JP2990941B2 - Ultrasonic sensor system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor system in which a plurality of ultrasonic sensors are juxtaposed.

[0002]

2. Description of the Related Art An example of a sensor system in which a plurality of ultrasonic sensors are juxtaposed is a cardboard box sorting system. FIG. 8 is a configuration perspective view showing a conventional example of a system for detecting and selecting the height of a cardboard box using a plurality of ultrasonic sensors. When sorting and sorting the cardboard placed and moving on the belt conveyor by its height, the ultrasonic sensor 1 as shown in FIG. 9 is moved in the traveling direction on the belt conveyor by 1a, 1b, 1c in FIG. Place them side by side as shown. Such an ultrasonic sensor 1 includes an ultrasonic transducer 2, a transmission circuit 3, a reception circuit 4, a ROM, an R
A one-chip microcomputer having an AM or the like and driven by a stabilized power supply 5 (hereinafter, this microcomputer is abbreviated as a microcomputer) 6, a measurement clock 7, a digital-analog conversion circuit 8, an output circuit 9, etc.
The electric vibration transmitted from the transmission circuit 3 is converted into ultrasonic waves by the vibrator 2 by the operation described above, and the ultrasonic wave is emitted toward an object to be detected (corrugated cardboard in this case), and a reflected wave reflected by the object is reflected by the vibrator 2. And converts it into electric vibration, sends it to the microcomputer 6 via the receiving circuit 4, and emits ultrasonic waves here.
The time until the reflected wave returns to the vibrator 2 is counted by the measurement clock circuit 7, and the distance is determined from this time. When the distance matches a preset distance, the digital-analog converter 8 converts the distance into an analog value, and outputs the analog value from the output circuit 9. For example, the highest cardboard is detected by the sensor 1a as having the shortest distance, and the next highest cardboard is detected by the sensor 1b as having a medium distance. Further, the lowest cardboard is detected by the sensor 1c as having the longest distance, and the detected cardboard is processed by the respective mechanisms based on the outputs of the sensors 1a, 1b, 1c and collected at, for example, each accumulation place.

[0003]

In the case where a plurality of ultrasonic sensors are used, when ultrasonic transducers are juxtaposed and juxtaposed, ultrasonic waves emitted from these transducers impinge on a corrugated cardboard and are reflected. Interference may occur before returning to the vibrator, and there has been a problem that reliable detection cannot be performed.

[0004] To solve this problem, Japanese Utility Model Application Laid-Open No. 2-8
No. 1487 has been proposed. FIG. 10 is a perspective view of the configuration, and FIG. 11 is a time chart of the control operation. The description of this content is omitted, but the point is that FIG.
A signal generator for sequentially outputting a signal, as shown in 14;
11 the output signal signal (after the "H""L" 1
8a, 18b, and 18c) are provided with external control signal generators each having an interface circuit applied to the microcomputer 6 of the ultrasonic sensor 1 (1a, 1b, 1c). (1a, 1b,
1c ...) as shown in FIG. 11 , the control signal 18 (18a, 18b,
18c), transmission and reception operations are performed alternately one by one to prevent interference between them. Although this system is sufficient in function, there is a problem that the cost of the external control signal generator is high, especially when the number of ultrasonic sensors is large, the cost of the signal generation unit becomes high.

It is an object of the present invention to provide an ultrasonic sensor system in which a plurality of ultrasonic sensors are juxtaposed to eliminate interference generated between these ultrasonic sensors at low cost.

[0006]

In order to achieve the above-mentioned object, the present invention relates to a sensor system in which a plurality of ultrasonic sensors are juxtaposed. an interface circuit for switching the transmission and reception operations of the ultrasonic sensor to the "inoperative" provided by it of these interface circuit
Each of the ultrasonic sensors other than the ultrasonic sensor to which it belongs
The detection signals are supplied as operation control signals via OR circuits. For example, each of the ultrasonic sensors outputs a detection signal of “H” at the time of detection, and each of the ultrasonic sensors controls the transmission / reception operation of the ultrasonic sensor by an operation control signal of “H” input from the outside. An interface circuit that switches to the "inactive" state is provided, and each of these interface circuits is
Of ultrasonic sensors other than the ultrasonic sensor to which
An “H” detection signal is input to each anode, and an “H” operation control signal is output from each cathode connected to the common through an OR circuit composed of a plurality of diodes.
Each of them is input as an operation control signal of “H”. Alternatively, each of the ultrasonic sensors outputs a detection signal of “L” at the time of detection, and the transmission / reception operation of this ultrasonic sensor is set to “non-operation” by an operation control signal of “L” input from the outside to each of these ultrasonic sensors. ”Is provided, and each of these interface circuits has its own ultrasonic sensor.
The detection signal of “L” of the ultrasonic sensor other than the above is input to each cathode, and “L” is output from each anode connected to the common.
The operation control signal is output as an “L” operation control signal via an OR circuit composed of a plurality of diodes to which the operation control signal is output. Further, the OR circuit is provided in each of the ultrasonic sensors provided with an interface through which the OR circuit outputs an operation control signal.

[0007]

In the ultrasonic sensor system of the present invention, when one of the plurality of ultrasonic sensors "operates", the detection signal is transmitted to the interface of the other ultrasonic sensor via the OR circuit. Each of the circuits is input as an operation control signal, and the transmission / reception operation of these other ultrasonic sensors is switched to “non-operation”, and the operation of the previous ultrasonic sensor is completed, and then the next ultrasonic sensor operates. Therefore, interference between the plurality of ultrasonic sensors arranged side by side is prevented.

[0008]

FIG. 1 is a circuit diagram including a partial model showing an embodiment of an ultrasonic sensor system according to the present invention. A plurality of ultrasonic sensors 1A which output an "H" detection signal upon detection.
(1Aa, 1Ab, 1Ac...) Are arranged side by side, and the detected object 12 sequentially passes through them.

These ultrasonic sensors 1A (1Aa, 1A)
b, 1Ac...) respectively, the operation control signals DA (DAa, DAb, DAc,.
..), the interface circuit 19A (19A) for switching the transmission / reception operation of the ultrasonic sensor to "non-operation".
a, 19Ab, 19Ac...) are provided, and these interface circuits 19A (19Aa, 19Ab, 19Ac) are provided.
Ac) are detection signals of “H” of ultrasonic sensors other than the ultrasonic sensor provided with the interface circuit (for example, 1Ab, 1Ac... For the ultrasonic sensor 1Aa). OR circuit 30A (30Aa, 30A
b, 30Ac...), the operation control signal D of “H”
A (DAa, DAb, DAc...). These OR circuits 30A (30Aa, 30A
b, 30Ac...) are composed of a plurality of diodes each of which receives the "H" detection signal to each anode and outputs the "H" operation control signal from each cathode connected to the common. .

FIG. 3 is a timing chart of the control operation. At time t ₀ , the detected object 12 has the ultrasonic sensors 1A (1Aa, 1Ab, 1Ac...) As shown in FIG.
·) Detection area 31A (31Aa, 31Ab, 31Ac)
…)) And these ultrasonic sensors 1A (1Aa, 1Aa,
1Ab, 1Ac...) Detection signal SA (SAa, SAa)
b, SAc · · ·) is "L", at time t _a detected body 12 of the ultrasonic sensor 1Aa detection area 31A
When the ultrasonic sensor 1Aa enters the position a (shown as 12a in FIG. 1), the detection signal SAa of "H" is output from the ultrasonic sensor 1Aa {FIG. This detection signal is used as an operation control signal DAb, DAc,.
b, 1Ac... each interface 19Ab, 19
Ac ... and these other ultrasonic sensors 1Ab,
1Ac... Is switched to non-operation {FIG. 3 (5),
(6)｝. At time t _b , when the detection target 12 advances to the position 12b in FIG. 1 and moves away from the detection area 31Aa of the ultrasonic sensor 1Aa and enters the detection area 31Ab of the ultrasonic sensor 1Ab, the detection signal of the ultrasonic sensor 1Aa becomes “L”. , And after a predetermined operation time, the detection signal SAb of “H” is output from the ultrasonic sensor 1Ab {FIGS. 3 (1) and (2)}. The detection signals are the operation control signals DAa, DAc,.
.. As well as other ultrasonic sensors 1Ac,... 1Aa
Is switched to non-operation {FIG. 3 (4), (6)}. As described above, when one of the plurality of ultrasonic sensors “operates”, the transmission / reception operation of the other ultrasonic sensor is switched to “non-operation”, and the ultrasonic sensor that has operated earlier Since the next ultrasonic sensor starts operating after the operation is completed, interference between the plurality of ultrasonic sensors arranged side by side is prevented.

FIG. 2 is a circuit diagram including a partial model showing a different embodiment of the ultrasonic sensor according to the present invention, and shows a plurality of ultrasonic sensors 1B which output an "L" detection signal upon detection.
(1Ba, 1Bb, 1Bc...) Are arranged side by side, and the detected object 12 sequentially passes through them.
These ultrasonic sensors 1B (1Ba, 1Bb, 1Bc...)
..) Respectively, an interface circuit 19B (19Ba, 19Bb) for switching the transmission / reception operation of the ultrasonic sensor to “inactive” by an “L” operation control signal DB (DBa, DBb, DBc...) Input from the outside. , 1
9Bc ...) are provided, and these interfaces 1
9B (19Ba, 19Bb, 19Bc ··· ) it
In addition, an ultrasonic sensor other than the ultrasonic sensor to which it belongs (for example, 1Bb, 1Bc for the ultrasonic sensor 1Ba)
..) Are OR circuits 30B, respectively.
(30Ba, 30Bb, 30Bc...) Through the operation control signal DB (DBa, DBb, DBc.
・ ・) These OR circuits 30
B (30Ba, 30Bb, 30Bc,...) Are output from a plurality of diodes each of which receives the “L” detection signal to each cathode and outputs an “L” operation control signal from each anode connected to the common. Has become.

In this ultrasonic sensor system, the signal polarity of each signal of the ultrasonic sensor system shown in FIG. 1 is inverted from "H" to "L", and the control operation time chart is omitted, but is shown in FIG. This is the same except that the polarity of the signal is inverted in the control time chart of FIG. FIG. 4 shows an example of the interface circuit 19A shown in FIG. 1. The collector is connected to a power supply 27 via a resistor 26, the emitter is connected to a ground terminal, and the base is connected to a signal input terminal JA via a resistor 21 and a Zener diode 22. A transistor 25 connected in each case and a diode 2 connected in parallel between the emitter and the base of the transistor 25.
3 and a resistor 24 and a transistor 25
Is connected to the input port of the microcomputer 6 of the ultrasonic sensor 1A. When an “H” signal is input to the signal input terminal JA, the transistor 25 is turned on, and the microcomputer 6
The input / output port is grounded so that the transmission / reception operation of the ultrasonic sensor 1A is "inactive". FIG. 5 shows an example of the circuit of the interface circuit 19B in FIG. And a signal input terminal JB, a diode 28 having an anode connected to the ground terminal, and a cathode of the diode 28 connected to an input port of the microcomputer 6 of the ultrasonic sensor 1B. When a signal of "L" is input to the signal input terminal JB, the diode 28 conducts, and the input port of the microcomputer 6 is grounded, so that the transmission / reception operation of the ultrasonic sensor 1B becomes "inoperative".

FIG. 6 shows each OR circuit 30A (3
0Aa, 30Ab, 30Ac...) Are respectively output to the interface circuits 19A (19Aa, 19Aa, 19Aa, 19A.
Ab, 19Ac ...) provided with the ultrasonic sensor 1A
(1Aa, 1Ab, 1Ac ...) shows the connection diagram when provided.

FIG. 7 shows each OR circuit 30B (3
0Ba, 30Bb, 30Bc,...) Are respectively output to the interface circuits 19B (19Ba, 19B, 19B, 19B, 19B, 19B, 19B) to which the operation control signals DB (DBa, DBb, DBc,.
Bb, 19Bc...) Are provided.
(1Ba, 1Bb, 1Bc ...) shows a connection diagram when provided. In FIG. 7, the interface circuits 19B (19Ba, 19Bb, 19Bc,.
.) Diode 29 is connected to OR circuit 30B (30Ba, 3
0Bb, 30Bc), and can be omitted.

By providing an OR circuit for each ultrasonic sensor as shown in FIG. 6 or FIG.
As a separate OR circuit as shown in (1) is eliminated, the configuration of the sensor system becomes easier.

[0016]

According to the ultrasonic sensor system of the present invention, when one of a plurality of ultrasonic sensors "operates", the detection signal is sent to another ultrasonic sensor via an OR circuit. Each of the interface circuits is input as an operation control signal, and the transmission / reception operation of these other ultrasonic sensors is switched to “non-operation”, and after the operation of the previously operated ultrasonic sensor is completed, the next ultrasonic sensor is operated. Interference between the plurality of ultrasonic sensors operatively arranged side by side is prevented. Since the OR circuit is simply composed of a plurality of diodes, the cost is extremely low.

[Brief description of the drawings]

FIG. 1 is a circuit diagram including a partial model showing an embodiment of an ultrasonic sensor system according to the present invention.

FIG. 2 is a circuit diagram including a partial model showing a different embodiment of the ultrasonic sensor system of the present invention.

FIG. 3 is a control operation time chart of the ultrasonic sensor system of the present invention shown in FIG.

FIG. 4 is a circuit diagram of the interface circuit of FIG. 1;

FIG. 5 is a circuit diagram of the interface circuit of FIG. 2;

FIG. 6 is a connection diagram when the OR circuit of FIG. 1 is provided in an ultrasonic sensor provided with an interface circuit to which an operation control signal is output;

FIG. 7 is a connection diagram in which the OR circuit of FIG. 2 is provided in an ultrasonic sensor provided with an interface circuit to which an operation control signal is output.

FIG. 8 is a configuration perspective view showing an example of a conventional ultrasonic sensor system.

FIG. 9 is a block diagram of the ultrasonic sensor in FIG. 8;

FIG. 10 is a configuration perspective view showing a different example of the conventional ultrasonic sensor system.

11 is a control operation time chart of the ultrasonic sensor system shown in FIG.

[Explanation of symbols]

 1A Ultrasonic sensor 1B Ultrasonic sensor 19A Interface circuit 19B Interface circuit 30A OR circuit 30B OR circuit SA detection signal SB detection signal DA operation control signal DB operation control signal

Claims (4)

(57) [Claims] In a sensor system in which a plurality of ultrasonic sensors are juxtaposed, an interface for switching the transmission / reception operation of the ultrasonic sensors to "non-operation" by an operation control signal input from the outside to each of the ultrasonic sensors. providing a circuit, it's these interface circuit
In addition, an ultrasonic sensor system characterized in that detection signals of ultrasonic sensors other than the ultrasonic sensor to which the self belongs belong to an OR circuit and are input as operation control signals. 2. In a sensor system in which a plurality of ultrasonic sensors are juxtaposed, each of the ultrasonic sensors outputs a detection signal of "H" upon detection, and each of these ultrasonic sensors receives an externally input "H" signal. the operation control signal of H "the transmission and reception operation of the ultrasonic sensor is provided an interface circuit for switching to the" dead ", to each of these interface circuit, an ultrasonic sensor for self belongs
The detection signal of "H" of the ultrasonic sensor other than the sensor is inputted to each anode, and the operation control signal of "H" is outputted from each cathode connected to the common through an OR circuit composed of a plurality of diodes. , "H" operation control signals. 3. In a sensor system in which a plurality of ultrasonic sensors are juxtaposed, each of said ultrasonic sensors outputs a detection signal of "L" upon detection, and each of these ultrasonic sensors receives an externally input "L" signal. the operation control signal of L "transmission and reception operation of the ultrasonic sensor is provided an interface circuit for switching to the" dead ", to each of these interface circuit, an ultrasonic sensor for self belongs
The "L" detection signal of the ultrasonic sensor other than the ultrasonic sensor is inputted to each cathode, and the "L" operation control signal is outputted from each anode connected to the common through an OR circuit composed of a plurality of diodes. , "L" operation control signals. 4. The ultrasonic sensor system according to claim 1, wherein the OR circuit comprises an OR circuit of the ultrasonic sensor .
An ultrasonic sensor system provided for each of them.