On-vehicle device

Abstract

To enhance safety when vehicles pass through toll gates without requiring complex image processing.SOLUTION: An on-vehicle device 3 includes: a control circuit 4 that is installed in a vehicle, performs toll billing processing by communicating with a roadside unit 2 installed at the toll gate, and executes various controls including those related to billing processing; and an acceleration sensor 13 that detects the vehicle's acceleration and outputs a detection signal Sb corresponding to the detected value. When receiving a communication signal from the roadside unit 2, the control circuit 4 performs a determination process to determine the vehicle's state based on the detection signal Sb, and can execute suppression control to reduce the vehicle's speed depending on the result of the determination process.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an in-vehicle device that is mounted on a vehicle and performs a charging process for a usage fee by communicating with a roadside device installed at a toll gate. [Background technology]

[0002] The ETC system, which enables non-stop toll collection at toll gates on toll roads, i.e., charging of usage fees, is configured by installing a roadside unit at the toll gate and installing an onboard unit in the vehicle that handles the charging of usage fees by wireless communication via the antenna of the roadside unit.

[0003] Patent Documents 1, 2, and 3 disclose techniques for notifying a driver of information relating to the vehicle speed when the vehicle, such as an automobile, approaches a toll gate in an ETC system. ETC is an abbreviation for Electronic Toll Collection System and is a registered trademark. In the following description, the toll gate may be referred to as an ETC gate.

[0004] According to such conventional technology, the driver of a vehicle can easily grasp the vehicle speed when approaching an ETC gate, and based on that, can quickly take appropriate measures such as reducing the vehicle speed to 20 km / h or less.In the following description, the technologies described in Patent Documents 1, 2, and 3 may be referred to as the first conventional technology, the second conventional technology, and the third conventional technology, respectively. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-163232 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-227300 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-252110 Summary of the Invention [Problem to be solved by the invention]

[0006] The first prior art requires complex image processing, and therefore cannot be configured as a simple standalone ETC on-board unit installed in a vehicle. Instead, a camera and an image processing device with relatively large CPU capacity are required in addition to the on-board unit. The second and third prior arts are configured to obtain vehicle speed information from outside the ETC on-board unit via an interface. Note that, in this specification, interface is sometimes abbreviated as I / F. The second and third prior arts have the problem that, because vehicle speed information is obtained via an I / F, the reliability of the data is reduced due to the influence of wiring and noise from external devices, and it is difficult to speed up processing based on vehicle speed information.

[0007] The present invention has been made in consideration of the above circumstances, and its object is to provide an on-board device that can improve safety when a vehicle passes through a toll gate without requiring complex image processing. [Means for solving the problem]

[0008] The vehicle-mounted device described in claim 1 is mounted on a vehicle and performs charging processing for usage fees by communicating with a roadside device (2) installed at a toll gate, and is equipped with a control circuit (4) that executes various controls including control related to the charging processing, and an acceleration sensor (13) that detects the acceleration of the vehicle and outputs a detection signal corresponding to the detected value.

[0009] According to the above configuration, the control circuit can obtain vehicle acceleration information from an acceleration sensor installed in the on-board device, rather than from an external source. Unlike the speed information in the second and third conventional technologies, the acceleration information obtained in this way does not involve an interface or the like, and is therefore not affected by wiring or noise from external devices. This results in high data reliability, and also enables the speed of suppression control, which is a process performed based on the acceleration information.

[0010] Furthermore, since it is clear that there is a certain relationship between acceleration and speed, such as integrating acceleration to obtain speed, it is clear that the above configuration for acquiring acceleration information can perform processing equivalent to that of the conventional technology for acquiring speed information. Furthermore, since the above configuration does not require complex image processing as in the first conventional technology, the above-mentioned functions can be realized with a simple configuration of the on-board device alone. Therefore, the above configuration can improve safety when a vehicle passes through a toll gate without requiring a configuration for complex image processing. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a configuration of an ETC system according to a first embodiment. [Figure 2] FIG. 10 is a diagram showing a first specific example of a series of processes executed by the control circuit according to the first embodiment when the control circuit receives a communication signal from a roadside device. [Figure 3] FIG. 10 is a diagram showing a second specific example of a series of processes executed by the control circuit according to the first embodiment when the control circuit receives a communication signal from a roadside device. [Figure 4] FIG. 10 is a diagram showing a third specific example of a series of processes executed by the control circuit according to the first embodiment when the control circuit receives a communication signal from a roadside device. [Figure 5] FIG. 10 is a diagram showing a fourth specific example of a series of processes executed by the control circuit according to the first embodiment when the control circuit receives a communication signal from a roadside device. [Figure 6]FIG. 10 is a diagram illustrating a configuration of an ETC system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, several embodiments will be described with reference to the drawings. Note that substantially the same components in the respective embodiments will be denoted by the same reference numerals, and the description thereof will be omitted. (First embodiment) The first embodiment will be described below with reference to FIGS.

[0013] As shown in Fig. 1, the ETC system 1 of this embodiment includes a roadside unit 2 and an in-vehicle unit 3, which are installed at the ETC gate of a toll booth. The in-vehicle unit 3 is installed in a vehicle such as an automobile, and is a device that performs a charging process for usage fees by communicating with the roadside unit 2. Specifically, the in-vehicle unit 3 is a device that performs wireless communication with the roadside unit 2 via antennas 3a and 2a, and is installed, for example, on the dashboard of the vehicle or near the driver's seat, and is configured to allow an IC card to be inserted therein.

[0014] The in-vehicle device 3 includes a control circuit 4, a wireless communication unit 5, a device connection unit 6, a memory unit 7, a display unit 8, an input operation unit 9, an audio output unit 10, an IC card control unit 11, a power supply unit 12, an acceleration sensor 13, etc. The control circuit 4 is mainly composed of a microcomputer having a CPU, ROM, RAM, etc., an ASIC, etc., and controls the operation of the in-vehicle device 3 by executing software processing by the CPU running a computer program stored in a non-transitory tangible storage medium, and hardware processing by a dedicated electronic circuit. ASIC is an abbreviation for Application Specific Integrated Circuit. The control circuit 4 performs various controls, including control of the charging process of the ETC system 1.

[0015] The control circuit 4 is connected to a wireless communication unit 5 and an antenna 3a for communicating with the roadside unit 2. The wireless communication unit 5 performs short-range wireless communication using the DSRC system with the roadside unit 2. DSRC stands for Dedicated Short Range Communication. The antenna 3a can take various forms, such as one that is integrally provided on the main body of the vehicle-mounted device 3, or one that is provided as an independent configuration via a wire from the main body of the vehicle-mounted device 3 and attached to the windshield, for example.

[0016] The control circuit 4 is connected to a device connection unit 6, a storage unit 7, a display unit 8, an input operation unit 9, an audio output unit 10, and an IC card control unit 11. The device connection unit 6 is an I / F such as USB or RS-232C. The device connection unit 6 is configured to be connectable to, for example, a navigation device 14 mounted on the vehicle and a vehicle control ECU 15, and by exchanging data, they can mutually utilize information to provide useful information to users. Note that ECU is an abbreviation for Electronic Control Unit. In FIG. 1, the navigation device mounted on the vehicle is referred to as a car navigation system, and the control ECU is referred to as an ECU.

[0017] The control circuit 4 can acquire vehicle speed information Ia, which is information about the vehicle speed, from the navigation device 14 through communication via the device connection unit 6. That is, in this case, the control circuit 4 also functions as a speed acquisition unit that acquires the vehicle speed. The control circuit 4 can transmit a signal Sa to the control ECU 15 through communication via the device connection unit 6. In this case, the control circuit 4 can also be configured to transmit the signal Sa to the control ECU 15 through a dedicated signal line, as shown by the dashed line in FIG. 1. With this configuration, the delay time associated with the transmission of the signal Sa from the control circuit 4 to the control ECU 15 can be significantly reduced compared to a configuration in which the signal Sa is transmitted through communication.

[0018] The control ECU 15 is an ECU that performs various controls related to autonomous driving. The control ECU 15 can perform controls such as prohibiting acceleration of the vehicle, automatically decelerating the vehicle, and automatically applying the brakes based on the signal Sa transmitted from the control circuit 4. The storage unit 7 is a non-volatile storage means such as a flash memory or an EEPROM, and is configured to store pre-registered data such as vehicle information when the storage unit is installed in the vehicle, as well as various data required for billing processing.

[0019] The display unit 8 is, for example, a green LED that lights up while a billing process is being executed and a red LED that lights up when a warning is issued. The control circuit 4 outputs a first lighting instruction signal to the display unit 8 while a billing process is being executed, thereby lighting up the green LED. The control circuit 4 outputs a second lighting instruction signal to the display unit 8 when a warning is issued, thereby lighting up the red LED. The display unit 8 can also be configured as a liquid crystal display unit or the like. The input operation unit 9 accepts operation inputs for various settings and information display via operation buttons, and outputs an operation input signal indicating the accepted operation input to the control circuit 4. The audio output unit 10 is, for example, a speaker or a buzzer. The control circuit 4 outputs an audio output instruction signal to the audio output unit 10, thereby causing the audio output unit 10 to output a predetermined sound.

[0020] When an IC card (not shown) is inserted into a card slot (not shown) and attached, the IC card control unit 11 recognizes the attached IC card, reads out card information recorded on the IC card, and outputs the read-out card information to the control circuit 4. The power supply unit 12 is connected to the vehicle battery via an ACC switch, which is an accessory switch of the key switch. When the accessory switch is turned on, the power supply unit 12 generates a predetermined DC voltage and supplies the generated DC voltage to each unit of the vehicle-mounted device 3 to supply power.

[0021] The acceleration sensor 13 detects the acceleration of the vehicle and outputs a detection signal Sb corresponding to the detected value to the control circuit 4. Various types of acceleration sensors can be used as the acceleration sensor 13, such as piezoelectric, servo, strain gauge, and semiconductor types. In this case, the components provided in the vehicle-mounted device 3, including the control circuit 4 and the acceleration sensor 13, are mounted on the same board. Note that the control circuit 4 and the acceleration sensor 13, and the other components, can also be mounted on different boards.

[0022] The control circuit 4 can obtain the acceleration of the vehicle based on the detection signal Sb output from the acceleration sensor 13. The control circuit 4 can also obtain the vehicle speed at that time by performing calculations such as integrating the acceleration detected in this manner. As described above, the control circuit 4 is configured to obtain the vehicle speed based on the vehicle speed information Ia provided by the navigation device 14. However, due to the influence of communication delays and the like, the vehicle speed information Ia is likely to be older information than the current time, and may not accurately represent the vehicle speed at that time.

[0023] On the other hand, the vehicle acceleration information acquired based on the detection signal Sb of the acceleration sensor 13 has very little delay, and therefore is highly real-time information. Therefore, the control circuit 4 corrects the vehicle speed acquired based on the vehicle speed information Ia using the vehicle acceleration calculated based on the detection signal Sb, thereby estimating the vehicle speed at that time. Specifically, such correction can be performed, for example, as follows. That is, for example, if the vehicle speed information Ia indicates 40 km / h and there is a delay of 1 second, the current vehicle speed can be estimated by integrating the acceleration from 1 second before to the present time with the vehicle speed of 40 km / h 1 second before.

[0024] When the control circuit 4 receives a communication signal from the roadside unit 2, it can determine that the vehicle is approaching an ETC gate. When the control circuit 4 receives a communication signal from the roadside unit 2, that is, when it determines that the vehicle is approaching an ETC gate, it executes a determination process to determine the vehicle state based on the detection signal Sb. In the following description, this determination process may be referred to as a first determination process to distinguish it from another determination process described later. When the control circuit 4 receives a communication signal from the roadside unit 2, that is, when it determines that the vehicle is approaching an ETC gate, it executes a second determination process to determine the vehicle state based on the vehicle speed acquired by its function as a speed acquisition unit.

[0025] The control circuit 4 can execute suppression control, which is control for suppressing the vehicle speed, depending on either or both of the results of the first determination process and the second determination process. The first determination process and the second determination process determine whether the state of the vehicle when entering the ETC gate is one that may pose a safety problem, and can specifically be the following process. That is, in the first determination process, the control circuit 4 determines whether the acceleration of the vehicle has exceeded a predetermined threshold acceleration based on the detection signal Sb.

[0026] The threshold acceleration can be set to a predetermined value greater than 0, for example. In the second determination process, the control circuit 4 determines whether the acquired vehicle speed exceeds a predetermined threshold speed. The threshold speed can be set to, for example, 20 km / h, which is a standard speed considered safe when entering an ETC gate, 10 km / h, which is a lower but even safer speed, or 60 km / h, which is a higher upper limit speed that ensures safety.

[0027] The suppression control is a control for increasing the safety of the vehicle when entering the ETC gate. Specifically, the suppression control can be, for example, any one of the following controls (a) to (e) or a combination of two or more of them. (a) Control to perform a notification operation to notify the driver of the current vehicle speed using at least one of a display by the display unit 8 and a sound by the sound output unit 10. (b) Control to perform a notification operation to urge the driver to reduce speed or acceleration using at least one of a display by the display unit 8 and a sound by the sound output unit 10. (c) Control performed by the control ECU 15 to prohibit acceleration of the vehicle. (d) Control performed by the control ECU 15 to automatically decelerate the vehicle. (e) Control performed by the control ECU 15 to automatically activate the brakes.

[0028] The control circuit 4 can execute suppression control only in accordance with the result of the first determination process. Specifically, the control circuit 4 can execute suppression control when the result of the first determination process determines that the vehicle acceleration exceeds a threshold acceleration. In other words, the control circuit 4 can execute suppression control when it determines that a certain degree of acceleration is occurring when the vehicle approaches the ETC gate.

[0029] The control circuit 4 can execute suppression control only in accordance with the result of the second determination process. Specifically, the control circuit 4 can execute suppression control when the result of the second determination process determines that the vehicle speed exceeds the threshold speed. In other words, the control circuit 4 can execute suppression control when it determines that the vehicle is traveling at a certain speed when approaching the ETC gate. The control circuit 4 can execute suppression control in accordance with the result of the first determination process and the result of the second determination process.

[0030] Specifically, when the result of the second determination process indicates that the vehicle speed is equal to or lower than a threshold speed, such as 20 km / h, the control circuit 4 can prevent the suppression control from being executed regardless of whether the first determination process has been executed or the result of the first determination process. In other words, when the control circuit 4 determines that the vehicle speed is sufficiently safe when the vehicle approaches an ETC gate, it can prevent the suppression control from being executed regardless of whether the vehicle is accelerating. Furthermore, when the result of the second determination process indicates that the vehicle speed exceeds a relatively low first threshold speed, such as 20 km / h, but is equal to or lower than a relatively high second threshold speed, such as 60 km / h, or when the result of the first determination process indicates that the vehicle acceleration is equal to or lower than a threshold acceleration, the control circuit 4 can prevent the suppression control from being executed.

[0031] The following describes several specific examples of a series of processes that the control circuit 4 of the vehicle-mounted device 3 configured as described above executes when it receives a communication signal from the roadside device 2. In the following description, the communication signal from the roadside device 2 may be referred to as an ETC signal. In this case, the control circuit 4 communicates with the navigation device 14 at a predetermined timing to acquire vehicle speed information Ia.

[0032] [1] First example In the first specific example, the control circuit 4 executes suppression control only in accordance with the result of the first determination process. In this case, the control circuit 4 executes a series of processes as shown in FIG. 2 at a predetermined timing.

[0033] First, in step S101, it is determined whether or not an ETC signal has been received. If an ETC signal has not been received, step S101 becomes "NO" and the same step is repeatedly executed. On the other hand, if an ETC signal has been received, step S101 becomes "YES" and the process proceeds to step S102. Step S102 corresponds to the first determination process. In step S102, it is determined whether or not the acceleration of the vehicle has exceeded a threshold acceleration, in other words, whether or not acceleration has been detected.

[0034] If acceleration is not detected, step S102 results in "NO" and the process returns to step S101. On the other hand, if acceleration is detected, step S102 results in "YES" and the process proceeds to step S103. In step S103, suppression control such as slowing down acceleration, reducing speed, and notifying the driver is performed. After step S103 is performed, this series of processes ends.

[0035] [2] Second specific example In the second specific example, the control circuit 4 executes suppression control only in response to the result of the second determination process. In this case, the control circuit 4 executes a series of processes as shown in FIG. 3 at a predetermined timing. First, in step S201, it is determined whether or not an ETC signal has been received. If an ETC signal has not been received, the result in step S201 becomes "NO," and the same step is executed repeatedly.

[0036] On the other hand, if an ETC signal has been received, the result in step S201 becomes "YES" and the process proceeds to step S202. In step S202, the vehicle speed acquired based on the vehicle speed information Ia is corrected using the vehicle acceleration determined based on the detection signal Sb. In subsequent processing, the vehicle speed after such correction is used. After step S202 is executed, the process proceeds to step S203.

[0037] Step S203 is a process corresponding to the second determination process. In step S203, it is determined whether the vehicle speed exceeds a threshold speed, specifically, whether the vehicle speed exceeds 20 km / h. If the vehicle speed is 20 km / h or less, step S203 results in "NO" and the process returns to step S201. On the other hand, if the vehicle speed exceeds 20 km / h, step S203 results in "YES" and the process proceeds to step S204. In step S204, suppression control such as slowing down acceleration, reducing speed, or notifying the driver is performed. After step S204 is performed, this series of processes ends.

[0038] [3] Third Specific Example In the third specific example, the control circuit 4 executes suppression control in accordance with the results of the first determination process and the second determination process. In this case, the control circuit 4 executes a series of processes as shown in FIG. 4 at predetermined timing. First, in step S301, it is determined whether or not an ETC signal has been received. If an ETC signal has not been received, the result in step S301 becomes "NO," and the same step is executed repeatedly.

[0039] On the other hand, if an ETC signal has been received, the result in step S301 becomes "YES" and the process proceeds to step S302. In step S302, the vehicle speed acquired based on the vehicle speed information Ia is corrected using the vehicle acceleration determined based on the detection signal Sb. In subsequent processing, the vehicle speed after such correction is used. After step S302 is executed, the process proceeds to step S303.

[0040] Step S303 is a process corresponding to the second determination process. In step S303, it is determined whether the vehicle speed has exceeded a threshold speed, specifically, whether the vehicle speed has exceeded 20 km / h. If the vehicle speed is 20 km / h or less, step S303 results in "NO" and the process returns to step S301. On the other hand, if the vehicle speed exceeds 20 km / h, step S303 results in "YES" and the process proceeds to step S304. Step S304 is a process corresponding to the first determination process. In step S304, it is determined whether the vehicle acceleration has exceeded a threshold acceleration, in other words, whether acceleration has been detected.

[0041] If acceleration is not detected, step S304 returns "NO" and the process returns to step S301. On the other hand, if acceleration is detected, step S304 returns "YES" and the process proceeds to step S305. In step S305, suppression control such as slowing down acceleration, reducing speed, and notifying the driver is performed. After step S305 is performed, this series of processes ends.

[0042] [4] Fourth Specific Example In the fourth specific example, the control circuit 4 executes suppression control in accordance with the results of the first determination process and the second determination process. In this case, the control circuit 4 executes a series of processes as shown in FIG. 5 at predetermined timing. First, in step S401, it is determined whether or not an ETC signal has been received. If an ETC signal has not been received, the result in step S401 becomes "NO," and the same step is executed repeatedly.

[0043] On the other hand, if an ETC signal has been received, the result in step S401 becomes "YES" and the process proceeds to step S402. In step S402, the vehicle speed acquired based on the vehicle speed information Ia is corrected using the vehicle acceleration determined based on the detection signal Sb. In the subsequent processes, the vehicle speed after such correction is used. After step S402 is executed, the process proceeds to step S403.

[0044] Step S403 is a process corresponding to the second determination process. In step S403, it is determined whether the vehicle speed has exceeded a first threshold speed, specifically, whether the vehicle speed has exceeded 20 km / h. If the vehicle speed is 20 km / h or less, the result in step S403 is "NO" and the process returns to step S401. On the other hand, if the vehicle speed exceeds 20 km / h, the result in step S403 is "YES" and the process proceeds to step S404.

[0045] Step S404 is a process corresponding to the second determination process. In step S404, it is determined whether the vehicle speed exceeds a second threshold speed, specifically, whether the vehicle speed exceeds 60 km / h. If the vehicle speed exceeds 60 km / h, the result in step S404 is "YES," and step S405 is skipped and the process proceeds to step S406. On the other hand, if the vehicle speed is 60 km / h or less, the result in step S404 is "NO," and the process proceeds to step S405.

[0046] Step S405 is a process corresponding to the first determination process. In step S405, it is determined whether the acceleration of the vehicle has exceeded a threshold acceleration, in other words, whether acceleration has been detected. If acceleration has not been detected, step S405 results in "NO" and the process returns to step S401. On the other hand, if acceleration has been detected, step S405 results in "YES" and the process proceeds to step S406. In step S406, suppression control such as slowing down acceleration, reducing speed, or notifying the driver is performed. After step S406 is performed, this series of processes ends.

[0047] According to the present embodiment described above, the following effects can be obtained. According to the in-vehicle device 3 configured as described above, the control circuit 4 can obtain information on the acceleration of the vehicle not from a source external to the in-vehicle device 3 but from the acceleration sensor 13 provided in the same in-vehicle device 3. Unlike the speed information in the second and third conventional technologies, the acceleration information obtained in this way does not involve an I / F or the like and is therefore not affected by wiring or noise from external devices, resulting in high data reliability and enabling the speed of suppression control, which is a process performed based on the acceleration information.

[0048] Since it is clear that there is a certain relationship between acceleration and speed, such as integrating acceleration to obtain speed, it is clear that the above-described configuration for acquiring acceleration information can perform processing equivalent to that of the prior art for acquiring speed information. Furthermore, since the above-described configuration does not require complex image processing as in the first prior art, the above-described functions can be realized with a simple configuration of the on-board device 3 alone. Therefore, this embodiment has the effect of improving safety when a vehicle passes through an ETC gate without requiring a configuration for complex image processing.

[0049] In this case, the control circuit 4 and the acceleration sensor 13 are mounted on the same board. This configuration further reduces the influence of noise superimposed on the detection signal Sb sent from the acceleration sensor 13 to the control circuit 4, and further shortens the delay in transmitting the detection signal Sb, thereby further improving the reliability of the data and enabling the suppression control to be performed more quickly.

[0050] In the above configuration, when the control circuit 4 determines that the vehicle is approaching an ETC gate, it executes a first determination process to determine the state of the vehicle based on the detection signal Sb, and can execute suppression control if the first determination process determines that the vehicle's acceleration exceeds a threshold acceleration. The information on the vehicle's acceleration acquired based on the detection signal Sb of the acceleration sensor 13 is highly real-time information. Therefore, by doing so, it is possible to quickly execute suppression control, further improving the safety of the vehicle when entering an ETC gate.

[0051] In the above configuration, when the control circuit 4 determines that the vehicle is approaching an ETC gate, it executes a second determination process to determine the vehicle state based on the vehicle speed acquired by its function as a speed acquisition unit. If the second determination process determines that the vehicle speed exceeds a threshold speed, it can execute suppression control. This allows processing equivalent to that of the prior art to be performed when the vehicle approaches an ETC gate. Note that in this case, the control circuit 4 is configured to acquire the vehicle speed based on vehicle speed information Ia provided by the navigation device 14. However, due to factors such as communication delays, the vehicle speed information Ia is likely to be older than the current information and may not accurately represent the vehicle speed at that time.

[0052] Therefore, the control circuit 4 corrects the vehicle speed acquired based on the vehicle speed information Ia using the vehicle acceleration determined based on the detection signal Sb to estimate the vehicle speed at that time. In this way, the real-timeness of the vehicle speed information used in the second determination process is improved, and as a result, it becomes possible to perform suppression control based on actual measurements, further improving the safety of the vehicle when entering the ETC gate.

[0053] When the control circuit 4 determines that the vehicle is approaching an ETC gate, it can execute suppression control in accordance with the results of the first and second determination processes. In this way, it is possible to realize detailed processing that combines determination based on acceleration and determination based on speed in various ways, such as the third specific example shown in Figure 4 and the fourth specific example shown in Figure 5, thereby improving user convenience.

[0054] For example, if the judgment is based solely on acceleration, even if the vehicle is entering the ETC gate at a sufficiently safe speed, there is a possibility that suppression control will be implemented if the vehicle accelerates slightly, which may result in unnecessary reduction of speed and cause inconvenience to following vehicles.In contrast, according to the third specific example, if the vehicle speed is a sufficiently safe speed such as 20 km / h, even if acceleration of the vehicle is detected, suppression control will not be implemented, thereby eliminating the problem of unnecessary reduction of speed.

[0055] (Second embodiment) The second embodiment will be described below with reference to FIG. As shown in Fig. 6, an ETC system 21 of this embodiment differs from the ETC system 1 of the first embodiment shown in Fig. 1 in that it includes an on-board unit 22 instead of the on-board unit 3. The on-board unit 22 includes a GPS receiver 23 and a processing unit 24 in addition to the same configuration as the on-board unit 3. GPS is an abbreviation for Global Positioning System. In this case, only the vehicle control ECU 15 is connected to the device connection unit 6, and the navigation device 14 is not connected.

[0056] The GPS receiver 23 receives satellite signals transmitted from GPS satellites orbiting the sky via the antenna 3a or a separately provided dedicated antenna (not shown). The arithmetic processing unit 24 is mainly composed of a microcomputer having a CPU, ROM, RAM, etc., an ASIC, etc., and performs various controls by executing software processing by the CPU running a computer program stored in a non-transitory physical storage medium, and hardware processing by dedicated electronic circuits.

[0057] The calculation processing unit 24 can calculate and determine the vehicle's traveling position, i.e., the vehicle's current position and vehicle speed, based on the signal received by the GPS receiver 23. The calculation processing unit 24 outputs vehicle speed information Ib, which is information on the vehicle speed, to the control circuit 4. In this way, unlike the in-vehicle device 3, the in-vehicle device 22 is configured to be able to acquire vehicle speed information by itself. The control circuit 4 of this embodiment can use the vehicle speed information Ib to perform various controls equivalent to those performed using the vehicle speed information Ia in the first embodiment.

[0058] According to the present embodiment described above, the control circuit 4 can also execute the same control as in the first embodiment when the vehicle approaches an ETC gate, and therefore, similar to the first embodiment, it is possible to obtain the effect of improving safety when the vehicle passes through the ETC gate without requiring a configuration for complex image processing. Furthermore, according to the present embodiment, since the vehicle speed information can be obtained by the on-board device 22 alone, it is possible to obtain the effect of enabling control using the vehicle speed information even when the vehicle is not equipped with a navigation device 14.

[0059] (Other embodiments) The present invention is not limited to the embodiments described above and illustrated in the drawings, but can be modified, combined, or expanded as desired without departing from the spirit of the invention. The numerical values ​​and the like shown in the above embodiments are examples and are not limited to these.

[0060] The present invention is not limited to the on-board units 3, 22 used in the ETC systems 1, 21 described in the above embodiments, but can be applied to all on-board units that are mounted on vehicles and perform charging processes for usage fees by communicating with roadside units installed at toll gates.

[0061] The control circuit 4 was previously configured to perform the determination process and suppression control when it received a communication signal from the roadside unit 2, but the control circuit 4 may be configured to perform the determination process and suppression control when it receives a communication signal from the roadside unit 2. In other words, the control circuit 4 can perform the determination process and suppression control at the time when it receives a communication signal from the roadside unit 2 or at any time after it receives the communication signal.

[0062] Specifically, the control circuit 4 can execute the determination process and the suppression control at the following timings. - The timing when the communication signal from roadside unit 2 was first received The timing when it is determined that communication with roadside unit 2, i.e., ETC communication, has failed Incidentally, ETC communication failures are expected to occur when the billing process is not completed within a predetermined time, when communication does not complete normally due to a malfunction of the roadside unit 2 or the vehicle-mounted unit 3, or when card information cannot be read normally due to a malfunction of the IC card or when the IC card is not inserted.

[0063] Furthermore, if the control circuit 4 fails to receive a communication signal multiple times, it may perform the determination process and suppression control when the count value of the number of times reaches a specified value. Furthermore, if ETC communication is completed normally after receiving a communication signal from the roadside unit 2, that is, if the billing process is completed normally, the control circuit 4 may not perform the determination process and thus the suppression control. This is because if the billing process is completed normally, there is little chance of a safety problem occurring when the vehicle passes through the ETC gate.

[0064] In the specific examples of suppression control, (a) and (b) are configured to perform the notification operation using at least one of a display by the display unit 8 and a sound by the sound output unit 10, but instead, the notification operation can be performed using at least one of a display and a sound by the navigation device 14. The control circuit 4 and the acceleration sensor 13 may be mounted on different substrates.

[0065] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0066] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. [Explanation of symbols]

[0067] 1, 21...ETC system, 2...roadside unit, 3, 22...onboard unit, 4...control circuit, 13...acceleration sensor.

Claims

1. An on-board device that is mounted on a vehicle and performs charging processing for usage fees by communicating with a roadside device (2) installed at a toll gate, a control circuit (4) for executing various controls including controls related to the billing process; an acceleration sensor (13) that detects the acceleration of the vehicle and outputs a detection signal corresponding to the detected value; An on-board device comprising:

2. The control circuit When receiving a communication signal from the roadside device, a determination process is performed to determine the state of the vehicle based on the detection signal; 2. The vehicle-mounted device according to claim 1, wherein the vehicle-mounted device is capable of executing a suppression control, which is a control for suppressing the speed of the vehicle, depending on the result of the determination process.

3. 3. The vehicle-mounted device according to claim 1, wherein the control circuit and the acceleration sensor are mounted on the same substrate.

4. The control circuit In the determination process, it is determined whether or not the acceleration of the vehicle exceeds a predetermined threshold acceleration based on the detection signal; 3. The vehicle-mounted device according to claim 1, wherein the suppression control is executed when it is determined that the acceleration of the vehicle exceeds the threshold acceleration as a result of the determination process.

5. Further, a speed acquisition unit (4) for acquiring the speed of the vehicle is provided, If the determination process is a first determination process, when the control circuit receives the communication signal from the roadside device, it executes a second determination process to determine a state of the vehicle based on the speed of the vehicle acquired by the speed acquisition unit; 5. The vehicle-mounted device according to claim 4, wherein the suppression control is executed in accordance with results of the first determination process and the second determination process.

6. The control circuit In the second determination process, it is determined whether or not the speed of the vehicle acquired by the speed acquisition unit exceeds a predetermined threshold speed; 6. The vehicle-mounted device according to claim 5, wherein when the result of the second determination process indicates that the speed of the vehicle is equal to or lower than the threshold speed, the suppression control is not executed regardless of whether the first determination process has been executed or not and the result thereof.

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