WO2019176510A1

WO2019176510A1 - In-vehicle communication device, in-vehicle communication system, communication program, and communication method

Info

Publication number: WO2019176510A1
Application number: PCT/JP2019/006937
Authority: WO
Inventors: 誠佐分利
Original assignee: 株式会社オートネットワーク技術研究所; 住友電装株式会社; 住友電気工業株式会社
Priority date: 2018-03-15
Filing date: 2019-02-25
Publication date: 2019-09-19
Also published as: JP2019156280A

Abstract

The present invention provides an in-vehicle communication device, an in-vehicle communication system, a communication program, and a communication method that can be expected to reduce the time required for communication between a communication device provided in a vehicle body and a plurality of communication devices provided in a plurality of wheels. An in-vehicle communication device according to the present embodiment is provided with: a request-signal transmission unit that wirelessly and sequentially transmits, from each of a plurality of transmission antennas, a request signal including identification information that is different for each of the transmission antennas; and a response-signal reception unit that receives, by using a reception antenna, a response signal transmitted by a wheel-side communication device that received the request signal transmitted by the request-signal transmission unit, the response signal including the identification information included in the request signal. After finishing the transmission of a request signal from a first transmission antenna, the request-signal transmission unit starts the transmission of a request signal from a second transmission antenna without waiting for the reception, from a wheel-side communication device, of a response signal for the request signal from the first transmission antenna.

Description

In-vehicle communication device, in-vehicle communication system, communication program, and communication method

The present invention relates to an in-vehicle communication device, an in-vehicle communication system, a communication program, and a communication method in which a communication device provided in a vehicle body and a plurality of communication devices provided in each wheel of the vehicle perform wireless communication.

There is a tire pressure monitoring system (TPMS: Tire Pressure Monitoring System) that detects the air pressure of the tires installed in the vehicle and issues a warning to the user if the detected air pressure is abnormal. In the tire pressure monitoring system, the monitoring unit provided on the vehicle body transmits a request signal using radio waves in the LF (Low Frequency) band, and the sensor unit provided on the wheel detects the tire pressure in response to receiving the request signal. A response signal including the detection result is transmitted using radio waves in an RF (Radio Frequency) band or an UHF (Ultra High Frequency) band. The monitoring unit receives a response signal from each sensor unit and monitors the air pressure of each tire of the vehicle.

In Patent Document 1, a transmission coil antenna is provided in the vicinity of each tire, and a request signal is transmitted from the transmission coil antenna only to the corresponding sensor unit using a magnetic field as a medium, so that each sensor unit is mounted. There has been proposed a tire pressure monitoring system that can determine the position of a tire on which each sensor unit is mounted even if the ID code of each sensor unit is not registered in association with the tire position.

JP 2004-161245 A

In the tire pressure monitoring system, for example, if the vehicle is configured to include four tires, the monitoring unit needs to transmit a request signal and receive a response signal with the four sensor units. The monitoring unit cannot communicate with the four sensor units simultaneously, but communicates with the four sensor units in order. For this reason, it takes a long time for the monitoring unit to finish communication with the four sensor units. The longer the communication time is, for example, in the case of a configuration in which communication is performed when the engine of the vehicle is started, the driver may start running the vehicle before the communication ends, and there is a possibility that a warning regarding tire air pressure will not be in time.

The present invention has been made in view of such circumstances, and an object thereof is communication between a communication device provided on a vehicle body and a plurality of communication devices provided on a plurality of wheels. An object is to provide an in-vehicle communication device, an in-vehicle communication system, a communication program, and a communication method that can be expected to reduce the time required.

The in-vehicle communication device according to this aspect uses the plurality of transmitting antennas provided on the vehicle body of the vehicle in association with the plurality of wheels of the vehicle, and the plurality of receiving antennas provided on the vehicle body. In a vehicle-mounted communication device that performs wireless communication with a plurality of wheel-side communication devices respectively provided on wheels, request signals including identification information that differs for each transmission antenna are sequentially transmitted from the plurality of transmission antennas. A request signal transmitter for wireless transmission, and a response signal transmitted by the wheel side communication device that has received the request signal transmitted by the request signal transmitter, including identification information included in the request signal, as the reception antenna A response signal receiving unit that receives the request signal, and the request signal transmitting unit responds to the request signal after finishing transmitting the request signal from the first transmitting antenna. Without waiting for reception of response signals from the wheel-side communication device, it starts transmission of the request signal from the second of the transmitting antenna.

The in-vehicle communication system according to this aspect includes a plurality of wheel-side communication devices respectively provided on a plurality of wheels of a vehicle, a plurality of transmitting antennas provided on the vehicle body of the vehicle in association with the wheels, and A vehicle body side communication device that performs wireless communication with the wheel side communication device using a receiving antenna provided on the vehicle body, and the vehicle body side communication device has identification information that is different for each transmission antenna. A request signal transmission unit that wirelessly transmits a request signal including the plurality of transmission antennas in order, and a response signal from the wheel-side communication device with respect to the request signal transmitted by the request signal transmission unit, the reception antenna A response signal receiving unit that receives the request signal, and the wheel side communication device receives the request signal from the vehicle body side communication device, and the request signal reception unit receives the request signal. An identification information acquisition unit that acquires identification information included in the received request signal, and a response signal transmission unit that wirelessly transmits a response signal including the identification information acquired by the identification information acquisition unit. The request signal transmitter, after finishing the transmission of the request signal from the first transmitting antenna, without waiting for the response signal from the wheel side communication device to receive the request signal, the second Transmission of the request signal from the transmitting antenna is started.

The communication program according to this aspect uses the plurality of transmission antennas provided on the vehicle body of the vehicle in association with the plurality of wheels of the vehicle in an in-vehicle communication device mounted on the vehicle, and the transmission antenna. A request signal including different identification information for each of the plurality of transmitting antennas is wirelessly transmitted sequentially from the plurality of transmitting antennas, and the request signal is received when a plurality of wheel side communication devices respectively provided on the plurality of wheels receive the request signal. When a response signal to be transmitted including identification information included in the signal is received using a receiving antenna provided on the vehicle body, and when request signals are transmitted in order from the plurality of transmitting antennas by radio In addition, after finishing the transmission of the request signal from the first transmitting antenna, without waiting for reception of a response signal from the wheel side communication device to the request signal, Wherein to initiate transmission of the request signal from the transmitting antenna.

In the communication method according to this aspect, a plurality of wheel side communication devices respectively provided on a plurality of wheels of a vehicle and a vehicle body side communication device mounted on a vehicle body of the vehicle are associated with the wheels, respectively. In the communication method of performing wireless communication using a plurality of transmitting antennas provided on the vehicle body and a receiving antenna provided on the vehicle body, the vehicle body side communication device includes different identification information for each transmitting antenna. Request signals are wirelessly transmitted in order from the plurality of transmitting antennas, the wheel side communication device receives the request signal from the vehicle body side communication device, and acquires identification information included in the received request signal, A response signal including the acquired identification information is wirelessly transmitted, and the vehicle body side communication device receives the response signal from the wheel side communication device using the reception antenna, and the vehicle body side When the transmission device wirelessly transmits the request signal from the plurality of transmission antennas in order, after the transmission of the request signal from the first transmission antenna, the wheel side communication device for the request signal The transmission of the request signal from the second transmitting antenna is started without waiting for reception of the response signal.

The present application can be realized not only as an in-vehicle communication device including such a characteristic processing unit, but also as a communication method using such characteristic processing as a step, or causing a computer to execute such a step. Can be realized as a communication program. Further, it can be realized as a semiconductor integrated circuit that realizes part or all of the in-vehicle communication device, or can be realized as another device or system including the in-vehicle communication device.

According to the above, it can be expected that the time required for communication between the communication device provided on the vehicle body and the plurality of communication devices provided on the plurality of wheels is reduced.

It is a schematic diagram which shows the structure of the vehicle-mounted communication system which concerns on this Embodiment. It is a block diagram which shows the structure of the monitoring apparatus which concerns on this Embodiment. It is a schematic diagram which shows an example of sensor position information. It is a block diagram which shows the structure of the sensor apparatus which concerns on this Embodiment. It is a schematic diagram for demonstrating the procedure of the radio | wireless communication between a monitoring apparatus and four sensor apparatuses. It is a schematic diagram for demonstrating the time concerning communication of a monitoring apparatus and a sensor apparatus. It is a flowchart which shows the procedure of the request signal transmission process which the monitoring apparatus which concerns on this Embodiment performs. It is a flowchart which shows the procedure of the response signal transmission process which the sensor apparatus which concerns on this Embodiment performs. It is a flowchart which shows the procedure of the response signal reception process which the monitoring apparatus which concerns on this Embodiment performs. It is a flowchart which shows the procedure of the response signal reception process which the monitoring apparatus which concerns on this Embodiment performs. It is a flowchart which shows the procedure of the transmission process of the period notification signal which the sensor apparatus which concerns on this Embodiment performs. It is a flowchart which shows the procedure of the reception process of the period notification signal which the monitoring apparatus which concerns on this Embodiment performs.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described. Moreover, you may combine arbitrarily at least one part of embodiment described below.

(1) The in-vehicle communication device according to this aspect uses a plurality of transmitting antennas provided on a vehicle body of the vehicle in association with a plurality of wheels of the vehicle, and a receiving antenna provided on the vehicle body. In the in-vehicle communication device that performs wireless communication with the plurality of wheel-side communication devices respectively provided on the plurality of wheels, a request signal including identification information that differs for each transmission antenna is transmitted to the plurality of transmission antennas. A request signal transmitter that wirelessly transmits in order, and a response signal that the wheel side communication device that has received the request signal transmitted by the request signal transmitter includes the identification information included in the request signal, A response signal receiving unit that receives using a receiving antenna, and the request signal transmitting unit transmits the request signal from the first transmitting antenna to the request signal. Without waiting for reception of response signals from the wheel-side communication device which starts transmission of the request signal from the second of the transmitting antenna.

In this aspect, the vehicle body side communication device is provided on the vehicle body of the vehicle, and the wheel side communication device is provided on each of the plurality of wheels of the vehicle. The vehicle body is provided with a plurality of transmission antennas in association with a plurality of wheels, and the vehicle body side communication device transmits a radio signal from each transmission antenna to the corresponding wheel side communication device. The vehicle body is provided with a common reception antenna for the plurality of wheel side communication devices, and the vehicle body side communication device receives a radio signal from the wheel side communication device using the reception antenna.
The vehicle body side communication device wirelessly transmits a request signal including different identification information for each transmitting antenna in order from a plurality of transmitting antennas. The wheel side communication device that has received this request signal acquires the identification information included in the received request signal, and transmits a response signal including the acquired identification information. The vehicle body side communication device that has received the response signal at the receiving antenna can determine which of the transmitting antennas is the response signal based on the identification information included in the response signal. .
In addition, when the vehicle body side communication device wirelessly transmits the request signal from the plurality of transmission antennas in order, after the transmission of the request signal from one transmission antenna, the vehicle side communication device receives the request signal from the wheel side communication device. Transmission of a request signal from the next transmitting antenna is started without waiting for reception of a response signal. As a result, the vehicle body side communication device completes the process of transmitting the request signals in order from the plurality of transmitting antennas in a short time compared to the case where the next request signal is transmitted after waiting for the response signal to be received. can do. When request signals are transmitted in order without waiting for reception of response signals, the order of response signals transmitted from a plurality of wheel side communication devices may vary. By including the identification information in the signal, it is possible to determine which of the wheel side communication devices is the response signal even if the order of reception varies.

(2) It is preferable that the request signal transmission unit sequentially transmits the request signal from the plurality of transmission antennas.

In this aspect, the vehicle body side communication device transmits request signals to the plurality of wheel side communication devices sequentially from the plurality of transmission antennas. Thereby, the time required for transmitting the request signal a plurality of times can be shortened.

(3) It is preferable to provide the determination part which determines the said wheel side communication apparatus of the transmission source of the said response signal based on the identification information contained in the response signal which the said response signal receiving part received.

In this aspect, the vehicle body side communication device determines which wheel side communication device that is the transmission source of this response signal is based on the identification information included in the response signal received by the receiving antenna. To do. The vehicle body side communication device stores the correspondence between the identification information and the position of each transmitting antenna, for example, so that the transmission side wheel side communication device is based on the identification information included in the received response signal. It can be determined which wheel is provided.

(4) The request signal transmission unit, after finishing the transmission of the request signal from the first transmitting antenna, during a time shorter than the transmission time of the response signal transmitted by the wheel side communication device, It is preferable that transmission of the request signal from the second transmitting antenna is started.

In this aspect, after the vehicle body side communication device finishes transmitting the request signal from one transmitting antenna, the vehicle body side communication device transmits the next transmission during a time shorter than the transmission time of the response signal transmitted by the wheel side communication device. The transmission of the request signal from the trusted antenna is started. Thereby, the time required for wireless communication between the vehicle body side communication device and the plurality of wheel side communication devices can be more reliably reduced.

(5) The in-vehicle communication system according to this aspect includes a plurality of wheel-side communication devices respectively provided on a plurality of wheels of a vehicle, and a plurality of transmission antennas provided on the vehicle body of the vehicle in association with the wheels. And a vehicle body side communication device that performs wireless communication with the wheel side communication device using a reception antenna provided on the vehicle body, and the vehicle body side communication device is different for each transmission antenna. A request signal transmitting unit that wirelessly transmits a request signal including identification information in order from the plurality of transmitting antennas, and a response signal from the wheel side communication device for the request signal transmitted by the request signal transmitting unit. A response signal receiving unit that receives a response signal using an antenna for the vehicle, wherein the wheel side communication device includes a request signal receiving unit that receives a request signal from the vehicle body side communication device, and the request signal receiving unit includes: An identification information acquisition unit that acquires identification information included in the received request signal; and a response signal transmission unit that wirelessly transmits a response signal including the identification information acquired by the identification information acquisition unit, and the vehicle body side communication device The request signal transmission unit of the second, after finishing the transmission of the request signal from the first antenna for transmission, without waiting for reception of a response signal from the wheel side communication device to the request signal, the second Transmission of the request signal from the transmitting antenna is started.

In this aspect, similarly to aspect (1), the process in which the vehicle body side communication device sequentially transmits request signals from the plurality of transmission antennas to the wheel side communication device can be completed in a short time.

(6) It is preferable that the said response signal transmission part of the said wheel side communication apparatus transmits the said response signal in multiple times over a random time.

In this aspect, the wheel side communication device transmits a response signal multiple times at random intervals. Thereby, for example, even when transmission of response signals by a plurality of wheel side communication devices overlaps, transmission of subsequent response signals is performed at different timings, so that the vehicle body side communication device is transmitted from the plurality of wheel side communication devices. This increases the possibility of receiving the response signal.

(7) The response signal transmission unit of the wheel side communication device transmits a response signal including second identification information attached to the wheel side communication device, and the vehicle body side communication device includes the response signal reception unit. It is preferable to have a determination unit that determines the wheel-side communication device that is the transmission source of the response signal based on the identification information and the second identification information included in the received response signal.

In this aspect, the wheel side communication device transmits the response signal including the second identification information attached to itself together with the identification information included in the request signal. The vehicle body side communication device determines the wheel side communication device that is the transmission source of the response signal based on the identification information and the second identification information included in the response signal from the wheel side communication device. The vehicle body side communication device stores, for example, the correspondence between the identification information and the second identification information and the position of each transmitting antenna, and based on the identification information included in the received response signal, It can be determined which wheel of the vehicle the communication device is provided on.

(8) A communication program according to this aspect uses a plurality of transmission antennas provided on a vehicle body of the vehicle in association with a plurality of wheels of the vehicle, in an in-vehicle communication device mounted on the vehicle, When request signals including different identification information for each transmission antenna are wirelessly transmitted in order from the plurality of transmission antennas, and a plurality of wheel side communication devices respectively provided on the plurality of wheels receive the request signal To receive a response signal including identification information included in the request signal using a receiving antenna provided on the vehicle body, and wirelessly transmit the request signals from the plurality of transmitting antennas in order. When transmitting, after finishing transmission of the request signal from the first transmitting antenna, without waiting for reception of a response signal from the wheel side communication device to the request signal To start transmission of the request signal from the second of the transmitting antenna.

(9) In the communication method according to this aspect, a plurality of wheel side communication devices respectively provided on a plurality of wheels of a vehicle and a vehicle body side communication device mounted on the vehicle body of the vehicle are associated with the wheels, respectively. In the communication method for performing wireless communication using a plurality of transmission antennas provided on the vehicle body and a reception antenna provided on the vehicle body, the vehicle body side communication device is identified differently for each transmission antenna. A request signal including information is wirelessly transmitted sequentially from the plurality of transmitting antennas, the wheel side communication device receives the request signal from the vehicle body side communication device, and identification information included in the received request signal And wirelessly transmitting a response signal including the acquired identification information, and the vehicle body side communication device receives the response signal from the wheel side communication device using the reception antenna, and the vehicle When the side communication device wirelessly transmits the request signal from the plurality of transmission antennas in order, after the transmission of the request signal from the first transmission antenna is completed, the wheel side communication device for the request signal The transmission of the request signal from the second transmitting antenna is started without waiting for reception of a response signal from.

[Details of the embodiment of the present invention]
A specific example of the in-vehicle communication system according to the embodiment of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to a claim are included.

<System overview>
FIG. 1 is a schematic diagram showing a configuration of an in-vehicle communication system according to the present embodiment. The in-vehicle communication system 100 according to the present embodiment is also a tire air pressure monitoring system that detects the tire air pressure of the four wheels 3 provided in the vehicle 1 and notifies the driver of information such as the presence or absence of the above. The in-vehicle communication system 100 according to the present embodiment includes a monitoring device 10 provided at an appropriate position of the vehicle body of the vehicle 1, four sensor devices 30 provided in portions such as tires or wheels of each wheel 3, and the vehicle 1. For example, a notification device 8 provided near the driver's seat is provided. Each sensor device 30 detects the air pressure of the tire of the wheel 3 provided with the device itself. The in-vehicle communication system 100 according to the present embodiment acquires information related to the tire air pressure of each wheel 3 by the monitoring device 10 performing wireless communication with each sensor device 30, and the notification device 8 based on the acquired information. The tire pressure is notified using.

The vehicle 1 is equipped with four transmission antennas 5 for the monitoring device 10 to transmit LF band radio signals to the four sensor devices 30. Since the vehicle 1 according to the present embodiment is provided with wheels 3 on the right front, right rear, left front, and left rear, and each wheel 3 is provided with a sensor device 30, four transmission antennas 5 are associated with each wheel 3. The vehicle 1 is provided at the front right, rear right, front left and rear left. Each transmission antenna 5 is mounted on, for example, each tire house of the vehicle 1 or its periphery. The mounting position of each transmission antenna 5 is preferably a position where the sensor device 30 of each wheel 3 can receive a radio signal transmitted from each transmission antenna 5 exceptionally. The signal reachable range is set so that the LF band radio signal transmitted from each transmission antenna 5 is received only by one corresponding sensor device 30 and not received by the other three sensor devices 30. However, there is a possibility that a plurality of sensor devices 30 receive radio signals transmitted from the transmission antennas 5 due to the influence of the surrounding environment of the vehicle 1 and the like.

The monitoring device 10 is connected to four transmission antennas 5 provided at four locations of the vehicle 1 via individual signal lines. The monitoring device 10 selects one of the transmission antennas 5 and performs a process of transmitting a wireless signal to the one sensor device 30 in order for the four transmission antennas 5, thereby performing wireless signals for the four sensor devices 30. Send. The monitoring device 10 transmits a request signal for requesting transmission of the tire air pressure detection result to each sensor device 30 as a radio signal in the LF band. In the in-vehicle communication system 100 according to the present embodiment, identification information is attached to each transmission antenna 5, and the request signal transmitted from the transmission antenna 5 includes the identification information attached to the transmission antenna 5. It is. Hereinafter, the identification information given to the transmission antenna 5 is referred to as an antenna ID.

When the sensor device 30 receives a request signal transmitted as a radio signal in the LF band from the monitoring device 10, the sensor device 30 detects the tire air pressure of the wheel 3, and sends a response signal including information on the detected tire air pressure to the UHF band. As a wireless signal. At this time, the sensor device 30 acquires the antenna ID included in the received request signal, and includes the acquired antenna ID in the response signal. Further, individual identification information (hereinafter referred to as sensor ID) is attached to the sensor device 30, and the sensor device 30 includes its own sensor ID in the request signal. That is, the response signal transmitted from each sensor device 30 to the monitoring device 10 includes information related to tire air pressure, the antenna ID acquired from the received request signal, and its own sensor ID.

The monitoring device 10 includes a receiving antenna 6 for receiving a response signal in the UHF band transmitted from the sensor device 30. The reception antenna 6 may be built in the monitoring device 10 or may be provided separately from the monitoring device 10 and connected to the monitoring device 10 via a signal line. The monitoring device 10 receives response signals from the four sensor devices 30 with the common receiving antenna 6. The monitoring device 10 can determine from which sensor device 30 the response signal is transmitted based on the antenna ID and the sensor ID included in the received response signal. The monitoring device 10 acquires tire pressure information from the received response signal, and notifies the driver of the tire pressure using the notification device 8.

The notification device 8 can be, for example, a display device provided near the driver's seat of the vehicle 1. For example, the monitoring device 10 may display the tire air pressure detection result on the notification device 8 in real time. Further, for example, the monitoring device 10 may determine whether there is an abnormality in the tire air pressure, and may display a warning message or the like on the notification device 8 when determining that there is an abnormality. The notification device 8 may have a configuration other than the display device, for example, may have a configuration for notifying the tire air pressure by sound output, or may be, for example, a lamp that is turned on in response to an abnormality in the tire air pressure.

The sensor device 30 not only receives the request signal from the monitoring device 10, but also periodically detects the tire pressure, for example, and periodically transmits a signal including information on the detected tire pressure to the monitoring device 10. Good. In this case, the signal transmitted by the sensor device 30 includes information related to the tire pressure and its own sensor ID, and does not include the antenna ID. The monitoring device 10 that has received the periodic signal from the sensor device 30 at the reception antenna determines which sensor device 30 has transmitted this signal based on the sensor ID included in the received signal. judge.

The process in which the monitoring device 10 transmits the request signal and receives the response signal from the sensor device 30 is performed, for example, when the ignition switch of the vehicle 1 is switched from the off state to the on state or at a specific timing such as when the engine is started. Done. This process is performed for the purpose of confirming the correspondence between the transmission antenna 5 and the sensor device 30 and acquiring the tire air pressure of the wheel 3 of the vehicle 1. Thereafter, unless there are special circumstances, the monitoring device 10 receives the signal periodically transmitted by the sensor device 30 without transmitting the request signal, and the monitoring device 10 receives the signal that is transmitted periodically. Will report. The transmission of the request signal by the monitoring device 10 can be performed, for example, at the timing when the vehicle 1 shifts from the stopped state to the traveling state, or when it is determined that the tire air pressure is abnormal. The monitoring device 10 transmits a request signal at a timing when it is preferable to confirm the position of the sensor device 30.

<Device configuration>
FIG. 2 is a block diagram illustrating a configuration of the monitoring apparatus 10 according to the present embodiment. The monitoring apparatus 10 according to the present embodiment includes a processing unit (processor) 11, a storage unit (storage) 12, a wired communication unit (transceiver) 13, a wireless transmission unit (transceiver) 14, a wireless reception unit (transceiver) 15, and the like. It is prepared for. The processing unit 11 is configured by using an arithmetic processing device such as a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit), for example, and executes various programs by executing a program 12a stored in the storage unit 12. Processing and control processing can be performed. In the present embodiment, the processing unit 11 reads and executes the program 12a stored in the storage unit 12, thereby transmitting and receiving wireless signals to and from the sensor devices 30 provided on the wheels 3 of the vehicle 1, A process of notifying the driver of the tire pressure based on a radio signal received from the sensor device 30 and a process of determining the mounting position of each sensor device 30 are performed.

The storage unit 12 is configured using a non-volatile memory element such as a flash memory or an EEPROM (Electrically-Erasable-Programmable-Read-Only-Memory). The storage unit 12 stores various programs executed by the processing unit 11 and various data necessary for the processing of the processing unit 11. In the present embodiment, the storage unit 12 stores a program 12a executed by the processing unit 11 and sensor position information 12b as data necessary for the execution of the program 12a. Note that the program 12a may be written in the storage unit 12 at the manufacturing stage of the monitoring device 10, for example, or the monitoring device 10 may acquire, for example, what is distributed by a remote server device, for example, What is recorded on the recording medium 99 such as a memory card or an optical disk may be read out by the monitoring device 10 and stored in the storage unit 12. For example, what is recorded on the recording medium 99 is read out by the writing device and monitored. You may write in ten memory | storage parts 12. The program 12a may be provided in a mode of distribution via a network, or may be provided in a mode recorded on the recording medium 99.

The sensor position information 12b stored in the storage unit 12 is information indicating which wheel 3 of the vehicle 1 the four sensor devices 30 mounted on the vehicle 1 are mounted on. FIG. 3 is a schematic diagram illustrating an example of the sensor position information 12b. In the present embodiment, the sensor position information 12b includes a mounting position of the sensor device 30, an antenna ID attached to the transmission antenna 5 provided corresponding to the mounting position, and a sensor attached to the sensor device 30. An ID is stored in association with each other. In this example, there are four types of mounting positions of the sensor device 30: right front, right rear, left front, and left rear, antenna IDs A1 to A4, and sensor IDs S1 to S4. Although the correspondence between the mounting position and the antenna ID does not change, the sensor ID may change due to the exchange of the wheels 3 or the like. The initial value of each information stored in the sensor position information 12b is written into the storage unit 12 in the manufacturing process of the vehicle 1, for example. However, the monitoring device 10 may determine the position of the sensor device 30 and set the sensor ID of the sensor position information 12b.

The wired communication unit 13 transmits and receives messages to and from various in-vehicle devices mounted on the vehicle 1 via an in-vehicle network provided in the vehicle 1. In the illustrated example, only the notification device 8 is connected to the in-vehicle network, but various other in-vehicle devices can be connected to the in-vehicle network. The wired communication unit 13 transmits and receives messages according to a communication protocol such as CAN (Controller Area Network) or Ethernet (registered trademark). The wired communication unit 13 can transmit a message by outputting the digital data given as a transmission message from the processing unit 11 as an electrical signal to a communication line constituting the in-vehicle network. The wired communication unit 13 samples and acquires the potential of the communication line constituting the in-vehicle network, and provides the digital data obtained as a result of the sampling to the processing unit 11 as a received message. The wired communication unit 13 can be configured by using an IC (Integrated Circuit) that performs communication according to a communication protocol such as CAN or Ethernet.

In the wireless transmission unit 14, four transmission antennas 5 are connected via individual signal lines. The wireless transmission unit 14 transmits an electric signal obtained by modulating the transmission data provided from the processing unit 11 to the transmission antenna 5, thereby transmitting an LF band radio signal having a frequency of 30 kHz to 300 kHz. In the present embodiment, the wireless transmission unit 14 selects any one of the four transmission antennas 5 and transmits a wireless signal from the selected transmission antenna 5. The radio transmission unit 14 can determine from which transmission antenna 5 the radio signal is transmitted according to the antenna ID included in the transmission data provided from the processing unit 11.

The reception antenna 6 is connected to the wireless reception unit 15. The radio receiving unit 15 receives a UHF band radio signal having a frequency of 300 MHz to 3 GHz transmitted by the sensor device 30 at the receiving antenna 6 and supplies the received data obtained by demodulating the received signal to the processing unit 11. .

Further, in the monitoring device 10 according to the present embodiment, the processing unit 11 reads and executes the program 12a stored in the storage unit 12, whereby the request signal transmission unit 21, the response signal reception unit 22, and the sensor position determination unit 23. And the like are realized as software functional blocks in the processing unit 11. The request signal transmission unit 21 controls the operation of the wireless transmission unit 14 to request the four sensor devices 20 mounted on the wheels 3 of the vehicle 1 to transmit the tire pressure detection results. Process to send. The request signal transmission unit 21 generates transmission data including a command for requesting a tire air pressure detection result and the antenna ID of the transmission antenna 5 used for transmission, and supplies the transmission data to the wireless transmission unit 14, thereby specifying one transmission. It is possible to cause the wireless transmission unit 14 to transmit a request signal from the antenna 5. The request signal transmission unit 21 transmits the request signals to the four sensor devices 30 in order by transmitting the request signals from the four transmission antennas 5 in order.

The response signal receiving unit 22 acquires received data corresponding to the response signal received by the wireless receiving unit 15 and performs processing for extracting and acquiring various types of information included in the acquired received data. The information included in the received data is, for example, information related to a tire air pressure detection result, information such as an antenna ID and a sensor ID. The response signal receiving unit 22 performs a process of determining whether or not the tire air pressure of each wheel 3 is within the normal range based on the acquired information. If the response signal receiving unit 22 is not within the normal range, the operation using the notification device 8 is performed. Can be notified to the person. For the normal range of the tire pressure, a threshold for determining this is stored in the storage unit 12 in advance. Further, the response signal receiving unit 22 gives the antenna ID and sensor ID acquired from the received data to the sensor position determining unit 23.

Based on the antenna ID and the sensor ID included in the response signal received from the sensor device 30, the sensor position determination unit 23 determines which wheel 3 is provided with the sensor device 30 that has transmitted this response signal. Or the process which determines the mounting position is performed. For example, when the antenna ID included in the response signal is A1 and the sensor ID is S1, the sensor position determination unit 23 determines that the transmission source of the response signal is based on the sensor position information 12b illustrated in FIG. It can be determined that the sensor device 30 is mounted on the right front wheel 3 of the vehicle 1. The sensor position determination unit 23 refers to the sensor position information 12b stored in the storage unit 12, and the combination of the antenna ID and the sensor ID included in the received response signal is any of the combinations stored in the sensor position information 12b. It is determined whether or not they match. If both combinations match, the sensor position determination unit 23 determines that the wheel 3 is not exchanged and the position of the sensor device 30 is the position stored in the sensor position information 12b. On the other hand, if the two combinations do not match, the sensor position determination unit 23 determines that the wheel 3 has been replaced, and stores the newly acquired combination of antenna ID and sensor ID in the sensor position information 12b. Thus, the sensor position information 12b is updated. The monitoring apparatus 10 may transmit the request signal again before updating the sensor position information 12b, and update the sensor position information 12b after confirming that the combination of the antenna ID and the sensor ID does not match a plurality of times. .

As described above, the monitoring device 10 according to the present embodiment sequentially transmits request signals from the four transmission antennas 5 to the four sensor devices 30. At this time, the monitoring device 10 continuously transmits the request signal four times without waiting for reception of a response signal from the sensor device 30 for each request signal. After transmitting a request signal from one transmission antenna 5, the request signal transmission unit 21 starts transmitting a request signal from the next transmission antenna 5 without delay.

Further, even when the sensor device 30 does not receive the request signal from the monitoring device 10, the sensor device 30 periodically transmits the tire air pressure detection result to the monitoring device 10. The signal periodically transmitted by the sensor device 30 includes information related to the tire air pressure detection result and the sensor ID, and does not include the antenna ID. The processing unit 11 of the monitoring device 10 that has received the periodic signal from the sensor device 30 acquires the sensor ID from the reception data obtained by demodulating the received signal, and provides the sensor ID to the sensor position determination unit 23. The sensor position determination unit 23 refers to the sensor position information 12b of the storage unit 12 based on the given sensor ID, and which position of the vehicle 1 the received signal is from the sensor device 30 mounted on. Determine. In this case, the sensor position determination unit 23 may determine the position on the assumption that the wheel 3 of the vehicle 1 has not been replaced.

FIG. 4 is a block diagram showing a configuration of the sensor device 30 according to the present embodiment. The sensor device 30 according to the present embodiment includes a control unit (processor) 31, a storage unit (storage) 32, an air pressure detection unit 33, a wireless reception unit (transceiver) 34, a wireless transmission unit (transceiver) 35, and the like. Has been. The control unit 31 is configured using, for example, a CPU or a microcomputer (microcomputer), and controls the operation of each unit of the sensor device 30. Although illustration is omitted, the sensor device 30 includes a battery, and each part of the sensor device 30 operates by electric power supplied from the battery.

The storage unit 32 is configured using a non-volatile memory element such as a mask ROM (Read Only Memory) or an EEPROM. In the present embodiment, the storage unit 32 stores a sensor ID 32 a assigned to the sensor device 30. The sensor ID of each sensor device 30 is set so as not to overlap at least for the four sensor devices 30 mounted on the vehicle 1. The sensor ID 32a of the storage unit 32 may be stored, for example, in the manufacturing process of the sensor device 30, may be stored in the manufacturing process of the vehicle 1, or may be stored in a place other than these.

The air pressure detecting unit 33 detects the air pressure of the tire by detecting, for example, a change amount corresponding to the air pressure of a diaphragm provided in the tire with a sensor. The air pressure detection unit 33 outputs an electrical signal corresponding to the tire air pressure. The control unit 31 can sample and acquire the electrical signal output from the air pressure detection unit 33, and can use the acquired value as information related to the tire pressure detection result.

The radio reception unit 34 is connected to a reception antenna 34a. The radio reception unit 34 receives the LF band radio signal transmitted from the monitoring device 10 by the reception antenna 34 a, and gives the reception data obtained by demodulating the received signal to the control unit 31. The wireless transmission unit 35 is connected to a transmission antenna 35a. The wireless transmission unit 35 transmits a UHF band wireless signal by outputting, to the transmission antenna 35a, an electric signal obtained by modulating transmission data provided from the control unit 31.

Further, the control unit 31 of the sensor device 30 according to the present embodiment is provided with functional blocks such as a request signal receiving unit 41, an identification information acquiring unit 42, a response signal transmitting unit 43, and the like. The request signal receiving unit 41 confirms whether or not a request signal is received from the monitoring device 10 by operating the wireless receiving unit 34 at a predetermined cycle. When the request signal is received by the wireless reception unit 34, the request signal reception unit 41 acquires the received data related to the request signal transmitted by the monitoring device 10 by acquiring data provided from the wireless reception unit 34. Although four sensor devices 30 are mounted on the vehicle 1, the timing for confirming whether or not the request signal is received from the monitoring device 10 is asynchronous in the four sensor devices 30, and the period for confirming whether or not the signal is received. Are the same.

The identification information acquisition unit 42 extracts and acquires the antenna ID included in the reception data acquired by the request signal reception unit 41. The response signal transmission unit 43 acquires the tire air pressure detection result by the air pressure detection unit 33 when the request signal reception unit 41 acquires the reception data related to the request signal from the monitoring device 10. The response signal transmission unit 43 generates transmission data including the acquired tire air pressure detection result, the antenna ID acquired by the identification information acquisition unit 42, and the sensor ID 32 a stored in the storage unit 32. The response signal transmission unit 43 sends the generated transmission data to the wireless transmission unit 35, thereby transmitting this transmission data to the monitoring device 10 as a response signal.

In the present embodiment, the sensor device 30 transmits a response signal three times in response to receiving a request signal once. The transmission interval of the three response signals is a random time, which is realized by using the random number generation function and the timer function of the control unit 31. The response signal transmission unit 43 transmits a first response signal, waits for a random time, transmits a second response signal, waits for a random time, and transmits a third response signal. The contents of the three response signals are the same. The two random waiting times are different. The response signal transmission unit 43 determines the standby time by the random number generation function every time the standby is required, and counts the determined standby time by the timer function.

Further, even when the sensor device 30 does not receive the request signal from the monitoring device 10, the sensor device 30 periodically transmits the tire air pressure detection result to the monitoring device 10. The control unit 31 of the sensor device 30 acquires the tire air pressure detection result by the air pressure detection unit 33 at a predetermined cycle. The control unit 31 generates transmission data including the acquired tire pressure detection result and the sensor ID 32a stored in the storage unit 32 and supplies the transmission data to the wireless transmission unit 35, whereby the periodic tire pressure for the monitoring device 10 is obtained. Notification of.

<Communication procedure>
FIG. 5 is a schematic diagram for explaining a procedure of wireless communication between the monitoring device 10 and the four sensor devices 30. FIG. 5 is a timing chart showing the transmission and reception of the request signal and the response signal, the transmission timing of the request signal from the four transmission antennas 5 is shown on the upper side, and the response by the four sensor devices 30 is shown on the lower side. The signal transmission timing is shown. For example, when the ignition switch of the vehicle 1 is switched from the off state to the on state, the monitoring device 10 transmits a request signal to the sensor device 30. The corresponding transmission antenna 5 is provided in the vehicle body of the vehicle 1 in the sensor device 30 provided in each of the four wheels 3, and the monitoring device 10 transmits the request signals in order from the four transmission antennas 5. Request signals are sequentially transmitted to the four sensor devices 30.

For example, the monitoring apparatus 10 transmits a request signal including the antenna ID of A1 from the transmission antenna 5 having the antenna ID of A1. After transmitting a request signal including the antenna ID of A1 for a predetermined time, the monitoring device 10 does not wait for reception of a response signal from the sensor device 30 in response to this request signal, that is, regardless of whether or not a response signal is received. Transmits a request signal including the antenna ID of A2 from the transmission antenna 5 of antenna ID A2. After transmitting a request signal including the antenna ID of A2 for a predetermined time, the monitoring apparatus 10 does not wait for reception of a response signal from the sensor device 30 with respect to the request signal, from the transmission antenna 5 having an antenna ID of A3. A request signal including the antenna ID of A3 is transmitted. Then, after transmitting a request signal including the antenna ID of A3 for a predetermined time, the monitoring apparatus 10 does not wait for reception of a response signal from the sensor device 30 in response to the request signal, and the monitoring apparatus 10 transmits the transmission antenna having the antenna ID of A4 5 transmits a request signal including the antenna ID of A4.

Note that there is a delay time, for example, due to the switching control of the transmission antenna 5 by the monitoring device 10 between the end of transmission of the request signal from one transmission antenna 5 and the start of transmission of the request signal from the next transmission antenna 5. obtain. However, it is preferable that the monitoring apparatus 10 continuously transmits four request signals by shortening the time from the end of transmission of one request signal to the start of transmission of the next request signal as much as possible.

The request signal transmitted from the transmitting antenna 5 with the antenna ID A1 is received by the sensor device 30 with the sensor ID S1. The sensor device 30 with the sensor ID S1 acquires the tire air pressure detection result and also acquires the antenna ID from the received request signal, the tire air pressure detection result, the antenna ID A1, and the sensor ID S1 of its own sensor ID. A response signal including is transmitted. The request signal transmitted from the transmitting antenna 5 having the antenna ID A2 is received by the sensor device 30 having the sensor ID S2. The sensor device 30 with the sensor ID S2 transmits a response signal including the tire air pressure detection result, the antenna ID A2, and the sensor ID S2 of its own. The request signal transmitted from the transmitting antenna 5 having the antenna ID A3 is received by the sensor device 30 having the sensor ID S3. The sensor device 30 having the sensor ID S3 transmits a response signal including the tire pressure detection result, the antenna ID A3, and the sensor ID S3 of the sensor ID. The request signal transmitted from the transmitting antenna 5 with the antenna ID A4 is received by the sensor device 30 with the sensor ID S4. The sensor device 30 with the sensor ID S4 transmits a response signal including the detection result of the tire pressure, the antenna ID A4, and the sensor ID S4 of its own. Each sensor device 30 transmits the response signal three times as described above, but only the first one is shown in FIG.

The reception timing of request signals and the transmission timing of response signals by the four sensor devices 30 are not synchronized and are performed at each timing. Therefore, even if the request signals are transmitted in the order of A1, A2, A3, and A4 as in the illustrated example, the response signals are not necessarily transmitted in the order of S1, S2, S3, and S4. . The response signal may be transmitted by the sensor device 30 during transmission of the corresponding request signal, or may be performed during transmission of the next request signal after transmission of the request signal is completed. In in-vehicle communication system 100 according to the present embodiment, monitoring device 10 transmits an antenna ID included in a request signal, and transmits an antenna ID included in the request signal received by sensor device 30 included in a response signal. For this reason, the monitoring device 10 can determine whether the response signal is a response to the request signal transmitted from which transmission antenna 5 regardless of the timing at which the response signal is received.

In addition, transmission of response signals by a plurality of sensor devices 30 may overlap. In the in-vehicle communication system 100 according to the present embodiment, each sensor device 30 transmits a response signal three times at random intervals. For this reason, even if any one of the transmissions of the response signal is duplicated, it can be expected that the other two transmissions of the response signal are performed without duplication.

FIG. 6 is a schematic diagram for explaining the time related to the communication between the monitoring device 10 and the sensor device 30. FIG. 6 shows a timing chart in which the horizontal axis represents time t. The upper side shows the transmission timing of the request signal by the monitoring device 10, the central portion shows the reception timing of the request signal by the sensor device 30, and the lower side. The transmission timing of the response signal by the sensor device 30 is shown in FIG. The monitoring device 10 transmits a request signal from one transmission antenna 5 over a predetermined time T1. At this time, the monitoring apparatus 10 repeatedly transmits a request signal including a command for requesting transmission of information related to tire air pressure and the antenna ID of the transmission antenna 5 used for transmission during a predetermined time T1. For example, the predetermined time T1 is set to several hundred milliseconds to several seconds.

Each sensor device 30 repeatedly receives a request signal from the monitoring device 10 by the wireless reception unit 34 at a predetermined cycle T2. That is, each sensor device 30 confirms the presence or absence of a request signal from the monitoring device 10 at a frequency of once every time the predetermined period T2 elapses. The predetermined period T2 of the reception timing by the sensor device 30 is set to substantially the same time as the predetermined time T1 when the monitoring device 10 transmits the request signal. That is, T2≈T1. Furthermore, it is preferable that the predetermined period T2 is not more than the predetermined time T1. That is, it is preferable that T2 ≦ T1.

The sensor device 30 that has received the request signal from the monitoring device 10 acquires the tire air pressure detection result, and acquires the antenna ID from the received request signal. The sensor device 30 transmits a response signal including a tire pressure detection result, an antenna ID, and its own sensor ID. At this time, the sensor device 30 transmits a response signal three times at random intervals. The predetermined time T3 for the sensor device 30 to transmit one response signal is a time sufficiently shorter than the predetermined time T1 for the monitoring device 10 to transmit the request signal. That is, T3 << T1. The predetermined time T3 for transmitting the response signal is set to, for example, several milliseconds to several tens of milliseconds. The time from the start of transmission of the first response signal to the completion of transmission of the third response signal is preferably shorter than the predetermined time T1.

It should be noted that the time from the completion of transmission of a request signal from one transmission antenna 5 by the monitoring device 10 to the start of transmission of a request signal from the next transmission antenna 5 is preferably shorter than a predetermined time T3 for transmitting a response signal.

<Flowchart>
FIG. 7 is a flowchart showing a procedure of request signal transmission processing performed by the monitoring apparatus 10 according to the present embodiment. The processing unit 11 of the monitoring device 10 according to the present embodiment determines whether or not the ignition switch of the vehicle 1 has been switched from the off state to the on state (step S11). When the ignition switch is not switched from the off state to the on state (S11: NO), the processing unit 11 waits until the ignition switch is switched from the off state to the on state.

When the ignition switch is switched from the off state to the on state (S11: YES), the request signal transmission unit 21 of the processing unit 11 receives a request signal including the antenna ID of the transmission antenna 5 from the first transmission antenna 5. Then, it transmits over a predetermined time T1 (step S12). After completing the transmission of the first request signal, the request signal transmission unit 21 transmits the request signal including the antenna ID of the transmission antenna 5 from the second transmission antenna 5 over a predetermined time T1 without delay. (Step S13). After completing the transmission of the second request signal, the request signal transmission unit 21 transmits the request signal including the antenna ID of the transmission antenna 5 from the third transmission antenna 5 over a predetermined time T1 without delay. (Step S14). After finishing the transmission of the third request signal, the request signal transmission unit 21 transmits the request signal including the antenna ID of the transmission antenna 5 from the fourth transmission antenna 5 over a predetermined time T1 without delay. Then, the request signal transmission process is terminated.

FIG. 8 is a flowchart showing a procedure of response signal transmission processing performed by the sensor device 30 according to the present embodiment. The control unit 31 of the sensor device 30 according to the present embodiment measures the predetermined period T2 by the timer function, and determines whether or not the timing for confirming whether or not a radio signal is received has been reached (step S21). When the reception timing has not been reached (S21: NO), the control unit 31 stands by until the predetermined period T2 has elapsed and the reception timing is reached. When the reception timing is reached S (21: YES), the request signal receiving unit 41 of the control unit 31 receives a radio signal at the radio receiving unit 34 (step S22). The request signal receiver 41 determines whether or not the wireless receiver 34 has received a request signal from the monitoring device 10 (step S23). When the request signal is not received (S23: NO), the request signal receiving unit 41 returns the process to step S21.

When the request signal is received (S23: YES), the identification information acquisition unit 42 of the control unit 31 acquires the antenna ID included in the received request signal (step S24). The response signal transmission unit 43 of the control unit 31 acquires the tire air pressure detection result by the air pressure detection unit 33 (step S25). Moreover, the response signal transmission part 43 acquires sensor ID32a memorize | stored in the memory | storage part 32 (step S26).

Next, the response signal transmission unit 43 transmits a response signal including the tire pressure detection result acquired in step S25, the antenna ID acquired in step S24, and the sensor ID acquired in step S26 to the wireless transmission unit 35. To the monitoring device 10 (step S27). After completing the transmission of the response signal, the response signal transmission unit 43 determines a standby time according to the random number generated by the random number generation function, and waits for a random time by counting the determined standby time by the timer function. (Step S28). After waiting for the random time, the response signal transmission unit 43 transmits the response signal having the same content in the wireless transmission unit 35 (step S29). After completing the transmission of the response signal, the response signal transmission unit 43 waits for the random time determined again (step S30). After waiting for the random time, the response signal transmission unit 43 transmits the response signal having the same content in the wireless transmission unit 35 (step S31), and ends the response signal transmission process.

9 and 10 are flowcharts showing the procedure of the response signal reception process performed by the monitoring apparatus 10 according to the present embodiment. The response signal receiving unit 22 of the processing unit 11 of the monitoring device 10 according to the present embodiment determines whether the wireless receiving unit 15 has received a response signal from any one of the sensor devices 30 (step S41). . When the response signal is not received (S41: NO), the response signal receiving unit 22 waits until the response signal is received. When the response signal is received (S41: YES), the response signal receiving unit 22 temporarily stores the received response signal in a memory such as a buffer (step S42). The response signal receiving unit 22 determines whether or not reception of response signals from all the four sensor devices 30 has been completed (step S43). If reception of all response signals has not been completed (S43: NO), the response signal receiving unit 22 returns the process to step S41.

When reception of all response signals is completed (S43: YES), the sensor position determination unit 23 of the processing unit 11 acquires a combination of the antenna ID and the sensor ID included in the response signal accumulated in a memory such as a buffer ( Step S44). Next, the sensor position determination unit 23 refers to the sensor position information 12b stored in the storage unit 12 (step S45). The sensor position determination unit 23 determines whether or not the combination of the antenna ID and the sensor ID acquired from the response signal matches the combination of the antenna ID and the sensor ID stored in the sensor position information 12b (step S46). . If the two combinations match (S46: YES), the sensor position determination unit 23 advances the process to step S50.

If the two combinations do not match (S46: NO), the sensor position determination unit 23 performs reconfirmation processing (step S47). The reconfirmation process is a process of performing again from the transmission of the request signal to each sensor device 30 to the reception of the response signal, and again acquiring the combination of the antenna ID and the sensor ID included in the response signal. The sensor position determination unit 23 determines whether or not the combination of the antenna ID and sensor ID acquired in the reconfirmation process matches the combination of the antenna ID and sensor ID stored in the sensor position information 12b of the storage unit 12. Determination is made (step S48). If the two combinations match (S48: YES), the sensor position determination unit 23 advances the process to step S50. If the two combinations do not match (S48: NO), the sensor position determination unit 23 updates the sensor position information 12b by storing the antenna ID and sensor ID combination newly acquired from the response signal in the sensor position information 12b. (Step S49), the process proceeds to Step S50.

The processing unit 11 acquires a tire air pressure detection result included in a response signal stored in a memory such as a buffer for the four wheels 3 of the vehicle 1 (step S50). The processing unit 11 determines whether or not there is an abnormality in the tire air pressure by comparing the acquired tire air pressure detection result with a threshold value stored in advance (step S51). When the tire pressure is abnormal (S51: YES), the sensor position determination unit 23 of the processing unit 11 acquires the antenna ID and sensor ID included in the response signal together with the tire pressure detection result determined to be abnormal. Then, the position of the wheel 3 having an abnormality is determined by referring to the sensor position information 12b stored in the storage unit 12 (step S52). Next, the processing unit 11 transmits a command for notification to the notification device 8 through the wired communication unit 13, thereby indicating the position of the wheel 3 and notifying the driver that there is an abnormality in the tire pressure (step S53). The process is terminated. When there is no abnormality in the tire pressure (S51: NO), the processing unit 11 ends the process without performing notification.

FIG. 11 is a flowchart illustrating a procedure of a cycle notification signal transmission process performed by the sensor device 30 according to the present embodiment. The sensor device 30 according to the present embodiment performs a process of transmitting a cycle notification signal for notifying a tire air pressure detection result to the monitoring device 10 at a predetermined cycle. The control unit 31 of the sensor device 30 determines whether or not a predetermined period has elapsed and the timing for transmitting the tire air pressure detection result has been reached (step S61). If it is determined that the transmission timing has not been reached (S61: NO), the control unit 31 waits until the transmission timing is reached.

When the transmission timing is reached (S61: YES), the control unit 31 acquires the tire air pressure detection result by the air pressure detection unit 33 (step S62). Moreover, the control part 31 acquires sensor ID32a memorize | stored in the memory | storage part 32 (step S63). Next, the control unit 31 transmits a cycle notification signal including the tire air pressure detection result acquired in step S62 and the sensor ID acquired in step S63 to the monitoring device 10 by the wireless transmission unit 35 (step S64). ), The process is terminated.

FIG. 12 is a flowchart illustrating a procedure of a period notification signal reception process performed by the monitoring apparatus 10 according to the present embodiment. The processing unit 11 of the monitoring device 10 according to the present embodiment determines whether the wireless reception unit 15 has received a period notification signal from any one of the sensor devices 30 (step S71). When the period notification signal has not been received (S71: NO), the processing unit 11 stands by until the period notification signal is received.

When the periodic notification signal is received (S71: YES), the processing unit 11 acquires the sensor ID included in the received periodic notification signal (step S72). The processing unit 11 refers to the sensor position information 12b stored in the storage unit 12 (step S73). The processing unit 11 acquires the position stored in the sensor position information 12b in association with the sensor ID acquired in step S72, so that the wheel on which the sensor device 30 that is the transmission source of the received periodic notification signal is mounted. 3 is determined (step S74).

Next, the processing unit 11 acquires a tire air pressure detection result included in the received cycle notification signal (step S75). The processing unit 11 determines whether or not there is an abnormality in the tire air pressure by comparing the acquired tire air pressure detection result with a threshold value stored in advance (step S76). When there is an abnormality in the tire pressure (S76: YES), the processing unit 11 indicates the position of the wheel 3 by transmitting a command for notification to the notification device 8 through the wired communication unit 13, and the tire pressure is abnormal. The driver is notified of this (step S77), and the process is terminated. When there is no abnormality in the tire pressure (S76: NO), the processing unit 11 ends the process without performing notification.

<Summary>
In the in-vehicle communication system 100 according to the present embodiment having the above configuration, the monitoring device 10 is provided on the vehicle body of the vehicle 1, and the sensor device 30 is provided on each of the four wheels 3 of the vehicle 1. The vehicle body is provided with four transmission antennas 5 in association with the four wheels 3, and the monitoring device 10 transmits a radio signal from each transmission antenna 5 to the corresponding sensor device 30. The vehicle body is provided with a common receiving antenna 6 for the four sensor devices 30, and the monitoring device 10 receives radio signals from the four sensor devices 30 using the receiving antenna 6.

The monitoring apparatus 10 according to the present embodiment wirelessly transmits request signals including different antenna IDs for each transmission antenna 5 in order from the four transmission antennas 5. The sensor device 30 that has received this request signal acquires the antenna ID included in the received request signal, and transmits a response signal including the acquired antenna ID to the monitoring device 10. The monitoring device 10 that has received the response signal at the reception antenna 6 determines which response signal from the sensor device 30 is corresponding to the request signal transmitted from which transmission antenna 5 based on the antenna ID included in the response signal. can do.

In addition, when the monitoring device 10 sequentially transmits request signals from the four transmission antennas 5, after the transmission of the request signal from one transmission antenna 5, the response signal from the sensor device 30 to the request signal is transmitted. Transmission of a request signal from the next transmission antenna 5 is started without waiting for reception. The monitoring device 10 transmits request signals sequentially from the plurality of transmission antennas 5 in order. The time from the completion of transmission of one request signal to the start of transmission of the next request signal is preferably as short as possible. As a result, the monitoring apparatus 10 completes the process of sequentially transmitting the request signals from the four transmission antennas 5 in comparison with the case of transmitting the next request signal after waiting for the reception of the response signal to the request signal. be able to. When transmission of request signals is performed in order without waiting for reception of response signals, the order of response signals transmitted from a plurality of sensor devices 30 may vary, but the in-vehicle communication system according to the present embodiment In 100, by including the antenna ID in the request signal and the response signal, the monitoring device 10 can determine which sensor device 30 is the response signal even if the order of reception varies.

In addition, the sensor device 30 according to the present embodiment transmits a response signal including the antenna ID included in the received request signal and its own sensor ID to the monitoring device 10. Based on the antenna ID and / or sensor ID included in the response signal received by the reception antenna 6, the monitoring device 10 determines which sensor device 30 is the transmission source of the response signal. The monitoring device 10 stores the correspondence between the antenna ID and the sensor ID and the mounting position of the sensor device 30 in the sensor position information 12b of the storage unit 12, so that the antenna ID and the sensor ID included in the received response signal are stored. Based on the above, it is possible to determine which wheel 3 the sensor device 30 of the transmission source is provided on.

In addition, the monitoring device 10 according to the present embodiment, after finishing transmission of the request signal from one transmission antenna 5, during the time shorter than the transmission time of the response signal transmitted by the sensor device 30, The transmission of the request signal from 5 is started. The time from the completion of transmission of one request signal to the start of transmission of the next request signal is preferably as short as possible. Thereby, the time which the monitoring apparatus 10 requires for the transmission of the radio signal performed between the four sensor apparatuses 30 can be reduced.

Also, the sensor device 30 according to the present embodiment transmits a response signal a plurality of times at random intervals. Accordingly, for example, even when the transmission of response signals by a plurality of sensor devices 30 overlaps, it can be expected that the subsequent transmission of response signals will be performed at different timings. The possibility of receiving a response signal from is increased.

In the present embodiment, a radio signal in the LF band is transmitted from the monitoring device 10 to the sensor device 30 and a radio signal in the UHF band or the RF band is transmitted from the sensor device 30 to the monitoring device 10. The frequency band for wireless communication may be set as appropriate. Further, although the identification information included in the request signal by the monitoring device 10 is the antenna ID given to the transmission antenna 5, it is not limited to this. The identification information included in the request signal does not necessarily have to be attached to the transmission antenna 5, and may be different information with respect to the position of the wheel 3 of the vehicle 1. For example, a random value may be adopted. Good. In the present embodiment, the vehicle 1 having four wheels 3 has been described as an example. However, the present technology may be applied to a vehicle 1 having three or less or five or more wheels 3.

It should be considered that the embodiment disclosed this time is illustrative in all respects and not restrictive. The scope of the present invention is defined not by the above-described meaning but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 vehicle 3 wheel 5 transmitting antenna (transmitting antenna)
6 Receiving antenna (receiving antenna)
8 Notification device 10 Monitoring device (vehicle communication device, vehicle body side communication device)
DESCRIPTION OF SYMBOLS 11 Processing part 12 Memory | storage part 12a Program 12b Sensor position information 13 Wired communication part 14 Wireless transmission part 15 Wireless reception part 21 Request signal transmission part 22 Response signal reception part 23 Sensor position determination part (determination part)
30 Sensor device (wheel side communication device)
31 Control Unit 32 Storage Unit 32a Sensor ID
33 Air Pressure Detection Unit 34 Wireless Reception Unit 34a Reception Antenna 35 Wireless Transmission Unit 35a Transmission Antenna 41 Request Signal Reception Unit 42 Identification Information Acquisition Unit 43 Response Signal Transmission Unit 99 Recording Medium 100 In-vehicle Communication System

Claims

A plurality of transmitting antennas provided on the vehicle body of the vehicle in association with a plurality of wheels of the vehicle, respectively, and a plurality of antennas provided on the plurality of wheels, respectively, using a receiving antenna provided on the vehicle body. In the in-vehicle communication device that performs wireless communication with the wheel side communication device,
A request signal transmission unit that wirelessly transmits a request signal including identification information different for each transmission antenna from the plurality of transmission antennas;
A response signal receiving unit that receives, using the receiving antenna, a response signal that the wheel side communication device that has received the request signal transmitted by the request signal transmitting unit transmits including the identification information included in the request signal. And
The request signal transmitter, after finishing the transmission of the request signal from the first transmitting antenna, without waiting for the response signal from the wheel side communication device to receive the request signal, the second An in-vehicle communication device that starts transmission of the request signal from a transmitting antenna.
The in-vehicle communication device according to claim 1, wherein the request signal transmission unit transmits the request signal sequentially from the plurality of transmission antennas.
The in-vehicle device according to claim 1, further comprising: a determination unit that determines the wheel side communication device that is a transmission source of the response signal based on identification information included in the response signal received by the response signal reception unit. Communication device.
The request signal transmission unit, after finishing transmitting the request signal from the first transmitting antenna, during a time shorter than the transmission time of the response signal transmitted by the wheel side communication device, The in-vehicle communication device according to any one of claims 1 to 3, wherein transmission of the request signal from the transmitting antenna is started.
A plurality of wheel side communication devices respectively provided on a plurality of wheels of the vehicle;
A vehicle body side that performs wireless communication with the wheel side communication device using a plurality of transmitting antennas provided on the vehicle body of the vehicle in association with the wheels and a receiving antenna provided on the vehicle body. A communication device,
The vehicle body side communication device is:
A request signal transmission unit that wirelessly transmits a request signal including identification information different for each transmission antenna from the plurality of transmission antennas;
A response signal receiving unit that receives a response signal from the wheel side communication device with respect to the request signal transmitted by the request signal transmitting unit using the receiving antenna;
The wheel side communication device is:
A request signal receiving unit for receiving a request signal from the vehicle body side communication device;
An identification information acquisition unit for acquiring identification information included in the request signal received by the request signal reception unit;
A response signal transmission unit that wirelessly transmits a response signal including the identification information acquired by the identification information acquisition unit,
The request signal transmission unit of the vehicle body side communication device waits for reception of a response signal from the wheel side communication device to the request signal after completing transmission of the request signal from the first transmitting antenna. The on-vehicle communication system starts transmission of the request signal from the second transmitting antenna.
The vehicle-mounted communication system according to claim 5, wherein the response signal transmission unit of the wheel side communication device transmits the response signal a plurality of times at random intervals.
The response signal transmitter of the wheel side communication device transmits a response signal including second identification information attached to the wheel side communication device,
The vehicle body side communication device includes a determination unit that determines the wheel side communication device that is the transmission source of the response signal based on identification information and second identification information included in the response signal received by the response signal reception unit. The in-vehicle communication system according to claim 5 or 6.
In-vehicle communication devices mounted on vehicles
Using a plurality of transmission antennas provided on a vehicle body of the vehicle in association with a plurality of wheels of the vehicle, a request signal including identification information different for each transmission antenna is transmitted from the plurality of transmission antennas. Wirelessly in turn,
A receiving antenna provided in the vehicle body for transmitting a response signal including identification information included in the request signal when a plurality of wheel side communication devices provided in the plurality of wheels respectively receive the request signal Execute the process to receive using
When wirelessly transmitting the request signals from the plurality of transmitting antennas in order, after the transmission of the request signal from the first transmitting antenna is completed, a response signal from the wheel side communication device to the request signal A communication program for starting transmission of the request signal from the second transmission antenna without waiting for reception of the second transmission antenna.
A plurality of wheel side communication devices respectively provided on a plurality of wheels of a vehicle and a vehicle body side communication device mounted on a vehicle body of the vehicle are associated with the wheels, and a plurality of transmission devices provided on the vehicle body. In a communication method for performing wireless communication using an antenna and a receiving antenna provided on the vehicle body,
The vehicle body side communication device wirelessly transmits a request signal including identification information different for each transmission antenna in order from the plurality of transmission antennas,
The wheel side communication device receives a request signal from the vehicle body side communication device, acquires identification information included in the received request signal, wirelessly transmits a response signal including the acquired identification information,
The vehicle body side communication device receives a response signal from the wheel side communication device using the receiving antenna,
When the vehicle body side communication device wirelessly transmits the request signals from the plurality of transmitting antennas in order, after the transmission of the request signals from the first transmitting antenna, the wheel side with respect to the request signals A communication method, wherein transmission of the request signal from the second transmitting antenna is started without waiting for reception of a response signal from the communication device.