JPH06305383A - Obstruction detecting device - Google Patents

Abstract

PURPOSE:To detect an obstruction even at a curved road and the like by computing a displacement quantity for moving a light projecting lens in either of the right and left directions based on an output signal from a steering angle sensor, and feeding a control signal corresponding to the computed displacement quantity to a driving means. CONSTITUTION:A rotation angle and a rotation direction thereof due to steering of a steering wheel are detected by a steering angle sensor to output a signal. Based on the output, relationship between displacement quantities of both light projecting lens 14, 15 and the rotation angle and the rotation direction of the steering wheel is computed by a displacement quantity computing circuit 33. Upon receipt of a displacement quantity signal from the displacement quantity computing circuit 33, a driving circuit 22 comprising a distance detecting part controls drive of a linear motor in proportion to the magnitude of the signal. This linear motor moves laser beams in either of right and left directions by the proportional quantity. With this constitution, the laser beam receiving direction is followed even at a sharply curved road so as to ensure collision warning.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an obstacle detecting device used for detecting a front target such as an obstacle in front of a vehicle to prevent a collision accident from occurring.

[0002]

2. Description of the Related Art As a conventional obstacle detection device such as a vehicle collision warning device, there is one shown in FIG. 6, for example. In the figure, 1 is a laser beam (light beam) emitted from a laser diode (hereinafter, LD),
A distance detection unit that detects the distance between the own vehicle and the obstacle, and 2 is a running state detection unit that detects the running state of the own vehicle such as the speed of the own vehicle.

Reference numeral 3 designates the own vehicle based on the distance information sent back to the distance detection unit 1 in response to the distance detection command and the own vehicle speed information detected by the traveling state detection unit 2. ,
It calculates the relative speed with the obstacle such as the vehicle in front and judges whether the obstacle is a stationary object or a moving object, and also the individual vehicle speed, relative speed, and the free running time until the driver brakes. It is a signal processing unit that determines the possibility of collision between the host vehicle and an obstacle according to the distance setting or the like set according to the difference.

4 is based on the information from the signal processing unit 3,
This is an alarm notification unit that displays the distance between the host vehicle and the obstacle and issues an alarm when the signal processing unit 3 determines that there is a possibility of collision with the obstacle.

Next, the operation will be described. The traveling state detection unit 2 includes a vehicle speed sensor 31, and the signal processing unit 3 includes an arithmetic circuit 41 and a distance setting switch 42. Vehicle speed sensor 3
The vehicle speed signal of the host vehicle detected in 1 is sent to the arithmetic circuit 41. When the vehicle speed calculated based on the vehicle speed signal is 35 Km / h or more, the arithmetic circuit 41 sends the distance detection command signal to the distance detection unit 1. Is sent.

In the distance detecting section 1, a signal corresponding to the distance detection command signal is sent from the arithmetic circuit 41 to the drive signal generating circuit 11
The drive signal generating circuit 11 receives the LD shown in FIG.
The light emission signal is sent to the LD switching driver 12. The LD switching driver 12 sends out the signals shown in FIGS. 7B, 7C and 7D based on the received LD light emission signal (a).
LD-L, LD- of the LD array 13 as a light emitting means
C and LD-R are made to always emit light with the same intensity.

The laser beam from the LD-L of the LD array 13 is directed to the front left of the vehicle, the laser beam from the LD-C is directed to the front, and the laser beam from the LD-R is directed to the front right by the light projecting lens 14. Is emitted through LD-
The laser beam of C is used to detect an obstacle ahead, the laser beam of LD-L is used to detect an interrupting vehicle from the left lane, and the laser beam of LD-R is used to detect an interrupting vehicle from the right lane.

The reflected light from the obstacle is condensed by the light receiving lens 15 and is received by the photodiode (hereinafter referred to as PD) 16. This received light signal is sent to the amplifier circuit 17, which amplifies it and outputs the signal of FIG. In this signal, a reflection signal B from an obstacle and a reflection signal A from a short distance road surface are mixed.

The threshold generation circuit 18 is based on the LD light emission signal (a) output from the drive signal generation circuit 11 and is shown in FIG.
The threshold signal shown in FIG.
Output to. The comparator 19 compares the level of the output signal (e) of the amplifier circuit 17 with this threshold value signal (f) to extract only the reflected signal from the obstacle, and the obstacle shown in FIG. Outputs the object detection pulse signal.

The counter 20 has an L level as shown in FIG.
At the rising edge of the D emission signal (a), the reference pulse generation circuit 21
Starts counting the clock pulse signal supplied from, stops counting at the rising edge of the obstacle detection pulse signal (g) based on the reflection signal from the obstacle, and counts from the count-up time and the speed of light to the obstacle. Seeking distance information,
It is sent to the arithmetic circuit 41 of the signal processing unit 3.

Next, a method of determining the possibility of collision in the arithmetic circuit 41 of the signal processing unit 3 will be described with reference to the flowchart shown in FIG.

First, when the power is turned on, the process proceeds to the START step, and the CPU, RAM, etc. constituting the arithmetic circuit 41 are initialized. Next, in step 11, a pulse having a predetermined pulse width is output to the drive signal generating circuit 11 in a predetermined cycle, and in the next step ST12, the distance from the counter 20 of the distance detecting unit 1 to the obstacle is measured every predetermined cycle. The distance signal indicating the information of R and the vehicle speed signal indicating the information of the own vehicle speed V _f from the vehicle speed sensor 31 of the traveling state detecting unit 2 are taken into the arithmetic circuit 41.

Then, in step ST13, the distance signal R is converted into a display signal and sent to the distance display 51 for display.
Next, in step ST14, the inter-vehicle distance R is differentiated to determine the relative speed (d / dt) R between the obstacle such as the preceding vehicle and the host vehicle.
Is calculated using a calculation method such as the least squares method, and the vehicle speed V _{a of the} preceding vehicle is relative to the own vehicle speed V _f (d / dt).
It is calculated by the sum with R.

In this calculation, (d / dt) R <0
In the case of (d / dt) R> 0, the distance is decreasing, and the distance is decreasing, and (d / dt) R = 0. In the case of, it shows that there is no change in the distance.

In determining the possibility of collision with an obstacle, the initial speed of the vehicle is V _f (m / s) and the initial speed of the obstacle (preceding vehicle) is V _a (m / s). Deceleration performance is α (m /
s ² ), the difference between the stop distance V _f ² / 2α of the host vehicle and the stop distance V _a ² / 2α of the preceding vehicle is set to the time T until the host vehicle sets the brake by the distance setting switch 42. _The distance R shown in the equation 1, which is the _sum of the free running distance V _f · T _{d due} to _d , becomes the reference for collision judgment.

[0016]

[Equation 1]

Therefore, first, in step ST15, the relative speed (d / dt) R is compared with the vehicle speed V _f , and-(d /
dt) In the case of R≈V _f , that is, when the obstacle is regarded as a road stop, the process proceeds to step ST16, and since V _a = 0 in Formula 1, the collision law is calculated by the following formula 2 Determine the risk.

[0018]

[Equation 2]

When the equation 2 is satisfied, there is a risk of collision with an obstacle, and the process proceeds to step ST19 to generate an alarm signal and send it to the alarm notifying unit 4, and the alarm device 52 causes the danger. A warning for avoidance is issued.

On the other hand, as a result of the judgment in step ST15,
When − (d / dt) R≈V _f is not satisfied, the obstacle is a preceding vehicle traveling on the road ahead, and the danger judgment should be originally made according to Equation 1. However, the relative velocity (d /
Since the calculation error of dt) R may not be strict, the calculation error may give an erroneous alarm. Therefore, in the case of a preceding vehicle with an obstacle moving, the relative speed (d / d) is calculated in step ST17.
t) First, it is determined whether R is equal to or higher than a predetermined speed C (m / sec).

As a result, when (d / dt) R ≧ C, the relative speed is high and the vehicle is approaching rapidly. Therefore, the preceding vehicle is regarded as infinitely close to the stopped object, and the process proceeds to step ST16, With the same logic as that of the stop obstacle, the warning output judgment is performed by the discriminant of the equation (2).

Further, the determination result of step ST17 is (d
/ Dt) R <In the case of C, the slow relative speed, regarded as being the normal follow-up running at a constant inter-vehicle distance, vehicle speed V _f
Since the preceding vehicle speed V _a is almost equal, the equation 1 becomes the equation 3 shown below. In step ST18, the risk of collision is determined by the equation 3, and if the equation 3 is satisfied similarly, step ST19 Gives an alarm at.

[0023]

[Equation 3]

[0024]

However, in such a conventional obstacle detecting device, since the laser beam has the property of traveling straight, the laser beam tracks the preceding vehicle in a curve or the like. Therefore, there is a problem in that even if the operation of the device is normal, the important function of preventing collision cannot be fulfilled.

The present invention has been made in view of these problems, and an object thereof is to be able to detect an obstacle even in a curve or the like.

[0026]

An obstacle detecting apparatus according to the present invention includes a light emitting element which emits a light beam toward a front target object through a light projecting lens, and a light beam which is reflected by the front target object. A light-receiving element that receives light, and the light-receiving output of the light-receiving element is used to calculate the speed of the vehicle with respect to the front target and the inter-vehicle distance between the front target and the collision risk of the own vehicle based on the calculated distance. In an obstacle detection device equipped with an information processing circuit that issues an alarm signal when it is determined that the risk of occurrence is present, a steering angle sensor and a drive means for displacing the light projecting lens in parallel with the lens surface. And the information processing circuit calculates a displacement amount for moving the light projecting lens in either the left or right direction based on the output signal from the steering angle sensor, and corresponds to the calculated displacement amount. Control signal Serial supplied to the drive means.

[0027]

The device according to the present invention improves the collision prevention function by changing the laser beam emitting direction in proportion to the steering angle of the steering wheel so that the laser beam can follow the curve and check the inter-vehicle distance with the vehicle ahead even in the curve. .

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
1 to 5 are views showing an embodiment of the present invention. First, the configuration will be described with reference to FIG.
4 and 11 to 21, 31, 41, 42, 51, 52 are
The same or equivalent components as those of the conventional example shown in FIG. 6 are shown, and the same reference numerals are given to those parts and the description thereof will be omitted.

In FIG. 1, 32 is the vehicle speed sensor 31.
At the same time, the steering angle sensor that constitutes the traveling state detection unit 2 ′ detects the rotation angle and its rotation direction associated with the steering of the steering wheel (not shown), and outputs a signal indicating that. Reference numeral 33 denotes a displacement amount calculation circuit, which has a calculation formula showing the relationship between the displacement amounts of both the lenses 14 and 15 and the rotation angle and the rotation direction of the steering wheel, and calculates the rotation angle from the steering angle sensor 32. When a signal indicating the rotation direction is supplied, a displacement amount signal corresponding thereto is created and output. Reference numeral 22 denotes a drive circuit which is one of the constituent elements of the distance detection unit 1 ', and when it receives a displacement amount signal from the displacement amount calculation circuit 33, it controls the drive of a linear motor 64 described later in proportion to the magnitude of the signal. .

The linear motor 64 is a pair of an aluminum movable plate 61 having a pair of holes 65 for fixing and supporting the two lenses 14 and 15 and a pair of the movable plate 61. When the displacement amount signal is supplied from the displacement amount calculation circuit 33 through the drive circuit 22, the movable plate 61 is displaced in the left or right direction by an amount proportional to its magnitude. Excuse me.

The movable plate 61 is provided with a guide plate 62 having a U-shaped concave groove as shown in FIGS. 3 and 4 so as not to be displaced in the front-rear direction.
1 can be slid in the groove.

Next, the operation of the above configuration will be described.

For example, if the vehicle is traveling on a straight road or a road that curves very gently, the LD 13
The laser beam that has been emitted from the laser beam and has passed through the projection lens 14 within the range (indicated by the symbol G) shown by the solid line in FIG. 5 travels with a predetermined divergence angle (at this time, it is emitted from the LD 13). The divergence angle of the laser beam with respect to the central axis L is symmetrical with respect to the central line L). as a result,
Of the reflected light, the reflected light within the range indicated by the angle H indicated by the solid line is reflected by the vehicle ahead and is received by the PD 16 via the light receiving lens 15 (at this time, the central axis M of the light received by the PD 16 is In contrast, the spread range of the laser beam is symmetrical).

When the running vehicle approaches a large curve and the driver rotates the steering wheel to the right, for example, according to the size of the curve, the information is supplied to the displacement amount calculation circuit 33. To be done. As a result, a displacement amount signal corresponding to the steering state of the steering wheel is supplied to the drive coil 63 that constitutes the linear motor 64, and the movable plate 61 is moved by an amount proportional to the size of the curve, for example, the projection lens 14
The light receiving lens 15 and the light receiving lens 15 are both displaced in the F direction by the same displacement amount, and the light projecting lens 14 and the light receiving lens 15 are both displaced to the position indicated by the broken line.

As a result, the emission range of the laser beam emitted from the LD 13 moves from the range indicated by the reference symbol G to the range indicated by the reference symbol G ', and the light is projected in front of the device. That is, in FIG. 5, the emission direction of the laser beam moves from the portion indicated by the solid line to the portion indicated by the wavy line above.

Further, also in the light reception, the light within the range indicated by the wavy line shifted upward is received from the light within the range indicated by the solid line. That is, when the handle is turned to the right, the laser beam from the LD 13 is emitted toward the front right, and the reflected light from the front right is received by the PD 16.

[0037]

As described above, according to the present invention, the emitting direction of the laser beam and the receiving direction of the laser beam change according to the steering angle of the steering wheel. Since it operates normally, a collision warning can be issued accurately, which has the effect of contributing to traffic safety.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing an obstacle detection device according to an embodiment of the present invention.

FIG. 2 is an explanatory plan cross-sectional view of an obstacle detection device.

FIG. 3 is an enlarged explanatory view of a main part for explaining the present invention.

FIG. 4 is a cross-sectional explanatory view of a main part for explaining the present invention.

FIG. 5 is an operation explanatory view for explaining the operation of the present invention.

FIG. 6 is a circuit block diagram showing a conventional obstacle detection device.

FIG. 7 is a timing diagram showing a time relationship of signals of respective units in the distance detecting units of the related art and the present case.

FIG. 8 is a flowchart showing a processing flow in the arithmetic circuit of FIG.

FIG. 9 is an external perspective view of the obstacle detection device of the related art and the obstacle detection device of the present case.

[Explanation of symbols]

 13 Laser diode (LD) 16 Photodiode (PD) 22 Drive circuit 32 Steering angle sensor 33 Displacement amount calculation circuit 61 Movable plate 62 Guide plate 63 Drive coil 64 Linear motor

Claims (1)

[Claims] 1. A light emitting element (13) for emitting a light beam toward a front target object through a light projecting lens (14) and a light receiving element (16) for receiving the light beam reflected by the front target object.
And the speed of the host vehicle with respect to the front target object and the inter-vehicle distance from the front target object are calculated from the light reception output of the light receiving element, and the risk of collision of the own vehicle is determined based on the calculated distance. In an obstacle detection device provided with an information processing circuit that issues an alarm signal when it is determined that the steering angle sensor (32) and the light projecting lens (14) are driven to be displaced in parallel with the lens surface. Means (22, 64) are provided, and the information processing circuit includes the steering angle sensor (32).
A displacement amount for moving the light projecting lens (14) in any of the left and right directions is calculated based on an output signal from the drive means (22, 64), and a control signal corresponding to the calculated displacement amount is calculated. An obstacle detection device characterized by being supplied to.