WO2019176503A1

WO2019176503A1 - In-vehicle communication device, in-vehicle communication system, communication program, and communication method

Info

Publication number: WO2019176503A1
Application number: PCT/JP2019/006772
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: 2019-02-22
Publication date: 2019-09-19
Also published as: JP2019156281A

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: generates a request signal by modulating transmission data including identification information defined for respective transmission antennas; simultaneously transmits, from each transmission antenna, the request signal generated for each transmission antenna; receives, by using a reception antenna, a response signal transmitted by a wheel-side communication device that received the transmitted request signal, the response signal including the identification information included in the request signal; and on the basis of the identification information included in reception data obtained by demodulating the received response signal, determines which of a plurality of wheels is provided with the wheel-side communication device that transmitted the response signal.

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 the present aspect includes a plurality of transmission antennas that are spaced apart from a vehicle and a plurality of transmission antennas that are provided on a plurality of wheels of the vehicle using reception antennas that are provided on the vehicle. In the in-vehicle communication device that performs wireless communication with the wheel side communication device, a generation unit that generates a request signal by modulating transmission data including identification information determined for each of the transmission antennas, and the generation unit The request signal transmitting unit that transmits the request signal for each of the transmitting antennas generated from the transmitting antenna simultaneously, and the wheel side communication device that has received the request signal transmitted by the request signal transmitting unit is the request signal. A response signal to be transmitted using the reception antenna, and a demodulator that demodulates the response signal received by the response signal receiver. And a determination unit that determines on which of the plurality of wheels the wheel side communication device that is the transmission source of the response signal is mounted based on identification information included in the reception data demodulated by the demodulation unit. Prepare.

The in-vehicle communication system according to the present aspect is provided with a plurality of wheel side communication devices respectively provided on a plurality of wheels of a vehicle, a plurality of transmission antennas arranged separately from the vehicle, and the vehicle. A vehicle body side communication device that performs wireless communication with the plurality of wheel side communication devices using a reception antenna, and the vehicle body side communication device includes identification information defined for each of the transmission antennas. A generation unit that generates a request signal by modulating transmission data, and a request signal transmission unit that simultaneously transmits the request signal for each of the transmission antennas generated by the generation unit from each transmission antenna, The wheel-side communication device includes a request signal receiving unit that receives the request signal that is simultaneously transmitted and superimposed from the plurality of transmitting antennas, and identification information included in the request signal received by the request signal receiving unit. And a response signal transmission unit that transmits a response signal including the identification information acquired by the identification information acquisition unit, the vehicle body side communication device further includes the wheel side communication device. A response signal receiving unit that receives the transmitted response signal using the receiving antenna, a demodulating unit that demodulates the response signal received by the response signal receiving unit, and an identification included in the reception data demodulated by the demodulating unit And a determination unit that determines which of the plurality of wheels is equipped with the wheel-side communication device that is the transmission source of the response signal based on the information.

The communication program according to this aspect includes a plurality of transmission antennas arranged separately from the vehicle, and a plurality of reception antennas provided on the vehicle, and a plurality of transmission antennas provided respectively on the plurality of wheels of the vehicle. A request signal is generated by modulating transmission data including identification information defined for each of the transmission antennas to the in-vehicle communication device that performs wireless communication with the wheel side communication device, and the generated transmission antennas The request signal is transmitted simultaneously from each transmitting antenna, and the response signal transmitted by the wheel side communication device including the identification information included in the request signal is received using the receiving antenna. Receiving, demodulating the received response signal, and based on the identification information included in the demodulated reception data, the wheel side communication device of the response signal is sent to any of the plurality of wheels. To execute a process of determining whether it is loading.

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 arranged separately from the vehicle body. In a communication method for performing wireless communication using a plurality of transmission antennas and a reception antenna provided in the vehicle, the vehicle body side communication device includes transmission data including identification information defined for each of the transmission antennas. The vehicle body side communication device transmits the generated request signal for each transmission antenna simultaneously from each transmission antenna, and the wheel side communication device transmits the plurality of transmission signals. The request signal transmitted and superimposed simultaneously from the trust antenna is received, the wheel side communication device acquires the identification information included in the received request signal, and the wheel side communication device acquires A response signal including other information is transmitted, the vehicle body side communication device receives the response signal transmitted by the wheel side communication device using the reception antenna, and the vehicle body side communication device receives the response signal. And determining which of the plurality of wheels the wheel-side communication device that is the transmission source of the response signal is mounted on the basis of the identification information included in the demodulated reception data.

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 schematic diagram which shows an example of an ASK modulation system. It is a schematic diagram which shows an example of the data structure of a request signal. It is a schematic diagram for demonstrating the superimposition of the response signal corresponded to individual data. 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 time concerning transmission of the request signal from a monitoring apparatus to four sensor apparatuses. It is a schematic diagram for demonstrating the time concerning transmission of the response signal from a sensor apparatus to the monitoring apparatus. It is a flowchart which shows the procedure of the communication process which the monitoring apparatus which concerns on this Embodiment performs. It is a flowchart which shows the procedure of the communication process which the monitoring apparatus which concerns on this Embodiment performs. It is a flowchart which shows the procedure of the communication process which the sensor 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. It is a schematic diagram for demonstrating sharing of the transmission antenna which concerns on this Embodiment.

[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 is provided on each of a plurality of wheels of the vehicle by using a plurality of transmission antennas arranged separately from the vehicle and a reception antenna provided on the vehicle. In the in-vehicle communication device that performs wireless communication with the plurality of wheel-side communication devices, a generation unit that generates a request signal by modulating transmission data including identification information determined for each of the transmission antennas; A request signal transmitting unit that transmits the request signal for each of the transmitting antennas generated by the generating unit simultaneously from each transmitting antenna; and the wheel side communication device that has received the request signal transmitted by the request signal transmitting unit. A response signal receiving unit that receives a response signal including identification information included in the request signal using the receiving antenna, and a response signal received by the response signal receiving unit is demodulated. And a determination unit that determines on which of the plurality of wheels the wheel side communication device that is the transmission source of the response signal is based on identification information included in the reception data demodulated by the demodulation unit With.

In this aspect, an in-vehicle communication device is provided on the vehicle body of the vehicle, and a wheel side communication device is provided on each of the plurality of wheels of the vehicle. A plurality of transmitting antennas are spaced apart from each other on the vehicle body, and the in-vehicle communication device transmits radio signals to the plurality of wheel side communication devices using the transmitting antenna. The vehicle body is provided with a reception antenna common to the plurality of wheel side communication devices, and the in-vehicle communication device receives a radio signal from the wheel side communication device using the reception antenna.
Different identification information is assigned to each of the plurality of transmitting antennas. The in-vehicle communication device generates transmission data including identification information for each transmission antenna, and simultaneously transmits request signals obtained by modulating the transmission data from a plurality of transmission antennas. By simultaneously transmitting request signals including different identification information from a plurality of transmitting antennas, the plurality of request signals are superimposed and received by the wheel side communication device. The waveform when the superimposed request signal is received by each wheel-side communication device changes according to the distance and position of the wheel-side communication device with respect to a plurality of transmission antennas. The wheel side communication device receives the superimposed request signal, acquires identification information included in the received request signal, and transmits a response signal including the acquired identification information to the in-vehicle communication device.
The in-vehicle communication device receives the response signal from the wheel side communication device and acquires the identification information included in the received response signal. The identification information included in the response signal received by the in-vehicle communication device is obtained by superimposing a plurality of different identification information. Therefore, the in-vehicle communication device can determine which of the plurality of wheels the wheel-side communication device that is the transmission source of the response signal is mounted on the basis of the identification information included in the response signal. .
As a result, the in-vehicle communication device can simultaneously transmit request signals to the plurality of wheel side communication devices as compared with a configuration in which wireless communication is sequentially performed with the plurality of wheel side communication devices, for example. The time required for wireless communication with the side communication device can be shortened.

(2) It is preferable that the generation unit modulates the transmission data by an ASK (Amplitude Shift Keying) modulation method.

In this aspect, the in-vehicle communication device modulates transmission data including identification information by an ASK (Amplitude Shift Keying) modulation method. The ASK modulation method is a method of modulating each bit included in digital data to an amplitude corresponding to a value of 0/1, and the amplitude changes when a plurality of signals having different values are superimposed. When the amplitude of the request signal received by each wheel side communication device is determined with an appropriate threshold, the identification information acquired from this request signal depends on the presence / absence of superimposition and the number of superimposed signals. For this reason, it becomes possible to judge the position of each wheel side communication apparatus based on the identification information contained in the request signal received by each wheel side communication apparatus.

(3) The vehicle is provided with the wheels respectively on the right front, right rear, left front, and left rear of the vehicle body, and the plurality of transmission antennas are provided on the right side of the vehicle body. And a left transmission antenna provided near the left side of the vehicle body and a rear transmission antenna provided near the rear side of the vehicle body.

In this aspect, the vehicle is provided with wheels at four locations on the right front, right rear, left front and left rear of the vehicle body. The vehicle body is provided with a right transmitting antenna provided close to the right side, a left transmitting antenna provided close to the left side, and a rear transmitting antenna provided close to the rear side. Thus, the radio signal from the right transmission antenna is received by the wheel side communication device provided on the right wheel, and the radio signal from the left transmission antenna is received by the wheel side communication device provided on the left wheel. The wheel-side communication device that is received and provided on the rear wheel can be expected to receive a radio signal from the rear transmission antenna. Thereby, it can be expected that each wheel side communication device receives radio signals from one or two transmitting antennas.

(4) The transmission range of the response signal transmitted from the right transmission antenna includes the right front and right rear wheels, and does not include the left front and left rear wheels, and is transmitted from the left transmission antenna. The response signal transmission range includes the left front and left rear wheels, and does not include the right front and right rear wheels, and the response signal transmission range transmitted from the rear transmission antenna. Preferably, the right rear and left rear wheels are included, and the right front and left front wheels are not included.

In this aspect, the transmission range of the request signal transmitted from the right transmitting antenna includes the right front and right rear wheels and does not include the left front and left rear wheels. The transmission range of the request signal transmitted from the left transmitting antenna includes the left front and left rear wheels and does not include the right front and right rear wheels. The transmission range of the request signal transmitted from the rear transmission antenna includes right rear and left rear wheels, and does not include right front and left front wheels. Thereby, the wheel side communication apparatus provided in the right front wheel receives the request signal from the right transmitting antenna. The wheel side communication device provided on the left front wheel receives a request signal from the left transmitting antenna. The wheel side communication device provided on the right rear wheel receives a signal in which the request signal from the right transmission antenna and the request signal from the rear transmission antenna are superimposed. The wheel side communication device provided on the left rear wheel receives a signal in which a request signal from the left transmission antenna and a request signal from the rear transmission antenna are superimposed. Therefore, the request signals received by the four wheel side communication devices can be made different from each other.

(5) It is preferable that the transmitting antenna is an antenna shared with a system that performs wireless communication with a portable communication device to control the door lock of the vehicle.

In this aspect, antennas shared with the vehicle door lock control system are used as the right transmitting antenna, left transmitting antenna, and rear transmitting antenna. The door lock control system is a system that performs wireless communication with a portable communication device possessed by a user, and locks / unlocks the door of the vehicle according to the communication result. Since the antennas used in the door lock control system are often provided on the right side, left side, and rear side of the vehicle, the number of antennas mounted on the vehicle can be reduced by sharing these antennas.

(6) An 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 transmission antennas arranged separately from the vehicle, and the vehicle A vehicle body side communication device that performs wireless communication with the plurality of wheel side communication devices using a receiving antenna provided, wherein the vehicle body side communication device is identified for each transmission antenna A generation unit that generates a request signal by modulating transmission data including information, and a request signal transmission unit that simultaneously transmits the request signal for each transmission antenna generated by the generation unit from each transmission antenna. The wheel-side communication device includes a request signal receiving unit that receives the request signal that is simultaneously transmitted and superimposed from the plurality of transmitting antennas, and an information included in the request signal received by the request signal receiving unit. An identification information acquisition unit that acquires information; and a response signal transmission unit that transmits a response signal including the identification information acquired by the identification information acquisition unit. The vehicle body side communication device further includes the wheel side communication device. Included in the received data demodulated by the demodulator, the demodulator for demodulating the response signal received by the response signal receiver, and the response signal received by the demodulator And a determination unit that determines which of the plurality of wheels is equipped with the wheel-side communication device that is the transmission source of the response signal based on the identification information.

In this aspect, similarly to aspect (1), the time required for wireless communication between the vehicle body side communication device and the plurality of wheel side communication devices can be shortened.

(7) It is preferable that the reception timing of the request signal by the plurality of wheel side communication devices is different timing.

In this aspect, the plurality of wheel side communication devices provided on the wheels of the vehicle receive request signals from the vehicle body side communication devices at different timings. Thereby, the transmission timing of the response signal of each wheel side communication device according to the reception of the request signal can be set to a different timing, and the transmission of the response signal by the plurality of wheel side communication devices is performed in an overlapping manner. Can be avoided.

(8) It is preferable that the response signal transmission unit of the wheel side communication device transmits the response signal a plurality of times with a random time interval.

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.

(9) 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 determination unit of the vehicle body side communication device receives the response The determination is preferably performed based on the identification information and the second identification information included in the response signal received by the signal reception unit.

In this aspect, the response information includes the identification information included in the request signal received by the wheel side communication device and the second identification information attached to itself. 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.

(10) A communication program according to this aspect is provided on each of a plurality of wheels of the vehicle using a plurality of transmission antennas arranged separately from the vehicle and a reception antenna provided on the vehicle. A request signal is generated by modulating transmission data including identification information determined for each transmission antenna in an in-vehicle communication device that performs wireless communication with a plurality of wheel-side communication devices. A request signal for each trusted antenna is simultaneously transmitted from each transmitting antenna, and the response signal transmitted by the wheel side communication device that has received the request signal including the identification information included in the request signal is transmitted to the receiving antenna. Is used to demodulate the received response signal, and based on the identification information included in the demodulated received data, the wheel side communication device of the response signal To execute a process of determining whether it is mounted in Les.

(11) 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 separated from the vehicle body. In a communication method for performing wireless communication using a plurality of transmission antennas arranged and a reception antenna provided in the vehicle, the vehicle body side communication device uses identification information determined for each transmission antenna. The transmission signal is modulated to generate a request signal, and the vehicle body side communication device transmits the generated request signal for each of the transmission antennas simultaneously from each of the transmission antennas. The request signals transmitted and superimposed simultaneously from a plurality of transmitting antennas are received, the wheel side communication device acquires identification information included in the received request signals, and the wheel side communication device receives The vehicle body side communication device receives the response signal transmitted by the wheel side communication device using the reception antenna, and the vehicle body side communication device receives the response received. The signal is demodulated, and based on the identification information included in the demodulated reception data, it is determined on which of the plurality of wheels the wheel side communication device that is the transmission source of the response signal is mounted.

[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 and notifies the driver of information such as the presence or absence of abnormality for the four wheels 3 provided in the vehicle 1. 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. 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 a sensor device 30 is provided on each wheel 3. 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 three transmission antennas 51 to 53 for the monitoring device 10 to transmit LF band radio signals to the four sensor devices 30. For example, the first transmission antenna 51 is provided on the right side surface portion of the vehicle 1, the second transmission antenna 52 is provided on the left side surface portion of the vehicle 1, and the third transmission antenna 53 is provided on the rear portion of the vehicle 1. Yes. Further, the first transmission antenna 51 and the second transmission antenna 52 are provided at a substantially central position between the front wheel 3 and the rear wheel 3 in the front-rear direction of the vehicle 1. The third transmission antenna 53 is provided at a substantially central position between the right wheel 3 and the rear wheel 3 in the left-right direction of the vehicle 1. Note that the mounting positions of the three transmission antennas 51 to 53 shown in FIG. 1 are merely examples, and the present invention is not limited to this.

A range 51a in which the sensor device 30 can receive a request signal transmitted from the first transmission antenna 51 is illustrated as a two-dot chain line region in FIG. The request signal from the first transmitting antenna 51 is received by the two sensor devices 30 provided on the right front side wheel and the right rear side wheel 3 of the vehicle 1, and the other sensor devices 30 do not receive this request signal. The range 51a is set as appropriate. Similarly, a range 52a in which the sensor device 30 can receive a request signal transmitted from the second transmitting antenna 52 is illustrated as a two-dot chain line region in FIG. The request signal from the second transmission antenna 52 is received by the two sensor devices 30 provided on the left front wheel 3 and the left rear wheel 3 of the vehicle 1, and the other sensor devices 30 do not receive this request signal. 52a is appropriately set. Similarly, a range 53a in which the sensor device 30 can receive a request signal transmitted from the third transmitting antenna 53 is illustrated as a two-dot chain line region in FIG. The request signal from the third transmitting antenna 53 is received by the two sensor devices 30 provided on the right rear and left rear wheels 3 of the vehicle 1 so that the other sensor devices 30 do not receive the request signal. The range 53a is appropriately set.

In other words, the sensor device 30 provided on the right front wheel 3 of the vehicle 1 receives the request signal transmitted from the first transmission antenna 51. The sensor device 30 provided on the right rear wheel 3 of the vehicle 1 receives the request signals transmitted from the first transmission antenna 51 and the third transmission antenna 53. The sensor device 30 provided on the left front wheel 3 of the vehicle 1 receives the request signal transmitted from the second transmission antenna 52. The sensor device 30 provided on the left rear wheel 3 of the vehicle 1 receives the request signals transmitted from the second transmission antenna 52 and the third transmission antenna 53.

The monitoring device 10 transmits request signals for requesting the transmission of response signals to the sensor devices 30 from the three transmission antennas 51 to 53 as radio signals in the LF band. For example, the monitoring device 10 can request transmission of a tire air pressure detection result of each wheel 3 and / or identification information attached to each sensor device 30 by transmitting a request signal. The sensor device 30 that has received the request signal from the monitoring device 10 transmits a response signal including at least identification information (hereinafter referred to as sensor ID) of the device itself to the monitoring device 10 as a UHF band radio signal. The response signal transmitted by the sensor device 30 may include information on the detection result of the tire air pressure of the wheel 3. The monitoring device 10 receives the UHF band response signal transmitted by the sensor device 30 at the receiving antenna 6.

The monitoring device 10 according to the present embodiment employs an ASK (Amplitude Shift Keying) modulation method (amplitude shift modulation method) for transmitting a request signal to the sensor device 30. FIG. 2 is a schematic diagram illustrating an example of the ASK modulation method. The ASK modulation method is one of methods for converting digital data represented by binary values “0” and “1” into a signal for wireless transmission using a carrier wave such as a sine wave. The ASK modulation method is a method of performing modulation by changing the amplitude corresponding to the bit string of transmission data while maintaining the frequency and phase of the carrier wave. In the ASK modulation method, for example, the amplitude of a carrier wave is reduced with respect to “0” of transmission data, and the amplitude of the carrier wave is increased with respect to “1” of transmission data. As shown in FIG. 2, the ECU 3 according to the present embodiment controls a switch or the like according to the value of transmission data, and turns on / off a carrier wave to output a simple ASK modulation method (a modulated wave is obtained). This method can also be called an on-off modulation method) and modulates transmission data.

Further, in the present embodiment, the request signal transmitted from the transmission antennas 51 to 53 by the monitoring apparatus 10 includes common data common to all the transmission antennas 51 to 53 and individual data different for each of the transmission antennas 51 to 53. include. FIG. 3 is a schematic diagram illustrating an example of a data configuration of the request signal. The request signal transmitted from the monitoring device 10 to the sensor device 30 includes, for example, a header, common data, individual data, and a footer. The header and footer include, for example, data defined by a communication protocol between the monitoring device 10 and the sensor device 30. The common data can include, for example, identification information of the vehicle 1 or a command to the sensor device 30.

The individual data included in the request signal is 2-bit data in the present embodiment, and stores 2-bit antenna IDs individually assigned to the transmission antennas 51 to 53. In the present embodiment, individual antenna IDs are assigned to the three transmission antennas 51 to 53 provided in the vehicle 1 in advance. In this embodiment, ID = “00” is assigned to the right transmission antenna 51, ID = “01” is assigned to the left transmission antenna 52, and ID = “10” is assigned to the rear transmission antenna 53. "Is assigned. However, the specific values of these IDs are only examples, and are not limited to these. Any values may be used as long as the following processing can be realized.

The monitoring apparatus 10 according to the present embodiment modulates transmission data having the same common data, header, and footer and different individual data by the ASK modulation method, and uses a radio signal obtained by the modulation as a request signal, Transmission is simultaneously performed from the transmission antennas 51 to 53 corresponding to the individual data included in this signal. Request signals transmitted simultaneously from the plurality of transmission antennas 51 to 53 are superimposed at the locations where the transmission ranges 51a to 53a overlap. Since the header, common data, and footer included in the plurality of request signals are the same, the signal waveform does not change even when the plurality of request signals are superimposed (the amplitude may be amplified). However, since the individual data included in each request signal has a different value for each of the transmission antennas 51 to 53 as described above, when a plurality of request signals are superimposed, the signal waveform changes.

FIG. 4 is a schematic diagram for explaining the superimposition of response signals corresponding to individual data. 4 shows the waveform of the carrier wave. Below the waveform of the carrier wave in FIG. 4, individual data included in the transmission data transmitted from the left transmission antenna 51 and its modulated wave, and individual data included in the transmission data transmitted from the rear transmission antenna 53. And its modulated wave. 4 shows the superimposed wave when the modulated wave transmitted from the transmission antenna 52 and the modulated wave transmitted from the transmission antenna 53 are superimposed.

The modulated wave modulated by the ASK modulation method has a waveform in which a carrier wave is output corresponding to “1” included in the individual data. For this reason, when two modulated waves corresponding to two individual data having different values are superimposed, a superimposed wave having a waveform corresponding to the logical sum data of the individual data is obtained. In the case of the illustrated example, when two modulated waves corresponding to the individual data “01” and the individual data “00” are superimposed, the superimposed wave has a signal waveform with the individual data “11”.

When the request signal is received only from the right transmitting antenna 51 that transmits the request signal of the individual data “00”, the individual data included in the received request signal is “00”. When the request signal is received only from the left transmission antenna 52 that transmits the request signal of the individual data “01”, the individual data included in the received request signal is “01”. When the request signal is received only from the rear transmission antenna 53 that transmits the request signal of the individual data “10”, the individual data included in the received request signal is “10”.

On the other hand, in the overlapping range of the transmission range 51 a of the right transmission antenna 51 and the transmission range 53 b of the rear transmission antenna 53, a superimposed signal of the request signal from the transmission antenna 51 and the request signal from the transmission antenna 53. Is received, the individual data included in the received request signal is the logical sum “10” of “00” and “10”. Also, in the overlapping range of the transmission range 52a of the left transmission antenna 52 and the transmission range 53b of the rear transmission antenna 53, a superimposed signal of the request signal from the transmission antenna 52 and the request signal from the transmission antenna 53 is received. Therefore, the individual data included in the received request signal is a logical sum “11” of “01” and “10”.

As a result, in the example shown in FIG. 1, the individual data included in the request signal received by the sensor device 30 provided on the right front wheel 3 of the vehicle 1 is “00”. The individual data included in the request signal received by the sensor device 30 provided on the right rear wheel 3 of the vehicle 1 is “10”. The individual data included in the request signal received by the sensor device 30 provided on the left front wheel 3 of the vehicle 1 is “01”. The individual data included in the request signal received by the sensor device 30 provided on the left rear wheel 3 of the vehicle 1 is “11”.

Each sensor device 30 that has received the request signal from the monitoring device 10 acquires individual data included in the received request signal. The sensor device 30 generates a response signal including individual data acquired from the request signal, a tire air pressure detection result, its own sensor ID, and the like, and transmits the response signal to the monitoring device 10. The monitoring device 10 that has received the response signal from the sensor device 30 determines which wheel 3 is provided with the sensor device 30 that is the transmission source of this response signal, based on the individual data included in the response signal. Can do.

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 this response signal is transmitted based on the individual data and 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 individual data. The monitoring device 10 that has received the periodic signal from the sensor device 30 at the receiving antenna 6, from which sensor device 30 the signal is transmitted based on the sensor ID included in the received signal. Determine.

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 antennas 51 to 53 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. 5 is a block diagram showing 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. 6 is a schematic diagram illustrating an example of the sensor position information 12b. In the present embodiment, the sensor position information 12b stores the mounting position of the sensor device 30, the individual data corresponding to the mounting position, and the sensor ID assigned to the sensor device 30 in association with each other. . In this example, the mounting positions of the sensor device 30 are four types of right front, right rear, left front, and left rear, the individual data are four types of “00”, “01”, “10”, and “11”, and the sensor ID Are S1 to S4. The individual data is individual data included in a response signal transmitted by the sensor device 30 mounted on the corresponding wheel 3. Although the correspondence between the mounting position and the individual data 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, three transmission antennas 51 to 53 are connected via individual signal lines. The radio transmission unit 14 transmits an SK band radio signal having a frequency of 30 kHz to 300 kHz by outputting to the transmission antennas 51 to 53 an electric signal obtained by ASK modulation of transmission data provided from the processing unit 11. In the present embodiment, the wireless transmission unit 14 transmits request signals simultaneously from the three transmission antennas 51 to 53 to the four sensor devices 30 provided on the wheel 3. The request signals transmitted simultaneously at this time are obtained by performing ASK modulation on transmission data that is different in individual data and common to other data. The assignment of the individual data for each of the transmission antennas 51 to 53 may be performed by the processing unit 11 or the wireless transmission unit 14. For example, the processing unit 11 gives three pieces of transmission data that differ only in individual data to the wireless transmission unit 14, and the wireless transmission unit 14 modulates the given three pieces of transmission data and transmits them from the corresponding transmission antennas 51 to 53, respectively. You may transmit simultaneously. Further, for example, the processing unit 11 gives transmission data not including individual data to the radio transmission unit 14, and the radio transmission unit 14 adds different individual data to the given transmission data and then modulates the corresponding transmission antennas. You may transmit simultaneously from 51-53.

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. . The UHF band radio signal transmitted from the sensor device 30 to the monitoring device 10 does not need to be modulated by a modulation scheme other than the ASK modulation scheme, and any modulation scheme may be employed.

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 transmitter 21 controls the operation of the wireless transmitter 14 to request the four sensor devices 30 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, for example, transmission data including a command for requesting a tire air pressure detection result and supplies the transmission data to the wireless transmission unit 14, thereby request signals having different individual data from the three transmission antennas 51 to 53. Transmission can be performed by the wireless transmission unit 14.

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 the tire air pressure detection result, individual data, and 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. The response signal receiving unit 22 gives the individual data and sensor ID acquired from the received data to the sensor position determining unit 23.

Based on the individual data and 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 individual code included in the response signal is “00” and the sensor ID is S1, the sensor position determination unit 23 transmits the response signal based on the sensor position information 12b illustrated in FIG. It can be determined that the original is the sensor device 30 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 individual data 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 individual data 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 individual data and the sensor ID does not match a plurality of times. .

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 individual data. 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. 7 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 individual data 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 pressure detection result, the individual data 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. 8 is a schematic diagram for explaining times related to transmission of request signals from the monitoring device 10 to the four sensor devices 30. FIG. 8 is a timing chart showing how the request signal and the response signal are transmitted and received. The transmission timing of the request signal from the transmission antennas 51 to 53 is shown on the upper side, and the request by the four sensor devices 30 is shown on the lower side. The signal reception 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. At this time, the monitoring device 10 transmits request signals to the four sensor devices 30 simultaneously by transmitting request signals from the three transmission antennas 51 to 53 simultaneously.

The monitoring apparatus 10 performs simultaneous transmission of request signals from the three transmission antennas 51 to 53 over a predetermined time T1. At this time, the monitoring apparatus 10 repeats a request signal including a command for requesting transmission of information related to tire pressure and individual data corresponding to the antenna ID of the transmission antenna 5 used for transmission during a predetermined time T1. To send. For example, the predetermined time T1 is set to several hundred milliseconds to several seconds.

The request signal transmitted simultaneously from the three transmission antennas 51 to 53 by the monitoring device 10 is received by the sensor device 30 of each wheel 3. Each sensor device 30 repeatedly receives the 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.

Further, the reception timings of the request signals by the four sensor devices 30 are not synchronized and are performed at each timing. However, this is such that the reception timings of the four sensor devices 30 do not need to be intentionally synchronized, and the reception timings of the four sensor devices 30 do not need to be intentionally different. The period T2 at which each sensor device 30 receives the request signal is several hundred milliseconds to several seconds, and the time required for one reception is about several milliseconds, so the reception timing of the four sensor devices 30 is intentionally set. Unless synchronized, it is expected that the reception timings of the four sensor devices 30 will naturally shift. Even if the reception timings of the plurality of sensor devices 30 coincide, there is no problem in receiving the request signal by each sensor device 30. In such a case, there may be a problem that the transmission timings of the response signals by the plurality of sensor devices 30 overlap, but in the in-vehicle communication system 100 according to the present embodiment, this can be done by shifting the transmission timing of the subsequent response signals. Has solved.

Request signals transmitted from the three transmission antennas 51 to 53 are received by the four sensor devices 30. Each sensor device 30 acquires a tire air pressure detection result, acquires individual data from the received request signal, and transmits a response signal including the tire air pressure detection result, the individual data, and its own sensor ID. . FIG. 9 is a schematic diagram for explaining a time related to transmission of a response signal from the sensor device 30 to the monitoring device 10. FIG. 9 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.

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. 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. In this way, even if there is an overlap in the transmission of any one response signal by the sensor device 30 transmitting the response signal three times at random intervals, another two responses Signal transmission can be expected to be performed without duplication.

<Flowchart>
FIG. 10 and FIG. 11 are flowcharts showing a procedure of communication 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 includes individual data for each of the transmission antennas 51 to 53 from the three transmission antennas 51 to 53. The request signal is transmitted over a predetermined time T1 (step S12).

Next, the response signal receiving unit 22 of the processing unit 11 determines whether or not the response signal from any of the sensor devices 30 is received by the wireless receiving unit 15 (step S13). When the response signal is not received (S13: NO), the response signal receiving unit 22 waits until the response signal is received. When the response signal is received (S13: YES), the response signal receiving unit 22 temporarily stores the received response signal in a memory such as a buffer (step S14). The response signal receiving unit 22 determines whether or not reception of response signals from all of the four sensor devices 30 has been completed (step S15). If reception of all response signals has not been completed (S15: NO), the response signal receiving unit 22 returns the process to step S13.

When reception of all response signals is completed (S15: YES), the sensor position determination unit 23 of the processing unit 11 acquires a combination of individual data and sensor ID included in the response signal accumulated in a memory such as a buffer ( Step S16). Next, the sensor position determination unit 23 refers to the sensor position information 12b stored in the storage unit 12 (step S17). The sensor position determination unit 23 determines whether or not the combination of the individual data and sensor ID acquired from the response signal matches the combination of the individual data and sensor ID stored in the sensor position information 12b (step S18). . If the two combinations match (S18: YES), the sensor position determination unit 23 proceeds to step S22.

If the combinations do not match (S18: NO), the sensor position determination unit 23 performs reconfirmation processing (step S19). The reconfirmation process is a process of performing again from transmission of a request signal to each sensor device 30 to reception of a response signal, and again acquiring a combination of individual data and sensor ID included in the response signal. The sensor position determination unit 23 determines whether or not the combination of the individual data and sensor ID acquired in the reconfirmation process matches the combination of the individual data and sensor ID stored in the sensor position information 12b of the storage unit 12. Determination is made (step S20). If the two combinations match (S20: YES), the sensor position determination unit 23 proceeds to step S22. When the two combinations do not match (S20: NO), the sensor position determination unit 23 updates the sensor position information 12b by storing the combination of the individual data and the sensor ID newly acquired from the response signal in the sensor position information 12b. (Step S21), the process proceeds to Step S22.

The processing unit 11 acquires the tire air pressure detection result included in the response signal stored in a memory such as a buffer for the four wheels 3 of the vehicle 1 (step S22). 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 S23). When the tire pressure is abnormal (S23: YES), the sensor position determination unit 23 of the processing unit 11 acquires the individual code and sensor ID included in the response signal together with the tire pressure detection result determined to be abnormal. 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 S24). 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 S25). The process is terminated. When there is no abnormality in the tire pressure (S23: NO), the processing unit 11 ends the process without performing notification.

FIG. 12 is a flowchart showing a communication process 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 S31). When the reception timing has not been reached (S31: 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 (S31: YES), the request signal receiving unit 41 of the control unit 31 performs a radio signal reception process in the radio receiving unit 34 (step S32). The request signal receiver 41 determines whether or not the wireless receiver 34 has received a request signal from the monitoring device 10 (step S33). When the request signal has not been received (S33: NO), the request signal receiving unit 41 returns the process to step S31.

When the request signal is received (S33: YES), the identification information acquisition unit 42 of the control unit 31 acquires the individual data included in the received request signal (step S34). The response signal transmission unit 43 of the control unit 31 acquires a tire air pressure detection result by the air pressure detection unit 33 (step S35). Moreover, the response signal transmission part 43 acquires sensor ID32a memorize | stored in the memory | storage part 32 (step S36).

Next, the response signal transmission unit 43 transmits a response signal including the tire air pressure detection result acquired in step S35, the individual code acquired in step S34, and the sensor ID acquired in step S36 to the wireless transmission unit 35. To the monitoring device 10 (step S37). 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 S38). 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 S39). After completing the transmission of the response signal, the response signal transmission unit 43 waits for the determined random time again (step S40). 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 S41), and ends the response signal transmission process.

FIG. 13 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 the predetermined period has passed and the timing for transmitting the tire air pressure detection result has been reached (step S51). If it is determined that the transmission timing has not been reached (S51: NO), the control unit 31 waits until the transmission timing is reached.

When the transmission timing is reached (S51: YES), the control unit 31 acquires the detection result of the tire air pressure by the air pressure detection unit 33 (step S52). Moreover, the control part 31 acquires sensor ID32a memorize | stored in the memory | storage part 32 (step S53). Next, the control unit 31 transmits a cycle notification signal including the tire air pressure detection result acquired in step S52 and the sensor ID acquired in step S53 to the monitoring device 10 by the wireless transmission unit 35 (step S54). ), The process is terminated.

FIG. 14 is a flowchart showing 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 apparatus 10 according to the present embodiment determines whether the wireless reception unit 15 has received a period notification signal from any of the sensor devices 30 (step S61). When the period notification signal has not been received (S61: NO), the processing unit 11 stands by until the period notification signal is received.

When the periodic notification signal is received (S61: YES), the processing unit 11 acquires the sensor ID included in the received periodic notification signal (step S62). The processing unit 11 refers to the sensor position information 12b stored in the storage unit 12 (step S63). The processing unit 11 acquires the position stored in the sensor position information 12b in association with the sensor ID acquired in step S62, 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 S64).

Next, the processing unit 11 acquires a tire air pressure detection result included in the received cycle notification signal (step S65). The processing unit 11 determines whether or not there is an abnormality in the tire pressure by comparing the acquired tire pressure detection result with a threshold value stored in advance (step S66). When there is an abnormality in the tire pressure (S66: 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 S67), and the process is terminated. When there is no abnormality in the tire air pressure (S66: 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. Three transmission antennas 51 to 53 are spaced apart from each other on the vehicle body, and the monitoring device 10 transmits radio signals to the four sensor devices 30 using the transmission antennas 51 to 53. The vehicle body is provided with a common receiving antenna 6 for the four sensor devices 30, and the monitoring device 10 receives a radio signal from the sensor device 30 using the receiving antenna 6.

Different antenna IDs (individual data) are assigned to the three transmission antennas 51 to 53, respectively. The monitoring apparatus 10 generates transmission data including individual data for each of the transmission antennas 51 to 53, and simultaneously transmits request signals obtained by modulating the transmission data from the three transmission antennas 51 to 53. By simultaneously transmitting request signals including different individual data from the three transmission antennas 51 to 53, the three request signals are appropriately superimposed and received by the sensor device 30. The waveform when the superimposed request signal is received by each sensor device 30 changes according to the distance and position of the sensor device 30 with respect to the three transmission antennas 51 to 53. The sensor device 30 receives the superimposed request signal, acquires individual data included in the received request signal, and transmits a response signal including the acquired individual data to the monitoring device 10.

The monitoring device 10 receives the response signal from the sensor device 30 and acquires individual data included in the received response signal. The individual data included in the response signal received by the monitoring device 10 is obtained by superimposing one or a plurality of individual data. Therefore, the monitoring device 10 can determine which of the four wheels 3 the sensor device 30 that is the transmission source of the response signal is mounted on the basis of the individual data included in the response signal. .

As a result, the monitoring device 10 can transmit request signals to the four sensor devices 30 at the same time, for example, compared with a configuration in which wireless communication is sequentially performed with the four sensor devices 30, for example. The time required for wireless communication can be reduced.

In the in-vehicle communication system 100 according to the present embodiment, the monitoring device 10 modulates transmission data including individual data by the ASK modulation method to generate a request signal. The ASK modulation method is a method of modulating each bit included in digital data to an amplitude corresponding to a value of 0/1, and the amplitude changes when a plurality of signals having different values are superimposed. When the amplitude of the request signal received by each sensor device 30 is determined with an appropriate threshold, the individual data acquired from the request signal changes depending on the presence / absence of superimposition, the number of superimposed signals, and the like. Therefore, the position of each sensor device 30 can be determined based on the individual data included in the request signal received by each sensor device 30.

Further, in the present embodiment, the vehicle 1 is provided with wheels 3 at four locations on the right front, right rear, left front and left rear of the vehicle body. The vehicle body of the vehicle 1 includes a transmission antenna 51 provided close to the right side, a transmission antenna 52 provided close to the left side, and a transmission antenna 53 provided close to the rear side. Thus, the sensor device 30 provided on the right wheel 3 receives a radio signal from the right transmission antenna 51, and the sensor device 30 provided on the left wheel 3 receives the radio signal from the left transmission antenna 52. A signal is received, and it can be expected that the sensor device 30 provided on the rear wheel 3 receives a radio signal from the rear transmission antenna 53. Thereby, it can be expected that each sensor device 30 receives radio signals from one or two transmission antennas 51 to 53.

In the present embodiment, the transmission range 51a of the request signal transmitted from the right transmission antenna 51 includes the right front and right rear wheels 3 and does not include the left front and left rear wheels 3. The transmission range 52a of the request signal transmitted from the left transmission antenna 52 includes the left front and left rear wheels 3 and does not include the right front and right rear wheels 3. The transmission range 53a of the request signal transmitted from the rear transmission antenna 53 includes the right rear and left rear wheels 3, and does not include the right front and left front wheels 3. Accordingly, the sensor device 30 provided on the right front wheel 3 receives the request signal from the right transmitting antenna 51. The sensor device 30 provided on the left front wheel 3 receives a request signal from the left transmission antenna 52. The sensor device 30 provided on the right rear wheel 3 receives a signal in which a request signal from the right transmission antenna 51 and a request signal from the rear transmission antenna 53 are superimposed. The sensor device 30 provided on the left rear wheel receives a signal in which a request signal from the left transmission antenna 52 and a request signal from the rear transmission antenna 53 are superimposed. Therefore, the request signals received by the four sensor devices 30 can be different from each other.

In the present embodiment, the four sensor devices 30 provided on the wheels 3 of the vehicle 1 receive request signals from the monitoring device 10 at different timings. Thereby, the transmission timing of the response signal of each sensor device 30 according to reception of the request signal can be set to a different timing, and the transmission of the response signal by the four sensor devices 30 can be avoided.

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

In the present embodiment, the sensor ID attached to the sensor device 30 is transmitted together with the individual data included in the request signal received by the sensor device 30. The monitoring device 10 determines the sensor device 30 that is the transmission source of the response signal based on the individual code and the sensor ID included in the response signal from the sensor device 30. Based on the individual code and sensor ID included in the received response signal, for example, the monitoring device 10 stores the correspondence between the individual code and sensor ID and the mounting position of each sensor ID as the sensor position information 12b. It can be determined on which wheel 3 of the vehicle 1 the sensor device 30 of the transmission source is provided.

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. Moreover, although the monitoring apparatus 10 is configured to perform modulation using the ASK modulation method, the present invention is not limited thereto, and may be configured to perform modulation using a modulation method other than the ASK modulation method. Further, any modulation method may be adopted for transmission of a radio signal from the sensor device 30 to the monitoring device 10. 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.

Further, the three transmission antennas 51 to 53 provided in the in-vehicle communication system 100 according to the present embodiment are not only used for processing as the tire pressure monitoring system as described above, but also, for example, wirelessly with a portable key possessed by the user. It is used for a door lock control system that controls locking / unlocking of the door of the vehicle 1 according to communication. FIG. 15 is a schematic diagram for explaining sharing of transmission antennas 51 to 53 according to the present embodiment. For example, the vehicle 1 includes a door lock control system 101 that controls locking / unlocking of the door of the vehicle 1 together with the above-described in-vehicle communication system 100. The door lock control system 101 includes a lock control device 90 and a lock mechanism 91. The lock control device 90 performs wireless communication with the portable key 92 possessed by the user using the three transmission antennas 51 to 53 and one reception antenna 6. The lock control device 90 outputs a command for locking / unlocking the door to the lock mechanism 91 when wireless communication is established with the regular portable key 92. The lock mechanism 91 locks / unlocks the door by operating an actuator or the like provided on each door of the vehicle 1 in accordance with a command given from the lock control device 90.

Since the in-vehicle communication system 100 and the door lock control system 101 share the three transmission antennas 51 to 53, the number of antennas mounted on the vehicle 1 can be reduced. Generally, antennas for transmitting radio signals in the LF band used for door lock control systems are often provided on the right side, left side, and rear side of a vehicle, so that the above-described in-vehicle communication system 100 transmits a request signal. Sharing with the other transmission antennas 51 to 53 is preferable.

Note that when the in-vehicle communication system 100 and the door lock control system 101 share the transmission antennas 51 to 53, the transmission antennas 51 to 53 cannot be used simultaneously in both systems. It is necessary to switch the system using ~ 53. For example, when the ignition switch of the vehicle 1 is off, the door lock control system 101 uses the transmission antennas 51 to 53, and when the ignition switch is on, the in-vehicle communication system 100 uses the transmission antennas 51 to 53. It can be configured. However, the switching condition is not limited to the state of the ignition switch, and may be various other conditions.

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 6 receiving antenna (receiving antenna)
8 Notification device 10 Monitoring device (vehicle communication device, vehicle body side communication device)
11 Processing Unit 12 Storage Unit 12a Program (Communication Program)
12b Sensor position information 13 Wired communication unit 14 Wireless transmission unit (generation unit)
15 Radio receiver (demodulator)
21 Request signal transmission unit 22 Response signal reception unit 23 Sensor position determination unit (determination unit)
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 51 to 53 Transmission Antenna (Transmission Antenna)
51a to 53a Transmission range 90 Lock control device 91 Lock mechanism 92 Portable key 100 In-vehicle communication system 101 Door lock control system

Claims

Using a plurality of transmitting antennas arranged at a distance from the vehicle and a receiving antenna provided on the vehicle, a plurality of wheel side communication devices respectively provided on a plurality of wheels of the vehicle. In an in-vehicle communication device that performs wireless communication,
A generation unit that generates a request signal by modulating transmission data including identification information determined for each of the transmission antennas;
A request signal transmission unit that transmits the request signal for each of the transmission antennas generated by the generation unit simultaneously from each transmission antenna;
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. When,
A demodulator that demodulates the response signal received by the response signal receiver;
On-vehicle vehicle comprising: a determination unit that determines on which of the plurality of wheels the wheel-side communication device that is the transmission source of the response signal is based on identification information included in the reception data demodulated by the demodulation unit Communication device.
The in-vehicle communication device according to claim 1, wherein the generation unit modulates the transmission data by an ASK (Amplitude Shift Keying) modulation method.
The vehicle is provided with the wheels on the right front, right rear, left front and left rear of the vehicle body,
The plurality of transmitting antennas are provided with a right transmitting antenna provided near the right side of the vehicle body, a left transmitting antenna provided near the left side of the vehicle body, and a rear side of the vehicle body. The in-vehicle communication device according to claim 1, further comprising a rear transmission antenna.
The transmission range of the response signal transmitted from the right transmitting antenna includes the right front and right rear wheels, and does not include the left front and left rear wheels.
The transmission range of the response signal transmitted from the left transmitting antenna includes the left front and left rear wheels, and does not include the right front and right rear wheels.
The in-vehicle communication device according to claim 3, wherein a transmission range of the response signal transmitted from the rear transmission antenna includes the right rear and left rear wheels and does not include the right front and left front wheels. .
The in-vehicle communication device according to claim 3 or 4, wherein the transmitting antenna is an antenna shared with a system that controls a door lock of the vehicle by performing wireless communication with a portable communication device.
A plurality of wheel side communication devices respectively provided on a plurality of wheels of the vehicle;
A vehicle body side communication device that performs wireless communication with the plurality of wheel side communication devices using a plurality of transmission antennas disposed apart from the vehicle and a reception antenna provided in the vehicle; With
The vehicle body side communication device is:
A generation unit that generates a request signal by modulating transmission data including identification information determined for each of the transmission antennas;
A request signal transmission unit that transmits the request signal for each of the transmission antennas generated by the generation unit simultaneously from each of the transmission antennas, and
The wheel side communication device is:
A request signal receiving unit that receives the request signal superimposed and transmitted simultaneously from the plurality of transmitting antennas;
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 transmits a response signal including the identification information acquired by the identification information acquisition unit, and
The vehicle body side communication device further includes:
A response signal receiving unit that receives the response signal transmitted by the wheel side communication device using the receiving antenna;
A demodulator that demodulates the response signal received by the response signal receiver;
A determination unit that determines which of the plurality of wheels the wheel-side communication device of the transmission source of the response signal is based on identification information included in the reception data demodulated by the demodulation unit. In-vehicle communication system.
The in-vehicle communication system according to claim 6, wherein reception timings of the request signals by the plurality of wheel side communication devices are different timings.
The in-vehicle communication system according to claim 6 or 7, 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 said determination part of the said vehicle body side communication apparatus performs determination based on the identification information and 2nd identification information which are contained in the response signal which the said response signal receiving part received. The in-vehicle communication system described in 1.
Using a plurality of transmitting antennas arranged at a distance from the vehicle and a receiving antenna provided on the vehicle, a plurality of wheel side communication devices respectively provided on a plurality of wheels of the vehicle. In-vehicle communication devices that perform wireless communication
A request signal is generated by modulating transmission data including identification information determined for each of the transmission antennas,
The generated request signal for each transmitting antenna is transmitted simultaneously from each transmitting antenna,
The wheel side communication device that has received the request signal receives a response signal that includes the identification information included in the request signal, and receives the response signal using the reception antenna.
Demodulate the received response signal,
A communication program for executing processing for determining which of the plurality of wheels the wheel-side communication device that is the transmission source of the response signal is mounted based on identification information included in demodulated reception data.
A plurality of wheel-side communication devices respectively provided on a plurality of wheels of the vehicle, and a plurality of transmission antennas arranged separately from the vehicle body, and a vehicle body-side communication device mounted on the vehicle body of the vehicle; and In a communication method for performing wireless communication using a receiving antenna provided in the vehicle,
The vehicle body side communication device generates a request signal by modulating transmission data including identification information determined for each transmission antenna,
The vehicle body side communication device transmits the generated request signal for each transmitting antenna simultaneously from each transmitting antenna,
The wheel side communication device receives the request signal superimposed and transmitted simultaneously from the plurality of transmitting antennas,
The wheel side communication device acquires the identification information included in the received request signal,
The wheel side communication device transmits a response signal including the acquired identification information,
The vehicle body side communication device receives the response signal transmitted by the wheel side communication device using the reception antenna,
The vehicle body side communication device demodulates the received response signal, and based on the identification information included in the demodulated reception data, the wheel side communication device that is the transmission source of the response signal is mounted on any of the plurality of wheels. A communication method for determining whether or not