JPH09286313A - Vehicle collision preventing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably announce a properly strong alarm to a driver by a method wherein a means to detect a car speed is provided, and an alarm decelerating means reduces a car speed such that the more a car speed is higher, the more deceleration of the vehicle is increased, and an alarm is generated. SOLUTION: An electronic control device 6 contains a collision prediction part 6a and a brake control part 6b, predict collision with a front obstacle, and a command to effect gentle brake is outputted to a brake device (an alarm deceleration means) 8. Namely, the collision prediction part 6a receives information from an obstacle sensor 2 and a car speed sensor 4 and calculates a distance to an obstacle, a relative speed, and a time until collision occurs. When the time until collision occurs is reduced to a value below a specified value, an alarm brake is operated. A car speed is detected by a car speed sensor 4 and vehicle deceleration is calculated. Braking is then applied on each wheel by a switching valve and alarm brake is worked. In this case, since a valve opening time is set according to a car speed so that a driver feels the same deceleration shock, an alarm is reliable recognized regardless of a car speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle collision prevention device.

[0002]

2. Description of the Related Art Conventionally, when an obstacle detecting means for detecting an obstacle is used to confirm an obstacle in front of (or behind) a vehicle, braking is automatically performed based on the information to avoid a collision. Vehicle collision prevention devices have been developed that include a warning deceleration unit that reduces the vehicle speed and issues a warning to the driver. This device detects the distance and relative speed between an obstacle and the vehicle by using a radar device that uses radio waves or light. Further, the braking distance is detected from the traveling speed of the vehicle, the road surface condition, etc., and it is determined whether there is a risk of collision. Then, collision avoidance measures such as automatically operating the braking device are taken.

At this time, if sudden braking is performed immediately because there is a risk of collision, the driver may not be ready because of sudden braking, and the posture may be lost. Therefore, before applying the sudden braking, a warning is given in advance to prompt the driver to perform a collision avoidance operation. This warning may be a buzzer sound or a deceleration shock caused by the operation of the braking device. However, despite the fact that the driver has already recognized the presence of a vehicle (obstacle) in front of him due to an erroneous warning or a traffic jam, the trouble of frequent warnings or the impact mitigation at the time of an actual collision can be reduced. Considering the aspect, the warning by the operation of the braking device is more effective.

Japanese Unexamined Patent Publication No. 54-33444 discloses that a driver is warned by applying gentle braking (weak braking) before the distance between a vehicle and an obstacle reaches a distance requiring sudden braking. Is disclosed.

Further, Japanese Patent Laid-Open No. 5-310110 discloses that
Further, the deceleration of the vehicle is kept substantially constant by changing the rate of increase of the braking fluid pressure of the automatic braking device for avoiding contact with the front obstacle, so that a substantially constant braking deceleration is achieved. It is disclosed to prevent the occurrence of.

[0006]

However, in the prior art disclosed in Japanese Unexamined Patent Publication No. 5-310110, the vehicle deceleration is always kept constant by the relatively gentle braking, and therefore the warning is given. The driver may not be able to recognize the warning due to the slow braking.

That is, if the vehicle deceleration due to braking is always constant, for example, during low speed traveling, even if the braking shock due to slow braking is at an appropriate level as a warning to the driver, during high speed traveling, the braking There was a problem that the shock was almost unknown to the driver and there was no meaning as a warning.

The present invention has been made in view of the above-mentioned problems of the prior art, and makes the driver feel a deceleration shock that is substantially equal to the driver regardless of the vehicle speed, so that the driver can be surely and reasonably strong. It is an object of the present invention to provide a vehicle collision prevention device that can give a warning about the height.

[0009]

SUMMARY OF THE INVENTION The present invention, as shown in FIG. 1 in its gist, is an obstacle detecting means for detecting an obstacle,
A vehicle collision prevention device comprising: a warning deceleration means for issuing a warning to the driver by reducing the vehicle speed based on the information of the obstacle detection means; and a means for detecting the vehicle speed, wherein the warning deceleration means is provided. However, the above problem is solved by generating the warning by decreasing the vehicle speed so that the vehicle deceleration increases as the vehicle speed increases.

According to the present invention, since the vehicle deceleration is changed according to the vehicle speed, the driver can feel the same deceleration shock regardless of the vehicle speed, and the warning can be surely recognized.

[0011]

A preferred embodiment is that deceleration by the warning deceleration means is realized by causing the braking device to generate a braking force so that the vehicle deceleration increases as the vehicle speed increases.

Another preferred embodiment further comprises automatic shifting means capable of shifting down by automatic shifting, and the deceleration by the warning decelerating means shifts down in addition to the normal automatic shifting control according to the vehicle speed. That is, the deceleration realized by the above is used together.

As a result, a large vehicle deceleration can be easily achieved even at a high speed, and a warning can be surely issued. Further, since the gear is shifted to a lower speed, it is possible to favorably cope with either sudden deceleration or sudden acceleration when avoiding an obstacle.

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

FIG. 2 is a block diagram showing an outline of the vehicle collision prevention device according to the present invention.

In FIG. 2, an obstacle sensor (obstacle detecting means) 2 is a radar device provided at the front of the vehicle. The obstacle sensor 2 transmits waves such as laser and millimeter waves from an emission unit toward an obstacle such as a vehicle ahead and receives a reflected wave reflected by the obstacle at a reception unit. . The vehicle speed sensor 4 is a sensor that detects the vehicle speed of the host vehicle.

The electronic control unit 6 includes a collision prediction unit 6a and a braking control unit 6b. That is, the electronic control unit 6 takes in information from the sensors 2 and 4, predicts a collision with a front obstacle, and gives a warning to the driver. Therefore, the braking device (warning deceleration means) 8 is gently braked. Issue a command to do.

FIG. 3 shows a hydraulic circuit schematically showing the braking device 8. As shown in FIG. 3, in the present embodiment, the hydro-booster system is used so that the four wheels can be fully braked even when the driver does not perform a braking operation.

In FIG. 3, when the brake pedal 10 is stepped on, the booster 12 amplifies the pedaling force, and in response, hydraulic pressure is generated in the master cylinder 14. The hydraulic pressure generated in the master cylinder 14 is applied to the P & B valve (proportioning and bypass valve) 16 and the switching valve SA.
It is transmitted to the front wheel cylinder FW and the rear wheel cylinder RW via 1, SA2 and SA3, respectively.

The booster 12 is a hydro booster,
The hydraulic pressure accumulated in the accumulator 18 is used as an assisting force. The hydraulic pressure of the accumulator 18 is guided to the booster 12 through the liquid passage 20. The pump 22 pumps the oil liquid from the reservoir 24 and stores the pressure in the accumulator 18.

ABS (anti-skid brake system), TRC (traction control), V
At the time of controlling SC (vehicle stability control), etc., switching valves SA1, SA2, SA3, SAR and control valves SF1, SF2, SF3, SF4, SR1, SR
The hydraulic pressure of each wheel cylinder FW, RW is controlled by appropriately controlling the switching of 2, SR3, SR4.

Further, in the present invention, automatic braking is performed regardless of the driver's intention when the brake pedal 10 is not depressed, as in the case of performing gentle braking (warning brake) to give a warning to the driver. Accumulator 1
Utilizing the hydraulic pressure accumulated in 8. That is, the switching valve STR is switched to guide the hydraulic pressure of the accumulator 18 to the switching valves SA1, SA2 and SA3 through the liquid passage 26. Switching valve SA
By switching between 1 and SA2, this hydraulic pressure is introduced to the front wheel cylinder FW. Similarly, the switching valve SA
By switching No. 3, the hydraulic pressure is guided to the rear wheel cylinder RW.

In this embodiment, the braking device 8 of the VSC type hydro booster system is used as the warning deceleration means, but the present invention is not limited to this, and the deceleration is performed regardless of the driver's intention. It is clear that any system capable of

The operation of this embodiment will be described below with reference to the flowchart of FIG. 4 and the control conceptual diagram of FIG.

At the position P0 in FIG. 5, when the obstacle sensor 2 catches the obstacle OB ahead, step 10 in FIG.
At 0, obstacle determination processing is performed. Collision predicting unit 6a
Is the time required for a collision (collision time) when the vehicle receives the information from the obstacle sensor 2 and the vehicle speed sensor 4 and travels at the distance to the obstacle OB, the relative speed, and the same speed.
Calculate t etc.

As shown by the position P1 in FIG. 5, the warning brake is actuated when the time until the collision becomes T1 or less is the warning brake actuation timing.

In step 120, the vehicle speed ak is detected, and in step 130, the vehicle deceleration bk is calculated from the vehicle speed ak using the map shown in FIG. The map of FIG. 6 is created from the graph of FIG. 7 showing the relationship between vehicle speed and vehicle deceleration. The graph of FIG. 7 is obtained by an experiment in which the vehicle deceleration bk at which the driver feels the same deceleration shock at each vehicle speed ak is obtained. As shown in the graph of FIG. 7, the higher the vehicle speed ak, the larger the deceleration bk. Vehicle deceleration b
When k is obtained, the valve opening time tk corresponding to it is determined.

At step 140, the switching valve STR,
When SA1, SA2, and SA3 are opened for the valve opening time tk, the accumulated pressure of the accumulator 18 is introduced into the wheel cylinders FW and RW through the liquid passage 26. As a result, each wheel is braked according to the valve opening time tk, and the warning brake is activated.

At this time, since the valve opening time tk is set according to the vehicle speed ak so that the driver feels the same deceleration shock, the driver can surely recognize the warning regardless of the vehicle speed ak. .

At the time of high vehicle speed, it is more efficient to use not only deceleration by the warning brake but also downshifting by the automatic transmission means (which may be a known automatic transmission). That is, since the engine brake is increased (decelerated) due to the downshift, the wheel cylinder F is correspondingly increased.
The same deceleration shock can be obtained even if the amount of pressure increase to W and RW is reduced. Further, since the gear is shifted to a lower speed, the effect of the next sudden braking can be further enhanced. Depending on the situation, it may be necessary to accelerate suddenly in order to avoid obstacles, but in that case as well, a higher acceleration performance can be obtained as compared with the case where the gear position is decelerated as it is.

If the driver takes no measures despite the warning, when the avoidance limit P2 (T2 time until collision) shown in FIG. 5 is reached, full braking is automatically applied to all wheels. Stop the vehicle to avoid a collision. Obstacle OB
Even if the vehicle reaches the existing point P3 of the vehicle, the vehicle speed has dropped due to the warning brake and the full braking, so the impact can be reduced.

[0032]

As described above, according to the present invention,
Since the vehicle deceleration when applying the warning brake is changed according to the vehicle speed, the driver can always feel the same deceleration shock regardless of the vehicle speed, and the warning can be reliably recognized. An effect that reliability is improved can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is a block diagram schematically showing a vehicle collision prevention device according to this embodiment.

FIG. 3 is a hydraulic circuit diagram showing an outline of a braking device according to the present embodiment.

FIG. 4 is a flowchart showing braking control according to the present embodiment.

FIG. 5 is a conceptual diagram showing braking control according to the present embodiment.

FIG. 6 is a map for calculating vehicle deceleration for warning from vehicle speed.

FIG. 7 is a graph showing a relationship between a vehicle speed and a vehicle deceleration that would receive an equivalent deceleration shock.

[Explanation of symbols]

 2 ... Obstacle sensor 4 ... Vehicle speed sensor 6 ... Electronic control device 6a ... Collision prediction unit 6b ... Braking control unit 8 ... Braking device 10 ... Brake pedal 12 ... Booster 14 ... Master cylinder 16 ... P & B valve 18 ... Accumulator 20, 26 ... Liquid path 22 ... Pump 24 ... Reservoir OB ... Obstacle STR, SA1, SA2, SA3 ... Switching valve SF1, SF2, SF3, SF4, SR1, SR2, SR3, SR4 ... Control valve

Claims (3)

[Claims] 1. A vehicle collision including obstacle detection means for detecting an obstacle, and warning deceleration means for issuing a warning to a driver by reducing the vehicle speed based on the information of the obstacle detection means. A vehicle collision prevention device, characterized in that the prevention device includes means for detecting a vehicle speed, and the warning deceleration means issues the warning by decreasing the vehicle speed so that the vehicle deceleration increases as the vehicle speed increases. . 2. A vehicle collision according to claim 1, wherein deceleration by the warning deceleration means is realized by causing a braking device to generate a braking force so that the vehicle deceleration increases as the vehicle speed increases. Prevention device. 3. The automatic transmission according to claim 1, further comprising an automatic shifting means capable of shifting down by automatic shifting, wherein deceleration by the warning deceleration means shifts down in accordance with vehicle speed in addition to normal automatic shifting control. A vehicle collision prevention device characterized by being combined with deceleration realized by.