JP2006142903A - Brake control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid danger that own vehicle is hit by another vehicle accompanying with an automatic brake while avoiding collision of the own vehicle with a front obstacle by suitably operating the automatic brake. <P>SOLUTION: A stop position of the own vehicle when a brake means 3 is operated accompanying with collision precognition by a collision precognition means 11 is determined and it is detected by a dangerous position detection means 14 whether or not there is a dangerous position that it may be easily hit by another vehicle during when it arrives from a position where the brake means 3 is operated at the stop position. Starting of operation of the brake means 3 is delayed when the dangerous position exists. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

    The present invention relates to a vehicle brake control device.

Based on the distance and relative speed between the host vehicle and the obstacle in front, it is determined whether or not the host vehicle may collide with the obstacle. When there is a collision possibility, that is, a collision is predicted. Automatic braking devices that automatically activate the braking means of the host vehicle are sometimes known. For example, Patent Document 1 describes that in such an automatic brake device, the operation start timing of the brake means is changed based on a margin until the host vehicle collides with a front obstacle. Further, in Patent Document 2, the threshold for determining the possibility of collision is changed according to the road conditions on which the host vehicle is traveling. For example, it is determined that the possibility of collision is low at a specific place such as a crossing or an intersection. It is described to prevent the vehicle from stopping (so that it is difficult to apply automatic braking).
Japanese Patent Laid-Open No. 2004-210148 JP-A-5-24524

    However, even if there are places that are inappropriate for stopping, such as at the above-mentioned railroad crossings and intersections, changing the threshold for judging the possibility of collision so that it is difficult to apply automatic braking will prevent the vehicle from stopping at that place. Even if it can be prevented, since the brake is not applied to the host vehicle, the possibility of collision between the host vehicle and the front obstacle at that location is increased.

    Therefore, the present invention appropriately operates the automatic brake to avoid collision between the host vehicle and the front obstacle, and the host vehicle is moved to another vehicle (in addition to automobiles, trams, other railways) along with the automatic brake. It is an object to avoid the danger of collision from a vehicle (including a vehicle).

    In response to such a problem, the present invention determines whether or not the vehicle actually decelerates or stops at a dangerous place such as an intersection when automatic braking is applied, and operates the brake means. The timing was controlled.

That is, the invention according to claim 1 is an obstacle detection means for detecting an obstacle ahead of the host vehicle;
A collision prediction means for determining whether or not the own vehicle may collide with the obstacle detected by the obstacle detection means;
A brake control device for a vehicle, comprising: brake control means for operating the brake means of the host vehicle when a collision is predicted by the collision prediction means;
Calculating means for obtaining a stop position of the host vehicle when the brake means is operated in accordance with the prediction of the collision;
Between the point where the brake means is operated in accordance with the collision prediction and the stop position obtained by the stop position calculating means, there is a dangerous place where the host vehicle is likely to be collided with other vehicles when the host vehicle decelerates or stops. Detecting means for detecting whether or not,
Brake start timing changing means for delaying the operation start timing of the brake means by the brake control means when the detection means detects the presence of a dangerous place.

    Therefore, since the stop point when the brake is operated is obtained in advance and the existence of the dangerous point is determined within a limited range from the point where the brake is applied to the stop point, The brake timing is not changed only by the presence of the brake, that is, the brake timing is not unnecessarily delayed, which is advantageous in avoiding a collision between the host vehicle and an obstacle ahead of the host vehicle. On the other hand, when the host vehicle decelerates or stops at the above dangerous location when the brake means is operated, it is accurately detected. Therefore, the brake start timing is delayed so that the deceleration or stop at the dangerous location is not performed. It is possible to prevent the host vehicle from colliding with other vehicles.

The invention according to claim 2 is the invention according to claim 1,
The detection means further detects a risk level of the dangerous place,
The brake control means delays the start of the operation of the brake means as the danger level of the dangerous part increases.

    That is, when the brake means is operated, the possibility that the own vehicle will collide with another vehicle depends on how difficult it is for the other vehicle to find the own vehicle or the vehicle speed of the other vehicle at the time when the own vehicle is found. Or whether the other vehicle has a road form in which it is difficult to avoid a collision with the host vehicle (for example, whether the road is narrow or a tunnel). In other words, even if it is a dangerous place, the degree of danger of being collided with another vehicle is different.

    Therefore, the risk level of the dangerous part is obtained, and the start of the operation of the brake means is delayed as the risk level increases. Therefore, it is possible to prevent the own vehicle from decelerating or stopping at such a dangerous place with a higher probability, and the possibility of collision from another vehicle is reduced. In addition, the later the operation start timing of the brake means is delayed, the higher the accuracy of determining the possibility that the host vehicle will collide with the front obstacle (the host vehicle may collide with the front obstacle while the operation start timing is delayed. This is advantageous in avoiding unnecessary brake control.

The invention according to claim 3 is the invention according to claim 1 or claim 2,
The detection means performs the detection based on map information of vehicle-mounted navigation means for guiding the host vehicle to a travel destination.

    That is, it is dangerous if the host vehicle suddenly decelerates or stops at the intersection of roads, road corners, or tunnels, and whether the risk of such a dangerous point is high is determined by the road curvature, road Depending on the gradient and the visibility distance of the traveling path in relation to the structure around the road, that is, whether or not the other vehicle can easily find the vehicle, and further depending on the difference between the highway and the urban road, that is, other It depends on the vehicle speed. Thus, such road characteristics and topographical conditions related to the road can be grasped by a map. In view of this, the present invention is configured to detect the dangerous point and further detect the risk based on the map information of the navigation means for guiding the host vehicle to the travel destination.

The invention according to claim 4 is the invention according to claim 1 or claim 2,
The detection means performs the detection based on road traffic information acquired by road-to-vehicle communication.

    That is, the current location information of the host vehicle, static information about the road such as the above-described road characteristics and topographical information related to the road, and dynamic information such as the vehicle speed of other vehicles can be acquired by road-to-vehicle communication. Therefore, in the present invention, detection of the above-mentioned dangerous place and further detection of the degree of danger are performed based on such road traffic information provided from the outside.

    As described above, according to the present invention, the stop position of the host vehicle when the brake means is operated in accordance with the collision prediction is obtained, and a collision occurs from another vehicle between the point where the brake means is operated and the stop position. Since the start of the operation of the brake means is delayed when there is a dangerous place that is likely to be detected, it is possible to accurately detect whether or not the host vehicle will decelerate or stop at the dangerous place. It is advantageous for avoiding deceleration or stopping at a location to prevent a collision from another vehicle, and because the presence of a dangerous location is judged within a limited range, the brake timing is unnecessarily delayed. This is advantageous in avoiding the collision of the host vehicle with the obstacle predicted to be collided.

    Further, according to the risk level of the dangerous part obtained and the start of the operation of the brake means being delayed as the risk level becomes higher, the own vehicle is more likely to decelerate or stop at the high risk level. It can be prevented with a high probability, and the possibility of collision from other vehicles decreases, and the slower the operation start timing of the brake means, the higher the accuracy of determining the possibility that the host vehicle will collide with an obstacle ahead. Therefore, it is advantageous in avoiding useless brake control.

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Overall configuration>
In the brake control device for the vehicle 1 shown in FIG. 1, 2 is a vehicle ahead of the host vehicle, obstacle detection means for detecting other obstacles, 3 is brake means for operating the brakes of each wheel of the vehicle 1, and 4 is obstacles. A controller using a microcomputer that operates the brake means 3 when the vehicle 1 may collide with an obstacle detected by the object detection means 2, that is, when a collision is predicted; A signal from the operation detection unit 10 that detects the operation of the brake unit 3 is input to the controller 4. Further, a three-point seat belt 6 is provided on the seat 5 on which an occupant is seated. The retractor 7 winds up the seat belt 6 with an electric motor at the time of the collision prediction, while the collision detection means 8 uses the vehicle for obstacles. A pretensioner mechanism 9 is provided that explodes explosives and irreversibly winds up the seat belt 6 when a collision is detected. The operation of the pretensioner mechanism 9 is controlled by the controller 4.

    As shown in FIG. 2, the controller 4 includes a collision prediction unit 11 that determines the possibility of collision of the host vehicle 1 against an obstacle detected by the obstacle detection unit 2, and the brake unit 3 based on the collision prediction. And a brake control means 12 for controlling the operation of the vehicle, and in order to change the operation start timing of the brake means 3 by the brake control means 12, the stop position of the host vehicle when the brake means 3 is operated is obtained. A stop position calculation means 13, a dangerous point detection means 14, and a brake start timing change means 15 are provided.

    The collision prediction means 11 calculates the relative speed and relative acceleration between the host vehicle and the obstacle ahead of the host vehicle based on the output of the obstacle detection unit 2, and obtains the safe inter-vehicle distance of the host vehicle. A collision is predicted when the distance to the obstacle is less than the safe inter-vehicle distance. That is, the obstacle detection means 2 is constituted by a millimeter wave radar, and the distance between the own vehicle and the obstacle is obtained by the time until the radar wave emitted from the own vehicle is reflected by the obstacle and returns. It is done. Further, the relative speed and the relative acceleration are obtained based on the time change of the distance, and a preset safe inter-vehicle distance corresponding to the relative speed and the relative acceleration is given.

    Thus, when the collision is predicted by the collision prediction means 11, the brake control means 12 controls the brake means 3 based on the vehicle speed of the host vehicle, the relative speed, the relative acceleration, the inter-vehicle distance, and the like. (Brake start timing Ts and brake strength (target deceleration G)) are set.

The stop position calculating means 13 calculates the braking time Te until the brake is finished when the brake means 3 is operated at the timing Ts from the current vehicle speed V of the host vehicle and the deceleration G due to the operation of the brake means 3. When the vehicle speed Ve = 0 at the end of braking and the deceleration G = 0.5 × 9.8 m / s ² ,
Ve = V−G × Te
0 = V−0.5 × 9.8 × Te
Te = V / (0.5 × 9.8) [sec]
It becomes.

And the stop position calculation means 13 calculates | requires the moving distance S of the own vehicle in the said brake time Te,
S = V × Te−1 / 2 × G × Te ²
The brake end point moved S [m] from the brake start point at which the brake means 3 is operated at the timing Ts is calculated from the map information of the navigation means described later.

    Based on the data acquired from the road traffic data supply means 16, the dangerous point detection means 14 is likely to collide with other vehicles when the host vehicle 1 decelerates or stops in the brake section from the brake start point to the brake end point. Whether or not there is a dangerous spot and the degree of danger are detected.

    The data supply means 16 obtains the information from the navigation means provided in the own vehicle 1 for guiding the own vehicle 1 to the travel destination, and the beacon receiving antenna from the communication network providing road traffic information such as VICS. And an information receiver.

   That is, the navigation means receives a transmission radio wave from a GPS artificial satellite, and based on this, detects a change in the traveling direction of the host vehicle and a GPS antenna / receiver for calculating the current location and traveling direction of the host vehicle. A gyro compass for the vehicle, a vehicle speed sensor for the own vehicle, an input means for the occupant to input various commands such as input of the travel destination of the host vehicle, designation of a travel route from the current location to the destination, and map information A player for reading out the map information from a stored storage medium (DVD or CD-ROM), a display for displaying a road map and the current location, and information from each of these means are incorporated to mainly store the vehicle. Navigation control to display the current location, direction of travel, destination, travel route, etc. on the display to guide the driver of the vehicle to the driver And a knit.

    In the storage medium, as map information, road maps, railway maps, river water map, etc., road width, lane width, road type (highway, suburban roads and urban roads), one-way Other road attributes, the altitude of each point on the road, the position of the traffic light, etc. are stored.

    The road traffic information receiver obtains the current location information, branch point information, road guidance information, accident information, traffic jam information, and other dynamic information about the flow of vehicles from the communication network that provides the road traffic information. To do.

    In the case of this embodiment, the map information of the navigation means and the information on the road and traffic obtained by the road traffic information receiver are used as data for the detection by the dangerous point detection means 14.

    The dangerous point detection means 14 detects the presence of a dangerous point in the brake section and the degree of danger from the following viewpoints 1-4. That is, based on a plurality of pieces of information related to the risk of being easily collided with other vehicles in the brake section, the risk level is evaluated as a risk location.

  1. Is there a place in the brake section where the other vehicle discovers the vehicle (the driver of the other vehicle discovers, the same applies hereinafter) that is likely to be delayed. As this timing is delayed, the driving operation for avoiding the collision of the other vehicle with the host vehicle is delayed, and the risk of collision increases.

    Specifically, information A regarding the road gradient (the stronger the uphill, the more difficult it is to see from the uphill position where the road has moved from the uphill to the flat road or downhill, so the timing of the discovery is delayed and the risk is high) , Information B regarding road curvature (the greater the road curvature, the more difficult it is to find a vehicle in which the curved portion and the portion following the curved portion cannot be seen in front of the curved portion, so the timing of the discovery is delayed and the risk is high) In addition, information C regarding the road visibility distance in relation to roadside trees, buildings, etc. is obtained from the map information of the navigation means (the shorter the visibility distance C, the later the timing of the above discovery and the higher the risk). The information is evaluated numerically (for example, 10-level evaluation).

  2. Is there a place in the brake section where the vehicle speed of the other vehicle is predicted to be high when the other vehicle is found by the other vehicle? The higher the vehicle speed of the other vehicle, the higher the degree of danger because it is likely to collide with the host vehicle even if the avoidance driving operation is performed.

    Specifically, information D regarding the flow of the vehicle obtained by the road traffic information receiver (has a higher degree of danger as the flow of the vehicle becomes higher), information E regarding the type of road obtained from the map information (other vehicles on highways) The vehicle speed is high and the danger level is high), and the road width information F (the wider the road width, the higher the vehicle speed of other vehicles and the higher the danger level) is evaluated numerically.

  3. Is there a location in the brake section where other vehicles cannot avoid a collision? The longer the distance that cannot be avoided, the higher the risk.

    Specifically, information G regarding the distance at which the brake section and the tunnel without a retreat road overlap (the longer the overlap distance, the more the other vehicle cannot avoid the collision and the higher the risk), and the right turn intersection overlaps Information H about distance (the longer the overlapping distance is, the more vehicles cannot avoid collision and the higher the risk) is obtained from the map information, and the information is evaluated numerically (for example, 10-step evaluation).

  4). Is there a location where an accident occurred before in the above brake section? The risk increases as the number of accidents at the location increases.

    Specifically, when the road traffic information provider provides past accident information, the accident information I obtained by the road traffic information receiver (the accident history at each point is stored in the storage medium of the vehicle-mounted navigation means). If it is stored, the accident information) is evaluated numerically.

Next, the dangerous part detection means 14 gives a coefficient (weighting) according to the influence on the risk of each piece of information to the evaluation values of the information A to I, and obtains the evaluation level Z of the risk degree. That is,
Z = A × a + B × b + C × c +... + I × i
In this case, uppercase letters such as A, B, and C are evaluation values, and lowercase letters such as a, b, and c are corresponding coefficients. The dangerous point detection means 14 sets a case where the evaluation level Z is equal to or higher than a predetermined value as a dangerous point where the brake start timing described later is to be delayed.

    Then, the brake start timing changing means 15 delays the operation start timing Ts of the brake means 3 by the brake control means 12 when the dangerous place detecting means 14 detects that a dangerous place exists in the brake section. In that case, the brake start timing changing means 15 increases the delay of the operation start timing Ts as the risk evaluation level Z is higher.

    In the case of the present embodiment, the dangerous point detection means 14 is based on the evaluation level Z, the risk level is small (Z <first predetermined value), the risk level is medium (first predetermined value ≦ Z <second predetermined value), and the risk level. The degree of danger is judged in three stages of large (Z ≧ second predetermined value), and the places where the degree of danger is high and where the degree of danger is high are designated as dangerous places where the brake start timing should be delayed. The brake start timing changing means 15 increases the delay of the operation start timing Ts when the risk is greater than when the risk is medium.

    FIG. 3 shows a flow of brake start timing change control by the controller 4. In step S1 after the start, the possibility of collision by the collision predicting means 11 is determined. When it is determined that there is a possibility of collision, the process proceeds to step S2, and the brake control condition is set by the brake control means 12.

    In the next step S3, it is detected by the dangerous part detecting means 14 whether or not there is a dangerous part in the brake section obtained by the stop position calculating means 13, and if there is a dangerous part, the process proceeds to step S4 and the degree of danger is determined. It is determined whether or not it is small. When there is no dangerous part or when the degree of danger is small, the process proceeds to step S5, and the brake control is executed without changing the brake control condition.

    When it is determined in step S4 that the degree of risk is not low, the process proceeds to step S6, and it is determined whether or not the degree of risk is medium. When it is determined that the degree of risk is medium, the process proceeds to step S7, where the brake operation start timing is delayed by the control period X times of the brake control by the brake start timing changing means 15, and the brake control is executed. When it is determined in step S6 that the degree of danger is not in danger (when the degree of danger is high), the process proceeds to step S8, and the brake operation start timing is delayed by the control cycle Y times by the brake start timing changing means 15 to execute the brake control. Is done. In this case, X <Y.

    Therefore, the brake control of the present invention will be described based on a specific example. As shown in FIG. 4, for example, when the host vehicle 1 approaches a road curve, a front obstacle (in this case, a forward traveling vehicle) 21 It may be predicted that there is a possibility of collision. In this case, when the brake means 3 is operated as scheduled, the host vehicle 1 is slowed down or stopped at a spot (position of the host vehicle 1 shown in the figure) that becomes a blind spot when viewed from the other vehicle 22 that follows. The timing at which the other vehicle 22 discovers the host vehicle 1 is delayed, and the possibility of a collision from the other vehicle 22 increases.

    On the other hand, according to the present invention, the brake section L when the brake means is actuated as planned is obtained, and when there is the blind spot in the brake section L, it is determined that there is a dangerous place, and the brake means 3 The timing to activate is delayed.

    Accordingly, the host vehicle 1 is braked in a state where it is closer to the front traveling vehicle 21 that is an obstacle. However, the vehicle 1 is largely decelerated by the brake, or is in a stopped state before the brake is applied. By the time, the own vehicle 1 moves away from the blind spot. For this reason, possibility that the own vehicle 1 will collide with the other vehicle 22 which follows is reduced.

    Further, since the start of the brake operation is delayed as described above, during this delay or while the vehicle is decelerating with the brake operation, the inter-vehicle distance between the host vehicle 1 and the forward traveling vehicle 21 increases, The possibility of collision with the traveling vehicle 21 is expected to be eliminated. In this case, the brake means 3 need not be operated, or the brake can be released early even if the brake means is operated.

    In the above embodiment, in addition to static information such as road characteristics, road-related topographical conditions, and past accident histories, vehicle speed information of other vehicles obtained from VICS, brake sections, and tunnels and right-turn intersections overlap. The dynamic information obtained during travel of the vehicle, such as the distance, was used to determine the dangerous location and its risk level. Based on the static information, the road risk location and the risk level are determined in advance and recorded on the recording medium. In addition, based on the information recorded on the recording medium, it may be determined whether or not there is a dangerous point in the brake section, and further, the degree of danger may be obtained. You may make it correct | amend based on.

It is a block diagram which shows the brake control apparatus of a vehicle. It is a control block diagram of the control device. It is a control flowchart of the same control apparatus. It is explanatory drawing which shows the example of a delay of brake operation start timing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Own vehicle 2 Obstacle detection means 3 Brake means 4 Controller 11 Collision prediction means 12 Brake control means 13 Stop position calculation means 14 Hazardous location detection means 15 Brake start timing change means 21 Obstacle 22 Other vehicles

Claims (4)

Obstacle detection means for detecting an obstacle ahead of the host vehicle;
A collision prediction means for determining whether or not the own vehicle may collide with the obstacle detected by the obstacle detection means;
A brake control device for a vehicle, comprising: brake control means for operating the brake means of the host vehicle when a collision is predicted by the collision prediction means;
Calculating means for obtaining a stop position of the host vehicle when the brake means is operated in accordance with the prediction of the collision;
Between the point where the brake means is operated in accordance with the collision prediction and the stop position obtained by the stop position calculating means, there is a danger point where the host vehicle is likely to collide with another vehicle when the host vehicle decelerates or stops. Detecting means for detecting whether or not,
A brake control device for a vehicle, comprising: a brake start timing changing means for delaying an operation start timing of the brake means by the brake control means when the detection means detects the presence of a dangerous place. In claim 1,
The detection means further detects a risk level of the dangerous place,
The brake control device for a vehicle according to claim 1, wherein the brake control means delays the start of operation of the brake means as the degree of danger of the dangerous part increases. In claim 1 or claim 2,
The vehicle brake control device according to claim 1, wherein the detection means performs the detection based on map information of an in-vehicle navigation means for guiding the host vehicle to a travel destination. In claim 1 or claim 2,
The vehicle brake control apparatus, wherein the detection means performs the detection based on road traffic information acquired by road-to-vehicle communication.

Images