JP2008162456A - Automatic braking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost automatic braking device capable of increasing the possibility of avoiding a collision between one's own vehicle and an obstacle even when a driver neglects manipulated input. <P>SOLUTION: This automatic braking device includes: collision possibility determining means for determining the possibility of the collision of the own vehicle with the obstacle; manipulated input detecting means 4 for detecting the manipulated input by the driver; positional relationship detecting means 2 for detecting the lateral positional relationship between the obstacle and the own vehicle; an avoidable direction determining means for determining the avoidable direction of the own vehicle based on the detected result by the positional relationship detecting means 2; and braking force control means for automatically operating a brake 20 by generating differences among the braking forces of respective wheels so as to enhance the turning property for direction change of the own vehicle in the avoidable direction when the possibility of coming into collision with the obstacle is determined by the collision possibility determining means and the manipulated input by the driver is not detected by the manipulated input detecting means 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an automatic braking device that automatically operates a brake.

  As a conventional technique, for example, as disclosed in Patent Document 1, a driver's steering operation is detected, and the brake pressure is controlled for each wheel so that the turning ability of the vehicle in the operation direction is improved. 2. Description of the Related Art There is known an automatic brake control device configured to improve the turning performance of a vehicle with respect to a steering operation for avoiding a collision while maintaining the braking performance of the vehicle.

  Further, as disclosed in Patent Document 2, an automatic steering device is provided in addition to an automatic braking device that avoids a collision with an obstacle, and the automatic steering device is activated when a collision possibility with an obstacle occurs. There has been known a vehicle contact prevention device configured to change the traveling direction of the host vehicle and to increase the possibility of avoiding a collision with an obstacle.

Japanese Patent Laid-Open No. 7-21500 (see FIG. 6 and paragraph number “0009”) Japanese Patent Laid-Open No. 5-58319 (see FIG. 7 and paragraph number “0030”)

  The automatic brake control device of Patent Literature 1 is configured to control the brake pressure for each wheel so that the turning performance of the vehicle in the steering operation direction is enhanced when the steering is operated by the driver. Yes. For this reason, when the driver neglects the steering operation by looking aside or falling asleep, it is impossible to avoid a collision between the vehicle and the obstacle by controlling the brake pressure for each wheel.

Further, in the vehicle contact prevention device disclosed in Patent Document 2, even if the driver does a side-by-side driving or dozes and neglects the steering operation, the automatic steering device is operated to activate the self-vehicle and the obstacle. The possibility of avoiding the collision of the automatic steering cylinder (56 in Patent Document 2 in FIG. 7), the switching valve (60 in Patent Document 2 in FIG. 7), and the automatic steering valve (Patent Document 2 in FIG. 7) is improved. 7) 61) etc. are required to construct an automatic steering device, and the automatic steering device is expensive and can increase the possibility of avoiding a collision between the host vehicle and an obstacle. There is a problem that the manufacturing cost increases.
An object of the present invention is to realize an automatic braking device that can increase the possibility of avoiding a collision between an own vehicle and an obstacle even when a driver neglects an operation input at low cost.

[I]
(Constitution)
The first feature of the present invention is that the automatic braking device is configured as follows.
Collision possibility judging means for judging the possibility of collision of the own vehicle with an obstacle, operation input detecting means for detecting an operation input of the driver, and a position for detecting the positional relationship between the obstacle and the own vehicle in the left-right direction It is determined that there is a possibility of colliding with an obstacle by a relationship detection unit, an avoidable direction determination unit that determines an avoidable direction of the host vehicle based on a detection result of the positional relationship detection unit, and the collision possibility determination unit When the operation input of the driver is not detected by the operation input detection means, the brake force of each wheel is caused to be different so that the turning ability of the vehicle in the avoidable direction is increased. A brake force control means for automatically operating the automatic braking device.

(Function)
According to the first feature of the present invention, when it is determined that there is a possibility of colliding with an obstacle, even if the driver does not input an operation, the vehicle is moved in an avoidable direction by the brake force control means. The possibility of avoiding a collision of the own vehicle with an obstacle can be increased. As a result, for example, even if the driver makes a side-by-side driving or sleeps and neglects an operation input, the possibility of automatically avoiding a collision of the host vehicle with an obstacle can be increased. In addition, it is possible not only to increase the possibility of avoiding a collision with an obstacle of the own vehicle, but also to urge the driver to avoid the vehicle by steering, and assist the driver in avoiding the vehicle in the avoidance direction by the driver's steering. it can.

  According to the first feature of the present invention, it is possible to increase the possibility of avoiding a collision of the host vehicle with an obstacle with a relatively simple structure by causing a difference in the braking force by the braking force control means. As a result, the possibility of avoiding the collision between the host vehicle and the obstacle is increased as compared with a case where the possibility of avoiding the collision between the host vehicle and the obstacle can be increased by, for example, an automatic steering device. It is possible to simplify the structure of the automatic braking device that can be used.

(The invention's effect)
According to the first feature of the present invention, an automatic braking device that can increase the possibility of avoiding a collision between the host vehicle and an obstacle even when the driver neglects an operation input can be realized at low cost.

[II]
(Constitution)
The second feature of the present invention resides in the following configuration in the automatic braking device of the first feature of the present invention.
A vehicle stabilization control device for controlling the attitude of the vehicle by controlling the braking force based on the detection result of the operation input detection means;
The brake force control means is configured so that the vehicle stabilization control device operates in preference to the brake force control means.

(Function)
According to the second feature of the present invention, the “action” described in the preceding item [I] is provided in the same manner as the first feature of the present invention, and in addition to this, the following “action” is provided.
According to the second feature of the present invention, it is possible to prevent the braking force control means and the vehicle stabilization control apparatus from operating redundantly, and when the situation is such that the braking force control means and the vehicle stabilization control apparatus are operating redundantly (for example, the braking force control means is Vehicle stabilization when the vehicle stabilization control device is activated under conditions of operation or when the brake force control means is activated with the vehicle stabilization control device activated. By giving priority to the operation of the control device, it is possible to prevent the vehicle from becoming unstable by operating the braking force control means and improving the turning ability, and the vehicle stabilization control device can stabilize the posture of the vehicle. it can.

(The invention's effect)
According to the second feature of the present invention, the “effect of the invention” described in the preceding item [I] is provided in the same manner as the first feature of the present invention. In addition, the following “effect of the invention” is provided. ing.
According to the 2nd characteristic of this invention, the fall of the performance of a vehicle stabilization control apparatus can be prevented.

[III]
(Constitution)
The third feature of the present invention resides in the following configuration in the automatic braking device of the first feature or the second feature of the present invention.
Brake avoidance distance calculating means for calculating a braking avoidance distance to an obstacle capable of avoiding a collision with an obstacle of the own vehicle by braking, and steering to an obstacle capable of avoiding a collision of the own vehicle with the obstacle by steering Steering avoidance distance calculating means for calculating an avoidance distance; and automatic brake operating means for automatically operating a brake when the actual distance between the host vehicle and the obstacle is shorter than the steering avoidance distance and shorter than the braking avoidance distance; Prepared,
When the actual distance between the host vehicle and the obstacle becomes shorter than the steering avoidance distance at the relative speed between the host vehicle and the obstacle at which the braking avoidance distance is shorter than the steering avoidance distance, the brake force control unit is not activated. The brake force control means is configured.

(Function)
According to the third feature of the present invention, the “action” described in the preceding item [I] [II] is provided in the same manner as the first feature or the second feature of the present invention. Is provided.
According to the third aspect of the present invention, the brake force control means is operated at a relative speed in which the avoidance by the steering of the collision of the own vehicle to the obstacle is superior to the avoidance by the braking of the collision of the own vehicle to the obstacle. The possibility of avoiding a collision between the host vehicle and the obstacle can be further increased.

(The invention's effect)
According to the third feature of the present invention, the “effect of the invention” described in the preceding paragraphs [I] and [II] is provided in the same manner as the first feature or the second feature of the present invention. “Effect of the invention” is provided.
According to the third aspect of the present invention, the brake force control means can be operated at an appropriate time.

[IV]
(Constitution)
A fourth feature of the present invention resides in the following configuration in the automatic braking device of the third feature of the present invention.
When the operation input of the driver is detected by the operation input detection means in a state where the brake is automatically operated by the automatic brake operation means, so as to cancel the automatic operation of the brake by the automatic brake operation means, The automatic brake actuating means is configured.

(Function)
According to the fourth feature of the present invention, the “action” described in the previous section [III] is provided in the same manner as the third feature of the present invention. In addition, the following “action” is provided.
According to the fourth aspect of the present invention, the driver's operation input is respected, and the automatic operation of the brake by the automatic brake operation means can be released, preventing the brake from automatically operating against the driver's intention. it can.

(The invention's effect)
According to the fourth feature of the present invention, the “effect of the invention” described in the previous section [III] is provided in the same manner as the third feature of the present invention. In addition, the following “effect of the invention” is provided. ing.
According to the fourth feature of the present invention, it is possible to increase the possibility of avoiding a collision between the host vehicle and an obstacle while maintaining a good driving feeling while respecting the driver's driving intention.

[Configuration of vehicle control device]
FIG. 1 shows a block diagram of a vehicle equipped with an automatic braking device according to the present invention. As shown in FIG. 1, detection devices such as a camera 1, a radar 2, a yaw rate sensor 3, a steering angle sensor 4, a vehicle speed sensor 5, a lateral acceleration sensor 6, and a pressure sensor 7 are mounted on the vehicle. Are connected to the ECU 8.

  The camera 1 is disposed, for example, on a stay (not shown) of a rearview mirror in a vehicle interior, and is configured to be able to photograph the front of the vehicle. The video imaged by the camera 1 is processed by an image processing device (not shown) so that the ECU 8 can detect an obstacle ahead of the vehicle, a white line defining a travel lane in which the vehicle travels, a guardrail, and the like. Yes.

  The radar 2 is juxtaposed side by side at a plurality of locations in the front of the vehicle. The radar 2 projects laser light in front of the vehicle and receives the laser light reflected by an obstacle such as a preceding vehicle. The actual distance between the vehicle and the obstacle (hereinafter referred to as an inter-vehicle distance L), the position of the obstacle in the left-right direction, and the relative speed of the vehicle with respect to the obstacle are detected.

  The yaw rate sensor 3 is disposed near the position of the center of gravity of the vehicle and detects the yaw rate acting on the vehicle. The steering angle sensor 4 is assembled to a steering shaft (not shown) of the steering handle, calculates the steering angle of the left and right front wheels by measuring the rotation angle of the steering shaft from the reference position, and the driver's An operation amount (steering operation amount) of the steering handle and an operation speed (steering operation speed) of the steering handle are detected.

  The vehicle speed sensor 5 and the lateral acceleration sensor 6 are assembled in the vehicle, and detect the vehicle speed and the acceleration acting in the lateral direction of the vehicle, respectively.

  A display unit 9, an alarm device 10, a brake control unit 11, and a stop lamp are connected to the ECU 8. The display unit 9 and the alarm device 10 are installed in the passenger compartment, and provide visual and audible information to the driver based on the output from the ECU 8.

  The brake control unit 11 supplies electric power to a switching valve 27, a pressure increasing valve 28, and a pressure reducing valve 29 that constitute a brake device 13 for each wheel, which will be described later, based on the output from the ECU 8, and the detected pressure from the pressure sensor 7 is supplied. The brake 20 of each wheel is increased / decreased while feeding back, and the brake 20 is operated to each wheel. When the brake 20 is actuated by the brake control unit 11, a stop lamp 12 provided at the rear of the vehicle is turned on.

  Each of the detection devices described above is connected to the ECU 8, and based on the detection result from each of the detection devices, an output from the ECU 8 to the alarm device 10, the brake control unit 11 and the like is performed, so that an automatic brake actuating means described later and Brake force control means can be realized.

[Configuration of brake device]
The brake device 13 equipped on this vehicle will be described with reference to FIG. As shown in FIG. 2, the brake device 13 includes a master cylinder 21, a hydraulic pump 24, an accumulator 26, an oil tank 25, a switching valve 27, a pressure increasing valve 28, a pressure reducing valve 29, and the like. The master cylinder 21 is linked to the brake pedal 23 via a master back 22 and generates a brake pressure corresponding to the depression force of the brake pedal 23 by the master back 22 being increased.

  The hydraulic pump 24 is configured as a motor drive type, and is connected to the pressure increasing valve 28. An oil tank 25 and an accumulator 26 are connected to the suction side and the discharge side of the hydraulic pump 24, respectively, and the pressure oil sucked from the oil tank 25 and pressurized is stored in the accumulator 26 and can be held at a constant pressure. Has been.

  The switching valve 27 is connected to an oil passage that communicates with the master cylinder 21 and each brake 20. When the switching valve 27 is operated to the open position, a brake pressure corresponding to the depression force of the brake pedal 23 can be generated. When the switching valve 27 is operated to the closed position, the brake pressure can be increased or decreased electrically in accordance with the operation of the pressure increasing valve 28 and the pressure reducing valve 29 described above.

  The pressure increasing valve 28 is connected to an oil passage that communicates the hydraulic pump 24 and each brake 20. By switching the pressure increasing valve 28, the pressure oil from the accumulator 21 is supplied to the brake 20 to electrically The brake pressure of the brake 13 can be increased.

  The pressure reducing valve 29 is connected to an oil passage that is bypassed from an oil passage that communicates the brake 20 and the pressure increasing valve 28. By switching the pressure reducing valve 29, a part of the pressure oil from the brake 20 is transferred to the oil tank 25. The brake pressure can be reduced electrically.

  A check valve is connected so as to bypass the switching valve 27, and the brake pressure can be increased by depressing the brake pedal 23 even when the switching valve 27 is operated to the closed position. Yes.

  A pressure sensor 7 is connected to an oil passage that communicates the master cylinder 21 and each brake 20, and the brake pressure of each wheel measured by this pressure sensor 7 is fed back, and each wheel is controlled by a brake force control means described later. A differential pressure can be generated in the brake pressure.

  As shown in FIG. 1, the switching valve 27, the pressure increasing valve 28, and the pressure reducing valve 29 that constitute the brake device 13 are connected to the brake control unit 11, and each brake 20 is connected to the brake 20 based on the output from the ECU 8. Different brake pressures can be applied.

[Calculation of eccentricity]
Based on FIG. 3, the calculation of the amount of eccentricity by the radar 2 as the positional relationship detecting means will be described. As shown in FIG. 3, the radars 2 are installed at a plurality of locations on the left and right sides of the front portion of the vehicle. The detection results by the respective radars 2 are input to the ECU 8, and the distance between the own vehicle and the obstacle in the traveling direction of the own vehicle at each position is constantly monitored by the plurality of radars 2.

  A specific example of calculating the amount of eccentricity will be described with reference to FIG. For example, as shown in FIG. 3A, when the distance between the host vehicle and the obstacle detected by the radars 2A, 2B, 2C, and 2D is substantially the same distance, the eccentricity between the host vehicle and the obstacle is For example, as shown in FIG. 3B, the distance between the own vehicle detected by the radars 2A and 2B and the obstacle is substantially the same distance, and the own vehicle detected by the radars 2C and 2D When the distance between the host vehicle and the obstacle detected by the radars 2A and 2B is longer than the distance between the host vehicle and the obstacle (or when the distance between the host vehicle and the obstacle is not detected by the radars 2C and 2D), The eccentricity with the obstacle is calculated as 50%. For example, as shown in FIG. 3C, the distance between the own vehicle detected by the radars 2B, 2C, and 2D and the obstacle is detected by the radar 2A. Longer than the distance between the vehicle and the obstacle Or radar 2B, 2C, when the distance between the vehicle and the obstacle is not detected by the 2D) calculates the eccentricity between the vehicle and the obstacle 75%.

  Although FIG. 3 shows an example in which the host vehicle is offset to the right in the traveling direction with respect to the obstacle (preceding vehicle), the eccentricity is similarly caused when the host vehicle is offset to the left in the traveling direction with respect to the obstacle. The amount is calculated, in which case the eccentricity value (%) is a negative value.

  3 shows an example in which the radars 2 are mounted at the four front portions of the vehicle. However, the number of radars 2 may be different (a plurality or one). By increasing, the detection accuracy of the eccentricity can be improved. Further, for example, one radar 2 capable of projecting and receiving a plurality of laser beams in front of the vehicle may be mounted on the front portion of the vehicle so as to detect the positional relationship of the obstacle in the left-right direction. Furthermore, it may be configured to detect the eccentricity between the host vehicle and the obstacle by performing image processing on the video imaged by the camera 1 mounted on the vehicle, or a configuration in which the radar 2 and the camera 1 are used together. By adopting, the detection accuracy of the eccentricity can be further improved.

[Avoidable direction determination means]
Based on the amount of eccentricity between the host vehicle and the obstacle calculated based on the detection value detected by the radar 2 and the information detected by the camera 1, the avoidable direction determination unit determines the avoidable direction of the host vehicle. Specifically, when the eccentric amount of the host vehicle and the obstacle calculated based on the detection result detected by the radar 2 is a positive value, the avoidable direction is determined as the right direction, and the eccentricity is a negative value. In this case, the avoidable direction is determined to be the left direction.

  However, for example, when a guardrail or the like is detected in the left direction of the host vehicle based on information detected by the camera 1, it is determined that left avoidance is impossible and correction is made in the avoidable direction described above, even if the amount of eccentricity is negative. Even if the value is, the avoidable direction is determined to be the right direction. In addition, for example, when an oncoming vehicle or a parallel vehicle is detected in the right direction of the host vehicle based on information detected by the camera 1, it is determined that the right avoidance is impossible and correction is made in the avoidable direction described above, Even if the amount of eccentricity is a positive value, the avoidable direction is determined to be the left direction.

  For example, when the eccentricity is 0% and it is determined that the left and right directions can be avoided based on the information detected by the camera 1, the right direction or the left direction is preferentially determined as the avoidable direction, and the camera In the case where it is determined that avoidance is not possible in both the left and right directions based on the information detected by 1, it is determined that it cannot be avoided in either direction and is determined as avoidable.

[Calculation of brake pressure]
Based on FIG. 4, a method for calculating the brake pressure used when the brake force control means described later is implemented will be described. Based on the amount of eccentricity between the host vehicle and the obstacle calculated based on the detection value detected by the radar 2, the relative speed, the vehicle speed, and the like, the brake pressure when the brake force control means described later is implemented is calculated. Specifically, for example, when the amount of eccentricity between the host vehicle and the obstacle is large and the turning moment that acts on the host vehicle to improve the turning ability of the vehicle is relatively small, the brake pressure is set low. When the amount of eccentricity between the host vehicle and the obstacle is small and the turning moment applied to the host vehicle for improving the turning ability of the vehicle is relatively large, the brake pressure is set high.

  Note that the brake pressure for each wheel that is applied to increase the turning ability of the host vehicle by the brake force control means to be described later is not set only by the amount of eccentricity described above, for example, relative speed with an obstacle, vehicle speed, etc. These factors are determined in a complex manner.

  An example of the brake coefficient for each eccentric amount will be described based on FIG. As shown in FIG. 4, for example, when the amount of eccentricity is + 50% (in the case of FIG. 3B), the left front brake 20FL and the right rear brake 20FL are applied to the brake pressure of the left rear brake 20RL. The brake coefficient is set so that three times the brake pressure is applied, and six times the brake pressure is applied to the right front brake 20FR with respect to the brake pressure of the left rear brake 20RL.

  The brake coefficient is set to increase as the amount of eccentricity decreases. For example, when the amount of eccentricity is positive, the brake pressure of the right front brake 20FR is set so as to increase in proportion to the amount of eccentricity decreasing with respect to the brake pressure of the left rear brake 20RL (3 times → (6 times → 9 times), the greater the amount of eccentricity, the greater the difference between the left rear brake 20RL and the right front brake FR, and the greater the turning moment that increases the turning ability of the vehicle. Has been. The brake coefficient is shown as an example, and different numerical values may be adopted.

  When the switching valve 27, the pressure increasing valve 28, and the pressure reducing valve 29 are operated by outputting from the ECU 8 to the brake control unit 11 by a brake force control means to be described later, the brake pressure of each brake 20 detected by the pressure sensor 7 is fed back. However, by increasing or decreasing the brake pressure of each brake 20 to a predetermined pressure based on the brake coefficient, the brake pressure based on the brake coefficient calculated by the method described above can be applied to the brake 20 of each wheel.

[Vehicle stabilization control measures]
This vehicle is equipped with a known side slip prevention device (hereinafter referred to as VSC) as an example of a vehicle stabilization control device. The details of this VSC will be omitted, but the outline will be described. The steering angle of the driver's steering wheel is calculated based on the detection result of the steering angle sensor 4, and the driver is going to advance from this steering angle. When the vehicle speed is read and the vehicle speed detected by the vehicle speed sensor 5 is too high for the route, control is performed for automatically decelerating even if the driver does not step on the brake pedal 23 so that the vehicle does not deviate from the route. It is a device that performs control such as distributing the left and right brake pressures.

  In other words, when the driver steers while the vehicle is running, the direction of the vehicle changes and the vehicle rolls, and the tire of the turning inner wheel exceeds the grip limit of the road surface and the vehicle starts to slide sideways. Therefore, by detecting and calculating the magnitude and speed of the steering, the speed of the vehicle, the speed of the lateral movement of the vehicle, and the speed of the change in the direction of the vehicle, the time when the wheels slide is predicted to start the side slip. The brake pressure of the wheel is controlled in advance to avoid the side slip of the wheel.

[Relationship between braking avoidance distance and steering avoidance distance]
Based on FIG. 5, the relationship between the braking avoidance distance and the steering avoidance distance used for the automatic brake actuating means and the brake force control means described later will be described. FIG. 5 shows that there is an obstacle in front of the vehicle, the minimum distance to the obstacle that the vehicle can physically avoid by collision with the obstacle (hereinafter referred to as a braking avoidance distance), and the vehicle It is the graph which showed the relationship of the minimum distance (henceforth a steering avoidance distance) to the obstacle which can physically avoid the collision with an obstacle by steering. In FIG. 5, the horizontal axis represents the relative speed between the host vehicle and the obstacle, and the vertical axis represents the distance from the braking start position or the steering start position.

  As shown in FIG. 5, the braking avoidance distance increases approximately in a quadratic curve as the relative speed increases from the vehicle performance, and the steering avoidance distance is relative to the geometrical relationship between the vehicle and the obstacle. It increases substantially linearly with increasing speed. In the region where the relative speed is smaller than the predetermined value, the steering avoidance distance is longer than the braking avoidance distance, and in the region where the relative speed is larger than the predetermined value, the steering avoidance distance is shorter than the braking avoidance distance.

  The graph showing the relationship between the relative speed, the braking avoidance distance, and the steering avoidance distance shown in FIG. 5 shows the relationship when the amount of eccentricity described later is constant. For example, when the amount of eccentricity becomes a small value, FIG. The curves and straight lines shown move upward in FIG. 5 and the braking avoidance distance and steering avoidance distance become longer. Conversely, when the amount of eccentricity becomes a large value, the curves and straight lines shown in FIG. 5 move downward in the plane of FIG. 5 and the braking avoidance distance and the steering avoidance distance become short.

  The collision possibility line (physical avoidance limit line) shown in FIG. 5 is a straight line and a curve used to determine the possibility of collision between the host vehicle and the obstacle in the automatic braking device described later, and is indicated by the oblique lines in FIG. The region indicates a region where the collision cannot be avoided by either the driver's braking or steering, and the braking avoidance distance and the steering avoidance distance curve and straight line positioned at the upper limit of the region indicate the collision limit line. In addition, the curves and straight lines indicated by the dotted line, the one-dot chain line and the two-dot chain line in FIG. 5 and the display of L1 to L4 indicate the warning device 10 when the automatic brake actuating means or the brake force control means described later is implemented. Threshold values used for determination of automatic operation, automatic operation and release of the brake 20, and brake differential pressure operation and release are shown. In the following description, an area where the relative speed where the braking avoidance distance is shorter than the steering avoidance distance is relatively small is referred to as a braking dominant area, and an area where the relative speed where the steering avoidance distance is shorter than the braking avoidance distance is relatively large is steered. This is called the dominant area.

[Automatic braking device]
A flowchart of the automatic braking device will be described with reference to FIGS. FIG. 6 shows a main routine of the automatic braking device, FIG. 7 shows a subroutine of the automatic braking device when shifting to the automatic brake operating means, and FIGS. 8 and 9 are cases when shifting to the braking force control means. The subroutine of an automatic brake device is shown.

  Based on FIG. 6, the main routine of the automatic braking device in the present embodiment will be described. As shown in FIG. 6, data detected by the detection devices shown in FIG. 1 and input to the ECU 8 is constantly monitored (step # 11). Based on the detection result detected by the radar 2, the inter-vehicle distance L and the relative speed between the host vehicle and the obstacle are calculated (step # 12).

  Next, based on the calculated inter-vehicle distance L and the relative speed, it is determined by the collision possibility determination means whether or not the host vehicle may collide with an obstacle (step # 13). The possibility of collision between the host vehicle and the obstacle by the collision possibility determining means is determined based on FIG. 5 described above, and when the inter-vehicle distance L at the calculated relative speed falls below the collision possibility line of FIG. It is determined that the host vehicle may collide with an obstacle.

  If it is determined that the host vehicle may collide with an obstacle (step # 13, Yes), it is determined whether or not the vehicle is in an unstable posture in which the VSC operates (step # 13). 14). If the VSC is not operating (step # 14, No), it is determined whether or not an emergency avoidance operation by the driver has been performed (step # 15). Whether or not the driver has performed an emergency avoidance operation is based on the detection result of the steering angle sensor 4 serving as the operation input detection means, and the steering operation amount or the steering operation speed of the steering wheel is greater than a preset reference value. If it is greater than the reference value, it is determined that the driver has performed an emergency avoidance operation. When it is determined that the driver has performed an emergency avoidance operation (step # 15, Yes), the process proceeds to a brake force control means described later (step # 18).

  If the driver is not performing an emergency avoidance operation (step # 15, No), it is determined based on the calculated relative speed and FIG. 5 whether the vehicle is in the steering dominant region (step # 16). If the host vehicle is in the steering dominant region (step # 16, Yes), the process proceeds to a brake force control means described later (step # 18). Thus, when it is determined by the collision possibility determination means that there is a possibility of colliding with an obstacle, even if the driver is not performing a steering operation, the process proceeds to a brake force operation means described later, Under certain conditions, the brake 20 operates with a differential pressure.

  When the host vehicle is not in the steering dominant region (step # 16, No), the process proceeds to an automatic brake actuating means described later (step # 17). When it is determined that there is no possibility that the vehicle will collide with an obstacle (step # 13, No), and when the VSC is operating (step # 14, Yes), the automatic brake operation described later is performed. There is no transition to the means and the brake force control means. Even if the host vehicle is not in the steering dominant region (step # 16, No), it may be configured to shift to a brake force control means described later (step # 18). With this configuration, when an emergency avoidance operation is not performed, it is possible to shift to the braking force control means regardless of whether the steering dominant region or the braking dominant region.

[Automatic brake operation means]
The automatic brake actuating means will be described based on FIG. As shown in the flowchart of FIG. 7, when the automatic brake operating means is entered, threshold values L1 and L2 are calculated (step # 21). The threshold values L1 and L2 are calculated based on FIG. 5 described above. After the alarm device 10 automatically activates the brake 20 before the brake 20 is automatically activated, the brake 20 is automatically activated. For example, when the driver performs a braking operation or the like and the inter-vehicle distance L becomes a distance with a low possibility of a collision, the automatic operation of the brake 20 is released. In FIG. 7, the automatic brake actuating means is configured assuming that the obstacle is a moving object such as a preceding vehicle. When the obstacle is a stationary object, it is necessary to adopt different means. .

  It is determined whether or not the inter-vehicle distance L is shorter than the threshold value L1 (step # 22). If the inter-vehicle distance L is shorter than the threshold value L1, the alarm device 10 is automatically activated (step # 23). The alarm device 10 may be, for example, by automatically operating the brake 20 temporarily, for example, in addition to visually or audibly alerting the driver with a buzzer (not shown) or a display panel (not shown). You may comprise so that a driver | operator may be alerted.

  Next, it is determined whether or not the inter-vehicle distance L is shorter than the threshold value L2 (step # 24). If the inter-vehicle distance L is shorter than the threshold value L2 (step # 24, Yes), the brake 20 is automatically operated. (Step # 25). The brake pressure for automatically operating the brake 20 is from the ECU 8 via the brake control unit 11 so that the brake pressures of the brakes 20 of the respective wheels all have the same value as in the case of the normal operation of the brake 20 by the driver. Are output to the switching valve 27 and the pressure increasing valve 28.

  When the brake 20 is automatically operated, it is determined whether or not the inter-vehicle distance L is longer than the threshold value L1 (step # 27). If the inter-vehicle distance L is longer than the threshold value L1 (step # 27 / Yes), switching is performed. The valve 27 is switched and the automatic operation of the brake 20 is released (step # 28).

  When the inter-vehicle distance L is shorter than the threshold value L1 (step # 27 · No), the automatic operation of the brake 20 continues. The situation of the avoidance operation by the driver while the brake 20 is automatically operated is monitored (step # 26), and it is determined that the driver has performed the avoidance operation by steering based on the detection result of the steering angle sensor 4. If it is determined that the driver has performed an avoidance operation by braking based on the detection result of the pressure sensor 7 (step # 26, Yes), the automatic operation of the brake 20 is released. (Step # 28).

  Although not shown, when avoidance by steering by the driver is performed (step # 26 / Yes), it may be configured to shift to a brake force control means described later and operate the brake 20 with a differential pressure. . With such a configuration, the driver's steering avoidance can be assisted by the differential pressure operation of the brake 20.

  Although not shown, the threshold values L1 and L2 are calculated based on the vehicle speed of the host vehicle and the relative speed between the host vehicle and the obstacle. For example, when the relative speed is the same, the vehicle speed of the host vehicle is As the speed increases, the threshold values L1 and L2 become larger values, and the brake 20 and the alarm device 10 are configured to automatically operate when the inter-vehicle distance L is long. As shown in FIG. 5, for example, when the vehicle speed of the host vehicle is the same, the threshold values L1 and L2 become larger values as the relative speed increases, and the brake 20 And the alarm device 10 is configured to automatically operate.

[Brake force control means]
The brake force control means will be described based on FIGS. As shown in the flowcharts of FIGS. 8 and 9, when the brake force control means is entered, the eccentric amount between the host vehicle and the obstacle is calculated based on the detection result from the radar 2 (step # 31). Next, the avoidable direction determining means determines the avoidable direction based on the amount of eccentricity and the information detected by the camera 1 (step # 32), and the amount of eccentricity and relative speed are calculated by the above-described brake pressure calculation method. Then, the brake pressure to be applied to each wheel is calculated based on the vehicle speed or the like (step # 33). Although not shown, when the avoidable direction determining means determines that avoidance is impossible, the differential pressure operation of the brake 20 is not performed. 8 and 9, the automatic brake operation means is configured assuming that the obstacle is a moving object such as a preceding vehicle, and different means are adopted when the obstacle is a stationary object. There is a need.

  Next, threshold values L3 and L4 are calculated (step # 34). The threshold values L3 and L4 are calculated on the basis of FIG. 5 described above. After the alarm device 10 automatically operates, the driver is alerted prior to the differential pressure operation of the brake 20, and then the brake 20 It is comprised so that it can be operated.

  It is determined whether the inter-vehicle distance L is shorter than the threshold value L3 (step # 35). If the inter-vehicle distance L is shorter than the threshold value L3 (step # 35, Yes), the alarm device 10 is automatically activated (step # 35). Step # 36). Note that the alarm device 10 may, for example, temporarily activate the brake 20 or perform a difference in addition to visually or audibly alerting the driver with a buzzer (not shown) or a display lamp (not shown). You may comprise so that a driver | operator may be alerted by operating pressure.

  Next, it is determined whether or not the inter-vehicle distance L is shorter than the threshold value L4 (step # 37). If the inter-vehicle distance L is shorter than the threshold value L4 (step # 37, Yes), Based on the brake pressure of the brake 20, it is output from the ECU 8 via the brake control unit 11 to the switching valve 27, the pressure increasing valve 28 and the pressure reducing valve 29 of the brake 20 to operate the brake 20 with a differential pressure (step # 38). .

  When the brake 20 operates with a differential pressure, it is determined whether or not the vehicle has stopped based on the detection result of the vehicle speed sensor 5 and whether or not the inter-vehicle distance L is longer than the threshold value L3 (step # 39), and the vehicle stops. When it is determined that the vehicle distance L is longer than the threshold value L3 (step # 39, Yes), the switching valve 27 is switched and the differential pressure operation of the brake 20 is released. (Step # 40). Specifically, for example, when the driver performs a braking operation or the like and the inter-vehicle distance L becomes a distance with a low possibility of a collision, the differential pressure operation of the brake 20 is released.

  When it is determined that the inter-vehicle distance L is shorter than the threshold value L3 and the vehicle is not stopped (No in step # 39), the differential pressure operation of the brake 20 is continued. While the brake 20 is operating under differential pressure, immediately after the traveling direction of the host vehicle changes based on the detection results of the camera 1, the radar 2, the yaw rate sensor 3 and the like (the detection value of the yaw rate sensor 3 indicates the braking force control). When a new obstacle appears in front of the host vehicle immediately after the change by means (step # 41, Yes), the differential pressure operation of the brake 20 is immediately released (step # 40). Therefore, the differential pressure operation of the brake 20 with respect to the previous obstacle can be prevented from adversely affecting the response to the new obstacle, and the response to the new obstacle can be appropriately performed.

  In addition, while the brake 20 is operating the differential pressure, based on the detection result of the steering angle sensor 4, the driver steers the steering handle in a direction opposite to the avoidable direction in which the brake 20 is differentially operated. Even when the determination is made (step # 42, Yes), the differential pressure operation of the brake 20 is immediately released (step # 40). Therefore, it is possible to prevent interference between the direction of the steering operation of the driver and the generation direction of the turning moment due to the differential pressure operation of the brake 20.

  Also, when the vehicle on which the VSC operates is in an unstable posture while the brake 20 is operating with the differential pressure (step # 43 / Yes), the differential pressure operation of the brake 20 is immediately released (step # 43). Step # 40). Therefore, it is possible to prevent the vehicle from becoming unstable by operating the brake 20 with a differential pressure to generate a turning moment, and the vehicle posture can be stabilized by the VSC.

  Although not shown, the threshold values L3 and L4 are calculated based on the vehicle speed of the host vehicle and the relative speed between the host vehicle and the obstacle. For example, when the relative speed is the same, the vehicle speed of the host vehicle is high. Accordingly, the threshold values L3 and L4 become larger values, and the brake 20 and the alarm device 10 are configured to automatically operate when the inter-vehicle distance L is long. Further, as shown in FIG. 5, for example, when the vehicle speed of the host vehicle is the same, the threshold values L3 and L4 increase as the relative speed increases, and the brake 20 And the alarm device 10 is configured to automatically operate.

  For example, when the collision of an own vehicle with an obstacle is avoided by an automatic steering device (not shown), there is a possibility that the rotation of the steering wheel accompanying the operation of the automatic steering device interferes with the steering operation of the driver. is there. However, by configuring the brake force control means as described above, even if the driver recognizes the avoidance of the collision of the own vehicle with the obstacle by the differential pressure operation of the brake 20 and performs the steering operation, the brake force There is no interference between the differential pressure operation of the brake 20 by the control means and the steering operation of the driver. That is, unlike an automatic steering device that avoids a collision of an own vehicle with an obstacle by operating the steering handle itself, the brake force control means operates the differential pressure of the brake 20 as an operation input different from the steering operation. Thus, it is possible to avoid the collision of the own vehicle with the obstacle. Therefore, it is possible to realize an automatic braking device that respects the driving intention of the driver and can maintain a good driving feeling.

[Brake operation status by brake force control means]
The operation state of the brake 20 by the brake force control means will be described based on FIG. FIG. 10 shows that the driver performs emergency avoidance by steering at the same timing in the steering avoidance region under the same conditions of the vehicle speed, relative speed, inter-vehicle distance L, eccentricity (+ 50%), etc., and brake 20 Are respectively shown in FIG. 10 (A) and when the same brake pressure is applied to the brakes 20 of all the wheels by the automatic brake operating means (FIG. 10 (B)). 10 indicates an outline of the magnitude of the brake pressure of the brake 20 of each wheel, and the white arrow illustrated in FIG. 10 indicates the direction of the turning moment acting on the vehicle.

  As shown in FIGS. 10 (a) and 10 (b), the turning force is generated in the vehicle by the brake force actuating means, so that it is largely avoided in the right direction by the turning moment as compared with the case where the braking force control means is not provided. And collision with an obstacle can be reduced. Although not shown, when the amount of eccentricity is large, it is possible to avoid collision with an obstacle.

[First Alternative Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention], the example in which the brake force control means is configured as shown in the flowcharts of FIGS. 8 and 9 is shown, but the flowchart of FIG. 11 is adopted instead of FIG. May be.

  As shown in FIG. 11, when the brake force control means is entered, the eccentric amount between the host vehicle and the obstacle, the avoidable direction, the brake pressure, Threshold values L3 and L4 are calculated and judged (steps # 51 to # 54).

  Next, it is determined whether or not the calculated absolute value of the eccentric amount is equal to or greater than a predetermined value (for example, 75% or more) (step # 55). In step # 56, it is determined whether the vehicle can be avoided sideways in the avoidable direction without colliding with an obstacle based on the vehicle speed, the relative speed, and the inter-vehicle distance L. When it is determined that lateral avoidance is possible, the alarm device 10 is activated when the inter-vehicle distance L becomes shorter than the threshold value L3, as in [Best Mode for Carrying Out the Invention] described above (step # 57, # 58) When the value is shorter than the threshold value L4, the brake 20 operates under differential pressure under certain conditions (steps # 59 and # 38).

  As described above, the brake force control means applies the brake 20 only when it is determined that lateral avoidance is possible based on the positional relationship between the host vehicle and the obstacle with high possibility of lateral avoidance when the absolute value of the eccentricity is equal to or greater than a predetermined value. Is configured to operate with a differential pressure, a brake force control means for avoiding a collision can be realized.

  In the above-mentioned [Best Mode for Carrying Out the Invention], by increasing or decreasing the brake pressure of the brake 20 of each wheel to a predetermined pressure, a differential pressure is generated in the brake pressure of the brake 20 of each wheel. Although the example which comprised was shown, as shown in FIG. 12, you may comprise so that a brake coefficient may be set and a differential pressure may be produced in the brake pressure of the brake 20 of each wheel.

  Based on FIG. 12, an example of the brake coefficient for each eccentric amount in this embodiment will be described. As shown in FIG. 12A, for example, when the amount of eccentricity is + 50%, only the brake coefficient of the right front brake 20FR with respect to the brake pressure of the left rear, left front, and right rear brakes 20RL, 20FL, 20RR is obtained. The brake coefficient is set so that 6 times the brake pressure is applied. In this way, the ECU 8 is simplified while ensuring the stability of the rear wheels by generating the differential pressure of the brake pressure only in the left front and right front brakes 20FL and 20FR (front wheel brakes 20). be able to.

  As shown in FIG. 12B, for example, when the amount of eccentricity is + 50%, the brake pressures of the left rear, left front and right rear brakes 20RL, 20FL, and 20RR are not applied, and the brake is applied only to the right front brake 20FR. The brake coefficient may be set so that pressure is applied. Thus, ECU8 can be simplified by comprising so that brake pressure may be produced only in the right front brake 20FR.

  When the brake force actuating means is configured so as to avoid a collision based on FIG. 13 and the differential pressure of the brake pressure is generated only in the left front and right front brakes 20FL and 20FR shown in FIG. The operation state of the brake 20 will be described.

  FIG. 13 shows that the vehicle speed, the relative speed, the inter-vehicle distance L, the amount of eccentricity (+ 75%), etc. are the same, neglecting the steering avoidance in the steering avoidance region, the brake force control means is activated, and the brake 20 is operated with a differential pressure. The case (FIG. 13 (a)) and the case where the automatic brake actuating means is activated to apply the same brake pressure to the brakes 20 of all the wheels (FIG. 13 (b)) are shown. 13 indicates the outline of the magnitude of the brake pressure of the brake 20 of each wheel, and the white arrow illustrated in FIG. 13 indicates the direction of the turning moment acting on the vehicle.

  As shown in FIGS. 13 (a) and 13 (b), compared with the case where no braking force control means is provided, the turning force is generated in the vehicle by the braking force control means, so that the turning moment is avoided in the right direction. Can avoid collisions with obstacles.

[Second Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention] and [First Different Embodiment of the Invention], an example in which the possibility of a collision of an own vehicle with an obstacle is determined based on the graph of FIG. Although shown, the possibility of collision may be determined by a different method. An example in which the alarm device 10 and the brake 20 are operated automatically and differentially when the inter-vehicle distance L becomes shorter than the threshold values L3 and L4 after it is determined that there is a possibility of a collision. However, for example, the alarm device 10 and the brake 20 may be configured to automatically and differentially operate after elapse of a predetermined time after it is determined that there is a possibility of a collision.

  In the above-mentioned [Best Mode for Carrying Out the Invention] and [First Different Embodiment of the Invention], an example in which it is determined based on the detection result of the steering angle sensor 4 that the driver is not performing an avoidance operation. However, a different detection device (not shown) may be adopted as the operation input detection means. For example, the driver is based on the detection result of a foot brake sensor (not shown) that detects the stepping operation of the foot brake. However, a configuration for determining that the avoidance operation is not performed may be adopted.

  In the above-mentioned [Best Mode for Carrying Out the Invention] and [First Different Mode of Carrying Out the Invention], an example has been shown in which the amount of eccentricity is calculated based on the detection result of the radar 2 and the avoidable direction is determined. However, different detection devices (not shown) may be adopted as the positional relationship detection means. For example, the navigation system (not shown) and the inter-vehicle communication (system in which vehicles communicate with each other) are not limited to the radar 2 and the camera 1. , (Not shown) or the like, the avoidable direction may be determined.

[Third Another Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention], [First Alternative Embodiment of the Invention] and [Second Alternative Embodiment of the Invention], a differential pressure is generated in the brake pressure of the brake 20. In the above, an example in which the brake force control means is configured by causing a difference in brake force is shown, but a different configuration may be adopted as a configuration that causes a difference in brake force, for example, an electric brake (not shown) In some cases, a difference may be generated in the braking force by adjusting the amount of power supplied to an electric actuator (not shown) that operates the electric brake.

Vehicle block diagram Hydraulic circuit diagram of brake device Schematic explaining an example of eccentricity Map showing an example of brake coefficient Graph showing the relationship between braking avoidance distance and steering avoidance distance Flow chart showing the operating state of the automatic braking device Flow chart of automatic brake actuating means Flow chart of brake force control means Flow chart of brake force control means Schematic explaining the operating status of the brake Flowchart of brake force control means in the first alternative embodiment of the invention The map which shows an example of the brake coefficient in 1st another form of implementation of invention Schematic explaining the operating condition of the brake in 1st another form of implementation of invention

Explanation of symbols

2 Radar (positional relationship detection means)
2A radar (positional relationship detection means)
2B Radar (Positional relationship detection means)
2C radar (positional relationship detection means)
2D radar (positional relationship detection means)
4 Steering angle sensor (operation input detection means)
20 brake 20FL brake (front left)
20FR brake (front right)
20RL brake (left rear)
20RR brake (right rear)
VSC Vehicle Stabilization Controller L Distance between vehicles (actual distance)

Claims (4)

Collision possibility judging means for judging the possibility of collision of the own vehicle with an obstacle, operation input detecting means for detecting an operation input of the driver, and a position for detecting the positional relationship between the obstacle and the own vehicle in the left-right direction A relationship detection unit; an avoidable direction determination unit that determines an avoidable direction of the host vehicle based on a detection result of the positional relationship detection unit;
When it is determined by the collision possibility determination means that there is a possibility of collision with an obstacle, and the driver's operation input is not detected by the operation input detection means, the vehicle turns in the avoidable direction. A brake force control means for automatically operating the brake by causing a difference in the brake force of each wheel so as to enhance the performance. A vehicle stabilization control device for controlling the attitude of the vehicle by controlling the braking force based on the detection result of the operation input detection means;
2. The automatic braking device according to claim 1, wherein the braking force control means is configured so that the vehicle stabilization control device operates in preference to the braking force control means. Brake avoidance distance calculating means for calculating a braking avoidance distance to an obstacle capable of avoiding a collision with an obstacle of the own vehicle by braking, and steering to an obstacle capable of avoiding a collision of the own vehicle with the obstacle by steering Steering avoidance distance calculating means for calculating an avoidance distance; and automatic brake operating means for automatically operating a brake when the actual distance between the host vehicle and the obstacle is shorter than the steering avoidance distance and shorter than the braking avoidance distance; Prepared,
When the actual distance between the host vehicle and the obstacle becomes shorter than the steering avoidance distance at the relative speed between the host vehicle and the obstacle at which the braking avoidance distance is shorter than the steering avoidance distance, the brake force control unit is not activated. The automatic braking device according to claim 1, wherein the braking force control means is configured.   When the operation input of the driver is detected by the operation input detection means in a state where the brake is automatically operated by the automatic brake operation means, so as to cancel the automatic operation of the brake by the automatic brake operation means, 4. The automatic braking device according to claim 3, wherein said automatic brake operating means is constituted.

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