JP3149802B2 - Ultrasonic sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic sensor for transmitting an ultrasonic wave to a monitoring space, detecting a reflected wave thereof, and detecting an intruder in the monitoring space.

[0002]

2. Description of the Related Art A conventional ultrasonic sensor will be described with reference to FIGS. FIG. 4 is a block diagram showing the configuration of the ultrasonic sensor. FIG. 5 is an explanatory diagram of a relationship between a data string and background compressed data or detected compressed data. 6 to 8
FIG. 4 is an image diagram illustrating a state in which data acquired by an ultrasonic sensor is stored in a memory.

An ultrasonic sensor transmits an ultrasonic wave of a predetermined frequency into a monitoring space, and detects the presence of an object by receiving a reflected wave from the object in the monitoring space. The monitoring space is the space where the transmitted ultrasonic wave can be received when the reflected ultrasonic wave is reflected by an object that has entered the monitoring space, and the ultrasonic sensor can detect the intruding object. It is.

In FIG. 4, an ultrasonic sensor includes an oscillating unit 1,
Transmission interval determination unit 2, waveform generation unit 3, ultrasonic transmission unit 4a,
Ultrasonic wave receiving section 4b, amplifying section 5, detecting section 6, central processing section 7
And

The oscillating unit 1 generates a transmission signal S1 having an electric continuous vibration and outputs the signal to the waveform generating unit 3.

The transmission interval determination unit 2 determines the transmission interval of the ultrasonic waves, and outputs a transmission instruction signal S2 to the waveform generation unit 3 at predetermined time intervals T.

[0007] Upon receiving the transmission instruction signal S2, the waveform generator 3 generates a tone burst wave S based on the transmission signal S1.
3 and outputs the tone burst wave S3 to the ultrasonic wave transmitting unit 4a for a certain period of time, for example, 1 millisecond.

[0008] The ultrasonic wave transmitting section 4a generates a tone burst wave S
The ultrasonic wave S4 based on No. 3 is transmitted to the monitoring space. When the tone burst wave S3 is input, for example, for 1 millisecond, the ultrasonic transmitting unit 4a transmits the ultrasonic wave S4 for only 1 millisecond. The time interval at which the ultrasonic wave transmitting unit 4a transmits the ultrasonic wave S4 is a predetermined time T.

The ultrasonic wave receiving section 4b receives the ultrasonic wave S5 transmitted by the ultrasonic wave transmitting section 4a and reflected by an object existing in the monitoring space, and generates a received signal S6 which is a weak voltage. The signal is output to the amplifier 5.

The amplifying section 5 amplifies the received signal S6 having a weak voltage to obtain an amplified signal S7 having a voltage of, for example, 0 to 5 [v], and outputs the amplified signal S7 to the detecting section 6.

When receiving the amplified signal S7, the detector 6 sets Low (0 [v]) or High (5 [V]) with a predetermined threshold value.
[V]) The detection signal S8 is output to the central control unit 7 as the detection signal S8.

The central processing unit 7 includes a background compressed data storage unit 7a corresponding to a storage unit, a detected compressed data storage unit 7b corresponding to a storage unit, a writing unit 7c, and a comparison unit 7d. . The central processing unit 7 has two modes, a background setting mode and an operation mode.

The writing unit 7c outputs a low (0 [v]) or a high (5 [V]) of the detection signal S8 every 0.16 milliseconds, for example.
Based on [v]), a data string composed of configuration data of “0” or “1” is generated. The writing unit 7c divides each of the constituent data of the data string into a predetermined number K, for example, every six, and compresses the predetermined number K of the constituent data to form one background compressed data Db or the detected compressed data Ds. Generate. The storage unit 7c writes the background compressed data Db or the detected compressed data Ds into the background compressed data storage unit 7a and the detected compressed data storage unit 7b sequentially from the top of the memory. Therefore, the background compressed data storage unit 7a and the detected compressed data storage unit 7b store and store the background compressed data Db or the detected compressed data Ds, and generate the background compressed data sequence or the detected compressed data sequence corresponding to the compressed data sequence. Is done.

More specifically, the writing section 7c divides the configuration data into a predetermined number K, and
If there is at least one configuration data of "1", the background compressed data Db or the detected compressed data Ds to be written to the memory is set to "1", and if all of the predetermined number K of detected signals S8 are "0", they are written to the memory. The background compressed data Db or the detected compressed data Ds is set to “0”.

Therefore, as shown in FIG. 5, for example, when taking out twelve pieces of continuous configuration data Dc and considering them, of the 12 pieces of configuration data Dc, the fourth to ninth configuration data are " In the case of "1", the background compressed data Db or the detected compressed data Ds is set to "1" based on the six leftmost constituent data Dc, and the remaining six constituent data Dc are set.
Based on c, the background compressed data Db or the detected compressed data Ds is set to “1”. Therefore, two pieces of background compressed data Db or detected compressed data Ds of “1” are written in the background compressed data storage unit 7a or the detected compressed data storage unit 7b.

The writing section 7c compresses the data string at the same time as the waveform generating section 3 outputs the tone burst wave S3 to the ultrasonic wave transmitting section 4a or after a predetermined time, and compresses the data string to generate background compressed data Db.
Alternatively, an operation of writing the detected compressed data Ds into the background compressed data storage unit 7a or the detected compressed data storage unit 7b is started, and 1
After the writing is continued for a certain period of time such as 0 millisecond, the operation ends. The writing unit 7c writes the background compressed data Db or the detected compressed data Ds into the background compressed data storage unit 7a or the detected compressed data storage unit 7b as described above, and generates the background compressed data sequence or the detected compressed data sequence. .

The background compressed data storage section 7a stores background compressed data Db based on a data string sampled in a background setting mode such as an initial setting of the ultrasonic sensor.

The detected compressed data storage section 7b stores detected compressed data Ds based on a data sequence sampled in the operation mode of the ultrasonic sensor.

FIG. 6 is a diagram for explaining the state of the memory of the background compressed data storage unit 7a or the detected compressed data storage unit 7b and the storage contents. In FIG. 6, the leftmost cell M1
Represents a memory for storing the background compressed data Db and the like received between 0 ms and 1 ms, and a cell M2 on the right thereof stores the background compressed data Db received between 1 ms and 2 ms.
b, etc., and a cell M3 on the right further represents a memory for storing background compressed data Db, etc. received during 2 to 3 milliseconds, and so on. Corresponds to the memory that stores the background compressed data Db and the like received. The cell is actually one of the memories
It is represented by bits, and can store “0” or “1”. Then, for example, "1" is assigned to the third cell M3 from the left.
Is written, it means that a time of 2 to 3 milliseconds is required from the transmission of the ultrasonic wave S4 to the reception of the ultrasonic wave S5. The hatched cells in FIG. 6 represent “1”, and the white cells represent “0”.

As described above, the background compressed data Db or the detected compressed data Ds is, as described above, from the transmission of the ultrasonic wave S4 to the reception of the ultrasonic wave S4 depending on the position of the cell in which "1" is stored. Represents the time. Therefore, by multiplying the time by the sound speed, the reciprocating distance from the ultrasonic sensor to the object reflecting the ultrasonic wave S4 can be obtained. The time from when the ultrasonic wave is transmitted until it is received is not stored as a numerical value, but the detection signal S8 input in a time series is bundled and the background compressed data Db composed of "0" and "1" is detected or detected. The reason why the compressed data Ds is stored is that the background compressed data Db or the detected compressed data Ds can be subjected to AND processing and comparison processing so as to improve robustness against noise and facilitate arithmetic processing. It is.

The comparing section 7d is provided with a background compressed data storage section 7a.
And the detected compressed data sequence stored in the detected compressed data storage unit 7b are read out, and the two are compared. If there is a difference between the two, it is determined that there is an intruder in the monitoring space. to decide.

The ultrasonic sensor configured as described above operates as follows. First, in the background setting mode at the time of the initial setting, the ultrasonic wave transmitting unit 4a transmits the ultrasonic wave S4, the ultrasonic wave receiving unit 4b receives the ultrasonic wave S5, and the writing unit 7c detects the detection signal. The data string based on S8 is compressed to generate background compressed data Db, and the background compressed data Db is written to the background compressed data storage unit 7a. At this time, for example, as shown in FIG. 6, the background compressed data Db of “1” is written in the ninth cell M4 and the tenth cell M5 from the left. That is, in the example of FIG. 6, at the time of the initial setting, it takes 8 milliseconds to transmit the ultrasonic wave S4 from the ultrasonic sensor and receive the reflected ultrasonic wave S5.

Next, in the operation mode, the ultrasonic wave transmitting section 4a transmits the ultrasonic wave S4 every predetermined time T, the ultrasonic wave receiving section 4b receives the ultrasonic wave S5, and the writing section 7c. Detection signal S
8 to generate detected compressed data Ds, and stores the detected compressed data Ds in the detected compressed data storage unit 7.
Write to b. At this time, if an intruder exists in the monitoring space and the distance between the ultrasonic sensor and the object that reflects the ultrasonic wave S4 decreases, as shown in FIG. 7, the eighth cell M6 and the ninth cell M7 from the left. Is written with the detected compressed data Ds of "1". That is, in the example of FIG. 7, it takes 7 milliseconds to transmit the ultrasonic wave S4 from the ultrasonic sensor and receive the reflected ultrasonic wave S5.

Next, the comparing section 7d reads the background compressed data string stored in the background compressed data storage section 7a and the detected compressed data string stored in the detected compressed data storage section 7b, and reads both of them. The arrangement of “0” and “1” is compared. If there is a difference between the two, the comparing unit 7d determines that there is an intruder in the monitoring space. When the background compressed data string in FIG. 6 is compared with the detected compressed data string in FIG. 7, the background compressed data string is “000000001100...”, Whereas the detected compressed data string is “000000011000. Are different, the comparing unit 7d determines that there is an intruder. The ultrasonic sensor detects an intruder as described above.

[0025]

However, the ultrasonic sensor as shown in FIG. 4 has the following problems.

Although the constituent data is generated at intervals of 0.16 milliseconds, the writing unit 7c compresses the constituent data to generate the background compressed data Db and the detected compressed data Ds. Since the data is written in the storage unit 7a and the detected compressed data storage unit 7b, the distance resolution is reduced as compared with the case where the data string before compression is used.

That is, when the detection is performed using the data string composed of the configuration data generated every 0.16 milliseconds, the distance represented by one configuration data is 0.16 milliseconds × about 340 meters and about 5 0.4 cm.

However, for example, if the background compressed data Db and the like are stored every millisecond by bundling six constituent data, the distance represented by one bit is 1 millisecond × about 340 meters and about 34 centimeters. It is. That is, the distance resolution is reduced to about one sixth compared with the case where the data string before compression is used.

Also, as shown in FIG. 8, the timing when the configuration data actually becomes "1" is different from that in the case shown in FIG. 7, but when the data sequence is compressed and viewed as a background compressed data sequence or the like. May look the same,
Changes may not be detected.

For this reason, there is a problem that the distance resolution is low and the intrusion of an intruder cannot be reliably detected.

On the other hand, in order to solve this problem, it is conceivable to store all the data strings. However, a large amount of memory is required, and the number of operations in the comparison unit 6 is large, so that a high-performance An arithmetic unit is required, resulting in an increase in cost.

The present invention has been made in order to improve the above-mentioned problems, and an object of the present invention is to increase the distance resolution without significantly increasing the memory, and to increase the distance resolution in a monitoring space due to the intrusion of an intruder. It is an object of the present invention to provide an ultrasonic sensor capable of reliably detecting a change in the temperature.

[0033]

According to the present invention, in order to solve the above-mentioned problems, according to the first aspect of the present invention, a reflected wave is detected after transmitting an ultrasonic wave, and based on the reflected wave. To generate a compressed data string by compressing the data string, and comparing the compressed data string with a compressed data string when no intruder exists in the monitored space, to detect the intrusion in the monitored space. In the ultrasonic sensor that detects the presence / absence of an object, a partial data sequence that is a data sequence before compression of a portion corresponding to the configuration data representing that a reflected wave has been received among the individual configuration data configuring the compressed data sequence A detailed storage unit for storing, a compressed data sequence of a data sequence detected by transmitting ultrasonic waves at a predetermined transmission interval and a partial data sequence thereof, and a compression when no intruder exists in the monitoring space. Data string and its partial data A comparator for comparing the column, is characterized in that it has a.

[0034]

1 to 3 show an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the ultrasonic sensor. FIG. 2 and FIG. 3 are image diagrams for explaining how data obtained by the ultrasonic sensor is stored in the memory. In FIG. 1, the same parts as those of the ultrasonic sensor described in the above-described conventional technique are denoted by the same reference numerals, and detailed description of the same parts will be omitted.

The ultrasonic sensor according to the present embodiment shown in FIG. 1 is different from the ultrasonic sensor described in the above-mentioned conventional technique in that it has the following features.

That is, if at least one of the predetermined number K of constituent data to be compressed exists, the writing unit 8 determines whether the background compressed data Db or the detected compressed data Ds is present.
Is written to the background compressed data storage unit 7a or the detected compressed data storage unit 7b as "1", and the contents (that is, "0" or "1") of each of the predetermined number K of constituent data are written. A background partial data storage unit 10a or a detected partial data storage unit 10 corresponding to a detailed storage unit as a background partial data sequence or a detected partial data sequence corresponding to the partial data sequence.
b. When both of the background compressed data Db and the detected compressed data Ds are “1” when comparing the background compressed data Db and the detected compressed data Ds, the comparing unit 9 further compares the background partial data sequence with the detected partial data sequence, and the two match. This is a configuration in which it is determined whether or not the comparison is made.

As shown in FIG. 2, the background partial data storage unit 10a and the detected partial data storage unit 10b are provided with a partial memory in the background compressed data storage unit 7a and a partial memory in the detected compressed data storage unit 7b. Memory is used. Note that the background partial data storage unit 10a and the detected partial data storage unit 10b
May be provided separately from the background compressed data storage unit 7a and the detected compressed data storage unit 7b.

The ultrasonic sensor constructed as described above operates as follows. First, in the background setting mode at the time of the initial setting, the ultrasonic wave transmitting unit 4a transmits the ultrasonic wave S4,
The ultrasonic wave receiving unit 4b receives the ultrasonic wave S5, and the writing unit 8 compresses a data sequence based on the detection signal S8 into the background compressed data Db, and stores the background compressed data Db in the background compressed data storage unit. Write to 7a. At this time, for example, as shown in FIG. 2, the data string is "... 000001111110 ...".
For example, the background compressed data Db of “1” is added to the eighth cell M8 and the ninth cell M9 from the left.
Is written. Further, since the background compressed data Db stored in the eighth cell M8 is “1”, the writing unit 8
When writing the background compressed data Db, the corresponding configuration data is set as a background partial data string in the background partial data storage unit 1.
Write to 0a. Further, since the background compressed data Db stored in the ninth cell M9 is also “1”, the writing unit 8
When writing the background compressed data Db, the corresponding configuration data is set as a background partial data string in the background partial data storage unit 1.
Write to 0a. Therefore, the background part data storage unit 10a
Stores “000001, 111110”.

Next, in the operation mode, the ultrasonic wave transmitting section 4a transmits the ultrasonic wave S4 at every predetermined time T, the ultrasonic wave receiving section 4b receives the ultrasonic wave S5, and the writing section 7c. Writes the detected compressed data Ds into the detected compressed data storage unit 7b by compressing the data string. At this time, if an intruder exists in the monitoring space, the distance between the ultrasonic sensor and the object that reflects the ultrasonic wave S4 becomes shorter. Then, as shown in FIG. 3, for example, assuming that the data sequence is in the order of "... 0001111111000 ...", for example, the detection compression data Ds of "1" is written in the eighth cell M10 and the ninth cell M11 from the left. It is. Further, since the detected compressed data Ds stored in the eighth cell M10 is “1”, when writing the detected compressed data Ds, the writing unit 8 detects the corresponding configuration data as a detected partial data string. Write to the partial data storage unit 10b. Since the detected compressed data Ds stored in the ninth cell M11 is also “1”, when writing the detected compressed data Ds, the writing unit 8 uses the constituent data as a detected partial data string when detecting the detected compressed data Ds. Write to the storage unit 10b.
Therefore, the detected partial data storage unit 10b stores "0001
11, 111000 "is stored.

Next, the comparison section 9 reads the background compressed data string stored in the background compressed data storage section 7a and the detected compressed data string stored in the detected compressed data storage section 7b, and The two are compared in order from the data stored at the head. If there is a difference between the two, the comparing unit 7d determines that there is an intruder in the monitoring space. Further, the comparison unit 9
Even if there is no difference between them, the background compressed data Db
And both the detected compressed data Ds are “1”,
The background partial data string is read from the background partial data storage unit 10a, and the detected partial data string is read from the detected partial data storage unit 10a.
b, and compares the background partial data string with the detected partial data string. That is, when the comparison unit 9 compares the eighth cells M8 and M10 in FIGS. 2 and 3, the background compressed data Db and the detected compressed data Ds are both “1”. The column and the detection partial data column are read. The background partial data string is “000001” and the detected partial data string is “000111”. Therefore, the comparing unit 9 compares the background partial data string with the detected partial data string, and determines that there is an intruder in the monitoring space because the two are different. The ultrasonic sensor detects an intruder as described above.

Accordingly, the distance resolution can be increased without increasing the memory significantly, and the presence of an intruder can be detected more accurately. Further, since the memory is not increased so much, an increase in cost can be suppressed.

In this embodiment, the configuration data is compressed by setting the detected compressed data Ds and the like to “1” if at least one of the predetermined number of configuration data is “1”.
Detected compressed data D only when all constituent data are "0"
Although s and the like are set to “0”, the compression method is not limited to this. For example, when there are two or more configuration data of “1”, the detection compression data Ds and the like are set to “1”. You may.

[0043]

Since the ultrasonic sensor of the present invention is constructed as described above, according to the first aspect of the present invention, the detailed storage unit stores the reflection data among the individual constituent data constituting the compressed data string. A partial data sequence, which is a data sequence before compression of a portion corresponding to the configuration data indicating that the wave has been received, is stored, and the comparison unit detects that the ultrasonic wave has been transmitted at a predetermined transmission interval. A compressed data sequence of the data sequence and its partial data sequence;
Since the compressed data sequence and the partial data sequence when no intruder exists in the monitoring space are compared, the distance resolution can be increased without increasing the memory much.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of an ultrasonic sensor according to the present invention.

FIG. 2 is an image diagram illustrating a state where data acquired by an ultrasonic sensor is stored in a memory.

FIG. 3 is an image diagram illustrating a state where data acquired by an ultrasonic sensor is stored in a memory.

FIG. 4 is a block diagram showing a configuration of a conventional ultrasonic sensor.

FIG. 5 is an explanatory diagram of a relationship between a data string and background compressed data or detected compressed data.

FIG. 6 is an image diagram illustrating a state where data acquired by an ultrasonic sensor is stored in a memory.

FIG. 7 is an image diagram illustrating a state in which data acquired by an ultrasonic sensor is stored in a memory.

FIG. 8 is an image diagram illustrating a state where data acquired by an ultrasonic sensor is stored in a memory.

[Explanation of symbols]

 4a Ultrasonic wave transmitting section 4b Ultrasonic wave receiving section 8 Writing section 9 Comparison section 7a Background data storage section 7b Detection data storage section 10a Detailed storage section 10b Detailed storage section

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-201826 (JP, A) Patent 3057395 (JP, B2) JP-A-8-506656 (JP, A) (58) Fields investigated (Int. G01S ⁷ /52-7/64 G01S 15/00-15/96 G01V 1/00 G08B 13/16

Claims (1)

(57) [Claims] 1. After transmitting an ultrasonic wave, a reflected wave is detected, a data sequence is generated based on the reflected wave, a compressed data sequence is generated by compressing the data sequence, and the compressed data sequence and the monitoring space are generated. The ultrasonic sensor that detects the presence or absence of an intruder in the monitoring space by comparing the compressed data sequence when there is no intruder in the interior of the monitoring space receives reflected waves from the individual constituent data that make up the compressed data sequence. A detailed storage unit for storing a partial data sequence that is a data sequence before compression of a portion corresponding to the configuration data indicating that the wave has been transmitted; and a data sequence detected by transmitting ultrasonic waves at a predetermined transmission interval. An ultrasonic sensor, comprising: a compressed data sequence and its partial data sequence described above, and a comparing unit that compares the compressed data sequence and its partial data sequence when no intruder exists in the monitoring space.