Access detection device

Abstract

To provide an access detection device capable of detecting the entry of a management object into a management object region with a simple configuration.SOLUTION: An access detection device 30 uses a tag 31 attached to a kindergarten child K and a reader 32 having an antenna 33 for transmitting and receiving radio waves to and from the tag 31 to detect the entry / exit of the kindergarten child K to / from a riding part 13. A detectable range AR of the tag 31 by the reader 32 is defined to include an entry / exit passage 19 that the kindergarten child K passes through when entering / exiting the riding part 13 through an entrance / exit 16, and a position of the antenna 33 is at the side of the entrance / exit 16 in the detectable range AR. An electronic controller 35 detects that the kindergarten child K has entered the riding part 13, provided that an increasing speed of the radio wave strength with respect to the radio wave is greater than a predetermined first threshold value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an entrance / exit detection device.

Background Art

[0002] In order to manage objects to be managed (for example, goods), it has been proposed to manage the entry and exit of objects to be managed into and out of a management target area (for example, a warehouse). As such a device, those having an RFID reader and an RFID tag are frequently used. The RFID reader has an antenna for transmitting and receiving radio waves to and from the RFID tag. The RFID tag is attached to the object to be managed. When the RFID tag receives radio waves from the RFID reader, it transmits radio waves to the RFID reader in response. In this device, it is possible to detect the presence of the RFID tag within the detectable range of the RFID tag by the RFID reader, specifically, within the transmission / reception range by the antenna.

[0003] As the above device, those provided with a plurality of RFID readers have been proposed (for example, Patent Document 1). In this device, the position of the RFID tag is estimated based on the relationship between the radio waves received by each of the plurality of RFID readers (specifically, their antennas), that is, the plurality of radio waves received for the same RFID tag.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the device described in Patent Document 1, by estimating the position of the RFID tag, it becomes possible to detect that the same RFID tag has entered the management target area or exited the management target area.

[0006] However, in the above device, in order to detect the entry and exit of one RFID tag, a plurality of RFID readers are required. Therefore, the structure of the device becomes complicated. Also, in the above device, a plurality of radio waves are used to detect the entry and exit of one RFID tag. Therefore, the control structure of the device also becomes complicated, such as the need to execute arithmetic processing for specifying the relationship between those radio waves.

Means for Solving the Problem

[0007] Each aspect of the device for solving the above problem will be described. [Aspect 1] An entry / exit detection device that detects the entry and exit of a management object with respect to a management target area by using an RFID tag attached to the management object and an RFID reader having an antenna for transmitting and receiving radio waves between the RFID tag, wherein the detectable range of the RFID tag by the RFID reader includes a passage area through which the management object passes when the management object enters and exits the management target area through an entrance / exit in the management target area, and the position of the antenna is determined to be a position on the entrance / exit side in the detectable range, and an entry detection unit that detects that the management object has entered the management target area on the condition that an increase rate of the radio wave intensity of the radio wave transmitted and received by the antenna becomes larger than a predetermined first threshold value.

[0008] In the above configuration, when the management object (specifically, the RFID tag) enters and exits the management target area (specifically, the detection range of the RFID reader), the amount of change in the radio wave intensity accompanying the movement is larger than when the management object moves within the management target area. Therefore, when the management object enters and exits the management target area, the rate of change in the radio wave intensity accompanying the movement of the management object also becomes larger under certain conditions of the movement amount and movement speed of the management object.

[0009] In addition, near the entrance and exit of the area to be managed, since the distance between the antenna of the RFID reader and the RFID tag is short, the radio wave intensity increases. Therefore, in the situation where the object to be managed enters or exits the area to be managed through the entrance and exit, it can be said that the rate of change of the radio wave intensity becomes particularly large.

[0010] According to the above configuration, based on the fact that the rate of increase in such radio wave intensity has become large, it is possible to accurately detect that the object to be managed has entered the area to be managed. Therefore, according to the above configuration, it is possible to detect the entry of the object to be managed into the area to be managed with a simple configuration of performing detection based on the radio wave intensity related to one RFID tag received by one RFID reader.

[0011] [Aspect 2] An entry / exit detection device according to [Aspect 1], comprising a presence detection unit that detects that the object to be managed is present in the area to be managed on the condition that after the rate of increase in the radio wave intensity becomes greater than the first threshold value, the rate of change in the radio wave intensity becomes smaller than a predetermined second threshold value.

[0012] In the above configuration, when the object to be managed moves in the area to be managed, the amount of change in the radio wave intensity accompanying the movement is smaller than when the object to be managed enters or exits the area to be managed. Therefore, when the object to be managed moves in the area to be managed, under certain conditions of the movement amount and movement speed of the object to be managed, the rate of change in the radio wave intensity accompanying the movement of the same object to be managed also becomes smaller.

[0013] According to the above configuration, after it is detected that the object to be managed has entered the area to be managed, based on the fact that the rate of change in the radio wave intensity has become smaller, it is possible to detect that the object to be managed is present in the area to be managed. Thereby, it is possible to accurately detect the entry of the object to be managed into the area to be managed.

[0014] [Aspect 3] An entrance / exit detection device according to [Aspect 1] or [Aspect 2], comprising an exit detection unit that detects that the object to be managed has exited the management target area on the condition that the rate of decrease in the radio wave intensity has become greater than a predetermined third threshold value.

[0015] [Aspect 4] An entrance / exit detection device that detects the entry and exit of the object to be managed with respect to the management target area by using an RFID tag attached to the object to be managed and an RFID reader having an antenna for transmitting and receiving radio waves with the RFID tag, wherein the detectable range of the RFID tag by the RFID reader includes a passage area through which the object to be managed passes when the object to be managed enters and exits the management target area through an entrance / exit in the management target area, and the position of the antenna is set to be a position on the entrance / exit side in the detectable range, and an exit detection unit that detects that the object to be managed has exited the management target area on the condition that the rate of decrease in the radio wave intensity of the radio wave transmitted and received by the antenna has become greater than a predetermined third threshold value.

[0016] According to the above [Aspect 3] and [Aspect 4], it is possible to accurately detect that the object to be managed has exited the management target area when the rate of decrease in the radio wave intensity described above increases. Therefore, it is possible to detect the exit of the object to be managed from the management target area with a simple configuration in which detection is performed based on the radio wave intensity related to one RFID tag received by one RFID reader.

[0017] [Aspect 5] The entrance / exit detection device according to any one of [Aspect 1] to [Aspect 4], wherein only one antenna is provided at a position on the entrance / exit side in the detectable range. According to the above configuration, it is possible to detect the entry or exit of the object to be managed with respect to the management target area through the entrance / exit with a simple configuration that uses one antenna provided at a position on the entrance / exit side in the detectable range.

[0018] [Aspect 6] The portion on the side of the entrance / exits including the entrance / exits in the management target area has a shape extending in a first direction towards which the transmission / reception surface of the antenna faces, and the antenna is provided so as to irradiate radio waves from one end to the other end of the portion in the first direction. The entrance / exits are provided at one end of the portion so that the management target object enters and exits the management target area from a second direction intersecting the first direction. The entrance / exit detection device according to any one of [Aspect 1] to [Aspect 5].

[0019] According to the above configuration, when the management target object enters and exits the management target area through the entrance / exits, the movement route of the management target object can be determined so that the change rate of the radio wave intensity becomes particularly large. Specifically, when the management target object enters and exits the management target area, the management target object can enter and exit from the second direction with respect to the end portion on the side of the entrance / exits in the management target area, that is, the portion where the radio wave intensity is high in the management target area. Thereby, in the management target area, in the portion where the radio wave intensity is likely to be high, when the management target object enters the management target area, it can be moved so as to approach the antenna, and when it exits the management target area, it can be moved so as to move away from the antenna. Therefore, in any case, the change rate of the radio wave intensity becomes large. Further, after the management target object once enters the management target range, the management target object can be moved in the first direction in the portion on the side of the entrance / exits in the management target area. In this case, the change rate of the radio wave intensity becomes relatively small.

[0020] [Aspect 7] The management target area is the passenger compartment of a bus vehicle operated for the purpose of sending and receiving children going to or from a kindergarten or nursery school, and the management target object is the child. The entrance / exit detection device according to any one of [Aspect 1] to [Aspect 6].

[0021] According to the above configuration, it is possible to detect the boarding and alighting of children on the bus vehicle for sending and receiving.

Advantages of the Invention

[0022] According to this embodiment, it is possible to detect the entry of a management target into the management target area with a simple configuration.

Brief Description of Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0024] Hereinafter, an embodiment of the entry / exit detection device will be described with reference to FIGS. 1 to 7. <Vehicle 10> First, the configuration of the vehicle to which the entry / exit detection device of this embodiment is applied will be described. In the following description, the forward direction of the vehicle is described as the front, and based on this, the front, rear, upper, lower, left, and right are defined.

[0025] As shown in Fig. 1, the vehicle 10 of the present embodiment is a bus vehicle operated for the purpose of picking up and dropping off children (hereinafter referred to as kindergarten children K) who attend kindergartens or nurseries. The passenger compartment 11 of the vehicle 10 has a driver's section 12 and a passenger section 13. The driver's section 12 constitutes the front part in the passenger compartment 11. A driver's seat 14 on which the driver sits is provided in the driver's section 12. The passenger section 13 constitutes the rear part in the passenger compartment 11. A rear seat 15 on which the kindergarten children K sit is provided in the passenger section 13. In the present embodiment, the passenger section 13 corresponds to the management target area, and the kindergarten children K correspond to the management target objects.

[0026] <Entrance / exit 16 and door 17> The vehicle 10 has an entrance / exit 16 that communicates the inside and outside of the passenger compartment 11, and a door 17 provided so as to be able to open and close the entrance / exit 16. The entrance / exit 16 and the door 17 are provided at a portion corresponding to the front end of the passenger section 13 on the left side of the vehicle 10. The door 17 is constituted by, for example, a sliding door. An opening / closing switch (not shown) is provided in the driver's section 12 and the door 17. Through the operation of this opening / closing switch, the door 17 performs an opening / closing operation. When the door 17 is opened, the kindergarten children K can get on and off the passenger section 13. Also, when the door 17 is closed, the kindergarten children K cannot get on and off the passenger section 13. A door sensor 18 for detecting the opening and closing of the door 17 is provided in the vehicle 10.

[0027] <Entrance / exit passage 19 and central passage 20> The passenger section 13 is provided with an entrance / exit passage 19 and a central passage 20 as passages for passengers. The entrance / exit passage 19 extends from the entrance / exit 16 to the middle position in the vehicle width direction in the passenger section 13 so as to extend in the vehicle width direction. The central passage 20 extends from the end on the side far from the entrance / exit 16 (specifically, the right side) in the entrance / exit passage 19 to the rear end portion of the passenger section 13 so as to extend in the front-rear direction. In the present embodiment, the passenger passage constituted by the entrance / exit passage 19 and the central passage 20 extends in an L shape inside the passenger section 13. In other words, the flow line of the passengers in the passenger section 13 forms an L shape.

[0028] <Rear seat 15> In the passenger compartment 13, a plurality (seven in this embodiment) of rear seats 15 are provided. The rear seats 15 are arranged on both sides of the central aisle 20 at intervals in the front-rear direction. Specifically, four rear seats 15 are provided on the right side of the central aisle 20, and three rear seats 15 are provided on the left side of the central aisle 20.

[0029] As shown by the arrow A in FIG. 1, when the child K getting on the vehicle passes through the entrance / exit 16, first, the child enters the access passage 19 in the passenger compartment 13. Then, after passing through this access passage 19, the child enters the central aisle 20 and moves along the central aisle 20, and sits on the rear seats 15 provided on both sides of the central aisle 20. In this way, the child K getting on the vehicle moves in the passenger compartment 13 along the route of "entrance / exit 16" → "access passage 19" → "central aisle 20" → "rear seat 15" and sits on the rear seat 15.

[0030] On the other hand, as shown by the arrow B in FIG. 1, the child K getting off the vehicle first moves along the central aisle 20 to reach the access passage 19. Then, the child moves the access passage 19 toward the entrance / exit 16 side, and exits to the outside of the passenger compartment 13 through the entrance / exit 16. In this way, the child K getting off the vehicle moves in the passenger compartment 13 along the route of "rear seat 15" → "central aisle 20" → "access passage 19" → "entrance / exit 16" and exits to the outside of the vehicle 10.

[0031] <Entrance / exit detection device 30> Next, the entrance / exit detection device 30 according to this embodiment will be described. As shown in FIGS. 1 and 2, the entrance / exit detection device 30 uses an RFID tag (hereinafter, tag 31) and an RFID reader (hereinafter, reader 32) to detect the entry and exit of the child K to and from the passenger compartment 13 of the passenger compartment 11. Note that "RFID" is an abbreviation of "Radio Frequency Identification".

[0032] <Tag 31> Tag 31 is attached to child K. Tag 31 is attached to, for example, the hat, bag, or water bottle of child K. Tag 31 has a memory unit that stores an identification code. This identification code includes an identification number used to identify child K who owns Tag 31. Tag 31 has an antenna unit that transmits and receives radio waves. In the detectable range AR where Tag 31 can be detected by reader 32, Tag 31 receives the radio waves irradiated from the reader 32. When Tag 31 receives radio waves from reader 32, it transmits, using the radio waves, the RSSI value (hereinafter referred to as radio wave intensity D), which is a value related to the intensity of the radio waves received at this time, and the identification code stored in advance in the memory unit, to reader 32. Note that "RSSI" is an abbreviation of "Received Signal Strength Indicator".

[0033] <Reader 32> Reader 32 includes antenna 33 and control unit 34. Antenna 33 is for transmitting and receiving radio waves with Tag 31. Antenna 33 transmits radio waves to the detectable range AR. Antenna 33 receives radio waves including the radio wave intensity D and the identification code transmitted from Tag 31. Antenna 33 is provided at the center in the vehicle width direction at the front end of the riding section 13 with the transmission and reception surface facing backward. In this embodiment, only one antenna 33 is provided. The position of antenna 33 is the position on the side of the entrance / exit 16 in the detectable range AR, specifically, the front end position of the detectable range AR. In this embodiment, radio waves are transmitted from antenna 33 backward.

[0034] Control unit 34 is provided in the driving unit 12. Antenna 33 is connected to control unit 34. Control unit 34 executes the operation control of antenna 33, such as executing the transmission and reception of radio waves by antenna 33. In addition, control unit 34 converts the radio waves received by antenna 33 into the radio wave intensity D and the identification code and takes them in.

[0035] In this embodiment, the detectable range AR is an access passage 19 which is a passage area through which the child K passes when entering and leaving the boarding section 13 of the passenger compartment 11 via the access 16, specifically, it includes the entire portion on the side of the central passage 20 in the access passage 19. In this embodiment, the detectable range AR is defined such that the child K always passes through the detectable range AR when entering and leaving the boarding section 13, that is, when getting on and off the vehicle 10. Further, the detectable range AR is defined to be within the passenger compartment 11.

[0036] The portion on the side of the access 16 including the access 16 in the boarding section 13 of the passenger compartment 11 has a shape extending in the first direction (in this embodiment, the front-rear direction) towards which the transmission / reception surface of the antenna 33 faces. In this embodiment, the entire boarding section 13 including the above portion has a shape extending in the front-rear direction. The antenna 33 is provided to irradiate radio waves from the front end to the rear end of the boarding section 13. The access 16 is provided at the front end portion of the boarding section 13 so that the child K can enter and leave the boarding section 13 from the second direction (in this embodiment, the vehicle width direction) intersecting the front-rear direction, specifically, so as to open towards the left side of the vehicle 10.

[0037] <Electronic control device 35> The access detection device 30 includes an electronic control unit 35. The electronic control unit 35 executes various controls related to the operation of the reader 32. The electronic control unit 35 has a CPU, a ROM, a RAM, and a storage unit 36 that stores various programs and data. The storage unit 36 is composed of a non-volatile memory such as a hard disk drive or a solid state drive that allows for random writing and reading. The reader 32, the door sensor 18, etc. are connected to the electronic control unit 35. The electronic control unit 35 captures various signals indicating the operating state of the reader 32, the radio wave intensity D and the identification code received by the reader 32, and the detection signal of the door sensor 18. The electronic control unit 35 is configured to execute various arithmetic processes based on various programs and data. Based on the calculation results, the electronic control unit 35 executes the operation control of the reader 32, the boarding detection control and the alighting detection control for detecting the entry and exit of the child K into and out of the boarding area 13 of the passenger compartment 11. In this embodiment, the electronic control unit 35 corresponds to an entry detection unit, an exit detection unit, and a presence detection unit.

[0038] <Boarding Detection Control> Hereinafter, the boarding detection control for detecting the boarding of the child K will be described. FIG. 3 shows an example of the transition of the radio wave intensity D received by the reader 32 when the child K boards the vehicle.

[0039] As shown in FIG. 3, before the child K boards the vehicle (before time t11), the tag 31 attached to the child K is outside the detectable range AR of the reader 32. Therefore, the reader 32 is in a state where it does not receive radio waves or the received radio wave intensity D is extremely small.

[0040] Then, when the door 17 is opened (time t11) and the child K boards the vehicle through the entrance / exit 16 (time t12), the child K enters the access passage 19. At this time, since the tag 31 attached to the child K enters the detectable range AR, the radio wave intensity D transmitted from the tag 31 and received by the reader 32 increases. As a result, the radio wave intensity D becomes equal to or greater than a predetermined value P.

[0041] Here, when the tag 31 enters the detectable range AR of the reader 32, the radio wave intensity D changes from "a very small value" to "a relatively large value". Therefore, in this case, compared with the case where the tag 31 moves within the detectable range AR, the amount of change in the radio wave intensity D accompanying the movement becomes larger. Thus, when the child K gets into the passenger compartment 13 of the vehicle 10, compared with the case where the child K moves within the same passenger compartment 13, the amount of increase in the radio wave intensity D accompanying the movement becomes larger. From this, it can be said that under the condition that the moving speed of the child K is constant, when the child K gets into the passenger compartment 13, compared with the case where the child K moves within the passenger compartment 13, the increasing speed of the radio wave intensity D accompanying the movement of the child K also becomes larger.

[0042] Also, in this embodiment, near the entrance / exit 16, since the distance between the reader 32 and the tag 31 attached to the child K is short, the radio wave intensity D becomes large. Therefore, in the situation where the child K gets into the passenger compartment 13 through the entrance / exit 16, since the radio wave intensity D changes from "a very small value" to "a large value", it can be said that the increasing speed of the radio wave intensity D becomes particularly large. From this, in this embodiment, when the tag 31 enters the detectable range AR through the entrance / exit 16, that is, when the child K gets into the passenger compartment 13, it can be seen that the increasing speed of the radio wave intensity D becomes large.

[0043] In this embodiment, when the child K moves at the rear part of the passenger compartment 13, the tag 31 may enter the detectable range AR from the rear end of the detectable range AR. Also in this case, the radio wave intensity D increases. However, the rear end of the detectable range AR is a part that is far from the reader 32. Therefore, when the tag 31 enters from the rear end of the detectable range AR, compared with the case where the tag 31 enters from the front part of the detectable range AR, the amount of increase in the radio wave intensity D becomes smaller and the increasing speed of the radio wave intensity D becomes smaller.

[0044] Based on this point, in the present embodiment, on the condition that the increase rate V1 of the radio wave intensity D becomes larger than a predetermined first threshold value, it is detected that the child K has entered the passenger compartment 13, and thus that the child K has boarded. In the present embodiment, as the increase rate V1 of the radio wave intensity D, the average increase rate of the radio wave intensity D in a predetermined period (for example, several hundred milliseconds) is periodically calculated through arithmetic processing by the electronic control unit 35. Also in the present embodiment, based on the results of various experiments and simulations by the inventors and the like, a value corresponding to the increase rate V1 of the radio wave intensity D and capable of accurately detecting that the child K has boarded when used as the first threshold value is obtained. And this obtained value is stored in advance in the storage unit 36 of the electronic control unit 35 as the first threshold value.

[0045] After the child K has boarded the passenger compartment 13 (after time t13 in FIG. 3), the child K passes through the access passage 19 (see FIG. 1) and reaches the central passage 20, and moves backward along the central passage 20 away from the reader 32. Along with this movement, the radio wave intensity D decreases. At this time, since the tag 31 attached to the child K moves inside the detectable range AR of the reader 32, the decrease rate of the radio wave intensity D becomes small. When the child K turns back and moves forward along the central passage 20, the radio wave intensity D increases. Also at this time, since the tag 31 moves within the detectable range AR, the increase rate of the radio wave intensity D becomes small. Further, when the child K sits on the rear seat 15, the movement of the tag 31 attached to the child K substantially stops, so the change rate of the radio wave intensity D becomes small. Thus, after the child K has boarded the passenger compartment 13, as long as the tag 31 moves inside the detectable range AR of the reader 32, the change rate of the radio wave intensity D, that is, the increase rate or the decrease rate, becomes small.

[0046] From this, in the present embodiment, it can be seen that when the tag 31 exists within the detectable range AR of the reader 32, that is, when the child K is in the passenger compartment 13, the change rate of the radio wave intensity D becomes small.

[0047] Based on this point, in the present embodiment, when the increase rate V1 of the radio wave intensity D becomes equal to or higher than the first threshold value, and then the change rate V2 of the same radio wave intensity D becomes smaller than the second threshold value, it is detected that the child K is present in the riding section 13. In the present embodiment, as the change rate V2 of the radio wave intensity D, the average change rate of the radio wave intensity D in a predetermined period (for example, several hundred milliseconds) determined in advance is periodically calculated through arithmetic processing by the electronic control device 35. In the present embodiment, based on the results of various experiments and simulations by the inventors and the like, a value corresponding to the change rate V2 of the radio wave intensity D and capable of accurately detecting that the child K is present in the riding section 13 when used as the second threshold value is obtained. And this obtained value is stored in advance in the storage unit 36 of the electronic control device 35 as the second threshold value.

[0048] Hereinafter, the process related to the boarding detection control (boarding detection control process) will be described in detail. FIG. 5 shows the execution procedure of the boarding detection control process. Note that the series of processes shown in the flowchart of the figure conceptually shows the execution procedure of the boarding detection control process, and the actual process is executed by the electronic control device 35 as a process at a predetermined cycle. The boarding detection control process is a process executed on the condition that the door 17 is open. The boarding detection control process is executed for each tag 31 detected by the reader 32.

[0049] As shown in FIG. 5, in this process, it is determined whether or not the following [Condition A] and [Condition B] are both satisfied (step S11). [Condition A] The tag 31 is detected by the reader 32.

[0050] [Condition B] Information regarding the identification code of the tag 31 detected by the reader 32 is not stored in the boarding list. And when at least one of [Condition A] and [Condition B] is not satisfied (step S11: NO), this process is once terminated without executing the following processes (processes in steps S12 to S15).

[0051] When both [Condition A] and [Condition B] are satisfied (Step S11: YES), it is determined whether all of the following Condition C (Step S12), Condition D (Step S13), and Condition E (Step S14) are satisfied.

[0052] [Condition C] The radio wave intensity D is equal to or greater than a predetermined value P. When this [Condition C] is satisfied (Step S12: YES), it is determined that the tag 31 exists within the detectable range AR, and it is determined that there is a possibility that the child K is in the passenger compartment 13.

[0053] [Condition D] After the door 17 is opened, there is a history in which the increase rate V1 of the radio wave intensity D becomes greater than the first threshold value. When this [Condition D] is satisfied (Step S13: YES), it is determined that the tag 31 has entered the passenger compartment 13 via the entrance / exit 16, and thus it is determined that the child K has boarded the passenger compartment 13.

[0054] [Condition E] After the above [Condition D] is satisfied, there is a history in which the change rate V2 of the radio wave intensity D becomes smaller than the second threshold value. When this [Condition E] is satisfied (Step S14: YES), it is determined that the child K has boarded and is in the passenger compartment 13.

[0055] And when all of [Condition C] to [Condition E] are satisfied (all of Steps S12 to S14 are "YES"), it is detected that the child K has boarded, and the process of Step S15 is executed. In the process of Step S15, as shown in FIG. 4, information regarding the boarding date and time and information regarding the identification code corresponding to the tag 31 (for example, the identification number, the name of the child K specified by the identification number, etc.) are stored in the boarding list.

[0056] Note that when at least one of [Condition C] to [Condition E] is not satisfied (any one of Steps S12 to S14 is "NO"), this process is once terminated without executing the process of Step S15.

[0057] <Alighting Detection Control> Next, the alighting detection control for detecting the alighting of child K will be described. FIG. 6 shows an example of the transition of the radio wave intensity D received by the reader 32 when child K alights.

[0058] As shown in FIG. 6, when child K is seated in the rear seat 15 (before time t21), the radio wave intensity D is higher than the predetermined value P, and the radio wave intensity D hardly changes. Then, when the door 17 is opened and child K gets out of the seat and moves forward along the central aisle 20 to alight (time t21 to t22), since the tag 31 attached to child K approaches the reader 32, the radio wave intensity D increases. However, at this time, since the tag 31 moves within the detectable range AR, the rate of increase of the radio wave intensity D is small. In addition, when child K turns back and moves backward along the central aisle 20, the radio wave intensity D decreases. Also at this time, since the tag 31 moves within the detectable range AR, the rate of decrease of the radio wave intensity D becomes small. Further, when child K is seated again in the rear seat 15, the movement of the tag 31 attached to child K substantially stops, so the rate of change of the radio wave intensity D becomes small. Thus, when child K is inside the passenger compartment 13, as long as the tag 31 moves inside the detectable range AR, the rate of change of the radio wave intensity D becomes small. From this, in the present embodiment, it can be seen that when the tag 31 exists within the detectable range AR of the reader 32, that is, when child K is in the passenger compartment 13, the rate of change of the radio wave intensity D becomes small.

[0059] After that, when child K passes through the access passage 19 and alights (time t22 to t23), the radio wave intensity D decreases. In the access passage 19, since the distance between the antenna 33 of the reader 32 and the tag 31 attached to child K becomes closer, the radio wave intensity D increases. Therefore, in the situation where child K alights after passing through the access passage 19, since the radio wave intensity D changes from a "large value" to a "very small value", it can be said that the rate of decrease of the radio wave intensity D becomes particularly large.

[0060] From this, in the present embodiment, when the tag 31 exits the detectable range AR through the access passage 19, that is, when the child K exits the boarding section 13 through the entrance / exit 16, it can be seen that the rate of decrease in the radio wave intensity D increases. In the present embodiment, as the child K moves at the rear of the boarding section 13, the tag 31 may exit from the rear end of the detectable range AR. Even in this case, the radio wave intensity D decreases. However, the rear end of the detectable range AR is a part that is far from the reader 32. Therefore, when the tag 31 exits from the rear end of the detectable range AR, compared with the case where the tag 31 exits from the front part of the detectable range AR, the amount of decrease in the radio wave intensity D decreases, and the rate of decrease in the radio wave intensity D becomes smaller.

[0061] Based on this point, in the present embodiment, on the condition that the rate of decrease V3 of the radio wave intensity D becomes larger than a predetermined third threshold value, it is detected that the tag 31 has exited the detectable range AR, and thus that the child K has gotten off the vehicle.

[0062] In the present embodiment, as the rate of decrease V3 of the radio wave intensity D, the average rate of decrease of the radio wave intensity D in a predetermined period (for example, several hundred milliseconds) is periodically calculated through arithmetic processing by the electronic control device 35. Also in the present embodiment, based on the results of various experiments and simulations by the inventors and the like, a value corresponding to the rate of decrease V3 of the radio wave intensity D and that enables accurate detection that the child K has gotten off the vehicle when used as the third threshold value has been obtained in advance. And this obtained value is stored in advance in the storage unit 36 of the electronic control device 35 as the third threshold value.

[0063] Hereinafter, the process related to the getting-off detection control (getting-off detection control process) will be described. Figure 7 shows the execution procedure of the alighting detection control process. Note that the series of processes shown in the flowchart of this figure conceptually shows the execution procedure of the alighting detection control process, and the actual process is executed by the electronic control unit 35 as a process for each predetermined cycle. This alighting detection control process is a process executed on the condition that the door 17 is open. The alighting detection control process is executed for each tag 31 detected by the reader 32.

[0064] As shown in Figure 7, in this process, it is determined whether both of the following [Condition F] and [Condition G] are satisfied (Step S21). [Condition F] After the door 17 is opened, the tag 31 is detected by the reader 32.

[0065] [Condition G] Information regarding the identification code of the tag 31 detected by the reader 32 is not stored in the alighting list. And when at least one of [Condition F] and [Condition G] is not satisfied (Step S21: NO), this process is temporarily terminated without executing the following processes (processes of Steps S22 to S24).

[0066] When both [Condition F] and [Condition G] are satisfied (Step S21: YES), it is determined whether both of the following Condition H (Step S22) and Condition J (Step S23) are satisfied.

[0067] [Condition H] After the door 17 is opened, there is a history in which the decreasing rate V3 of the radio wave intensity D becomes larger than the third threshold value. When this [Condition H] is satisfied (Step S22: YES), it is determined that the tag 31 has passed through the access passage 19 and exited from the detectable range AR, and thus it is determined that the child K has exited from the passenger compartment 13.

[0068] [Condition J] The radio wave intensity D is less than the predetermined value P. When this [Condition J] is satisfied (Step S23: YES), it is determined that the tag 31 does not exist within the detectable range AR, and it is determined that the child K is not in the passenger compartment 13.

[0069] When both [Condition H] and [Condition J] are satisfied (step S22: YES, and step S23: YES), it is detected that child K has gotten off the vehicle, and the process of step S24 is executed. In the process of step S24, as shown in FIG. 4, information regarding the date and time of getting off the vehicle and information regarding the identification code corresponding to tag 31 (for example, the identification number, the name of child K specified by the identification number, etc.) are stored in the getting-off list.

[0070] If at least one of [Condition H] and [Condition J] is not satisfied (step S22: NO, or step S23: NO), this process ends once without executing the process of step S24.

[0071] <Actions and Effects of this Embodiment> The actions and effects of this embodiment will be described. (1) The entry / exit detection device 30 uses tag 31 attached to child K and reader 32 having antenna 33 for transmitting and receiving radio waves to and from the tag 31 to detect the entry and exit of child K to and from the boarding section 13. The detectable range AR of tag 31 by reader 32 is defined so as to include the entry / exit passage 19 through which child K passes when entering and exiting the boarding section 13 via the entrance / exit 16, and the position of antenna 33 is at the position on the entrance / exit 16 side in the detectable range AR. The electronic control device 35 detects that child K has entered the boarding section 13 on the condition that the increase rate V1 of the radio wave intensity D has become greater than a predetermined first threshold value.

[0072] According to the above configuration, it is possible to accurately detect that child K has entered the boarding section 13 by the fact that the increase rate of the radio wave intensity D has increased. Therefore, it is possible to detect the entry of child K into the boarding section 13 with a simple configuration of performing detection based on the radio wave intensity D regarding one tag 31 received by one reader 32.

[0073] (2) On the condition that after the increase rate V1 of the radio wave intensity D becomes greater than the first threshold value, the change rate V2 of the radio wave intensity D becomes smaller than the second threshold value, it is possible to detect that the child K is present in the passenger compartment 13. As a result, since it can be seen that the child K has boarded the passenger compartment 13 and is in the same passenger compartment 13, it is possible to accurately detect that the child K has entered the passenger compartment 13 and, consequently, that the child K has boarded the vehicle.

[0074] (3) The electronic control device 35 detects that the child K has exited the passenger compartment 13 on the condition that the decrease rate V3 of the radio wave intensity D becomes greater than a predetermined third threshold value. According to the above configuration, it is possible to accurately detect that the child K has exited the passenger compartment 13 by the fact that the decrease rate of the radio wave intensity D has increased. Therefore, it is possible to detect the exit of the child K from the passenger compartment 13 with a simple configuration in which detection is performed based on the radio wave intensity D regarding one tag 31 received by one reader 32.

[0075] (4) With a simple configuration that utilizes one antenna 33 provided at a position on the side of the entrance / exit 16 within the detectable range AR, it is possible to detect the entry or exit of the child K with respect to the passenger compartment 13 through the entrance / exit 16.

[0076] (5) The entire passenger compartment 13 including the portion on the entrance / exit 16 side has a shape extending in the front-rear direction. The antenna 33 is provided so as to irradiate radio waves from the front end to the rear end of the passenger compartment 13. The entrance / exit 16 is provided at the front end portion of the passenger compartment 13 so that the child K can enter and exit the passenger compartment 13 from the vehicle width direction.

[0077] According to the above configuration, when the child K enters and exits the passenger compartment 13 through the entrance / exit 16, the movement route of the child K can be determined so that the rate of change of the radio wave intensity D becomes particularly large. Specifically, when the child K enters and exits the passenger compartment 13, the child K can enter and exit from the vehicle width direction with respect to the front end portion of the passenger compartment 13, that is, the portion where the radio wave intensity D in the passenger compartment 13 becomes large. Thereby, in the portion where the radio wave intensity D is likely to increase in the passenger compartment 13, when the child K enters the passenger compartment 13, the child K can be moved so as to approach the antenna 33, and when the child K exits the passenger compartment 13, the child K can be moved so as to move away from the antenna 33. In any case, the rate of change of the radio wave intensity D becomes large. Further, after the child K once enters the passenger compartment 13, the child K can be moved in the front-rear direction in the passenger compartment 13. In this case, the rate of change of the radio wave intensity D becomes relatively small.

[0078] <Modified Example> Note that the above embodiment can be implemented with the following modifications. The above embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

[0079] · As the increase rate V1 of the radio wave intensity D, if it is possible to accurately capture the occurrence of an event in which the increase rate of the radio wave intensity D becomes large when the child K gets on the vehicle, the average increase rate of the radio wave intensity D in an arbitrary period can be calculated. As the arbitrary period, for example, a period in which the radio wave intensity D changes from a first predetermined value to a second predetermined value larger than the first predetermined value can be defined.

[0080] · As the change rate V2 of the radio wave intensity D, if it is possible to accurately capture the occurrence of an event in which the change rate of the radio wave intensity D becomes small when the child K is in the passenger compartment 13, the average change rate of the radio wave intensity D in an arbitrary period can be calculated.

[0081] · In the boarding detection control process (Fig. 5), at least one of the processes in step S11, step S12, and step S14 may be omitted. · As for the decreasing speed V3 of the radio wave intensity D, if it is possible to accurately capture the occurrence of an event in which the decreasing speed of the radio wave intensity D increases when the child K gets off the vehicle, the average decreasing speed of the radio wave intensity D in an arbitrary period can be calculated. As the arbitrary period, for example, a period in which the radio wave intensity D changes from the third predetermined value to a fourth predetermined value smaller than the third predetermined value can be defined.

[0082] · In the getting-off detection control process (Fig. 7), one of the processes in step S21 and the process in step S23 may be omitted, or both may be omitted. · Only one of the boarding detection control process and the getting-off detection control process may be executed.

[0083] · The moving route of the child K in the boarding section 13 is not limited to an L shape, and can be of any shape. For example, the moving route of the child K in the boarding section 13 can be made into an I shape. In this case, the entrance / exit 16 of the boarding section 13 may be provided at one end in the direction in which the moving route in the boarding section 13 extends so that the child K enters and exits the boarding section 13 from the direction in which the moving route extends.

[0084] · The entrance / exit detection device according to the above embodiment is not limited to a bus vehicle operated for the purpose of sending and receiving children K, and can also be applied to a school bus operated for the purpose of sending and receiving students or pupils, a freight delivery vehicle operated for the purpose of delivering goods, etc.

[0085] When the entrance / exit detection device according to the above embodiment is applied to a school bus, students or pupils correspond to the objects to be managed, and the passenger compartment of the school bus corresponds to the management target area. According to the same configuration, it is possible to detect the entry and exit of students or pupils into and out of the passenger compartment of the school bus.

[0086] When applying the entry / exit detection device according to the above embodiment to a luggage delivery vehicle, the luggage to be delivered corresponds to the object to be managed, and the luggage compartment where the luggage is loaded corresponds to the area to be managed. According to this configuration, it is possible to detect the entry and exit of luggage in the luggage compartment of the luggage delivery vehicle. When applying the entry / exit detection device according to the above embodiment to a luggage delivery vehicle having a rear door, for example, the antenna 33 of the reader 32 can be provided at the rear end of the ceiling of the luggage compartment of the luggage delivery vehicle in a state of irradiating radio waves forward and obliquely downward.

[0087] · The entry / exit detection device according to the above embodiment can also be applied to a warehouse such as a logistics warehouse that temporarily stores luggage and goods. In this case, the luggage and goods correspond to the objects to be managed, and the storage space for storing the luggage and goods in the warehouse corresponds to the area to be managed. In this case, the antenna 33 of the reader 32 can be provided near the entrance / exit of the storage space in a state of irradiating radio waves toward the storage space. According to this configuration, it is possible to detect the entry and exit of luggage and goods in the storage space of the warehouse.

[0088] · The entry / exit detection device according to the above embodiment can also be applied to a vehicle or warehouse in which one area to be managed has a plurality of entrances and exits. In this case, the antenna 33 of the reader 32 can be provided separately for each of the plurality of entrances and exits. According to this configuration, it is possible to detect the entry and exit of the object to be managed for the area to be managed for each entrance and exit. Thereby, it becomes possible to detect the entry and exit of the object to be managed for the entire area to be managed.

Explanation of Signs

[0089] 10…Vehicle 11…Passenger Compartment 12…Driver's Section 13…Ride Area 14…Driver's Seat 15…Rear Seat 16…Entrance / Exit 17…Door 18…Door Sensor 19…Entry / Exit Passage 20…Central Passage 30…Entry / Exit Detection Device 31… Tag 32… Reader 33… Antenna 34… Control Unit 35… Electronic Control Device 36… Memory Unit

Claims

1. An access detection device that uses an RFID tag attached to an object to be managed and an RFID reader having an antenna for transmitting and receiving radio waves to and from the RFID tag, and detects the entry and exit of the object to be managed into and out of a management target area, the detectable range of the RFID tag by the RFID reader is determined so as to include a passage area through which the object to be managed passes when the object to be managed enters and exits the management target area through an entrance / exit in the management target area, and the position of the antenna is a position on the entrance / exit side in the detectable range, An access detection device comprising an entry detection unit that detects that the object to be managed has entered the management target area on the condition that the increase rate of the radio wave intensity of the radio wave transmitted and received by the antenna becomes greater than a predetermined first threshold value.

2. After the increase rate of the radio wave intensity becomes greater than the first threshold value, an existence detection unit that detects that the object to be managed exists in the management target area on the condition that the change rate of the radio wave intensity becomes smaller than a predetermined second threshold value, The access detection device according to claim 1.

3. An access detection device comprising an exit detection unit that detects that the object to be managed has exited the management target area on the condition that the decrease rate of the radio wave intensity becomes greater than a predetermined third threshold value. The access detection device according to claim 1 or 2.

4. An access detection device that uses an RFID tag attached to an object to be managed and an RFID reader having an antenna for transmitting and receiving radio waves to and from the RFID tag, and detects the entry and exit of the object to be managed into and out of a management target area, the detectable range of the RFID tag by the RFID reader is determined so as to include a passage area through which the object to be managed passes when the object to be managed enters and exits the management target area through an entrance / exit in the management target area, and the position of the antenna is a position on the entrance / exit side in the detectable range, An access detection device comprising an exit detection unit that detects that the object to be managed has exited the management target area on the condition that the decrease rate of the radio wave intensity of the radio wave transmitted and received by the antenna becomes greater than a predetermined third threshold value.

5. Only one antenna is provided at a position on the side of the entrance / exits within the detectable range. The entrance / exit detection device according to claim 1 or 4. **Claim 6** The portion on the side of the entrance / exits including the entrance / exits in the management target area has a shape extending in a first direction towards which the transmission / reception surface of the antenna faces. The antenna is provided so as to irradiate radio waves from one end to the other end of the portion in the first direction. The entrance / exit is provided at one end of the portion so that the management target object enters and exits the management target area from a second direction intersecting the first direction. The entrance / exit detection device according to claim 1 or 4. **Claim 7** The management target area is the passenger compartment of a bus vehicle operated for the purpose of sending and receiving children going to or from a kindergarten or nursery school. The management target object is the child. The entrance / exit detection device according to claim 1 or 4.

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