JPH0333675A - Ultrasonic converter, ultrasonic detector, movable body equipped with the two and ultrasonic detection - Google Patents

Abstract

PURPOSE:To increase the sensitivity of reception and also to improve the reliability in respect to a short circuit by connecting ultrasonic converters in each ultrasonic converter group in series and by connecting the converter groups in parallel. CONSTITUTION:An ultrasonic reception apparatus 10 comprises three ultrasonic converter groups 7, 8 and 9 connected in parallel to one another and a reception impedance 11, and the converter groups 7, 8 and 9 comprise two identical ultrasonic converters 1 - 2, 3 - 4 and 5 - 6 connected in series, respectively. In this constitution, a voltage obtained when the converters in the converter groups 7, 8 and 9 are connected in series is about twice as large as the one obtained when they are connected in parallel, and the sensitivity of reception is increased. A voltage applied on the converters 1 to 6 is a half of the voltage impressed on the apparatus 10, and therefore the level of the voltage impressed thereon can be increased. Moreover, even when the converter 1 in the converter group 7, for instance, is short-circuited, the voltage impressed on the apparatus 1 does not become zero unless the other converter 2 is short-circuited, and thus the reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ultrasonic transducer, an ultrasonic detector, a mobile body equipped with these, and an ultrasonic detection method using a plurality of ultrasonic waves 1 to a lance ducer. .

[Prior Art] As a conventional ultrasonic wave transmitting/receiving device, there is, for example, one shown in the schematic layout and layout diagram of FIG. 12 and the circuit diagram of FIG. 13.

In other words, it consists of an array sensor or a plurality (n) of identical transducers connected in parallel (12th
See figure.

[Problems to be Solved by the Invention] In such a conventional ultrasonic transducer, the impedance of the ultrasonic transducer is 2, the output voltage when receiving ultrasonic waves is V, and the input of the ultrasonic receiver and receiver is Impedance 2.
If the sound pressure voltage conversion ratio of the 81 sonic transducer is α, and the sound pressure received by the ultrasonic transducer is P1 to Pn (see Figure 13), then V = (P, +l)
2+P3+・+pn)n+.

However, this conventional ultrasonic transducer still has a problem in that the output voltage is not large enough because the receiving sensitivity of each ultrasonic transducer is low.

On the other hand, it is conceivable to connect the transducers in series. However, in this case, there is a drawback that if one of them becomes short-circuited, it becomes impossible to transmit or receive ultrasonic waves.

The present invention has been made by focusing on the problems of the conventional technology, and is an ultrasonic wave that has high reception sensitivity and can transmit and receive waves even if some transducers are short-circuited. The present invention aims to provide a wave transmitting device, an ultrasonic wave transmitting/receiving device, an ultrasonic detection device, a mobile body equipped with these, and an ultrasonic detection method.

[Means for Solving the Problems 1] In order to achieve this objective, the ultrasonic transducer device for transmitting and/or receiving ultrasonic waves according to the first invention of Muyi is:
It is constructed by connecting in parallel a plurality of ultrasonic transducer groups each having a plurality of ultrasonic transducers connected in series.

Further, the ultrasonic transducer for transmitting and/or receiving ultrasonic waves according to the second invention of the present application is one of an ultrasonic transducer group in which a plurality of ultrasonic transducers are connected in series.
It is characterized in that it consists of a group or groups and one or more single ultrasonic transducers connected in parallel.

Note that the ultrasonic converter includes an ultrasonic transmitter, an ultrasonic receiver, and an ultrasonic transmitter/receiver.

Further, in the ultrasonic transducer for transmitting ultrasonic waves according to the third invention of the present application, ultrasonic transducer groups in which a plurality of ultrasonic transducers are connected in series are arranged on both sides, and between them, one or more groups of ultrasonic transducers in which a smaller number of ultrasonic transducers than the plurality of ultrasonic transducers are connected in series; and/or
It is characterized in that one or more single ultrasonic transducers are connected in parallel.

Further, in the ultrasonic transducer for receiving ultrasonic waves according to the fourth invention of the present application, the plurality of ultrasonic transducers are arranged on both sides of an ultrasonic transducer group in which the plurality of ultrasonic transducers are connected in series. one or more groups of ultrasonic transducers connected in series with fewer ultrasonic transducers than users; and/or one or more of a single ultrasonic transducer connected in parallel. It is characterized by consisting of:

The ultrasonic transducers may be arranged in one or two rows.

The ultrasound transducers may be arranged in two rows, and the ultrasound transmission direction of one row may be different from the ultrasound transmission direction of the other row.

An ultrasonic detection device according to a fifth invention of the present application includes the above-mentioned ultrasonic converter, a time difference detection circuit that measures the round trip time of ultrasonic waves, and, when the output of the time difference detection circuit is smaller than a predetermined reference value, The present invention is characterized by comprising: a comparator that outputs a detection signal;

The ultrasonic detection device may include a warning device (tuser) that issues an alarm upon receiving the detection signal.

Furthermore, the vehicle may include a stop circuit that automatically operates the brake to stop the work vehicle when the detection signal is input.

A mobile object or a working vehicle according to a sixth aspect of the present invention is characterized in that the above-mentioned ultrasonic transducer is attached to the front and/or the rear.

A mobile object or work vehicle according to a seventh aspect of the present invention is characterized by having the above-mentioned ultrasonic detection device.

The ultrasonic detection method of the eighth invention of the present application has an ultrasonic transducer group divided into at least three groups, one on both outer sides and a central part, and ultrasonic waves are transmitted from the two outer ultrasonic transducers. transmitting ultrasonic waves stronger in intensity than sound waves from the central ultrasonic transducer, and receiving ultrasonic waves returned from the object by the ultrasonic transducers of the ultrasonic transducer group; The distance to the object is determined by measuring the round trip time of the ultrasonic waves, and when the distance is within a predetermined distance,
It is characterized by outputting a detection signal of the object.

The ultrasonic detection method of the ninth invention of the present application has an ultrasonic transducer group divided into at least three parts, one on both outer sides and a central part, and ultrasonic A sound wave is transmitted, and the ultrasonic wave returned from the object is received by the central ultrasonic transducer with higher sensitivity than the outer ultrasonic transducers, and the round trip time of the ultrasonic wave is measured. The device is characterized in that it calculates the distance to the object, and outputs a detection signal of the object when the distance is within a predetermined distance.

In the above invention, a mobile object refers to any mobile object such as a work vehicle such as a rotor roller or a power shovel used for road construction, a work robot, an automatic guided vehicle, a guide robot for the blind, or a vehicle such as a truck or a luxury car. It includes. Further, the vehicle to which the above invention is applied may have rails, and may also float and move.

The ultrasonic transducer of the present invention is suitably applied as an array sensor.

Furthermore, the ultrasonic transducer, ultrasonic transceiver, ultrasonic detection device, mobile object equipped with these devices, and ultrasonic detection method of the present invention can be incorporated into a transportation system.

Furthermore, in the present invention, objects include objects such as obstacles and objects for work or movement, as well as all objects that reflect ultrasonic waves, such as humans, animals, plants, and the like. Further, the object may be an object that simply reflects ultrasonic waves, or may have a transponder.

[Effect 1] Since the ultrasonic transducer or the ultrasonic detection device has transducers connected in series in each ultrasonic transducer group, the receiving sensitivity is higher than that of the device 1 which is only connected in parallel.

In addition, since the ultrasonic transducers are connected in parallel, even if some transducers short, other transducers can still transmit and receive ultrasonic waves, increasing the reliability of the device. Ii+1''.

1 Example 1 Various examples of the present invention will be described below based on the drawings. Incidentally, the same types of parts in various embodiments are given the same reference numerals and redundant explanations will be omitted.

1 to 5 show a first embodiment of the present invention.

As shown in FIGS. 1 and 2, an ultrasonic transceiver 1
0 from the three first, second and third ultrasonic transducer groups 7.8.9 and the receiving impedance 11 connected in parallel with each other.

The ultrasonic transducer group 7 derives from two identical ultrasonic transducers 1.2 connected in series, and the ultrasonic transducer group 8 likewise derives from two identical ultrasonic transducers 1.2. The ultrasonic transducer group 9 consists of users 3 and 4, and the ultrasonic transducer group 9 includes the ultrasonic transducer 5.
．． I have been admonishing this since 6.

FIG. 3 is an enlarged perspective view of the ultrasonic wave transmitting/receiving device.

The ultrasonic transducers 1, 2, 3, 4, 5゜6 have, for example, a horizontal length a of 120 mm and a vertical length b of 60 mm.
It consists of a box with a depth C of 140 mm.

A quadrangular pyramid-shaped horn 13 is provided in the opening with its bottom portion as the opening. The horn 13 is made of styrofoam. The opening of each transducer 2 coincides with the opening of the horn 13.

An ultrasonic sensor 14 is arranged on the top side of the horn 13. The ultrasonic sensor 14 is provided on the wall facing the opening. The ultrasonic sensor 14 has a diameter of 25 mm.
This is a piezoelectric sensor.

As illustrated in FIG.
．． 2, 3, 4, 5.6 are installed in one row in the horizontal direction. Further, the ultrasonic wave transceiver lO is also attached to the rear of the work vehicle 21.

FIG. 5 is a block diagram of a circuit of an ultrasonic detection device using the ultrasonic transceiver 10 described above.

On the transmitting side, the main synchronization circuit 44 sequentially connects the pulse generator 43
, modulator 42, power amplifier 41, ultrasonic transceiver 10
It is connected to the. Modulator 42 is also connected to oscillator 45 .

On the other hand, on the receiving side, the ultrasonic transceiver 10 includes a receiving impedance 11, a large signal remover 51, a receiving amplifier 52, a signal comparator 53, a time gate generator (time difference detection circuit) 54, and a modulator 55. , a counter 57, a time difference determiner (comparison circuit) 58, a pulse generator 59, and a buzzer 60.

The modulator 55 also includes a timekeeping clock pulse oscillator 56.
is also connected. Timing gate generator 54 is also connected to pulse generator 43 .

Next, the action will be explained.

The impedance of the ultrasonic transducer is 2, the output voltage when receiving ultrasonic waves is V, the input impedance of the ultrasonic receiver is Z, the ultrasonic wave 1 - the sound pressure voltage conversion ratio of the transducer is α, the ultrasonic transformer The sound pressure received by the ducer is P1
~Pn, and assuming that the current flowing through the ultrasonic transducer group 7, 8.9 is '+ + "2+ 1:+ (see FIG. 2), ■-αP, +αP2-2zi.

=(!P3+(XP4-2zi2 =αP5+αP6-2zi:+ Therefore, α V = (P 1+ P 2 + P 3+ P
< + P 5 + P 6)-z (i,
+ i 2 + i 3 ) Furthermore, 5 v −-(p.

+p2 +P3 +P4 +P5 +P6) zV Z Therefore, Z becomes.

On the other hand, in the conventional example, under the condition of Z)z, the voltage V' when all six ultrasonic transducers are connected in parallel is α V '' = (PI+
P2"P3"P4"PS+P6)6+□.

In this way, the ultrasonic wave transmitting/receiving device 10 of this embodiment can obtain a voltage approximately twice as large as that of the conventional example without using a transformer.

In addition, since the voltage applied to each ultrasonic transducer 1, 2, 3゜6 4.5.6 is half the voltage applied to the ultrasonic transducer 10, the voltage level applied to the device 10 is You can make it bigger.

Further, for example, even if one ultrasonic transducer 1 of the first ultrasonic transducer group 7 is shorted, the voltage will not be applied to the device 10 unless another ultrasonic transducer 2 is shorted. The voltage V never becomes zero, which improves the reliability of the device.

In FIG. 5, from the main synchronous circuit 44 to the pulse generator 43
The pulse generator 43 outputs a clock signal to the modulator 42, and the pulse generator 43 outputs a synchronized pulse signal to the modulator 42.

The oscillator 45 outputs continuous wave excitation pulses to the modulator 42 . Thereby, the modulator 42 outputs the burst pulse to the power amplifier 41.

The power amplifier 41 amplifies this pulse and applies it to the ultrasonic transceiver IO.

In the ultrasonic transducer IO, all transducers 1, 2, 3, 4, 5.6 are driven in the same phase and transmit ultrasonic waves simultaneously.

After the ultrasonic waves are returned from the object, the ultrasonic wave transmitter/receiver l
Received by O.

Objects to be detected include objects that reflect ultrasonic waves, as well as 1-
It may also have a lance bonder.

The received ultrasonic waves are input to a large signal remover (limiter) 51 and then input to a signal comparator 53 via a reception amplifier 52.

The signal comparator 53 detects the signal from the receiving amplifier 52 and outputs a pulse for the time when a signal having an amplitude exceeding a threshold level is input. Pulses from signal comparator 53 are input to warm gate generator 54 .

The temperature gate generator 54 functions as a time difference detection circuit that measures the round trip time of the ultrasonic waves. That is, the temperature gate generator 54 generates a pulse after the pulse generator 43 outputs a pulse for driving the ultrasonic transceiver 10 until the signal comparator 53 outputs a received signal. is output to the modulator 55. This 111 force period is compatible with the e1 return time of the eaves sound wave.

The output from the modulator 55 is input to a time difference determiner 58 via a counter 57.

The time difference determiner 58 functions as a comparison circuit, turns on when the value of the counter 57 is within a predetermined value, and outputs a signal to the pulse generator 59.

Pulse generator 59 activates fuser 60.

Thereby, the buzzer 60 issues an alarm to notify that an object within the reference distance of the near field 32 has been detected.

FIG. 6 shows a second embodiment of the invention.

In this embodiment, the ultrasonic transducer 10 includes two ultrasonic transducer groups 71 and 72 connected in parallel to each other.
and receiving impedance 11.

The ultrasonic transmitting/receiving device 10 is attached to the front part of a road roller work vehicle so that ultrasonic transducers 1, 2, 3° 9 4, 5, 6 are arranged in one row in the horizontal direction.

The ultrasonic transducer group 71 includes three
The ultrasonic transducer group 72 is similarly connected to three identical transducers 4, 5.6.

In this embodiment, the output voltage V when receiving ultrasonic waves is α Z becomes.

FIG. 7 shows a third embodiment of the invention.

In this embodiment, the ultrasonic transducer lO includes six ultrasonic transducer groups 81 and 82 connected in parallel to each other.
, 83, 84, 85.86 and receiving impedance 1
It consists of 1.

Ultrasonic transducer group 81, 82, 83° 84.8
5.86 consists of two identical ultrasonic transducers connected in series.

The ultrasonic transducer group 81, 83, 84°86 is -
Ultrasonic transducer group 82.8
5 is attached to the lower row.

Ultrasonic transducer 1, 2, 3, 4, 5゜6.87
．． The ultrasonic transducers 88 are arranged in one upper row in the horizontal direction, and the ultrasonic transducers 89, 90, 96, and 97 are arranged in one lower row in the horizontal direction.

A total of four ultrasonic transducers 89,90°96.97 in the lower row ultrasonic transducer group 82.85 are the same as the upper row ultrasonic transducer group 81.83, 84.86.
A total of 8 ultrasonic transducers 1, 2, 3, 4, 5
, 6, 87.88, and is oriented downward at an angle of 45 degrees.

Therefore, in this embodiment, it is possible to eliminate detection failure at short distances.

In this example, the output voltage V when receiving ultrasonic waves is Z becomes.

FIG. 8 shows a fourth embodiment of the invention.

In this embodiment, the ultrasonic transducer 10 includes five ultrasonic transducer groups 91 and 92 connected in parallel to each other.
．． 93, 94.95 and the receiving impedance 11.

The ultrasonic transducer groups 91 and 95 consist of three ultrasonic transducers connected in series and are arranged on both sides, but the ultrasonic transducer groups 92 and 93
．． 94 is a J ultrasonic transducer group 91.95 consisting of two identical transducers connected in series.
is located between.

The ultrasonic wave transmitting/receiving devices 10 are arranged in two rows, one above the other and the transducers. one ultrasonic transducer in each of the ultrasonic transducer groups 91.95 and ultrasonic transducer groups 92, 93.94;
are installed in one upper row in the horizontal direction, and the remaining two ultrasonic transducers of the ultrasonic transducer groups 91 and 95 are installed in one lower row in the horizontal direction.

In this embodiment, the output voltage V when receiving ultrasonic waves is α Z becomes.

FIG. 11 is a graph showing the relative sound pressure with respect to the distance of the ultrasonic wave on the central axis produced by the ultrasonic wave transmitting/receiving device of this embodiment.

In this embodiment, the ultrasonic transmission level at the center of the upper row of the ultrasonic wave transceiver 10 is higher than the transmission level from both sides of the upper row 1 and from the lower row.

In this embodiment, it is possible to eliminate zero points at short distances.

FIG. 9 shows a fifth embodiment of the present invention. 3 Ru.

In this embodiment, the ultrasonic transducer 1O has ultrasonic transducer groups 73 and 74, which are two ultrasonic transducers connected in series, arranged on both sides.
The ultrasonic transducer 3 and 4 are connected in parallel.

The ultrasonic transducer IO is installed in the front part of the road roller working area so that ultrasonic transducers 1, 2, and 3°4.5.6 are arranged in one row in the horizontal direction.

In this embodiment, the ultrasonic transmission level at the center of the ultrasonic transceiver IO is higher than the transmission level from both sides thereof.

Ultrasonic transducers 1 and 2 of the ultrasonic transducer 10
, 3, 4, 5.6 are arranged in one or two rows horizontally at the front of the road roller work vehicle 21, or vertically or diagonally depending on the application. , may be arranged in one or two columns, or may be arranged in two or more columns.

4 Although the above-mentioned embodiment shows an example of an ultrasonic wave transmitting/receiving device, the present invention may be applied to a wave transmitting device or a wave receiving device.

FIG. 12 shows a sixth embodiment of the invention.

In this embodiment, the ultrasonic transducer IO includes two ultrasonic transducers 1.6 on both sides of an ultrasonic transducer group 75 and 76, which are two ultrasonic transducers connected in series. are arranged and connected in parallel.

The ultrasonic transducer 10 is attached to the front of a road roller work vehicle so that ultrasonic transducers 1, 2, and 3 are arranged in one row in the horizontal direction.

In this embodiment, the ultrasonic reception sensitivity at the center of the ultrasonic wave transmitting/receiving device 10 is greater than the reception sensitivity at both sides thereof.

If the fifth embodiment shown in FIG. 9 is used exclusively as an ultrasonic transmitter, and the sixth embodiment shown in FIG. 12 is exclusively used as an ultrasonic receiver, the The ultrasound transmission level can be made higher than the transmission level from both sides, and the ultrasound reception sensitivity at the center can be made higher than the reception sensitivity at both sides.

With this configuration, objects in the traveling direction of the road roller work vehicle can be detected further away without being overly sensitive to objects protruding from the width of the road roller work vehicle.

[Effects of the Invention] According to the ultrasonic wave transmitting device, the ultrasonic wave transmitting/receiving device, and the ultrasonic detection device according to the present invention, the receiving sensitivity of each ultrasonic transducer can be increased.

Furthermore, even if some transducers are short-circuited, other transducers can still transmit and receive ultrasonic waves, improving the reliability of the device.

[Brief explanation of drawings]

1 to 12 show embodiments of the present invention, FIG. 1 is a schematic layout diagram of the ultrasonic transceiver device of the first embodiment, FIG. 2 is a circuit diagram of the device of FIG. 1, FIG. 3 is an enlarged perspective view of the ultrasonic transceiver device, FIG. 4 is a perspective view of a working vehicle equipped with the ultrasonic transceiver device of the present invention, and FIG. 5 is a block diagram of the circuit of the ultrasonic detection device. FIG. 6 is a schematic layout diagram of the ultrasonic wave transceiver device of the second embodiment, FIG. 7 is a schematic layout diagram of the ultrasonic wave transmitter/receiver device of the third embodiment, and FIG. 8 is a schematic layout diagram of the ultrasonic wave transmitter/receiver device of the fourth embodiment. A schematic layout diagram of the device, FIG. 9 is a schematic layout diagram of the ultrasonic wave transmitting/receiving device of the fifth embodiment, and FIG. graph,
FIG. 11 is a graph showing the relative sound pressure with respect to the distance of ultrasonic waves produced by the ultrasonic transceiver device of the fourth embodiment, and FIG.
A schematic layout diagram of the ultrasonic transceiver device of the embodiment, FIGS. 13 and 14 show a conventional example, FIG. 13 is a schematic layout diagram of the ultrasonic transceiver device of the conventional example, and FIG. FIG. 14 is a circuit diagram of the device of FIG. 13; l, 2. ~12... Ultrasonic transducer 7.8.
9... Ultrasonic transducer group 10... Ultrasonic wave transmitting/receiving device 7 11... Impedance 21... Working vehicle 54... Warm gate generator 58... Time difference determiner 60. ··buzzer

Claims (1)

[Claims] 1. Ultrasonic conversion configured by connecting in parallel a plurality of groups of ultrasonic transducers each having a plurality of ultrasonic transducers connected in series, and transmitting and/or receiving ultrasonic waves. Device. 2. One or more ultrasonic transducer groups in which a plurality of ultrasonic transducers are connected in series, and
one or more single ultrasonic transducers;
Ultrasonic transducer devices connected in parallel to transmit and/or receive ultrasonic waves. 3. A group of ultrasonic transducers in which a plurality of ultrasonic transducers are connected in series are arranged on both sides, and a smaller number of ultrasonic transducers than the plurality of ultrasonic transducers are connected in series between them. An ultrasonic transducer configured by connecting a group or multiple groups and/or one or more single ultrasonic transducers in parallel, and transmitting ultrasonic waves. 4. One or more groups of ultrasonic transducers in which a smaller number of ultrasonic transducers than the plurality of ultrasonic transducers are connected in series on both sides of an ultrasonic transducer group in which a plurality of ultrasonic transducers are connected in series, and/ Or, it is configured by connecting one or more single ultrasonic transducers in parallel,
Ultrasonic converter that receives ultrasonic waves. 5. The ultrasonic transducer according to claim 1, 2, 3 or 4, wherein the ultrasonic transducers are arranged in one or two rows. 6. The ultrasonic transducers are arranged in two rows,
6. The ultrasonic transducer according to claim 1, wherein the ultrasonic wave transmission direction of one row is different from the ultrasonic wave transmission direction of the other row. 7. The ultrasonic transducer according to claim 1, 2, 3, 4, 5 or 6, and a time difference detection circuit for measuring the round trip time of ultrasonic waves, and an output of the time difference detection circuit being smaller than a predetermined reference value. 1. An ultrasonic detection device comprising: a comparator that outputs a detection signal when the detection signal is detected. 8. A movable body or work vehicle having the ultrasonic transducer according to claim 1, 2, 3, 4, 5, or 6 attached to the front and/or rear. 9. A mobile object or work vehicle comprising the ultrasonic detection device according to claim 7. 10. It has an ultrasonic transducer group divided into at least three groups, one on both outer sides and a central part, and transmits ultrasonic waves stronger in intensity than the ultrasonic waves transmitted from the two outer ultrasonic transducers to the central part. The ultrasonic waves transmitted from the acoustic transducer and returned from the object are received by the ultrasonic transducers of the ultrasonic transducer group, and the distance to the object is determined by measuring the round trip time of the ultrasonic waves. An ultrasonic detection method characterized by outputting a detection signal of an object when the object is within a predetermined distance. 11. It has an ultrasonic transducer group divided into at least three parts, one on both outer sides and a central part, and transmits ultrasonic waves from the ultrasonic transducers of the ultrasonic transducer group, and receives the ultrasonic waves returned from the object. The ultrasonic transducer in the center receives the ultrasonic wave with a higher sensitivity than the ultrasonic transducers on the both outer sides, and the distance to the object is determined by measuring the round trip time of the ultrasonic wave, and when the distance is within a predetermined distance, An ultrasonic detection method characterized by outputting a detection signal of the object.