JP4983454B2 - Road-to-vehicle communication system, optical beacon, in-vehicle device, and vehicle - Google Patents

Description

  The present invention relates to a road-to-vehicle communication system that performs bidirectional communication using an optical signal between an optical beacon installed on a road side and an in-vehicle device mounted on a vehicle, and light that can be used in the road-to-vehicle communication system. The present invention relates to a beacon, an in-vehicle device, and a vehicle.

As a traffic information service using a road-vehicle communication system, so-called VICS (Vehicle Information and Communication System) using an optical beacon, a radio beacon, or FM multiplex broadcasting has already been developed. Among these, the optical beacon employs optical communication using near infrared rays as a communication medium, and enables two-way communication with the in-vehicle device.
Specifically, uplink information including travel time information between beacons held by the vehicle is transmitted from the in-vehicle device to the optical beacon on the infrastructure side, and conversely, traffic jam information, section travel time information, event regulation information, and lanes Downlink information including notification information and the like is transmitted from the optical beacon to the vehicle-mounted device (see, for example, Patent Document 1).

The optical beacon includes a light emitter / receiver that performs bidirectional communication with an in-vehicle device. The light emitter / receiver includes a light emitting diode (LED) that transmits downlink information and uplink information from the in-vehicle device. And a photo sensor for receiving light.
For example, as shown in FIG. 10, in the light projector / receiver (projector / receiver) 108 of the optical beacon 104, the communication area A is set on the upstream side from immediately below. According to the “near-infrared interface standard” of the optical beacon (optical vehicle sensor) 104, the uplink area UA overlaps with the upstream part (right part in FIG. 10) of the downlink area DA in the vehicle traveling direction. The upstream ends of the downlink area DA and the uplink area UA are made to coincide with each other. In practice, the currently set upstream end of the downlink area DA is often set upstream (for example, c ′ in FIG. 10) from the upstream end c of the uplink area UA.

Therefore, the vehicle traveling direction length of the downlink area DA matches the same direction length of the entire communication area A. In addition, according to the above standard, in the case of the optical beacon 104 for general roads, the downstream end a of the downlink area DA is located 1.0 to 1.3 m upstream immediately below the projector / receiver 108 and The distance from the downstream end a of the link area DA to the downstream end b of the uplink area UA is defined as 2.1 m, and the distance from the downstream end b of the uplink area UA to the upstream end c of the area UA is 1.6 m. It is prescribed. Accordingly, in this case, the total length of the communication area A in the vehicle traveling direction is 3.7 m.
JP 2005-268925 A

In the road-to-vehicle communication system, the following communication is performed between the optical beacon 104 and the vehicle-mounted device 102. First, the optical beacon 104 first always transmits the first downlink information including the lane notification information (no vehicle ID) to the downlink area DA of the road at a predetermined transmission cycle.
When the vehicle enters the downlink area DA and the projector / receiver (vehicle-mounted head) of the vehicle-mounted device 102 mounted on the vehicle receives the first downlink information, the vehicle-mounted device 102 receives the own vehicle. Transmission of uplink information including lane notification information storing the ID is started.
Then, when the projector / receiver 108 of the optical beacon 104 receives the uplink information, the optical beacon 104 performs downlink switching, and includes a second lane notification information having the vehicle ID with respect to the in-vehicle device 102. Start sending downlink information. This second downlink information is repeatedly transmitted as much as possible within a predetermined time and is received by the in-vehicle device 102.

  By such a road-to-vehicle communication system using an optical beacon, for example, a specific position in the communication area A (for example, the upstream end in the vehicle traveling direction) is regarded as the position of the vehicle (onboard unit 102), and the downstream from the specific position. The “distance information” up to the stop line P0 as the predetermined position on the side is included in the second downlink information, and the in-vehicle device 102 that has received this distance information uses the distance information to use the stop line P0. In some cases, the vehicle is braked so that it is forcibly stopped before the vehicle is stopped, or the driver is instructed to stop or decelerate to provide safe driving assistance to the driver (for example, a special feature proposed by the applicant of the present application). Application No. 2006-121692 and Japanese Patent Application No. 2006-121700).

However, when such safe driving support is performed, there are the following problems.
Currently, the communication area A of the optical beacon 104 that is actually operated, particularly the uplink area UA, receives the uplink information from the in-vehicle device 102 more reliably. For example, as shown by a virtual line in FIG. In many cases, the area is considerably wider than the official area defined by the standard (for example, an area indicated by Δdb′c ′). Similarly, the downlink area DA is often set wider than the standard area.
Thus, if the communication area A is wider than the official area, the difference between the specific position in the communication area A that is the starting point of the “distance information” and the actual position when the vehicle receives the distance information Is likely to increase, and the accuracy of the distance information decreases. For this reason, the accuracy of the safe driving support using the distance information is similarly reduced. For example, although the vehicle is braked so as to stop before the stop line 40 by the safe driving support function, A situation may occur in which the vehicle stops after the stop line 40 is exceeded.

  The present invention has been made in view of such circumstances, and allows the vehicle-mounted device to recognize an accurate distance to a predetermined position regardless of whether the uplink region is wide or narrow in the vehicle traveling direction. An object of the present invention is to provide a road-to-vehicle communication system, an optical beacon, an in-vehicle device, and a vehicle that can accurately perform driving support.

In order to achieve the above object, the present invention includes a projector / receiver that sets a communication area including an uplink area capable of receiving uplink information and a downlink area capable of transmitting downlink information within a predetermined range of the road. A road-to-vehicle communication system comprising: an optical beacon; and an in-vehicle device that is mounted on a vehicle and transmits / receives the uplink information and the downlink information to / from the projector / receiver in the communication area. The light emitter / receiver includes a light receiving unit having a light receiving surface for receiving the uplink information, and the light receiving unit sets the uplink region so as to project the light receiving surface onto the road, The light receiving position information on the light receiving position at which the uplink information is received on the light receiving surface is output, and the light beacon is received by the light receiving unit. Based on the received light receiving position information, the on-vehicle device generates position information indicating the transmission position at which the on-vehicle device transmits the uplink information in the uplink region, and the downlink information including the on-vehicle device position information. The vehicle-mounted device position information includes distance information regarding the distance from the transmission position to a predetermined position downstream thereof, and from the upstream end of the uplink region. The distance information includes first distance information about a distance to the predetermined position and second distance information about a distance from the transmission position to the upstream end of the uplink region, as the distance information. Yes.

  According to the road-to-vehicle communication system and the optical beacon configured as described above, the light receiving unit of the projector / receiver sets the uplink region so that the light receiving surface is projected onto the road, and the light receiving unit outputs Since the vehicle-mounted device position information indicating the transmission position is generated based on the received light-receiving position information and the control unit that transmits the downlink information including the vehicle-mounted device position information to the projector / receiver, the optical beacon is Regardless of whether the uplink area is wide or narrow, it is possible to recognize the transmission position at which the in-vehicle device has transmitted the uplink information in the uplink region, and to make the in-vehicle device recognize the transmission position.

Further, the vehicle-mounted device location information, because it contains the distance information on the distance to a predetermined position on the downstream side from the transmission position, it is possible to know the exact distance to the predetermined position in the vehicle device, safe driving Support can be performed with high accuracy.

  The distance information included in the downlink information may be the distance itself from the transmission position to a predetermined position downstream thereof, or the first distance information about the distance from the upstream end of the uplink region to the predetermined position; It is good also as 2nd distance information about the distance from the said transmission position to the upstream end of an uplink area | region.

  In the latter case, the in-vehicle device preferably includes a distance recognition unit that obtains a distance from the transmission position to the predetermined position from the first distance information and the second distance information.

  In either case, in the uplink region, the distance from the position where the in-vehicle device transmits the uplink information to the predetermined position downstream thereof can be accurately recognized.

Further, in the road-to-vehicle communication system and the optical beacon, the control unit divides the light-receiving surface into a plurality of light-receiving regions arranged in a direction corresponding to a vehicle traveling direction based on the light-receiving position information. The link area is divided into a plurality of divided areas arranged in the vehicle traveling direction, and the division corresponding to the identified light receiving area is determined by identifying which of the plurality of light receiving areas has received light based on the light receiving position information. The vehicle-mounted device position information including distance information related to the distance from the position of the region to a predetermined position on the downstream side may be generated.
In this case, the control unit can selectively acquire the distance information by preparing in advance distance information regarding the distance from the position of the divided area to the predetermined position for each of the plurality of divided areas.

It is preferable that the in-vehicle device has a distance recognition unit that recognizes a distance to the predetermined position based on the predetermined downlink information. In addition, the vehicle-mounted device is a signal information receiving unit that receives signal information related to a display schedule of a traffic light set downstream in the vehicle traveling direction, and support that performs control related to driving support based on the signal information and the distance information It is preferable to have a control unit.
In this case, for example, from the distance information about the distance to the stop line position in front of the traffic light and the signal information about the light color of the traffic light, what is the color of the traffic light when the vehicle arrives at the stop line It is possible to predict driving and perform driving support based on this prediction.

The assistance control unit can perform control for braking the vehicle as driving assistance. Thus, for example, when the signal light color is predicted to be red or yellow when the vehicle arrives at the stop line, the vehicle can be stopped at the stop line.
Moreover, it is preferable that a support control part has a function which produces | generates the alerting | reporting information with respect to the passenger of a vehicle as driving assistance. Accordingly, for example, when the signal light color is predicted to be red or yellow when the vehicle arrives at the stop line, the passenger can be recognized that the vehicle needs to be stopped at the stop line.

  According to the present invention, an accurate distance to a predetermined position can be recognized in an in-vehicle device regardless of whether the uplink region is wide or narrow in the vehicle traveling direction, and safe driving support for a driver can be accurately performed.

[First embodiment]
[Overall system configuration]
FIG. 1 is a block diagram showing the overall configuration of the road-vehicle communication system according to the first embodiment.
As shown in FIG. 1, the road-to-vehicle communication system includes an infrastructure-side traffic control system 1 and an in-vehicle device 2 mounted on each vehicle C traveling on a road R.
The traffic control system 1 includes a central device 3 provided in a control room, and a large number of optical beacons (optical vehicle detectors) 4 installed at various locations on the road R. The optical beacon 4 performs bidirectional communication with the in-vehicle device 2 by optical communication using near infrared rays as a communication medium. The central device 3 is provided in the traffic control room.

[Configuration of optical beacon]
The optical beacon 4 includes a communication unit 6 that is a communication interface connected to the central apparatus 3 via a communication line 5 such as a telephone line, a beacon controller 7 to which the communication unit 6 is connected, and the beacon controller 7. And a plurality of (four in the illustrated example) projector / receiver 8 connected to the sensor interface.
FIG. 2 is a plan view of the optical beacon 4. As shown in FIG. 2, the optical beacon 4 of this embodiment is installed on a road R having a plurality of lanes R1 to R4 (four in the illustrated example) in the same direction, and corresponds to each lane R1 to R4. The plurality of light emitters / receivers 8 are provided.
Each projector / receiver 8 is attached to an erection bar 10 installed horizontally on the road R side from a column 9 erected on the side of the road, and is disposed immediately above each lane R1 to R4 of the road R.

  The beacon controller 7 has a function as a control unit that collectively controls the light emitter / receiver 8, and is installed on the column 9. The beacon controller 7 includes a programmable microcomputer having a CPU, a memory (RAM), and a storage device (ROM). The beacon controller 7 includes a bidirectional communication with the central device 3 through the communication unit 6 (FIG. 1), and a projector / receiver 8. It has a function of performing road-to-vehicle communication with the vehicle-mounted device 2 and a function as a control unit that generates vehicle-mounted device position information described later. Note that these functions of the beacon controller 7 will be described later.

Each projector / receiver 8 is configured by housing a light emitting diode (LED) 11 and a light receiving unit 12 in a housing (see FIG. 3). Among these, LED11 light-emits the downlink information which consists of near infrared rays to the communication area A mentioned later, and the light-receiving part 12 light-receives the uplink information which consists of near infrared rays from the vehicle equipment 2. FIG.
The LED 11 of each light emitter / receiver 8 emits near infrared rays toward the upstream side in the vehicle traveling direction from directly below each lane R1 to R4, thereby performing road-to-vehicle communication with the in-vehicle device 2. A communication area A is set on the upstream side of the light emitter / receiver 8.

[About communication area]
FIG. 3 is a side view showing the communication area A of the optical beacon 4.
As shown in FIG. 3, the communication area A of the optical beacon 4 is a downlink area (see FIG. 4) in which the in-vehicle head 27 (see FIG. 4), which is a projector / receiver of the in-vehicle device 2 described later, can receive downlink information. 3 in which the solid line hatching is provided) DA and an uplink area in which the light emitter / receiver 8 of the optical beacon 4 can receive (receive light) the uplink information from the in-vehicle head 27 (broken line hatching in FIG. 3). Provided area) UA.

  The downlink area DA is set to a range indicated by Δdac with the light projecting / receiving position d of the light projecting / receiving device 8 and the positions a and c on the road R as apexes. The uplink area UA is set in the range indicated by Δdbc with the position d and the positions b and c on the road R as vertices. Therefore, the upstream end c of the downlink area DA and the uplink area UA coincide with each other, and the uplink area UA overlaps with the upstream portion (right side portion in FIG. 3) of the downlink area DA in the vehicle traveling direction. Further, the vehicle traveling direction length of the downlink area DA coincides with the same direction length of the entire communication area A.

  According to the “near infrared interface standard” of the optical beacon (optical vehicle sensor) 4, the formal area dimensions of the downlink area DA and the uplink area UA are defined. In this rule, in the case of an optical beacon 4 for a general road, the downstream end a of the downlink area DA is located 1.0 to 1.3 m upstream immediately below the light emitter / receiver 8, and the downlink area DA The distance from the downstream end a to the downstream end b of the uplink area UA is defined as 2.1 m. Further, the distance from the downstream end b of the uplink area UA to the upstream end c of the area UA is defined as 1.6 m. Therefore, the total length (the length between ac) of the official communication area A in the vehicle traveling direction is 3.7 m. However, the vehicle traveling direction lengths of the areas DA and UA are not limited to the above numerical values.

[Configuration of the light receiving section of the emitter / receiver]
FIG. 4A is a side view showing a geometric positional relationship between the light receiving unit 12 and the uplink area UA set on the road R. FIG.
As shown in FIG. 4A, the light receiving unit 12 of the light projecting / receiving device 8 includes a light receiving element 14 mounted on a substrate 13 disposed inside the light projecting / receiving device 8 and a predetermined amount with respect to the light receiving element 14. And a condensing lens 15 arranged opposite to each other.
The light receiving element 14 is formed of a photodiode chip or the like. When the uplink information that has passed through the condenser lens 15 is received by the light receiving surface 14a, the information contained in the uplink information is output as an electrical signal by photoelectric conversion.

The condensing lens 15 of the light receiving unit 12 is set so that the focal point FP is positioned obliquely below the condensing lens 15, and uplink information as infrared light transmitted from the in-vehicle device 2 passes. The uplink information is condensed and refracted so as to irradiate perpendicularly to the light receiving surface 14a of the light receiving element 14. The light receiving element 14 receives the uplink information that passes through the condenser lens 15 and is irradiated on the light receiving surface 14a. That is, the uplink area UA in which the light receiving element 14 can receive the uplink information is projected on the road R with the contour shape of the light receiving surface 14a of the light receiving element 14 reversed in 180 ° in both the vertical and horizontal directions. Set to do. That is, in FIG. 4A, the upper end edge 14a1 of the light receiving surface 14a corresponds to the position b that is the downstream end of the uplink area UA, and the lower end edge 14a2 is the position c that is the upstream end of the uplink area UA. It will correspond to.
Therefore, for example, if the vehicle C transmits uplink information from a predetermined position in the uplink area UA, the transmitted uplink information is geometrically determined on the light receiving surface 14a of the light receiving unit 12. A predetermined position is irradiated.

FIG. 4B is a diagram when the light receiving surface 14a of the light receiving element 14 is viewed from the front. In the drawing, the vertical direction of the paper corresponding to the vehicle traveling direction is the x direction, and the horizontal direction of the paper corresponding to the width direction of the road R is the y direction.
As shown in the figure, the light receiving surface 14a has a rectangular outline shape. The uplink information of the in-vehicle device 2 is condensed by the condensing lens 15 and is spot-irradiated on the light receiving surface 14a, so that the light receiving element 14 displays the uplink information in a part of the range of the light receiving surface 14a. Receive light.
The light receiving unit 12 further includes a control unit 16 interposed between and connected to the light receiving element 14 and the beacon controller 7 (FIG. 1). Various information stored in the link information is output to the control unit 16 as an electrical signal. The control unit 16 outputs this electric signal to the beacon controller 7.

Further, the light receiving unit 12 can output various kinds of information included in the uplink information as electric signals, and at the same time, can output light receiving position information related to the light receiving position where the uplink information in the x direction of the light receiving surface 14a is received.
The light receiving element 14 includes a first output electrode 17 and a second output electrode 18 provided along the upper edge 14a1 and the lower edge 14a2 of the light receiving surface 14a, respectively. A common electrode as a whole of the light receiving element 14 (not shown) is connected to the control unit 16. The light receiving element 14 outputs an electric signal including the above-described various information to the control unit 16 from these electrodes.

Here, for example, if the light receiving element 14 receives the uplink information in the range indicated by the broken line Q in the figure, the distance q1 from the light receiving position to the first output electrode 17 and the second output electrode from the light receiving position. This is different from the distance q2 up to 18. At this time, the electric signal charge output from the light receiving element 14 is divided in inverse proportion to the distance and output from both output electrodes 17 and 18. This is because if the distance to reach the electrode is relatively long, the resistance value is also relatively large. The control unit 16 can grasp the light receiving position in the x direction of the light receiving surface 14a by acquiring the difference between the current values output from the output electrodes 17 and 18.
Since the light receiving element 14 has no output electrode on both sides, the light receiving position in the y direction cannot be grasped.

The control unit 16 is configured to output the light receiving position information regarding the light receiving position in the x direction of the light receiving surface 14a, for example, as a coordinate value t1 in the x direction with reference to the reference line S in the drawing. The coordinate value t1 is output so that the value on the reference line S is 0 and takes a positive value on the upper side of the paper and a negative value on the lower side.
The control unit 16 outputs the light receiving position information to the beacon controller 7 together with the electric signal including various information stored in the uplink information.

[Understanding the transmission position where the in-vehicle device sent the uplink information]
The beacon controller 7 can grasp the transmission position where the in-vehicle device 2 transmits the uplink information in the uplink area UA based on the light receiving position information output from the control unit 16 of the light receiving unit 12.
That is, as shown in FIG. 4A, the upper end edge 14a1 of the light receiving surface 14a corresponds to the position b which is the downstream end of the uplink area UA, and the lower end edge 14a2 is upstream of the uplink area UA. If the in-vehicle device 2 corresponds to the position c, which is the end, and the uplink information is transmitted from a predetermined position in the uplink area UA, the transmitted uplink information is transmitted to the light receiving surface of the light receiving unit 12. On 14a, a predetermined position determined geometrically is irradiated and received.
For example, the in-vehicle device 2 transmits uplink information from a point e in FIG. 4A, and the transmitted uplink information is received at a portion indicated by a broken line Q on the light receiving surface 14a in FIG. 4B. Assuming that the distance D from the position c to the position e (FIG. 4 (a)) and the distance q2 (FIG. 4 (b)) corresponding to the distance D on the light receiving surface 14a, the following formula ( The relationship shown in 1) is established.
D / L1 = (T / q2) × Z (1)

In the above formula (1), T is the width dimension in the x direction of the light receiving surface 14a, and L1 is the distance in the vehicle traveling direction of the uplink area UA. Z is a correction parameter, and the light receiving surface 14a and the road R are not in a parallel relationship as shown in FIG. 4A, so that the relationship between the values of the distance D and the distance q2 is corrected. Multiply.
Moreover, the distance q2 is calculated | required by following formula (2) based on coordinate value t1. The coordinate value t1 is output as light receiving position information by the detection unit 12 as described above.
q2 = (1/2) T + t1 (2)

  As described above, when the optical beacon 4 is installed, the above formulas (1) and (2) are obtained by grasping the distance L1 in the vehicle traveling direction of the uplink area UA and the width dimension T of the light receiving surface 14a. ) To obtain the distance D.

When the beacon controller 7 receives the light receiving position information (coordinate value t1) output from the light receiving unit 12, the beacon controller 7 calculates based on the above formulas (1) and (2), and the in-vehicle device 2 operates in the uplink area UA. The transmission position where the uplink information is transmitted can be grasped as the distance D with reference to the position c which is the upstream end of the uplink area UA.
The beacon controller 7 generates vehicle-mounted device position information based on the distance D as the transmission position, stores this in the second downlink information, and transmits it to the vehicle-mounted device 2.

[Configuration of in-vehicle device and vehicle]
FIG. 5 is a schematic configuration diagram of the in-vehicle device 2 that performs road-to-vehicle communication with the optical beacon 4 and a vehicle C in which the in-vehicle device 2 is mounted.
As shown in FIG. 5, the vehicle C includes a vehicle body 21 having a driver's boarding seat (not shown), the vehicle-mounted device 2 mounted on the vehicle body 21, and electronic control that integrally controls each part of the vehicle C. An apparatus (ECU) 22, an engine 23 that drives the vehicle body 21, a brake device 24 that brakes the vehicle body 21, and a speed detector 25 that constantly detects the current speed of the vehicle C are provided. The ECU 22 performs various controls on the vehicle C, such as drive control of the engine 23 based on the accelerator operation of the driver and braking control based on the brake operation.

The in-vehicle device 2 includes an in-vehicle computer 26, an in-vehicle head (projector / receiver) 27 connected to the sensor interface of the computer 26, a display 28 and a speaker device 29 as a human interface for the driver of the passenger seat. Yes.
The vehicle-mounted head 27 includes a light emitting diode (LED) and a photosensor (not shown), similar to the light beacon projector / receiver 8. Among these, the LED emits uplink information composed of near infrared rays, and the photosensor receives downlink information composed of near infrared rays emitted to the communication area A.

The in-vehicle computer 26 includes a programmable microcomputer having a CPU, a memory (RAM), and a storage device (ROM), and performs control processing for road-to-vehicle communication with the optical beacon 4 by the in-vehicle head 27.
The in-vehicle computer 26 stores a program for executing each predetermined function in a storage device, and includes a distance recognition unit 30 and a support control unit 32 as functional units executed by the program. The processing contents of these functional units 30 and 32 will be described later.

[Contents of road-to-vehicle communication]
FIG. 6 shows a bidirectional road-to-vehicle communication procedure performed between the projector / receiver 8 and the in-vehicle head 27 in the communication area A. Hereinafter, the contents of the road-to-vehicle communication of the present embodiment will be described with reference to FIG.
First, the beacon controller 7 of the optical beacon 4 sends the first downlink information 34 including the lane notification information as the first information before switching the downlink from the projector / receiver 8 corresponding to each lane R1 to R4. , The transmission continues to the downlink area DA of each lane R1 to R4 at a predetermined transmission cycle (F1 in FIG. 6). At this stage, the vehicle ID is not yet stored in the lane notification information.

When the vehicle C equipped with the vehicle-mounted device 2 enters the actual downlink area DA, the vehicle-mounted head 27 of the vehicle-mounted device 2 receives the first downlink information 34 including lane notification information (no vehicle ID).
At this time, the in-vehicle computer 26 of the in-vehicle device 2 recognizes that the vehicle C exists in the actual communication area A. Thereafter, the in-vehicle computer 26 starts transmission of the uplink information 35 (F2 in FIG. 6), and transmits this uplink information 35 to the projector / receiver 8 at a predetermined transmission cycle (uplink transmission cycle) ( F3 in FIG. 6).

  The in-vehicle computer 26 stores a specific vehicle ID for the vehicle C in the uplink information 35 and transmits the uplink information 35. If the in-vehicle computer 26 has travel time information between beacons, this information is also uploaded. It is included in the link information 35. The in-vehicle computer 26 continues to transmit the uplink information 35 until it recognizes that the beacon controller 7 of the optical beacon 4 has switched the downlink.

  On the other hand, when the projector / receiver 8 of the optical beacon 4 receives the uplink information 35 (F4 in FIG. 6), the beacon controller 7 performs downlink switching, and lane notification information having vehicle ID information as the second information. Is started (F5 in FIG. 6), and the transmission of the second downlink information 36 is repeated as much as possible within a predetermined time (F6 in FIG. 6).

  The lane notification information includes a field for storing a vehicle ID for each lane R1 to R4 (FIG. 2), and a lane number can be assigned to each vehicle ID. For this reason, the in-vehicle computer 26 of each vehicle C traveling in different lanes R1 to R4 determines which lane R1 to R4 the host vehicle is in by determining which of the storage fields includes the vehicle ID of the host vehicle. Can recognize if you are driving.

In addition to the lane notification information including the vehicle ID, the second downlink information 36 includes traffic information, section travel time information, event regulation information, and support information for safe driving support for the driver. Yes.
This support information includes signal information that is timing information for changing the lamp color of the traffic light downstream from the optical beacon 4 and vehicle-mounted device position information that will be described later.

As shown in FIG. 6, the second downlink information 36 includes a single or a plurality of minimum frames 37. According to the “near infrared interface standard”, the data amount of the minimum frame 37 is defined as a total of 128 bytes, and 5 bytes are allocated to the header portion 38 and 123 bytes are allocated to the actual data portion 39.
According to the standard, the second downlink information 36 can be composed of 1 to 80 minimum frames 37, and the transmittable time is set to 250 ms. The downlink information 36 includes an arbitrary number of minimum frames 37 corresponding to the amount of information to be transmitted, and is repeatedly transmitted within the range of the transmittable time.

The transmission period of the minimum frame 37 is about 1 ms. Therefore, for example, when one downlink information 36 is constituted by three minimum frames 37, the transmission period of the downlink information 36 is about 3 ms. Therefore, the downlink information 36 has a predetermined transmittable time (250 ms). ) Will be repeatedly transmitted about 80 times during this period.
The in-vehicle computer 26 of the in-vehicle device 2 recognizes the downlink switching in the optical beacon 4 at the time of receiving the second downlink information 36 (F7 in FIG. 6), and transmits the uplink information 35 at this time. Stop.

The in-vehicle computer 26 of the in-vehicle device 2 uses the stop line P0 as a predetermined position downstream from the current position of the vehicle C based on various information such as the support information included in the received second downlink information 36. The position is determined by recognizing the distance (F8 in FIG. 6), and based on this, safe driving support for the driver is performed.
Hereinafter, the content of the above-mentioned in-vehicle device position information and distance recognition for safe driving support performed by the in-vehicle device 2 based on this will be described.

[On-vehicle device location information]
The in-vehicle device position information is information indicating a transmission position at which the in-vehicle device 2 transmits the uplink information in the uplink area UA, and the beacon controller is in a stage where the optical beacon 4 receives the uplink information from the in-vehicle device 2. 7 is generated.
For example, when the vehicle C (onboard unit 2) located at the position P in the uplink area UA in FIG. 3 transmits the uplink information 35 and the optical beacon 4 receives this, the light receiving unit of the light projecting / receiving device 8 12 outputs light receiving position information to the beacon controller 7 as described above. Receiving this, the beacon controller 7 uses the position P, which is the transmission position to which the in-vehicle device 2 has transmitted the uplink information, in the uplink area UA as the distance D with reference to the position c that is the upstream end of the uplink area UA. To grasp as.

The beacon controller 7 determines the distance L0 from the position c, which is the upstream end of the uplink area UA, to the stop line P0 as a predetermined position on the downstream side, and the distance in the vehicle traveling direction of the uplink area UA on the road R. L1 is stored in the storage device in advance, and the distance L2 from the position P of the vehicle-mounted device 2 to the stop line P0 on the downstream side is calculated as distance information based on the distances L0 and L1 and the distance D.
The beacon controller 7 stores the calculated distance information as in-vehicle device position information in the second downlink information and transmits it to the projector / receiver 8.
The in-vehicle device 2 receives the second downlink information including the in-vehicle device position information transmitted from the light projector / receiver 8 and obtains the in-vehicle device position information, thereby providing safe driving support.

  As described above, the beacon controller 7 generates on-vehicle device position information indicating the position P that is the transmission position based on the light reception position information output by the light receiving unit 12, and the down-converter includes the on-vehicle device position information. The control part which transmits link information to the light projector / receiver 8 is comprised.

[Contents of distance recognition (safe driving support)]
As shown in FIG. 5, when the vehicle-mounted head 27 receives the second downlink information 36 including the vehicle-mounted device position information and the like, the distance recognition unit 30 of the vehicle-mounted computer 26 is included in the frame of the downlink information 36. Vehicle-mounted device position information is acquired, and the distance L2 as the distance information is recognized.
And the assistance control part 32 of the vehicle-mounted computer 26 performs the safe driving assistance with respect to a driver using the distance L2.
Here, the vehicle-mounted device 2 mounted on the vehicle C has a height dimension H from the road R as shown in FIG. Moreover, since the vehicle-mounted head 27 of the vehicle-mounted device 2 is normally fixed on the dashboard, the vehicle-mounted head 27 is disposed rearward from the front end of the vehicle C by the width dimension D2. For this reason, there is a possibility that an error occurs in the distance L2 due to the height dimension H and the width dimension D2, but the in-vehicle computer 26 stores the height dimension H and the width dimension D2 in advance. An error due to these dimensions is corrected, and a more accurate distance L2 can be obtained.

  For example, the support control unit 32 calculates a deceleration (negative acceleration) for stopping before the stop line P0 from the distance L2 to the stop line P0 and the current traveling speed of the vehicle C, and reduces the decrease. The ECU 22 is notified of the speed. The ECU 22 operates the brake device 24 so as to achieve the deceleration, whereby the vehicle C can be automatically stopped before the stop line P0.

Further, the safe driving support of the support control unit 32 may be alerting the driver using the display 28 or the speaker device 29.
For example, the distance L2 to the stop line P0 may be displayed on the display 28 by the support control unit 32. When the current traveling speed of the vehicle C is too fast, the support control unit 32 displays a warning for stopping or decelerating on the display 28, or outputs the warning from the speaker device 29 as a voice. May be.

Moreover, the assistance control part 32 can also perform safe driving assistance using the signal information contained in 2nd downlink information with the said vehicle equipment position information.
Here, the signal information refers to information related to the current or future signal lamp color displayed by the traffic signal device, and includes information (display schedule information) regarding the display continuation period of each signal lamp color, the display order, and the like. For example, “the current lamp color is blue and the scheduled duration is 5 seconds, the next lamp color is yellow and the scheduled duration is 8 seconds, and the next lamp color is a right turn blue arrow lamp and the scheduled duration is 10 seconds. It is information such as “second”.

  The support control unit 32 of the in-vehicle computer 27 that has received this signal information takes the time required to arrive at the stop line P0 from the distance L2 to the stop line P0 (the above-mentioned distance information), the traveling speed, acceleration, etc. of the vehicle C. , And the signal lamp color after the required time has elapsed can be estimated. For example, when the current signal lamp color is a blue signal, but the signal lamp color is predicted to be a red signal when arriving at the stop line P0, it can be safely stopped before the stop line P0. Thus, control for braking the vehicle C is performed. Conversely, if it can be determined that the vehicle can safely pass through the intersection unless the vehicle is decelerated, the control for maintaining the speed of the vehicle C can be performed.

  In order to brake the vehicle C and maintain the speed, the support control unit 32 may directly control the brake device 24 (FIG. 5) and the accelerator of the vehicle. Further, the support control unit 32 may simply generate information related to braking and speed maintenance and notify the ECU 22 of the information to control the brake device 24 and the accelerator by the ECU 22. That is, the support control unit 32 may perform indirect control.

  In addition, the support control unit 32 may perform not only control led by the in-vehicle device but also operation for assisting the driving operation of the driver such as brake assist.

The support control unit 32 may notify the passenger of the vehicle C of the result of the signal lamp color estimation by voice or image information. For example, sound such as “Since the signal changes soon and should be stopped” is emitted from the speaker device 29 to the driver, or displayed on the display 28 such as a head-up display or a navigation device with characters or symbols. Can do.
For safe driving assistance, a human interface that does not notify the driver of information at an inappropriate timing or content, for example, it is possible to prevent notification by voice or image display during low-speed driving .

The signal information may be only the currently displayed lamp color and its duration, or information for one cycle may be provided collectively. Further, in addition to these pieces of information, parameter information related to the control, information on a time zone in which the control is performed, and the like may be included at the point where the point sensitive control is performed.
The signal information may be acquired from an optical beacon or may be acquired from an infrastructure device other than the optical beacon. In the latter case, for example, when the signal controller of the traffic signal is equipped with a wireless communication device, it may be acquired from the wireless communication device, or may be acquired by inter-vehicle communication from the preceding vehicle that acquired the signal information. Also good. The signal information receiving unit that receives the signal information may use the in-vehicle head 27 or may be another receiver provided in the in-vehicle device 2.

According to the road-to-vehicle communication system and the optical beacon 4 configured as described above, the beacon controller 7 determines the position P, which is the transmission position, based on the light reception position information output by the light receiving unit 12 of the light projecting / receiving device 8. The on-vehicle device position information is generated and the second downlink information including the on-vehicle device position information is transmitted to the projector / receiver 8 so that the optical beacon 4 is up regardless of whether the uplink area UA is wide or narrow. In the link area UA, the in-vehicle device 2 can recognize the transmission position (position P) from which the on-vehicle device 2 has transmitted the uplink information, and the in-vehicle device 2 can recognize this transmission position.
Furthermore, in this embodiment, since the said vehicle equipment position information contains the distance L2 from the said transmission position to the stop line P0 of the downstream as distance information, the exact distance to the vehicle equipment 2 to the stop line P0 is correct. Can be recognized, and safe driving support can be performed with high accuracy.

In the present embodiment, the beacon controller 7 calculates the distance L2 from the position P that is the transmission position of the in-vehicle device 2 to the stop line P0 as the in-vehicle device position information, but for example, upstream of the uplink area UA. The distance L0 from the position c that is the end to the stop line P0 is used as the first distance information, the distance D between the position P and the position c is used as the second distance information, and both these pieces of distance information are used as the in-vehicle device position information. You may send as.
In this case, the distance recognition unit 30 of the vehicle-mounted device 2 that has received the vehicle-mounted device position information performs a calculation of subtracting D from the distance L0, and a stop line downstream from the transmission position (position P) obtained by this calculation. By using the distance L2 to P0, it is possible to perform safe driving support for the driver in the same manner as described above.

[Second Embodiment]
FIG. 7 is a side view showing the communication area A of the optical beacon 4 according to the second embodiment of the present invention.
The difference between this embodiment and the first embodiment is that the beacon controller 7 divides the light receiving position information output from the light receiving unit 12 into four numerical ranges, and determines the position of the vehicle C for each numerical range. Thus, the uplink area UA is substantially divided into four areas. Since other points are the same as those in the first embodiment, description thereof is omitted.

  As shown in FIG. 7, the uplink area UA of the present embodiment is substantially divided into four divided areas UA1 to UA4, and the beacon controller 7 includes these divided areas UA1 to UA1. It is specified in which of UA4 the vehicle C exists. In each of the divided areas UA1 to UA4, when the vehicle C exists in the divided area, the distances L11 to L14 from the positions P1 to P4 that the vehicle C is considered to be located to the stop line P0 are set. The beacon controller 7 stores the distance L0 and the distances L11 to L14.

FIG. 8 is a view of the light receiving surface 14a of the light receiving unit 12 according to the present embodiment when viewed from the front. As described above, the beacon controller 7 divides the light receiving position information output from the light receiving unit 12 into four numerical ranges, and determines the position of the vehicle C for each numerical range.
For example, as shown in FIG. 8, the numerical range is set so that the light receiving surface 14a has four regions 19a to 19d for each width T1 along the x direction (vehicle traveling direction). These four areas 19a to 19d correspond to the divided areas UA1 to UA4, respectively.
Here, the light receiving position information is output as a coordinate value t1 with reference to the reference line S, but the values on the light receiving surface 14a and the reference line S are 0, plus on the upper side of the page and minus on the lower side. Is output to take the value of. Accordingly, the numerical range of the coordinate value t1 is determined as follows.
Region 19a: t1 ≦ −T1
Region 19b: −T1 <t1 ≦ 0
Region 19c: 0 <t1 ≦ T1
Region 19d: t1> T1

The beacon controller 7 stores the above four numerical ranges, and the light receiving position information output from the light receiving unit 12 specifies which numerical range the four numerical ranges belong to. It is specified whether the vehicle C exists in any of the divided areas UA1 to UA4.
As described above, the beacon controller 7 substantially divides the light receiving surface 14a into the four regions 19a to 19d arranged in the direction corresponding to the vehicle traveling direction based on the numerical value of the light receiving position information. The uplink area UA is divided into four divided areas UA1 to UA4 arranged in the vehicle traveling direction.
When the divided area where the vehicle C exists is specified, the beacon controller 7 selects a distance corresponding to the specified divided area from the distances L11 to L14, and uses the second downlink as the in-vehicle apparatus position information. It is stored in information and transmitted to the in-vehicle device 2.
The in-vehicle device 2 can perform safe driving support by receiving the second downlink information including the in-vehicle device position information and acquiring the in-vehicle device position information.

In the present embodiment, the beacon controller 7 can selectively acquire the distance information by preparing information related to the distance corresponding to each divided area in advance.
Further, since the uplink area UA is substantially divided into four divided areas UA1 to UA4, for example, when an error is likely to occur in the light receiving position information of the light receiving unit 12 due to an external factor such as an installation environment, Since each of the divided areas UA1 to UA4 and the areas 19a to 19d has a predetermined numerical value width, an error is allowed and information such as an accurate distance can be provided to the in-vehicle device 2.

The present invention is not limited to the above embodiments. For example, the light receiving element 14 in each of the above embodiments uses an element that outputs light receiving position information only in the x direction. However, output electrodes are also arranged on both sides, and light is received in both the x direction and the y direction. A light receiving element that can output position information may be used.
In addition, the light receiving unit 12 outputs the light receiving position information as a coordinate value with reference to the reference line S (see FIG. 4B). For example, the lower end edge 14a2 corresponding to the upstream end of the uplink area UA is displayed. It may be configured to output as a reference value. In this case, it goes without saying that the formulas (1), (2) and the like are changed according to this.

Further, in the above embodiment, the beacon controller 7 has a distance L0 from the position c that is the upstream end of the uplink area UA to the stop line P0 as a predetermined position on the downstream side, and the uplink area on the road R. By storing the distance L1 in the vehicle traveling direction of the UA in the storage device in advance, the uplink area UA as the position on the road R and the position on the light receiving surface 14a of the light receiving unit 12 are associated with each other to be mounted in the vehicle. Although the position information has been generated, for example, the beacon controller 7 may be configured to generate the light receiving position information received from the light receiving unit 12 in association with the corresponding latitude and longitude on the road.
In this case, the distance to the stop line P0 can be calculated from the latitude and longitude. In this case, the latitude and longitude indicating the position of the required downstream stop line P0 may be stored in the beacon controller 7 and transmitted in the downlink information, or may be transmitted from another wireless communication device. You may transmit separately, and the vehicle-mounted computer 26 of the vehicle equipment 2 may memorize | store beforehand.

  In addition, the contour shape of the light receiving surface 14a of the light receiving unit 12 is a rectangular shape in each of the above embodiments. For example, as shown in FIGS. 9A and 9B, the contour shape of the light receiving surface 14a is formed at the upstream end of the uplink area UA. A corresponding trapezoidal shape with a short side on the lower end edge 14a2 side or a pentagonal shape with a further short side protruding further to the upstream side can be used. As shown in FIG. 4A, the light projector / receiver 8 of the optical beacon 4 projects the uplink area UA obliquely downward in the upstream direction, so the upstream end side of the uplink area UA is more than the downstream end side. In some cases, the contour is deformed and projected, such as spreading or an upstream end projecting. If the contour of the uplink area UA is deformed and projected as described above, there is a possibility that appropriate road-to-vehicle communication may be hindered, for example, the uplink area UA deviates from an adjacent lane. By using a trapezoidal shape or a pentagonal shape as shown in FIG. 9, the deformation can be corrected, and more appropriate road-to-vehicle communication can be performed.

(A) is a block diagram which shows the whole structure of the road-to-vehicle communication system which concerns on 1st embodiment of this invention. It is a top view of an optical beacon. It is a side view which shows the communication area | region A of an optical beacon. (A) is the side view which showed the geometric positional relationship of a light-receiving part and the uplink area | region set on a road, (b) is when the light-receiving surface of a light-receiving element is seen from the front FIG. FIG. 2 is a schematic configuration diagram of the in-vehicle device that performs road-to-vehicle communication with an optical beacon and a vehicle in which the in-vehicle device is mounted. It is the figure which showed the procedure of the two-way road-to-vehicle communication performed between a light projector / receiver and an onboard equipment in a communication area. It is a side view which shows the communication area | region of the optical beacon of 2nd embodiment of this invention. It is a figure when the light-receiving surface of the light-receiving part of this embodiment is viewed from the front. (A) And (b) is the figure which showed the other aspect about the outline shape of the light-receiving surface of a light-receiving part. It is a side view which shows the communication area | region of the conventional optical beacon.

Explanation of symbols

2 In-vehicle device 4 Optical beacon 7 Beacon controller (control unit)
8 Emitter / Receiver 12 Light Receiving Unit 14a Light Receiving Surface 30 Distance Recognition Unit 32 Support Control Unit A Communication Area C Vehicle R Road P0 Stop Line (Predetermined Position)
DA Downlink area UA Uplink area

Claims (8)

An optical beacon having a light emitter / receiver that sets a communication area composed of an uplink area capable of receiving uplink information and a downlink area capable of transmitting downlink information to a predetermined range of the road, and mounted on a vehicle, A vehicle-to-vehicle communication system comprising: an in-vehicle device that transmits and receives the uplink information and the downlink information to and from the projector and receiver in the communication region,
The light emitter / receiver includes a light receiving unit having a light receiving surface for receiving the uplink information, and the light receiving unit sets the uplink region so as to project the light receiving surface onto the road, and the light receiving unit. The light receiving position information on the light receiving position that received the uplink information on the surface is output,
The optical beacon generates on-vehicle device position information indicating a transmission position at which the in-vehicle device transmits the uplink information in the uplink region based on the light reception position information output from the light receiving unit. A controller that transmits the downlink information including the position information to the projector / receiver ;
The in-vehicle device position information includes distance information related to a distance from the transmission position to a predetermined position downstream thereof, and first distance information about a distance from the upstream end of the uplink region to the predetermined position. And a second distance information about a distance from the transmission position to the upstream end of the uplink region as the distance information . The road-to-vehicle communication according to claim 1 , wherein the in-vehicle device has a distance recognition unit that obtains a distance from the transmission position to the predetermined position from the first distance information and the second distance information. system. Projector / receiver for setting a communication area including an uplink area capable of receiving uplink information from an in-vehicle device of a vehicle traveling on a road and a downlink area capable of transmitting downlink information to the in-vehicle device to a predetermined range of the road An optical beacon having
The light emitter / receiver includes a light receiving unit having a light receiving surface for receiving the uplink information, and the light receiving unit sets the uplink region so as to project the light receiving surface onto the road, and the light receiving unit. The light receiving position information on the light receiving position that received the uplink information on the surface is output,
The optical beacon generates on-vehicle device position information indicating a transmission position at which the in-vehicle device transmits the uplink information in the uplink region based on the light reception position information output from the light receiving unit. A controller that transmits the downlink information including the position information to the projector / receiver ;
The in-vehicle device position information includes distance information related to a distance from the transmission position to a predetermined position downstream thereof, and first distance information about a distance from the upstream end of the uplink region to the predetermined position. And the second distance information about the distance from the transmission position to the upstream end of the uplink region as the distance information . An in-vehicle device used in the road-vehicle communication system according to claim 1 ,
An in-vehicle device having a distance recognizing unit that recognizes a distance to the predetermined position based on the in-vehicle device position information included in the predetermined downlink information. A signal information receiving unit that receives signal information related to a display schedule of a traffic light set downstream in the vehicle traveling direction, and a support control unit that performs control related to driving support based on the signal information and the distance information The in-vehicle device according to claim 4 . The in-vehicle device according to claim 5, wherein the support control unit performs control for braking the vehicle. The in-vehicle device according to claim 5 or 6 , wherein the support control unit has a function of generating notification information for a passenger of the vehicle. A vehicle equipped with the in-vehicle device according to any one of claims 4 to 7 .

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