JPH0352032B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an ultrasonic detector that detects an object based on the time delay of the reflected waves of an intermittently emitted ultrasonic pulse from the object. be.

[Background Art] Conventionally, this type of ultrasonic detector intermittently emits ultrasonic pulses into space from a transmitting means, and receives reflected waves from an object to be detected such as an object or a human body by a receiving means. It was designed to detect whether an object to be detected exists within a predetermined detection range by receiving the waves.
By the way, in such conventional examples, the detection range in which the object to be detected can be detected is limited by the directivity of the ultrasonic pulse transmitter and the reflected wave receiver or the distance setting of the distance gate. When detecting an object using multiple ultrasonic detectors, there are problems in that a large blind spot occurs and a detection range of arbitrary shape cannot be set. In other _{words ,} with _the ultrasonic detector ₁ −D ₁ ), the detection range DE ₁ is the ultrasonic detector
It is determined by the directivity of the transducer of X′, and it is difficult to match this directivity with the detection range DE ₀ , so
There was a problem in that large blind spots (shaded areas Y ₁ and Y ₂ ) were created on both sides of X′ where the object to be detected could not be detected. Therefore, in order to eliminate the influence of directivity and reduce the blind spot mentioned above, ultrasonic waves are designed to detect the time delay of the reflected wave relative to the ultrasonic pulse and set the detection range, that is, the detection distance, for detecting the detected object. Detector X″ was hot. However,
When you want to obtain the detection range DE ₀ ′ (A _{2 −B 2} −C ₂ −D ₂ ) as shown in Fig. 6 with this ultrasonic detector A ₂ D ₂ or
B ₂ C ₂ ), the detection range DE ₂ becomes significantly smaller than the desired detection range DE ₀ ′, and new blind spots (shaded areas Y ₃ ) occur in both lateral directions.
On the other hand, if the detection distance is increased and set to l ₂ (diagonal length X″C ₂ or X″D ₂ ) in order to prevent such a blind spot from occurring, the detection range DE ₂ ′ in the front direction There was a problem in that the detection distance became too large and an unnecessary detection range (shaded area Y ₄ ) was generated, making it impossible to obtain a detection range DE ₀ ' with an arbitrary shape.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to reduce blind spots in which objects to be detected cannot be detected, and to enable detection ranges of arbitrary shapes to be reduced. The object of the present invention is to provide an ultrasonic detector that can be configured.

[Disclosure of the Invention] (Embodiment) Fig. 1 shows an embodiment of the present invention, in which ultrasonic pulses are intermittently emitted toward space from a wave transmitting means 1, and an ultrasonic pulse is emitted toward an object by a wave receiving means 2. The detection range setting means 3 receives a reflected wave from an object M to be detected such as a person or a human body, and sets a detection range based on the time delay of the received reflected wave with respect to the ultrasonic pulse. In an ultrasonic detector configured to detect A detection range setting means 3 is formed by distance gates 3a to 3d for setting a detection distance.

Here, the wave transmitting means 1 includes a periodic oscillation circuit 10 that generates a synchronous pulse for setting the emission timing of the ultrasonic pulse, a wave transmitting gate circuit 11 that sets the pulse width of the ultrasonic pulse, and a wave transmitting gate circuit 11. The drive circuit 12 drives the wave transmitting transducer 13 which is controlled by the output of the wave transmitting transducer 13 and generates a drive signal of a predetermined carrier frequency. It is designed to fire over a wide area (wide angle) towards the space that is the detection range. The wave receiving means 2 includes wave receiving transducers 15a and 15b arranged in parallel with a predetermined distance apart.
, amplification circuits 16a, 16b that amplify the outputs of the receiving transducers 15a, 15b, and detection circuits 17a, 1.
7b and waveform shaping circuits 18a, 18b, the reflected waves of the ultrasonic pulses from the detected object M are received by the respective receiving transducers 15a, 15b, and the waves are received from the waveform shaping circuits 18a, 18b, respectively. It is designed to output signals (received signals of reflected waves with different propagation paths). The division determination means 4 includes an azimuth gate setting circuit 20 that sets the azimuth angles θ ₁ to _{θ 4} ;
It is formed by a differentiating circuit 21 and AND circuits 22a to 22d, and divides the azimuth angle range of the reflected wave to be detected into a plurality of parts (eight parts in the embodiment) and calculates the received signal.
It is designed to determine which divided azimuth angle range V ₁ and V ₂ correspond to. Detection range setting means 3
The distance gate setting means 23 and the AND circuit 24
a to 24d, and it is configured to detect whether the reflected wave is from within the detection distance _l1 to _l4 based on the time delay from the emission timing of the ultrasonic pulse to the reception timing of the reflected wave. The detection signal generation circuit 5 is configured to output an object detection signal when an output is obtained from any of the AND circuits 24a to 24d of the detection range setting means 3, and this object detection signal is sent via the output circuit 6. It is designed to be outputted to control alarm means, etc. Note that the division determining means 4 of the embodiment includes wave receiving transducers 15a, 1
Although the azimuth angles θ ₁ to _{θ 4} are set based on the time difference between the received signals V ₁ and V ₂ received at 5b, the phase difference between the received signals V ₁ and V ₂ is detected. Needless to say, it is equivalent to setting the azimuth angles θ ₁ to _{θ 4} as follows.

The operation of the embodiment will be described below. now,
In the ultrasonic detector X of the embodiment, as _shown in _FIG . The azimuth angle range of the wave is divided, and four divided azimuth angle ranges H ₁ to _{H 4} are set on the left and right sides respectively.
It is determined from which azimuth angle range H ₁ to _{H 4} the reflected waves are reflected by V ₁ and V ₁ . This AND circuit 22a-2
The 2d output is for each distance gate 3 of the detection range setting means 3.
a to 3d, each divided azimuth angle range H ₁ to _{H 4}
Each time, AND circuits 24a to 24d determine whether the distance is within the respective set detection distances _l1 to _l4 . Any AND circuit 2
When outputs 4a to 24d are obtained, that is, when it is determined that the reflected waves from any of the divided azimuth angle ranges H ₁ to _{H 4} are reflected waves from within the detection distances l ₁ to _{l 4} , respectively, An object detection signal is output from the detection signal generation circuit 5, and an alarm means is driven via the output circuit 6. In this way, the detection distance _l1 to _l4 corresponds to each divided azimuth range _H1 to _H4 .
By appropriately setting DE ₀ ″ (A ₃ − B ₃ − C ₃ − D ₃ ) to obtain the desired detection range, the blind spot (shaded area Y ₅ ) and unnecessary detection range (shaded area
Y ₆ ) can _be significantly reduced compared to _the conventional example, and with one ultrasonic detector ing.

Embodiment 2 FIG. 3 shows another embodiment, in which a large number of azimuth angles θ ₁ to θn are set to divide the azimuth angle range to be detected, and the division determination means 4 divides the azimuth angle range H ₁ to
Make Hn finer, each division azimuth range H ₁ ~ Hn
The detection distances l ₁ to ln are set respectively correspondingly, and by increasing the number of divisions n of the azimuth angle range, any detection range can be set.
A detection range closer to DE ₀ ″ can be achieved,
Blind spots and unnecessary detection ranges can now be almost eliminated.

Embodiment 3 FIG. 4 shows still another embodiment, in which the azimuth angle is set three-dimensionally, the azimuth angle range in which the reflected waves to be detected are received is divided three-dimensionally, and each division is Detection distances are set for each azimuth angle range, reducing blind spots and unnecessary detection ranges.
Furthermore, a detection range close to the arbitrary three-dimensional detection range DE ₀₃ can be easily obtained.

[Effects of the Invention] As described above, the present invention emits ultrasonic pulses intermittently toward space from the wave transmitting means, and
A detection device setting means is used that receives a reflected wave from an object to be detected such as an object or a human body using a wave receiving means, and sets a detection range based on a time delay of the received reflected wave with respect to an ultrasonic pulse. In an ultrasonic detector configured to detect an object to be detected, ultrasonic pulses are emitted from a wave transmitting means over a wide range of space, and a pair of receiving transducers arranged in parallel at a predetermined distance output. A division determination means is provided for determining the azimuth of the reflected wave to be detected based on the time difference or phase difference between the two, dividing the azimuth angle range into a plurality of parts, and discriminating the received signal. Since the detection range setting means is formed by the distance gate that sets the distance, by appropriately setting the detection distance corresponding to each divided azimuth angle range so as to obtain the desired detection range, blind spots and unnecessary The detection range can be significantly reduced compared to the conventional example, and there is an effect that a detection range that is almost the same as a detection range of an arbitrary shape can be easily set. In addition, the reflected waves of the ultrasonic pulses emitted from the wave transmitting means over a wide range of space from the object to be detected are received by a pair of wave receiving transducers arranged in parallel with a predetermined distance apart. A division discrimination means is provided which determines the azimuth of the reflected wave to be detected based on the output of the wave receiving transducer, divides the azimuth angle range into a plurality of parts, and discriminates the received signal. Since this is done statically, it has the effect of allowing accurate division settings for the azimuth angle range.Moreover, by transmitting one ultrasonic pulse and receiving the reflected wave, the entire azimuth angle range can be covered. Since the detection object can be detected, there is an effect that the detection time can be shortened.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of one embodiment of the present invention, Fig. 2 is an explanatory diagram of the same operation as above, Figs. 3 and 4 are explanatory diagrams of other embodiments, and Fig. 5 is an explanation of the operation of the conventional example. FIG. 6 is an explanatory diagram of the operation of another conventional example. 1 is a wave transmitting means, 2 is a wave receiving means, 3 is a detection range setting means, and 4 is a division determining means.

Claims (1)

[Claims] 1 The transmitting means intermittently emits ultrasonic pulses into space, and the receiving means receives reflected waves from objects to be detected such as objects and human bodies, and the ultrasonic pulses of the received reflected waves are In an ultrasonic detector configured to detect an object using a detection range setting means that sets a detection range based on a time delay with respect to a sound wave pulse, the ultrasonic pulse is directed from a wave transmitting means to a wide range of space. The azimuth angle of the reflected wave to be detected is determined based on the time difference or phase difference between the outputs of a pair of wave receiving transducers placed in parallel at a predetermined distance apart, and the azimuth range is divided into multiple waves for reception. What is claimed is: 1. An ultrasonic detector characterized in that a decomposition determination means for determining a wave signal is provided, and a detection range setting means is formed by a distance gate for setting a detection distance for each divided azimuth angle range.