JPS61243384A - Alarm system for ultrasonic sonar - Google Patents

Abstract

PURPOSE:To enable simple recognition of the type of a obstacle, by a method wherein a comparison level, is automatically set according to the reflection time of an echo wave and an obstacle is discriminated by comparing the reception level of the echo wave with the comparison level to emit a voice alarm. CONSTITUTION:An ultrasonic wave which is reflected on an obstacle after being emitted from a transmission sensor 5a of an ultrasonic unit 5 is received with a reception sensor 5b to be introduced to a programable gain amplifier 13. The PGA13 changes the gain according to the reflection time of the ultrasonic wave to compensate for attenuation and the received signal is introduced into a computer 2 through a PPH14 and an A/D converter 15. As the reflected ultrasonic wave changes in the reception level with the obstacle, the reception level and the reflection time of the reflected wave are compared with an internal table within the computer 2 to discriminate the presence, type and the position of the obstacle and a voice alarm is emitted from a speaker 22.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to an ultrasonic sonar VI reporting system, and more specifically, to distinguish the type of obstacle detected by an ultrasonic sonar mounted on a car or the like. This relates to a system that issues an audible warning.

"Prior Art and its Problems" Conventionally, an automatic ultrasonic sonar as disclosed in, for example, Japanese Unexamined Patent Publication No. 57-84377 has been proposed. This uses ultrasonic waves to detect the presence and location of obstacles around the vehicle.

That is, when ultrasonic waves are emitted in a pulsed manner from the car side, if there is an obstacle in that direction, the ultrasonic waves are reflected and echo waves are received. Therefore, the presence or absence of an obstacle and the distance to it are detected based on the presence or absence of this echo wave and the time it takes for it to be reflected (reflection time).

However, a problem with such conventional ultrasonic sonar is that it is not possible to know the type of obstacle.

``Object of the Invention'' The present invention aims to provide an ultrasonic sonar warning system that, when an obstacle is detected by an ultrasonic sonar, allows the type of the detected obstacle to be known by an audio warning. purpose.

``Configuration of the Invention'' The ultrasonic sonar alarm system of the present invention includes an ultrasonic sonar mounted on a vehicle that detects obstacles outside the vehicle, and a comparison level that is determined according to the reflection time of echo waves received by the ultrasonic sonar. Comparison level setting means for automatically setting, comparison means for comparing the comparison level with the reception level of the echo wave, and an audio warning for determining the type of obstacle based on the comparison result and outputting an audio signal corresponding to the type. It is characterized in that it is provided with means.

"Effect" It is known that the reception level of echo waves in ultrasonic sonar is determined by the distance to an obstacle. In other words, the greater the distance to the obstacle, the lower the reception level. This is because energy attenuates depending on the distance it travels through the air.

However, as a result of two studies, the inventor of the present invention found that the reception level of echo waves changes not only depending on the distance to the obstacle but also on the type of the obstacle. According to this,
Even if the distance is constant, the reception level increases when the obstacle is a wall.

The reception level decreases in the order of humans and bicycles.

Therefore, if you know both the distance to the obstacle and the reception level of the echo wave, you can determine the type of obstacle.

"Example" The present invention will be described in more detail below based on the example shown in the drawings. FIG. 1 is a block diagram of the configuration of an ultrasonic sonar warning system according to an embodiment of the present invention, FIG. 2 is a perspective view of an ultrasonic sonar installed on the rear bumper of an automobile, and FIG. 3 is a block diagram of an ultrasonic sonar warning system according to an embodiment of the present invention. FIG. 3 is a characteristic diagram of type, distance, and reception level of echo waves. Note that the present invention is not limited to this example.

As shown in Figure 1, this ultrasonic sonar's W7 is a warning system! is built into a scanning type ultrasonic sonar in which a computer 2 drives a stepping motor 4 via a driver 3 to rotate an ultrasonic unit 5.

The ultrasonic unit 5 includes a transmitting sensor 5□ and a receiving sensor 5.
1. are located adjacent to each other.

The 40 KHz carrier wave generated by the fundamental wave generation circuit 6 becomes a pulse wave by the computer 2 opening the AND gate 7 in a 300 μs pulse shape, and is input to the transmitting sensor 5m via the amplifier circuit 8 and the output circuit 9. . As a result, the transmitting sensor 511 transmits a pulsed ultrasonic wave of 40 KHz.

The ultrasonic waves emitted in a pulsed manner are reflected by external obstacles and return echo waves, which are detected by the receiving sensor 5b.
Amplification circuit 10. Filter 11. Detection circuit 12. Programmable gain amplifier 13. A digital value is input to the computer 2 via the programmable peak hold circuit 14 and the AD converter 15.

The reason for using the programmable gain amplifier 13 is
This is because the further away the obstacle is, the greater the attenuation of the echo wave and the harder it becomes to detect, so to compensate for this, the gain is increased as time passes.

The computer 2 determines the reflection time based on the time from when the AND gate 7 is opened and the ultrasonic wave is emitted in a pulsed manner to when the AD converter j5 obtains an output of a predetermined value or more and recognizes that an echo wave has been detected. Determine the presence and location of obstacles.

In other words, if the echo wave is detected within a predetermined time, the obstacle is at a distance proportional to the reflection time until it is detected, and if the echo wave is not detected after the predetermined time, it is determined that there is no obstacle. do.

As shown in FIG. 2, the ultrasonic unit 5 is provided at the left end of the rear bumper B of the automobile A, and is rotated together with a rotary table 24 in a horizontal plane by the stepping motor 4. Therefore, the combiator 2 determines the rotation position of the ultrasonic unit 5, that is, the search direction, from the rotation angle of the stepping motor 4.

As a result, the computer 2 can detect the presence or absence of an obstacle and its position (direction, distance M).

This results in decoders 16.17 and drivers 18.
Via 19, it is displayed on an LED matrix 20.

Further, the computer 2 determines the type of obstacle based on the magnitude of the reception level of the echo wave, and determines the type of the obstacle by using the onomatopoeic sound generation circuit 2.
1, and is output as an onomatopoeic sound by the speaker 22.

That is, the computer 2 internally has a table of distances to obstacles and comparison levels corresponding thereto.

For example, if the characteristics of the type of obstacle, the distance, and the echo wave reception level are as shown in Figure 3, this comparison level is 20 mV at a distance of 25 cm to 341 cm, and 20 mV at a distance of 35 cm.
~44al is 13mV, distance 45c11~54c1
1, 8 mV is input in advance, and distance 55 cm to 64 cm is input as 5 mV.

The computer 2 calculates the distance from the reflection time of the echo wave, and selects a comparison level according to the calculated distance. Also AD
The output value of the converter 15 is divided by the gain of the programmable gain amplifier 13 or the like to calculate the original echo wave reception level.

Next, the comparison level and the echo wave reception level are compared, and if the latter is larger than the former, if the "wall-shaped" obstacle is 1 smaller, then the fi type is determined as "Other, j obstacle".

When the obstacle is determined to be a "wall-shaped" obstacle, an onomatopoeic sound "like knocking on a wall" is generated, for example, and when the obstacle is determined to be "other", an onomatopoeic sound "similar to a human voice" is generated.

Note that when the distance is 24 cm or less and when it is 65 cm or more, the type of obstacle is not determined and an "electronic sound" is generated automatically. Furthermore, even when it is determined that the position of an obstacle is to the side of the vehicle, the type of the obstacle is not determined, and an onomatopoeic sound such as "the engine sound of a bite machine" is generated.

In this way, the driver can determine the existence and location of an obstacle by the blinking state of the LED matrix 20, and can also get an idea of what the obstacle is by the onomatopoeia generated from the speaker 22.

As examples of Haku, the comparison level is calculated from an arithmetic expression instead of using a table, the comparison level is calculated directly from the echo wave reflection time without calculating the distance, and the gain is calculated in advance. One is to set the comparison l/bel multiplied by , and then directly compare it with the output value of the AD converter 15, and the other is to set multiple comparison levels corresponding to the same distance in two stages: "wall-like" and "other". Instead of “wall-like” and “
An example is one that performs multi-level discrimination such as ``car'', ``person-1'', and ``other''.

"Effects of the Invention" According to the present invention, an ultrasonic sonar mounted on a vehicle detects obstacles outside the vehicle, and a comparison level is automatically set according to the reflection time of an echo wave received by the ultrasonic sonar. The apparatus includes a level setting means, a comparison means for comparing the comparison level with the reception level of the echo wave, and an audio warning means for determining the type of obstacle based on the comparison result and outputting an audio signal corresponding to the type. An ultrasonic sonar W-warning system is provided, which is characterized by the ability to detect obstacles.This system allows not only the presence and location of obstacles but also the type of obstacles to be known through audio HH, which is a great way to alert drivers. This improves power and contributes to safe operation of automobiles.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the configuration of an ultrasonic sonar warning system according to an embodiment of the present invention, Fig. 2 is a perspective view of the ultrasonic sonar attached to the rear bumper of an automobile, and Fig. 3 shows the types of obstacles and FIG. 3 is a characteristic diagram of distance and echo wave reception level. (Explanation of symbols) l...Ultrasonic sonar 2...Computer 4...Stepping motor 5...Ultrasonic unit 20...LED matrix 21...Onomatopoeia generating circuit 22...Speaker 24... ...Rotary table A...Car B...Rear bumper.

Claims (1)

[Claims] 1. An ultrasonic sonar mounted on a vehicle that detects obstacles outside the vehicle, a comparison level setting means that automatically sets a comparison level according to the reflection time of an echo wave received by the ultrasonic sonar, and a comparison level and the echo. An ultrasonic sonar characterized by comprising a comparison means for comparing the received level of waves and an audio warning means for determining the type of obstacle based on the comparison result and outputting an audio signal corresponding to the type of obstacle. alarm system.