JPH08153300A - Obstacle detecting device - Google Patents

Abstract

PURPOSE: To restrict alarm generation at the time of a steering operation on a curved road, etc., by providing a sensor detecting an acceleration component in the horizontal direction and stopping the output of an alarm signal when a sensor output becomes more than a prescribed value. CONSTITUTION: A horizontal G sensor 22 is what is called a gravity-type acceleration sensor consisting of a potentiometer and a pendulum. It detects the acceleration acting on the vehicle in the horizontal direction and outputs a detection signal to an arithmetic circuit 41' when the value becomes more than a prescribed value. When the size of the signal from a low-pass filter 23 is judged to be smaller than a prescribed size K, the arithmetic circuit 41' issues alarm from alarm equipment 52. But, when the size of the signal from the low-pass filter 23 is judged to be larger than the prescribed size K, the steering operation, for example, is executed and alarm generation is stopped since it is judged that the acceleration is acted in the horizontal direction of the vehicle. A judgement reference value K is equivalent to the acceleration of 0.03G which is generated at the time of running in the curved road with 700m radius by the speed of 100km/h.

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 for detecting an obstacle ahead of a vehicle to prevent a collision accident from occurring.

[0002]

2. Description of the Related Art As a conventional obstacle detecting device, there is one shown in FIG. 5, for example. In the figure, 1 is a distance detection unit that detects a distance between a vehicle and an obstacle by using a laser beam emitted from a laser diode (hereinafter referred to as LD), and 2 is a vehicle such as a vehicle speed. Is a running state detection unit that detects the running state of the vehicle.

Reference numeral 3 designates a 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, the drive signal generating circuit 11 receives the distance detection command signal, and the drive signal generating circuit 11 receives the LD light emission signal shown in FIG.
Send to. The LD switching driver 12 receives the LD
4 (b), (c), based on the light emission signal (a).
The signal shown in (d) is transmitted, and the LD-L, LD-C, and LD-R of the LD array 13 as the light emitting means are made to sequentially 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. 6 (e). 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, S
Proceeding to the TART step, the CP forming the arithmetic circuit 41
U, RAM, etc. are initialized. Next, step S
At T11, a distance signal indicating the information of the distance R to the obstacle from the counter 20 of the distance detecting unit 1 and a 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 at a predetermined cycle. Are taken into the arithmetic circuit 41.

Then, in step ST12, the distance signal R is converted into a display signal, which is sent to the distance display 51 and displayed.
Next, in step ST13, 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 a least squares method, and the vehicle speed V _{a of the} preceding vehicle is relative to the own vehicle speed V _f and the relative speed (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.

[0015]

[Equation 1]

Therefore, first, in step ST14, the relative speed (d / dt) R and the vehicle speed _Vf are compared, 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 ST15, and since V _a = 0 in Formula 1, the collision law is calculated according to the following formula 2 Determine the risk.

[0017]

[Equation 2]

When the equation 2 is satisfied, there is a risk of collision with an obstacle, and the process proceeds to step ST18 to generate an alarm signal and send it to the alarm notifying unit 4, and the alarm device 52 causes a danger. A warning for avoidance is issued.

On the other hand, as a result of the judgment in step ST14,
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 accuracy of dt) R may not be strict, the calculation error may give an erroneous alarm. Therefore, in the case of a preceding vehicle in which an obstacle moves, the relative speed (d / d) is calculated in step ST16.
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 fast 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 ST15. 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 ST16 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 ST17, the danger of a collision is determined by the equation 3, and if the equation 3 is satisfied similarly, in step ST18. Give an alarm.

[0022]

(Equation 3)

[0023]

However, in such a conventional obstacle detecting device, a roadside road sign is detected when a vehicle is traveling on a curved road to generate an alarm, or in order to avoid a collision, Even when the lane change was started to pass the vehicle, the alarm was not immediately stopped and the alarm was continuously issued until the host vehicle stopped detecting the vehicle in front.

However, when the driver is operating the steering wheel in this way, there is almost no probability that the driver is inattentive to the front, which may cause the driver to feel annoyed. In addition, if the warnings are generated frequently in this way, the driver's ears may become accustomed to the warning sound, and the response may be delayed when it is really dangerous.

As a means for this, for example, a method of detecting the steering angle of the steering wheel by using a steering wheel angle sensor and stopping the generation of an alarm by using the signal can be considered. It is still expensive as a component, and it is necessary to prepare a sensor according to the steering wheel of each vehicle type, which is not suitable as a component of a product having high mass productivity.

The present invention has been made by paying attention to such a problem, and when the driver is operating the steering wheel while changing a curve or a lane, the alarm is suppressed from being generated and the alarm is not issued. The purpose is to increase effectiveness.

[0027]

An obstacle detecting device according to the present invention is provided with a sensor for detecting the magnitude of an acceleration component acting in the lateral direction of a vehicle in a case of the obstacle detecting device, When the size becomes equal to or larger than the predetermined value, the information processing circuit stops outputting the alarm signal for notifying that the risk of collision is high.

[0028]

The device according to the present invention is an inexpensive device because it suppresses the generation of an alarm by detecting the acceleration acting in the lateral direction of the vehicle. Further, since the sensor is provided in the case, it can be used for adjustment when the device is mounted horizontally on the vehicle.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, the configuration different from the configuration shown in FIG. 5 is the horizontal G sensor 22 and the arithmetic circuit 41 ′, and the other configurations are the same or equivalent, and therefore, the same reference numerals are given to them. The description is omitted.

The lateral G sensor 22 is a potentiometer 22.
A so-called gravitational acceleration sensor composed of a and a pendulum 22b is attached to a circuit board 60 in a case 61 in which the circuit shown in FIG. Then, when the value exceeds a predetermined value, a detection signal is output to the arithmetic circuit 41 '. The rotation angle of the pendulum 22b is determined by the potentiometer 2
The electric signal is converted into an electric signal by 2a and supplied to the arithmetic circuit 41 ', and the circuit board 60 is mounted so as to be perpendicular to the traveling direction of the vehicle, that is, to face the traveling direction.

As the gravity type acceleration sensor, in addition to the pendulum method, a conductive fluid such as mercury is sealed in a V-shaped tube, and an electrode is provided above the V-shaped tube to provide an electrode for a predetermined acceleration or more. It may have a switch configuration in which is turned on by a fluid. Further, it goes without saying that an acceleration sensor using a centrifugal force that detects acceleration in the left-right direction may be used in addition to the gravity acceleration sensor.

Since the pendulum 22b faces the direction of gravity, the pendulum 22b is looked into through the transparent glass panel 62, and the index attached to the tip of the pendulum 22b is
By mounting the case 61 on the vehicle side so as to match the index 22c provided on the circuit board 60, the device can be easily mounted horizontally.

A low-pass filter 23 has a cut-off frequency set so that the natural frequency of the pendulum 22b of the lateral G sensor 22 can be canceled. Noise is removed in response to the detection output from the lateral G sensor 22 and output. To do.

The arithmetic circuit 41 ', as shown in FIG.
The following points are different from the flowchart of FIG. 5 showing the function of the arithmetic circuit 41 in FIG.

That is, in FIG. 4, step ST19 is added to the flowchart shown in FIG. In this step ST19, after it is determined in step ST15 or step ST17 that an alarm should be issued, the arithmetic circuit 41 'sets the low pass filter 23.
If it is determined that the signal from the low-pass filter 23 is smaller than the predetermined value K, an alarm is issued in step ST18, but it is determined that the signal from the low-pass filter 23 is higher than the predetermined value K. In this case, for example, the steering wheel is operated, it is determined that the acceleration is applied in the left-right direction of the vehicle, the alarm generation is stopped, and step ST11 is performed.
Return to

The value K, which is a criterion for determining whether or not the signal from the low-pass filter 23 should stop issuing the alarm, is a value corresponding to an acceleration of 0.03 G, for example, at a vehicle speed of 100 km / h. It corresponds to the acceleration in the left-right direction that occurs when traveling on a curve with a radius of 700 m.

[0037]

As described above, according to the present invention, the driver can be alerted in a timely and appropriate manner, so that the effect of the alert can be enhanced.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a state in which an acceleration sensor is mounted in a case in the obstacle detection device in which the circuit in FIG. 1 is housed.

3 is a cross-sectional view taken along the line AA of the obstacle detection device shown in FIG.

4 is a flowchart showing a processing flow of an arithmetic circuit in FIG.

FIG. 5 is a block diagram showing a conventional obstacle detection device.

FIG. 6 is a timing diagram showing a time relationship of signals of respective parts in the distance detecting part.

FIG. 7 is a flowchart showing a processing flow in the arithmetic circuit of FIG.

[Explanation of symbols]

 13 light emitting means (LD array) 16 photodiode 18 threshold value generating circuit 19 comparator 20 counter 22 lateral G sensor 22a potentiometer 22b pendulum 22c index 41, 41 'arithmetic circuit 52 alarm 62 transparent glass panel

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G01S 17/93

Claims (1)

[Claims] 1. The risk of collision of the host vehicle with respect to the front target object is judged based on the free running distance of the own vehicle, the relative speed of the own vehicle and the front target object, and it is judged that there is a danger of a rear-end collision. In an obstacle detection device in which a case is provided with an information processing circuit for generating an alarm signal in the case of a case, a sensor for detecting the magnitude of an acceleration component acting in the lateral direction of the vehicle is provided in the case, and the sensor is provided. The obstacle detection device, wherein the information processing circuit stops outputting the alarm signal when the output magnitude exceeds a predetermined value.