JPH05253211A - Human body sensing device - Google Patents

Abstract

PURPOSE:To distinguish person from object certainly by installing piezo element on a seat or bed, calculating at unit time intervals the rate of emergence at which the output signal from piezo element exceeds a certain specified value, and thereupon judging if the seat, etc., is occupied. CONSTITUTION:When a person is seated, a piezoelectric element 1 installed on a seat 6 defroms, and the voltage generated by piezoelectric effect is filtrated by a filter 2, amplified by an amplifying means 3, and smoothened by a smoothening means 4. First comparing means 7 compares the output V of the smoothening means 4 with a predetermined value Va and emits Hi-signal if V>=Va and a Lo-signal if V<Va. The first comparing means 8 calculates the rate of emergence per unit time of Hi outputs given by this first comparing means 7, while the second comparing means 9 emits Hi if the rate of emergence per unit time exceeds the second preset value and emits a Lo binary signal if below the second preset value. It is judged as occupied if this output is Hi and as not occupied if Lo.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a human body detecting device for detecting the presence or absence of a human body on a seat or bedding.

[0002]

2. Description of the Related Art The inventor has heretofore used this type of human body detecting means.
For example, since the human body is detected by a micro switch, an infrared sensor, or an ultrasonic sensor installed in the seat, even when an object is placed on the seat, the switch is turned on by the load or the operation of the person placing the object. Considering that there was a problem of erroneously detecting the human body by detecting changes in infrared rays and ultrasonic waves caused by, the application of a human body detection device that reliably distinguishes humans from objects in order to solve this problem went.

FIG. 6 is a block diagram of a human body detecting device applied to the seating detection of the human body shown at that time. When the human body is seated, the piezoelectric element 1 arranged on the seat 6 is deformed by the body motion of the human body, and a voltage is generated by the piezoelectric effect. A specific frequency component of the output signal of the piezoelectric element 1 is filtered by the filter 2, amplified by the amplification means 3, and smoothed by the smoothing means 4. FIG. 2 shows an output signal waveform of the smoothing means 4 at the time of actual seating. As shown in FIG. 2, in the case of coarse body movement such as sitting, limb movement, and sitting, the movement is over the whole body, so that the piezoelectric element 1 is greatly deformed and a large signal waveform is output from the smoothing means 4. When the person is in a resting state, a relatively low level signal such as the portion S1 in FIG. 2 is output due to minute body movements of the body propagated by the activity of the heart and the respiratory activity of the human body. Further, when an object is placed on the seat 6 as shown in FIG. 2, a large output is obtained immediately after the object is placed, but since the object does not have the heart activity and the respiratory activity as described above, the S1 part of FIG. There is no such output. Based on such an output signal, the determination means 5 determines that a person is seated if the output V from the smoothing means 4 is equal to or higher than Va in FIG. If it is absent, it is determined to be absent. That is, the piezoelectric element 1 arranged on the seat 6 detects minute body movements of the body propagated by the activity of the heart and the respiratory activity of the seated person in a resting state, and the case where an object is placed The distinction was made and the presence of the human body was detected. Va can be determined by obtaining the lowest level of S part in a subject experiment.

[0004]

However, in the human body detection device of the above technique, minute body movements of the body due to the activity of the heart or respiratory activity are not easily propagated to the piezoelectric element 1 depending on the sitting position of the person and personal attributes. However, there is a practical problem that the output V of the smoothing means 4 becomes less than Va even if a person is present, and the absence is determined.

A first object of the present invention is to provide a practical human body detecting apparatus which reduces malfunctions caused by a sitting position of a person and personal attributes. A second object of the present invention is to further improve the detection accuracy.

[0006]

In order to achieve the above object, the present invention provides a piezoelectric element arranged in a seat or bedding and a filter for filtering a specific frequency component of an output signal of the piezoelectric element. Comparing the output signal of the smoothing means with a predetermined first set value; an amplifying means for amplifying the output signal of the filter; a smoothing means for smoothing the output signal of the amplifying means; And a first computing means for computing a rate of appearance of each binary signal output from the first comparing means per unit time; The output signal of the first computing means is compared with a predetermined second set value to determine Hi and Lo of 2
And a second comparing means for outputting a value signal.

According to the present invention, the second calculating means calculates the appearance rate of each binary signal output from the second comparing means per a predetermined set time, and the output of the second calculating means. It comprises a third comparing means for comparing the signal with a predetermined third set value and outputting a binary signal of Hi and Lo.

[0008]

The present invention operates as follows with the above construction. When the human body is seated, the piezoelectric element arranged on the seat is deformed by the body movement of the human body, and a voltage is generated by the piezoelectric effect. A certain frequency component of the output signal of the piezoelectric element is filtered by the filter and amplified by the amplification means,
It is smoothed by the smoothing means. The first comparison means outputs a binary signal of Hi if the output signal of the smoothing means is equal to or larger than a predetermined first set value, and Lo if it is less than the predetermined first set value. The first calculating means calculates the appearance rate per unit time of each of the binary signals output from the first comparing means. The second comparing means outputs a binary signal of Hi if the output signal of the first computing means is equal to or larger than a predetermined second set value, and Lo if it is less than the preset second set value. If this output is Hi, it means that a human body is present.

Further, according to the present invention, the second operation means provides a second operation.
The appearance rate per preset time of each of the binary signals output from the comparing means is calculated, and the output signal of the second calculating means is predetermined by the third comparing means to the third setting. If the value is greater than or equal to the value, Hi, and if less
The binary signal of is output. If this output is Hi, it means that a human body is present.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram of a human body detection apparatus when the present embodiment is applied to human body seating detection. In FIG. 1, 1
Is a piezoelectric element, 2 is a filter, 3 is amplification means, 4 is smoothing means, 7 is first comparing means, 8 is first computing means, and 9 is
Is a second comparing means. The piezoelectric element 1 is formed by forming a polymer piezoelectric material such as polyvinylidene fluoride (PVDF) into a thin film and attaching a flexible electrode film on both sides to form a tape. Here, the piezoelectric element 1 is arranged under the seat cloth of the seat 6. is doing.

The operation of the configuration of the above embodiment will be described below. Piezoelectric element 1 disposed on seat 6 when a human body is seated
Is deformed by the movement of the human body, and a voltage is generated by the piezoelectric effect. A specific frequency component of the output signal of the piezoelectric element 1 is filtered by the filter 2, amplified by the amplification means 3, and smoothed by the smoothing means 4. FIG. 2 shows an output signal waveform of the smoothing means 4 at the time of actual seating. Figure 2
In the case of coarse body movement such as sitting, limb movement, and sitting, the movement is over the whole body, so the piezoelectric element 1 is greatly deformed and a large signal waveform is output from the smoothing means 4, but the seated person is in a resting state. If maintained, the output of a comparatively low level as shown by S1 portion in FIG. 2 is produced due to the minute body movement of the body propagated by the activity of the human heart and the respiratory activity. Also,
When an object is placed on the seat 6 as shown in FIG. 2, a large output is obtained immediately after the object is placed, but since the object does not have the above-described cardiac activity and respiratory activity, it is similar to the S1 part in FIG. There is no output. Based on such an output signal, the first comparison means 7
2 outputs a binary signal of Hi when the output V from the smoothing means 4 is Va or more in FIG. 2 and Lo when V is less than Va.

[0012] Here, there are cases where minute body movements of the body due to heart activity and respiratory activity are difficult to propagate to the piezoelectric element 1 depending on the sitting position of the person and personal attributes. Also, as shown in FIG. 3, the output V of the smoothing means 4 is V
There was a practical problem that it was less than a and the absence was determined. The operation of this embodiment for solving this problem will be described with reference to FIG. In FIG. 3, V is the output of the smoothing means 4, X1 is the output of the first comparing means 7, and Y1.
Represents the output of the first calculating means 8 and X2 represents the output of the second comparing means 9. In FIG. 3, the first comparison means 7 compares the output V of the smoothing means 4 with Va, and if V ≧ Va, then H
If i, V <Va, the Lo signal is output. The first calculation means 8 calculates the appearance rate Y1 of the Hi output output from the first comparison means 7 per unit time To. Second
In the comparison means 9 of Y, Y1 is the second set value Y determined in advance.
A binary signal of Hi is output if a or more, and a Lo signal of Lo is output if less than a. If this output is Hi, then seated, L
If it is o, it means that the person is absent. In the case of FIG. 3, for example, Y1 <Ya is absent at times t0 to t1 and t1 to t2, and absent, and Y1 ≧ Ya is determined at times t3 to t4 and t4 to t5, so that it is determined to be present. Va and Ya can be determined by a subject experiment, but a setting changing means that can manually change the setting may be provided.

Due to the above-mentioned action, minute body movements of the body propagated by the activity of the heart and the respiratory activity in the resting state of the seated person depending on the sitting position of the person and personal attributes, are piezoelectric elements 1.
Even if there is a case where it is difficult to propagate to the user, since the appearance rate at which the output signal from the piezoelectric element 1 becomes a certain set value or more is calculated for each unit time and the presence of the person is determined, the presence or absence of the person is determined without malfunction. There is an effect that you can.

A second embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment in that the second appearance means calculates the appearance rate of each binary signal output from the second comparing means 9 per a predetermined set time.
2 of Hi and Lo by comparing the output signal of the second calculating means 10 and the third setting value determined in advance.
It has a third comparison means 11 for outputting a value signal.

Here, in the first embodiment, it is determined whether the person is absent or seated based on the size of Y1 and Ya. However, the minute body of the seated person is determined by the sitting position of the person and personal attributes. Motion may be hardly transmitted to the piezoelectric element 1, and Y
Even if I experimentally obtained a, Y1 <
There is a problem that it becomes Ya and is judged to be absent. The operation of this embodiment for solving this problem is shown in FIG.
It will be explained based on. In FIG. 5, V is the output of the smoothing means 4, X1 is the output of the first comparison means 7, and Y1 is the first.
The output of the calculation means 8 of X, the output of the second comparison means 9 is X2,
Y2 represents the output of the second calculating means 10, and X3 represents the output of the third comparing means 11. In FIG. 5, the first comparison means 7
Then, the output V of the smoothing means 4 is compared with Va, and V ≧ Va
If so, a Hi signal is output, and if V <Va, a Lo signal is output.
The first calculation means 8 calculates the appearance rate Y1 of the Hi output output from the first comparison means 7 per unit time To. The second comparison means 9 outputs a binary signal of Hi when Y1 is equal to or larger than a predetermined second set value Ya, and Lo when it is less than Y2. Next, the second calculating means 10 calculates the appearance rate Y2 of the Hi output output from the second comparing means 9 per a predetermined set time T1. Third
The comparison means 11 compares Y2 with a predetermined third set value Yb, and outputs Hi when Y2 ≧ Yb, and outputs Lo when Y2 <Yb. The final seating decision is the third
If the output of the comparison unit 11 is Hi, the person is present, and if Lo is Lo, the person is absent. In the case of FIG. 5, one T1 is composed of five Tos, and, for example, at times t0 to t5, X2 is Lo in all five To periods, and Y2 <Yb is satisfied, so it is determined that there is none. Time t5 to t10, t10 to t1
In No. 5, X2 is Hi for at least three periods out of the five To periods and Y1 ≧ Ya. Va, Ya, and Yb can be determined by a subject experiment, but a setting changing unit that can manually change the setting may be provided.

Due to the above action, even if a small body motion of the body of a person who sits down is hardly propagated to the piezoelectric element 1 due to the sitting position of the person or personal attributes, the piezoelectric element 1 outputs from the piezoelectric element 1 every unit time. Since the appearance rate at which the output signal becomes equal to or higher than a certain set value is obtained and the presence is determined based on the plurality of appearance rates at regular intervals, the effect that the presence determination can be performed more accurately than in the first embodiment is achieved. is there.

The above-mentioned embodiment is an application of the present invention to seating detection, and is generally applied to office chairs, sofas, etc. to manage the working state, to manage the presence of a person at home, etc. Good. It can also be applied as seat management for automobiles, trains, passenger planes, etc. Furthermore, if the present invention is attached to bedding, as bed management at home, hospital, facility, hotel, etc.,
Alternatively, it can be applied as a control input for an air conditioner, lighting, audio equipment, etc. in a bedroom.

[0018]

As described above, according to the human body detecting apparatus of the present invention, the following effects can be obtained.

In other words, depending on the sitting position of a person and personal attributes, there are cases where minute body movements of the body propagated by heart activity and respiratory activity in a resting state of the person are difficult to propagate to the piezoelectric element 1. However, since the appearance rate at which the output signal from the piezoelectric element 1 is equal to or higher than a set value is calculated for each unit time and the presence determination is performed, the presence or absence of a person can be determined without malfunction. ..

Further, since the appearance rate at which the output signal from the piezoelectric element 1 is above a certain set value is obtained for each unit time, and the presence is determined based on the plurality of appearance rates at a constant period, the presence is accurately determined. There is an effect that seat determination can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of a human body detection device according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram of an output signal of a smoothing unit in the same device.

FIG. 3 is a diagram showing a waveform diagram of an output signal of a smoothing means and output results of a first comparing means, a first calculating means and a second comparing means in the same apparatus.

FIG. 4 is a block diagram of a human body detection device according to a second embodiment of the present invention.

FIG. 5 is a waveform diagram of the output signal of the smoothing means in the same apparatus, a first comparing means, a first calculating means, a second comparing means,
The figure which shows the output result of a 2nd calculating means and a 3rd comparing means.

FIG. 6 is a block diagram of a conventional human body detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric element 2 Filter 3 Amplifying means 4 Smoothing means 5 Judging means 6 Seat 7 First comparing means 8 First calculating means 9 Second comparing means 10 Second calculating means 11 Third comparing means

Claims (2)

[Claims] 1. A piezoelectric element disposed on a seat or bedding, a filter for filtering a specific frequency component of an output signal of the piezoelectric element, an amplification means for amplifying an output signal of the filter, and the amplification. Smoothing means for smoothing the output signal of the means, and first comparing means for comparing the output signal of the smoothing means with a predetermined first set value and outputting a binary signal of Hi and Lo. A first calculating means for calculating an appearance rate per unit time of each of the binary signals output from the first comparing means, an output signal of the first calculating means, and a second predetermined signal. 2 of Hi and Lo by comparing with the set value
A human body detecting device comprising a second comparing means for outputting a value signal. 2. A second computing means for computing the appearance rate of each of the binary signals output from the second comparing means per a predetermined set time, and an output signal of the second computing means in advance. 3. A third comparing means for comparing a predetermined third set value and outputting a binary signal of Hi and Lo.
The human body detection device described.