JPS60256077A - Apparatus for detecting object by using ultrasonic wave - Google Patents

Abstract

PURPOSE:To discriminate the presence or absence of an object, by simple constitution using a means for sampling the output of a detection apparatus for detecting the reflected wave of an ultrasonic wave successively projected at every definite angle. CONSTITUTION:The projection of an ultrasonic wave and the detection of the reflected wave thereof are performed by fractionally changing an angle, for example, within a range of 90 deg. and the results thereof are stored in a microcomputer 2. The stored data are shown as black dots each being a point where a sampling value came to a high level and white dots each being a point where said sampling value came to a low level. When predetermined sampling data (that is, sampling data of a high level) almost equal in a definite angle range to an arbitrary ultrasonic wave projection angle are obtained, the microcomputer 2 discriminates that an object is present at the place corresponding to the place where said sampling data were obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an object detection device using ultrasonic waves, and particularly relates to an object detection device using ultrasonic waves that is improved in determining the presence or absence of a detected object. .

BACKGROUND OF THE INVENTION FIG. 1 is a block diagram of an example of a conventional object detection device using ultrasonic waves, and FIG. 2 is a timing chart of signals of each part to explain the operation of FIG. be. Referring to FIGS. 1 and 2, a conventional object detection device using ultrasonic waves will be described first.

The ultrasonic wave emitting device 1 continuously outputs ultrasonic waves of, for example, 40 KHz, and supplies them to one input terminal of the AND gate 3 . At the start of measurement, the micro-fitter 2 outputs a rectangular wave of 300 μs, for example, as shown in FIG. This signal is applied to the set terminal of the knob 9, and the flip 70 knob 9 is set at the rising timing.

The output of the AND gate 3 becomes the output shown in FIG. 2(b). This output is amplified by the amplifier circuit 4 and projected from the ultrasonic projection device 5 in a predetermined direction.

The ultrasonic detection device 6 is a device mainly for detecting reflected waves (ultrasonic waves) returning from the direction in which the ultrasonic projection device 5 projected. When a reflected wave is detected by this device 6,
This detection output is as shown in FIG. 2(C). The detected ultrasonic signal is amplified and detected by the amplification/detection circuit 7, resulting in a signal having the waveform shown in FIG. 2(d). Further, this signal is waveform-shaped by the shaping circuit 8 to become the signal shown in FIG. 2(e), and is applied to the reset terminal of the flip-flop 9.

As a result, the flip 70 knob 9, which was set at the timing of the rise of the signal <a> as described above, is reset at the timing of the rise of the signal <a> as shown in FIG. 2(e).

Therefore, the output of the flip-flop 9 is as shown in FIG. 2(f).
As shown in FIG. 2, the pulse signal becomes a high level at the rising edge of the output pulse from the microcomputer 2, and inverts to O- level at the rising edge of the output pulse from the shaping circuit 8.

Therefore, in the microcomputer 2, during the period when the output of the flip 70 knob 9 is at a high level, ! In other words, by timing the set time of the flip 70 knob 9, ultrasonic waves are projected from the ultrasonic projection @If5, reflected by an object, and detected by the ultrasonic detection device 16. By multiplying this time by the speed of the ultrasonic wave and dividing it by half, the distance from the projection device w5 (or the detection device 6) to the object can be determined.

However, a drawback of this conventional @ placement is that the 7 lip 70 tube 9 is often reset due to an erroneously detected signal. This is because not only normal reflected waves but also noise etc. are input to the ultrasonic detection device I6. These noises are generally very short signals, but when this signal is amplified, detected, shaped, and given to the flip-flop 9, the flip-flop 70 knob 9 is reset at the rising timing. This is because the output was often incorrect.

OBJECTS OF THE INVENTION Therefore, an object of the present invention is to provide an object detection device using ultrasonic waves that can accurately detect objects.

Structure of the Invention The present invention includes an ultrasonic detection device that includes a projection device that sequentially projects ultrasonic waves at each fixed angle, and a detection device that detects reflected waves of the projected ultrasonic waves for each projection angle. . In addition, means for sampling the output of the detection device at fixed time intervals based on the output time of the projection device, and means for storing the sampled data are approximately equal within a certain angle range for any ultrasonic projection angle. The configuration includes a determining means that determines that an object is present based on the sampling data when predetermined sampling data is obtained.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings in order to make the above-described structure and features of the present invention clearer.

FIG. 3 is a block diagram of the configuration of an embodiment of the present invention. 35th! ! 1, the same components as those of the conventional device shown in FIG. 1 are given the same numbers. A feature of the embodiment shown in FIG. 3 is that the output of the shaping circuit 8 is directly given to the microcomputer 2.

When the rectangular wave (FIG. 4(a)) for ultrasonic output is output, the microcomputer 2 samples the input from the shaping circuit 8 at regular intervals based on the rising timing of the rectangular wave. It works like this. Then, as shown in FIG. 4 (9) and (h), the sampling data is stored as digital data of "1" or "0" depending on whether the output of the shaping circuit 8 is high level or low level at each sampling time. do. In this case, the fourth
As shown in Figure (g), if not only normal reflected waves but also noise is mixed in at the time of sampling, the sampling data becomes high level based on the noise.

In the above manner, ultrasonic waves are projected at any angle,
When the reflected wave is detected, the projection angle is then shifted by a certain angle, and the reflected wave is detected in the same way. This process is repeated, and as shown in FIG.
is memorized. This stored data may be stored, for example, in the fifth
The data is as shown in the figure. In FIG. 5, black circles are points where the sampling value is high level, and white circles are points where the sampling value is low level.

In the microcomputer 2, when almost equal predetermined sampling data (i.e., high-level sampling data) is obtained within a certain angular range for any ultrasonic projection angle, it corresponds to the location where the sampling data was obtained. It is determined that an object exists at the location where the object is located. Simply put, in FIG. 5, it is determined that an object exists where the black circles are clustered.

According to this method of discrimination, even if noise happens to be mixed in during sampling and the sampling data reaches a high level, the data based on such noise will only be obtained sporadically; Since it is not uniformly obtained within the angular range, false detections due to noise can be reliably removed.

Furthermore, compared to the conventional device, this embodiment does not use a flip 70 tab and has a simpler configuration, and can be used, for example, in what is called a back sonar for automobiles.

Effects of the Invention As described above, according to the present invention, it is possible to obtain an object detection device using ultrasonic waves that has a simple configuration and can obtain accurate detection results.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional object detection device using ultrasonic waves. FIG. 2 is a signal timing diagram for explaining the operation of FIG. 1. FIG. 3 is a block diagram of an embodiment of the present invention. FIG. 4 is a signal timing diagram for explaining the operation of FIG. 3. FIG. 5 is an illustrative diagram showing an example of sampling data detected by the embodiment shown in FIG. In the figure, 1 is an ultrasonic generator, 22 is a microcomputer, 3 is an AND gate, 4 is an amplifier circuit, 5 is a projection device, 6 is a detection device, 7 is an amplification/detection circuit, and 8 is a shaping circuit. (and 2 others) Figure 1 Figure 2 Figure 3 Figure 4 (h) 5th...

Claims (1)

[Scope of Claims] An ultrasonic measurement device comprising a projection device that sequentially projects ultrasonic waves at fixed angles, and a reflected wave detection device that detects reflected waves of the projected ultrasonic waves for each projection angle. , means for sampling the output of the detection device at regular intervals with reference to the output time of the projection device; means for storing the sampled data; means for determining that an object is present based on the sampling data when approximately equal predetermined sampling data is obtained;
Object detection device using ultrasonic waves.