JP2000131289A - Can content residual quantity detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a can content detection device capable of precisely detecting a can content residual quantity from a vibration signal by hammering. SOLUTION: An exciting force applied for hammering a can by a hammer 2 is detected by an exciting force sensor 11, and the ratio thereof to an exciting reference value is determined by a ratio computing unit 15. The sound by hammering the can 1 is detected by a microphone 3, and separated into time series signals in each frequency zone by an analog BPF 5, and the time series signals are rectified, and instantaneous maximum values in each frequency zone are extracted by a peak hold 7. The maximum values are corrected based on the ratio calculated by the ratio computing unit 15, and compared with the pattern of the maximum values of the time series signals in each frequency zone of each content residual quantity level set up beforehand and with the pattern of a vibration reference value by a comparator 10, to thereby detect the content residual quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a remaining amount of a liquid substance in a can made of a hard material.

[0002]

2. Description of the Related Art A conventional content remaining amount detecting device for detecting the remaining amount of a liquid substance in a container such as a can made of a hard material is disclosed in, for example, JP-A-7-333037. 6 is shown. In the drawing, reference numeral 91 denotes a can containing a liquid material as an object, 92 denotes a hitting device that drives a hammer by a motor to hit the can and generate a tapping sound,
Reference numeral 93 denotes a microphone that converts a tapping sound into an electric signal.
Is an amplifier for amplifying the electric signal converted by the microphone 93, and 95 is a broadband pass filter (hereinafter referred to as HPF), which removes a noise component of 200 Hz or less.

Reference numeral 96 denotes an amplifier; 97a, 97b, and 97c, band-pass filters (hereinafter referred to as BPFs). The HPF 95 removes an electric signal from which noise of 200 Hz or less has been removed. Near, 97b is 59 from around 500Hz
In the vicinity of 0 Hz and 97c, only signal components from around 620 Hz to around 680 Hz are passed.

[0004] 98a, 98b, 98c are BPF97
a, 97b, and 97c are level determination circuits that amplify and rectify the electrical signals input from the respective components, compare the level signals with reference voltages for the respective bands, and determine the level of each frequency band. 99 is a level judgment circuit 98a, 98b,
This is a priority determination circuit that comprehensively determines the electrical signal from the electronic signal 98c in consideration of the priority. 100a, 100b,
A display driving circuit 100c displays the light emitting diodes 101a, 101b, and 101c that display the remaining amount according to a signal from the level determination circuit. A striking drive circuit 102 drives the striking device 92. A power supply 103 supplies a voltage to each circuit.

Next, the operation will be described. First, the striking device 93 is driven by the striking drive circuit 102 to strike an object can. The tapping sound generated at this time is detected by the microphone 93 and converted into an electric signal, and the electric signal is amplified by the amplifier 94 to obtain an appropriate gain.
5, a noise component of 200 Hz or less is removed and input to the BPFs 97a, 97b, and 97c.
Signals in each frequency band are extracted and input to the level determination circuits 98a, 98b, 98c for each frequency band,
The signal level for each frequency band is determined. When the remaining amount of the can 91 is almost full, the lowest frequency component is measured around 300 Hz, and when the remaining amount is about 1/2, 400 Hz.
The lowest frequency is measured in the vicinity, and when the remaining amount is almost exhausted, the lowest frequency is measured in the vicinity of 680 Hz, input to the priority determination circuit 99, and the priority determination circuit 99 detects the remaining amount, and the light emitting diodes 101a, 101b , 101
c operates and is displayed according to the remaining amount.

[0006]

As described above, the conventional content remaining amount detecting device shown in FIG. 6 for detecting the remaining amount of a liquid substance in a can made of a hard material is provided by a blow. Only the lowest frequency of the average level within a predetermined time for each frequency band in the signal obtained by converting the generated tapping sound into an electric signal, that is, the frequency that is the main component, is detected, and the remaining content of the can is accurately detected. could not.

In addition, since it is necessary to strike the can accurately, it is necessary to fix the striking device to the can, and it is not possible to sequentially and continuously detect the remaining amount of the contents of a large number of cans. was there.

The present invention has been made to solve the above problems, and has as its object to obtain the following device for detecting the remaining amount of contents of a can. a. The reliability of detection can be improved as compared with the state of vibration generated by the impact and the reference state. b. Inexpensive and high-speed processing is possible. c. Alternatively, it can be downsized and can flexibly respond to changes in conditions. d. Operability can be improved. e. The influence of the variation of the external force applied to the object can be prevented. f. Noise from the surroundings and the effects of noise can be prevented.

[0009]

According to the present invention, there is provided an apparatus for detecting the remaining amount of contents of a can, comprising: signal detecting means for detecting a vibration generated from an object to which an external force is applied as a vibration signal; A converting means for converting a time-series signal for each predetermined frequency band, an extracting means for extracting the maximum value of the time-series signal for each frequency band, and a maximum for the time-series signal for each frequency band corresponding to the remaining content. Reference value storage means for storing a vibration pattern reference value pattern, and comparing means for comparing the maximum value pattern of the time series signal and the vibration reference value pattern for each frequency band to detect the remaining content. It is provided.

[0010] Since the vibration signal is converted into a time-series signal for each of a plurality of frequency bands, and the maximum value in each of the time-series signals is extracted, the frequency resolution of the vibration signal is improved and the sensitivity from the time-series signal is improved. The maximum value can be extracted well. Therefore, it is possible to accurately grasp the characteristics of the loud sound or vibration immediately after the occurrence, which is also the characteristic of the striking sound, and make a comparison.

The converting means is a plurality of band filters for passing frequency components of a predetermined frequency band of the vibration signal, and the extracting means rectifies the frequency components passing through each band filter, and converts the rectified frequency components. The maximum value among the peak values is extracted as the maximum value.

If the conversion means is a bandpass filter, the processing can be performed at a high speed, and the apparatus is simple and inexpensive. In particular, if an analog bandpass filter is used, the processing can be speeded up. If a digital bandpass filter is used, the size can be reduced, and the condition can be flexibly changed. In addition, since the extraction means extracts the maximum value from the rectified frequency components, it can be detected even if the maximum value is present in the negative sign portion of the vibration signal, and can be accurately compared even in the case of an object where the vibration signal rapidly attenuates. .

Further, the conversion means is a wavelet conversion means for performing a wavelet conversion of the vibration signal, and the extraction means extracts the maximum value of the time series signal for each frequency band based on the result of the conversion by the wavelet conversion means.
If the wavelet transform unit is used, the characteristics at the time of separating the signal into time-series signals for each frequency band can be improved, and the reliability of determination can be improved.

The converting means is a short-time fast Fourier transform means for short-time fast Fourier transform of the vibration signal,
The extracting means extracts the maximum value of the time-series signal for each frequency band based on the conversion result by the short-time fast Fourier transform means. The use of the short-time Fourier means improves the frequency resolution.

Further, an external force detecting means for detecting the magnitude of the applied external force is provided, and at least one of a vibration signal, a time-series signal, a maximum value, and a vibration reference value is corrected according to the magnitude of the external force. A correction means is provided.

Correction is made in accordance with the magnitude of the external force to prevent the comparison means from being affected by variations in the magnitude of the external force. Also, for example, by performing different corrections according to the external force for each frequency band, it is possible to compare with high reliability even an object with a complicated structure in which the distribution of frequency components changes according to the applied external force. it can.

Further, an external force detecting means for detecting the magnitude of the applied external force is provided, and at least one of a signal detecting means, a converting means, an extracting means, and a comparing means when the magnitude of the external force exceeds a predetermined value. Command means for commanding the start of operation is provided.

Since the operation is not started until the command is issued, there is no possibility that the surrounding noise, vibration, noise, etc. when there is no command is erroneously processed as a vibration signal. Therefore, the influence of these can be prevented, and the reliability of comparison is improved.

Further, there is provided external force detecting means for detecting the magnitude of the applied external force as an external force signal, ratio calculating means for calculating a ratio obtained by dividing the external force signal by a preset external force reference value, and Correcting means for changing the relationship between the maximum value and the vibration reference value in the comparing means by correcting at least one of the vibration signal, the time-series signal, the maximum value, and the vibration reference value; And a ratio determining means for determining whether or not there is a power supply.

The ratio calculation means determines whether or not the ratio between the external force and the external force reference value is within a predetermined range, that is, whether the external force applied to the object, that is, the exciting force is not too small or too large. It is made clear that an inappropriate external force that is out of this range is applied. If the excitation force is too small or too large, erroneous determination can be prevented, for example, when the frequency characteristics of the vibration generated by the object are different. If it is known that an inappropriate external force has been applied, the external force may be applied again, so that the operation can be performed without using much nerves, and the operability is improved.

Further, there are provided external force signal amplifying means for amplifying the external force signal and outputting it as an amplified external force signal, and vibration signal amplifying means for amplifying the vibration signal and outputting it as an amplified vibration signal. It shall be used as an external force signal, the converting means shall use the amplified vibration signal as a vibration signal, and a range over detecting means for detecting that at least one of the peak values of the amplified external force signal and the amplified vibration signal has exceeded a predetermined value. It is characterized by having been provided.

In order to ensure the reliability of the measurement, the fact that the amplified external force signal or the amplified vibration signal exceeds a predetermined value, that is, that a large signal that saturates the external force signal amplifying means or the vibration signal amplifying means is input. To detect.

Further, the present invention is characterized in that automatic gain setting means for automatically setting at least one of the external force signal amplifying means and the vibration signal amplifying means is provided.

The amplification factor can be easily set so that the amplified external force signal and the amplified vibration signal have an appropriate output range.
Operability is improved. Further, a decrease in the S / N ratio can be prevented, and the reliability of the determination is improved.

Further, the vibration reference value is set by dividing the remaining content level of the can into a plurality of parts, hitting each of the divided remaining content levels a plurality of times, and vibrating each of the hits for each frequency band. A signal is obtained, and a vibration reference value for detecting a corresponding remaining content level is set between a maximum value and a minimum value of a maximum vibration signal of a time series signal for each of a plurality of frequency bands.

By setting the vibration reference value as a vibration reference value having a width between the maximum value and the minimum value of the maximum vibration signal of the time series signal for each of a plurality of frequency bands, Even if there is variation, the content remaining level can be easily detected.

Further, a striking means for applying an external force to the can is rotatably supported at an intermediate portion, and has an arm having a ball formed of an elastic body at one end, and an intermediate portion between the arm supporting portion and the ball. A stopper that stops rotation at the position is provided, a spring that pulls in the direction in which the arm abuts the stopper is mounted, and a drive mechanism that pushes down the other end of the arm and opens it is provided. . By using this impact device, the external force applied to the can is stabilized, and the variation in the determination of the airtight state of the can is reduced.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration diagram of a content remaining amount detection device according to the first embodiment. Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG. FIG.
In the figure, 1 is a can of an object, 2 is a hammer of a striking device which strikes the can 1 and generates a hitting sound, 11 is a vibrating force sensor attached to the hammer 2 and converts a vibrating force into an electric signal, and 12 is An amplifier 13 amplifies the electric signal converted by the vibration sensor 11, and a rectifier 13 converts the signal amplified by the amplifier 12 into a direct current.

14 is a peak hold for holding the maximum value of the DC signal output from the rectifier, 15 is a ratio calculator for calculating the ratio between the output of the peak hold 14 and the external force reference value stored in the reference value setting device 16, Reference numeral 17 denotes a trigger detector that detects a trigger from a DC signal output from the rectifier 13.

Reference numeral 19 denotes a ratio judging device for judging the ratio obtained by the ratio calculator 15, and 20 denotes an automatic range setting device for automatically setting the amplification factor of the amplifier 12 from the peak value output from the peak hold 14. . Reference numeral 21 denotes a range over detector which detects an over range from the peak value output from the peak hold 14.

Reference numeral 3 denotes a microphone which is attached to the hammer 2 serving as a hitting device and converts the hitting sound of the hit can into an electric signal. 4 denotes an amplifier which amplifies the electric signal converted by the microphone 3. An analog bandpass filter (hereinafter, referred to as an analog BPF) as a converting means for separating a signal to be obtained for each frequency band. This analog BPF 5 is, for example, a human audible range of 20 Hz to 2 Hz.
31.25Hz-16kHz to cover almost 0kHz
Up to 9 octaves are provided, and a total of 28 bands are provided to give a resolution of 1/3 octave.

Reference numeral 6 denotes a rectifier for rectifying a signal for each frequency band obtained from the analog BPF 5 and converting the signal to DC. Reference numeral 7 denotes a peak hold for holding the maximum peak value of the output from the rectifier 6; A corrector that corrects the peak value output by the peak hold 7 from the given ratio,
Reference numeral 9 denotes a reference value storage means for storing a vibration reference value for each frequency band converted into a time-series signal corresponding to the remaining content level of the can in the following reference value setting mode. A comparator for comparing the pattern of the time-series signal for each band with the pattern of the vibration reference value stored in the reference value storage means 9 to detect the corresponding remaining amount of the content. Reference numeral 18 denotes the content detected by the comparator 10. It is a display for displaying the remaining amount of goods.

31 is a rectifier that does not pass through the analog BPF,
32 is a peak hold for holding the maximum peak value of the output from the rectifier 31; 33 is an automatic range setting device for automatically setting the amplification factor of the amplifier 4 from the peak value output from the peak hold 32; Is an over-range detector that detects over-range from the peak value output from.

Next, a reference value setting mode for setting the reference value of the content remaining level by changing the remaining content level of the can serving as a reference as the operation will be described. The content in the can is divided into a plurality of remaining levels of the content between the full state of the can 1 and the state of no content, and a sound pressure reference value is detected for each remaining level of the content. It shall be stored in the storage means 9 respectively.

In setting the external force detection level, first, the amplification factors of the amplifiers 4 and 12 are minimized. In this state, the can 1 as an object is hit by the hammer 2, the generated hitting sound is converted into an electric signal by the microphone 3, and the maximum value of the hitting sound signal is obtained by the rectifier 31 and the peak hold 32 that do not pass through the analog BPF. . The maximum value is input to the automatic range setting unit 33, and the gain of the amplifier 4 is set so as to have an appropriate measurement range.

Similarly, after the vibration generated in the hammer 2 by the impact is converted into an electric signal by the excitation force sensor 11, the amplifier 1
2. The maximum value of the vibration signal is obtained by the rectifier 13 and the peak hold 14. The maximum value is input to the automatic range setting unit 20, and the gain of the amplifier 12 is set so as to have an appropriate measurement range.

The appropriate measurement range is, for example, corrected by the difference in the excitation force as in the first embodiment. If the range is 1/2 to 2 times, the maximum is 2 compared to the reference value. Since it is necessary to accept twice the input, the signal level input in this reference value setting mode is 5 times the measurement range.
The gain is set to be 0%. In this way, the amplification rate of both the vibration and the sound pressure is set by the first hit in the reference value setting mode.

Next, the can 1 as an object is
To blow. At this time, the vibration generated in the hammer 2 is converted into an electric signal by the excitation force sensor 11, and the amplifier 12 gives the gain set by the first hit in the reference value setting mode. The amplified signal is converted into a direct current by the rectifier 13. The trigger detector 17 compares the DC signal from the rectifier 13 with a preset reference value, and outputs a trigger when the DC signal exceeds the reference value.

The peak hold 14 records the maximum value of the DC signal input from the rectifier 13. At this time, the operation of the peak hold 14 is started by a trigger signal from the trigger detector 17.

The recording of the maximum value is performed for a certain period of time until the vibration generated by the hammer 2 due to the impact is attenuated to some extent, and then the output from the peak hold 14 is stored in the reference value setting unit 16. Next, a method of setting the vibration reference value will be described. A plurality of remaining levels are set between the state of filling of the remaining amount of contents in the can and the minimum detected remaining amount, and the following operation is performed for each remaining amount level to set a sound pressure reference value.

Similarly to the setting of the external force detection level, the sound wave generated by hitting the can is converted into an electric signal by the microphone 3 and the reference value setting mode is set by the amplifier 4 for each remaining content level of the can. Gives the gain set by the first hit of. A plurality of amplified sound pressure signals are provided and input to an analog BPF 5 set to pass different frequency bands, and are separated into time-series signals for each frequency band.

The time series signal separated for each frequency band by the analog BPF 5 is converted into a DC signal by the rectifier 6 and input to the peak hold 7. The recording operation of the maximum value of the DC signal from the rectifier 6 of the peak hold 7 is started by a trigger signal from the trigger detector 17 and is constant until the sound pressure decay of the object as in the case of the peak hold 14 for the excitation force. This is performed for a time, and the instantaneous maximum value of the time-series signal for each frequency band is recorded. After a certain period of time until the sound pressure decay, the pattern of the maximum value of the time-series signal for each frequency band recorded by the peak hold 7 is stored in the reference value storage means 9 corresponding to the remaining level of the contents.

By the operation of the reference value setting mode, the reference value setting device 16 stores the information indicating the strength of the impact, and the reference value storage means 9 stores the information corresponding to the remaining amount level of the contents of the can. Information indicating the instantaneous maximum sound pressure for each sound frequency band is stored.

Next, a detection mode for inspecting an object will be described. First, the can 1 as an object is hit with the hammer 2. At this time, as in the reference value setting mode, the vibration generated in the hammer 2 is converted into an electric signal by the excitation force sensor 11, amplified by the amplifier 12, and converted to DC by the rectifier 13. Similarly, the trigger detector 17 outputs a trigger from the DC signal from the rectifier 13 and
Records the maximum value of the DC signal for a certain period of time from the trigger output to the sound pressure decay.

In the detection mode, the maximum value recorded in the peak hold 14 is input to the ratio calculator 15 after a certain period of time until the sound pressure decay, and the ratio calculator 15 compares the maximum value from the peak hold 14 with the maximum value. The ratio with respect to the reference value stored in the reference value setting device 16 is calculated and output.

Similarly to the reference value setting mode, the sound wave generated by the impact is converted into an electric signal by the microphone 3 and amplified by the amplifier 4, separated into a time series signal for each frequency band by the analog BPF 5, and The signal is converted into a signal and input to the peak hold 7. The peak hold 7 records the maximum value of the DC signal for a fixed time from the trigger output to the sound pressure decay.

In the case of the detection mode, the maximum value recorded by the peak hold 7 is input to the compensator 8 after a certain period of time until the sound pressure decay, and the corrector 8 determines an appropriate value from the ratio obtained from the ratio calculator 15. Calculate the correction value and set peak hold 7
And outputs the corrected value.

At this time, for example, if the vibration level and the sound pressure are corrected in proportion, if the ratio twice as large as the vibration reference value is obtained by calculation, the maximum value recorded in the peak hold 7 is set to 2 Divide by. In other words, if the excitation force in the detection mode is twice as large as the excitation force in the reference value setting mode, the maximum value obtained assuming that the sound pressure at each frequency generated is also doubled. Is divided by 2 so as to be converted into the excitation force in the reference value setting mode.

The maximum value pattern of the time series signal for each frequency band corrected in this way is compared with the pattern of the vibration reference value for each remaining content level stored in the reference value storage means 9 in the comparator 10. The content remaining level of the closest pattern is compared and output to the display 18 as the content remaining level.

Further, when the sound pressure reference value is smaller than the overall sound pressure, a judgment signal is prevented from being erroneously output in a frequency band other than the main component by taking measures such as canceling the comparison on the lower limit side.

The display 18 inputs the remaining contents from the comparator 10 in each frequency band and displays the remaining contents.

The ratio judging device 19 outputs an out-of-correction range alarm when the ratio calculated by the ratio calculator 15 exceeds a predetermined relationship. The predetermined relationship at this time is set to, for example, 1/2 to 2 times. Then, if there is an input less than や or more than twice, an out-of-correction-range alarm is output.

By limiting the range of the correction by the excitation force in this way, it is possible to reliably inspect even an object in which the frequency characteristic of the striking sound generated when the excitation force changes extremely is changed. It is possible to do.

Further, there is provided command means for commanding the start of at least one of the signal detecting means, the converting means, the extracting means and the comparing means when the magnitude of the vibration exceeds a predetermined value in the trigger detector 17. Therefore, the influence of noise or the like from the surroundings can be reduced, and the reliability of determination can be improved.

Furthermore, by starting the operation of the device for detecting the remaining amount of contents in the can by the trigger signal from the trigger detector 17, it is possible to prevent the influence of noise from the surroundings and to improve the reliability of the judgment. it can. Although the trigger signal of the trigger detector 17 is given to the peak holds 14 and 7, the excitation force sensor 11, the amplifier 12,
Similar effects can be obtained by giving the analog BPF 5, the rectifier 6, the compensator 8, the comparator 10 and the like to start the maximum value storage operation or the comparison operation.

In each of the reference value setting mode and the detection mode, the range over detector 21 inputs the peak value obtained from the peak hold 14 for the vibration signal,
An overrange alarm is output when the peak value exceeds a predetermined relationship. The range over detector 34 inputs the peak value obtained from the peak hold 7 for the sound signal,
An overrange alarm is output when the measurement signal exceeds a predetermined relationship.

The predetermined relationship at this time is set, for example, as 99% of the measurement range. In this case, when a signal exceeding 99% is input, an overrange alarm is output.

Further, by setting an appropriate measurement range at the first hit in the reference value setting mode, the trouble of manually setting the measurement range is eliminated, and the operability is improved. Furthermore, if the range is not appropriate when setting manually, the S / N ratio decreases and the reliability of the inspection decreases, but such a problem does not occur because the appropriate range is set automatically. It is possible to obtain a device for detecting the remaining amount of contents of a can with improved detection reliability.

Also, by outputting a range over alarm immediately before the input of each signal is saturated, an erroneous determination due to the saturation of the amplifier is prevented, and a device for detecting the remaining amount of contents in a can with improved reliability of inspection is provided. It is possible to obtain. Note that analog B
The use of the PF enables high-speed detection.

Embodiment 2 In the second embodiment, a digital BPF is used to obtain the maximum value of the time-series signal for each frequency band.
This is an embodiment in the case of using. FIG. 2 shows the configuration. In FIG. 2, reference numeral 51 denotes an A / D converter for converting an analog signal from the rectifier 13 into a digital signal, and reference numeral 52 denotes an A / D converter for converting an analog signal from the amplifier 4 into a digital signal.
It is a D converter. Numeral 53 denotes a maximum value calculator as an extracting means for extracting the maximum value from the digital signal from the A / D converter 51.

Reference numeral 61 denotes a digital BPF as conversion means for converting a digital signal into a time series signal for each frequency band. The digital BPF 61 has a human audible range of 20 to 20,000 Hz, for example, as in the first embodiment of FIG.
In order to cover almost 9 octaves from 31.25 to 16,000 Hz, a total of 28 bands are provided to provide a resolution of 1/3 octave. Reference numeral 62 denotes a rectifier for rectifying the vibration signal from the digital BPF, and reference numeral 63 denotes a maximum value calculator as extraction means for extracting a maximum value from the rectified digital signal.

Reference numeral 64 denotes a corrector, which outputs a correction value obtained by correcting the peak value output from the maximum value calculator 63 based on the ratio obtained from the ratio calculator 15. Reference numeral 65 denotes a comparator as a comparing means, which outputs the output of the compensator 64 and the reference value
6 is compared with the vibration reference value stored. Note that 28 rectifiers 62, peak hold circuits 63, and correctors 64 are provided corresponding to the digital BPFs 61 provided for all 28 bands. 65 is a reference value storage means, 66
Is a comparator.

A maximum value calculator 41 extracts the maximum value from the digital signal from the A / D converter 52 rectified by the rectifier 31. Other configurations are the same as those shown in FIG. 1, and therefore, the same reference numerals are given to the corresponding components, and the description will be omitted.

Next, the operation will be described. First, a reference value setting mode in which the remaining content level of the can serving as a reference is changed to set a vibration reference value for each remaining level will be described. A / D
The converter 51 converts an analog DC signal from the rectifier 13 into a digital signal. At this time, the A / D converter 51
Starts its operation in response to a trigger signal from the trigger detector 17 and continues for a certain period of time until the vibration generated by the hammer 2 due to the impact attenuates to a predetermined value or less. The maximum value calculator 53 extracts the maximum value of the digital signal and stores it in the peak reference value setting device 16 as a peak reference value.

Similarly, the sound wave generated by the impact is converted into an electric signal by the microphone 3, given an appropriate gain by the amplifier 4, and then converted into a digital signal by the A / D converter 52. At this time, the A / D converter 52 starts operating in response to a trigger signal from the trigger detector 17, and operates for a certain period of time until the sound pressure generated by the impact on the target object attenuates below a predetermined value. The converted digital signal is input to 28 digital BPFs 61 set to pass different frequency bands, and is separated into time-series signals for each frequency band.

The time-series signal separated for each frequency band by the digital BPF 61 is converted into a DC signal by the rectifier 62 and input to the maximum value calculator 63. Maximum value calculator 63
Extracts the maximum value of the DC signal, and
5 is stored. In this way, the instantaneous maximum value for each frequency band is extracted and stored in the reference value storage means 65.
By the operation of the reference value setting mode, the reference value setting device 16 stores information indicating the strength of the impact, and the reference value storage means 65 stores the instantaneous maximum sound pressure in each frequency band of the impact sound. Is stored.

Next, a detection mode for detecting the remaining amount of the contents of the can will be described. First, the can 1 as an object is hit with the hammer 2. At this time, similarly to the case of the reference value setting mode, the vibration generated in the hammer 2 is converted into an electric signal by the excitation force sensor 11, amplified by the amplifier 12, and
To convert to DC. Similarly, the trigger detector 17 is connected to the rectifier 1.
The A / D converter 51 converts the DC signal into a digital signal for a certain period of time from the trigger output to the vibration damping. The maximum value calculator 53 extracts and outputs the maximum value of the digital signal.

In the case of the detection mode, the maximum value extracted by the maximum value calculator 53 is input to the ratio calculator 15, and the ratio calculator 15 calculates the maximum value and the peak reference value stored in the reference value setter 16. Calculates and outputs the ratio.

Similarly to the reference value setting mode, the sound wave generated by the impact is converted into an electric signal by the microphone 3, amplified by the amplifier 4, and converted into a digital signal by the A / D converter 52. At this time, the operation of the A / D converter 52 is started by a trigger signal from the trigger detector 17, and is performed for a certain period of time until sound pressure decay. The digital signal is separated into a time series signal for each frequency band by a digital BPF 61, converted into a DC signal by a rectifier 62,
3 is input. The maximum value calculator 63 extracts and outputs the maximum value of the DC signal.

In the case of the detection mode, the maximum value extracted by the maximum value calculator 63 is input to the corrector 64,
Reference numeral 4 calculates an appropriate correction value based on the ratio obtained from the ratio calculator 15, corrects the maximum value obtained from the maximum value calculator 63, and outputs the corrected value. The corrected maximum value pattern for each frequency band is compared with the vibration reference value pattern for each remaining content level stored in the reference value storage means 65 in the comparator 66, and Display 1 indicates the remaining content level corresponding to the value pattern as the remaining content.
8 is output.

As described above, by using the digital BPF 61 as a method of obtaining a time series signal for each frequency band, the size of the apparatus can be reduced, and since the processing is performed by software (S / W), the filter characteristic is changed or the frequency band to be diagnosed is changed. It is possible to flexibly cope with the addition of, for example.

Embodiment 3 FIG. 3 is a configuration diagram of a device for detecting the remaining amount of contents of a can according to the third embodiment. In the third embodiment, a wavelet transform (Wav
This is an embodiment using an elet transform, and will be described with reference to FIG.

In the third embodiment, a wavelet transformer 71 is provided to obtain a time-series signal for each frequency band. Other operations are the same as those in the second embodiment. In the wavelet transform, an effective value is calculated by the analysis operation, so that it is not necessary to provide a rectifier.

In the figure, reference numeral 71 denotes a wavelet transformer (Wavelet Transform) as a conversion means, which separates a digital sound pressure signal into a time series signal for each frequency band by expanding or reducing a basis function (mother wavelet). I do. The signals converted by the wavelet transformer 71 are provided with 28 sets of maximum value calculator 63 and corrector 6
4. Input to the comparator 66. The comparator 66 compares the pattern with the vibration reference value for each remaining content level stored in the reference value storage means 65 in the same manner as that shown in FIGS. The remaining level is output to the display 18 as the remaining content.

At this time, by selecting an appropriate basis function in accordance with the measured waveform and the phenomenon to be observed, the frequency separation characteristics can be improved, and the reliability of determination can be improved. Further, the size of the device can be reduced by using the wavelet transform.

Embodiment 4 FIG. 4 is a configuration diagram of an apparatus for detecting the remaining amount of contents of a can according to the fourth embodiment. Embodiment 4
Is a configuration using short-time FFT to find the maximum value of the time-series signal for each frequency band. The case where the short-time FFT according to the fourth embodiment is used will be described with reference to FIG.
In the fourth embodiment, the short-time FFT calculator 81
Is provided to obtain a time-series signal for each frequency band. Other operations are the same as those in the second embodiment. In the short-time FFT conversion, an effective value is calculated by the analysis operation, and therefore, there is no need to provide a rectifier. In the figure, reference numeral 81 denotes a short-time FFT (ST
FT: Short-Time Fourier-Transform)
A time-series signal for each frequency band is obtained.

The time-series signal for each frequency band by the short-time FFT calculator 81 is input to the maximum value calculator 63 as in the third embodiment, and 28 sets of the maximum value calculator 63 are provided.
It is input to a compensator 64 and a comparator 66. The comparator 66 is
The reference value storage means 65 is the same as that shown in FIGS.
Is compared with the pattern of the vibration reference value for each remaining content level, and the content remaining level of the pattern that matches the most is output to the display 18 as the remaining content. Display 18
Indicates the remaining content level.

As described above, the short-time F which is a Fourier transformer
By providing the FT calculator 81 to obtain a time-series signal for each frequency band, the frequency resolution can be improved.

Therefore, the reliability of the diagnosis can be improved in the case where the characteristics of the change in frequency appear due to the structure of the test object by utilizing the excellent resolution of the short-time FFT. Further, the size of the device can be reduced by using the short-time FFT transform.

Embodiment 5 In the fifth embodiment, the setting of the vibration reference value is performed a plurality of times (for example, about 10 times) on each of the divided remaining levels, and the maximum value of the time-series signal for each of the plurality of frequency bands is calculated. Then, between the maximum value and the minimum value of each of the obtained plurality of time-series signal data is stored as a vibration reference value in the reference value storage unit 66, and the time-series signal of each frequency band at an arbitrary remaining content level is stored. The pattern of the maximum value is compared with the pattern of the vibration reference value stored in the reference value storage means 66, and the remaining content level corresponding to the corresponding vibration reference value is set as the remaining level at the time of detection.

When the configuration in which the remaining content level is set as the sound pressure reference value having a width above and below for each frequency band is applied to the first to fourth embodiments, when the vibration reference value is set, The influence of the difference in the impact condition is reduced, and the accuracy of detecting the remaining content level can be increased.

Embodiment 6 FIG. Embodiment 6 is an embodiment of a hitting means for hitting a can. In the first to fourth embodiments, the inspector hits the can with a hammer.
The magnitude of the impact varies from individual to individual, and may vary depending on the degree of fatigue of the inspector as well as the mood. In the sixth embodiment, an inspection is performed by a hitting device as described below so that the hitting is always constant.

FIG. 5 shows the structure of the hitting device. In the figure, 110 is an arm made of an elastic body, 111 is a ball made of an elastic body, 112 is a rotating shaft that rotatably supports the arm 110, 113 is a stopper that regulates the rotating position of the arm 110, 114 is a spring for applying a rotational force to the arm, 115 is a drive mechanism for pushing down and opening the other end of the arm, and 116 is a gantry.

The ball 111 is formed of an elastic material so as to prevent noise from being produced when the can is hit with a can.
Reference numeral 0 denotes a state in which the ball 111 is attached to one end, and is formed to have appropriate elasticity. Drive mechanism 11
5 is rotated once by a miniature motor, for example, to push down and open the other end 110a of the arm 110,
When the arm 110 is released, it is returned by the pulling force of the spring 114, and the ball 11 hits the can at the moment when the arm comes into contact with the stopper 113.

By using a drive mechanism 115 as a motor, remote control is possible, and a constant impact can be automatically applied to the can. By driving the device for detecting the remaining content of the can using this hitting device, the remaining content of the can can be accurately detected.

In each of the above embodiments, the external force is applied by the hammer. However, the external force is applied by other means, for example, the external force is applied by an electromagnetic coil or a cylinder. Good.

[0087]

Since the present invention is configured as described above, it has the following effects.

Signal detecting means for detecting vibration generated from the can to which an external force is applied as a vibration signal, converting means for converting the vibration signal into time-series signals for each of a plurality of predetermined frequency bands, Extraction means for extracting a value for each frequency band, reference value storage means for storing a pattern of the maximum value of the time series signal for each frequency band corresponding to the remaining content as a vibration reference value, and time series for each frequency band A comparison means for comparing the pattern of the maximum value of the signal with the pattern of the vibration reference value to detect the remaining amount of the content is provided, so that the frequency distribution of the large sound pressure immediately after the occurrence, which is also a characteristic of the tapping sound, is accurately achieved. It can be grasped and the remaining amount of the contents can be accurately detected.

The converting means is a plurality of band filters for passing the frequency components of a predetermined frequency band of the vibration signal. The extracting means rectifies the frequency components passing through each band filter, and converts each of the rectified frequency components. Since the maximum value among the peak values is extracted as the maximum value, if the converting means is a band-pass filter, the processing can be performed at high speed, and the apparatus is simple and inexpensive.
Further, since the extracting means extracts the maximum value from the rectified frequency components, it is possible to detect even when the maximum value is present in the negative sign part of the vibration signal, and to accurately compare even when the vibration signal is rapidly attenuated.

Further, the transforming means is a wavelet transforming means for wavelet transforming the vibration signal, and the extracting means extracts the maximum value for each frequency band based on the result of the conversion by the wavelet transforming means. It is possible to improve characteristics when separating the signals into time-series signals for each frequency, and it is possible to improve the reliability of comparison and determination.

Since the converting means is a short-time fast Fourier transforming means, and the extracting means extracts the maximum value of the time-series signal for each frequency band based on the result of the conversion by the short-time fast Fourier transforming means. Resolution can be improved.

Further, an external force detecting means for detecting the magnitude of the applied external force is provided, and at least one of a vibration signal, a time-series signal, a maximum value, and a vibration reference value is corrected according to the magnitude of the external force. Since it is characterized by the provision of a correction means, by correcting according to the magnitude of the external force,
In the comparison by the comparison means, the influence of the variation in the magnitude of the external force can be prevented, and the reliability of the comparison is improved.

Further, an external force detecting means for detecting the magnitude of the applied external force is provided, and at least one of a signal detecting means, a converting means, an extracting means and a comparing means when the magnitude of the external force exceeds a predetermined value. A command means for commanding the start of operation is provided. Since the operation is not started until a command is issued, the surrounding noise, vibration, noise, etc. when there is no command may be erroneously processed as a vibration signal. There is no. Therefore, the influence of these can be prevented, and the reliability of the determination is improved.

Further, there is provided external force detecting means for detecting the magnitude of the applied external force as an external force signal, and a ratio calculating means for calculating a ratio obtained by dividing the external force signal by a preset external force reference value; Correction means for correcting the relationship between the maximum value and the vibration reference value in the comparison means by correcting at least one of the vibration signal, the time-series signal, the maximum value and the vibration reference value based on the ratio; It is characterized in that it is provided with a ratio determining means for determining whether or not it is within the range. it can.

Further, external force signal amplifying means for amplifying the external force signal and outputting it as an amplified external force signal and vibration signal amplifying means for amplifying the vibration signal and outputting it as an amplified vibration signal are provided. It shall be used as an external force signal, the converting means shall use the amplified vibration signal as a vibration signal, and a range over detecting means for detecting that at least one of the peak values of the amplified external force signal and the amplified vibration signal has exceeded a predetermined value. Since it is characterized in that it has been provided, it is detected that the amplified external force signal or the amplified vibration signal exceeds a predetermined value, that is, it is detected that a large signal is input such that the external force signal amplifying means or the vibration signal amplifying means is saturated. As a result, the reliability of the measurement can be ensured.

[0096] In addition, since amplification factor automatic setting means for automatically setting the amplification factor of at least one of the external force signal amplifying means and the vibration signal amplifying means is provided, the amplified external force signal and the amplified vibration signal are output. The amplification factor can be easily set so as to be in an appropriate output range, and operability is improved.
Further, a decrease in the S / N ratio can be prevented, and the reliability of the determination is improved.

Further, the setting of the vibration reference value is performed a plurality of times for each of the divided remaining levels, and the maximum value of the time-series signal for each of the plurality of frequency bands is calculated. The value between the maximum value and the minimum value of the sequence signal data is stored in the reference value storage means 66 as a vibration reference value, and the maximum value of the time series signal for each frequency band at an arbitrary remaining content level is stored in the reference value storage means. 66 is compared with the vibration reference value stored in 66, and the remaining content level corresponding to the corresponding vibration reference value is configured to be the remaining level at the time of detection. The influence of the difference is reduced, and the detection accuracy of the remaining content level can be increased.

Further, a striking means for applying an external force to the can is rotatably supported at an intermediate portion, and has an arm having a ball formed of an elastic body at one end, and an intermediate portion between the arm supporting portion and the ball. A stopper that stops rotation at a position is provided, a spring that pulls in a direction in which the arm comes into contact with the stopper is mounted, and a driving mechanism that pushes the other end of the arm downward to open is provided. I do.
By using this hitting device, the external force applied to the can is stabilized, and the remaining amount of the contents of the can can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus for detecting the remaining amount of contents of a can according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram of an apparatus for detecting the remaining amount of contents of a can according to Embodiment 2 of the present invention.

FIG. 3 is a configuration diagram of a device for detecting the remaining amount of contents of a can according to Embodiment 3 of the present invention.

FIG. 4 is a configuration diagram of a device for detecting the remaining amount of contents of a can according to Embodiment 4 of the present invention.

FIG. 5 is a configuration diagram of a hitting device of the device for detecting the remaining amount of contents of a can.

FIG. 6 is a configuration diagram of a conventional device for detecting the remaining amount of contents in a can.

[Explanation of symbols]

1 Object (can), 2 hammer, 3 microphone, 4
Amplifier, 5 analog BPF, 6 rectifier, 7 peak hold, 8 corrector, 9 reference value storage means, 10
Comparator, 11 excitation force sensor, 12 amplifier, 13 rectifier, 14 peak hold, 15 ratio calculator, 16
Reference value setting device, 17 trigger detector, 18 display,
19 ratio judgment device, 20 range automatic setting device, 21 range over detector, 31 rectifier, 32 peak hold, 33 range automatic setting device, 34 range over detector, 41 maximum value calculator, 51, 52 A / D converter ,
61 digital BPF, 62 rectifier, 53, 63 maximum value calculator, 64 corrector, 65 reference value storage means, 6
6 comparator, 71 wavelet transformer, 81 short-time FFT calculator, 110 arm, 111 ball, 1
12 rotating shaft, 113 stopper, 114 spring, 11
5 Drive mechanism, 116 mount.

Claims (11)

[Claims] 1. A signal detecting means for detecting a vibration generated from a can to which an external force is applied as a vibration signal; a converting means for converting the vibration signal into a time series signal for each of a plurality of predetermined frequency bands; Extraction means for extracting the maximum value of the sequence signal for each frequency band, and reference value storage means for storing the maximum value pattern and the vibration reference value pattern of the time series signal for each frequency band corresponding to the remaining content. And a comparing means for comparing the pattern of the maximum value of the time-series signal and the pattern of the vibration reference value for each frequency band to detect the remaining amount of contents. 2. The converting means is a plurality of bandpass filters for passing a frequency component of a predetermined frequency band of the vibration signal,
2. The method according to claim 1, wherein the extracting means rectifies the frequency components passing through the band-pass filters, and extracts a maximum value among peak values of the rectified frequency components as maximum values. An apparatus for detecting the remaining amount of contents of a can described in the above. 3. The converting means is a wavelet converting means for performing a wavelet transform on the detection signal, and the extracting means extracts a maximum value of a time-series signal for each frequency band based on a result of the conversion by the wavelet converting means. 2. The device for detecting the remaining amount of contents of a can according to claim 1, wherein: 4. The conversion means is a short-time fast Fourier transform means for performing a short-time fast Fourier transform of the detection signal, and the extraction means is configured to determine a maximum of a time-series signal for each frequency band based on a result of the conversion by the short-time fast Fourier transform means. 2. The apparatus for detecting the remaining amount of contents in a can according to claim 1, wherein the apparatus extracts a value. 5. An external force detecting means for detecting the magnitude of the applied external force, and correcting at least one of a vibration signal, a time-series signal, a maximum value, and a vibration reference value according to the magnitude of the external force. 2. The apparatus according to claim 1, further comprising a correction unit. 6. An external force detecting means for detecting the magnitude of the applied external force, and at least one of a signal detecting means, a converting means, an extracting means, and a comparing means when the magnitude of the external force exceeds a predetermined value. 2. The apparatus according to claim 1, further comprising command means for commanding the start of one operation. 7. An external force detecting means for detecting the magnitude of the applied external force as an external force signal, and a ratio calculating means for calculating a ratio obtained by dividing the external force signal by a preset external force reference value; Based on the vibration signal, the time-series signal, the maximum value, by correcting at least one of the vibration reference value, including a correction means for changing the relationship between the maximum value and the vibration reference value in the comparison means, 2. The apparatus according to claim 1, further comprising a ratio determination unit configured to determine whether the ratio is within a predetermined range. 8. An external force signal amplifying means for amplifying an external force signal and outputting the amplified external force signal, and a vibration signal amplifying means for amplifying the vibration signal and outputting the amplified vibration signal as an amplified vibration signal, wherein the ratio calculating means includes the amplified external force signal. Is used as an external force signal, the converting means uses the amplified external force signal as a vibration signal, and a range for detecting that the peak value of at least one of the amplified external force signal and the amplified vibration signal exceeds a predetermined value. The device for detecting the remaining amount of contents of a can according to claim 7, further comprising an over-detection means. 9. The residual content of a can according to claim 7, further comprising an automatic amplification factor setting device for automatically setting the amplification factor of at least one of the external force signal amplifying device and the vibration signal amplifying device. Quantity detection device. 10. The vibration reference value is set by dividing the remaining content level of the can into a plurality of parts, hitting each of the divided remaining content levels a plurality of times, and vibrating for each frequency band for each of the hits. 2. A content remaining amount according to claim 1, wherein a signal is obtained, and a vibration reference value of a corresponding remaining content level is set between a maximum value and a minimum value of the vibration signal for each of a plurality of frequency bands. Quantity detection device. 11. A striking means for applying an external force to a can is rotatably supported at an intermediate portion, and has an arm to which a ball formed of an elastic body is attached at one end, and a supporting portion of the arm and the ball. A stopper for stopping rotation at an intermediate position of the arm is provided, a spring for pulling the arm in a direction in which the arm comes into contact with the stopper is mounted, and a drive mechanism for pushing down the other end of the arm to open it is provided. The device for detecting the remaining amount of contents in a can according to any one of claims 1 to 10, characterized in that: