JPS639875A - Detector for rear obstacle - Google Patents

Abstract

PURPOSE:To eliminate a dead angle, to securely detect a rear obstacle and to secure rear safety, specially, at the time of the start of a vehicle by setting the irradiation direction of an ultrasonic sensor to two directions of a short- distance and a long-distance point. CONSTITUTION:The vehicle is equipped with the ultrasonic sensor 1 installed on a rear spoiler, etc., so as to detect the rear obstacle, its signal processing circuit 2, and a warning display device 3 which generates a warning signal when the signal processing circuit 2 detects the obstacle, and the irradiation direction of the ultrasonic sensor 1 is switched by an actuator 4 between two directions of the long-distance and short-distance points. Then, the actuator 4 is driven by an actuator control circuit 5 to irradiate the short-distance point when the vehicle starts and the irradiation direction is switched to the long- distance point direction after the safety is confirmed; when the detected obstacle enters the short-distance area, the irradiation direction is switched again to the short-distance direction. Further, when the vehicle starts running backward, the ultrasonic sensor 1 is directed to the short-distance point firstly through the circuit in response to a gear shift signal 6.

Description

[Detailed description of the invention]

I. Field of Industrial Application This invention relates to a vehicle immersion warning system using an ultrasonic sensor, and more particularly to a rear obstacle detection device for a vehicle that can ensure safety when the vehicle starts backwards. .

[Conventional technology]

Conventionally, as a rear warning system for a vehicle of this type, there has been one as disclosed in, for example, Japanese Unexamined Patent Publication No. 59-29536. This system has two sets of ultrasonic sensors attached to the rear of the vehicle so that their irradiation directions differ, and by sequentially switching channels, a gear shift position sensor detects whether the vehicle is in reverse, and a gear shift position sensor detects whether the vehicle is in reverse. According to the sensor signals of the brake sensor, which detects whether the vehicle is running, and the vehicle speed sensor, which detects whether the vehicle speed is below a certain level (for example, 20 km/h or below),
Depending on the reception status of each ultrasonic sensor, the presence or absence of an obstacle behind the vehicle is detected, and the distance and direction of the detected obstacle are determined. When an obstacle is detected, an alarm is issued, and the distance to the obstacle (111I) and The direction is displayed.

Problem 1 to be Solved by the Invention By the way, in the above-mentioned prior art, two sets of ultrasonic sensors are fixedly attached to the rear part of the vehicle body, for example, to the rear bumper, with the irradiation direction being approximately horizontal, and the channels are switched while detecting rear obstacles. Since it was designed to detect objects, there were many blind spots, and in particular, JFI was unable to timely sense the short distance behind the vehicle, which caused problems in terms of safety confirmation. Further, since the ultrasonic sensor was mounted close to the horizontal direction, there were problems such as dust accumulation on the irradiation section. The present invention eliminates blind spots by moving the irradiation direction of the ultrasonic sensor between two directions, a short distance point and a long distance point, so that rear obstacles can be reliably detected and rear safety can be ensured, especially when the vehicle starts. The purpose is to [Means for Solving the Problems] A rear obstacle detection device according to the present invention includes an ultrasonic sensor installed in a rear spoiler or the like to detect rear obstacles, a signal processing circuit for the ultrasonic sensor, and a signal processing circuit for the ultrasonic sensor. In a vehicle equipped with an alarm display that issues an alarm when the sensor detects an obstacle, a switching mechanism that switches the irradiation direction of the ultrasonic sensor to two directions, a far-field point and a short-range point, and when the vehicle starts. An irradiation direction switching control circuit that irradiates a short distance point, switches the irradiation direction to a long distance point after confirming safety, and switches the irradiation direction again to a short distance point when a detected obstacle enters the short distance point. It was set up.

[For production]

Based on the above configuration, the irradiation direction switching control circuit is
When starting the vehicle backwards, the gear V shift signal drives the switching mechanism to first shift the irradiation direction of the ultrasonic sensor, which is rotatably installed on the girder boiler or wing at the rear of the vehicle body, toward a nearby point. When the ultrasonic irradiation detects that there are no obstacles, the switching mechanism is then switched so that the irradiation direction is directed toward a distant point, thereby confirming safety during backward travel. An obstacle is detected during this long-distance irradiation, and when the detected obstacle enters the short-distance point as the vehicle is traveling backwards, the irradiation direction of the ultrasonic sensor is switched back to the short-distance point to avoid creating a blind spot. To ensure that obstacles are detected.

[Example 1] Hereinafter, an example of the present invention will be described and explained with reference to the drawings. Fig. 1 shows the irradiation direction of the ultrasonic sensor. Fig. 2 shows the circuit configuration. In the figure, 1 is an ultrasonic sensor rotatably attached to a heavy girder boiler or wing, etc.; 2 is a signal processing circuit; An ultrasonic oscillation circuit 21. An ultrasonic oscillation circuit 21. An ultrasonic oscillation circuit 21. An ultrasonic oscillation circuit 21. The ultrasonic oscillation circuit 21 generates a signal, irradiates it from the ultrasonic sensor at predetermined intervals, and processes the received waves. Ultrasonic transmitter circuit 23
．． Receiving circuit 24. Received wave amplification circuit 25. bandpass filter 2
6. It is composed of a long-distance/short-distance filter 27 and the like. 3 compares the processed received wave with received waves at a predetermined distance to detect the presence or absence of an obstacle, and l! i This is a circuit that issues an alarm when it is determined that there is a harmful object, and also displays the distance to the obstacle.Distance comparator 311Display control circuit 32. Il
l Display device 3 consisting of a plurality of lamps indicating the distance to the antique item
3. It consists of a buzzer 34 and the like. 4 is an actuator consisting of a W-motor M, etc., and its ultrasonic irradiation direction directs the ultrasonic sensor 1 to a short distance point (0+
It is rotated in the vertical direction so that it can be switched between two directions: ~1+)I and a long distance point (1fi1~21m)■. 5 is an actuator control circuit, and 6 is a gear shift position signal. Next, the operation will be explained with reference to the ultrasonic signal emission/reception waveform diagram shown in FIG. The signal processing circuit 2 oscillates an ultrasonic signal of about 40K I-Iz in an ultrasonic oscillation circuit 2, and generates ultrasonic waves at a predetermined interval from a transmission circuit 23 via a gate signal at a predetermined interval from a transmission interval generation circuit 22. A pulse signal is applied to the ultrasonic sensor 1 and emitted (Fi) in the irradiation direction.The irradiated ultrasonic waves are deflected from the road surface or obstacles in the irradiation direction, and are received by the ultrasonic sensor 1. It becomes an electric signal, passes through the receiving circuit 24, is amplified by the received wave amplification circuit 25, and after noise etc. are removed by the bandpass filter 26, it is input to the long-distance/short-distance filter 21. This filter 27 ■゛If the ultrasonic sensor 1 is simply pointed in the direction of the nearby point with the same direction detection wave, it will detect the road surface, making it difficult to distinguish between an obstacle and the road surface. In addition, when the ultrasonic sensor 1 is directed in a short distance direction, the received waves of 1ff1 to 2I11 at long distance points are cut off, so that it is possible to easily distinguish between obstacles and the road surface. , the received wave signal enters the alarm display circuit 3, and the distance comparator 3
1, the presence or absence of an obstacle is detected based on the response time difference of reflected waves, and if it is determined that there is an obstacle, a buzzer 34 is sounded via the display control circuit 32, and a lamp corresponding to the obstacle distance of the lamp device 33 is turned on. do. In this obstacle detection operation, when the ultrasonic sensor 1 is irradiating the far point II in the force direction, when the distance comparator 31 detects that the obstacle is within 1 m, the detection signal is sent to the actuator control circuit 5. and drive the actuator 4 by the output of the control circuit 5,
An ultrasonic sensor 1 is rotated downward to direct its ultrasonic irradiation direction toward a short-distance point, and an obstacle is reliably detected without creating a blind spot. Further, when the vehicle starts backing up after parking or stopping, the actuator control circuit 5 drives the actuator 4 to first activate the ultrasonic sensor 1 using a gear shift signal that is turned on when the gear is put into reverse. Ultrasonic waves are irradiated in the direction of the nearby point, and after confirming safety based on the reflected waves, the actuator 4 is driven in the opposite direction by No. 4B, which detects the absence of obstacles from the distance comparator 31. The sound wave sensor 1 is directed toward a distant point (2) to detect the presence or absence of obstacles behind the vehicle as it travels, thereby ensuring safety when traveling in reverse. During this backward running, if an obstacle is detected and the obstacle is within 1rR, the irradiation direction of the ultrasonic sensor 1 is changed again to the nearby point
Switch direction. [Effects of the Invention] As described above, according to the present invention, the irradiation direction of the ultrasonic sensor for detecting rearward obstacles can be switched between two directions: the direction of a far point and the direction of a near point. So,
Obstacles can be reliably detected without creating blind spots, and in particular, safety can be ensured by detecting the presence or absence of obstacles immediately behind the vehicle body before starting the vehicle from behind. Furthermore, since the ultrasonic sensor is mounted so as to face downward, it is possible to reduce the amount of dust adhering to the irradiation surface and prevent problems caused by dust.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention; Figure 1 is a side view showing how the ultrasonic sensor is installed; Figure 2 is a block diagram showing the configuration of the obstacle detection device; The figure is a waveform diagram of transmitted waves and received waves of an ultrasonic sensor. 1... Ultrasonic sensor, 2... Signal processing circuit, 3...
- Alarm display circuit, 4... Actuator, 5... Actuator control circuit, 6... Gear A7 shift signal. Patent Applicant Fuji Heavy Industries Co., Ltd. Representative Patent Attorney Jundo Kobashi Patent Attorney Susumu Murai Figure 1

Claims (1)

[Claims] In a vehicle equipped with an ultrasonic sensor installed in a rear spoiler or the like to detect rear obstacles, a signal processing circuit thereof, and an alarm display device that issues an alarm when this signal processing circuit detects an obstacle. , a switching means for switching the irradiation direction of the ultrasonic sensor to two directions, a far point and a short distance point; when the vehicle starts, the irradiation direction is irradiated to the short distance point, and after safety confirmation, the irradiation direction is switched to the far point direction, and the detection is performed. 1. A rear obstacle detection device comprising: an irradiation direction switching control circuit which switches the irradiation direction again to the direction of the short distance point when the obstacle enters the short distance point.