JP2009122804A - Device, system and method for supporting safety drive, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safety drive support device for preliminarily preventing warning leakage to a driver to be caused due to a positioning error. <P>SOLUTION: The safety drive support device 24 decides whether entering of a vehicle C traveling on a road W toward an intersection 5 to an intersection 5 is dangerous, and issues a warning to the driver of the vehicle C when it is dangerous. The support device 24 acquires the signal switching timing ts of the intersection 5, the current location Pc of the vehicle C, the error upper limit R of the current location Pc, the stop location Xp before the intersection 5 and the traveling speed V of the vehicle C, and calculates the maximum prediction requirement time T2 to the stop location Xp on the basis of the current location Pc of the vehicle C, the error upper limit R of the current location Pc, the stop location Xp and the traveling speed V of the vehicle C, and decides whether the entering of the vehicle to the intersection 5 is dangerous on the basis of the signal switching timing ts at the elapsed time t2 of the maximum prediction requirement time T2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a safe driving support device, a safe driving support system, a safe driving support method, and a computer program for causing a computer to execute these methods.

Based on communication information including an in-vehicle device of a vehicle traveling on a road and a roadside device communicable with the in-vehicle device, including signal switching timing provided from the roadside device to the in-vehicle device, a distance to a stop line, and the like A safe driving support system for determining whether it is dangerous for a vehicle traveling on a road toward an intersection to enter the intersection has already been proposed.
In such a safe driving support system, when the above determination result is dangerous, the driver is warned to that effect, or the vehicle is automatically braked when the driver does not perform a braking operation. (For example, refer to Patent Document 1).

Japanese Patent No. 3005866

In the safe driving support system described in Patent Document 1, an error regarding the distance from the roadside device to the stop line, which is a kind of positioning information of the vehicle, is not considered, so it is determined that entering the intersection is dangerous. There is a case where a “missing warning” occurs that is not warned by the driver.
Specifically, if the current position of the actual vehicle is behind the current position provided by the roadside device due to positioning error, a green signal is displayed when the estimated time required for the vehicle to reach the stop line has elapsed. Even if it is determined, the signal light color when the vehicle actually reaches the stop line may be red (see FIG. 2). In such a case, the driver should determine that entering the intersection is dangerous. “Warning leak” that is not warned.

  Conversely, if the current position of the actual vehicle is ahead of the current position provided by the roadside device due to positioning error, a green signal is displayed when the estimated time required until the vehicle reaches the stop line. Even if it is determined, the signal light color when the vehicle actually reaches the stop line may be red (see FIG. 3). In such a case, the driver should determine that entering the intersection is dangerous. “Warning leak” that is not warned.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a safe driving support device, a safe driving support system, and the like that can prevent a warning from being leaked to a driver caused by a positioning error. .

The safe driving support device according to the present invention (Claim 1) determines whether or not a vehicle traveling on a road toward an intersection is dangerous to enter the intersection, and warns the driver of the vehicle if it is dangerous. A safe driving support device,
An acquisition unit that acquires the signal switching timing of the intersection, information on a distance between the current position of the vehicle and a stop position before the intersection, an error setting value of the current position, and a traveling speed of the vehicle; A calculation unit for calculating a maximum estimated required time to the stop position based on information on a distance between the current position of the vehicle and the stop position, an error setting value of the current position and a travel speed of the vehicle; And a determination unit that determines whether or not the approach to the intersection is dangerous based on the signal switching timing when the maximum estimated required time has elapsed.

According to the safe driving support apparatus of the present invention, the calculation unit calculates the maximum predicted required time to the stop position in consideration of the error setting value of the current position of the vehicle, and the determination unit calculates the maximum predicted required time. It is determined whether or not it is dangerous to enter the intersection based on the signal switching timing at the elapse of.
For this reason, there is a positioning error in the current position of the vehicle, so even if the actual vehicle is behind the current position acquired by the acquisition unit, the estimated required time to the stop line is estimated to be shorter than the actual time. Thus, “warning omission” that is not warned by the driver even though the approach to the intersection should be judged as dangerous is prevented.
In the safe driving support apparatus, the information on the distance between the current position and the stop position may be information on the distance itself, or information on the current position and the stop position for calculating the distance. The information is not particularly limited as long as the distance is required.

  In the safe driving support device of the present invention, the calculation unit further stops the stop based on information on a distance between the current position of the vehicle and the stop position, an error setting value of the current position, and a travel speed of the vehicle. Calculating the minimum required travel time to the position, and the determination unit further determines whether it is dangerous to enter the intersection based on the signal switching timing when the minimum predicted travel time has elapsed (Claim 2).

According to the above safe driving support device, the calculation unit calculates the minimum predicted required time to the stop position in consideration of the error setting value of the current position of the vehicle, and the determination unit passes the minimum predicted required time. It is determined whether it is dangerous to enter the intersection based on the signal switching timing at the time.
For this reason, because there is a positioning error in the current position of the vehicle, even if the actual vehicle is ahead of the current position acquired by the acquisition unit, the estimated required time to the stop line is estimated to be longer than the actual time. Thus, “warning omission” that is not warned by the driver even though the approach to the intersection should be judged as dangerous is prevented.

In the safe driving support device of the present invention, the “error setting value” means an error setting value that can normally occur at the current position of the vehicle, or an error setting value that is expected to be larger than this. In general, an upper limit of error is adopted.
As described above, the error setting value is a kind of control margin, but when it is determined whether or not it is dangerous to enter the intersection in consideration of the error setting value, the error setting value is set to a predetermined setting value in advance. If it is fixed to, there is a risk that safe driving assistance in conformity with the actual situation cannot be performed.
For example, if the error setting value is set too large, if the actual positioning error is smaller than that, it may become a “false warning” that is judged as dangerous even though the vehicle can safely pass the intersection. The nature will increase.

Therefore, in order to make the above error setting value as close as possible to the actual positioning error, it is recommended to perform a process for determining whether or not the approach to the intersection is safe in consideration of temporal variation of the error setting value. The
That is, in the safe driving support device of the present invention, the acquisition unit can acquire a high-precision current position of the vehicle measured with higher accuracy than a positioning function that the vehicle normally has, and the calculation unit Preferably, the error setting value is determined in accordance with an elapsed time after passing through the high-accuracy current position or a movement distance from the high-accuracy current position.

According to the safe driving support apparatus, the calculation unit determines the error setting value according to the elapsed time or the moving distance, and therefore the error setting value can be as close as possible to the actual positioning error.
For this reason, compared with the case where the error set value is set to a constant set value, a situation in which an “false warning” is issued can be prevented, and the determination accuracy can be improved.

In the safe driving support device of the present invention, the calculation unit may determine the error setting value according to an error estimated value calculated using a positioning device included in the vehicle.
For example, when the vehicle positioning device is a GPS device, the estimated error value is calculated as a horizontal dilution of precision (HDOP) and a user equivalent ranging error that can be calculated at a fixed positioning cycle in the GPS receiver. It can be obtained by doubling the product of (UERE: User Equivalent Ranging Error).

  Even when the error setting value is determined according to the error estimation value dynamically calculated by the GPS receiver in this way, the error setting value can be made as close as possible to the actual positioning error, and the error setting value can be kept constant. Compared with the case where the set value is used, it is possible to prevent the occurrence of a “false warning” on the contrary.

  More specifically, in the safe driving support device of the present invention, the determination unit more specifically, the intersection at the reference time of either the elapse of the maximum predicted required time or the elapse of the minimum predicted required time. To the intersection by determining whether or not the time from one reference time to the other reference time is included in the green light time at the intersection. It is preferable to determine whether or not the approach is dangerous.

In this case, it is determined whether or not the signal light color at the intersection at one reference is blue, and then it is determined whether or not the time of both the reference times is included in the green signal time. It can be determined whether or not there is a change in signal lamp color during the estimated required time.
For this reason, for example, at the intersection that will be approached, both reference times are green, but even when there is a short red signal between them, it is accurately determined whether or not it is dangerous to enter the intersection. It can be carried out.

In the safe driving support apparatus of the present invention, the positioning device that the vehicle normally has includes, for example, a wheel speed sensor, a direction sensor, and a position detector such as a GPS, and the high-precision current position of the vehicle is more accurate than the position detector. Is composed of a high-precision positioning device.
As such a high-accuracy positioning device, there is an optical beacon installed on the road as the most feasible at the present time. In this case, the acquisition unit uses the downlink information from the optical beacon to obtain high-accuracy. The current position is acquired (claim 6).

A safe driving support system according to the present invention (Claim 7) includes an in-vehicle device of a vehicle traveling on a road and a roadside device (a beacon controller, a signal controller, etc.) capable of communicating with the in-vehicle device. The vehicle-mounted device is provided with a calculation unit and a determination unit, which are constituent elements of the safe driving support device of the present invention (Claim 1).
Therefore, the safe driving support system of the present invention (Claim 7) also has the same effects as the safe driving support device (Claim 1).

Further, the computer program of the present invention (Claim 8) causes each function of the function realizing means (acquisition unit, calculation unit, and determination unit) constituting the safe driving support apparatus (Claim 1) of the present invention to be executed. Yes, there are the same effects as the support device.
Furthermore, the safe driving support method of the present invention (Claim 9) is a method performed by the safe driving support device of the present invention (Claim 1), and has the same operational effects as the support device.

  As described above, according to the present invention, it is determined whether or not it is dangerous to enter the intersection based on the estimated required time to the stop position calculated in consideration of the error setting value of the current position of the vehicle. It is possible to prevent a warning from being leaked to the driver due to the above.

[Overall system configuration]
FIG. 1 is a block diagram showing the overall configuration of a safe driving support system according to an embodiment of the present invention, and FIGS. 2 and 3 are side views of a road showing the overall configuration of the support system.
As shown in FIG. 1, the safe driving support system 1 includes an optical beacon 2 and a traffic signal 3 that are roadside devices installed on a road W, and an in-vehicle device 4 mounted on a vehicle C traveling on the road W. I have.

  In the support system 1, the vehicle-mounted computer (safe driving support device) 24 of the vehicle-mounted device 3 travels on the road W toward the intersection 5 based on communication information provided from the roadside devices 2 and 3 to the vehicle-mounted device 3. It is determined whether or not it is dangerous for the vehicle C to enter the intersection 5 and if the determination result is dangerous, a warning is issued to the driver of the vehicle C or automatic braking of the vehicle C is performed. .

The optical beacon 2 and the traffic signal 3 are communicably connected to a central device (not shown) provided in the control room, and constitute an infrastructure-side traffic control system with the central device.
As shown in FIG. 2, the optical beacon 2 is installed at a location away from the stop line P of the intersection 5 on the road W by a certain distance upstream, and the vehicle-mounted device 4 is optically communicated using near infrared rays as a communication medium. Two-way communication with. Moreover, the traffic signal 3 is installed in the intersection 5 of the road W, and bidirectional | two-way communication is possible between the vehicle-mounted apparatuses 4 by the radio | wireless communication which used the electromagnetic wave as the communication medium.

[Configuration of optical beacon]
As shown in FIG. 1, the optical beacon 2 includes a communication unit 6 that is a communication interface connected to a central device via a communication line such as a telephone line, a beacon controller 7 to which the communication unit 6 is connected, A plurality of beacon heads (projectors and receivers) 8 connected to the sensor interface of the beacon controller 7 are provided.
As shown in FIGS. 2 and 3, the beacon head 8 is attached to an erection bar that is erected horizontally on the road W side from a column 9 erected on the side of the road. Further, the beacon controller 7 has a function as a control unit that collectively controls the beacon head 8 and is installed in the support column 9.

The beacon controller 7 includes a programmable microcomputer having a CPU, a memory (RAM), a storage device (ROM), and the like, and performs bidirectional communication with the central device by the communication unit 6 (FIG. 1) and an in-vehicle device by the beacon head 8. 4 has a function of performing road-to-vehicle communication with 4.
The beacon head 8 is configured by housing a light-emitting unit made of a light-emitting diode or the like and a light-receiving unit made of a photodiode or the like in a casing, and the light-emitting unit narrows down the downlink information 11 made of near-infrared light on the road W. Light is emitted to the regional communication area, and the light receiving unit receives the uplink information 11 made up of near-infrared light from the in-vehicle device 2 of the vehicle C passing through the narrow communication area.

The downlink information 10 transmitted by the optical beacon 4 includes lane notification information including vehicle ID, traffic jam information, section travel time information, and event regulation information, and for safe driving support for the driver of the vehicle C. As support information to be used, a current position (beacon passage position) P0 of the vehicle C when the optical beacon 2 passes and an error upper limit R0 included in the passage position P0 are included.
Specifically, the beacon passage position P0 of the vehicle C is made up of the position coordinates of a specific point in the narrow communication area. The error upper limit R0 is an upper limit value of an error that can occur in the position coordinates, and this upper limit value is a specific set value that is determined in advance by a communication delay in the optical beacon 2 or the like.
The error setting value of the beacon passage position P0 is not limited to the error upper limit R0, but may be a value obtained by multiplying the error upper limit R0 by a constant less than 1, or an error average value. .

  The beacon controller 7 stores the beacon passage position P0 composed of the position coordinates and the error upper limit R0 in the downlink information 10 for the in-vehicle device 4 of the vehicle C passing through the narrow area communication area. Is transmitted to the beacon head 8 and the in-vehicle head 27 of the in-vehicle device 4 receives the downlink information 10.

[Configuration of traffic signal]
As shown in FIG. 1, the traffic signal 3 includes a communication unit 13 that is a communication interface connected to a central device via a communication line such as a telephone line, a signal controller 14 to which the communication unit 13 is connected, A wireless communication device 15 connected to the wireless communication interface of the signal controller 14 and a signal lamp 16 whose lamp color is switched and controlled by the signal controller 14 are provided.
As shown in FIG. 2 and FIG. 3, the signal lamp 16 is attached to the upper end portion of the column 17 erected at the intersection 5. The signal controller 14 has a function as a control unit that collectively controls the signal switching timing of the signal lamp device 16, and is installed in the column 17.

The signal controller 16 includes a programmable microcomputer having a CPU, a memory (RAM), a storage device (ROM), and the like. The signal controller 16 communicates with the central device by the communication unit 13 and the in-vehicle device 4 by the wireless communication device 15. It has a function to perform road-to-vehicle communication.
The communication information wirelessly transmitted by the traffic signal 3 includes the signal switching timing ts for one cycle of the signal controller 14 and the stop line P on the road W as support information used for safe driving support for the driver. The position coordinates (stop position) Xp, the position coordinates of the interpolation point on the road W, and the like are included.

[Configuration of in-vehicle device and vehicle]
As shown in FIG. 1, a vehicle C according to this embodiment includes a vehicle body 19 having a driver's seat (not shown), the in-vehicle device 4 mounted on the vehicle body 19, and each part of the vehicle C. An electronic control unit (ECU) 20 that drives the vehicle body 19, a brake device 2 that brakes the vehicle body 19, and a speed detector 23 that constantly detects the current speed of the vehicle C. .
The ECU 20 performs various controls on the vehicle C such as drive control of the engine 21 based on the accelerator operation of the driver and braking control based on the brake operation.

  The in-vehicle device 4 is connected to the in-vehicle computer 24 constituting the safe driving control device of the present embodiment, the wireless communication device 25 connected to the wireless communication interface of the computer 24, and the sensor interface of the computer 24. A position detector 26 that constantly detects the current position of the vehicle C based on a moving distance from the immediately preceding position and a change in azimuth, and an interface for the sensor. The vehicle-mounted head (projector / receiver) 27, a timepiece device 28 including a radio timepiece having a time correction function, a display 29 and a speaker device 30 as a human interface for a driver of a passenger seat are provided.

The on-vehicle head 27 includes a light emitting diode (LED) and a photodiode (not shown), like the beacon head 8 of the optical beacon. Among these, the light emitting diode emits uplink information 11 made of near infrared light, and the photodiode receives downlink information 10 made of near infrared light emitted in the narrow communication area.
The in-vehicle computer 24 includes a programmable microcomputer having a CPU, a memory (RAM), and a storage device (ROM). The in-vehicle head 27 communicates with the optical beacon 2 by the in-vehicle head 27 and wirelessly communicates with the traffic signal device 3 by the wireless communication device 25. Performs communication control processing.

  Moreover, the vehicle-mounted computer 24 has stored the program which performs each predetermined function in a memory | storage device, and until the vehicle C reaches | attains the stop line P from the passage of the optical beacon 2 as a function part which this program performs. A calculation unit 31 that calculates an expected required time, a determination unit 32 that determines whether it is dangerous to enter the intersection 5 based on the calculated estimated required time, and a safe driving for the driver based on the determination result And an urging support control unit 33. The processing contents of these functional units 31, 32, and 33 will be described later.

Further, the in-vehicle computer 24 determines how the error upper limit R of the current position measured by the vehicle C changes from the error upper limit R0 at P0 provided from the optical beacon 2 at the beacon passage position P0 according to the passage of time after the vehicle travels. An error upper limit variation function 34 is stored in the storage device.
For example, as shown in FIG. 4, the error upper limit variation function 34 is stored in a storage device as a lookup table 35, and the in-vehicle computer 24 acquires the passage position P 0 from the optical beacon 2 (positioning correction time). The table 35 is referred to using the elapsed time Δt from) as an input value, and the error upper limit R, which is an output value corresponding to the elapsed time Δt, is obtained from the lookup table 35.

The error upper limit variation function 34 (y = R (Δt)) has an error upper limit R0 provided from the optical beacon 4 as an initial value, and gradually increases with the elapsed time Δt in a range from the initial value to a predetermined maximum value Rmax. When Δt = ∞, it is defined to converge to its maximum value Rmax. This variation function 34 represents the degree of error expansion with respect to the travel time of the vehicle C, and is specifically obtained by a travel experiment or the like. When the current position of the vehicle C is measured by inertial navigation based on the immediately preceding position coordinates, an error is accumulated as the vehicle travels, so the error upper limit variation function 34 (y = R (Δt)) is an increase function of Δt. It becomes.
The error upper limit variation function 34 (y = R (Δt)) can be defined by a mathematical expression such as a polynomial other than the lookup table 35. Further, the error upper limit variation function 34 (y = R (Δt)) can be defined not as a function of the elapsed time Δt but as a function of the movement distance Δx from the passing position P0 acquired from the optical beacon 2. This movement distance Δx can be measured by the position detector 26, for example.

[Processing content of in-vehicle computer]
[Danger Judgment Processing]
FIG. 4 is a flowchart showing a risk determination process performed by the in-vehicle computer 24.
The in-vehicle computer 24 performs the risk determination process shown in FIG. 4 at a predetermined calculation cycle (for example, 0.1 second cycle), and updates the current error upper limit R for each cycle while predicting the required time to the stop line P. T1 and T2 are calculated and a risk determination is performed. Hereinafter, this risk determination process will be described.

  As shown in FIG. 4, first, the in-vehicle computer 24 determines whether or not the position coordinates (current position of the vehicle C when the beacon passes) P0 included in the downlink information 10 from the optical beacon 2 is received ( Step S1) If it is received, its own current position is corrected to the received position coordinate P0 (Step S2), and the current time is stored in the memory as a positioning correction time (Step S3).

On the other hand, since the position coordinate (current position of the vehicle C when the beacon passes) P0 included in the downlink information 10 from the optical beacon 2 is not received in the period other than when the optical beacon 2 passes, the position detector 26 (The current position of the vehicle C measured by inertial navigation based on the immediately preceding position coordinates) is set as the current position Pc of the vehicle C (step S3 ′), and the process proceeds to the next step.
Next, the calculation unit 31 of the in-vehicle computer 24 calculates the distance L to the stop line P based on the current position Pc of the vehicle C and the position coordinates Xp of the stop line P acquired from the traffic signal 3 (Step S31). S4) The current traveling speed V of the vehicle C is acquired from the speed detector 23 (step S5).

Further, the calculation unit 31 of the in-vehicle computer 24 uses the time difference (= elapsed time from the positioning correction time) Δt between the current time and the positioning correction time as an input value, and the variation function of the lookup table 35 stored in the storage device. 34, the error upper limit R of the current positioning after the positioning correction time is determined (step S6). If the position coordinate P0 has not been received from the optical beacon 2 during traveling, Δt = ∞ is set, so that the error upper limit R is Rmax.
And the determination part 32 of the vehicle-mounted computer 24 determines whether the following inequality (1) is materialized (step S7).

L> R + τV + V ² / 2d (1)
In the inequality (1), τ is a margin time (seconds) until the driver who has received the alarm starts to decelerate, and is normally held in the storage device as a constant of 2 to 4 seconds. D is the deceleration of the vehicle C, and is normally held in the storage device as about 0.3 g (g is gravitational acceleration). If the above inequality (1) holds, it is recognized that the vehicle C has a sufficient distance L to stop at the stop line P. In this case, the approach to the intersection 5 is not determined as dangerous, and the first Return to step S1.

On the other hand, when the inequality (1) is not satisfied, the calculation unit 31 of the in-vehicle computer 24 calculates the speed detector 23 by subtracting the error upper limit R from the distance L from the current position Pc of the vehicle C to the stop line P. Is divided by the current travel speed V obtained from the above, to calculate a minimum estimated required time T1 to the stop line P (step S8).
That is, the calculation unit 31 of the in-vehicle computer 24 calculates the minimum estimated required time T1 by the following equation (2).
T1 = (LR) / V (2)

2 and 3 show a time axis t of positioning correction time with an arbitrary time point as the origin (t = 0), and this time axis t is drawn extending vertically upward from the stop line P. . On this time axis t, the signal switching timing ts is written together. At the timing ts, the green signal time G indicated by a single solid line, the red signal time S indicated by a double line, and the yellow indicated by a jagged line. A signal time Y is included.
2 and 3, the estimated required time Tc to reach the stop line P when the travel distance from the current position Pc of the vehicle C to the stop line P is L without considering the positioning error is as follows: It can be calculated by L / V.

When the error upper limit R of the current position Pc of the vehicle C acts forward (downstream of the road W), the actual travel distance after passing through the optical beacon 2 is LR (P1 to P1). In this case, the estimated required time T1 to reach the stop line P is calculated as (LR) / V.
Conversely, when the error upper limit R of the current position Pc of the vehicle C acts backward (upstream of the road W), the actual travel distance from the current position of the vehicle C to the stop line P is L + R (P2 to P In this case, the estimated required time T2 to reach the stop line P is calculated as (L + R) / V.

  Then, as shown in FIG. 2, at the arrival time tc after the estimated required time Tc without taking the positioning error into account, even when the vehicle C arrives at the green signal time G, the positioning of the current position Pc of the vehicle C is determined. Since the error acts backward (upstream side) and the actual vehicle C is at the point P2 behind the current position Pc, the yellow signal time Y and the red signal time S are reached at the actual arrival time t2. In such a case, although the approach to the intersection 5 should be determined to be dangerous, it is not determined as such.

  On the other hand, as shown in FIG. 3, at the arrival time tc after the estimated required time Tc without considering the positioning error, even when the vehicle C arrives at the green signal time G, the positioning of the current position Pc of the vehicle C is determined. Since the error acts forward (downstream) and the actual vehicle C is at a point P1 ahead of the current position Pc, there may be a red signal time S at the actual arrival time t1. Even in such a case, the approach to the intersection 5 should not be judged as such although it should be judged as dangerous.

Therefore, the determination unit 32 of the in-vehicle computer 24 first determines the signal light at the intersection 5 when the minimum predicted required time T1 elapses (time t1 in FIG. 3) based on the signal switching parameter ts acquired from the traffic signal device 3. It is determined whether or not the color is blue (step S9).
If the determination is negative, for example, as shown in FIG. 3, it is considered that the red signal time S is still reached at the elapsed time t1 of the minimum predicted required time T1, and in this case, The determination unit 32 determines that the approach to the intersection 5 is dangerous, and outputs the determination result (step S11).

Next, when the signal lamp color at the intersection 5 is blue in step S9, the determination unit 32 of the in-vehicle computer 24 further determines the remaining time of the green signal time G when the minimum estimated required time T1 has elapsed. It is determined whether or not an error time range (= 2R / V) that is a time difference between the elapsed time t1 of the minimum predicted required time T1 and the elapsed time t2 of the maximum predicted required time T2 (step S10).
That is, it is determined whether or not the time (= 2R / V) from t1 to t2 is included in the green light time G at the intersection 5.

If the above determination is negative, for example, as shown in FIG. 2, it is considered that the yellow signal time Y or the red signal time S is already reached at the time t2 when the maximum estimated required time T2 has elapsed. Also in this case, the determination unit 32 determines that the approach to the intersection 5 is dangerous, and outputs the determination result (step S11).
If the above determination is correct, the approach to the intersection 5 is not determined as dangerous, and the process returns to the first step S1 (step S10).

  As described above, the error time range (= 2R / V) is the difference between the maximum predicted required time T2 and the minimum predicted required time T1, that is, the relationship of T2 = T1 + 2R / V is established. In step S10 in FIG. 4, it is also determined at the same time whether or not the signal lamp color at the time t2 when the maximum estimated required time T2 has elapsed is blue.

  In the flowchart shown in FIG. 4, first, it is determined whether the signal lamp color at the time t1 when the minimum predicted required time T1 has elapsed is blue (step S9), and then the remaining time of the green signal time G at the elapsed time t1. Is determined to be greater than or equal to the error time range (= 2R / V) (step S10), conversely, it is determined whether or not the signal lamp color at t2 when the maximum estimated required time T2 has elapsed is blue. Then, it may be determined whether or not the elapsed time of the green light time G at the elapsed time t2 is equal to or greater than the error time range (= 2R / V).

In the above risk determination process, all cases where the vehicle arrives at the intersection 5 at the yellow signal time Y are determined to be dangerous. However, a grace time ΔY (0 <ΔY <Y) is set in advance, and the yellow signal time Y is determined. Of these, the first half ΔY may not be determined as dangerous, and the second half Y−Δ may be determined as dangerous.
In this case, the time obtained by adding ΔY of the first half of the yellow signal to the original green signal time G may be considered as the green signal time, and the remaining time Y−ΔY may be considered as the yellow signal time.

[Support control processing]
The support control unit 33 of the in-vehicle computer 24 performs the following safe driving support for the driver based on the result of the risk determination by the determination unit 32.
That is, the support control unit 32 that has received the risk determination output from the determination unit 32 stops, for example, before the stop line P from the distance L to the stop line P and the current traveling speed V of the vehicle C. Is calculated, and the ECU 20 is notified of the deceleration. The ECU 20 operates the brake device 22 so as to achieve the deceleration, whereby the vehicle C can be automatically stopped before the stop line P.

Further, the support control unit 33 alerts (warns) the driver using the display 29 and the speaker device 30.
For example, the distance L to the stop line P may be displayed on the display 29 by the support control unit 33. Further, when the current traveling speed V of the vehicle C is too high, the support controller 33 displays a warning to stop or slow down on the display 29, or outputs the warning from the speaker device 30 by voice. May be.

In order to brake the vehicle C automatically or maintain the speed, the support control unit 32 may directly control the brake device 24 (FIG. 5) and the accelerator of the vehicle C. 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.
Further, the support control unit 32 may perform not only the control led by the in-vehicle device 4 but also an operation for assisting the driving operation of the driver such as a brake assist.

  The support control unit 32 may notify the driver of the vehicle C of the result of signal light color estimation by voice or image information. For example, sound such as “Since the signal will change soon and should be stopped” is emitted from the speaker device 30 to the driver, or displayed on the display 29 such as a head-up display or a navigation device with characters or designs. Can do.

  According to the safe driving support system 1 of the present embodiment, the in-vehicle computer 24 considers the error upper limit R of the current position Pc of the vehicle C, and the minimum estimated required time T1 and the maximum estimated required time to the stop line P. T2 is calculated, and it is determined whether or not the approach to the intersection 5 is dangerous based on the signal switching timing ts at the time t1 and t2 when the predicted required times T1 and T2 have elapsed. Even if there is, the estimated required time to the stop line P is not estimated longer or shorter than actual. For this reason, it is possible to prevent a “warning leak” that is not warned by the driver even though it is determined that the approach to the intersection 5 is dangerous.

Further, according to the safe driving support system 1 of the present embodiment, the in-vehicle computer 24 does not use the error upper limit R0 provided from the optical beacon 2 as it is, but has an error upper limit that changes corresponding to the elapsed time Δt. Since the error upper limit R is determined based on the fluctuation function 34 (y = R (Δt)), the error upper limit R can be as close as possible to the actual positioning error.
For this reason, compared with the case where the error upper limit R is set to a fixed value, it is possible to prevent a situation in which a “false warning” is issued on the contrary, and to improve the determination accuracy.

[Other Embodiments]
The present invention is not limited to the above embodiment.
For example, the signal switching timing ts acquired by the in-vehicle device 4 may be acquired not from the traffic signal device 3 but from the downlink information 10 of the optical beacon 2 or may be acquired from other roadside devices.
Further, the position coordinates P0 and the error information R0 acquired by the vehicle C from the infrastructure side may be acquired from the wireless communication device 15 of the traffic signal 3 instead of from the optical beacon 2, or from other roadside devices. May be.

The position coordinate P0 of the vehicle C is as long as the positioning accuracy is higher than that of a positioning device that the vehicle C normally has (for example, a wheel speed sensor, a direction sensor, and a position detector such as GPS). The measurement can also be performed by a device other than the optical beacon 2.
For example, as a positioning device that detects the position coordinate P0 of the vehicle C with high accuracy, a device that detects a passing point of the vehicle C with a magnetic nail or a certain process is added to the image data of the vehicle C taken by a camera. It is also possible to employ one that detects the position coordinates of the vehicle C, or RTK-GPS (Real Time Kinematic GPS) that accurately measures the position coordinates of the moving point relative to the reference point in real time using GPS technology.

Further, in the above embodiment, the error upper limit R is determined based on the error upper limit variation function 34 that changes in accordance with the elapsed time Δt. Instead, for example, a GPS device included in the vehicle C is used. The error upper limit R can also be determined using the calculated error estimated value.
That is, when the positioning device of the vehicle C is a GPS device, a horizontal accuracy of precision (HDOP) and a user equivalent ranging error (UERE: User Equivalent) that can be calculated at a fixed positioning cycle in the GPS receiver. By multiplying the product of (Ranging Error) by 2, the estimated error value at the time of reception can be obtained.

Therefore, for example, multiplying the estimated error value dynamically calculated by the GPS receiver by a constant, or using a lookup table that defines the correspondence between the estimated error value and the error setting value. Thus, the error upper limit R can be determined.
Even when the error setting value is determined according to the error estimation value dynamically calculated by the GPS receiver in this way, the error setting value can be made as close as possible to the actual positioning error, and the error setting value can be kept constant. Compared with the case where the set value is used, it is possible to prevent the occurrence of a “false warning” on the contrary.

It is a block diagram which shows the whole structure of a safe driving assistance system. It is a block diagram of the road which shows the whole structure of a safe driving system. It is a block diagram of the road which shows the whole structure of a safe driving system. It is a flowchart which shows the danger determination process which a vehicle-mounted computer performs.

Explanation of symbols

1 Safe driving support system 2 Optical beacon (roadside device)
3 traffic lights (roadside equipment)
4 On-vehicle device 5 Intersection 6 Communication unit 7 Beacon controller 8 Beacon head (transmission unit)
10 Downlink Information 11 Uplink Information 14 Signal Controller 15 Wireless Communication Device (Transmitter)
16 Signal lamp 23 Speed detector 24 On-board computer (safe driving support device)
25 Wireless communication device (reception unit, acquisition unit)
26 Position detector (positioning device)
27 On-vehicle head (reception unit, acquisition unit)
31 Calculation unit 32 Judgment unit 33 Support control unit 34 Fluctuation function 35 Look-up table W Road C Vehicle P Stop line P0 Position coordinates when passing beacon (high-precision current position)
R0 Error upper limit when passing beacon Pc Current position of vehicle R Error upper limit (error set value)
V Traveling speed ts Signal switching timing Xp Stop line position coordinates (stop position)

Claims (9)

A safe driving support device that determines whether or not a vehicle traveling on a road toward an intersection is dangerous to enter the intersection and issues a warning to the driver of the vehicle when it is dangerous,
An acquisition unit that acquires the signal switching timing of the intersection, information on a distance between the current position of the vehicle and a stop position before the intersection, an error setting value of the current position, and a traveling speed of the vehicle;
A calculation unit that calculates a maximum estimated required time to the stop position based on information on a distance between the current position of the vehicle and the stop position, an error setting value of the current position and a travel speed of the vehicle;
A safe driving support apparatus, comprising: a determination unit that determines whether or not the approach to the intersection is dangerous based on the signal switching timing when the maximum predicted required time has elapsed. The calculation unit further calculates a minimum estimated required time to the stop position based on information on a distance between the current position of the vehicle and the stop position, an error setting value of the current position, and a traveling speed of the vehicle. Calculate
The safe driving support device according to claim 1, wherein the determination unit further determines whether or not the approach to the intersection is dangerous based on the signal switching timing when the minimum predicted required time has elapsed. The acquisition unit is capable of acquiring a high-precision current position of the vehicle measured with higher accuracy than a positioning device that the vehicle normally has,
The safe driving support device according to claim 1 or 2, wherein the calculation unit determines the error setting value according to an elapsed time after passing through the high-precision current position or a movement distance from the high-precision current position.   The safe driving support device according to claim 1, wherein the calculation unit determines the error setting value according to an error estimated value calculated using a positioning device included in the vehicle.   The determination unit determines whether or not the signal lamp color of the intersection is blue at the time of any one of the elapsed time of the maximum predicted required time and the elapsed time of the minimum predicted required time, and one of them 3. It is determined whether or not it is dangerous to enter the intersection by determining whether or not a time between the reference time of the first time and the other reference time is included in the green light time at the intersection. Safe driving support device.   The safe driving support apparatus according to claim 3, wherein the acquisition unit acquires the high-precision current position based on downlink information from an optical beacon installed on the road. A safe driving support system including an in-vehicle device of a vehicle traveling on a road and a roadside device capable of communicating with the in-vehicle device,
The roadside device is
A signal transmission timing of the intersection, information on a distance between the current position of the vehicle and a stop position before the intersection, and a transmission unit that transmits the set value of the current position to the in-vehicle device,
The in-vehicle device is
A receiver for receiving information from the transmitter;
A calculation unit that calculates a maximum estimated required time to the stop position based on information on a distance between the current position of the vehicle and the stop position, an error setting value of the current position and a travel speed of the vehicle;
A determination unit for determining whether it is dangerous to enter the intersection based on the signal switching timing at the time of the maximum predicted required time;
A safe driving support system comprising: a support control unit that issues a warning to a driver of the vehicle when it is determined as dangerous. A computer program for causing a computer to execute determination processing for determining whether or not a vehicle traveling on a road toward an intersection is dangerous to enter the intersection,
Obtaining the signal switching timing of the intersection, the information on the distance between the current position of the vehicle and the stop position before the intersection, the error setting value of the current position, and the traveling speed of the vehicle;
Calculating a maximum estimated required time to the stop position based on information on a distance between the current position of the vehicle and the stop position, an error setting value of the current position and a travel speed of the vehicle;
And determining whether or not it is dangerous to enter the intersection based on the signal switching timing when the maximum estimated required time has elapsed. A safe driving support method for determining whether or not a vehicle traveling on a road toward an intersection is safe to enter the intersection and issuing a warning to a driver of the vehicle when it is dangerous,
Obtaining the signal switching timing of the intersection, the information on the distance between the current position of the vehicle and the stop position before the intersection, the error setting value of the current position, and the traveling speed of the vehicle;
Calculating the maximum estimated required time to the stop position based on the information on the distance between the current position of the vehicle and the stop position, the error setting value of the current position and the traveling speed of the vehicle;
A safe driving support method, wherein it is determined whether or not it is dangerous to enter the intersection based on the signal switching timing when the maximum predicted required time has elapsed.

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