JP2008197823A - Smart plate and smart plate communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a SMART plate and a SMART plate communication system that can notify a driver of a low battery level of the SMART plate without requiring the installation of roadside units in places where the vehicle drops in periodically. <P>SOLUTION: The SMART plate 10 comprises an active circuit part and a passive circuit part. A passive communication area Pas is set in an active communication area Act for service reception from the system to reconcile active communication and passive communication. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a smart plate (electronic license plate) and a smart plate communication system.

  Conventionally, for example, as described in Patent Document 1 and Patent Document 2, a smart plate storing information on a license plate of a vehicle is attached to the license plate of the vehicle, and the stored license plate information is wirelessly communicated to a roadside device. Smart plate communication systems have been proposed.

The smart plate used in this smart plate communication system generally employs DSRC (Dedicated Short Range Communication) communication, which is an active method that operates by receiving power supply from a built-in battery. ", You will not be able to receive services from the system. Therefore, it is necessary to notify the driver that the remaining battery level has decreased and to quickly replace the battery.
JP 2004-240551 A JP 2005-67459 A

  As a method of detecting the low battery level and notifying the driver, the contents of communication when a roadside machine is installed in a place where the vehicle regularly stops (for example, a gas station or a service station) and communicates with the roadside machine. It is conceivable to determine whether or not the remaining battery level has decreased from the content of the communication and notify the driver. However, this method has many problems such as installation cost because it is necessary to install a roadside machine at a place where vehicles regularly stop.

  The present invention has been made in view of the above problems, and a smart plate and a smart that can inform the driver of a decrease in the remaining battery level of the smart plate without installing a roadside device where the vehicle regularly stops. An object is to provide a plate communication system.

To achieve the above object, the smart plate according to claim 1 is a smart plate that is attached to a vehicle and performs DSRC communication with a roadside device installed on the roadside.
An active circuit unit for performing communication by an active method;
And a passive circuit unit that performs communication by a passive method.

  As described above, the smart plate according to the present invention includes an active circuit unit that performs communication by an active method and a passive circuit unit that performs communication by a passive method that can communicate without using a battery, thereby receiving power supply from the battery. Even when the active circuit unit that operates does not operate due to battery exhaustion, the passive circuit unit enables communication with the roadside machine.

  As a result, if the roadside machine cannot communicate with the smart plate using the active method, and if the passive method can be used, the remaining battery capacity of the smart plate is reduced. Since the determination can be made, it is possible to notify the driver of a decrease in the remaining battery level.

As described in claim 2, the active circuit unit operates by receiving power supply from a battery built in the smart plate,
The passive circuit unit is operated by a current generated by receiving a radio wave transmitted from a roadside machine.

  As a result, even when the active circuit unit becomes inoperable due to battery exhaustion, the passive circuit unit can operate by receiving a radio wave from the roadside device and generating a current by electromagnetic induction or antenna resonance.

  According to a third aspect of the present invention, the passive circuit unit transmits less information to the roadside device than information transmitted from the active circuit unit to the roadside device. This is because the active circuit unit communicates a large amount of information with the roadside device in order to receive services by the smart plate communication system, but the passive circuit unit operates with low power and handles a small amount of information.

According to the description of claim 4, in the smart plate communication system that performs DSRC communication between the smart plate attached to the vehicle and the roadside machine installed on the roadside,
The roadside machine communicates with both the active and passive systems. When a vehicle equipped with a smart plate travels, the active system communicates with the smart plate before the passive system. In order to start communication, an active communication area that performs active communication and a passive communication area that performs passive communication are provided on a road on which the vehicle travels.

  Thereby, in the roadside machine, it is possible to start communication using the active method with the smart plate first, and when the communication is not established, communication using the passive method can be started. When communication with the smart plate is established by communication using the passive method, it is possible to determine that the remaining battery level in the smart plate is low and notify the driver to that effect. It becomes.

  As described above, in the present invention, it is only necessary to start communication between the active plate and the smart plate prior to communication using the passive method. Therefore, as described in claim 5, even if the roadside unit is provided so that part or all of the passive communication area is included in the active communication area, the same effect can be obtained.

  According to a sixth aspect of the present invention, the roadside unit may be provided with a passive communication area adjacent to an active communication area in front of a traveling direction in which a vehicle equipped with a smart plate travels. Similar effects can be achieved.

  A smart plate communication system according to a seventh aspect includes the smart plate according to the first to third aspects, and the roadside device performs DSRC communication with the smart plate. Accordingly, the roadside device can perform communication with different communication methods between the active plate and the smart plate capable of performing the communication using the passive method without battery.

  Hereinafter, embodiments of a smart plate and a smart plate communication system of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a smart plate communication system. The smart plate communication system is mainly configured by a smart plate 10 as a radio wave module attached to a license plate or the like of a vehicle, a roadside device 20, and a center 30.

  The smart plate communication system is an active method for storing vehicle information such as a vehicle registration number and a model number in the smart plate 10 and connecting to the center 30 and the roadside device 20 installed on the road. This is a system for performing wireless communication by DSRC communication (method) and recognizing the vehicle (for example, whether or not it is a service subscriber) by transmitting vehicle information of the vehicle.

  FIG. 2 shows a circuit configuration of the smart plate 10. As shown in FIG. 2, the smart plate 10 according to this embodiment includes an active circuit unit and a passive circuit unit. The active circuit unit includes a Wake-Up unit 101, a Wake-Up control unit 102, a DSRC communication unit 103, a nonvolatile memory 104, a battery 105, and a power supply unit 106.

  The active circuit unit maintains a sleep state except when communication with the roadside device 20 is performed in order to suppress power consumption of the battery 105. When the smart plate 10 enters the service area, that is, the DSRC communication area (hereinafter referred to as the active communication area Act) based on the active method of the roadside machine 20, the Wake-Up unit 101 detects the received radio wave as an envelope, When the pattern matches the pattern of the DSRC communication method, the DSRC communication unit 103 is activated assuming that the smart plate 10 has entered the active communication area Act of the roadside device 20. The DSRC communication unit 103 activated thereby starts communication with the roadside device 20.

  The DSRC communication unit 103 reads out vehicle information (various information such as a vehicle registration number and a model number) stored in the nonvolatile memory 104 adopting a nonvolatile storage medium such as an EEPROM and transmits the vehicle information to the roadside device 20. For example, if the vehicle registration number obtained through the roadside machine 20 is a subscriber, the center 30 provides a service to the vehicle.

  Here, the smart plate 10 is assumed to be replaced for each vehicle inspection, and is equipped with a battery 105 having a capacity that guarantees the number of communications within the vehicle inspection period. Therefore, if the number of communications with the roadside machine 20 within the vehicle inspection period is less than the number of communications initially assumed, the active circuit unit is activated by power supply from the battery 105.

  However, if the remaining number of the battery 105 is exhausted (becomes zero) because the number of communications within the vehicle inspection period exceeds the initially assumed number of communications, the active circuit unit becomes inoperable and the smart plate communication Service by the system cannot be received. For this reason, it is necessary to notify the driver that the remaining amount of the battery 105 has decreased (has been lost) and to quickly replace the battery.

  Therefore, in the present embodiment, as shown in FIG. 2, the smart plate 10 includes an antenna circuit unit 111 and a logic circuit unit 112, and includes a passive circuit unit that operates without receiving power supply from the battery 105. As shown in FIG. 3, when the smart plate 10 enters the passive DSRC communication area (hereinafter referred to as passive communication area Pas) set in the active communication area Act, the passive circuit unit A current is generated by receiving a radio wave received from the roadside machine 20, and the logic circuit unit 112 is operated by the current.

  The antenna circuit unit 111 employs a radio wave system that generates a current using radio waves from the roadside unit 20 by using antenna resonance. In addition, for example, the antenna circuit unit 111 uses electromagnetic induction from the roadside unit 20. You may employ | adopt the electromagnetic induction system which generate | occur | produces an electric current with an electromagnetic wave. Even when the active circuit unit becomes inoperable due to the battery 105 running out of battery, the antenna circuit unit 111 receives a radio wave from the roadside unit 20 and generates a current by resonance of the antenna or electromagnetic induction. Can be operated.

  The logic circuit unit 112 transmits only a vehicle registration number to the roadside device 20 among information of a small amount of information that can be communicated in a passive manner, for example, vehicle information stored in the nonvolatile memory 104. In other words, the active circuit unit communicates a large amount of information with the roadside device in order to receive services by the smart plate communication system, but the passive circuit unit operates with low power and handles a small amount of information. Therefore, the passive circuit unit transmits less information to the roadside device than information transmitted from the active circuit unit to the roadside device 20.

  As described above, the smart plate 10 according to the present embodiment includes the active circuit unit that performs communication by the active method and the passive circuit unit that performs communication by the passive method that can communicate without using the battery. Even when the active circuit unit that operates upon receipt of the supply stops operating due to battery exhaustion, the passive circuit unit enables communication with the roadside unit 20.

  Thereby, in the roadside device 20, when communication with the smart plate 10 can be performed with the smart plate 10, the communication with the active method is performed from the information acquired by the communication, even though the subscriber is a subscriber. Since it can be determined that the battery level of the smart plate 10 has decreased, it is possible to notify the driver of a decrease in the battery level. As shown in FIG. 3, the driver sees the external display 21 on which the notification is displayed, and promptly performs a reissue procedure of the smart plate 10 at a car dealer or an inspection place.

  FIG. 3 shows an example when the passive communication area Pas by the roadside machine 20b is set in the active communication area Act set by the roadside machine 20a constituting the roadside machine 20. The active communication area Act has a communication range of about 5 m in diameter, while the passive communication area Pas has a communication range of about 2 m in diameter.

  The roadside machine 20 of the present embodiment is configured by the roadside machines 20a and 20b, so that DSRC communication by both active and passive methods is possible. However, the active communication area Act and the passive communication area Pas are different from each other. The set positional relationship is set such that when the vehicle travels, the vehicle enters the active communication area Act before the passive communication area Pas. In other words, the active communication area Act and the passive communication area Pas are provided on the road so that communication using the active method starts communication with the smart plate 10 prior to communication using the passive method.

  Thereby, the roadside device 20a starts communication with the smart plate 10 using the active method before communication using the passive method. When the communication is not established, the roadside device 20b starts the communication by the passive method. When the communication with the smart plate 10 is established by the communication by the passive method, the roadside device 20b is built in the smart plate 10. It can be determined that the remaining amount of the battery 105 is low, and that can be notified to the driver.

  As described above, since it is only necessary to start active communication with the smart plate 10 prior to communication using the passive method, the entire passive communication area Pas is active communication as shown in FIG. It may be set so as to be included in the area Act, or may be set so that a part of the passive communication area Pas is included in the active communication area Act. Also, as shown in FIG. 4, a passive communication area Pas may be set adjacent to the active communication area Act in front of the vehicle traveling direction.

  The center 30 receives the vehicle information acquired from the roadside machine 20a, determines whether to provide the service, and provides the service when it is determined to provide the service. In addition, when a small amount of information such as a vehicle registration number is acquired from the roadside machine 20b, a process for displaying an alarm indicating that the remaining battery level is low is executed on the external display 21 shown in FIGS. . In addition, in the center 30, you may make it display a vehicle registration number with the battery remaining charge falling. This makes it easier for the driver of the vehicle to determine whether or not the vehicle with the remaining battery level is the host vehicle.

  Next, the operation of the active circuit section of the smart plate 10 will be described using the flowchart shown in FIG. When the vehicle to which the smart plate 10 is attached enters the communication area of the roadside machine 20, the radio wave from the roadside machine 20 is received in step S11 of FIG. 5, and the received signal is envelope-detected in step S12.

  In step S13, it is determined whether the pattern matches the pattern of the DSRC communication method as a result of detection. If the determination is affirmative, the process proceeds to step S14. If the determination is negative, the process ends. In step S14, the DSRC communication unit 103 is activated assuming that the smart plate 10 has entered the active communication area Act of the roadside device 20a, and vehicle information is transmitted to the roadside device 20a in step S15.

  FIG. 6 is a flowchart showing the operation of the passive circuit unit of the smart plate 10. The passive circuit unit operates by receiving a radio wave transmitted from the roadside machine 20b when communication by the active method is not established between the smart plate 10 and the roadside machine 20a. In step S21 of FIG. 6, a current is generated by electromagnetic induction by receiving a radio wave transmitted from the roadside machine 20b. In step S22, the vehicle registration number is read from the nonvolatile memory 104. In step S23, the read vehicle registration number is read. Is transmitted to the roadside machine 20b.

  Next, operations of the roadside devices 20a and 20b and the center 30 will be described with reference to the flowchart shown in FIG. In step S31 of FIG. 7, the roadside device 20a starts communication with the smart plate 10 by the active method. In step S32, it is determined whether communication has been established. If the determination is affirmative, the process proceeds to step S33. If the determination is negative, the process proceeds to step S37.

  In the center 30, vehicle information is received from the roadside machine 20a in step S33, and it is determined whether or not it is a subscriber registered in advance in step S34. If an affirmative determination is made, service provision is started in step S35. If a negative determination is made, the external display 21 indicates that the user is a non-subscriber who cannot receive the service provision.

  In step S37, since communication using the active method has not been established, the roadside device 20b starts communication with the smart plate 10 using the passive method. In step S38, it is determined whether communication has been established. Here, when an affirmative determination is made, the center 30 causes the external display 21 to display a display indicating that the remaining battery level of the smart plate 10 has decreased (has been lost) in step S39. On the other hand, if a negative determination is made, it is determined that the vehicle is not attached with the smart plate 10, and the present process is terminated.

  As described above, the smart plate communication system of the present embodiment includes the active circuit unit and the passive circuit unit in the smart plate 10, and sets the passive communication area Pas in the active communication area Act for receiving the service of the system. By doing so, it is configured to achieve both active communication and passive communication. Thereby, it is possible to notify the driver of a decrease in the remaining battery level of the smart plate 10 without installing a roadside device at a place where the vehicle regularly stops.

It is a figure for demonstrating a smart plate communication system. 2 is a block diagram showing a circuit configuration of a smart plate 10. FIG. It is a figure at the time of providing the passive system communication area Pas in the active system communication area Act. It is a figure at the time of providing the passive system communication area Pas adjacent to the active system communication area Act. 4 is a flowchart for explaining an operation of an active circuit of the smart plate 10. 4 is a flowchart for explaining an operation of a passive circuit unit of the smart plate 10. It is a flowchart for demonstrating operation | movement of the roadside machines 20a and 20b and the center 30. FIG.

Explanation of symbols

10 ... Smart plate 20 ... Roadside machine 30 ... Center
Act ・ ・ ・ Active method area
Pas ・ ・ ・ Passive communication area

Claims (7)

In the smart plate that is attached to the vehicle and performs DSRC communication with the roadside machine installed on the roadside,
An active circuit unit for performing communication by an active method;
A smart plate comprising: a passive circuit unit that performs communication by a passive method. The active circuit unit operates by receiving power supply from a battery built in the smart plate,
The smart plate according to claim 1, wherein the passive circuit unit is operated by a current generated by receiving a radio wave transmitted from the roadside device.   3. The smart plate according to claim 1, wherein the passive circuit unit transmits less information to the roadside device than information transmitted from the active circuit unit to the roadside device. 4. In a smart plate communication system that performs DSRC communication between a smart plate attached to a vehicle and a roadside machine installed on the roadside,
The roadside machine performs communication by both an active method and a passive method, and when a vehicle equipped with the smart plate travels, the communication by the active method is performed before the communication by the passive method. An active communication area that performs communication by the active method and a passive communication area that performs communication by the passive method are provided on a road on which the vehicle travels so as to start communication with a plate. Smart plate communication system.   5. The smart plate communication system according to claim 4, wherein the roadside unit is provided so that a part or all of the passive communication area is included in the active communication area.   5. The smart according to claim 4, wherein the roadside unit is provided with the passive communication area adjacent to a front of a traveling direction in which a vehicle on which the smart plate is mounted travels with respect to the active communication area. Plate communication system. A smart plate according to claims 1 to 3,
The smart plate communication system according to any one of claims 4 to 6, wherein the roadside device performs DSRC communication with the smart plate.

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