JP2000172998A - Inter-vehicle distance determination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inter-vehicle distance determination device which can determine the most suitable inter-vehicle distance in accordance with the traffic condition. SOLUTION: The frequency with which other vehicles cut in between user's own vehicle and a vehicle running ahead of it (the number of vehicles cut in between them) is counted (S201). Inter-vehicle distances on lanes adjacent to the lane where user's own vehicle is running are calculated (S203). It is judged whether a traffic jam has occurred or not based on the frequency of cut-in vehicles and inter-vehicle distances on adjacent lanes, and the most suitable inter-vehicle distance L1 for running of user's own vehicle is calculated based on the judged result (205).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance determining apparatus, and more particularly to an inter-vehicle distance determining apparatus mounted on a vehicle and used for determining an optimal inter-vehicle distance with a preceding vehicle.

[0002]

2. Description of the Related Art For example, Japanese Patent Laying-Open No. 7-123534 discloses an inter-vehicle distance control device including a means for inputting surrounding image information, a radar means, and a driver operation input means. This device determines an optimum headway by recognizing a surrounding situation from image information.

This publication also discloses a technique for controlling the following distance according to the driving skill of the driver, controlling the optimum following distance based on the frequency of braking of the preceding vehicle, whether or not a beginner's mark is attached, and the fluctuation of the preceding vehicle. A technique for performing this is disclosed.

[0004]

However, the technology disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Hei 7-123534 is based on the image processing, which is used to determine the wobble of another vehicle, the presence or absence of a beginner's mark, the frequency of use of brakes, and the like. This was a requirement, and the optimum inter-vehicle distance could not be determined according to the traffic situation.

In Japanese Patent Application Laid-Open No. Hei 7-123534, the surrounding situation is recognized by image processing. A great deal of information can be obtained from an image, but this depends on the processing capability of the image information of the apparatus, and there is a problem in that performing many processes leads to an increase in processing time and cost.

Accordingly, it is a first object of the present invention to provide an inter-vehicle distance determining apparatus capable of determining an optimum inter-vehicle distance according to traffic conditions.

A second object of the present invention is to provide an inter-vehicle distance determining apparatus capable of determining an optimum inter-vehicle distance without relying on image information.

[0008]

According to one aspect of the present invention, there is provided an inter-vehicle distance determining apparatus, comprising: an inter-vehicle distance determining apparatus which divides a distance between another vehicle and a vehicle traveling in front of the own vehicle; Detecting means for detecting that the vehicle has been trapped; and determining means for determining an optimum inter-vehicle distance based on a detection result of the detecting means. Preferably, the detection means performs the detection using a radar.

According to another aspect of the present invention, an inter-vehicle distance determining apparatus includes a measuring means for measuring an inter-vehicle distance of a vehicle in a lane adjacent to a lane in which the own vehicle travels, and a self-vehicle distance determining device based on the measured inter-vehicle distance. Determining means for determining an optimum inter-vehicle distance of the vehicle. Preferably, the measurement means performs the measurement using a radar.

According to still another aspect of the present invention, an inter-vehicle distance determining apparatus includes a storage unit for storing a standard travel time of a predetermined section, a measuring unit for measuring an actual travel time of a predetermined section, and a storage unit. Deciding means for deciding an optimum inter-vehicle distance based on the determined travel time and the measured travel time.

[0011] According to still another aspect of the present invention, an inter-vehicle distance determining apparatus includes an obtaining means for obtaining traffic information by communication, and a determining means for determining an optimum inter-vehicle distance based on the obtained traffic information. .

[0012] Preferably, the inter-vehicle distance determining apparatus further includes an adjusting means for adjusting an optimum inter-vehicle distance by an input from a driver.

According to these inventions, it is possible to provide an inter-vehicle distance determining apparatus capable of determining an optimum inter-vehicle distance according to traffic conditions.

Further, when the detection is performed using the radar, it is possible to provide an inter-vehicle distance determining apparatus capable of determining an optimum inter-vehicle distance without relying on image processing.

[0015]

[First Embodiment] FIG. 1 is a block diagram showing a configuration of an inter-vehicle distance control device using an inter-vehicle distance determination device according to a first embodiment of the present invention.
This inter-vehicle distance control device includes four tires W ₁ , W ₂ , W ₃ , W ₄ (provided that tires W ₁ ,
W ₂ corresponds to the front left and right tires, respectively, W _3, W ₄ correspond to right and left rear tires. Also, when collectively referred to below,
It is called "tire _Ti ". ) Is provided with a conventionally known wheel speed sensor 1 functioning as a rotational angular speed detecting means or the like provided in connection with each of the above. The output of the wheel speed sensor 1 is given to the control unit 2. The control unit 2 controls a scanning laser radar 6 that scans a thin laser beam to the left and right to recognize an inter-vehicle distance to a plurality of vehicles ahead and a direction in which the vehicles exist, and controls the speed of the vehicles. A throttle actuator 7 for maintaining a safe inter-vehicle distance, a warning device 8 for generating a warning when the preceding vehicle suddenly decelerates or an obstacle exists in the traveling direction of the vehicle, a current position of the vehicle and an intersection. A navigation system 11 for obtaining the position of the vehicle, a road-to-vehicle communication unit 12 for obtaining traffic information by road-to-vehicle communication, and a brake control unit 13 for controlling the brake to brake the vehicle are connected.

The control unit 2 is connected to an input unit 10 for adjusting an optimum inter-vehicle distance by an input from a driver. The navigation system 11 stores a standard travel time of a predetermined section.

FIG. 2 is a block diagram showing the electrical configuration of the following distance control device. The control unit 2 includes an I / O interface 2a necessary for transmitting and receiving signals to and from an external device, a CPU 2b functioning as a center of arithmetic processing, a ROM 2c storing a control operation program of the CPU 2b, and C
It is configured by a microcomputer including a RAM 2d from which data and the like are temporarily written when the PU 2b performs a control operation, and from which the written data and the like are read.

[0018] In the wheel speed sensor 1, a pulse signal corresponding to the number of revolutions of the tire W _i (hereinafter referred to as "wheel speed pulse")
Is output. The CPU 2b calculates the rotational angular speed F _i of each tire W _i at every predetermined sampling period ΔT (sec) (for example, ΔT = 1) based on the wheel speed pulse output from the wheel speed sensor 1.

FIG. 3 is a block diagram showing the configuration of the scanning laser radar 6. Referring to the figure, a scanning laser radar 6 includes a light transmitting unit 6a including a laser diode for transmitting light to a forward object, and a light receiving unit for receiving light reflected from the forward object. 6c, and a motor 6b for controlling the direction of the light transmitting unit 6a to scan a forward object by the light transmitting unit 6a.

In the present embodiment, the motor 6
b, the object in front of the vehicle is scanned. Alternatively, the scanning may be performed by moving the light receiving unit 6c with a motor. Alternatively, a plurality of light transmitting units having different light transmitting directions may be provided and switched. The scanning may be performed by turning on the light. Alternatively, scanning may be performed by providing a plurality of light receiving units having different light receiving directions and switching between them for use.

FIG. 4 is a diagram showing the appearance of the input unit 10. As shown in FIG. Referring to the drawing, input unit 10 is attached to a steering wheel of a vehicle. The input unit 10 is used for setting a preceding vehicle following travel mode and adjusting the inter-vehicle time.

The preceding vehicle following mode is a mode in which the preceding vehicle is followed while maintaining a predetermined inter-vehicle distance with the preceding vehicle by automatically controlling the throttle and the like.

The inter-vehicle time is the time required for the vehicle to proceed to the position of the vehicle in front (that is, the time required for the vehicle to collide when the vehicle in front stops suddenly). The following relationship holds between the following distance, the speed of the own vehicle, and the inter-vehicle time: (inter-vehicle distance) = (self-vehicle speed) × (inter-vehicle time). If the inter-vehicle time is the same, control is performed such that the inter-vehicle distance increases as the speed of the vehicle increases.

In FIG. 4, the input unit 10 includes a setting switch 57 for setting a preceding vehicle following mode, an inter-vehicle time increasing switch 55 for increasing the inter-vehicle time, and an inter-vehicle time decreasing for decreasing the inter-vehicle time. Switch 53,
A cancel switch 51 is provided for canceling the adjustment by the input unit 10 and automatically determining the optimum inter-vehicle distance.

The inter-vehicle time increases or decreases in proportion to the time during which the inter-vehicle time increase switch 55 or the inter-vehicle time decrease switch 53 is pressed. The driver sets the inter-vehicle time increase switch 5
When the user releases the switch 5 or the inter-vehicle time reduction switch 53, the inter-vehicle time at that time is stored, and traveling based on the inter-vehicle time is performed. This allows the driver to finely adjust the inter-vehicle time.

When the cancel button 51 is pressed, the stored inter-vehicle time is cancelled, the optimum inter-vehicle time is automatically obtained, and the mode is shifted to a mode for running based on the optimum inter-vehicle time.

FIG. 5 is a flowchart showing the operation of the control unit 2. Referring to the figure, initialization is performed in step S1. In this initial setting, the switch flag is set to “0”.

In step S3, the setting switch 57
It is determined whether or not the preceding vehicle following travel mode is set. If YES, the input unit 10 is entered in step S5.
, Or whether the switch flag is “1”. If YES, a process of setting an inter-vehicle distance is performed based on a switch operation in step S7.

On the other hand, if "NO" in the step S5, a process of automatically calculating the optimum inter-vehicle distance L1 from the surrounding situation is performed in a step S9.

In step S11, the scanning laser radar 6 detects the distance to the vehicle ahead in the own lane. In step S13, it is determined whether the distance to the vehicle in front (ie, the inter-vehicle distance) is appropriate. If NO, a warning using the warning device 8 or a speed control using the throttle actuator 7 and the brake control unit 13 is performed in step S15, and the process returns to step S3.

On the other hand, if "YES" in the step S13, the process returns to the step S3. FIG. 6 is a flowchart showing the content of the inter-vehicle distance setting process (S7) based on the switch operation of FIG.

Referring to the figure, the switch flag is set to "1" in step S101. Next, in step S103, it is determined what the contents of the switch operation are.

The switch operation is an inter-vehicle time increase switch 55
If so, the inter-vehicle time is increased within a predetermined range in step S105. If the switch operation is performed by the inter-vehicle time reduction switch 53, the inter-vehicle time is reduced within a predetermined range in step S107. If the switch operation is performed by the cancel switch 51, step S1
At 09, the switch flag is set to "0". If there is no input from the switch, the process proceeds to step S111 without doing anything.

In step S111, an inter-vehicle distance L1 to be protected is calculated based on the set inter-vehicle time and the own vehicle speed V (which is obtained by the wheel speed sensor 1).

FIG. 7 is a flowchart showing the content of the optimum inter-vehicle distance L1 calculation process (S9) in FIG. Referring to the figure, in step S201, the number of times (the number of interrupted vehicles) that another vehicle has interrupted between the own vehicle and the vehicle traveling in front of it is counted. In step S203,
The calculation of the inter-vehicle distance (inter-vehicle distance between adjacent lanes) in the lane adjacent to the lane in which the own vehicle travels is performed. In step S205, the inter-vehicle time is obtained from the number of interrupted vehicles per unit time and the average of the inter-vehicle distances of adjacent lanes within a predetermined time. Then, the optimum inter-vehicle distance L1 is calculated from the speed V of the own vehicle and the inter-vehicle time.

Specifically, when the number of interrupted vehicles is large or when the distance between adjacent lanes is short, there is a high possibility that congestion has occurred. The optimum inter-vehicle distance L1 is shortened in order to prevent another vehicle from intervening with the present vehicle.

Conversely, when the number of interrupted vehicles is small and the inter-vehicle distance between adjacent vehicles is long, the optimum inter-vehicle distance L1 is increased.

FIG. 8 is a flowchart showing the interrupt vehicle counting process (S
It is a flowchart which shows the content of 201). Referring to the figure, in step S301, it is determined whether a predetermined time has elapsed since the preceding vehicle following travel mode was set.
This is to stop counting the number of interrupted vehicles until the own vehicle follows the preceding vehicle.

If YES in step S301, the distance L to the preceding vehicle is acquired by using the scanning laser radar 6 in step S303. If the preceding vehicle was running smoothly, the distance L should have been equal to the optimum inter-vehicle distance L1.

In step S305, it is determined whether L <L1. If YES, the number of interrupted vehicles is counted by one in step S307 to indicate that there was an interrupted vehicle between the preceding vehicle and the own vehicle during the preceding vehicle following travel mode. Thereafter, in step S309, it is determined whether or not the speed V of the own vehicle is higher than the speed of the interrupting vehicle. YE
If it is S, there is a possibility of a rear-end collision with the interrupted vehicle, so that a warning using the warning device 8 is issued in step S311.

On the other hand, if NO in step S301, S305 or S309, the process returns to the main routine.

FIG. 9 is a flowchart showing the contents of the inter-vehicle distance calculation processing (S203) of the adjacent lane in FIG. This flowchart detects the occurrence of traffic congestion by calculating the inter-vehicle distance in the lane next to the lane in which the vehicle is traveling.

Referring to FIG. 9, in step S401, the scanning laser radar 6 detects a vehicle in an adjacent lane. Specifically, detection of a vehicle in an adjacent lane at a distance X [m] is performed. It is determined in step S403 whether a vehicle is present. If YES, step S40
At 5, it is determined whether the relative speed of the vehicle in the adjacent lane is positive. Here, a positive relative speed indicates a case where the speed of the vehicle in the adjacent lane is higher than that of the own vehicle.

If YES in step S405, the relative speed of the vehicle is substituted for variable V1 in step S407. In step S409, the current time is substituted for a variable T2.

In step S411, it is determined whether a vehicle in the adjacent lane has been detected in the past. If YES, the inter-vehicle distance in the adjacent lane is determined in step S413 as V1 × (T2-T1).

In step S415, variable T2 is substituted for variable T1. If “NO” in the step S403 or S405, the process returns to the main routine.

If "NO" in the step S411, the process proceeds to a step S415. FIG. 10 is a flowchart showing step S401 in FIG.
FIG. 7 is a diagram for explaining a method of determining a distance X [m] in the embodiment. When detecting a vehicle in an adjacent lane, it is preferable to detect a vehicle that is close to the own vehicle in consideration of shadowing by another vehicle.

Referring to the figure, it is assumed that the driver is at least 20 [m] away from the vehicle ahead in the traveling lane of his own vehicle. In addition, since the scan angle of the scanning laser radar 6 is generally about ± 10 °, in detecting a vehicle in an adjacent lane, the scanning direction of the scanning laser radar 6 is shifted by about 10 ° from the front, and in that direction. The vehicle is detected, and the distance X is a distance that is not affected by the shadowing of the vehicle.
It is desirable to set it to about 0.3 [m]. In this way, it is possible to detect vehicles in an adjacent lane at a distance of about 20 [m].

In FIG. 10, the width of the traveling lane is 3.5 [m]. As described above, in the present embodiment, the optimum inter-vehicle distance L1 is detected based on the number of interrupted vehicles and the inter-vehicle distance between adjacent lanes (that is, based on the degree of congestion). It is possible to calculate the optimum inter-vehicle distance. Further, since the surroundings of the vehicle can be grasped by the laser radar used for detecting the inter-vehicle distance, the device can be manufactured at high speed and at low cost.

Further, since the input unit capable of finely adjusting the inter-vehicle distance is provided, it is possible to finely adjust the inter-vehicle time according to the preference of each individual.

[Second Embodiment] The device configuration of an inter-vehicle distance control device according to the second embodiment is the same as that of the first embodiment, and therefore description thereof will not be repeated. In the second embodiment, the flowchart of FIG. 11 is executed in the optimum inter-vehicle distance L1 calculation processing (S9) of FIG.

Referring to FIG. 11, in step S501, the navigation system 11 obtains a standard travel time of a section in which the vehicle has traveled. In step S503, the time actually taken for the vehicle to travel in the section (actual travel time) is measured.

The inter-vehicle time is calculated based on the standard travel time obtained in step S505 and the measured actual travel time, and the optimum inter-vehicle distance L1 is calculated based on the inter-vehicle time and the vehicle speed V. Specifically, if the actual travel time is longer than the standard travel time, it indicates that congestion has occurred, and the optimal inter-vehicle distance L1 is shortened. If the actual travel time is equal to the standard travel time or the actual travel time is shorter than the standard travel time, the optimum inter-vehicle distance L1 is increased to indicate that no congestion has occurred. is there.

In this embodiment, the optimum inter-vehicle distance can be set from the information of the navigation system and the actual travel time.

[Third Embodiment] The configuration of an inter-vehicle distance control device according to a third embodiment is the same as that of the first embodiment, and therefore description thereof will not be repeated. In the third embodiment, the optimum inter-vehicle distance L1 calculation processing (S
In 9), the flowchart shown in FIG. 12 is executed.

Referring to FIG. 12, traffic information and travel time information are input from outside by road-to-vehicle communication unit 12 in step S601. In step S603, the inter-vehicle time is calculated based on the traffic congestion information and the travel time information, and the optimum inter-vehicle distance L1 is calculated based on the inter-vehicle time and the vehicle speed V.

More specifically, the optimum inter-vehicle distance L1 is reduced when traffic congestion occurs or when the input travel time is longer than the standard travel time. Conversely,
When there is no congestion, when the input travel time is shorter than the standard, or when the input travel time is equal to the standard one, the optimum inter-vehicle distance L1 is increased.

In the third embodiment, the optimum inter-vehicle distance can be calculated from traffic jam information and travel time obtained by road-vehicle communication. That is, according to a device such as a radar provided in the vehicle, only information about the surroundings of the own vehicle can be obtained. However, in the present embodiment, a vehicle using information of a wide area by using road-to-vehicle communication is used. Control becomes possible.

It should be noted that in the first to third embodiments described above,
The optimal inter-vehicle distance L1 may be calculated by combining one or three. This way,
The reliability of the optimum inter-vehicle distance L1 can be improved.

In the above-described embodiment, the description has been given of the technique for controlling the inter-vehicle distance when the vehicle is following the preceding vehicle. However, for example, the optimum inter-vehicle distance L1 is calculated as described above, and the forward inter-vehicle distance is calculated during normal traveling of the vehicle. The present invention can also be implemented in a system that calculates the distance to the vehicle and issues a warning when the distance becomes less than or equal to the optimum inter-vehicle distance L1.

It should be noted that the embodiment disclosed this time is an example in all respects and is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an inter-vehicle distance control device using an inter-vehicle distance determination device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of the inter-vehicle distance control device.

FIG. 3 is a block diagram illustrating a configuration of a scanning laser radar.

FIG. 4 is a diagram showing an appearance of the input unit 10;

FIG. 5 is a flowchart for explaining the operation of the control unit 2.

FIG. 6 is a flowchart showing the content of an inter-vehicle distance setting process (S7) based on the switch operation of FIG. 5;

FIG. 7 is a flowchart showing the content of an optimum inter-vehicle distance L1 calculation process (S9) in FIG. 5;

FIG. 8 is a flowchart showing the contents of an interrupt vehicle counting process (S201) of FIG. 7;

9 is a process for calculating an inter-vehicle distance between adjacent lanes in FIG. 7 (S20);
It is a flowchart which shows the content of 3).

FIG. 10 is a diagram for explaining a detection position of a vehicle in an adjacent lane.

FIG. 11 is an optimum inter-vehicle distance L1 according to the second embodiment;
It is a flowchart which shows the content of arithmetic processing.

FIG. 12 is an optimum inter-vehicle distance L1 according to the third embodiment;
It is a flowchart which shows the content of arithmetic processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wheel speed sensor 2 Control unit 6 Scan type laser radar 7 Throttle actuator 8 Warning device 10 Input unit 11 Navigation system 12 Road-to-vehicle communication unit 13 Brake control unit 53 Inter-vehicle time decrease switch 55 Inter-vehicle time increase switch 57 Preceding vehicle follow-up mode setting switch

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3D044 AA00 AB01 AC26 AC55 AC59 AD04 AD21 3G093 AA01 BA23 CB11 DB05 DB16 DB18 EA09 EB04 5H180 AA01 CC03 CC14 DD04 LL01 LL04 LL06 LL09 5J070 AC02 AE01 AF03 AK22 BF12

Claims (7)

[Claims] 1. A detecting means for detecting that another vehicle has interrupted between the own vehicle and a vehicle running ahead of the own vehicle, and an optimum inter-vehicle distance based on a detection result of the detecting means. Determining means for determining the distance between vehicles. 2. The inter-vehicle distance determining apparatus according to claim 1, wherein said detecting means performs detection using a radar. 3. A measuring means for measuring an inter-vehicle distance of a vehicle in a lane adjacent to a lane in which the own vehicle travels, and an optimum inter-vehicle distance of the own vehicle is determined based on the measured inter-vehicle distance. An inter-vehicle distance determining apparatus, comprising: determining means. 4. The inter-vehicle distance determining apparatus according to claim 3, wherein the measuring means performs the measurement using a radar. 5. A storage section for storing a standard travel time of a predetermined section, a measuring section for measuring an actual travel time of the predetermined section, and a storage section for storing the travel time and the measured travel time. Determining means for determining an optimum inter-vehicle distance based on the distance. 6. An inter-vehicle distance determining apparatus, comprising: an obtaining unit that obtains traffic information by communication; and a determining unit that determines an optimal inter-vehicle distance based on the obtained traffic information. 7. The inter-vehicle distance determining apparatus according to claim 1, further comprising an adjusting unit that adjusts the optimum inter-vehicle distance based on an input from a driver.