JPS63308589A - Ultrasonic object discriminating instrument - Google Patents

Abstract

PURPOSE:To prevent an incorrect operation due to an unnecessary reflection and improve an object detecting accuracy by discriminating a received signal from a prescribed distance by a gate circuit and integrating a reception levels from a reflecting object for a plurality of times. CONSTITUTION:A pulse-like ultrasonic wave emitted from a ultrasonic transmitter 13 is reflected from a reflecting objects 14 and 14' and received by ultrasonic receivers 15 and 15', respectively, arranged in parallel with respect to the transmitter 13. Received signals are inputted to gate circuits 17 and 17' via reception amplifier circuits 16 and 16', respectively. The circuits 17 and 17' generate pulse signals with a constant width at a delay time matched with a distance to the reflecting object 14 in synchronism with a reference pulse from a reference signal generating circuit 11 and allow a received output to be passed only for prescribed pulse widths. Accordingly, since the reflected wave from a reflection distance set in advance can be discriminated, an incorrect judgment to an unnecessary reflection is reduced. Then, after the outputs of the circuits 17 and 17' are counted for a plurality of times in integrating circuits 18 and 18', respectively, output levels are compared with each other in a control circuit 19. Thus, since a level judgment is effected based on the reception levels obtained for a plurality of times, a detecting accuracy can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ultrasonic object discrimination device that uses ultrasonic waves, and is particularly used in the industrial field as a sensor unit that detects the presence or absence of an object without contact. It is something that will be done.

2. Description of the Related Art Conventionally, this type of ultrasonic object discrimination device has had a configuration as shown in FIG. In FIG. 3, the transmitting section is composed of a pulse signal generation circuit 1, an ultrasonic oscillation circuit 2, and an ultrasonic transmitter 3. The receiving section includes an ultrasonic receiver 4 that receives the ultrasonic waves emitted from the transmitting section and reflected by the reflecting object 8, an amplifier circuit 5, and a receiver that determines whether the receiving output is at a receiving level equal to or higher than a reference value. It is comprised of a discrimination circuit 6 for discriminating the presence of a reflective object, and a control circuit 7 for discriminating the presence or absence of a reflective object and outputting it digitally.

Problems to be Solved by the Invention In such a conventional configuration, when there are multiple types of objects to be detected at the same position, there is a problem in that it is not possible to determine which object to be detected. be. Furthermore, if there is a reflective object in the vicinity, there is a problem of false detection.

The present invention is intended to solve these problems, and aims to provide a discrimination device that can discriminate two or more types of detected objects, minimizes malfunctions caused by nearby objects, and improves detection accuracy. be.

Means for Solving the Problem In order to solve this problem, the present invention connects an ultrasonic oscillation circuit to a reference signal generation circuit that oscillates a reference pulse, and an ultrasonic transmitter connected to the output end of this oscillation circuit. A transmitting unit that emits pulsed ultrasonic waves into the air from the device, and two or more ultrasonic receivers that receive all of the reflected ultrasonic waves from the reflecting object are provided, and the received signals received by each of the receivers are amplified respectively. two or more reception amplifier circuits that are synchronized with the reference signal and output the reception output of each of the reception amplifier circuits at the time of the ultrasonic wave that corresponds to the distance to the reflecting object. A gate circuit, two or more integrating circuits that are connected to the output terminals of each of the gate circuits and determine the reception level after receiving each received output multiple times in succession, and the output terminals of each of the above-mentioned integrating circuits are connected. The receiving section comprises a control circuit that compares and determines the reflection intensities of the respective receivers and outputs a digital signal.

Effect: With this configuration, a new function for detecting the movement of an object is added by using multiple receivers and determining the received ultrasonic strength of each. This prevents malfunctions caused by unnecessary ultrasonic waves caused by surrounding obstacles. Unfortunately, since the reflection intensity of a reflecting object is determined by integrating the reception levels multiple times, detection accuracy is increased.

Embodiment FIG. 1 is a block diagram of an ultrasonic object discrimination device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of signals of each part. In FIG. 1, reference numeral 11 denotes a reference signal generation circuit that generates the reference pulse 11a shown in FIG.

6h/Set the pulse period 20~100m5ec, reflect the object 1
Values are set corresponding to distances up to 4. Reference numeral 12 denotes an ultrasonic oscillation circuit which outputs an ultrasonic wave 12b shown in FIG. 25-200 KHz is used.

Reference numeral 13 denotes an ultrasonic transmitter consisting of an ultrasonic transducer made of a piezoelectric vibrator and a horn section for controlling directivity, and is connected to the output end of the ultrasonic oscillation circuit 12. The pulsed ultrasonic waves emitted into the air from this ultrasonic transmitter 13 are reflected from the reflecting object 14, 14', and are received by a first ultrasonic receiver located in parallel with the transmitter 13 at a certain distance. 15 and the second receiver 1d. At this time, if the ultrasonic transmitter and receiver are converters that can be used for both transmission and reception, for example, the first ultrasonic receiver 15 and the ultrasonic transmitter 13 are used as one for both transmission and reception, and the circuit is The received waves may be extracted after processing. In this case, the receivers 16 and 16' have the advantage of being miniaturized.
16', each of which amplifies the received signals received at
6 & and 1σa are output respectively. 17 and 17' are synchronized with the reference pulse, and pulse signals 17a and 17 of a constant width are generated at a delay time corresponding to the determination distance as shown in FIG. 2d.
'a, respectively, and pass the received output only during a certain pulse width. This gate circuit 17
, 17' are shown in FIG. 2e. 18
, 18' is an integrating circuit connected to the output ends of the gate circuits 17, 17', which counts the pulse outputs of the gate circuits 17, 17' a plurality of times, and after a predetermined number of times, the potential as shown in FIG. 2f is reached. It is intended to alleviate level fluctuations caused by disturbances in the ultrasonic waves in the air and movement of the reflecting object 14° 14'. 19 is the integration circuit 18, 1
This is a control circuit that compares and determines the output level of 8' and outputs a digital signal (control signal).

Here, it goes without saying that three or more ultrasonic receivers, reception amplifier circuits, gate circuits, and integration circuits constituting the reception section may be provided.

7. Effects of the Invention As described above, according to the present invention, the movement of the reflecting object can be determined by determining the amount of reflection by using a plurality of receivers and having a configuration in which the reflecting object can have a plurality of reflection positions. There is an effect that can be done. By setting the reflection distance in advance and providing a gate circuit that can discriminate the reflected waves at that distance, there are fewer false judgments due to unnecessary reflections, etc., and an integrating circuit is used to calculate the level based on the received level multiple times. The method of determining this has the effect of increasing detection accuracy.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of an ultrasonic object discrimination device according to an embodiment of the present invention, Fig. 2 shows a diagram explaining signals of each part in the device of the present invention, and Fig. 3 shows a conventional ultrasonic object detection device. FIG. 2 is a block diagram showing the device. 11...Reference signal generation circuit, 12...
Ultrasonic oscillation circuit, 13... Ultrasonic transmitter, 14
, 14'... Reflecting object, 16... Ultrasonic receiver, 16, 16'... First. Second ultrasonic receiver, 16, 16'... Reception amplifier circuit, 17.1 γ'... Gate circuit, 18° 18
'...Integrator circuit, 19...Control circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

Claims (1)

[Claims] an ultrasonic oscillation circuit is connected to a reference signal generation circuit that oscillates reference pulses, and a transmitter that transmits pulsed ultrasonic waves into the air from an ultrasonic transmitter connected to the output end of the oscillation circuit;
2 ultrasonic receivers that receive reflected ultrasonic waves from reflective objects.
two or more reception amplification circuits for respectively amplifying the received signals received by the respective receivers, and two or more reception amplification circuits for respectively amplifying the reception signals received by the respective receivers, and synchronized with the reference signal generation circuit, and at a time interval of the ultrasonic waves corresponding to the distance to the reflecting object. two or more gate circuits that respectively output the received outputs of each of the above-mentioned receiving amplifier circuits, and are connected to the output terminals of each of the gate circuits, and after successively receiving each received output multiple times, determine the reception level. an ultrasonic receiver comprising two or more integrating circuits, and a control circuit that connects the output ends of each of the integrating circuits, compares and discriminates the reflection intensity of each of the receivers, and outputs a digital signal. Object discrimination device.