JPS60249078A - Obstruction finder for vehicle - Google Patents

Abstract

PURPOSE:To expand the range for finding an obstruction by scanning and moving a sensor which transmits intermittently a signal having directivity and receives a reflection signal. CONSTITUTION:The transmission and reception sensor 2 which transmits intermittently the signal having directivity and receives the signal reflected from the obstruction is provided to the corner part 1b of a vehicle 1. The sensor 2 is scanned and moved via a scanning and moving mechanism 3, by which the range for finding the obstruction is expanded.

Description

[Detailed description of the invention] Ru.

Recently, a device has been developed in which an ultrasonic transducer is installed in the rear of a vehicle so that it can be swung, and the ultrasonic wave is scanned to detect obstacles in the vicinity of the vehicle. .

For example, Japanese Patent Application Laid-open No. 57-168178 discloses a device in which a transmitter/receiver unit that is swingably installed in the center of the rear bumper of a vehicle emits directional ultrasonic waves while making a scanning motion, and the emitted ultrasonic waves are The time difference (reflector width time) between hitting an obstacle and returning as a reflected signal is detected, and appropriate correction is made to this reflector width time to determine how far behind the vehicle the obstacle is. A device is disclosed in which the information can be visually displayed on a display unit.

However, in such a device, since the transmitter/receiver is located in the center of the rear of the vehicle, the @L area that can be searched is limited to an angular range within approximately 180 degrees behind the vehicle. .

In view of such circumstances, the present invention has been made to expand the range in which obstacles can be searched, and in particular, in order to search for obstacles that are close to the vehicle, a directional search signal is intermittently transmitted. The present invention provides an object detection device for use in a vehicle, the gist of which is a transmitting/receiving sensor installed in a corner of the vehicle, which performs a scanning motion while receiving reflected signals from the transmitted signal when it hits an obstacle. The purpose is to

Hereinafter, one embodiment will be described with reference to the attached drawings.

FIGS. 1 and 2 show plan views of a vehicle to which the present invention is applied. In the figure, 1 is a vehicle, 2 is a transmitting/receiving sensor capable of scanning motion for intermittently transmitting and receiving ultrasonic waves, 3 is an operation movement mechanism for operating the transmitting/receiving sensor 2, and 4 is an obstacle.

The transmission/reception sensor 2 is disposed at one corner 1b of a rear bumper 1a of the vehicle 1, and the scanning movement mechanism 3 is supported by this bumper 1a.

The operation interlocking mechanism 3 uses the output @5a of the stepping motor 5.
A rotating table 6 is mounted on the rotating table 6, and the transmitting/receiving sensor 2 is provided on the rotating table 6. FIG. 4 is a block diagram showing a schematic configuration of a search system A used when scanning the transmission/reception sensor 2 to search for an obstacle 4 located behind the vehicle 1.

This system A is a microcomputer 30
0, and the obstacle 4 detected by the scanning of the transmitter/receiver 2 can be displayed as visual dot information on the display section 8 as shown in FIG. That is, as shown in FIG. 4, system A includes a transmitting/receiving sensor 2, a transmitting circuit 100 that outputs an intermittent signal of a predetermined frequency after the exploration signal, and a transmitting/receiving sensor 2.
After receiving the reflected signal detected by the transmitting/receiving sensor 2 and emitting the exploration signal, the time it takes for it to hit the obstacle 4 and return as a reflected signal (hereinafter referred to as "reflector width time") a receiving circuit 200 that outputs the signal as an electrical time difference signal, a stepping motor drive circuit 7 that outputs a driving signal necessary for driving the stepping motor 5 that rotationally scans the transmitting/receiving sensor 2 to the stepping motor 5; Microcomputer unit 3 that outputs calculations and control signals necessary for system A
00, and a display unit controller 400 for displaying the outline of the obstacle 4 closest to the rear end of the vehicle 1 as visual dot information on the display unit 8 as described later. . Here, the transmitting circuit 100 includes a gate circuit 102 at a subsequent stage of a transmitting circuit lot configured to connect two stages of astable multivibrators (not shown) to generate a pulse signal e of a predetermined frequency (for example, 40 kHz).
A trigger pulse signal a having a predetermined @(for example, 300) tS) is sent intermittently from the microcomputer unit 300 to this gate circuit 102, and the gate circuit 102 outputs a pulse signal f. let The intermittent pulse signal f thus output is amplified to a predetermined level by the amplifier circuit 103, and a pulse signal with a sharp rise is output from the transmission/reception sensor drive circuit 104 at the subsequent stage.

As shown in FIGS. 3 and 4, the transmitting/receiving sensor 2 has a configuration in which a transmitter 21 and a receiver 22 having the same characteristics are arranged as a pair. In order to make the emitted ultrasonic pulse into a beam wave with sharp directionality, an acoustic lens 21a is attached to narrow down the diffusion of the ultrasonic wave, and from the above-mentioned transmitting circuit lOO, a sharp pulse signal with a sharp double direction is emitted. is sent and excited to intermittently generate ultrasonic pulses as exploration signals.

The receiving circuit 200 includes an amplification/detection circuit 201 that amplifies and detects the reflected signal of the ultrasonic pulse converted into an electric signal by the wave receiver 22 to a predetermined level, and a waveform that shapes the amplified and detected signal into a rectangular wave. It is configured by combining a shaping circuit 202 and a time difference detection circuit 203 which receives the rectangular wave signal output from the waveform shaping circuit 202 and detects the reflector width time of the ultrasonic pulse as a time difference signal. Here, the 1-time difference detection circuit 203 is constituted by a known RS flip-flop or the like, and its operation is as follows.

As shown in FIG. 5, the trigger pulse signal a output from the microcomputer 300 for emitting ultrasonic pulses from the transmitting/receiving sensor 2 is set every time the trigger pulse signal a is input, and every time one reflected signal is received, that is, Receiver 2 of transmitting/receiving sensor 2
2, and is reset each time a rectangularly shaped signal is input from the waveform shaping circuit 202. Therefore, the time difference between these two signals is the Q output pulse c-1 output from the flip-flop. The pulse width T is detected. Further, a type circuit 204 is added to this time difference detection circuit 203, and this timer circuit 20
4 outputs the reset signal d after a predetermined time has elapsed since the trigger pulse signal a was sent.
Even if the reflected signal is not received, the time difference detection circuit 2
03 is reset and a pulse signal like d-1 is output.

Microcomputer Units) 300 Ha, CPU3
01, a memory 302, and an interface 303. Calculations necessary for control and necessary control signals are transmitted via the interface 303 to the transmitting circuit 100, receiving circuit 200, stepping motor drive circuit 7, It is sent to the display unit controller 400.

Next, the operation of the exploration system will be explained with reference to the flowchart shown in FIG.

When control system A receives the command signal, step 100
At 0, initialization is performed.

- Initialization returns all the counters and flip-flops in systems 1 and A to their initial states, and system A is forcibly returned to a state in which control can be started. Further, at this time, a pulse for returning to the origin is applied to the stepping motor 5, and the transmitting/receiving sensor 2 returns to the origin. In other words, the transmitting/receiving sensor 2 is initialized so as to be oriented in the direction B in FIG. In addition, in this embodiment, the number of pulses is always constant, and the number of pulses is 1; The return to origin is completed by locking with a mechanical stopper (not shown).

Next, in step fool, the microcomputer 3
The trigger pulse signal a is output from 00, and the transmitting/receiving sensor 2
Ultrasonic pulses are emitted from the transmitter 21 of. and,
In step 1002, it is determined whether or not a reflected signal has been received, and if the reflected signal has been received, step 1
If not, the process proceeds to step 1003, where it is determined whether a period of time (for example, 13 m5) has elapsed since the ultrasonic wave was emitted. Here, the time t determined in step 1003 corresponds to the set time of the timer circuit 204 described above, that is, the maximum value of the searchable range (indicated by diagonal lines), and the time t that is determined in step 1003 corresponds to the maximum value of the searchable range (indicated by diagonal lines). However, if no reflected signal is detected, it is determined that there is no obstacle within the search range, and the process proceeds to step 1009, where the drive circuit 7 of the stepping motor 5 is energized to move the stepping motor 5 one step at a time. In step 100-1-4-, one reflector width time of ultrasonic waves is read. This transmission time means the time required for the ultrasonic pulse emitted from the transmission/reception sensor 2 to hit the obstacle 4 and bounce back. In step 1005, which is detected by outputting the pulse signal c-1 of T, the rotation angle of the transmission/reception sensor 2 is read. This is done by counting numbers. Next, in Step 2 1006, based on the read reflection propagation time and the rotation angle of the transmitting/receiving sensor 2, it is determined how far away the outline of the obstacle 4 is in a straight line from the rear end line of the vehicle. Furthermore, the position of the obstacle 4 is converted into two-dimensional information according to the display section 8 as shown in FIG. This conversion is performed by comparing the calculated position of the obstacle 4 to which dot arranged in a grid on the 1 display section 8, and from the -aspect of the compared dot. Obstacle 4
The closest one is selected as the location information of the obstacle 4. In step 1007, step 100
The position information of the obstacle 4 selected in step 6 is stored in the memory, and the process proceeds to step 1008, where it is determined whether the transmitting/receiving sensor 2 is at the terminal position. The end position here means the end point of scanning of the transmitting/receiving sensor 2. For example, when the transmitting/receiving sensor 2 moves back and forth between points B and C as shown in FIG. This corresponds to a point. As a result of the determination in step 1008, if the transmitting/receiving sensor 2 is at the terminal position, the process advances to step 1010 to read out the loaded two-dimensional information. step forward,
It returns to step 1001 and emits an ultrasonic pulse. Here, the stepping of the stamping motor 5 is performed by sending a drive signal from the microcomputer unit 300 to the stamping motor drive circuit 7, and the stepping motor 5 is stepped in the forward or reverse direction depending on the rotation angle of the transmitting/receiving sensor 2. . step,
At step 1010, when the loaded two-dimensional information is read from the memory, in the next step toll it is determined whether or not an obstacle 4 exists within 2 m from the rear end of the vehicle. That is, this determination is made in step 1010.
This is done by detecting the minimum value from the read information when the two-dimensional information is read out, and if the minimum value is 2 m or less when converted into a straight line distance from the rear end of the vehicle, proceed to step 10121. Two-dimensional information corresponding to the outline of the obstacle 4 is displayed on the display section 8. This display is made by displaying a plurality of LEDs 8 as shown in FIG.
1 are arranged in a square shape, this is done by lighting up the LED 8 La corresponding to the outline of the obstacle 4 closest to the vehicle, as shown by the black circle in FIG. In addition, in this case, the LED 81 of the contour part
It is also possible to light up not only LE081b but also all LE081b existing inside it. On the other hand, step 101
1, if it is determined that the closest contour of the obstacle 4 is located at a distance of more than 2 m in straight line distance from the rear end of the vehicle, the process proceeds to step 1014, where the 1 display section 8
It is displayed that there is no obstacle 4 within the vicinity of . This display consists of LEDs 8 arranged in 1 display section 8.
This may be carried out by lighting up 1 and displaying a predetermined symbol, but it is also possible to display a predetermined symbol by lighting it in a part of the 1 display section 8 where the LEDs are not arranged.
This operation is repeated until the main switch for exploration is turned off.

In this way, the transmitting/receiving sensor 2 receives the control signal from the microcomputer unit 300, intermittently emits ultrasonic pulses as exploration signals, continues the scanning movement while receiving the emitted ultrasonic signals, The outline of the obstacle 4 existing within a close range is displayed on the display section 8 as don't information. Therefore, the driver can
By observing this, it is possible to know the approach of the obstacle 4, and to drive safely.

In the embodiment, an example in which an ultrasonic pulse is used as a probe signal is explained. However, the device of the present invention is not limited to such an example. It may also be possible to search for obstacles.

In addition, as for the scanning movement of the transmission/reception sensor 2, although only the oscillating movement was shown in the embodiment, it goes without saying that a rotational movement may also be used, and the mounting position may be at a corner. Ba.

It may be in front of the vehicle 1.

Furthermore, as shown in FIG. 10, the range that can be searched by the transmitting/receiving sensor 2 may be limited to a small distance of about In on the side of the vehicle l compared to other sides, for example, the rear side. In such a case, the maximum value of the reflective report time can be shortened on the side of the vehicle 1 (indicated by diagonal lines), so there is an advantage that necessary information can be quickly displayed on the display section 8.

As explained above, according to the vehicle obstacle search device of the present invention, in order to search for obstacles close to the vehicle, a directional search signal is intermittently transmitted, and the transmitted Since the transmitting/receiving sensor is installed at the corner of the vehicle, which performs a scanning motion while receiving the reflected signal that comes back when the signal hits an obstacle, the sensor is installed at the center of the rear of the vehicle. It has the advantage that the exploration range can be expanded to a wide angle of nearly 270 degrees.

[Brief explanation of drawings]

Fig. 1 is a plan view of the drawing to which the device of the present invention is applied, Fig. 2 is a perspective view of the main parts of the vehicle shown in Fig. 1 seen from the rear to show the installation status of the transmission/reception sensor, and Fig. 3 is FIG. 4 is a perspective view showing the transmitting and receiving sensor, FIG. 4 is a pronk diagram showing the schematic configuration of the exploration system, FIG. 5 is a waveform diagram explaining the operation of the time difference detection circuit, and FIG. 6 is used to implement the exploration system. FIG. 7 is a flowchart of the control program, FIG. 7 is a diagram showing the specific configuration of the display section, and FIG. 8 is a diagram showing an example in which the range that can be searched by the transmitting/receiving sensor is particularly limited on the side of the vehicle. 1st - Vehicle lb... - Corner part 2... Transmission/reception sensor 3... Scanning movement mechanism 4... Obstacle agent Patent attorney Hiroshi Akazawa Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 8

Claims (2)

[Claims] (1) In order to search for obstacles close to the vehicle, a directional search signal is intermittently transmitted, and the transmitted signal hits the obstacle and scans while receiving the reflected signal that returns. An obstacle detection device for a vehicle, characterized in that a transmitting/receiving sensor that moves is provided at a corner of the vehicle. (2) An obstacle search device for a vehicle, characterized in that the range that can be searched by the transmitting and receiving sensor is limited to a certain distance on one side of the vehicle, which is smaller than on other sides.