JP2008230295A - Braking force control device for vehicle - Google Patents

Abstract

An object of the present invention is to realize a vehicular braking force control device capable of surely notifying a driver that a vehicle may come into contact with an obstacle ahead in the traveling direction.
The present invention provides an obstacle detection means, a determination means, an alarm means for warning a driver when it is determined that there is a risk of contact, and a brake when it is determined that contact is inevitable. In the vehicular braking force control apparatus having the automatic braking operation means for operating the means, the warning means applies a deceleration generated by applying a braking force weaker than the braking force applied by the automatic braking operation means to the driver. It is a means to let you experience the alarm, comprising driving state determination means for determining whether the vehicle is in an acceleration state or a deceleration state, according to the driving state determined by this driving state determination means, The alarm means is characterized in that the content of the alarm is changed.
[Selection] Figure 2

Description

  The present invention relates to a vehicular braking force control apparatus, and more particularly to a vehicular braking force control apparatus that can reliably notify a driver that a vehicle may approach and contact an obstacle ahead in the traveling direction. .

  The vehicle detects obstacles ahead in the direction of travel of the vehicle with a radar device, etc., and if it is determined that there is a risk of contact with the obstacles, the driver is warned and contact with the obstacles cannot be avoided. In some cases, a vehicle braking force control device for operating the braking means is mounted.

In a conventional vehicle braking force control device, when it is determined that there is a possibility of contact with an obstacle, the brake fluid pressure is increased to generate a minute braking force, and then the brake fluid is increased until the braking force becomes zero. There is one that issues a warning to the driver by a small braking force by reducing the pressure.
JP 2003-306136 A

By the way, in the conventional vehicle braking force control device, when it is determined that there is a possibility of contact with an obstacle, the alarm means for giving an alarm to the driver is an alarm that generates a warning image display or an alarm sound by a buzzer. In addition to the means, there is an alarm means for operating a braking means and applying a light braking force (alarm brake) for warning to give a bodily sensation alarm due to deceleration.
As shown in FIG. 10, the alarm braking force pattern produced by the conventional alarm means is controlled in a constant continuous pattern regardless of the driving state. Therefore, the conventional warning based on the braking force when it is determined that there is a possibility of contact with an obstacle has applied a certain level of braking force so that the driver can experience the deceleration generated in the vehicle body. .
At this time, the strength of the braking force is limited to a light braking force because it is necessary that the warning braking force does not hinder driving. When the driving state of the vehicle is constant speed driving and neither acceleration nor deceleration is performed, the driver can feel a slight deceleration due to this light braking force, and the warning is effective.

However, for example, when the driver decelerates the accelerator pedal and accelerates, the vehicle is accelerating, and even if a slight braking force is applied in that situation, the acceleration is only slightly reduced. There was a problem that it was difficult to experience deceleration as a warning. Also, when the driver depresses the brake pedal and decelerates, the vehicle body is decelerating, so even if a slight deceleration due to the braking force for warning is added in that situation, driving There was a problem that it was difficult for people to experience.
In this way, the braking force for warning by the conventional vehicle braking force control device applies a constant braking force regardless of the driving operation situation of the driver. There was a problem that the user could not get a sense of the alarm and could not recognize the alarm, or it took time to recognize.

  The present invention is a vehicle braking force control device that can let a driver feel an alarm corresponding to a driving situation and reliably notify the driver that there is a risk of approaching and touching an obstacle. It aims to be realized.

  The present invention includes an obstacle detection means for detecting an obstacle ahead of the traveling direction of the vehicle, a determination means for determining whether or not contact with an obstacle can be avoided from a detection result detected by the obstacle detection means, When it is determined that there is a risk of contact by this determination means, an alarm means for warning the driver, and when the determination means determines that contact is unavoidable, automatic braking that activates the braking means In the vehicular braking force control apparatus having the actuating means, the warning means allows the driver to experience a deceleration generated by applying a braking force weaker than the braking force applied by the automatic braking actuating means. It is a means to make an alarm, and comprises an operating state determining means for determining whether the vehicle is in an accelerating state or a decelerating state, and the driving state determined by the operating state determining means is Flip, the said alarm means is characterized in that by changing the content of the alarm.

  The vehicular braking force control device of the present invention allows the driver to feel an alarm corresponding to the driving situation, so that the driver is informed that there is a risk of the alarm means operating, i.e., approaching an obstacle. It is possible to reliably notify.

The vehicular braking force control device according to the present invention reliably informs the driver that there is a possibility of contact with an obstacle by causing the driver to experience an alarm commensurate with the driving situation.
Embodiments of the present invention will be described below with reference to the drawings.

1 to 9 show an embodiment of the present invention. 1 is a system configuration diagram of a vehicle braking force control apparatus, FIG. 2 is a flowchart of braking force control, FIG. 3 is a time chart of a braking force pattern 1, FIG. 4 is a time chart of a braking force pattern 2, and FIG. FIG. 6 is a system configuration diagram showing a first modification of the vehicle braking force control device, FIG. 7 is a system configuration diagram showing a second modification of the vehicle braking force control device, and FIG. Is a time chart showing a first modification of the braking force pattern, and FIG. 9 is a time chart showing a second modification of the braking force pattern.
In FIG. 1, reference numeral 1 denotes a vehicle braking force control device. The vehicular braking force control device 1 includes a control unit 2, a radar device 3 as an obstacle detection means, a vehicle speed sensor 4, a brake pedal switch 5, an accelerator opening sensor 6, a brake control unit 7, a meter. 8 is connected.
The radar device 3 detects an obstacle ahead of the traveling direction of the vehicle by transmitting an electromagnetic wave such as a laser or a millimeter wave and receiving the reflected wave, and determines the distance to the obstacle and the relative speed with the obstacle. Measure and output to the control unit 2. The vehicle speed sensor 4 measures the speed (vehicle speed) of the host vehicle and outputs it to the control unit 2. The brake pedal switch 5 is turned on when the driver depresses the brake pedal. The accelerator opening sensor 6 measures the amount of depression of the accelerator pedal by the driver. The brake control unit 7 drives the brake actuator 9 according to a brake command from the control unit 2 and operates a brake 10 serving as a braking unit to generate a braking force. The meter 8 includes a display unit 11 that displays an alarm image in response to an alarm command from the control unit 2 and a buzzer 12 that generates an alarm sound.
The control unit 2 includes a determination unit 13, an alarm unit 14, and an automatic braking operation unit 15. The determination unit 13 determines whether or not contact with an obstacle can be avoided from the detection result detected by the radar device 3. If the determination unit 13 determines that there is a risk of contact with an obstacle, the alarm unit 14 issues an alarm to the driver with an alarm image or an alarm sound. When the determination means 13 determines that contact with an obstacle is unavoidable, the automatic braking operation means 15 outputs a brake command to the brake control unit 7 to drive the brake actuator 9 and serves as a braking means. The brake 10 is operated to generate a braking force.
The warning means 14 of the vehicle braking force control device 1 applies a braking force weaker than the braking force in the case where contact with an obstacle applied by the automatic braking operation means 15 cannot be avoided (alarm braking). This is a means for alerting the driver of the generated deceleration. The control unit 2 of the vehicle braking force control device 1 includes driving state determination means 16 that determines whether the vehicle is in an acceleration state or a deceleration state. The warning means 14 changes the content of the warning according to the driving state of the vehicle determined by the driving state determination means 16. In this embodiment, the alarm unit 14 changes a brake command (decompression command value or deceleration command value) for alarm output to the brake control unit 7 according to the driving state determined by the driving state determination unit 16. However, the braking force pattern and braking amount of the alarm brake are changed.

Next, the operation will be described.
As shown in FIG. 2, the vehicle braking force control device 1 has established a warning brake start condition for applying a braking force for warning when there is control (S01) (there is a risk of contact with an obstacle). Is determined (S02). This judgment is generally based on distance from obstacles and relative speed,
Formula ......... Predicted contact time = distance / predicted contact time represented by relative speed is calculated, and the condition that the value is equal to or less than a value determined as “high possibility of contact” is applied. This determination (S02) is repeated until the warning brake start condition is satisfied (S02: YES).
If the alarm brake start condition is satisfied (there is a risk of contact with an obstacle) and the determination (S02) is YES, it is determined whether the brake pedal switch 5 is ON (S03). This determination (S03) determines whether the driver is stepping on the brake pedal.
When the brake pedal switch 5 is ON and the determination (S03) is YES, the brake 10 is started by operating the alarm brake 10 with the braking force pattern 1 (FIG. 3) suitable for the situation where the brake pedal is depressed. Is applied (S04), and it is determined whether the warning brake end condition is satisfied (S05). This determination (S05) is generally applied under the condition that the predicted contact time is equal to or greater than the value determined as “no longer possible to contact”.
If the alarm brake end condition is satisfied (there is no risk of contact with an obstacle) and the determination (S05) is YES, the operation of the alarm brake 10 is canceled to remove the braking force (S06) and control To end (S07). If the warning brake end condition is not satisfied (there is a possibility of contact with an obstacle) and the determination (S05) is NO, the process returns to the determination (S02).
If the brake pedal switch 5 is not ON and the determination (S03) is NO, it is determined whether the accelerator opening detected by the accelerator opening sensor 6 is equal to or greater than a specified value (S08). This determination (S08) determines whether the driver is accelerating by depressing the accelerator pedal.
When the accelerator opening is equal to or greater than the specified value and the determination (S08) is YES, the operation of the brake 10 for alarm is started with the braking force pattern 2 (FIG. 4) suitable for the situation where the accelerator pedal is depressed more than the specified value. Then, the braking force is applied (S09), and it is determined whether the warning brake end condition is satisfied (S05).
When the alarm brake end condition is satisfied and the determination (S05) is YES, the operation of the alarm brake 10 is canceled to eliminate the braking force (S06), and the control is ended (S07). If the warning brake end condition is not satisfied and the determination (S05) is NO, the process returns to the determination (S02).
When the accelerator opening is less than the specified value and the determination (S08) is NO, the brake 10 for alarm is operated with the braking force pattern 3 (FIG. 5) suitable for the situation where the accelerator pedal is not depressed more than the specified value. Is started and a braking force is applied (S10), and it is determined whether a warning brake end condition for eliminating the braking force for warning is satisfied (S05).
When the alarm brake end condition is satisfied and the determination (S05) is YES, the operation of the alarm brake 10 is canceled to eliminate the braking force (S06), and the control is ended (S07). If the alarm brake end condition is not satisfied and the determination (S05) is NO, the process returns to determination (S02).
As described above, the vehicle braking force control apparatus 1 operates by changing the braking force pattern for warning according to the driving operation status of the driver by the control of the flowchart. It becomes possible.

Here, the braking force patterns 1 to 3 will be described.
FIG. 3 is a time chart of the brake fluid pressure command value or the deceleration command value of the braking force pattern 1 when the brake pedal switch 5 is ON.
(1) Braking force pattern 1
The braking force pattern 1 is a pattern suitable for a situation where the brake pedal is depressed, and is as follows as compared with the other braking force patterns 2 and 3.
・ Waveform: Pulse shape ・ Amplitude: Medium ・ Period: Short (compared to braking force pattern 2)
・ Duty ratio: High (compared to braking force pattern 2)
This is a situation where the driver depresses the brake pedal, and a deceleration has already occurred in the vehicle body or a deceleration will occur in the future. This is because it is difficult to experience with the braking force of. Therefore, in a situation where the driver is depressing the brake pedal, a braking force is applied in the form of a pulse so that the driver can experience even when the vehicle body deceleration due to the depression of the brake pedal occurs.
Even with a pulsed braking force, if the amplitude is increased (as in braking force pattern 2), a large pulsed deceleration will occur, resulting in a deceleration caused by the driver's depression of the brake pedal. On the other hand, a large deceleration will occur, which may affect driving. In addition, when the braking force is a pulse with a short cycle, vibration of the brake hydraulic system is transmitted to the brake pedal, and there is a possibility that the vibration can be recognized.
For the above reasons, the braking force pattern 1 suitable for the situation where the driver is stepping on the brake pedal is a pulse-like braking force with a short cycle and a medium amplitude.

(2) Braking force pattern 2
The braking force pattern 2 is a pattern suitable for a situation where the accelerator pedal is depressed more than a predetermined value, and is as follows compared with other patterns.
・ Waveform: Pulse shape ・ Amplitude: Large ・ Period: Long (compared to braking force pattern 1)
・ Duty ratio: Low (compared to pattern 1)
The braking force pattern 2 is a pulsed braking force and has a longer cycle than the braking force pattern 1 and a larger amplitude. This is a situation where the driver is depressing the accelerator pedal, and since acceleration has already occurred in the vehicle body or will occur in the future, acceleration by braking with a continuous command such as the braking force pattern 3 does not occur. This is because it is slightly reduced and is difficult to experience. Therefore, in situations where the driver is depressing the accelerator pedal, applying a braking force in a pulsed manner and increasing the amplitude will generate a certain large deceleration in a pulsed manner, even if the vehicle is accelerating at that time. It is possible to recognize that a braking force has been applied.
Compared with braking force pattern 1, braking force pattern 2 has a longer pulse period and a lower duty ratio by an amount corresponding to an increase in amplitude, thereby shortening the total application time and reducing it by a warning braking force. The time integration amount (that is, the speed reduction amount) of the speed is not increased, and the trouble to the operation is eliminated.
For the above reasons, the braking force pattern 2 suitable for the situation where the driver depresses the accelerator pedal more than a specified value is a pattern with a long period and a large amplitude with a pulsed braking force.

(3) Braking force pattern 3
The braking force pattern 3 is a pattern suitable for a situation where the brake pedal is not depressed and the accelerator pedal is not depressed more than a predetermined value, and is as follows.
・ Waveform: Continuously applied ・ Amplitude: Small ・ Period: −
・ Duty ratio:-
When the driver does not depress the brake pedal and does not depress the accelerator pedal more than a predetermined value, the vehicle is considered to be in a constant speed traveling state. In that case, the driver can recognize a warning if it occurs even with a slight deceleration, so that the continuous pattern has a low amplitude. In the case of a continuous braking force pattern, there is no sudden change in deceleration, so that it is difficult to affect driving.
For the above reasons, the braking force pattern 3 suitable for the situation where the driver does not depress the brake pedal and the accelerator pedal does not depress the predetermined value or more is a continuous braking force with a small amplitude pattern. .

Thus, the vehicle braking force control device 1 selects and operates the warning braking force pattern according to the driving operation situation of the driver. To distinguish the braking force pattern, the following items are changed for the waveform of the applied brake fluid pressure command value or the vehicle body deceleration command value.
・ Waveform: Continuously applied / pulsed amplitude ・ Amplitude: Hydraulic pressure value or amplitude of deceleration ・ Period: Pulsed braking force cycle ・ Duty ratio: Pulsed braking force per cycle applied The ratio of the on (ON) time to the non-applied (0FF) time. This vehicle braking force control device 1 is capable of controlling alarms suitable for the driving operation status of the driver by the above control. Power can be applied, it can function as an alarm, and control that does not hinder driving is possible.

As described above, the vehicle braking force control device 1 causes the driver to experience a deceleration generated by applying a braking force weaker than the braking force applied by the automatic braking operation unit 14 to give an alarm to the driver 13. And an operating state determining means 15 for determining whether the vehicle is in an accelerating state or a decelerating state. According to the operating state determined by the operating state determining means 15, the alarm means 13 provides an alarm. The contents have been changed.
As a result, the vehicular braking force control device 1 can allow the driver to feel an alarm commensurate with the driving situation, so that there is a possibility that the alarm means 13 is activated, that is, there is a risk of approaching an obstacle. The driver can be surely notified.
The warning means 13 may change the braking force pattern and the braking amount according to the driving state determined by the driving state determination means 15, indicating that there is a risk of contact with an obstacle under various driving conditions. The change of the braking force pattern and the braking amount only changes the specification of the braking force control in the control device, so that a detailed alarm corresponding to the vehicle is realized. be able to.

The present invention is not limited to the above-described embodiments, and various application modifications can be made. For example, in the vehicle braking force control apparatus of the above-described embodiment, the brake pedal switch 5 and the accelerator opening sensor 6 are connected to the control unit 2, but it is also conceivable to connect other switches and sensors.
FIG. 6 shows a first modification of the vehicle braking force control apparatus. This vehicle braking force control device 1 is provided with an acceleration sensor 17 instead of the brake pedal switch 5 and the accelerator opening sensor 6. The vehicular braking force control device 1 determines whether an acceleration or deceleration occurs in the vehicle based on a signal from the acceleration sensor 17 and changes the applied braking force pattern. Therefore, it is possible to let the driver experience an alarm that more appropriately matches the driving situation.

FIG. 7 shows a second modification of the vehicle braking force control apparatus. The vehicle braking force control device 1 changes a warning braking force pattern depending on the vehicle status in addition to the driving operation status of the driver.
This vehicular braking force control device 1 includes a steering rudder angle sensor 18, a yaw rate sensor 19, a wiper switch 20, a window control device 21, an air conditioner instead of the brake pedal switch 5 and the accelerator opening sensor 6. 22 and the audio device 23 are newly connected. These sensors / devices 18 to 23 are used as information sources for detecting the following state and selecting a braking force turn suitable for the state. The vehicle braking force control device 1 can provide all or a part of these sensors and devices 18 to 23, and can determine a warning braking force pattern based on information accompanying the sensors or devices 18-23.
(1) Steering angle sensor 18
Information indicating the steering amount of the steering wheel is obtained, and it is possible to determine whether the vehicle is turning. While the vehicle is turning, sudden acceleration / deceleration changes may cause a decrease in vehicle stability and may cause the driver to feel uncomfortable, so the warning braking force also changes abruptly. It must be a pattern that does not.
(2) Yaw rate sensor 19
Information indicating the yaw rate of the vehicle is obtained, and it is possible to determine whether the vehicle is turning as with the steering angle.
(3) Wiper switch 20
Information indicating the operation status of the wiper is obtained, and it can be determined that the weather is bad. In case of rain, it is expected that the road surface friction coefficient will decrease, so sudden changes in acceleration / deceleration may cause a decrease in vehicle stability or cause the driver to feel uncomfortable. Therefore, it is necessary that the warning braking force does not change abruptly.
(4) Others Vehicle speed sensor 4: Obtains information indicating the speed of the vehicle. When the speed is high, it is determined that there is a possibility that a large noise such as a running sound or an engine sound is generated.
Window control device 21: Obtains information indicating whether the vehicle window is fully closed or vacant. When the window is open and the vehicle speed is high, it is determined that a running sound or engine sound enters the passenger compartment and it is difficult to hear the sound alarm.
Air conditioner 22: Obtains information indicating the air volume setting state of the air conditioning fan. When the air volume is large, it is determined by a blowing sound that it is difficult to hear a sound alarm.
Audio device 23: Obtains information indicating the audio volume setting state. If the volume is high, it is determined by the sound of the audio that the sound alarm is difficult to hear.
When the vehicle braking force control device 1 determines that the other information in the vehicle interior is loud and the alarm sound cannot be heard based on the above information, the warning braking force becomes more important and the driving force is increased. For example, it is conceivable to use a pattern having a large amplitude so that the deceleration is larger than usual.
The vehicular braking force control device 1 is applied in consideration of whether the vehicle is turning, the road surface friction coefficient is low, a large noise is generated, or a sound alarm is difficult to hear. The braking force pattern to be changed can be changed, and the driver can be made to experience an alarm that more appropriately matches the driving situation.

Moreover, although the braking force pattern of the above-mentioned embodiment repeats the same waveform, not only the same waveform is repeated but also a pattern that changes with time can be considered.
FIG. 8 shows a first modification of the braking force pattern. The braking force pattern 1 of the first modified example shown in FIG. 8 is obtained by changing the amplitude with time. In the first stage of alarm, the amplitude is increased to make the driver aware, and thereafter the amplitude is decreased. As a result, in the initial stage, the driver can feel a strong deceleration, so that quick recognition is possible. The reason why the amplitude is decreased with time is to prevent the operation from being hindered by making the time-integrated amount of deceleration, that is, the speed decrease amount constant.

  FIG. 9 shows a second modification of the braking force pattern. The braking force pattern 2 of the 2nd modification shown in FIG. 9 changes a period with time. In the first stage of the alarm, the cycle is shortened to make the driver aware, and thereafter the cycle is lengthened. As a result, at the initial stage, the driver can experience a vibrational deceleration, thereby enabling quick recognition. The reason why the cycle is lengthened with time and the duty ratio is lowered is to prevent a trouble in operation by making the amount of time integration of deceleration, that is, the speed reduction amount constant.

  The vehicular braking force control device according to the present invention reliably informs the driver that there is a risk of contact with an obstacle by letting the driver experience an alarm commensurate with the driving situation. It can be applied not only to a wheeled vehicle but also to a two-wheeled vehicle.

1 is a system configuration diagram showing an embodiment of a vehicle braking force control apparatus. It is a flowchart of braking force control. 2 is a time chart of a braking force pattern 1; 6 is a time chart of a braking force pattern 2; 6 is a time chart of a braking force pattern 3; It is a system configuration figure showing the 1st modification of the braking force control device for vehicles. It is a system block diagram which shows the 2nd modification of the braking force control apparatus for vehicles. It is a time chart which shows the 1st modification of a braking force pattern. It is a time chart which shows the 2nd modification of a braking force pattern. It is a system block diagram which shows the prior art example of the braking force control apparatus for vehicles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle braking force control apparatus 2 Control part 3 Radar apparatus 4 Vehicle speed sensor 5 Brake pedal switch 6 Accelerator opening sensor 7 Brake control part 8 Meter 9 Brake actuator 10 Brake 11 Display part 12 Buzzer 13 Judgment means 14 Alarm means 15 Automatic braking Actuating means 16 Operating state determining means

Claims (2)

Obstacle detection means for detecting an obstacle ahead of the direction of travel of the vehicle;
A determination means for determining whether or not contact with an obstacle can be avoided from the detection result detected by the obstacle detection means;
If it is determined that there is a risk of contact by this determination means, alarm means for warning the driver;
In the vehicular braking force control device including the automatic braking operation unit that operates the braking unit when the determination unit determines that contact is unavoidable,
The warning means is a means for causing a driver to experience a deceleration generated by applying a braking force weaker than the braking force applied by the automatic braking operation means, and making an alarm.
Comprising driving state determination means for determining whether the vehicle is in an acceleration state or a deceleration state;
The vehicular braking force control apparatus according to claim 1, wherein the warning means changes the content of the warning according to the driving state determined by the driving state determination means.   2. The vehicular braking force control apparatus according to claim 1, wherein the warning unit changes a braking force pattern and a braking amount in accordance with the driving state determined by the driving state determination unit.

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