JPH0558257A - Vehicle automatic braking device - Google Patents

Abstract

(57) [Abstract] [Purpose] When the steering wheel is steered during automatic braking, the braking force is reduced or eliminated to prevent the steered wheels from slipping and prevent the driver from panicking. To improve running stability. [Configuration] It is premised that the distance and relative speed between the own vehicle and an obstacle are detected, the possibility of contact is determined from the detection result, and automatic braking is applied. The steering wheel steering detecting means for detecting the steering wheel steering of the driver and the lateral acceleration detecting means for detecting the lateral acceleration acting on the vehicle are provided. When the steering wheel is steered during the automatic braking operation, the control means 52 receiving the signals from the both detecting means controls the braking force to be reduced according to the magnitude of the lateral acceleration, or the automatic braking operation. When the steering wheel is steered more than a predetermined angle, the automatic braking is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a distance and a relative speed between a vehicle and an obstacle, judges the possibility of contact from the detection result, and automatically brakes each wheel. The present invention relates to the automatic braking device.

[0002]

2. Description of the Related Art Conventionally, as automatic braking devices for vehicles of this type, for example, Japanese Patent Publication No. 39-2565 and Japanese Patent Publication No.
As disclosed in Japanese Laid-Open Patent Publication No. 9-5668, the distance and relative speed between the own vehicle and an obstacle in front of the vehicle are continuously detected by using an optical method or ultrasonic waves, and the detected distance is detected. Judging whether there is a possibility of contact or not based on the distance and relative speed between the vehicle and the obstacle in front of it, and if it is determined that there is a possibility of contact, activate the actuator to automatically brake each wheel. It is known that a contact is prevented from being applied to the target.

[0003]

By the way, the above-mentioned automatic braking is activated when the vehicle approaches the obstacle ahead of the vehicle while the driver is not aware of it. Due to the characteristics of the tire, it becomes slippery. Therefore, when the driver notices an abnormal approach to the front obstacle during the automatic braking operation and steer the steering wheel, the front wheels as steered wheels may slip. In this case, it may be possible to prevent the steering wheel from turning into an unstable state by turning the steering wheel. However, if the driver does not work at all, the driver is likely to panic.

The present invention has been made in view of the above circumstances, and an object thereof is to reduce or eliminate the braking force and to steer the steered wheels when the steering wheel is steered during automatic braking. (EN) An automatic braking device for a vehicle, which can prevent the driver from falling into a panic state and can improve the running stability.

[0005]

In order to achieve the above-mentioned object, the invention according to claim 1 is an automatic braking device for a vehicle, and a detecting means for detecting a distance and a relative speed between the vehicle and an obstacle. A contact possibility determining means for determining whether or not there is a possibility of contact based on the distance and the relative speed between the vehicle and the obstacle detected by the detecting means, and the possibility of contact by the determining means. It is premised that an actuator that automatically brakes each wheel when it is determined to be present is provided. Further, the steering wheel steering detecting means for detecting the steering wheel steering of the driver, the lateral acceleration detecting means for detecting the lateral acceleration acting on the vehicle, the signals from the steering wheel steering detecting means and the lateral acceleration detecting means, and the actuator. When the steering wheel is steered during the operation of the automatic braking by, the control means for controlling to reduce the braking force according to the magnitude of the lateral acceleration is provided.

The invention according to claim 2 is premised on the same automatic braking device for a vehicle as the invention according to claim 1, and the difference from this is the steering wheel steering detecting means for detecting steering wheel steering of the driver and the steering wheel steering. And a control means for receiving a signal from the detection means and controlling the automatic braking to be released when the steering wheel is steered by a predetermined angle or more during the automatic braking operation by the actuator.

[0007]

With the above construction, in the invention according to claim 1,
When the driver steers the steering wheel during the operation of the automatic braking, the steering wheel steering detection means detects the fact, and the control means which receives a signal from the detection means detects the lateral acceleration of the vehicle detected by the lateral acceleration detection means. The braking force is controlled to be reduced according to the magnitude. As a result, the steered wheels do not slip and the steering wheel is effectively steered.

According to the second aspect of the present invention, when the driver steers the steering wheel at a predetermined angle or more during the operation of the automatic braking, the steering wheel steering detecting means detects that and receives a signal from the detecting means. The control means controls to release the automatic braking, so that the steering wheel does not slip and the steering wheel steering is effective, as in the case of the first aspect of the invention.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show an automatic braking device for a vehicle according to a first embodiment of the present invention, FIGS. 1 and 2 show a hydraulic circuit configuration of the automatic braking device, and FIG. 3 shows a block of the automatic braking device. The configuration is shown.

In FIGS. 1 and 2, reference numeral 1 is a master back for increasing the depression force of the brake pedal 2 by the driver,
Reference numeral 3 is a master cylinder that generates a braking pressure according to the stepping force increased by the master back 1. The braking pressure generated by the master cylinder 3 is first supplied to the automatic braking valve unit 4, and then, , ABS (anti-skid brake device) is supplied to the brake device 6 of each wheel through the valve unit 5.

The automatic braking valve unit 4 has a shutter valve 11, a pressure increasing valve 12 and a pressure reducing valve 1 which cut off the communication between the master cylinder 3 and the brake device 6.
3 and each of these three valves 11 to 13 is an electromagnetic 2-port 2-position switching valve. A motor-driven oil pump 14 and an accumulator 15 for storing the pressure oil discharged from the oil pump 14 and maintaining it at a constant pressure are interposed between the pressure increasing valve 12 and the master cylinder 3. It is set up. When the shutter valve 11 is in the open position, the brake pedal 2
Braking is applied by the brake device 6 of each wheel in accordance with the pedaling force of. On the other hand, when the shutter valve 11 is in the closed position,
When the pressure increasing valve 12 is switched to the open position and the pressure reducing valve 13 is switched to the closed position, the pressure oil from the accumulator 15 is supplied to the brake device 6 of each wheel for braking, and the pressure increasing valve 12 is moved to the closed position. When the pressure reducing valve 13 is switched to the open position, pressure oil is returned from the brake device 6 to weaken the braking. The switching of the three valves 11 to 13 is performed by an actuator 16 including a voltage source or the like for applying a voltage to each of them, and the actuator 16 is controlled by receiving a signal from a control box 17.

The ABS valve unit 5 has a 3-port 2-position switching valve 21 provided for each wheel, and the braking pressure applied to each braking device 6 by switching the valve 21 during braking. Is controlled so that each wheel does not lock. Although the structure of the ABS is not described in detail, a motor-driven oil pump 22 and accumulators 23 and 24 are provided in addition to the switching valve 21.
The brake device 6 for each wheel includes a disk 26 that rotates integrally with the wheel, and a caliper 27 that receives the braking pressure from the master cylinder 3 side and clamps the disk 26.

On the other hand, in FIG. 3, reference numeral 31 is an ultrasonic radar unit provided in the front portion of the vehicle body. The ultrasonic radar unit 31 is not shown in detail in the drawing, but as is well known, the ultrasonic wave is emitted from the transmitting portion. It is configured such that it transmits to an obstacle such as a vehicle in front of its own vehicle and receives a reflected wave reflected by hitting the front obstacle at a receiving unit, and a calculation for receiving a signal from this radar unit 31. The unit 32 is adapted to calculate the distance and relative speed between the host vehicle and the obstacle ahead by the delay time (Doppler shift) from the time when the radar received wave is transmitted. 33 and 3
Reference numeral 4 denotes a pair of radar head units provided on the left and right of the front portion of the vehicle body.
Reference numeral 34 denotes a configuration in which the pulsed laser light is transmitted from the transmission unit toward an obstacle in front of the own vehicle, and the reflected light reflected by the front obstacle is received by the reception unit. Reference numeral 32 denotes a signal processing unit 35 for processing signals from the radar head units 33 and 34.
The distance between the vehicle and the front obstacle and the relative speed are calculated according to the delay time from the transmission point of the laser reception light. And the arithmetic unit 32
Is configured to give priority to the calculation result of the distance and the relative speed by the system of the radar head units 33 and 34, and use the calculation result of the distance and the relative speed by the system of the ultrasonic radar unit 31 as an auxiliary. The above constitutes a distance / relative speed detecting means 36 for detecting the distance and relative speed between the vehicle and the obstacle ahead.

The transmission / reception direction of the pulsed laser light by both the radar head units 33, 34 is provided by a motor 37 so that it can be changed in the horizontal direction.
Is operated by the arithmetic unit 32. Reference numeral 38 denotes an angle sensor for detecting the transmission / reception direction of the pulsed laser light from the rotation angle of the motor 37. The detection signal of the angle sensor 38 is input to the arithmetic unit 32, and the radar head unit 33, The transmission / reception direction of the pulsed laser light is added to the calculation of the distance and the relative speed by the system of 34.

A lateral G sensor 40 is a lateral acceleration detecting means for detecting a lateral acceleration (lateral G) acting on the vehicle.
Reference numeral 41 is a steering angle sensor as steering wheel steering detecting means for detecting a steering angle of a driver, 42 is a vehicle speed sensor for detecting vehicle speed, 43 is a longitudinal G sensor for detecting longitudinal acceleration (longitudinal G) of the vehicle, and 44 is a road surface. A road surface μ sensor that detects a friction coefficient (μ), and these various sensors 40 to 4
The detection signal of No. 4 is input to the control unit 45 that controls the operation of the actuator 16. The control unit 45
A signal of the distance and the relative speed between the vehicle and the front obstacle obtained by the arithmetic unit 32 is also input to the control unit 17 (see FIG. 2). It is stored inside. Reference numeral 46 denotes an alarm display unit provided on an instrument panel in the vehicle compartment. The alarm display unit 46 is provided with an alarm buzzer 47 and a distance display unit 48 which receive signals from the control unit 45.

FIG. 4 shows a control flow of automatic braking for preventing contact by the control unit 45. In this control flow, first, after starting, various signals are read in step S1 and various threshold values L0 are read in step S2.
, L2, L3 are calculated. The threshold value L0 is the distance between the vehicle and the front obstacle at which there is a possibility of contact between the vehicle and the front obstacle, and automatic braking is started to prevent the contact. The threshold value L0 is calculated using a threshold value map as shown in FIG. The threshold value L2 is the distance between the vehicle and an obstacle ahead of the vehicle that issues an alarm prior to the start of automatic braking. The threshold value L2 for generating this alarm is greater than the threshold value L0 for starting automatic braking. Is also set larger by a predetermined amount. Further, the threshold value L3 is a distance between the vehicle and the front obstacle that releases the possibility of contact after the start of automatic braking and the automatic braking is released. The value is set to a value larger by a predetermined amount than the threshold value L0 for starting automatic braking, and in some cases, a value smaller by a predetermined amount.

The threshold map shown in FIG. 5 will now be described. In this map, the threshold line A is
When the vehicle ahead comes into contact with the obstacle ahead of the vehicle and stops, it indicates the inter-vehicle distance necessary to prevent contact with this vehicle, and the obstacle ahead always stops regardless of the magnitude of the relative speed V1. in a case ones (that is, when the relative speed V1 is equal to the vehicle speed v0) the same value as the (numeric expression v0 ^2/2 [mu] g)
Take The threshold line B indicates the inter-vehicle distance (numerical expression V1. (2v0-V1) / 2 .mu.g) required to prevent contact with this vehicle when the vehicle in front is fully braked, and the threshold line C Indicates the inter-vehicle distance required to prevent contact with the preceding vehicle when the preceding vehicle is subjected to slow braking of deceleration μ / 2g, and the threshold line D indicates this vehicle when the preceding vehicle maintains a constant vehicle speed. shows the inter-vehicle distance (numeric expression V1 ^2/2 [mu] g) required to prevent contact with. Further, the threshold line E indicates the inter-vehicle distance that can prevent the contact with the vehicle in front even if the own vehicle is automatically braked, but can reduce the impact force at the time of contact. In the case of this embodiment, the threshold line B is selected, and the threshold line B is used to determine the threshold value L0 corresponding to the current relative speed V1.

After the calculation of the various threshold values L0, L2 and L3, in step S3 the relative speed V1 between the vehicle and the front obstacle is calculated.
Is zero or more, that is, it is determined whether the two are approaching. When this determination is YES, it is further determined in step S4 whether or not the distance L1 between the vehicle and the front obstacle (hereinafter referred to as the inter-vehicle distance) is smaller than the alarm generation threshold L2. If the determination is YES, step S
Sound the alarm buzzer 47 at 5. Subsequently, in step S6, it is determined whether or not the inter-vehicle distance L1 is smaller than the threshold value L0 for starting automatic braking. When the determination is YES, full braking (braking force b1 in FIG. 6) is executed in step S7. Thus, the actuator 16 is operated to apply the automatic braking.

Subsequently, in step S8, it is determined whether or not the lateral acceleration detected by the lateral G sensor 40 is larger than a predetermined value c. If the determination is YES, the braking force for the automatic braking is determined in step S9. The value is reduced to a predetermined value (braking force b2 in FIG. 6), and then the process returns. On the other hand, the determination is NO
In case of, it returns immediately. When the determination in step S4 or S6 is NO, the process immediately returns without applying the automatic braking.

On the other hand, when the determination in step S3 is NO, that is, when the host vehicle and the front obstacle (front vehicle) are moving away from each other, in step S10 the inter-vehicle distance L1 is greater than the threshold L3 for releasing automatic braking. Determine if it is small. When this determination is YES, the state where the automatic braking is applied is left in step S11, and then it is determined in step S12 whether the lateral acceleration detected by the lateral G sensor 40 is larger than the predetermined value c. If the determination is YES, the braking force of the automatic braking is reduced to a predetermined value (braking force b2 in FIG. 6) in step S13, and the routine returns, while the determination is NO.
In case of, it returns immediately. When the determination in step S10 is NO, the automatic braking is released in step S14, and then the process returns.

Of the above control flow, particularly step S
When it is determined by 1 to S7, S10, S11, S14 whether there is a possibility of contact based on the vehicle-to-vehicle distance and the relative speed between the vehicle and the front obstacle, and when it is determined that there is a possibility of contact The contact possibility determination means 51 is configured to control the operation of the actuator 16 so as to automatically brake the vehicle. Further, in steps S8, S9, S12, and S13, when the steering wheel is steered during the operation of the automatic braking, the actuator 16 is actuated so as to reduce the braking force when the lateral G becomes a predetermined value c or more due to the steering. Braking force control means 52 for controlling
Is configured.

Next, the operation of the first embodiment, particularly the control of automatic braking for preventing contact by the control unit 45 in the control box 17, will be described. When L1 becomes smaller than the threshold value L0 for starting automatic braking, the control unit 45
The (contact possibility determination means 51) actuates the actuator 16 and switches the opening and closing of the valve in the automatic braking valve unit 4 via the voltage generated by the actuator 16. That is, while closing the shutter valve 11,
The pressure increasing valve 12 is switched to the open position and the pressure reducing valve 13 is switched to the closed position. As a result, the pressure oil from the accumulator 15 is supplied to the brake device 6 (caliper 27) of each wheel, and the operation of the brake device 6 causes the full braking force b1 to act on each wheel.
It is possible to prevent contact with a front obstacle.

When the driver steers the steering wheel during the operation of such automatic braking and the lateral acceleration exceeds the predetermined value c as the vehicle turns, the braking unit 45 (braking force control means 52) is used. The braking force is reduced from the full braking force g1 to the braking force g2.

In order to prevent the steered wheels from slipping, it is necessary that the lateral acceleration and the braking force acting on the steered wheels are within the region on the origin side of the curve T shown in FIG.
Further, in FIG. 6, b1 is a full braking force, and the lateral acceleration at the limit at which slip does not occur even at this full braking force b1 is a predetermined value c. Therefore, when the braking force is reduced from the full braking force b1 to the braking force b2 when the lateral acceleration becomes equal to or more than the predetermined value c as described above, the steered wheels will slip despite the steering wheel steering during automatic braking. Since it does not occur, it is possible to prevent the driver from falling into a panic state by ensuring a state where the steering wheel is effective, and it is possible to improve safety.

In the first embodiment, the threshold line B in FIG. 5 is used to obtain the threshold value L0 for starting automatic braking.
Was uniquely selected, and the threshold value L0 corresponding to the current relative speed V1 was obtained from this threshold line B. The present invention, in accordance with the vehicle speed v0 or the road condition, One threshold line is selectively selected from a plurality of threshold lines A to E, and a threshold value L0 corresponding to the current relative speed is selected from the selected threshold lines. You may.

In the first embodiment, the braking force control means 52 provides the full braking force (braking force) when the driver steers the steering wheel and the lateral acceleration acts on the vehicle by a predetermined value c or more. Although the control is performed so as to reduce from b1) to a predetermined amount (to the braking force b2), it is desirable to control the braking force so as to follow the curve T in FIG. 6 according to the magnitude of the lateral acceleration. ..

FIG. 7 shows a control flow of automatic braking for contact avoidance according to the second embodiment of the present invention. In this control flow, the first response is when the driver steers the steering wheel during automatic braking. Different from the case of the embodiment.

That is, after starting, first of all,
Various signals are read in step S21, and various thresholds L0, L2 and L3 are calculated in step S22. Then, in step S23, it is determined whether or not the relative speed V1 between the vehicle and the front obstacle is zero or more, that is, both are approaching. If this determination is YES, it is further determined in step S24 whether or not the inter-vehicle distance L1 between the vehicle and the front obstacle is smaller than the alarm generation threshold L2. If this determination is YES, In step S25, the alarm buzzer 47 sounds. Then, in step S26, it is determined whether or not the inter-vehicle distance L1 is smaller than the threshold value L0 for starting automatic braking.
In the case of S, the actuator 16 is operated so as to apply automatic braking with full braking in step S27.

Subsequently, in step S28, it is determined based on the signal from the steering angle sensor 41 whether or not the steering wheel steering angle θ0 is a predetermined value D or more. If the determination is YES,
In step S29, the automatic braking is released, and then the process returns. On the other hand, when the determination is NO, the process immediately returns. When the determination in step S24 or S26 is NO, the process immediately returns without applying the automatic braking.

On the other hand, when the determination in step S23 is NO, that is, when the own vehicle and the front obstacle (front vehicle) are moving away from each other, in step S30, the inter-vehicle distance L1 is greater than the automatic braking release threshold L3. Determine if it is small. If this determination is YES, the state where the automatic braking is applied is maintained in step S31, and then it is determined in step S32 whether the steering angle θ0 of the steering wheel is equal to or more than a predetermined value D or not. If the determination is YES, the automatic braking is released in step S33, and then the process returns, while if the determination is NO, the process immediately returns. When the determination in step S30 is NO, the automatic braking is released in step S34,
Then return.

Of the above control flow, particularly step S
When it is determined from 21 to S27, S30, S31, and S34 that there is a possibility of contact based on the inter-vehicle distance and relative speed between the vehicle and the front obstacle, and it is determined that there is a possibility of contact The contact possibility determination means 61 is configured to control the operation of the actuator 16 so as to automatically brake the vehicle. Further, the steps S28, S29, S32, S33 constitute a braking force control means 62 for controlling the automatic braking to be released when the steering wheel is steered by a predetermined angle D or more during the operation of the automatic braking.

Therefore, in the second embodiment,
When the driver steers the steering wheel at a predetermined angle D or more during the automatic braking operation, the automatic braking is released, so that the steered wheels do not slip and a state where the steering wheel is effective is ensured. As a result, as in the case of the first embodiment, it is possible to prevent the driver from falling into a panic state, and it is possible to improve safety.

[0034]

As described above, according to the automatic braking system for a vehicle of the present invention, when the driver steers the steering wheel during the automatic braking operation, the braking force is applied according to the magnitude of the lateral acceleration acting on the vehicle. By reducing or releasing the automatic braking, it is possible to prevent the steered wheels from slipping, and it is possible to secure a state where the steering wheel is effective and prevent the driver from falling into a panic state, It is possible to improve running stability or safety.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of an automatic braking device for a vehicle according to a first embodiment of the present invention.

FIG. 2 is a layout view of components of a hydraulic circuit of the automatic braking device.

FIG. 3 is a block configuration diagram of the automatic braking device.

FIG. 4 is a flowchart showing a control flow of automatic braking for preventing contact by a control unit.

FIG. 5 is a diagram showing a map for threshold value calculation.

FIG. 6 is a diagram showing a slip characteristic of steered wheels.

FIG. 7 is a view corresponding to FIG. 4, showing a second embodiment of the present invention.

[Explanation of symbols]

 6 Brake Device 16 Actuator 36 Distance / Relative Velocity Detection Means 40 Lateral G Sensor (Lateral Acceleration Detection Means) 41 Steering Angle Sensor (Handle Steering Detection Means) 51, 61 Contact Possibility Judgment Means 52, 62 Braking Force Control Means

Claims (2)

[Claims] 1. A detection means for detecting a distance and a relative speed between a vehicle and an obstacle, and a possibility of contact based on a distance and a relative speed between the vehicle and the obstacle detected by the detection means. A vehicle automatic braking device including a contact possibility determination means for determining whether or not there is a contact, and an actuator that automatically brakes each wheel when the determination means determines that there is a possibility of contact The steering wheel steering detecting means for detecting steering wheel steering of the driver, the lateral acceleration detecting means for detecting lateral acceleration acting on the vehicle, the signals from the steering wheel steering detecting means and the lateral acceleration detecting means, When the steering wheel is steered during the braking operation, the automatic braking of the vehicle is provided with a control means for controlling the braking force to be reduced according to the magnitude of the lateral acceleration. Location. 2. A detecting means for detecting a distance and a relative speed between the own vehicle and the obstacle, and a possibility of contact based on the distance and the relative speed between the own vehicle and the obstacle detected by the detecting means. A vehicle automatic braking device including a contact possibility determination means for determining whether or not there is a contact, and an actuator that automatically brakes each wheel when the determination means determines that there is a possibility of contact In the steering wheel steering detecting means for detecting the steering wheel steering of the driver, and receiving the signal from the steering wheel steering detecting means, when the steering wheel steering is performed by a predetermined angle or more during the automatic braking operation by the actuator, the automatic braking is released. An automatic braking device for a vehicle, comprising: