JPS6270779A - Ultrasonic matter detector - Google Patents

Abstract

PURPOSE:To make it possible to reduce the possibility of erroneous operation, by shortening the transmitting interval of an ultrasonic pulse as compared with that at the time of non-detection when the reflected wave from a matter was detected and reducing the reception of interference from other ultrasonic matter detector at a usual time. CONSTITUTION:The transmitting signal of an ultrasonic wave is formed by a transmitting signal generating circuit 2 and the ultrasonic wave is emitted by an ultrasonic sensor 1 being a vibrator. At the same time, the detection gate corresponding to a predetermined detection distance range is opened in a detection circuit 4. When the reflected wave from matter is received by the sensor 1, this receiving signal is inputted to the circuit 4 through an amplifying/ detection circuit 3. Subsequently, the circuit 4 and a signal processing circuit 5 judges that the matter is present within a predetermined distance to display the same on a display device 7. When an usual receiving signal is not detected, setting is performed so as to hold a definite transmitting interval or more. Further, a transmitting interval determining circuit 6 is operated when the receiving signal was detected and the transmitting interval is shortened. By this method, the possibility of erroneous operation can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an ultrasonic object detector that detects objects using ultrasonic waves.

[Background technology]

Conventionally, in ultrasonic object detectors, the presence of an object has been confirmed by performing two or three consecutive detections of intermittent ultrasonic pulses to prevent false alarms.
In the case of this conventional example, the transmission interval of the ultrasonic pulses was not changed, so it took a long time to confirm, and if the object was moving at high speed or the detector itself was moving at high speed, the object could not be confirmed. There was a problem in that it caused

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic object detector that can reliably detect the presence of an object even when the object or the detector side moves at high speed, and that reduces false alarms by shortening the transmission pulse interval. That is.

[Disclosure of the invention]

FIG. 1 is a basic block diagram of an embodiment of the present invention.
The ultrasonic sensor (11), the transmission signal generation circuit (2) for inputting an ultrasonic signal to this ultrasonic sensor +1+, and the received signal when the ultrasonic sensor f1 receives a reflected wave. an amplification/detection circuit (3) that amplifies and detects a wave; a detection circuit (4) that detects an object within a detection area based on the signal from this amplification/detection circuit (3) and the transmitted signal; and a detection area. A signal processing circuit (6
), and is further provided with a transmission interval determining circuit (6) that switches (variably) controls the generation interval of the transmission signal by the transmission signal generation circuit (2) according to the detection output of the detection circuit (4). It is being

Next, the operation of the zero invention-embodiment will be explained with reference to the time chart shown in FIG. First, in the period t = to −to,
As shown in FIG. 4A, an ultrasonic transmission signal is generated by the transmission signal generation circuit (2), and the ultrasonic wave is emitted by the ultrasonic sensor fi+, which is a vibrator. At the same time, the detection circuit (4) opens a detection gate as shown in Fig. 2(b) corresponding to a predetermined detection distance range from t''tt to t2. Such a reflected wave is an ultrasonic sensor +1)
When the received signal is received by the amplification/detection circuit (3)
is input to the detection circuit (4) via the detection circuit (4) and the signal processing circuit (
5) and displays it on the display (7) K.The present invention has the advantage that the transmission interval of the ultrasonic pulses is varied depending on the presence or absence of the received signal as shown in Fig. 2. It has the following characteristics. In other words, when the detection circuit (4) detects a received signal as shown in (d) in the same figure, the transmission interval is shortened. If waves are constantly transmitted at pulse intervals, the ultrasonic detector is likely to be influenced by other ultrasonic detectors that are transmitting waves at the same intervals, and the probability of false alarms is correspondingly high. However, if the transmission interval is maintained at a certain level or more, the probability of false alarms will be reduced. Therefore, in the present invention, when a normal received signal is not detected, the transmitting interval is set to be maintained at a certain level or more, as shown in Figure (d).
When a received signal is detected, the transmission interval determination circuit (6
) to shorten the transmission interval as shown in (a) of the same figure.

Figure 3 is an explanation of the input state of the received signal from the first received signal input until the display (7) becomes operational. ) show examples of the first and second stones, respectively. Thus, with the conventional method shown in Figure (a), when performing two or three consecutive detections (three consecutive detections in the figure), which is a method for reliable confirmation of an object, the time shown in the diagram is In the case of the first embodiment shown in the figure (b), if what is required is two or three consecutive times, which is the same as in the conventional example, it can be confirmed in a much shorter time than in the conventional example; In this case, as in the second embodiment shown in FIG. 6(C), confirmation can be performed n times, and more reliable confirmation can be achieved.

If confirmation can be performed in a shorter time than before, it will be possible to reliably detect objects or detectors even if they move at high speed.

〔Effect of the invention〕

The present invention is configured as described above, and when a reflected wave from an object is detected, the transmission interval of ultrasonic pulses is made shorter than when it is not detected. There is less interference from the object detector, greatly reducing the possibility of malfunctions, and object detection can be confirmed at high speed when necessary. This has the effect of making it possible to reliably detect and confirm an object even when moving at high speed.

[Brief explanation of drawings]

Fig. 1 is a block diagram of one embodiment of the present invention, Fig. 2 is an explanatory diagram of the same interlacing, and Figs. 3 (a) to (C) are reception waves of the conventional example and the first and second embodiments, respectively. FIG. 3 is an explanatory diagram of signal detection. Agent Patent Attorney Ishi 1) Chief Voluntary author of 7 procedural amendments) 1. Incident display 1985 patent N! #211319 No. 2, name of the invention Ultrasonic object detector 3, relationship with the case of the person making the amendment Patent applicant address 1048 Kadoma, Kadoma City, Osaka Prefecture Name (58
3) Representative of Matsushita Electric Works Co., Ltd. Sadao Fujii 4 Agent postal code 530 Address 1-12-17-5 Umeda, Kita-ku, Osaka City Date of amendment order Vol. 6 Number of inventions increased by amendment None 7, correction, t
1) "Diagram for explaining intercropping" on page 6, line 11 of the specification of the present application is corrected to "Diagram for explaining operation."

Claims (3)

[Claims] (1) Ultrasonic waves that detect the presence of an object by transmitting ultrasonic pulses intermittently and continuously receiving reflected waves from the object in response to multiple transmitted ultrasonic pulses. When an object detector detects a reflected wave from an object,
An ultrasonic object detector comprising: a transmission interval switching means that shortens the transmission interval of ultrasonic pulses compared to when no detection is being performed. (2) If the transmission interval switching means continues to detect reflected waves from an object even after the transmission interval of ultrasonic pulses has been shortened, the transmission interval switching means will change the transmission interval based on the transmission interval after a preset period of time has elapsed. The ultrasonic object detector according to claim 1, wherein the ultrasonic object detector operates to return the object. (3) The ultrasonic object detector according to claim 1 or 2, wherein the transmission interval switching means changes the transmission interval in accordance with the approaching speed of the object.