JPH0778840B2 - Ultrasonic proximity object detector - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic proximity object detection device for detecting an object existing in proximity, for example, a parked vehicle in an indoor parking lot in a building or the like.

2. Description of the Related Art The principle of a conventional method for detecting a parked vehicle in a parking lot using ultrasonic waves is shown in FIG. In the figure, 1a, 1b and 1c are ultrasonic sensors, and 2a and 2b are vehicles. Each ultrasonic sensor 1a, 1b, 1c,
As shown in FIG. 6, it is installed above the corresponding detection point, and after emitting the ultrasonic wave Ps toward the road surface below, whether the reflected wave is received by the emitting ultrasonic sensor within a certain gate time. Based on this, the vehicle reflected wave Po and the road surface reflected wave Pr are discriminated, and when the vehicle reflected wave Po is received, the presence of the vehicle 2a or 2b at the detection point is detected.

By the way, in the case of an indoor parking lot such as a building, the parking interval is narrow and the detection points are close to each other.
Normally, a, 1b and 1c are placed close to each other. Therefore, as shown in FIG. 5, for example, the ultrasonic wave radiated from the ultrasonic sensor 1a hits the spherical portion of the vehicle 2a and is received by the adjacent ultrasonic sensor 1b as a sneak wave P and is erroneously detected. However, in the related art, the erroneous detection due to the wraparound wave P is prevented by making the following improvements.

That is, the relation between the installation height H and the installation interval of each ultrasonic sensor, the height h of the detected object, etc. is set so that the propagation distance of the wraparound wave P is always longer than the propagation distance of the road surface reflected wave Pr. Even if the wraparound wave P is generated, the ultrasonic waves Ps emitted from the ultrasonic sensors 1a, 1b, 1c are synchronized so that the emission times of all the sensors are the same at the same time. As shown, the wraparound wave P is always received after the road surface reflected wave Pr, thereby preventing occurrence of erroneous detection due to the wraparound wave P from the adjacent ultrasonic sensors. .

Problems to be Solved by the Invention Conventionally, erroneous detection due to a wraparound wave from an adjacent ultrasonic sensor was prevented as described above, but in the case of such a method, the height h of the detected object is On the other hand, conditions such as that the mounting height H of the ultrasonic sensors can be made sufficiently large and that the installation intervals of the adjacent ultrasonic sensors can be made sufficiently wide are required.

However, in an indoor parking lot such as a building and other places where there is no room for installation space, there are restrictions on the mounting height and the installation interval, and it is difficult to apply the conventional detection method to any place. Therefore, it has been desired to develop an ultrasonic proximity object detection apparatus that can be applied to any place and detect the presence or absence of a proximity object without being restricted by the installation conditions as described above.

Means for Solving the Problems The present invention has been invented to solve the above-mentioned problems, and is a novel ultra-sized device that can be applied to any place without being restricted by installation conditions to detect a proximity object. A sound wave type proximity object detection device is provided.

That is, the device of the present invention is provided with ultrasonic sensors respectively corresponding to a plurality of detection points adjacent to each other in order to solve the above-mentioned problems, and reflected waves of ultrasonic waves emitted from each sensor toward the corresponding detection point are A detection device for a proximity object using ultrasonic waves for detecting that an object to be detected is present at the detection point when received by each radiated ultrasonic sensor within a fixed gate time, wherein each of the ultrasonic sensors The operating order is determined in advance, and the ultrasonic sensor of the next order emits ultrasonic waves toward the corresponding detection point by the ultrasonic sensor of the higher order according to the operating order, and then the ultrasonic sensor of the next order is placed with a predetermined delay time. From the ultrasonic sensor to the corresponding detection point, and then sequentially emits ultrasonic waves from the ultrasonic sensors in the subsequent order to the corresponding detection points at predetermined delay time intervals. It is those, which is configured as.

That is, the ultrasonic proximity object detection device is composed of a plurality of ultrasonic sensors provided corresponding to a plurality of adjacent detection points, and the ultrasonic sensors are connected in series. Each of the ultrasonic sensors is provided with a delay circuit, each ultrasonic sensor receives a pulse signal input from the outside and radiates an ultrasonic wave toward a corresponding detection point, and after radiating the ultrasonic wave through the delay circuit, Each ultrasonic sensor outputs a pulse signal after a predetermined delay time, and ultrasonic waves are sequentially emitted from each ultrasonic sensor at intervals of each delay time. Of the ultrasonic sensors, the ultrasonic sensors are connected in series, and each ultrasonic sensor is provided with a delay circuit. Receives a pulse signal input from the outside, emits ultrasonic waves toward the corresponding detection point after a predetermined delay time through the delay circuit, and at the same time outputs a pulse signal to the ultrasonic sensor of the rear order, The ultrasonic wave sensor is configured to sequentially emit ultrasonic waves at respective delay time intervals.

Operation When the device of the present invention is used, the ultrasonic wave emission time of each ultrasonic sensor provided corresponding to a plurality of detection points is sequentially shifted by a predetermined delay time according to a predetermined operation order. Therefore, if the delay time of each ultrasonic sensor is set to a predetermined value in advance according to the installation conditions, even if a wraparound wave is generated by an adjacent ultrasonic sensor, the wraparound wave will not be generated. The ultrasonic sensor does not receive the signal within the reception gate time. Therefore, even if a wraparound wave is generated, it does not interfere with the detection operation of another ultrasonic sensor, and it is possible to prevent erroneous detection from occurring.

Further, the ultrasonic sensor according to the present invention emits ultrasonic waves of each ultrasonic sensor by successively connecting the pulse signals output from the higher ultrasonic sensors to the pulse input terminals of the ultrasonic sensors of the next order. Each time can be automatically delayed by a predetermined time.

EXAMPLE FIG. 1 shows an example of an ultrasonic sensor used in the ultrasonic proximity object detection apparatus according to the present invention for use in carrying out the method of the present invention, 3 is an ultrasonic handset, and 4 is ultrasonic transmission. circuit,
Reference numeral 5 is an ultrasonic wave receiving circuit, and 6 is a pulse circuit. The circuits other than the pulse circuit 6 are conventionally known circuits.

The pulse circuit 6 outputs ultrasonic waves from the handset 3 at the internally set transmission repetition cycle To when the pulse switching switch 7 is set to the "parent" side, and when it is set to the "child" side. A counter 9 that operates so as to immediately output an ultrasonic wave upon receiving a pulse signal externally input to the pulse input terminal 8 and an ultrasonic wave output by the counter 9 and then a predetermined delay time T ₁ The delay circuit 11 outputs a synchronization signal to the synchronization output terminal 10 after a lapse of time. It goes without saying that the transmission repetition cycle To of the counter 9 and the delay time T ₁ of the delay circuit 11 can be set to arbitrary values.

FIG. 2 shows the structure of the ultrasonic type proximity object detecting device according to the present invention, which is constructed by using the ultrasonic sensor of FIG. 1 mentioned above. This example of FIG. 2 is the same as the case of FIG. It is an example when the invention device is applied.

As is apparent from FIG. 2, the device of the present invention is provided with ultrasonic sensors 1a, 1b, 1c of the ultrasonic proximity object detection device according to the present invention shown in FIG. 1 corresponding to respective detection points. , The pulse signal output from the pulse output terminal 10 of the ultrasonic sensor 1a of the highest order (parent) is connected to the pulse input terminal 8 of the ultrasonic sensor 1b of the next order, and the ultrasonic sensor of the second order is further connected.
The pulse signal output from the pulse output terminal 10 of 1b
The ultrasonic sensor 1c is connected to the pulse input terminal 8 of the order, and similarly, the pulse output terminals and the pulse input terminals of the ultrasonic sensors are connected one after another in a predetermined order. The ultrasonic sensor 1a, which is the highest level (parent), sets the pulse switching switch 7 in the pulse circuit 6 to the "parent" side, and is internally set by the counter 9 as shown in FIG. 3 (a). The ultrasonic sensors 1b and 1c of the lower order (child) have the pulse switching switches 7 in the pulse circuit 6 set to the "child" side and the upper side, respectively. When the pulse signal S (Figs. 3 (c) and (f)) is received from each of the ultrasonic sensors, the ultrasonic waves Ps are output (Figs. 3 (d) and (g)).

The detection operation of the device of the present invention having the above structure will be described with reference to the time chart of FIG.
1a repeats the transmission of the ultrasonic wave Ps at the transmission repetition period To set in the internal counter 9 as shown in FIG. 3 (a). When the ultrasonic sensor 1a emits the ultrasonic wave Ps, the delay circuit 11 in the ultrasonic sensor 1a outputs the pulse signal S as shown in FIG. 3 (c) after a predetermined delay time T ₁ . This pulse signal S is given to the ultrasonic sensor 1b of the next order, and the ultrasonic sensor 1b receiving this pulse emits an ultrasonic wave Ps as shown in FIG. 3 (d). Similarly, the ultrasonic sensor 1b outputs the pulse signal S after the delay time T _{1 has} elapsed as shown in FIG. 3 (f), and the ultrasonic sensor 1c of the next order receiving this outputs the third pulse signal S.
Ultrasonic waves are emitted as shown in FIG.

In this way, each ultrasonic sensor 1a, 1b, 1c has a delay time T ₁
The ultrasonic waves Ps are radiated toward the respective detection points one after another at time intervals of. Therefore, each ultrasonic sensor has a third
As shown in Figures (b), (e) and (h), the reflected waves from the vehicle 2a or 2b, which is the detected object, within the "open" time of each gate.
The vehicle is detected as in the conventional case by determining whether Po has been received.

In the above, as shown in FIG. 2 now, even if the ultrasonic wave radiated by the ultrasonic sensor 1a hits the spherical surface portion of the vehicle 2a or the like and is input as the wraparound wave P to the adjacent ultrasonic sensor 1b,
Since the ultrasonic sensor 1b starts its detection operation after a predetermined delay time T ₁ has passed after the ultrasonic sensor 1a radiates the ultrasonic wave Ps, the wraparound wave P generated by the ultrasonic sensor 1a has the next order. It is received before the gate of the ultrasonic sensor 1b is opened.

Therefore, even if the wraparound wave P is adjacent to the ultrasonic sensor
Even if the ultrasonic wave is received by the ultrasonic wave sensor 1b, it does not affect the ultrasonic wave sensor 1b, and the adjacent ultrasonic wave sensors malfunction due to the wraparound wave.

The transmission repetition period To and the delay time T ₁ described above are
Needless to say, it can be adjusted according to the installation conditions such as installation height of ultrasonic sensor, installation interval, height of the object to be detected, etc., and it can be applied at any place by adjusting To and T _1. Is.

In the above example, the ultrasonic sensor 1 is used for convenience of explanation.
The case where each delay time of a, 1b, 1c is set as the same time T ₁ is shown, but it is not possible to freely set the length of the delay time T ₁ for each ultrasonic sensor according to the installation conditions. Of course. Further, in FIG. 2, the pulse switching switch 7 of the parent ultrasonic sensor 1a is also set to the "child" side, and the pulse signal corresponding to the transmission repetition period To from the external pulse device is set to the pulse input terminal 8 thereof. Is also applicable.

The ultrasonic sensor of FIG. 1 described in detail above is configured to immediately emit the ultrasonic wave Ps when the pulse signal S from the outside is input, but instead of this, the ultrasonic sensor of FIGS. 4 (a) to (d) is used. After the signal S from the outside is input as shown, the specified delay time
The ultrasonic wave Ps and the pulse signal S may be simultaneously output after the lapse of T ₁ . In this case, for example, the first
At the input terminal position of the transmitter circuit 4 in the figure, another switch 7 that can be switched to "parent" or "child" is attached.
The input terminal of the transmitting circuit 4 may be switched and connected from the output terminal of the counter 9 to the output terminal side of the delay circuit 11 when is switched to the "child" side.

EFFECT OF THE INVENTION The device of the present invention has the above-described configuration and operation, emits ultrasonic waves by sequentially shifting the ultrasonic wave emission times of the ultrasonic sensors provided corresponding to the adjacent detection points by a predetermined time. Since the object detection operation of the ultrasonic sensor is configured to be performed by shifting by a predetermined delay time, even if a wraparound wave from an adjacent ultrasonic sensor is incident, it does not cause a malfunction and the ultrasonic sensor is installed. The present invention has an excellent effect that the presence of a near object can be accurately detected in any place without being affected by the installation conditions such as height, installation interval, and height of the object to be detected.

Further, the ultrasonic proximity object detection device according to the present invention is configured to emit an ultrasonic wave in accordance with a pulse signal given from the outside, and at the same time, to output a pulse signal after a predetermined delay time set in advance, The ultrasonic proximity object detection device according to the present invention can be realized very simply by simply connecting the pulse signals of the upper ultrasonic sensor to the pulse input terminals of the lower ultrasonic sensor according to the predetermined operation order. Further, since a sequential drive circuit that outputs via a delay circuit is provided for each of the ultrasonic sensors connected in series, even if the ultrasonic sensors are increased or decreased according to the number of detection points, a special drive circuit is provided. This has an excellent effect that it is not necessary to increase or decrease the sequential drive circuit.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of an ultrasonic sensor constituting the ultrasonic proximity object detection device of the present invention, FIG. 2 is a block diagram showing the configuration of the device of the present invention, and FIG.
(I) is a time chart for explaining the operation of the device of the present invention, FIGS. 4 (a) to 4 (d) are time charts of the ultrasonic sensor of the device of the present invention having other configurations, and FIG. FIG. 6 (a) is a block diagram showing the configuration of a sound wave type object detection method.
(B) is a time chart for explaining the operation of the conventional ultrasonic sensor. 1a, 1b, 1c: ultrasonic sensor, 2a, 2b: vehicle (object to be detected),
6: pulse circuit, 8: pulse input terminal, 9: counter, 10: pulse output terminal, 11: delay circuit, To: transmission repetition period,
T ₁ : delay time, Ps: radiated ultrasonic wave, Pr: road surface reflected wave, Po: reflected wave from the detected object, P: wraparound wave, S: pulse signal.

Claims (2)

[Claims] 1. An ultrasonic sensor comprising a plurality of ultrasonic sensors provided corresponding to a plurality of adjacent detection points, said ultrasonic sensors being connected in series, and each ultrasonic sensor being provided with a delay circuit. , Each ultrasonic sensor receives a pulse signal input from the outside and radiates the ultrasonic wave toward the corresponding detection point, and after the ultrasonic wave is radiated through the delay circuit, pulse is generated after each predetermined delay time. An ultrasonic proximity object detection device, characterized in that the ultrasonic wave proximity object detection device is configured to output a signal to a subsequent ultrasonic sensor and sequentially emit ultrasonic waves from each ultrasonic sensor at intervals of respective delay times. 2. An ultrasonic sensor comprising a plurality of ultrasonic sensors provided corresponding to a plurality of adjoining detection points, said ultrasonic sensors being connected in series, and each ultrasonic sensor being provided with a delay circuit. , Each ultrasonic sensor receives a pulse signal input from the outside, and emits an ultrasonic wave toward a corresponding detection point after a predetermined delay time through the delay circuit, and at the same time, outputs the pulse signal to the ultrasonic sensor in the subsequent order. An ultrasonic proximity object detection device, which is configured to output and sequentially emit ultrasonic waves from each ultrasonic sensor at intervals of respective delay times.