transform processing of received data. Statistical values are calculated by this mathematical processing, and based on the statistical values, characteristic parts of received data corresponding to gate-passing skids Sk1 and Sk2. By extracting the feature parts that do not appear in the received data corresponding to the gate non-passing skids Sk3, Sk4, Sk5, Sk6, the gate-passing skids Sk1, Sk2 and the gate non-passing skids Sk3, Sk4, Sk5, Sk6 And, the gate passing skids Sk1 and Sk2 are specified. Hereinafter, the gate passage skid identification process will be specifically described.

FIG. 4 is a flowchart showing the procedure of the gate passage skid identification process. The processing of this flowchart is started with the first passage sensor 61 detecting the passage of the forklift 10 as a trigger.

First, in step ST1, the data received from the RFID tags T1, T2, T3, ... At predetermined time intervals after the reading operation of the RFID tags T1, T2, T3, ... By the RFID tag reading devices 4, 4, ... Is started. Acquire (tag data). The tag data (skid information) acquired here is not limited to those acquired from the gate-passing skids Sk1 and Sk2 (RFID tags T1 and T2), but also the gate non-passing skids Sk3, Sk4, Sk5 and Sk6 (RFID tags). It is possible that those obtained from T3, T4, T5, T6) are also included.

After acquiring the tag data in this way, the process proceeds to step ST2, and data that complements the unacquired part of each tag data (the part of the time zone when the tag data was not acquired) in order to enable the mathematical processing described later. Perform fill-in-the-blank processing. This data fill-in-the-blank process is performed by linearly interpolating the data of the unacquired portion with respect to the series of tag data acquired in step ST1.

After that, the process proceeds to step ST3, and mathematical processing is executed for each tag data (including tag data that has been filled in with data).

FIG. 5 is a diagram for explaining the outline of data fill-in-the-blank processing and mathematical processing for tag data. As shown in FIG. 5, in these processes, after reading each tag data (process A), fill-in-the-blank data is created for these tag data by the data fill-in-the-blank process described above (process B), and the data is subjected to the fill-in-the-blank data. And differential processing is performed to create differential data (process C). Further, the Fourier transform process is performed on the differential data to create the Fourier data (process E). Similarly, the Fourier transform process is performed on the fill-in-the-blank data to create the Fourier data (process D).

In step ST4, the statistical value of the data after the mathematical processing is calculated. This statistical value is parameterized with values such as the strength of the radio wave of the information of the RFID tags T1, T2, T3, ... And the maximum value, the minimum value, the average value, the standard deviation, the dispersion value, and the cumulative number of the reception times of the radio wave. It is calculated as.

Then, in step ST5, the skids Sk to which the RFID tags T1 and T2 that transmit the tag data corresponding to the statistical values are extracted by extracting the values peculiar to the gate passing skids Sk1 and Sk2 from the statistical values are attached. Discrimination and analysis are performed to identify the skids Sk1 and Sk2 passing through the gate.

Then, as a result of the discrimination and analysis, the skids Sk to which the RFID tags T1 and T2 that transmit the tag data corresponding to the statistical values peculiar to the gate passing skids Sk1 and Sk2 are attached are designated as the gate passing skids Sk1 and Sk2. The skid Sk to which the RFID tags T3, T4, T5, and T6 that have been identified and transmitted the other tag data are attached is specified as the gate non-passing skid Sk3, Sk4, Sk5, Sk6.

Hereinafter, the above-mentioned mathematical processing will be described more specifically. As the mathematical processing, as described above, the mathematical processing is performed on the strength of the radio wave of the information of the RFID tags T1, T2, T3, ... And the number of times the radio wave is received. Hereinafter, the mathematical processing for the strength of the radio wave and the mathematical processing for the number of times the radio wave is received will be described. Here, in order to simplify the explanation of the mathematical processing and facilitate the understanding of the invention, the tag data (two types of tag data) acquired from the RFID tags T1 and T2 of the gate passing skids Sk1 and Sk2 described above are used. A case of processing the tag data (four types of tag data) acquired from the RFID tags T3, T4, T5, and T6 of the gate non-passing skids Sk3, Sk4, Sk5, and Sk6 will be described.

<Mathematical processing for radio wave strength>
First, mathematical processing for the strength of radio waves will be described. FIG. 6 is a diagram showing an example of changes in the reception intensity of the tag data of the gate-passing skids Sk1 and Sk2. Further, FIG. 7 is a diagram showing an example of a transition of the reception intensity of the tag data of the gate non-passing skids Sk3, Sk4, Sk5, Sk6. The timing t1 in these figures is the timing when the first passage sensor 61 detects the passage of the forklift 10 and the RFID tag reading devices 4, 4, ... Start reading the RFID tags T1, T2, T3, ... is there. Further, the timing t2 in these figures is the timing at which the second passing sensor 62 detects the passage of the forklift 10 and the reading operation of the RFID tags T1, T2, T3, ... By the RFID tag reading devices 4, 4, ... Is. Hereinafter, this period (the period from the start of the reading operation of the RFID tags T1, T2, T3, ... By the RFID tag reading devices 4, 4, ... To the end of the reading operation) is referred to as a tag reading period.

When the leader / writer 41 of the RFID tag readers 4, 4, ... Actually reads the RFID tags T1, T2, T3, ..., The tag data of the gate-passing skids Sk1, Sk2 shown in FIG. 6 The reception strength information and the reception strength information of the tag data of the gate non-passing skids Sk3, Sk4, Sk5, Sk6 shown in FIG. 7 are mixed, but here, it is easy to understand the characteristics of these tag data. In order to do so, each information will be represented individually and explained below. The tag data of the reception strength shown in FIGS. 6 and 7 is the tag data before the data filling process is performed. Further, “●” in FIG. 6 is tag data from the RFID tag T1 attached to the pallet P1 of the gate passing skid Sk1, and “■” is the RFID attached to the pallet P2 of the gate passing skid Sk2. It is the tag data from the tag T2. Further, "○" in FIG. 7 is tag data from the RFID tag T3 attached to the pallet P3 of the gate non-passing skid Sk3, and "□" is attached to the pallet P4 of the gate non-passing skid Sk4. The tag data is from the RFID tag T4, "△" is the tag data from the RFID tag T5 attached to the pallet P5 of the gate non-passing skid Sk5, and "x" is the pallet of the gate non-passing skid Sk6. It is the tag data from the RFID tag T6 attached to P6.

As shown in FIG. 6, as for the transition of the reception intensity of the tag data of the gate-passing skids Sk1 and Sk2, the reception intensity is extremely high at a time substantially in the middle of the tag reading period. This is because when the gate-passing skids Sk1 and Sk2 pass through the gate 2, the gate-passing skids Sk1 and Sk2 are closest to the gate 2 at a time approximately in the middle of the tag reading period, and the RFID tags T1 and T2 and the antenna of the reader / writer 41 This is because the reception intensity is increased by the shortest distance from the 42. This is because, as described above, the distance between the first pass sensor 61 and the gate 2 (the distance in the direction along the extending direction of the traveling path F1) and the distance between the second pass sensor 62 and the gate 2 The distance (distance along the extending direction of the traveling path F1) is substantially equal, and the second passing sensor 62 detects the passage of the forklift 10 from the timing t1 when the first passing sensor 61 detects the passage of the forklift 10. This is due to the fact that the skids Sk1 and Sk2 pass through the gate 2 at a time substantially in the middle of the period up to the timing t2.

On the other hand, as shown in FIG. 7, as for the transition of the reception strength of the tag data of the gate non-passing skids Sk3 and Sk4, the reception strength does not change significantly over the entire tag reading period. This is because the skids Sk3 and Sk4 are placed around the gate 2 without being transported, and the distance between the RFID tags T3 and T4 of the skids Sk3 and Sk4 that do not pass through the gate and the antenna 42 of the reader / writer 41 does not change. This is because the reception intensity does not fluctuate significantly.

Further, as shown in FIG. 7, the transition of the reception strength of the tag data of the gate non-passing skids Sk5 and Sk6 is different from the transition of the reception strength of the tag data of the gate passing skids Sk1 and Sk2 shown in FIG. , The reception strength is extremely high in the first half and the second half of the tag reading period. This is because the gate non-passing skids Sk5 and Sk6 are transported near the gate 2 in the first half and the second half of the tag reading period, and at this time, the RFID tags T5 and T6 of the gate non-passing skids Sk5 and Sk6 and the antenna 42 of the reader / writer 41 This is because the reception intensity is increased by shortening the distance between the two.

As described above, the transition of the tag data reception intensity is different between the gate passing skids Sk1 and Sk2 and the gate non-passing skids Sk3, Sk4, Sk5 and Sk6.

FIG. 8 is a diagram showing an example of the difference value of the reception strength of the tag data shown in FIG. Further, FIG. 9 is a diagram showing an example of a difference value of the reception strength of the tag data shown in FIG. 7. The difference value of these reception intensities is obtained by differentiating the reception intensities of the tag data.

As shown in FIG. 8, as the difference value of the reception intensity of the tag data of the gate passing skids Sk1 and Sk2, a positive value and a negative value are switched at a time substantially in the middle of the tag reading period, and peaks before and after this switching. The absolute value of the value is also a large value. This is because, in FIG. 6, the reception strength of the tag data of the gate-passing skids Sk1 and Sk2 becomes extremely high at a time substantially in the middle of the tag reading period.

On the other hand, as shown in FIG. 9, as the difference value of the reception strength of the tag data of the gate non-passing skids Sk3, Sk4, Sk5, Sk6, a positive value and a negative value are obtained at a time substantially in the middle of the tag reading period. There is no switching, and no large peak value appears before and after this approximately intermediate time point. This is because, in FIG. 7, the reception strength of the tag data of the gate non-passing skids Sk5 and Sk6 does not become extremely high at a time substantially in the middle of the tag reading period. More specifically, most of the difference values of the reception strengths of the tag data of the gate non-passing skids Sk3 and Sk4 are around "0". Further, as the difference value of the reception strength of the tag data of the gate non-passing skids Sk5 and Sk6, a positive value and a negative value are switched in a period other than a time point substantially in the middle of the tag reading period.

Comparing the difference values of the reception strength of the tag data in this way, the difference value of the reception strength of the tag data in the gate passing skids Sk1 and Sk2 and the reception strength of the tag data in the gate non-passing skids Sk3, Sk4, Sk5 and Sk6 are compared. It is significantly different from the difference value of, and the characteristics of the tag data in the gate-passing skids Sk1 and Sk2 appear.

<Mathematical processing for the number of times radio waves are received>
Next, mathematical processing for the number of times radio waves are received will be described. FIG. 10 is a diagram showing an example of the transition of the number of receptions (number of responses) of the tag data of the gate passage skids Sk1 and Sk2. Further, FIG. 11 is a diagram showing an example of a transition of the number of receptions (number of responses) of tag data of the gate non-passing skids Sk3, Sk4, Sk5, Sk6. Also in these figures, the timing t1 detects the passage of the forklift 10 by the first passage sensor 61, and the RFID tag reading devices 4, 4, ... Start the reading operation of the RFID tags T1, T2, T3, ... It's timing. Further, the timing t2 in these figures is the timing at which the second passage sensor 62 detects the passage of the forklift 10 and the reading operation of the RFID tags T1, T2, T3, ... By the RFID tag reading devices 4, 4, ... Is.

As shown in FIG. 10, as for the transition of the number of times of receiving the tag data of the gate passing skids Sk1 and Sk2, the number of times of receiving is extremely large at a time substantially in the middle of the tag reading period. This is because when the gate-passing skids Sk1 and Sk2 pass through the gate 2, the gate-passing skids Sk1 and Sk2 are closest to the gate 2 at about the middle of the tag reading period, and the RFID tags T1 and T2 and the antenna of the reader / writer 41 This is because the number of receptions increases as the distance from the 42 becomes the shortest.

On the other hand, as shown in FIG. 11, as for the transition of the number of times of receiving the tag data of the gate non-passing skids Sk3 and Sk4, the number of times of receiving does not change significantly over the entire tag reading period. This is because the skids Sk3 and Sk4 are placed around the gate 2 without being transported, and the distance between the RFID tags T3 and T4 of the gate non-passing skids Sk3 and Sk4 and the antenna 42 of the reader / writer 41 does not change. This is because the number of receptions does not fluctuate significantly.

Further, as shown in FIG. 11, the transition of the number of times of receiving the tag data of the gate non-passing skids Sk5 and Sk6 is different from the transition of the number of times of receiving the tag data of the gate passing skids Sk1 and Sk2 shown in FIG. , The number of receptions is extremely large in the first half and the second half of the tag reading period. This is because the gate non-passing skids Sk5 and Sk6 are transported near the gate 2 in the first half and the second half of the tag reading period, and at this time, the RFID tags T5 and T6 of the gate non-passing skids Sk5 and Sk6 and the antenna 42 of the reader / writer 41 This is because the number of receptions increases as the distance between the two becomes shorter.

As described above, the transition of the number of times of receiving the tag data is different between the gate passing skids Sk1 and Sk2 and the gate non-passing skids Sk3, Sk4, Sk5 and Sk6.

FIG. 12 is a diagram showing an example of the cumulative number of receptions of each tag data. As shown in FIG. 12, the tag data of the gate non-passing skids Sk3 and Sk4 is compared with the cumulative number of receptions of the tag data of the gate passing skids Sk1 and Sk2 (the number of data receptions from the RFID tags T1 and T2). The cumulative number of receptions (number of data receptions from RFID tags T3 and T4) is extremely large, and the number of receptions of tag data of gate non-passing skids Sk5 and Sk6 (number of data receptions from RFID tags T5 and T6). The cumulative number of is extremely low.

Based on the above data, the maximum value and dispersion value for the reception strength of the tag data, and the maximum value and dispersion value for the number of times the tag data is received are calculated, and the gate passes from the values obtained by the discriminant using these. The skids Sk1 and Sk2 are discriminated from the gate non-passing skids Sk3, Sk4, Sk5 and Sk6.

The following formula (1) is the discriminant.

y = -aX1 + bX2-cX3 + dX4 + eX5 + f ... (1)
Here, X1 is the total number of times the tag data is received (cumulative number), X2 is the maximum value of the reception strength of the tag data, X3 is the dispersion value of the reception strength of the tag data, and X4 is the maximum value of the number of times the tag data is received. X5 is a distributed value of the number of times the tag data is received. Further, a to e are coefficients corresponding to each value, and f is a constant obtained in advance by an experiment or the like. The term of the discriminant is not limited to these, and the average value or standard deviation may be used as described above.

Then, if the calculated value (statistical value) y calculated by this discriminant is equal to or greater than a predetermined threshold value, it is determined that the tag data of the gate passing skids Sk1 and Sk2 is used, and the calculated value y is predetermined. If it is less than the threshold value of, it is judged that it is based on the tag data of the gate non-passing skids Sk3, Sk4, Sk5, Sk6. The threshold value is a value obtained by experiments or the like.

FIG. 13 is a diagram showing an example of the calculation result of the Fourier amplitude of each frequency band after the Fourier transform of the tag data of the gate passing skids Sk1 and Sk2 and the tag data of the gate non-passing skids Sk3, Sk4, Sk5 and Sk6. .. In each of the underlined frequency bands f1 to f4, in order from the left side, gate passing skid Sk1, gate passing skid Sk2, gate non-passing skid Sk3, gate non-passing skid Sk4, gate non-passing skid Sk5, gate non-passing skid Sk6 It is each Fourier amplitude.

In the case of the present embodiment, especially in the frequency band f2, there is a large difference between the Fourier amplitude in the tag data of the gate passing skids Sk1 and Sk2 and the Fourier amplitude in the tag data of the gate non-passing skids Sk3, Sk4, Sk5 and Sk6. It has occurred, and the characteristics of the tag data of the gate-passing skids Sk1 and Sk2 appear.

-Effect of embodiment-
As described above, in the present embodiment, the strength of the radio wave of the information of the RFID tags T1, T2, T3, ... Read by the RFID tag readers 4, 4, ... And the number of times the radio wave is received for each unit time. The received data including the above is plotted, and the received data is subjected to mathematical processing. , Sk5, Sk6). Therefore, it is possible to improve the accuracy of identifying the gate-passing skids Sk1 and Sk2, and it is possible to make a highly reliable determination as to whether or not proper skid transport is performed.

In addition, it is not necessary to provide an anechoic chamber (an anechoic chamber having a radio wave absorber so as not to be affected by radio waves from the outside) at the gate in order to identify the skid passing through the gate, thereby reducing the cost of the equipment. You can also do it.

-Experimental example-
In order to confirm the above effect, the inventors of the present invention conducted an experiment. In this experiment, the ratio in which the gate-passing skid was properly specified was compared between the conventional transport cargo handling identification device and the transport cargo handling identification device 1 according to the present embodiment. For example, in a situation where there are about 3000 skids in the factory, about 1500 of them are passed through the gate in order, and the ratio of skids passing through the gate is compared.

In the case of the conventional transport cargo handling identification device, the ratio of properly identifying the gate-passing skid was about 50%. On the other hand, in the transport cargo handling identification device 1 according to the present embodiment, the ratio of properly identifying the gate-passing skid reached about 98%. As a result, the effect of the present invention was confirmed.

-Other embodiments-
The present invention is not limited to the above-described embodiment, and all modifications and applications included in the claims and the range equivalent to the claims can be applied.

For example, in the above-described embodiment, the case where the transport cargo handling identification device 1 according to the present invention is applied to an automobile production factory has been described. The present invention is not limited to this, and can be applied to production factories other than automobiles, and can also be applied to the transportation of articles in a warehouse (when a plurality of articles are placed and transported on a pallet). is there.

Further, in the above-described embodiment, one RFID tag T is attached to one pallet P. The present invention is not limited to this, and a plurality of RFID tags T may be attached to one pallet P. Thereby, the reliability of the reading operation of the RFID tag T can be improved.

Further, in the above-described embodiment, the case where the skid Sk is conveyed by the forklift 10 has been described as an example. The present invention is not limited to this, and can be applied to those that convey skids by a conveyor. That is, while transporting the skid by the conveyor, the skid is passed through the ID tag reading gate to read the RFID tag attached to the side surface of the pallet, and the gate among the plurality of skids existing in the factory. It identifies the passing skid.

The present invention is applicable to a transport handling identification device that identifies a skid that has passed through an ID tag reading gate provided with an RFID tag reading device.

1 Transport handling identification device 2 Gate (ID tag reading gate)
4 RFID tag reader 52 Skid discrimination unit (cargo handling discrimination unit)
10 Forklift (conveyor)
Sk skid (cargo handling)
T RFID tag

Claims (1)

The RFID tag reading device provided in the ID tag reading gate reads the information of the RFID tag provided for the cargo handling carried by the transport device and passes through the ID tag reading gate, and the transport device is based on the read information. Is a transport cargo handling identification device for identifying the cargo handling carried by
For each unit time, the received data including the radio wave intensity of the RFID tag information read by the RFID tag reader and the number of times the radio wave is received is plotted, and the plotted received data is mathematically processed. A transport cargo handling specifying device including a cargo handling discriminating unit that discriminates between cargo handling that has passed through the ID tag reading gate and cargo handling that has not passed through the ID tag reading gate.

Images