In-vehicle communication device

Abstract

To provide an in-vehicle communication device that does not require a temperature sensor on a signal adjuster side and does not increase the size of the signal adjuster.SOLUTION: In an in-vehicle communication device including an in-vehicle unit installed inside a vehicle and transmitting and receiving wireless signals, an antenna for transmitting and receiving the wireless signals to and from a communication target remote from the vehicle, and a signal adjuster installed in a location with a different temperature environment from the in-vehicle unit and adjusting the amplitude of the wireless signals between the in-vehicle unit and the antenna, the in-vehicle unit is configured to estimate the temperature of the signal adjuster based on current supplied to the signal adjuster.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an in-vehicle communication device. [Background technology]

[0002] In vehicle-to-vehicle communications, a signal conditioner that adjusts the signal level near the transmitting and receiving antennas may be used. Some signal conditioners exchange control signals with an on-board unit that is usually installed inside the vehicle to control the timing of switching between transmitting and receiving, etc., while others are controlled independently by the signal conditioner and do not require a control signal. The latter only transmits and receives signals for vehicle-to-vehicle communications with the on-board unit and supplies power, but cannot notify the on-board unit if an abnormality occurs in the signal conditioner. To notify of an abnormality, a technology has been reported that attaches a temperature sensor to the signal conditioner and monitors the temperature to detect an abnormality in the signal conditioner (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-232949 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of the on-board communication device described in Patent Document 1, a temperature sensor is required on the signal conditioner side, which is installed at a location away from the on-board unit, which is the main body of the on-board communication device installed inside the vehicle, and temperature information needs to be transmitted to the on-board unit. In addition, installing a temperature sensor increases the size of the signal conditioner.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide an in-vehicle communication device that does not require a temperature sensor on the signal conditioner side and does not increase the size of the signal conditioner. [Means for solving the problem]

[0006] The in-vehicle communication device of the present disclosure includes an in-vehicle device installed inside the vehicle and configured to transmit and receive wireless signals; an antenna for transmitting and receiving the wireless signal between the vehicle and a communication target located away from the vehicle; a signal conditioner that is installed in a position where a temperature environment is different from that of the in-vehicle device and that adjusts an amplitude of the wireless signal between the in-vehicle device and the antenna, The vehicle-mounted device is configured to estimate a temperature of the signal conditioner based on a current supplied to the signal conditioner. [Effects of the Invention]

[0007] According to the in-vehicle communication device of the present disclosure, it is possible to provide an in-vehicle communication device that does not require a temperature sensor on the signal conditioner side and does not increase the size of the signal conditioner. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a vehicle equipped with an on-board communication device according to a first embodiment. [Figure 2] 1 is a block diagram showing a configuration of an in-vehicle communication device according to a first embodiment. [Figure 3] 4 is a flowchart for explaining the operation of the in-vehicle communication device according to the first embodiment. FIG. [Figure 4] 4 is a flowchart for explaining the operation of a temperature estimation unit of the in-vehicle communication device according to the first embodiment. FIG. [Figure 5] 4 is a diagram showing an example of data stored in a data storage unit that stores the relationship between the supply current and the temperature of a signal conditioner of the on-board communication device according to the first embodiment. FIG. [Figure 6] 1 is a diagram showing an example of data stored in a data storage unit that stores the relationship between the temperatures of an on-board unit and a signal conditioner of the on-board communication device according to the first embodiment. [Figure 7] 4 is a diagram showing an image of data stored in a data storage unit that stores the relationship between the temperatures of an on-board unit and a signal conditioner of the on-board communication device according to the first embodiment. FIG. [Figure 8] FIG. 10 is a block diagram showing the configuration of an in-vehicle communication device according to a second embodiment. [Figure 9] FIG. 10 is a flowchart illustrating the operation of the in-vehicle communication device according to the second embodiment. [Figure 10] 10 is a diagram showing an example of data stored in a data storage unit that stores the relationship between the supply current of each of a signal conditioner and an interface device of an in-vehicle communication device according to the second embodiment and the temperature of each device. FIG. [Figure 11] 10 is a diagram showing an image of data in a data storage unit that stores the relationship between the temperatures of the on-board unit, the signal conditioner, and the interface device of the on-board communication device according to the second embodiment. FIG. [Figure 12] 1 is a block diagram showing an example of the configuration of an in-vehicle device according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment 1 FIG. 1 is a schematic diagram of a vehicle equipped with an on-board communication device according to a first embodiment. The following description will be given taking, as an example, an on-board communication device for vehicle-to-vehicle communication, which exchanges wireless signals for vehicle-to-vehicle communication between the vehicle and another vehicle and transmits and receives vehicle information. The on-board communication device 100 includes, as main devices, an on-board unit 1 disposed inside the vehicle, an antenna 3 installed in a location, such as outside the vehicle, that has a different temperature environment from the on-board unit 1, and a signal conditioner 2 disposed near the antenna 3, i.e., in a location that has a different temperature environment from the on-board unit 1, that adjusts the amplitude of the wireless signal to ensure communication with the other vehicle. For vehicle-to-vehicle communication, synchronization between the vehicle and the other vehicle is required, and this is achieved by a highly accurate 1PPS signal obtained by receiving a GNSS (Global Navigation Satellite System) signal 51. For this purpose, a GNSS antenna 20 is provided. The GNSS antenna 20 is usually disposed inside the vehicle. The in-vehicle communication device of the present disclosure is applicable not only to vehicle-to-vehicle communication, but also to communication between a vehicle and a communication target located away from the vehicle, such as so-called road-to-vehicle communication. In communications that do not require synchronization or when synchronization is performed using a signal other than GNSS, the GNSS antenna 20 is not essential.

[0010] FIG. 2 is a block diagram showing the configuration of an in-vehicle communication device 100 according to the first embodiment. The in-vehicle device 1, which is the main component of the in-vehicle communication device 100, has, as its main function, a transceiver unit 11 that transmits and receives V2V (Vehicle to Vehicle) signals, which are wireless signals for vehicle-to-vehicle communication. The V2V signals transmitted from the transceiver unit 11 are transmitted to an antenna 3 via a normal transmission line, and then transmitted from the antenna 3 to other vehicles. In addition, V2V signals received by the antenna 3 from other vehicles are transmitted to the transceiver unit 11. The amplitude of the V2V signals transmitted between the antenna 3 and the transceiver unit 11 is reduced due to losses in the transmission line, and noise and the like are also superimposed on the V2V signals. To ensure more reliable communication, a signal conditioner 2 installed directly below the antenna 3 adjusts the levels (amplitudes) of the transmitted and received V2V signals.

[0011] Power is supplied to the signal conditioner 2 from the on-board device 1. A supply voltage / current acquisition unit 12 acquires the values ​​of the supply voltage and supply current supplied to the signal conditioner 2. A temperature estimation unit 13 estimates the temperature of the signal conditioner 2 based on the acquired supply voltage and supply current, and estimates the temperature of the on-board device 1 from the estimated temperature of the signal conditioner 2. Information required to estimate these temperatures is stored in advance in a data storage unit 14. The temperature estimation unit 13 estimates the temperature of the on-board device 1 from the estimated temperature of the signal conditioner 2 based on information on the current external environment, such as sunlight and temperature, acquired by an external environment acquisition unit 15 and information stored in the data storage unit 14.

[0012] The abnormality determination unit 16 compares the estimated temperature of the vehicle-mounted device 1 estimated by the temperature estimation unit 13 with the actual temperature of the vehicle-mounted device 1 acquired by the vehicle-mounted device temperature acquisition unit 17 from a temperature sensor or the like, and if there is a difference between the two that is greater than a predetermined value, it determines that the signal adjuster 2 is abnormal and sends a signal indicating an abnormality to the transceiver unit 11. The transceiver unit 11 then stops transmitting the V2V signal, and the notification unit 18 notifies the user, such as the driver, of the abnormality by means of a display or sound, etc.

[0013] Next, details of the operation of the in-vehicle communication device according to the first embodiment will be described with reference to the flowcharts of Fig. 3 and Fig. 4. Fig. 3 shows the overall flow of the operation, and Fig. 4 shows the detailed flow of steps ST4 to ST5 in Fig. 3.

[0014] First, when preparations for vehicle movement, such as starting the engine (ST1), are completed, the transmitter / receiver 11 starts transmitting a V2V signal so that inter-vehicle communication becomes possible, and the V2V signal adjusted by the signal conditioner 2 is transmitted from the antenna 3 (ST2). Once the transmitter / receiver 11 starts transmitting the V2V signal, the temperature is estimated according to the following procedure to determine whether or not the signal conditioner 2 is abnormal. First, the supply voltage / current acquisition unit 12 acquires the value of the supply current to the signal conditioner 2 (ST3). The temperature of the signal conditioner 2 is estimated from the acquired supply current value (ST4). Next, the temperature of the in-vehicle device 1 is estimated from the estimated temperature of the signal conditioner 2 (ST5).

[0015] Steps ST4 to ST5 are performed according to the flow shown in Figure 4. Supply voltage / current acquisition unit 12 acquires the value of the supply voltage to signal conditioner 2 (ST41). Meanwhile, data storage unit 14 stores a matrix table as shown in Figure 5, in which the relationship between the value of the supply current to signal conditioner 2 and the temperature of signal conditioner 2 is previously investigated and associated for each supply voltage. Temperature estimation unit 13 acquires a supply current-temperature table corresponding to the acquired supply voltage from the table stored for each supply voltage in data storage unit 14 (ST42), reads the temperature of signal conditioner 2 corresponding to the acquired supply current from the acquired table, and sets that temperature as the estimated temperature of signal conditioner 2 (ST43).

[0016] In the above, the relationship between supply current and temperature is stored for each supply voltage of signal conditioner 2, but the temperature of signal conditioner 2 may also be affected by the amplification gain of signal conditioner 2. In this case, the table of Fig. 5 is stored for each combination of supply voltage and amplification gain.

[0017] Next, the temperature estimation unit 13 estimates the temperature of the on-board device 1 based on the estimated temperature of the signal conditioner 2 (ST5). However, the relationship between the temperatures of the on-board device 1 and the signal conditioner 2 varies depending on external environmental conditions such as air temperature, sunlight (weather, illuminance), average vehicle speed during driving, and driving time. FIG. 6 shows an example of the relationship between the temperatures of the on-board device 1 and the signal conditioner 2 under different external environmental conditions. FIG. 6A is a table showing the relationship between the temperatures of the on-board device 1 and the signal conditioner 2 when the external environmental conditions are [weather: cloudy, temperature: 20°C, illuminance: 30,000 lux, average vehicle speed during driving: 40 km / h, driving time: 30 minutes] (external environmental condition 1). FIG. 6B is a table showing the relationship between the temperatures of the on-board device 1 and the signal conditioner 2 when the external environmental conditions are [weather: sunny, temperature: 35°C, illuminance: 100,000 lux, parked vehicle] (external environmental condition 2). As such, the relationship between the temperatures of the on-board device 1 and the signal conditioner 2 varies depending on the external environmental conditions. Therefore, the relationship between the temperatures of the on-board device 1 and the signal conditioner 2 is investigated and associated in advance for each external environmental condition, and a matrix table such as that shown in Fig. 7 is stored in the data storage unit 14. The external environmental conditions are acquired from the external environment acquisition unit 15 (ST51), a table corresponding to the acquired external environmental condition is acquired from the matrix table stored in the data storage unit 14 (ST52), and the temperature of the on-board device corresponding to the temperature of the signal conditioner 2 estimated in step ST4 (steps ST41 to ST43) is read from the table and used as the estimated temperature of the on-board device (ST53).

[0018] Although there have been reports of methods for estimating the temperature of a signal conditioner using an outside air temperature sensor typically installed in a vehicle, it is expected that the temperature of a signal conditioner is actually significantly affected by factors other than air temperature. For example, the temperature may rise due to sunlight in hot weather, or the antenna outside the vehicle may be affected by wind while driving. Therefore, estimation based on outside air temperature alone is likely to be insufficient in accuracy. As described above, the present disclosure improves the accuracy of temperature estimation by acquiring and classifying multiple external environmental conditions. For example, it is desirable that the external environment factors that affect the temperature of the signal conditioner 2 include at least illuminance (which best reflects the effect of sunlight), temperature, and driving time. Of these, illuminance and temperature can be averaged over a predetermined period of time, such as 10 minutes.

[0019] Next, the in-vehicle device temperature acquisition unit 17 acquires the temperature of the in-vehicle device 1, for example, from a temperature sensor installed in the in-vehicle device 1 (ST6). The abnormality determination unit 16 compares the estimated temperature of the in-vehicle device estimated in step ST5 (ST51 to ST53) with the actual temperature (acquired temperature) of the in-vehicle device 1 acquired by the in-vehicle device temperature acquisition unit 17. If the difference between the estimated temperature and the acquired temperature is greater than a preset value (ST7 Yes), it determines that an abnormality has occurred and outputs an abnormality signal to the transceiver unit 11, which then stops sending the V2V signal (ST8). The abnormality signal is also output to the notification unit 18, which notifies the user of the abnormality. The notification is performed, for example, by displaying the abnormality on a display or by sounding it from a speaker.

[0020] If the difference between the estimated temperature of the vehicle-mounted device 1 and the acquired temperature is less than a preset value, it is determined that there is no abnormality, and the process returns to step ST3, and steps ST3 to ST7 are repeated until vehicle-to-vehicle communication is no longer required, for example, when the engine is turned off.

[0021] In the above, an example has been described in which a matrix table is stored in data storage unit 14, but functions may also be stored instead of tables. For example, the relationship between the supply current and temperature of the signal conditioner shown in FIG. 5 may be stored as a function of signal conditioner temperature Ts=f (supply current) for each parameter, with supply voltage as a parameter. The relationship based on external environmental conditions shown in FIG. 7 may also be stored as a function of on-board device temperature Tc=f (signal conditioner temperature) for each external environmental condition.

[0022] As described above, in the vehicle-mounted communication device according to embodiment 1, without providing a temperature sensor that directly measures the temperature of the signal conditioner 2 installed in a temperature environment different from that of the vehicle-mounted device 1, such as outside the vehicle, the temperature of the signal conditioner 2 is estimated from the current supplied to the signal conditioner 2, the temperature of the vehicle-mounted device 1 is estimated based on the estimated temperature of the signal conditioner, the estimated temperature of the vehicle-mounted device 1 is compared with the actual temperature of the vehicle-mounted device 1 measured by a temperature sensor or the like, and if the difference is large, it is determined that the signal conditioner 2 is abnormal. Therefore, a temperature sensor that directly measures the temperature of the signal conditioner 2 is not required, and the signal conditioner 2 can be made small.

[0023] Embodiment 2 Fig. 8 is a block diagram showing the configuration of an in-vehicle communication device 200 according to embodiment 2, and Fig. 9 is a flow diagram for explaining the operation. The following describes the differences from embodiment 1. As shown in Fig. 8, the in-vehicle device 1 of the in-vehicle communication device 200 according to embodiment 2 is provided with an interface device supply current acquisition unit 19 that acquires the supply current of an interface device installed in a position different from that of the in-vehicle device 1.

[0024] In the in-vehicle communication device 100 according to the first embodiment, the temperature of the signal conditioner 2 is estimated based on the supply current to the signal conditioner 2, and the temperature of the in-vehicle device 1 is estimated based on the estimated temperature of the signal conditioner 2. In the in-vehicle communication device 200 according to the second embodiment, as shown in FIG. 9, the supply current to the signal conditioner 2 is acquired, and the interface device supply current acquisition unit 19 acquires the supply current to an interface device installed in a position different from that of the in-vehicle device 1 (ST30). The data storage unit 14 stores a matrix table as shown in FIG. 10, which correlates the value of the supply current to the signal conditioner 2 and the temperature of the signal conditioner 2, and the value of the supply current to the interface device and the temperature of the interface device, which have been previously investigated for each supply voltage to the signal conditioner 2. Note that, since it is assumed here that the supply voltage to the interface device is a constant value that does not fluctuate, the supply voltage to the interface device is not included as a parameter. The temperature estimation unit 13 obtains a supply current-temperature table corresponding to the obtained supply voltage from a table stored for each supply voltage in the data storage unit 14, reads the temperatures of the signal conditioner 2 and the interface device corresponding to the obtained supply current from the obtained table, and sets these temperatures as the estimated temperature of the signal conditioner 2 and the estimated temperature of the interface device (ST40). The relationship between the temperatures of the on-board unit 1, the signal conditioner 2, and the interface device for each external environmental condition is examined and associated in advance, and a matrix table such as that shown in FIG. 11 is stored in the data storage unit 14. The external environmental conditions are obtained from the external environment acquisition unit 15, and a table corresponding to the obtained external environmental condition is obtained from the matrix table stored in the data storage unit 14. The temperature of the on-board unit corresponding to the temperature of the signal conditioner 2 estimated in step ST40 is read from the table, and set as the estimated temperature of the on-board unit estimated from the estimated temperature of the signal conditioner 2. The temperature of the on-board unit corresponding to the temperature of the interface device estimated in step ST40 is also read, and set as the estimated temperature of the on-board unit estimated from the estimated temperature of the interface device (ST50).

[0025] In step ST6, the temperature of the on-board device is acquired from the on-board device temperature acquisition unit 17. If the difference between the acquired temperature and the estimated temperature of the on-board device estimated from the estimated temperature of the signal conditioner 2 in step ST70 is greater than a preset value (ST70 Yes), the estimated temperature of the on-board device estimated from the interface device is compared with the acquired temperature. If the difference between the estimated temperature and the acquired temperature is equal to or less than the preset value (ST71 No), it is determined that the signal conditioner 2 is abnormal (ST72). If the difference is greater than the preset value (ST71 Yes), it is determined that the on-board device temperature acquisition unit (temperature sensor of the on-board device) 17 is abnormal (ST73). Steps from ST8 onwards are the same as those from ST8 onwards in the first embodiment.

[0026] As described above, in the vehicle-mounted communication device 200 according to the second embodiment, the temperature of the signal conditioner 2 is estimated based on the supply current of the signal conditioner 2, and the temperature of the interface device installed in a different location from the vehicle-mounted device 1 is estimated based on the supply current of the interface device, and the temperature of the vehicle-mounted device 1 is estimated based on the estimated temperatures of the signal conditioner 2 and the interface device, thereby achieving the effect of detecting an abnormality in the vehicle-mounted device temperature acquisition unit (temperature sensor of the vehicle-mounted device).

[0027] As shown in FIG. 12 , the in-vehicle device 1 of the present disclosure includes, for example, a central processing unit (CPU) or other processing device 101, a storage device 102 for exchanging data with the processing device 101, and an input / output interface 103 for inputting and outputting signals between the processing device 101 and the outside. The processing device 101 may include an application-specific integrated circuit (ASIC), an integrated circuit (IC), a digital signal processor (DSP), a field programmable gate array (FPGA), and various signal processing circuits. The storage device 102 may include a random access memory (RAM) configured to read and write data from the processing device 101, and a read-only memory (ROM) configured to read data from the processing device 101. The temperature estimation unit 13, the abnormality determination unit 16, and the like are implemented by the processing device 101 executing a program stored in the storage device 102. The storage device 102 is included in the data storage unit 14. The input / output interface 103 is, for example, an interface for converting signals input from the outside into signals that can be input to the arithmetic processing unit 101, and constitutes the supply voltage / current acquisition unit 12, the external environment acquisition unit 15, the vehicle-mounted device temperature acquisition unit 17, etc.

[0028] Although the present disclosure describes exemplary embodiments, the various features, aspects, and functions described in the embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this specification, including, for example, the modification, addition, or omission of at least one component. [Explanation of symbols]

[0029] 1 on-board unit, 2 signal conditioner, 3 antenna, 17 on-board unit temperature acquisition unit

Claims

1. an on-board device installed inside the vehicle for transmitting and receiving wireless signals; an antenna for transmitting and receiving the wireless signal between the vehicle and a communication target located away from the vehicle; a signal conditioner that is installed in a position where a temperature environment is different from that of the in-vehicle device and that adjusts an amplitude of the wireless signal between the in-vehicle device and the antenna, The vehicle-mounted communication device estimates the temperature of the signal conditioner based on a current supplied to the signal conditioner.

2. The in-vehicle communication device according to claim 1 , wherein the in-vehicle device estimates the temperature of the in-vehicle device from the estimated temperature of the signal conditioner.

3. 3. The vehicle-mounted communication device according to claim 2, wherein the vehicle-mounted device stores signal conditioner temperature vs. on-board device temperature data, which is a relationship between the temperature of the signal conditioner and the temperature of the on-board device, measured in advance for each external environmental condition, in association with the external environmental condition; the vehicle-mounted device reads the relationship between the signal conditioner temperature vs. on-board device temperature corresponding to the current external environmental condition from the stored signal conditioner temperature vs. on-board device temperature data; and estimates the temperature of the on-board device corresponding to the estimated temperature of the signal conditioner from the read relationship between the signal conditioner temperature vs. on-board device temperature.

4. 4. The vehicle-mounted communication device according to claim 3, wherein the external environmental conditions include at least illuminance, temperature, and driving time.

5. 5. The vehicle-mounted communication device according to claim 1, further comprising an on-board device temperature measurement unit that measures the actual temperature of the on-board device, and determines that the signal conditioner is abnormal if the difference between the temperature of the on-board device measured by the on-board device temperature measurement unit and the estimated temperature of the on-board device is greater than a predetermined value.

6. 5. An in-vehicle communication device according to claim 1, wherein the temperature of an interface device installed at a location separate from the in-vehicle device is estimated based on the current supplied to the interface device, and the temperature of the in-vehicle device is estimated from the estimated temperature of the signal conditioner and the estimated temperature of the interface device.

7. an on-board device temperature measurement unit for measuring an actual temperature of the on-board device, and when a difference between the temperature of the on-board device measured by the on-board device temperature measurement unit and the temperature of the on-board device estimated from the estimated temperature of the signal conditioner is larger than a preset value, determining that the signal conditioner is abnormal when a difference between the temperature of the in-vehicle device estimated from the estimated temperature of the interface device and the temperature of the in-vehicle device measured by the in-vehicle device temperature measuring unit is equal to or smaller than a preset value; 7. The in-vehicle communication device according to claim 6, wherein when a difference between the temperature of the in-vehicle device estimated from the estimated temperature of the interface device and the temperature of the in-vehicle device measured by the in-vehicle device temperature measurement unit is greater than a preset value, the in-vehicle device temperature measurement unit is determined to be abnormal.

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