JPH0431074B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a collision prediction device mounted on a vehicle, and particularly to a collision prediction device suitable for combination with an occupant protection device such as an air bag.

Conventional technology Conventionally, vehicles are equipped with distance detection sensors, relative speed detection sensors, etc., to detect the distance and relative speed between the vehicle and an obstacle approaching from the front of the vehicle.
Collision prevention that determines whether the vehicle will collide with an obstacle based on the relative speed when the vehicle and the obstacle approach a certain distance, and operates the brake lever etc. according to the result. A device has been devised.

For example, this type of device has already been proposed in Japanese Patent Publication No. 39-5668.

The principle of such a conventional device and its problems will be explained with reference to FIG. In FIG. 9, 1 is a car equipped with a conventional collision prevention device (not shown), and a sensor beam 2 is emitted forward from the car 1 to measure the distance and relative speed to obstacles. ing. The collision prevention device uses the sensor beam 2 to calculate the presence or absence of an obstacle in front of the vehicle 1, the distance to the obstacle, and the relative speed between the obstacle and the vehicle 1.

That is, the collision prevention device mounted on the vehicle 1 emits a sensor beam 2 in front of the vehicle 1, and measures the time it takes for the sensor beam 2 to be reflected by an obstacle such as an oncoming vehicle and for the reflected beam to be received. By doing so, the distance between the vehicle 1 and the obstacle is calculated.
In addition, a first reference distance l ₁ and a second reference distance l ₂ shorter than the first reference distance are predetermined, and the obstacle is detected at the first reference distance l ₁ . Based on the time difference between the signal and the detection signal detected at the second reference distance _l2 , the speed at which the obstacle approaches the vehicle 1, that is, the relative speed between the vehicle 1 and the obstacle is calculated.

Based on the results, when the distance between the vehicle 1 and the obstacle reaches the second reference distance _l2 ,
If the relative speed between Car 1 and the obstacle exceeds a predetermined speed, it is determined that there is a risk of collision, and the brake system of Car 1 is activated, or safety devices such as airbags are activated. .

By the way, such conventional collision prevention devices are
There is no problem when driving in a straight line, but when the road curves or when turning right at an intersection, a certain angular difference occurs between the axis of the sensor beam 2 and the direction of travel of the vehicle 1. Multiple objects (cars, guardrails, etc.) would cross the vehicle, and depending on the timing and position of the crossing, the collision prevention system could malfunction.

A detailed explanation will be given with reference to FIG. 9. 9th
In the figure, 3 and 4 are oncoming vehicles normally traveling in the opposite lane, 5 is a guardrail on the opposite lane side, and 6 is a median strip. A vehicle 1 equipped with a collision prevention device that is normally traveling on a curved section emits a sensor beam 2 in front of it. The light is irradiated in a direction that is deviated by a certain angle θ with respect to the traveling direction A. Therefore, the oncoming vehicles 3 and 4 that are normally traveling in the oncoming lane will cross the sensor beam 2. In this case, the oncoming vehicle 3 reaches the first reference distance point at a certain time _t1 .
Suppose that the oncoming vehicle 4 crosses _the second reference distance point _l2 at time _t2 . At that time, if the time t ₁ - _{t 2} is shorter than the predetermined time, the collision prevention device will erroneously determine that an obstacle is approaching on the axis of the sensor beam 2 at a speed higher than a certain speed, and will apply sudden braking. This may cause the vehicle to explode or activate airbags, etc.

The same phenomenon occurs between guardrail 5 and oncoming vehicle 3.
Alternatively, it may occur between the oncoming vehicle 4 or between the oncoming vehicle or the oncoming vehicle 4 and the median strip 6, which may cause the collision prevention device to malfunction.

Therefore, in recent years, various devices have been proposed as collision prevention devices that take measures to prevent such malfunctions. For example, there are the inventions described in Japanese Patent Publication No. 55-45412 and the invention described in Japanese Patent Application Laid-Open No. 58-81840.

Problems to be Solved by the Invention This invention is applicable to cases where the vehicle is not traveling straight, such as at a curved section of the road or at an intersection, that is, when the direction of travel of the vehicle and the sensor beam output direction of the obstacle detection sensor are misaligned. The goal is to prevent the equipment from malfunctioning even in the event of a malfunction. That is, an object of the present invention is to provide a collision prediction device that has a configuration different from that of the conventional device disclosed in the above-mentioned publication and is designed to prevent malfunctions.

Means for Solving the Problems The present invention includes: signal wave emitting means for emitting ultrasonic waves or electromagnetic waves to a predetermined outside of a vehicle; reflected wave detecting means for detecting reflected waves of the emitted ultrasonic waves or electromagnetic waves; a distance detecting means for detecting the distance between the obstacle and the vehicle based on at least the output of the reflected wave detecting means; a first determining means for determining that the distance detecting means has detected a predetermined first reference distance; A timer starts measuring time in response to the output of the first determining means, and when the timer measures a predetermined time, the distance detected by the distance detector is compared with a second predetermined reference distance. , distance comparison means for deriving an output when the distance detected by the distance detection means is less than or equal to a second reference distance; and one or more obstacle detection points at a distance other than the first reference distance and the second reference distance. and a third discriminating means for discriminating that an obstacle has passed over the obstacle detection point based on the output of the distance detecting means, and an output of the distance comparing means, and an output of the third discriminating means. The configuration further includes a predictive output deriving means for deriving a predictive output of a collision between the vehicle and an obstacle.

The distance detecting means determines the distance between the vehicle and the obstacle based on the time from when the ultrasonic wave or electromagnetic wave is emitted from the signal wave emitting means until the reflected wave of the ultrasonic wave or electromagnetic wave is detected by the reflected wave detecting means. It can be a device for detecting.

The distance detecting means also performs triangulation on the angle of the reflected wave detected by the reflected wave detecting means, particularly the angle between the obstacle or electromagnetic wave emitted from the signal wave emitting means and the reflected wave detected by the reflected wave detecting means. By applying the law, it can also be used as a device for determining the distance between a vehicle and an obstacle.

Function Next, the function of the present invention will be explained with reference to FIG. An obstacle detection sensor provided in the vehicle 1 emits ultrasonic waves or electromagnetic waves as a sensor beam 2, and the distance to an obstacle that reflects the sensor beam 2 is measured. The first discrimination means derives a discrimination output when the obstacle reaches a first reference distance l ₁ on the sensor beam 2. Similarly, the second discrimination means detects the second discriminator on the sensor beam 2.
When the obstacle reaches the reference distance l ₂ of , the discrimination output is derived. Further, the passage detecting means is configured to detect a plurality of obstacle detection points l _A , for example eight, at equal intervals between the first reference distance l ₁ and the second reference distance l ₂ in advance.
_lB ... _lH are set, and when an obstacle passes through each detection point _lA to _lH , the output is derived. Also,
In response to the output of the second determining means, the obstacle
The relative speed between the vehicle 1 and the obstacle when the reference distance is reached is detected. This detection can be calculated based on the time difference between the force of the first discrimination means and the output of the second discrimination means. The collision prediction device output means outputs a collision prediction signal only when the relative speed is equal to or higher than a predetermined speed and there is an output from the passage detection means. Therefore, the first
Even if the oncoming vehicles 3 and 4 accidentally cross the reference distance l ₁ and the second reference distance l ₂ , it is possible that the obstacle has passed through all of the obstacle detection points l _A to l _H. Unless detected, the predictive signal output means will not produce an output and will not malfunction.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Vehicles in which this device is installed are generally automobiles such as regular cars and freight cars, but it can also be installed in vehicles such as trains and trains.

Further, the location where this device is mounted is preferably at the front end or rear end of the vehicle. This is because there are many collisions and rear-end collisions to the front of the vehicle or from the rear of the vehicle.

Embodiment 1 FIG. 1 is a block diagram of a first embodiment of the present invention. In the figure, 7 is a light emitting element as a signal wave emitting means. The light emitted from the light emitting element 7 is focused by the light output lens 8 and is emitted as a sensor beam 2 in front of the automobile 1. For this reason, it is preferable to use light of a specific wavelength so that the light emitted by the light emitting element 7 can be easily distinguished from other light existing in the space. That is, the light emitting element 7 may be a high output light emitting diode or the like, but more preferably a semiconductor laser or the like that emits coherent light may be used.

Note that it is convenient for detection to use infrared or near-infrared light.

If an obstacle 9 exists in front of the vehicle 1, the sensor beam 2 emitted from the light emitting element 7 is reflected by the surface of the obstacle 9. Light receiving elements 10 and 1
1 is for detecting this reflected wave 2R. The light receiving element 10 is a light emitting lens 8 of the light emitting element 7.
On the other hand, the sensor beam 2 emitted from the light output lens 8 is configured to receive a reflected wave 2R that is captured and focused by the light input lens 16 located at a distance L1 in a direction perpendicular to the sensor beam 2. Therefore, a triangle is formed by connecting the outgoing lens 8 from which the sensor beam 2 is emitted, the incoming lens 16 which receives the reflected wave 2R, and the reflection point of the obstacle 9 which reflects the sensor beam 2, and the reflected wave 2R A well-known triangular distance method can be used to determine the distance from the difference in the incident angle of .

For this purpose, in this embodiment, the light receiving element 10 includes a plurality of light receiving pieces 101, 10b,
10d, 105, and 10h, and depending on which light receiving piece receives the reflected wave 2R,
The distance to the obstacle 9 is determined.

In the figure, a light entrance lens 17 and a light receiving element 11 provided on the right side of the light emitting element 7 have a similar configuration. On this side, the distance between the light input lens 17 into which the reflected wave 2R enters and the light output lens 8 which outputs the sensor beam 2 is set to L2 (L2≠L1). The light receiving element 11 is the light receiving element 10.
Almost similarly, the plurality of light receiving pieces 11a, 11c, 1
It consists of 1e, 11g and 112.

The reason why the light input lenses 16 and 17 and the light receiving elements 10 and 11 are arranged at different distances on both sides of the light emitting element 7 and the light output lens 8 is as follows. That is, when the distance L1 between the light output lens 8 and the light input lens 16 is short, the reflected wave 2R reflected from the obstacle ₉ at a distance l 1 from the vehicle 1, the reflected wave reflected from the vehicle 1 at a distance _lA , and The angular difference between the two is very small, and if the reflected waves are to be received by different light-receiving pieces, the resolution of the light-receiving pieces must be increased to provide high quality and high precision, which tends to result in expensive equipment. Therefore, in this embodiment, two light-receiving elements 10 and 11 are used, and the distance detected by each light-receiving element 10 and 11 is alternately changed to increase the difference in detected distance, thereby increasing the resolution of the light-receiving piece. It has been devised to enable accurate detection without increasing the

The signals received by the light receiving elements 10 and 11 are
It is provided to the CPU 19 via the A/D converter 22A and the I/O interface 18.
The A/D converter 22A is for converting analog signals from the light receiving elements 10 and 11 into digital signals suitable for the CPU 19. Also, in the I/O interface 18, the signal
Converted to a level suitable for CPU19. CPU1
9 has a ROM that stores programs for control operations and can write and read prescribed data.
RAM21 is connected.

Furthermore, a safety device 22 is coupled to the CPU 19 via the I/O interface 18. This safety device 22 is, for example, an air bag, and is used to connect the CPU 19 to the I/O interface 1.
8.

FIG. 3 is an illustrative diagram showing a memory map of the RAM 21 of the embodiment shown in FIG. RAM21
is area 211 for timer and flag F _A
It includes areas 212 to 220 for ~F _H and F ₂ and a work area 221 for temporarily storing arbitrary data. The timer area 211 is
This is an area where the passage of time is written. Each of the flag areas 212 to 220 is provided corresponding to each light receiving piece of the light receiving elements 10 and 11 shown in FIG. The corresponding flag area is set.

FIG. 4 is a flow diagram for explaining the operation of the embodiment shown in FIG.

Next, the operation of this embodiment will be explained with reference to FIGS. 1, 3, and 4.

When the control operation starts, the CPU 19 initializes and clears the memory contents of the RAM 21 (step S1). Next, the CPU 19 operates the light emitting element 7 to output the detected wave output, that is, the sensor beam 2 (step S2). Then, it is determined whether the measured value of the timer 211 has reached a predetermined reference value _T0 (step S3). In this case, since the timer 211 has not yet been activated, the process proceeds to step S4, where it is determined whether or not the light receiving piece 101 of the light receiving element 10 has received light. If the distance between the vehicle 1 and the obstacle 9 is still long and the obstacle 9 has not reached the first reference distance _l1 in front of the vehicle 1, the light receiving piece 101 and other light receiving pieces receive the reflected wave 2R. The operation from step S2 is repeated through step S7, step S9, step S11, step S13, and step S6.

In step S4, the light receiving piece 101 receives the reflected wave, and when the CPU 11 determines this, the timer 211 is set (step S5). Since the detection is not finished yet (step S6),
The same detection operation from step S2 is repeated. As the obstacle 9 approaches, it approaches the predetermined detection points l _A , l _B , ... l _H and the second reference distance l ₂ in order, so that each of these detection points and When the obstacle reaches the second reference distance l ₂ , the reflected wave reflected by the obstacle 9 is detected by the corresponding light receiving piece, and the obstacle is detected. Then, corresponding flags F _A to F _H and F ₂ are set in each of these cases.

On the other hand, in parallel with the above-described obstacle detection determination and flag setting control, a determination is always made in step S3 as to whether or not the value of the timer 211 has reached a predetermined reference time _T0 . When the timer 211 reaches the reference time _T0 , the control operation proceeds from step S to S15. Then, in step S15, it is determined whether the flag _F2 is set. That is, the timer 211 is set when the obstacle 9 reaches the first reference distance _l1 from the car 1, and the obstacle 9 reaches the second reference distance _l1 between then and the predetermined reference time T0. It is determined whether or not it has reached ₂ . Then, if the obstacle 9 that has reached the first reference distance _l1 does not reach the second reference distance _l2 within the predetermined time _T0 ,
Since the relative speed between the vehicle 1 and the obstacle 9 is low, it is determined that a collision will not occur, the timer 211 and each flag are reset, and the control operation is repeated from the beginning.

In step S15, the CPU 19 sets the flag.
When F ₂ is determined to be set, the flag F _A is further set.
It is determined whether all of _-FH are set (step S16). That is, the obstacle detection point l _A
It is determined whether the obstacle 9 has passed through all the points of ~ _lH . As a result, for example, after the obstacle 9 has been identified at the first reference distance l ₁ , a bird or the like that accidentally crosses the point in front of the car 1 at the second reference distance l ₂ or a bird that has already crossed the point on a curve can be detected. As explained above, an oncoming vehicle traveling in the opposite lane may cross the road, and even if flag _F2 is set by chance in such a case, the safety device will not be erroneously activated.

If flag F ₂ and all flags F _A to F _H are set, the relative speed between the vehicle 1 and the obstacle 9 is greater than the safe speed, and the real obstacle 9 is approaching. It is determined, the safety device 22 is activated, and the control operation is completed.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to FIGS. 5 to 7.

FIG. 5 is a block diagram of a second embodiment of the present invention. This embodiment is configured to use ultrasonic waves as signal waves for detecting obstacles.
For this purpose, the ultrasonic oscillator 23 transmits the ultrasonic waves oscillated from the ultrasonic oscillator 23 to the sensor beam 2.
A wave transmitting device 24 for emitting the sensor beam 2 as It is provided. The ultrasonic oscillator 23 is connected to the I/O from the CPU 19.
It operates based on signals provided via the O interface 18. Further, the output of the amplification detection device 26 is transmitted via the I/O interface 18.
It is given to CPU19. In this embodiment, the control device that controls the ultrasonic oscillator 23 and performs control operations based on the output of the amplification and detection device 26 is composed of a so-called microcomputer, and its configuration is shown in FIG. It is the same as that shown, and the same parts are given the same numbers and the explanation here will be omitted.

FIG. 6 is an illustrative diagram showing a memory map of the RAM 21 shown in FIG. Area 222 is an area for a timer, and a predetermined elapsed time is stored. Area 223 stores the first reference distance l ₁ . Area 224 stores the second reference distance l ₂ . Areas 225 to 232 are areas for flags F _A to _{F H.} Areas 233-240 are
These are areas for storing the distances from the vehicle to the respective predetermined obstacle detection points _lA to _lH .

FIG. 7 is a flow diagram for explaining the operation of the embodiment shown in FIG. Next, the operation of this embodiment will be explained with reference to FIGS. 5 to 7.

When the control operation starts, the CPU 19 initializes and clears the timer area 222 and flag areas 225 to 232 of the RAM 21 (step S21). Next, the ultrasonic oscillator 23
A signal is applied to the ultrasonic wave, an ultrasonic detection wave is outputted (step S22), and the reflected wave is waited for to be received (step S23). Then, the distance l _S to the obstacle is calculated based on the time from when the ultrasonic wave is emitted until the reflected wave is received (step S2).
4).

Next, the timer 222 sets a predetermined reference time T ₀
It is determined whether or not the
A). At this time, the timer has not yet been set and is not operating, so step S25 is performed.
Proceed to. In step S25, the distance l _S to the obstacle 9 calculated in step S24 is compared with the first reference distance l ₁ stored in the area 223 of the RAM 21. If the distance between the vehicle 1 and the obstacle 9 is large and l _S >l ₁ , then step S28,
After going through S29 and S32, it is determined in step S27 whether or not the detection control has ended, and if it has not ended, the operations from step S22 are repeated.

In step S25, when the calculated distance l _S to the obstacle reaches the first reference distance l ₁ , the timer 222 is set and the detection operation from step S22 is repeated. Then, step S28
Then, the distance L _S to the obstacle is compared with the detection point _A , and if they match, a flag F _A is set (steps S28 and S29). Similarly, step S
30 and S31, the calculated distance l _S and up to the detection point l _B are compared, and if they match, a flag is set.
Set F _B. This control is repeated in the same way.

On the other hand, the CPU 19 determines whether the above-mentioned calculated distance _lS matches the detection points _lA to _lH , and at the same time, in step S25A, the timer 222 sets the reference time.
It is determined whether or not T ₀ has been reached. Then, in step S25A, when the measured value of the timer 222 reaches the reference time _T0 , the process advances from step S25 to S34. Here, the distance l _S to the obstacle 9 calculated at that time and the area 2
The distance is compared with the second reference distance _l2 stored in 24. If the calculated distance l _S is larger than the second reference distance l ₂ , it is determined that the relative speed between the vehicle 1 and the obstacle 9 is within the safe range below the collision speed, and the timer area 222 and flag area 22
5 to 232 are cleared (step S21), and the control operation is repeated from the beginning.

In step S34, if it is determined that the calculated distance _lS is equal to or less than the second reference distance _l2 , that is, the distance between the vehicle 1 and the obstacle 9 is closer than the second reference distance _l2 . If it is determined that the speed is higher than the safe speed, then it is determined whether or not all flags F _A to F _H are set. That is, similarly to the first embodiment, the obstacle 9 approaches from the first reference distance l ₁ to the second reference distance l ₂ sequentially, and it is determined whether or not it has passed through all the detection points. do. Since the CPU 19 makes such a determination,
Consideration has been taken to prevent the safety device 22 from malfunctioning due to an erroneous judgment.

At the reference time _T0 , if the calculated distance _lS is smaller than the second reference distance _l2 and all flags F _A to F _H are set, the safety device 22 is activated (step S36) and a collision is prevented. or the occupants of the automobile 1 are protected.

FIG. 8 shows a modification that can be applied to both the first and second embodiments of the invention. FIG. 8 shows a case where three combinations of the first reference distance, the second reference distance, and the detection point, k, l, and m, are provided. In this case, depending on the vehicle speed of the vehicle 1, for example, if the vehicle speed of the vehicle 1 is relatively fast, the long distance is k, if it is slow, the short distance is m, and if the speed is intermediate, the intermediate distance is l. If a collision prediction signal is generated for each,
The device can be designed in consideration of the operating time of the safety device 11 such as an airbag, and delays in the operation of the safety device 11 can be prevented.

In each of the embodiments described above, the safety device 11 such as an air bag is operated based on the collision prediction signal, but instead of this, an alarm sound or an alarm display is made in response to the collision prediction signal. It's okay. Further, a configuration may be adopted in which the brakes are automatically applied in response to a collision prediction signal.

Effects of the Invention As described above, according to the present invention, it is possible to provide a collision prediction device that can reliably detect obstacles approaching a vehicle, does not cause false detection, and outputs accurate collision prediction signals.

In particular, it is possible to provide a device that accurately detects obstacles without erroneous detection even when the traveling direction of the vehicle and the detection direction of the obstacle detection sensor are deviated from each other in curved sections of roads, intersections, etc.

Furthermore, if a device is used that measures the distance to an obstacle using a so-called triangulation method, accurate measurement can be performed with an inexpensive device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention. FIG. 2 is an illustrative diagram for explaining the principle and operation of the present invention. Figure 3 shows
FIG. 2 is an illustrative diagram showing a memory map of a RAM according to a first embodiment of the present invention. Figure 4 shows the first example of this invention.
FIG. 3 is a flow diagram for explaining the operation of the embodiment. FIG. 5 is a block diagram of a second embodiment of the present invention. FIG. 6 is an illustrative diagram showing a memory map of the RAM according to the second embodiment of the present invention. FIG. 7 is a flow diagram for explaining the operation of the second embodiment of the present invention. FIG. 8 is a diagram showing a further application example of the present invention. Figure 9 shows
FIG. 2 is an illustrative diagram for explaining the operation of a conventional device. In the figure, 1 is a car, 2 is a sensor beam,
2R is a reflected beam, 7 is a light emitting element, 9 is an obstacle,
10 and 11 are light receiving elements, 19 is a CPU, and 21 is a
RAM, 22 is a safety device, l ₁ is the first reference distance, l ₂
is the second reference distance, and l _A to l _H are obstacle detection points, respectively.

Claims (1)

[Scope of Claims] 1. A device that detects the approach of obstacles around a vehicle and predicts a collision between the vehicle and the obstacle, comprising a signal wave that emits ultrasonic waves or electromagnetic waves to a predetermined direction outside the vehicle. emitting means; reflected wave detecting means for detecting reflected waves of the emitted ultrasonic waves or electromagnetic waves; distance detecting means for detecting the distance between the obstacle and the vehicle based on at least the output of the reflected wave detecting means; a first determining means for determining that a first reference distance predetermined by the distance detecting means has been detected; a time measuring means for starting time measurement in response to the output of the first determining means; When measuring time, the distance detected by the distance detection means is compared with a predetermined second reference distance, and an output is derived when the distance detected by the distance detection means is less than or equal to the second reference distance. distance comparison means, setting one or more obstacle detection points at distances other than the first reference distance and the second reference distance, and detecting obstacles on the obstacle detection points based on the output of the distance detection means; a third discriminating means for discriminating that the vehicle has passed, and a prediction for deriving a collision prediction output between the vehicle and the obstacle when there is an output from the distance comparing means and an output from the third discriminating means. A collision prediction device including an output deriving means. 2. The collision prediction device according to claim 1, wherein the detection point is set between the first reference distance and the second reference distance. 3. The distance detecting means determines the distance between the obstacle and the vehicle by measuring the time from when the signal wave emitting means emits ultrasonic waves or electromagnetic waves until the reflection detecting means detects the reflected waves. A collision prediction device according to claim 1 or 2, which detects distance. 4. The reflected wave detection means includes a plurality of detection elements whose positions are shifted from each other, and the distance detection means determines which detection element of the reflected wave detection means detects the reflected wave according to a triangulation method. The collision prediction device according to claim 1 or 2, which detects the distance between the obstacle and the vehicle depending on whether the obstacle is detected. 5. Claim 2, wherein the obstacle detection points include a plurality of points set at equal intervals.
The collision prediction device according to item 1, 3 or 4. 6. Claim 1, wherein the collision prediction device further comprises a vehicle occupant protection device such as an airbag that operates in response to the output of the prediction output deriving means.
The collision prediction device according to any one of items 1 to 5.