JP3855890B2 - Vibration wave determination device - Google Patents

Vibration wave determination device Download PDF

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JP3855890B2
JP3855890B2 JP2002257565A JP2002257565A JP3855890B2 JP 3855890 B2 JP3855890 B2 JP 3855890B2 JP 2002257565 A JP2002257565 A JP 2002257565A JP 2002257565 A JP2002257565 A JP 2002257565A JP 3855890 B2 JP3855890 B2 JP 3855890B2
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vibration wave
color
color information
time
signal
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JP2004093481A (en
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隆史 安面
隆 室崎
隆司 菅沼
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Denso Corp
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Denso Corp
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    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
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Description

【０００１】
【発明の属する技術分野】
本発明は、例えば組付作動など対象物の作動時に生ずる振動波に基いて、対象物の状態、例えば複数個所にある嵌合状態を判定する振動波判定装置に関する。
【０００２】
【従来の技術】
従来、例えば特開平１０−３００７３０号公報の実施形態３には、対象物をハンマーなどで軽くたたき、そのとき発生する音または振動をウエーブレット変換演算手段により周波数分離して、周波数帯域毎の時系列信号を形成し、この時系列信号の判定に基いて、対象物の内容の判別、構造物の割れの検査などを行う技術が記載されている。なお、本明細書では、音と振動を総称して振動波という。
【０００３】
【発明が解決しようとする課題】
上記公報によれば、対象物の特定個所より生ずる振動波に的を絞って判定処理することは可能と思われる。しかしながら、対象物の複数個所より同時もしくは連続して振動波が生じ、それらの振動波が重なるようにして発生する場合には、重なった複数の振動波の個々の作動状態まで判定することは難しい。
【０００４】
本発明は、上記点に鑑みてなされたものであって、対象物の複数箇所より振動波が生じる場合でも、その振動波の同時発生個数を検出して対象物の作動状態を良好に判定することが可能な振動波判定装置を提供することを目的とする。
【０００５】
【課題を解決するための手段】
上記目的を達成するために、請求項１ないし請求項8に記載の技術的手段を採用する。
【０００６】
請求項１記載の発明によれば、対象物の作動時に生ずる振動波を検出入力する振動波入力手段と、入力された振動波を周波数分離して所定の周波数帯域毎の時系列信号を形成するウエーブレット変換演算手段と、時系列信号の信号レベルに基いて、対象物の複数箇所より生ずる所定作動状態を示す目的作動音の同時発生個数を設定すると共に、この同時発生個数に応じた表示色を設定する色変換テーブルと、ウエーブレット変換演算手段にて周波数分離した所定の周波数帯域毎の時系列信号に基いて、色変換テーブルより目的作動音が生じる同時発生個数と該当する表示色を読出し、色情報に変換する色情報変換手段と、色情報を表示する表示手段とを備えたことを特徴とする。
【０００７】
それにより、例えば嵌合等の所定作動状態を示す目的作動音の同時発生個数を、この個数に応じた表示色にて表示でき、対象物の複数箇所の作動状態を容易に判定可能になる。
【０００８】
請求項２記載の発明によれば、ウエーブレット変換演算手段にて周波数分離した時系列信号のノイズ除去もしくは信号レベルの補正を行う信号処理手段を設け、この信号処理手段からの時系列信号を色情報変換手段に与えるようにしたことを特徴とする。それにより、ノイズ等に対し時系列信号の信号レベルを安定させることで、目的作動音の同時発生個数やそれに該当する表示色を精度よく表示、判定することが可能となる。
【０００９】
請求項３記載の発明によれば、色情報変換手段にて変換した色情報に基いて、対象物の状態を判定する判定手段を備えたことで、色情報の表示に加えて、色情報から対象物の状態も判定可能になる。
【００１０】
請求項４記載の発明によれば、判定手段は、色情報に基いて同一表示色となる領域を求め、この領域の大きさから定まる特性値と予め定めた閾値とに基いて、対象物の複数箇所の作動状態を判定することで、一時的な情報で判定せずに、同一表示色の領域、つまり累計的情報で判定するようにし、判定の精度を高めることが可能になる。
【００１１】
請求項５記載の発明によれば、前記特性値とは、目的作動音が同時発生する時間軸上において少なくとも同一表示色となる領域の面積情報を含む値とし、また請求項６記載の発明によれば、前記閾値とは、目的作動音が生じる同時発生個数に応じた値とすることにより、請求項４の効果に加えて、より判定の精度を高めることが可能になる。
【００１２】
請求項７記載の発明によれば、対象物の作動時に生ずる振動波を検出入力する振動波入力手段と、入力された振動波を周波数分離して所定の周波数帯域毎の時系列信号を形成するウエーブレット変換演算手段と、時系列信号の信号レベルに基いて、対象物の複数箇所より生ずる所定作動状態を示す目的作動音の同時発生個数を設定すると共に、この同時発生個数に応じた表示色を設定する色変換テーブルと、ウエーブレット変換演算手段にて周波数分離した所定の周波数帯域毎の時系列信号に基いて、色変換テーブルより目的作動音が生じる同時発生個数と該当する表示色を読出し、色情報に変換する色情報変換手段と、色情報に基いて、対象物の状態を判定する判定手段とを備えたことを特徴とする。
それにより、所定の周波数帯域毎に目的作動音の同時発生個数とそれに該当する表示色を読出し、それらを総合した色情報により対象物の状態を判定できるため、判定の精度を高めることが可能になる。
【００１３】
請求項８記載の発明によれば、判定手段は、色情報に基いて同一表示色となる領域を求め、この領域の大きさから定まる特性値と予め定めた閾値とに基いて、対象物の複数箇所の作動状態を判定することで、一時的な情報で判定せずに、同一表示色の領域、つまり累計的情報で判定するようにし、判定の精度を高めることが可能になる。
【００１４】
【発明の実施の形態】
本発明の一実施形態について図を用いて説明する。
【００１５】
以下の説明では、対象物として製品の組付作業時に発生する組付音（嵌合音）を検出することにより製品の組付（嵌合）不良を判定する例について説明する。しかしながら、本発明の振動波判定装置１００は、この用途に限定されず、その他の用途にも適用可能である。また、音の代わりに振動の検出にも適用できる。
【００１６】
図１は、本発明の一実施形態におけるシステム構成を示す。
【００１７】
ここで、対象物１として本例では樹脂製品の自動組付、特に組付時に大きな音が生じる例として、図２に示すようなスナップフィット機構を用い、図示しない組付設備等により樹脂部品１０１の孔部１０２に樹脂部品１０３の嵌合用突部１０４を嵌合させて両樹脂部品１０１、１０３を組付ける作業工程からの音発生例を挙げている。図３（ａ）、（ｂ）は組付時に発生する振動波の一例であり、（ａ）が組付け良好時、（ｂ）が組付け不良時を示す。図３中の組付け音レベルから分かるように組付良否に応じて嵌合音の音圧レベルが変化する。組付時の音発生の特徴として、組付設備等の動きに伴なう機械作動音と嵌合状況を伝える嵌合音（つまり判定したい目的作動音）とが発生し、両音は部品の組付スピード等の大きさに応じた音圧レベルを有すると共に、両音の音圧レベルは互いに相関して変化することである。
【００１８】
マイクロホン２は、振動波判定の対象物１に発生した振動を音波として検出して電気信号に変換する。マイクロホン２から入力された音圧の電気信号は、振動波判定装置１００の増幅器３に入力されて、A／D変換器４に出力される。このA／D変換器４では音圧信号をデジタル信号に変換して、後段の記憶装置５に出力され記憶処理される。
【００１９】
ウエーブレット変換（Wavelet Transform）演算器６は、所定のタイミングにて記憶装置５に記憶されたデジタル音圧信号Ｓ０を取込み、この音圧信号Ｓ０を、予め設定された周波数帯域毎に分離し、時系列信号Ｓ１に変換する。ここでは連続ウエーブレット変換（Continuous Wavelet Transform）演算器が用いられ、１／２の階乗刻みの周波数帯域毎に時系列信号に変換する離散ウエーブレット変換（Discrete Wavelet Transform）演算器に比べると十分に細分化された周波数帯域毎に分離して、時系列信号Ｓ１を形成している。例えば音圧信号Ｓ０を図５（ａ）とした場合、連続ウエーブレット変換した時系列信号Ｓ１は、図４に示すように、時間ｔ−周波数帯域ｆ−音圧レベルの３次元で表現される。
【００２０】
一般にウエーブレット変換演算器６は、基底関数（ウエーブレット関数）を拡大あるいは縮小することにより、音圧信号Ｓ０を各周波数帯域毎の時系列信号Ｓ１に分離する演算器である。本例では、組付音として１つ以上のスナップフィット機構より発生する目的作動音である嵌合音に合わせた周波数帯域が設定されている。なお、この周波数帯域は、対象とする嵌合音の特性に応じてそれぞれ１つまたは複数の周波数帯域の集合帯域からなる。
【００２１】
信号処理器７は、通常ノイズを除去するためのフィルタ手段から構成され、周波数帯域毎の時系列信号Ｓ１から嵌合音以外の周波数帯域の信号を縮小もしくはカットし、時系列信号Ｓ２として出力する。
【００２２】
なお、信号処理器７として、前述のフィルタ手段の置換もしくはフィルタ手段の後段に補正手段を設け、この補正手段により、図示してないパラメータテーブルから所定の周波数帯域毎に設定された補正量（もしくは補正係数）であるゲインを受けて、周波数帯域毎の時系列信号Ｓ１の重み付けを行い、予め想定した嵌合音以外の周波数帯域の時系列信号Ｓ１はノイズと見なしてレベルを下げ、他方、嵌合音の中でもノイズの少ない周波数帯域を増幅してＳ／N比を向上させるようにし、時系列信号Ｓ２として出力するようにしてもよい。
【００２３】
色変換テーブル８は、入力される時系列信号Ｓ２の信号レベルに基いて、対象物１の複数箇所より生じる嵌合作動状態を示す嵌合音（つまり目的作動音）の同時発生個数（情報）を設定記憶すると共に、この同時発生個数に応じた表示色（情報）を設定記憶している。例えば、音源１個は水色、２個は橙色、３個は茶色とし、またここでは色変換テーブル８は入力される時系列信号Ｓ２の周波数帯域に関係なく共通に設定してある。
【００２４】
色情報変換器９は、信号処理器７からの所定周波数帯域毎の時系列信号Ｓ２の信号レベルに基いて、色変換テーブル８より、所定周波数帯域毎に対象物１において生じる嵌合音の同時発生個数情報とこの同時発生個数に応じた表示色情報とを読出し、順次記憶手段９ａに記憶して各情報を総合し色情報に変換する。
【００２５】
色情報変換器９は、所定周波数帯域毎に読出した表示色情報を総合し、例えば図５（ｂ）に示すような時間軸ｔと周波数帯域の２次元表示画面において、領域により表示色が異なるような形式にて表示器１２に表示させる。なお、図５（ａ）はマイクロホン２に入力される元信号となる記憶装置５のデジタル音圧信号Ｓ０を示し、図５（ｂ）はこの音圧信号Ｓ０を所定周波数帯域毎の時系列信号Ｓ２に分離して濃淡により嵌合音の同時発生個数を色別表示した例である。
【００２６】
判定器１０は、色情報変換器９で求めた色情報およびテーブル１１にある予め定めた閾値に基いて、対象物１の複数箇所の嵌合作動状態を判定する。
【００２７】
ここで、判定器１０において複数箇所の嵌合音が重なる嵌合作動状態の判定要領について説明する。
【００２８】
まず前提として、マイクロホン２が捕らえる振動波（音圧信号）には予め想定された嵌合音の他に、組付設備等の動きに伴なう機械作動音や設備周囲音が含まれる。そこで、予め想定された嵌合音以外の音をカットもしくは縮小した振動波（音圧信号）とすれば、重なった嵌合音の個数に応じて音圧レベルは変化するので、本発明ではそれを利用する。
【００２９】
色情報変換器９は、所定周波数帯域毎の時系列信号Ｓ２の信号レベルに基いて、各時点での嵌合音の同時発生個数情報とそれに応じた表示色情報を読出し、それらの情報を総合して色情報として表示器１２に出力している。そこで表示器１２には色情報が色別表示されるため、目視で嵌合音の同時発生個数を概略判定（検査）可能である。
【００３０】
他方、判定器１０において嵌合作動状態を正確に判定するためには、各時点での嵌合音の同時発生個数等の一時的な色情報から直接判定せずに、色情報の累計的情報として嵌合音の個数別同時発生状況（もしくは同一表示色情報の分布状況）を時間軸と周波数帯域による2次元の領域で捕らえ、その領域の大きさ（面積値等）、形状（縦長、横長等）、もしくは出現時間間隔等を特性値として求め、その特性値を予め定めた閾値と比較することにより、嵌合音の同時発生個数状況を安定的かつ精度よく判定し、それにより対象物１の複数箇所の嵌合作動が全て良好になされたかを判定するようにしている。なお、特性値の演算、決定や判定処理には既知の画像処理技術を用いて実現可能である。
【００３１】
判定器１０は、全ての嵌合が適切になされた場合には正常（合格）と判定し、嵌合されないものがある場合には異常（不合格）と判定し、表示器１３に判定結果を表示させる。また異常（不合格）の場合には警報器１４に出力し警報を発生させる。
【００３２】
次に、上記構成からなる振動波判定装置１００の判定フローをまとめると、図６のとおりである。図７は振動波の信号波形図である。
【００３３】
装置１００に判定開始が指示されると、対象物１から発生する振動波を、マイクロホン２〜記憶装置５によりデジタル音圧信号Ｓ０（図５（ａ））として録音（ステップ２０１）する。ウエーブレット変換演算器６では、このデジタル音圧信号Ｓ０を目的作動音である嵌合音に合わせた周波数帯域（図４）をもつ時系列信号Ｓ１に分離、抽出（ステップ２０２）する。次に信号処理器７で、フィルタ手段によりこれらの時系列信号Ｓ１から嵌合音以外の周波数帯域を縮小もしくはカットする。もしくは補正手段により、ゲインG（補正量もしくは補正係数）により時系列信号S１を補正してS／N比を向上（ステップ２０３）させる。
【００３４】
次に色情報変換器９で、信号処理器７からの所定周波数帯域毎の時系列信号Ｓ２のレベルに基いて、色変換テーブル８より嵌合音が生じる同時発生個数と該当する表示色を読出し、色情報に変換すると共に、表示器１２に色情報を表示（ステップ２０４）させる。
【００３５】
次に判定器１０で、色情報に基いて同一表示色となる領域を求め、この領域の大きさから定まる特性値と予め定めた閾値とに基いて、対象物１の複数箇所の嵌合作動状態を判定し、製品の組付（嵌合）良否を判定（ステップ２０５）する。閾値以上であれば合格表示（全数嵌合良好）、閾値より小であれば不合格表示（嵌合不良あり）かつ警報出力を行う（ステップ２０６、２０７）ことになる。
【図面の簡単な説明】
【図１】本発明の一実施形態のシステム構成を示す構成図である。
【図２】図１の製品の組付工程の一部を示す図である。
【図３】図２の工程において検出される音圧波形を示す図である。
【図４】音圧信号を連続ウエーブレット変換した所定の周波数帯域毎の時系列信号を示す図である。
【図５】（ａ）はマイクロホン２で検出した音圧信号の波形図、（ｂ）はこの音圧信号を周波数分離した所定の周波数帯域毎の時系列信号を、色情報変換器９で変換した色情報を示す図である。
【図６】図１に示す振動波判定装置１００の処理フローを示すフローチャートである。
【符号の説明】
１ 対象物
２ マイクロホン(振動波入力手段)
５ 記憶装置
６ ウエーブレット変換演算器
７ 信号処理器(信号処理手段)
８ 色変換テーブル
９ 色情報変換器（色情報変換手段）
１０ 判定器（判定手段）
１１ テーブル
１２、１３ 表示器
１４ 警報器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration wave determination device that determines a state of an object, for example, a fitting state at a plurality of places, based on vibration waves generated during the operation of the object such as an assembly operation.
[0002]
[Prior art]
Conventionally, for example, in Embodiment 3 of Japanese Patent Laid-Open No. 10-300730, a target is tapped with a hammer or the like, and the sound or vibration generated at that time is frequency-separated by a wavelet transform computing means, and the time for each frequency band is determined. A technique is described in which a series signal is formed, and based on the determination of the time series signal, the contents of the object are discriminated and the structure is inspected for cracks. In this specification, sound and vibration are collectively referred to as vibration waves.
[0003]
[Problems to be solved by the invention]
According to the above publication, it seems possible to perform the determination process focusing on the vibration wave generated from a specific part of the object. However, when vibration waves are generated simultaneously or continuously from a plurality of locations of an object and the vibration waves are generated so as to overlap, it is difficult to determine the individual operating states of the plurality of overlapped vibration waves. .
[0004]
The present invention has been made in view of the above points, and even when vibration waves are generated from a plurality of locations on an object, the number of simultaneously generated vibration waves is detected and the operating state of the object is determined satisfactorily. An object of the present invention is to provide a vibration wave determination device capable of performing the above-described operation.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the technical means according to claims 1 to 8 are employed.
[0006]
According to the first aspect of the present invention, the vibration wave input means for detecting and inputting the vibration wave generated when the object is operated, and the input vibration wave are frequency-separated to form a time-series signal for each predetermined frequency band. Based on the wavelet conversion calculation means and the signal level of the time-series signal, the number of simultaneously generated target operating sounds indicating predetermined operating states generated from a plurality of locations of the object is set, and the display color corresponding to the number of simultaneously generated signals Based on the color conversion table that sets the frequency and the time-series signal for each predetermined frequency band that is frequency-separated by the wavelet conversion calculation means, the number of simultaneously generated target operating sounds and the corresponding display color are read from the color conversion table The color information conversion means for converting to color information and the display means for displaying the color information are provided.
[0007]
Thereby, for example, the number of simultaneously generated target operation sounds indicating a predetermined operation state such as fitting can be displayed in a display color corresponding to this number, and the operation states of a plurality of locations of the object can be easily determined.
[0008]
According to the second aspect of the present invention, the signal processing means for removing noise or correcting the signal level of the time series signal frequency-separated by the wavelet transform calculation means is provided, and the time series signal from the signal processing means is color-coded. It is characterized by being provided to the information conversion means. Thereby, by stabilizing the signal level of the time-series signal against noise or the like, it is possible to accurately display and determine the simultaneous occurrence number of the target operation sound and the display color corresponding thereto.
[0009]
According to the invention described in claim 3, by providing the determination means for determining the state of the object based on the color information converted by the color information conversion means, in addition to the display of the color information, The state of the object can also be determined.
[0010]
According to the fourth aspect of the present invention, the determination means obtains an area having the same display color based on the color information, and based on the characteristic value determined from the size of the area and a predetermined threshold, By determining the operation states at a plurality of locations, it is possible to improve the accuracy of the determination by determining with the region of the same display color, that is, cumulative information, without determining with temporary information.
[0011]
According to the invention described in claim 5, the characteristic value is a value including area information of at least the region having the same display color on the time axis where the target operation sound is generated simultaneously. Therefore, by setting the threshold value to a value corresponding to the number of simultaneous occurrences where the target operation sound is generated, in addition to the effect of the fourth aspect, it is possible to further increase the accuracy of the determination.
[0012]
According to the seventh aspect of the present invention, the vibration wave input means for detecting and inputting the vibration wave generated when the object is operated, and the input vibration wave are frequency-separated to form a time-series signal for each predetermined frequency band. Based on the wavelet conversion calculation means and the signal level of the time-series signal, the number of simultaneously generated target operating sounds indicating predetermined operating states generated from a plurality of locations of the object is set, and the display color corresponding to the number of simultaneously generated signals Based on the color conversion table that sets the frequency and the time-series signal for each predetermined frequency band that is frequency-separated by the wavelet conversion calculation means, the number of simultaneously generated target operating sounds and the corresponding display color are read from the color conversion table The color information conversion means for converting into color information and the determination means for determining the state of the object based on the color information are provided.
This makes it possible to read the number of simultaneous occurrences of target operating sounds and their corresponding display colors for each predetermined frequency band, and to determine the state of the object based on the color information that combines them. Become.
[0013]
According to the eighth aspect of the present invention, the determination means obtains an area having the same display color based on the color information, and based on the characteristic value determined from the size of the area and a predetermined threshold value, By determining the operation states at a plurality of locations, it is possible to improve the accuracy of the determination by determining with the region of the same display color, that is, cumulative information, without determining with temporary information.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0015]
In the following description, an example will be described in which a product assembly (fitting) failure is determined by detecting an assembly sound (fitting sound) generated during assembly of the product as an object. However, the vibration wave determination apparatus 100 of the present invention is not limited to this application, and can be applied to other applications. It can also be applied to detection of vibration instead of sound.
[0016]
FIG. 1 shows a system configuration in an embodiment of the present invention.
[0017]
Here, as an object 1, in this example, as an example of automatic assembly of a resin product, particularly a case where a loud noise is generated at the time of assembly, a snap fit mechanism as shown in FIG. An example of sound generation from a work process in which the fitting protrusion 104 of the resin component 103 is fitted in the hole portion 102 and the both resin components 101 and 103 are assembled is given. FIGS. 3A and 3B are examples of vibration waves generated at the time of assembly. FIG. 3A shows a case where assembly is good, and FIG. 3B shows a case where assembly is poor. As can be seen from the assembled sound level in FIG. 3, the sound pressure level of the fitting sound changes depending on whether the assembly is good or bad. As a feature of sound generation at the time of assembly, a mechanical operation sound accompanying the movement of the assembly equipment and a fitting sound that conveys the fitting status (that is, a target operation sound to be judged) are generated. It has a sound pressure level corresponding to the magnitude of the assembly speed and the like, and the sound pressure levels of both sounds change in correlation with each other.
[0018]
The microphone 2 detects the vibration generated in the object 1 for vibration wave determination as a sound wave and converts it into an electric signal. The sound pressure electrical signal input from the microphone 2 is input to the amplifier 3 of the vibration wave determination device 100 and output to the A / D converter 4. The A / D converter 4 converts the sound pressure signal into a digital signal, which is output to the storage device 5 at the subsequent stage for storage processing.
[0019]
The wavelet transform computing unit 6 takes in the digital sound pressure signal S0 stored in the storage device 5 at a predetermined timing, and separates this sound pressure signal S0 into preset frequency bands, The time series signal S1 is converted. In this case, a continuous wavelet transform operator is used, which is sufficient compared to a discrete wavelet transform operator that converts a time-series signal into each frequency band of 1/2 factorial steps. The time series signal S1 is formed by dividing the frequency band into subdivided frequency bands. For example, when the sound pressure signal S0 is shown in FIG. 5A, the time series signal S1 subjected to continuous wavelet transform is expressed in three dimensions of time t-frequency band f-sound pressure level as shown in FIG. .
[0020]
In general, the wavelet transform computing unit 6 is a computing unit that separates the sound pressure signal S0 into time-series signals S1 for each frequency band by enlarging or reducing the basis function (wavelet function). In this example, a frequency band is set as an assembly sound in accordance with a fitting sound that is a target operation sound generated from one or more snap-fit mechanisms. This frequency band is composed of a set band of one or a plurality of frequency bands, depending on the characteristics of the target fitting sound.
[0021]
The signal processor 7 is composed of filter means for removing normal noise. The signal processor 7 reduces or cuts a signal in a frequency band other than the fitting sound from the time-series signal S1 for each frequency band, and outputs it as a time-series signal S2. .
[0022]
As the signal processor 7, a correction means is provided at the subsequent stage of the above-mentioned filter means or after the filter means, and the correction amount (or the correction amount set for each predetermined frequency band from the parameter table (not shown) (or by this correction means) The time series signal S1 for each frequency band is weighted in response to a gain that is a correction coefficient), and the time series signal S1 in a frequency band other than the presumed fitting sound is regarded as noise and the level is lowered. A frequency band with less noise in the combined sound may be amplified to improve the S / N ratio and output as the time-series signal S2.
[0023]
The color conversion table 8 is the number (information) of simultaneously generated fitting sounds (that is, target operation sounds) indicating fitting operation states generated from a plurality of locations of the object 1 based on the signal level of the input time-series signal S2. Is set and stored, and display color (information) corresponding to the number of simultaneous occurrences is set and stored. For example, one sound source is light blue, two are orange, and three are brown. Here, the color conversion table 8 is set in common regardless of the frequency band of the input time-series signal S2.
[0024]
Based on the signal level of the time-series signal S2 for each predetermined frequency band from the signal processor 7, the color information converter 9 uses the color conversion table 8 to simultaneously generate fitting sounds generated in the object 1 for each predetermined frequency band. The generated number information and the display color information corresponding to the simultaneously generated number are read out and sequentially stored in the storage means 9a, and each information is integrated and converted into color information.
[0025]
The color information converter 9 combines the display color information read for each predetermined frequency band, and the display color varies depending on the area on the two-dimensional display screen of the time axis t and frequency band as shown in FIG. 5B, for example. It is displayed on the display 12 in such a format. 5A shows the digital sound pressure signal S0 of the storage device 5 as an original signal input to the microphone 2, and FIG. 5B shows the sound pressure signal S0 as a time-series signal for each predetermined frequency band. This is an example in which the number of simultaneously generated fitting sounds is displayed for each color according to light and shade after being separated into S2.
[0026]
The determiner 10 determines a fitting operation state at a plurality of locations of the target 1 based on the color information obtained by the color information converter 9 and a predetermined threshold value in the table 11.
[0027]
Here, the determination point of the fitting operation state in which the fitting sounds at a plurality of places overlap in the determiner 10 will be described.
[0028]
First, as a premise, the vibration wave (sound pressure signal) captured by the microphone 2 includes, in addition to the fitting sound assumed in advance, machine operating sound and equipment ambient sound accompanying the movement of the installed equipment and the like. Therefore, if a vibration wave (sound pressure signal) obtained by cutting or reducing a sound other than a fitting sound assumed in advance is used, the sound pressure level changes according to the number of overlapping fitting sounds. Is used.
[0029]
Based on the signal level of the time-series signal S2 for each predetermined frequency band, the color information converter 9 reads information on the number of simultaneous mating sounds generated at each time point and display color information corresponding to the information, and integrates the information. Then, it is output to the display unit 12 as color information. Accordingly, since the color information is displayed by color on the display device 12, the number of simultaneous occurrences of the fitting noise can be roughly determined (inspected) visually.
[0030]
On the other hand, in order to accurately determine the fitting operation state in the determiner 10, the cumulative information of the color information is not directly determined from the temporary color information such as the number of simultaneously generated fitting sounds at each time point. Assuming that the number of mating sounds generated simultaneously (or the distribution status of the same display color information) is captured in a two-dimensional area based on the time axis and frequency band, the size (area value, etc.) and shape (vertical and horizontal) of that area Etc.) or an appearance time interval or the like as a characteristic value, and the characteristic value is compared with a predetermined threshold value, so that the simultaneous occurrence number of fitting sounds can be determined stably and accurately. It is determined whether or not the fitting operations at a plurality of locations are all performed satisfactorily. Note that the characteristic value calculation, determination, and determination processing can be realized by using a known image processing technique.
[0031]
The determination device 10 determines that the fitting is properly performed (normal) (accepted), and if there is anything that is not fitted, the determination device 10 determines the abnormality (failed). Display. In the case of an abnormality (failure), the alarm is output to the alarm device 14 to generate an alarm.
[0032]
Next, the determination flow of the vibration wave determination apparatus 100 configured as described above is summarized as shown in FIG. FIG. 7 is a signal waveform diagram of a vibration wave.
[0033]
When the apparatus 100 is instructed to start the determination, the vibration wave generated from the object 1 is recorded as a digital sound pressure signal S0 (FIG. 5A) by the microphone 2 to the storage device 5 (step 201). The wavelet transform computing unit 6 separates and extracts the digital sound pressure signal S0 into a time-series signal S1 having a frequency band (FIG. 4) that matches the fitting sound that is the target operation sound (step 202). Next, in the signal processor 7, the frequency band other than the fitting sound is reduced or cut from these time series signals S1 by the filter means. Alternatively, the correction means corrects the time series signal S1 with the gain G (correction amount or correction coefficient) to improve the S / N ratio (step 203).
[0034]
Next, the color information converter 9 reads the number of simultaneously generated fitting sounds and the corresponding display color from the color conversion table 8 based on the level of the time-series signal S2 for each predetermined frequency band from the signal processor 7. The color information is converted into color information, and the color information is displayed on the display 12 (step 204).
[0035]
Next, the determination unit 10 obtains a region having the same display color based on the color information, and the fitting operation at a plurality of locations of the object 1 is performed based on a characteristic value determined from the size of the region and a predetermined threshold value. The state is determined, and whether or not the product is assembled (fitted) is determined (step 205). If it is equal to or greater than the threshold value, a pass display (all fittings are good), and if it is smaller than the threshold value, a fail display (with poor fitting) and alarm output are performed (steps 206 and 207).
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a system configuration of an embodiment of the present invention.
FIG. 2 is a diagram showing a part of the assembly process of the product of FIG. 1;
FIG. 3 is a diagram showing a sound pressure waveform detected in the process of FIG. 2;
FIG. 4 is a diagram illustrating a time-series signal for each predetermined frequency band obtained by continuously wavelet transforming a sound pressure signal.
5A is a waveform diagram of a sound pressure signal detected by the microphone 2. FIG. 5B is a color information converter 9 that converts a time-series signal for each predetermined frequency band obtained by frequency-separating the sound pressure signal. It is a figure which shows the performed color information.
6 is a flowchart showing a processing flow of the vibration wave determination apparatus 100 shown in FIG. 1;
[Explanation of symbols]
1 Object 2 Microphone (vibration wave input means)
5 storage device 6 wavelet transform computing unit 7 signal processor (signal processing means)
8 color conversion table 9 color information converter (color information conversion means)
10 Determinator (determination means)
11 Table 12, 13 Display 14 Alarm

Claims (8)

対象物の作動時に生ずる振動波を検出入力する振動波入力手段と、
入力された前記振動波を周波数分離して所定の周波数帯域毎の時系列信号を形成するウエーブレット変換演算手段と、
時系列信号の信号レベルに基いて、前記対象物の複数箇所より生ずる所定作動状態を示す目的作動音の同時発生個数を設定すると共に、この同時発生個数に応じた表示色を設定する色変換テーブルと、
前記ウエーブレット変換演算手段にて周波数分離した前記所定の周波数帯域毎の時系列信号に基いて、前記色変換テーブルより前記目的作動音が生じる同時発生個数と該当する表示色を読出し、色情報に変換する色情報変換手段と、
前記色情報を表示する表示手段とを備えたことを特徴とする振動波判定装置。Vibration wave input means for detecting and inputting vibration waves generated during operation of the object;
Wavelet transform computing means for frequency-separating the input vibration wave to form a time-series signal for each predetermined frequency band;
Based on the signal level of the time-series signal, a color conversion table for setting the number of simultaneously generated target operating sounds indicating a predetermined operating state generated from a plurality of locations of the object and setting a display color according to the number of simultaneously generated signals When,
Based on the time-series signal for each of the predetermined frequency bands frequency-separated by the wavelet conversion calculation means, the number of simultaneous occurrences of the target operation sound and the corresponding display color are read from the color conversion table, and color information is obtained. Color information conversion means for conversion;
A vibration wave determination apparatus comprising: display means for displaying the color information. 前記ウエーブレット変換演算手段にて周波数分離した前記時系列信号のノイズ除去もしくは信号レベルの補正を行う信号処理手段を設け、この信号処理手段からの時系列信号を前記色情報変換手段に与えるようにしたことを特徴とする請求項１に記載の振動波判定装置。Signal processing means for performing noise removal or signal level correction of the time series signal frequency-separated by the wavelet transformation calculation means is provided, and the time series signal from the signal processing means is provided to the color information conversion means. The vibration wave determination device according to claim 1, wherein: 前記色情報変換手段にて変換した前記色情報に基いて、前記対象物の状態を判定する判定手段を備えたことを特徴とする請求項１に記載の振動波判定装置。The vibration wave determination apparatus according to claim 1, further comprising a determination unit that determines a state of the object based on the color information converted by the color information conversion unit. 前記判定手段は、前記色情報に基いて同一表示色となる領域を求め、この領域の大きさから定まる特性値と予め定めた閾値とに基いて、前記対象物の複数箇所の作動状態を判定することを特徴とする請求項３に記載の振動波判定装置。The determination means determines an area having the same display color based on the color information, and determines an operation state at a plurality of locations of the object based on a characteristic value determined from the size of the area and a predetermined threshold value. The vibration wave determination device according to claim 3, wherein: 前記特性値とは、前記目的作動音が同時発生する時間軸上において少なくとも同一表示色となる領域の面積情報を含む値であることを特徴とする請求項４に記載の振動波判定装置。5. The vibration wave determination device according to claim 4, wherein the characteristic value is a value including area information of a region having at least the same display color on a time axis where the target operation sound is simultaneously generated. 前記閾値とは、前記目的作動音が生じる同時発生個数に応じた値であることを特徴とする請求項４に記載の振動波判定装置。5. The vibration wave determination device according to claim 4, wherein the threshold value is a value corresponding to the number of simultaneous occurrences of the target operation sound. 対象物の作動時に生ずる振動波を検出入力する振動波入力手段と、
入力された前記振動波を周波数分離して所定の周波数帯域毎の時系列信号を形成するウエーブレット変換演算手段と、
時系列信号の信号レベルに基いて、前記対象物の複数箇所より生ずる所定作動状態を示す目的作動音の同時発生個数を設定すると共に、この同時発生個数に応じた表示色を設定する色変換テーブルと、
前記ウエーブレット変換演算手段にて周波数分離した前記所定の周波数帯域毎の時系列信号に基いて、前記色変換テーブルより前記目的作動音が生じる同時発生個数と該当する表示色を読出し、色情報に変換する色情報変換手段と、
前記色情報に基いて、前記対象物の状態を判定する判定手段とを備えたことを特徴とする振動波判定装置。Vibration wave input means for detecting and inputting vibration waves generated during operation of the object;
Wavelet transform computing means for frequency-separating the input vibration wave to form a time-series signal for each predetermined frequency band;
Based on the signal level of the time-series signal, a color conversion table for setting the number of simultaneously generated target operating sounds indicating a predetermined operating state generated from a plurality of locations of the object and setting a display color according to the number of simultaneously generated signals When,
Based on the time-series signal for each of the predetermined frequency bands frequency-separated by the wavelet conversion calculation means, the number of simultaneous occurrences of the target operation sound and the corresponding display color are read from the color conversion table, and color information is obtained. Color information conversion means for conversion;
A vibration wave determination apparatus comprising: determination means for determining the state of the object based on the color information. 前記判定手段は、前記色情報に基いて同一表示色となる領域を求め、この領域の大きさから定まる特性値と予め定めた閾値とに基いて、前記対象物の複数箇所の作動状態を判定することを特徴とする請求項７に記載の振動波判定装置。The determination means determines an area having the same display color based on the color information, and determines an operation state at a plurality of locations of the object based on a characteristic value determined from the size of the area and a predetermined threshold value. The vibration wave determination apparatus according to claim 7, wherein:
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