JPH0792263A - Obstacle detector on vehicle - Google Patents

Abstract

PURPOSE:To provide an obstacle detector on a vehicle, which judges the distance between an obstacle such as an edge stone or the like and a vehicle body, which informs a driver of the distance and which precisely guides the driver who is bringing the car to the side of the road. CONSTITUTION:Ultrasonic distance sensors 13 are attached to parts near a left front wheel and a left rear wheel, and the radiation direction of an ultrasonic beam is set toward a road surface 14 at the sensors 13 so as to be tilted a little to the outside. The ultrasonic beam is provided with a specified spread angle. A state that reflected waves are received only from the road surface 14 correspondingly to the distance to an edge stone 15, a state that reflected waves are received from the edge stone 15 together with the road surface 14 and a state that reflected waves are received only from the edge stone 15 are set. The time of reflected waves from an object is compared with the time of the reflected waves from the road surface 14 in an ultrasonic distance sensor 13, and the time is judged. Thereby, the distance from the ultrasonic distance sensor 15, i.e., the vehicle body, to the edge stone 15 can be judged in three stages of 'a safe stage', 'a warning stage' and 'a dangerous stage'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention uses an ultrasonic distance sensor to determine the distance to, for example, a curb or a groove approaching the side of the vehicle and notify the driver of the obstacle detection in the vehicle. Regarding the device.

[0002]

2. Description of the Related Art When driving a vehicle, for example, when the vehicle is moved sideways along a curb or a groove or is parked in parallel, the distance between the left front wheel and the curb during forward driving, and the distance between the left rear wheel and the curb during reverse driving Will be the information that the driver wants to know. In particular, during forward driving, even if the angle of the side mirror is changed, the positional relationship between the left front wheel and the curb cannot be confirmed, and therefore problems such as riding on the curb and derailing the groove are likely to occur.

Techniques for measuring the distance to an obstacle such as a curb using ultrasonic waves have long been known. this is,
Emit an ultrasonic signal to the object to be measured,
The distance to the object is measured by measuring the time until the reflected wave from the object returns.

In order to measure the distance to the curb using such an ultrasonic wave, an ultrasonic sensor is attached to a position corresponding to the height of the object of the wheel portion, and the ultrasonic sensor is placed horizontally. It is necessary to radiate ultrasonic waves in the direction to hit the target obstacle and detect the reflected wave from the target at that position. Therefore, in order to accurately measure the distance between the wheel and the curb, it is required to attach the ultrasonic sensor to the tire portion of the wheel.

However, since the wheels are constantly rotating in an actual vehicle, the ultrasonic sensor cannot be attached at this position, and the ultrasonic sensor can be stably fixed at a position close to this. I can't. In this case, it is possible to extend a stay or the like from the body of the vehicle and attach the ultrasonic sensor to the position corresponding to the wheel position at the tip of the stay, but this not only makes the appearance unappealing but also such a position. Then, stones, mud, water, etc., which are bounced up as the vehicle travels, hit the ultrasonic sensor properly, and there are many practical problems.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and radiates ultrasonic waves at a specific angle with respect to the road surface without being particular about the tire position of the wheel or the like. The ultrasonic sensor can be used to accurately measure the distance from the wheel to the curb or groove, and when the curb or groove is approached, the driver will be notified of this. (EN) An obstacle detection device for a vehicle, which is capable of performing a side-by-side approach that is close to a curb or a groove and can be performed easily and reliably.

[0007]

An obstacle detection device for a vehicle according to the present invention is provided with an ultrasonic distance sensor that emits ultrasonic waves obliquely downward and outward on an outer surface of a vehicle body. In the state where the difference between the distance to the road surface set corresponding to the pointing direction of the distance sensor and the measurement distance based on the reflected wave of the ultrasonic wave from the distance sensor is determined to be within a certain error range by the determination means. Obstacles in which the object is determined to be a road surface, and the second determination unit compares the reflected wave of the ultrasonic wave from the distance sensor from the object with the reflected wave from the road surface in time to project or dent from the road surface. In addition to determining the presence of an object, the vehicle based on the state of the overlapping of the reflected wave from the obstacle and the reflected wave from the road surface by the distance determination means, and the change in the time width of the reflected wave from the road surface. Up to the obstacle To determine the near.

Here, the second determining means determines that the falling edge of the reflected wave of the ultrasonic wave from the distance sensor exists ahead of the rising edge of the reflected wave from the road surface, and determines the target. The object is determined to be an obstacle protruding from the road surface, and the rising of the reflected wave of the ultrasonic wave from the distance sensor is determined to be present behind the falling of the reflected wave from the road surface. The object is determined to be an obstacle that is recessed from the road surface.

[0009]

In the vehicle obstacle detection device thus constructed, the ultrasonic distance sensor is attached to the side surface of the vehicle body obliquely toward the road surface, and the reflected wave is detected by the distance sensor. The distance to the object in the directional direction that emits ultrasonic waves is measured. Then, three states, that is, a safe state in which only the road surface is detected, a state of approach caution in which both the road surface and an obstacle are detected, and a danger in which only the obstacle portion is detected are discriminated and detected, depending on the situation of the measurement result. As a result, the driver can be notified of this clearly. Therefore, it is possible to easily and surely perform the width-shifting operation for approaching the curb or the groove.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, as shown in FIG. 1, for example, the front left wheel of the vehicle body 11
Ultrasonic distance sensors 131 and 132 are attached to the side surface portions of the body in the vicinity of 121 and the left rear wheel 122, respectively. From the ultrasonic distance sensors 131 and 132, ultrasonic waves are radiated in the specified direction.
The emitted ultrasonic waves are reflected by the object so that the ultrasonic distance sensors 131 and 132 receive and detect the ultrasonic waves, respectively.

The ultrasonic radiation sensors 131 and 132 mounted on the vehicle body 11 both have their ultrasonic radiation directing directions inclined at a specified angle with respect to the vertical line of the vehicle body and directed away from the vehicle body 11. It should be set toward the road surface 14 of. For example, in the case where the curb 15 exists in the direction of the left side surface of the vehicle body 11, the ultrasonic distance sensors 131 and 132 are provided if a sufficient distance exists between the vehicle body 11 and the curb 15.
The ultrasonic signals emitted from the
Reflected by the sensors 131 and 132,
When the 11 is close enough to the curb 15, the ultrasonic distance sensor
The ultrasonic waves emitted from 131 and 132 strike only the curb 15 and are reflected so that they are detected by the sensors 131 and 132.

That is, as described above, the ultrasonic distance sensor 131
And 132 are set, the distance L between the wheel portion and the curb 15 is to be measured as shown in the figure (B). More specifically, the left front wheel 12 is shown as shown in the figure (A).
The distance Lf between 1 and the curb 15 and the distance Lr between the left rear wheel 122 and the curb 15 are measured.

As shown in FIG. 2, this ultrasonic distance sensor 13
1 and 132 are connected to an electronic control unit (ECU) 20 mounted on this vehicle.
Based on the distance measurement data from each of the ultrasonic distance sensors 131 and 131 at 20, the distance alarm device 21 issues an acoustic or visual alarm, especially when a state of sufficiently close to the curb 15 is detected. To be able to

Here, as shown in FIG. 3, when the wheel is in a range farther than the position A, that is, when the distance between the wheel and the curb 15 is L1 or more, it is recognized as a safe range, and the wheel is curb from the position A. A caution alarm is to be issued until the distance L2 to the curb 15 is approached to 15. Then, when the approach to the curb 15 from the position of B is detected, a danger alarm is issued.

A road surface 14 which is obliquely lateral to the side surface of the vehicle body 11
If the ultrasonic distance sensor 13 (131, 132) is attached to the directional direction and the spread angle of the ultrasonic beam emitted from the distance sensor 13 toward the road surface 14 is used, obstacles existing on the road surface 14 It is possible to measure the distance to an object.

That is, as shown in FIG. 4A, the ultrasonic distance sensor 13 is set at a position apart from the curb 15 on the road surface 14 and at an angle θ with respect to a vertical line from the surface of the road surface 14. Road surface
When the ultrasonic beam is radiated toward 14, if the divergence angle α of the ultrasonic beam emitted from the ultrasonic distance sensor 13 does not reach the curb 15, the reflected wave is (A) in FIG. And as shown in (B), only the reflected wave a from the road surface is obtained. Here, the pulse waveform a1 indicated by the broken line shown corresponding to the reflected wave a in FIG. 5 indicates the time width when the reflected wave a exceeds the specified threshold level.

When such a reflected wave a is received and detected by the ultrasonic distance sensor 13, "v × (t1 / 2)" is calculated by using the time t1 from the oscillation of the ultrasonic wave to the start of reflection.
By calculating (where v is the speed of sound), the distance between the ultrasonic distance sensor 13 and the road surface 14 (direction of the distance sensor 13) can be calculated.

When the ultrasonic distance sensor 13 attached to the vehicle body approaches the curb 13 from such a state, (B) in FIG.
The divergence angle α of the ultrasonic radiation beam is
It will depend on Therefore, in addition to the reflected wave a from the road surface, the reflected wave b from the curb 15 is also detected by the ultrasonic distance sensor 13. That is, as shown in FIGS. 5C and 5D, the reflected wave b from the curb 15 starts to rise before the reflected wave a from the road surface 14 rises. As shown in the figure, when the distance between the sensor 13 and the curb 15 is still large and only a part of the ultrasonic radiation beam hits the curb 15, the reflected wave b
Level is low.

However, as the ultrasonic distance sensor 13 approaches the curb 15, the level of the reflected wave from the curb 15 increases, and the front edge of the reflected wave a from the road surface 14 as shown in FIG. 6A. In this state, the reflected wave b overlaps, and the pulse of this reflected wave also has a wide width in which a and b are combined. Then, the ultrasonic distance sensor 13
When the vehicle approaches the curb 15, the level of the reflected wave b from the curb 13 increases as shown in FIG. 7B, and the reflected wave a from the road surface 14 is separated and a pulse corresponding to the reflected wave a from the road surface is obtained. a1 and the pulse b corresponding to the reflected wave b from the curb 13
1 will be detected independently.

Thus, as the ultrasonic distance sensor 13 is brought closer to the curb 15, the reflected wave b from the curb 15 gradually increases and the reflected wave a from the road surface 14 decreases. Then, as shown in FIG. 4C, when the curb 15 enters the range of the divergence angle α of the radiation beam emitted from the ultrasonic distance sensor 13 and comes out of the range of the road surface 14, As shown in (D), only the reflected wave b from the curb 15 is detected by the ultrasonic distance sensor 13.

Road surface 14 and curb shown in FIGS. 5 and 6
By recognizing and recognizing the reflected wave from 15, the distance relationship between the ultrasonic distance sensor 13 and the curb 15 can be determined. As shown in FIG. 3, only the reflected wave a from the road surface 14 is present. Then, the distance between the ultrasonic distance sensor 13 and the curb 15 is L
It is certified as 1 or more, and the vehicle body to which this sensor 13 is attached is at a position where a sufficient distance is set from the curb 15, and it will be notified that a "safe" distance will be set.
Then, in a state where the reflected wave a from the road surface 14 and the reflected wave b from the curb 15 are simultaneously detected, a "caution" indicating that the vehicle body is approaching the curb 15 is notified, and further from the curb 15. Distance sensor 13 and curb with only reflected wave b
Three-step distance measurement will be performed to notify "danger" when the distance to 15 is L2 or less.

Here, the distance L1 at which the reflection of ultrasonic waves starts to become "road surface + curb", and the distance L2 at which the reflection of only "curb" starts, is the inclination angle of the ultrasonic distance sensor 13 shown in FIG. 4A. θ, the divergence angle α of the beam, the height h of the sensor 13, and the threshold level value when this reflected wave is converted into a pulse waveform.

For example, the larger the inclination angle θ, the earlier the curb 15 is detected, and the discrimination distance L1
And L2 become large. Further, even if the divergence angle α of the beam is increased, the detection of the curb stone 15 is similarly accelerated, and the distance L1
And L2 become large. By the way, in this embodiment, 4
An ultrasonic signal of 0 kHz was used, the tilt angle θ was 15 °, the spread angle α was 20 °, the height h was 50 cm, and the threshold level was 8V. In this case, L1 is 12 cm and L2 is 2 cm in the three-step distance determination. Then, when it is desired to adjust the distances L1 and L2 for the three-step determination,
It suffices to change the parameters θ, α, h, the threshold level, etc. described above.

FIG. 7 is an ECU for detecting such a curb 15.
It shows the flow of processing in step 20.
At 1, the distance to the object is calculated based on the time t from the ultrasonic signal is oscillated by the ultrasonic distance sensor 13 until the reflected wave is received. In step 202, the calculated distance to the object calculated using this reflected wave and the distance to the road surface 14 corresponding to the mounting position (corresponding to the height and the angle θ) of the ultrasonic distance sensor 13 known in advance. The difference between
It is determined whether the difference is within a certain error range ε. The difference between the calculated distance and the distance between the road surface 14 is the error range ε
If it is within the range, it can be judged that the situation is in the situation of (A) and (B) of FIG. 5, and the routine proceeds to step 203, where the judgment flag is set to "road surface".

If it is determined in step 202 that the difference between the calculated distance and the distance between the road surfaces 14 is greater than or equal to the error range ε, it is determined that the reflected wave includes a reflected wave from a portion other than the road surface. In this case, the process proceeds to step 204 and the pulse fall time due to the reflected wave and the normal expected rise time of the reflected wave from the road surface 14 (see FIG. 4).
If it is determined that the fall of the reflected wave is before the planned rise of the reflected wave from the road surface by comparing with (t1) of (A), the process proceeds to step 205.

In step 204, as shown in FIG. 6A, it is judged whether or not the pulse b corresponding to the reflected wave b exists before the pulse a1 due to the reflected wave a from the road surface 14. If the reflected wave b falls before the rise of the pulse corresponding to the reflected wave from the road surface, either the situation of FIG. 6B or the situation of FIG. You can judge that there is.

Therefore, at step 205, it is judged whether or not the pulse b1 of the reflected wave b has risen after the pulse a1 of the reflected wave a from the road surface rises.
If the pulse b1 rises after the pulse a1 rises, it is judged to be the state of FIG. 6C, and the flag "road surface + curb" is set in step 206. If step 205
When it is determined that the pulse b1 does not rise after the pulse a1 rises, it is determined that the pulse b1 of the reflected wave b is thin as shown in (D) of FIG.
In step 207, the flag is set to "curb".

If it is determined in step 204 that the falling edge of the pulse b1 of the reflected wave b is after the rising edge a1 of the reflected wave a from the road surface 14, the pulse b1 in step 208 is determined.
Judges whether the rising edge of 1 is smaller than the set threshold value (pulse width judgment). If it is determined that this pulse width is smaller than the threshold value, it is determined that the situation is (D) in FIG. 6 and the process proceeds to step 207, and the flag is set to "curb". Further, when the pulse width is determined to be equal to or larger than the threshold value, as shown in FIGS. 6A and 6C, the curb 15 and the reflection from the road surface 14 are mixed to form one wide pulse. Therefore, the process proceeds to step 206 and the flag is set to “road surface +
Curb ".

In this way, the ultrasonic distance sensor 13 is attached by radiating ultrasonic waves from the ultrasonic distance sensor 13 in the direction specified by the specified beam width and measuring the reflected wave from the object. How close the car body is to the curb 15 can be determined by measuring the distance in three steps. For example, in step 207, the command for the distance alarm 21 is given with the flag "curb" set. Sounds such as a buzzer and a visual alarm by an indicator light can be appropriately issued.

Here, in the explanation of the operation for determining the distance to approach the obstacle, one ultrasonic distance sensor 13 is used.
I went by, but actually as shown in Figure 1, the left front wheel
It is necessary to set ultrasonic distance sensors 131 and 132 corresponding to the positions of 121 and the left rear wheel 122, respectively, and to warn that the left front wheel 121 and the rear wheel 122 are riding on obstacles such as curbs 15 respectively. Is. Therefore, in each of the ultrasonic distance sensors 131 and 132, if the distance to the curb 15 as described in the embodiment is determined in three stages, the side-by-side operation for the curb 15 can be performed safely and easily. Become.

In the case of the curb 15 formed so as to project above the road surface 14, the distance until the ultrasonic waves emitted from the ultrasonic distance sensor 13 hit the curb 15 is smaller than the distance at which the ultrasonic wave hits the road surface 14. Therefore, the reflected wave from the curb 15 returns to the sensor 13 faster than the reflected wave from the road surface 14. Therefore, by utilizing such a situation, the existence of the curb 15 is recognized and the approach distance to that point is determined as described above.

Further, as an object to which the vehicle is to be moved sideways,
There is a groove that is more recessed than 14. In the case of such a groove, contrary to the curb 15 protruding from the road surface 14, the reflected wave from this groove returns to the sensor 13 part later than the reflected wave from the road surface 14.

As shown in FIG. 8A, an ultrasonic distance sensor
When the position of 13 is sufficiently distant from the groove 16 formed in a state of being recessed from the road surface 14, the groove 16 does not enter the range of the beam spread of the radiated ultrasonic wave from the ultrasonic distance sensor 13, and the road surface 14
Only reflected waves from are detected. Therefore, as shown in FIGS. 9A and 9B, only the reflected wave a from the road surface is detected by the ultrasonic distance sensor 13.

Next, as shown in FIG. 8B, when the vehicle body further approaches the groove 16 and the distance between the ultrasonic distance sensor 13 and the groove is L1, the ultrasonic distance sensor 13
The beam width of the ultrasonic wave radiated from the vehicle covers the range of the groove 16 together with the road surface 14, and as shown in FIGS. 9C and 9D, and 10A and 10B of FIG. The reflected wave c from the groove is detected behind the reflected wave a.

Then, the vehicle approaches the groove 16 further, and FIG.
As shown in (C) of FIG. 10, when only the groove 16 portion enters the range of the spread of the ultrasonic beam emitted from the ultrasonic distance sensor 13, as shown in (C) and (D) of FIG. As the level of the reflected wave a from the road surface 14 gradually decreases and the pulse width of the reflected wave c from the groove 16 increases, the ultrasonic distance sensor 13, that is, the wheel is sufficiently close to the groove 16. You will be able to recognize that you have entered the "danger" area.

That is, even when the obstacle is a groove, three-step distance determination is performed, that is, a state where the wheel is within the safety range from the groove, a state where the wheel is within the caution range, and a state where the wheel is within the danger range. When it is determined to be within the caution range, an appropriate alarm is issued.

In the above-described embodiments, the ultrasonic distance sensor is attached to the side surface of the vehicle body 11, particularly to the positions corresponding to the left front wheel and the left rear wheel. However, this distance sensor may be attached not only to the left side of the vehicle body but also to the right side thereof. Further, as shown in FIG.
The ultrasonic distance sensor 13 may be attached to the rear bumper 111. In this case, the directivity direction of the distance sensor 13 for radiating ultrasonic waves is set toward the road surface behind the vehicle body 11.

That is, in a parking lot where tires are stopped by curbs 15, the approach distance to the curb 15 can be discriminated when the vehicle is parked by driving in the back direction. Can be clearly determined.

[0039]

As described above, according to the obstacle detecting device for a vehicle according to the present invention, the approach distance to an obstacle such as a curbstone or a groove is divided into three levels of "safety", "caution" and "danger". It is determined, and for example, the guideline information of the distance to the driver and the distance to the curb or groove during parallel parking can be clearly obtained, and the driving operation can be performed with peace of mind especially when parking. .

[Brief description of drawings]

FIG. 1A is a plan view of a vehicle body for explaining the outline of an obstacle detection device for a vehicle according to an embodiment of the present invention, and FIG.

FIG. 2 is a configuration diagram illustrating an obstacle detection device used in this embodiment.

FIG. 3 is a diagram illustrating an obstacle to a vehicle.

FIG. 4A to FIG. 4C are views for explaining a curb detection condition by an ultrasonic distance sensor in a state where a curb is sequentially approached.

FIG. 5A to FIG. 5D are diagrams for sequentially explaining conditions of detected reflected waves in the distance sensor in the process of approaching the curb.

6A to 6D are diagrams sequentially illustrating the states of reflected waves following FIG.

FIG. 7 is a flowchart illustrating a flow of processing for determining a distance of a vehicle body with respect to a curbstone.

FIG. 8 illustrates a second embodiment of the present invention.
(A)-(C) is a figure which respectively explains a groove detection situation by an ultrasonic distance sensor one by one.

FIG. 9A to FIG. 9D are diagrams for sequentially explaining the situation of the reflected waves detected by the distance sensor in the process of approaching the groove.

10 (A) to (D) are diagrams for sequentially explaining the situation of reflected waves following FIG. 9.

FIG. 11 is a diagram for explaining the third embodiment of the present invention.

[Explanation of symbols] 11 ... Vehicle body, 121, 122 ... Left and right wheels, 13, 131, 132 ... Ultrasonic distance sensor, 14 ... Road surface, 15 ... Curb, 16 ... Groove, 20 ... Electronic control unit, 21 ... Distance alarm apparatus.

Claims (3)

[Claims] 1. A rise time of a reflected wave of the radiated ultrasonic wave, which is set so as to radiate the ultrasonic wave obliquely downward and outward to the outer surface of the vehicle body, and the distance to the object in the pointing direction. Based on the ultrasonic distance sensor, the difference between the distance to the road surface set corresponding to the direction of the distance sensor and the measurement distance based on the reflected wave of the ultrasonic wave from the distance sensor is constant. First determining means for determining the object as a road surface in a state of being determined as an error range, a reflected wave from the object of ultrasonic waves from the distance sensor, and a reflected wave from the road surface in time. Second comparing means for comparing and comparing the existence of an obstacle protruding or dented from the road surface, a state of overlap between a reflected wave from the obstacle and a reflected wave from the road surface, and a reflected wave from the road surface Based on the change of the time width of An obstacle detection device for a vehicle, comprising: a distance determination unit that determines whether the vehicle approaches the obstacle. 2. The second determining means determines that the falling edge of the reflected wave of the ultrasonic wave from the distance sensor exists ahead of the rising edge of the reflected wave from the road surface, and determines the target. The obstacle detection device for a vehicle according to claim 1, wherein the obstacle is determined as an obstacle protruding from the road surface. 3. The second determining means determines that the rising edge of the reflected wave of the ultrasonic wave from the distance sensor is behind the falling edge of the reflected wave from the road surface, and determines the target. The obstacle detection device for a vehicle according to claim 1, wherein the obstacle detection device determines that the obstacle is an obstacle recessed from a road surface.