JPH05223933A - Obstacle detection apparatus - Google Patents

Abstract

PURPOSE:To obtain an obstacle detection apparatus wherein an object especially in the rear region can be detected prior to falling into a dangerous state. CONSTITUTION:The title apparatus is provided with the following: first sensor means (A, a) provided with a detection range nearly at the side part of a vehicle in order to detect a stationary object; second sensor means (B, C, D, b, c, d) provided with a detection range in the back further from the detection range of the first sensor means in order to detect a moving obstacle; and a recognition means (20) which processes first output signals from the first sensor means and individual output signals from the second sensor means and which discriminates and recognizes the moving obstacle and the stationary object. When it is assumed that the stationary object has been detected by means of the output signals from the first sensor means, the recognition means recognizes that the stationary object has been detected by giving priority to the assumption based on the output signals from the first sensor means when the moving object is detected by means of the second output signals.

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 recognizing the presence of a moving obstacle behind a vehicle.

[0002]

2. Description of the Related Art A number of researches and proposals for detecting obstacles have been made in order to prevent accidents while a vehicle is running. For example, in Japanese Examined Patent Publication No. 55-45412, a signal obtained by detecting the ground speed of the vehicle and the steering angle of the steering wheel is detected so that non-obstacles such as road shoulders and median strips are not mistaken as obstacles. Corresponding to each value, the vehicle detected by the radar sensor is extracted from the range cut function generator as an output warning area value indicating the allowable shortest distance between the radar sensor and the roadside in the obstacle detection area of the radar sensor. The alarm signal is issued only when the mutual distance between the object and the object is smaller than the warning area value. Further, in Japanese Examined Patent Publication No. 3-27048, a plurality of radar sensors are provided to detect obstacles in the surroundings.

[0003]

As described above, the conventional obstacle monitoring is to monitor an obstacle in front of or on the side of the vehicle. However, on highways, etc., people often fall into a dangerous state because they do not notice the car in the blind spot.
There is an increasing demand for detection technology for motorcycles. A problem with the detection of obstacles in the rear-side area is the inability to distinguish lateral vehicles from guardrails in particular, ie inability to distinguish between moving and stationary objects. This is because, at present, it is best to detect the presence or absence of an obstacle of about 1 m by a back sonar using ultrasonic waves, a clearance sonar, or the like. Therefore, it is an object of the present invention to propose an obstacle detection device capable of detecting an obstacle in the rear area before falling into a dangerous state.

[0004]

[Means for Solving the Problems] and

According to the present invention for achieving the above object, there is provided a first sensor means having a detection range substantially lateral to the vehicle for detecting a stationary object, and the first sensor means for detecting a moving obstacle. Second sensor means having a detection range further behind the detection range of the sensor means, and processing and moving the first output signal of the first sensor means and each output signal from the second sensor means. Recognizing means for distinguishing between an obstacle and a stationary object and detecting a moving obstacle by the second output signal when it is estimated that the stationary object is detected by the output signal from the first sensor means. In this case, the recognizing means for recognizing that the stationary object has been detected is prioritized based on the estimation based on the output signal from the first sensor means. Further, the configuration of the present invention to achieve the above-mentioned object, a detection range is a substantially side rear of the vehicle, a plurality of distance sensors sequentially shifted in the front-rear direction, receiving output signals of the plurality of distance sensors, Among the distance sensors, there is provided a recognizing means for recognizing that the moving obstacle is approaching when the rear sensor and the front sensor sequentially detect the object. The obstacle detection device of the present invention having these configurations can reliably detect the approach of a moving obstacle on the rear side of the vehicle.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a mounting position of an ultrasonic transducer (hereinafter abbreviated as “sensor”) and its detection direction / detectable distance in a vehicle equipped with the obstacle detection device of the embodiment. This vehicle has A-D and a-
A total of eight ultrasonic sensors of d are attached. The role of these sensors is as follows.

A: Detection of the left guardrail. By using a frequency of 50 KHz or higher and measuring the frequency of the reflected signal, the relative speed of the left-side obstacle with respect to the own vehicle speed is detected. B to D: Detection of a vehicle approaching from the rear side on the left side. By using a frequency of 50 KHz or less and measuring the time until the reflected signal is received, the distance to the obstacle on the left rear side is obtained. The frequencies used by the four sensors are different, and the difference is about 5 KHz. a: Detection of the right guardrail. 50KH as frequency
The relative speed of the right-side obstacle with respect to the own vehicle speed is detected by measuring the frequency of the reflected signal using z or more. b-d: Detection of a vehicle approaching from the rear side on the right side. By using a frequency of 50 KHz or less and measuring the time until the reflected signal is received, the distance to the obstacle on the right rear side is obtained. The frequencies used by the four sensors are different, and the difference is about 5 KHz.

Generally, a vehicle runs on the right side or the left side of the road on a two-lane road, and thus two sets of sensor groups are required. The detection distances of B, C, D, b, c, and d, which are the sensors for detecting the rear side, are about 7-8 m in this embodiment. FIG. 2 is a block diagram of an obstacle detection device mounted on this vehicle. Reference numeral 10 is a signal processing unit that processes the echo signal from the ultrasonic sensor. The vehicle speed V of the vehicle is detected by the vehicle speed sensor 11 and input to the processing unit 10. For the sensors A and a, the signal processing unit 10 obtains the relative speed difference with the obstacle from the frequency of the transmitted ultrasonic wave, the frequency of the echo signal, and the vehicle speed V.
The processing unit 10 outputs to the recognition unit 20 the relative speed difference between the sensors A and a and the lateral obstacles obtained. Further, regarding the sensors B, C, D, b, c, d, the processing unit 10
Calculates the time required for transmission and reception from the difference between the transmission time of each ultrasonic signal and the reception time of the echo signal. The distance to the obstacle is calculated from this time and the speed of sound. Sensor B,
Since the transmission frequencies from C, D, b, c, and d are shifted by about 5 KHZ, there is no risk of interference. The echo signal processing unit 10 passes the distance information to the obstacle obtained by the sensors B, C, D, b, c, d to the recognition unit 20.

The operation of the recognition section 20 will be outlined. The distinction between a stationary object such as a guardrail and a moving obstacle such as an approaching vehicle is recognized as follows. That is, for example, 2
How these sensors react when a guardrail is on the left side while driving on the left lane of a lane road will be described. In such a case, a reflected signal is detected by the A sensor on the left side, but the relative distance between the vehicle and the guardrail does not change so much, and thus the detected relative speed hardly changes. Further, although signals are detected also in the B, C, and D sensors, they are ignored.

Next, the case where a rear vehicle approaches from the right side while traveling in the left lane of a two-lane road will be described. In such a case, no signal would be detected at sensor a. Then, first, it is detected by the sensor d, and then the sensor c.
Would then be detected by sensor b and then by sensor b. When a signal is detected by the sensor group in such a manner, it is determined that the vehicle is approaching from the right rear, and an alarm is issued and avoidance control is performed.

Next, how these sensors react when there is a guardrail on the right side while traveling on the right lane of a two-lane road will be described. In such a case, a reflection signal is detected by the a sensor on the right side, but the relative distance between the host vehicle and the guardrail does not change so much, so the detected relative speed does not change much. Also, b,
Signals are also detected by the c and d sensors, but they are ignored.

Next, a case where a vehicle behind is approaching from the left side while traveling in the right lane of a two-lane road will be described.
In such a case, no signal would be detected by sensor A. Then, first, the sensor D detects, and then the sensor C.
Should be detected by sensor B and then by sensor B. When a signal is detected by the sensor group in such a manner, it is determined that the vehicle is approaching from the left rear, and an alarm is issued and avoidance control is performed.

In the avoidance control of this embodiment, for example, when a rear vehicle approaches from the left side while traveling in the right lane, the driver tries to turn the steering wheel into the sensor B, C and D areas of FIG. If so, the steering wheel is locked so that steering cannot be performed. Further, as a matter of course, if a vehicle approaching from behind is detected, an alarm is issued.

The control procedure in the recognition unit 20 will be described with reference to FIG. First, in step S2, the observation result from each sensor is input. In step S4, it is checked whether an object is detected by the sensor A or the sensor a. If an object is detected by these two sensors,
In step S14, the relative speed difference between the detected object and the vehicle is calculated. If it is determined that there is no speed difference, it is determined in step S16 that there is a stationary object on the side of the detection range of the sensor (on the left side for the A sensor, on the right side for the a sensor). And step S1
Proceed to step 6 and check if there is a vehicle approaching from behind. This is because even if there is a stationary object such as a guardrail on the side, another moving obstacle (following vehicle) may be on the rear side.

On the other hand, if it is determined in step S14 that there is a speed difference, it means that a moving obstacle may approach. Therefore, step S
At 18, it is checked whether the speed difference is within a certain range. This is because, even if there is a speed difference, if it is within a certain range, it can be determined that the relative speed difference is detected by the change in the relative distance between the guardrail and the own vehicle. Therefore, if the speed difference is within a certain half, it is determined as a stationary object, and if not, step S20.
In step S22, a warning is issued, and avoidance control is performed in step S24.

On the other hand, if no object is detected by the sensors A and a for detecting the relative speed difference in step S4, the sensors B, C and D are detected in step S6.
Check whether an object is detected in b, c, or d. If detected, it is checked in step S8 whether the detection order is detected by the sensor in the distant detection range (D or d) to the sensor in the short range detection range. The judgment in step S8 is YE
If it is S, a warning is issued in step S10, and avoidance control is performed in step S12. As described above, the obstacle detection device of this embodiment can distinguish the stationary object from the moving obstacle. In particular, as is clear from FIG. 1, since the detection areas of the sensors B, C, D, b, c, and d are blind spots of the driver, the significance of distinguishing a moving obstacle from a stationary object in this area is significant. large.

Next, an example in which the obstacle recognition technique of the above embodiment is further applied to autonomous traveling control will be described. In this application example, traveling along the guardrail is autonomously performed. In conventional autonomous driving, a white line is recognized by image recognition, and the white line is traced. The problem of applying this conventional autonomous traveling control to obstacle detection is that the traveling path cannot be determined if the white line is not an obstacle and there is no white line.

Therefore, as shown in FIG. 4, the distances L1 and L2 to the guardrails detected by the sensors a and d, respectively.
The steering is controlled so that there is no difference with This steering control is performed if it is determined in step S16 in FIG. 3 that the obstacle is a stationary object (guardrail). The present invention can be variously modified without departing from the spirit thereof. For example, in the embodiment of FIG. 1, the functions of the sensor A and the sensors B, C and D are different. However, the present invention is not limited to this, and for example,
Not only can the sensors B, C, and D be provided with the function of measuring the reflection time and the function of detecting the Doppler effect, the same effect can be expected, but the sensor A can be eliminated.

[0018]

As described above, according to the obstacle detecting device of the present invention, it is possible to reliably detect the approach of the moving obstacle on the rear side of the vehicle. Particularly, according to the obstacle detection device of the first item, it is possible to reliably distinguish the stationary object from the obstacle. Further, according to the obstacle detection device of the fifth item, the approach of the vehicle can be detected in the blind spot area of the driver.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the arrangement of sensors and the like in an embodiment system to which the present invention is applied.

FIG. 2 is a block diagram showing the configuration of an obstacle detection device of the embodiment of FIG.

FIG. 3 is a flowchart illustrating a control procedure of the embodiment.

FIG. 4 is a diagram illustrating a method of autonomously traveling while following a guardrail in a modified example of the present invention.

[Explanation of symbols]

 10 echo signal processing device, 20 recognition processing unit, 30 avoidance / warning control unit, 40 warning device, 50 handle.

Claims (6)

[Claims] 1. A first sensor means having a detection range substantially lateral to the vehicle for detecting a stationary object, and further behind a detection range of the first sensor means for detecting a moving obstacle. A second sensor means having a detection range, a first output signal of the first sensor means and each output signal from the second sensor means are processed to distinguish a moving obstacle from a stationary object. Recognizing means for recognizing, the first
When a moving obstacle is detected by the second output signal when it is estimated that the stationary object is detected by the output signal from the sensor unit, the estimation based on the output signal from the first sensor unit is prioritized. And an recognizing means for recognizing that a stationary object has been detected. 2. The obstacle detection device according to claim 1, further comprising: an avoidance unit that performs an avoidance control by receiving a recognition result when the recognition unit recognizes a moving obstacle, and the recognition unit is stationary. A means for stopping the avoiding means in response to the recognition result when an object is recognized is provided. 3. The obstacle detection device according to claim 1, wherein the second sensor means comprises a plurality of ultrasonic sensors whose detection ranges are sequentially shifted in the front-rear direction, and the recognition means comprises the plurality of ultrasonic sensors. It is recognized that the moving obstacle is approaching when the sensors from the rear of the sound wave sensor to the front of the sound sensor sequentially detect the object. 4. The obstacle detecting device according to claim 1, wherein the first sensor means is an ultrasonic sensor in a high frequency region for detecting a relative speed with respect to a stationary object, and the second sensor means is It is an ultrasonic sensor in the low frequency region for detecting the distance to a moving obstacle. 5. A plurality of distance sensors having a detection range substantially rearward of the vehicle and sequentially shifted in the front-rear direction, and an output signal of the plurality of distance sensors, the distance sensor being the rear sensor. An obstacle detection device, comprising: a recognition unit that recognizes that a moving obstacle is approaching when a sensor in front detects the object sequentially. 6. The obstacle detecting device according to claim 5 further comprises an avoiding means for performing avoidance control in response to the recognition result when the recognizing means recognizes a moving obstacle.