JP3885253B2 - Elliptical vibration device - Google Patents

Description

【００２１】
（１）式において、ｓは複素周波数ｊωを表すが、ｓにｊωを代入すると、（２）式が得られる。
【００２２】
【数２】

【００２３】
（２）式から実角周波数に対する入力ｒと振巾出力ｘの比｜ｘ（ｊω）／ｒ（ｊω）｜は（３）式のようになる。
【００２４】
【数３】

【００２５】
（３）式にｍ＝１、ｃ＝０．０１、Ｋ＝１、Ｋ₀ ＝１を代入すると、（４）式となる。
【００２６】
【数４】

【００２７】
（４）式をプロットすると、図３に示すようなグラフが得られる。次に、本発明に係る速度フィードバックコントローラ３２ａを使用した場合には（５）式が得られる。
【００２８】
【数５】

【００２９】
ｓにｊωを代入すると（６）式が得られる。
【００３０】
【数６】

【００３１】
（６）式から実角周波数ωに対する入力と出力の振巾比｜ｘ（ｊω）／ｒ（ｊω）｜は（７）式のように表せる。
【００３２】
【数７】

【００３３】
（７）式にｍ＝１、ｃ＝０．０１、Ｋ＝１、Ｋ₀ ＝１、Ｋ₁ ＝２０、Ｋ₂ ＝０．１９／２０を代入すると（８）式が得られる。
【００３４】
【数８】

【００３５】
（８）式を角周波数ωに関してプロットすると図４のグラフが得られる。
【００３６】
以上のように、従来の速度フィードバックコントローラ３２ａを用いない場合と、本発明のように速度フィードバックコントローラ３２ａを用いた場合とではωと振巾比との関係は図３及び図４のように大きく異なるものである。つまり、従来においては、ω＝１、すなわち共振状態においては振巾比は１００に対してωが充分に小さく、すなわち共振点から大きく離れている場合には１となる。すなわち共振倍率は１００倍であるのに対して、本発明においては図４で示すようにω＝１では従来と同様に振巾比は１００であるが、角周波数ωが１より充分に小さい場合、すなわち共振点から遠く離れた場合には２０となる。従って共振倍率は５である。然しながら角周波数ωが１の近傍では、図３と図４と比較して分かるように、従来では僅かにωが変化するだけで大きく変動しているのに対し、本願発明では僅かしか変動しない。すなわち第１の機械振動系３５ａが使用開始時から何らかの経時変化、例えば振動パーツフィーダである場合にはワークを含むボウルの全質量やボウルとベースブロックとを結合する板ばねの全ばね常数の変化により固有振動数が僅かでも変化すると大きく変動するに対し、本願発明では僅かしか変動しない。
【００３７】
なお、以上の実施の形態において、増巾部４３のゲインＫ₁ 及び速度フィードバックゲインＫ₂ は以下のようにして定められる。すなわち、固有振動数付近での振巾比ｘ／ｒの変化、位相の変化をゆるやかにしたい場合には振動系の減衰係数を大きくすればよいのだが、本実施の形態では、非制御の減衰係数ｃ＝０．０１としている。これに対し、制御によって系の減衰係数ｃ_S ＝０．２としている。すなわち、可動部Ｍに対する制御による減衰係数ｃ_S ＝０．２としたいので速度フィードバックゲインｃ’＝ｃ_S −ｃ＝０．２−０．０１＝０．１９とすればよい。すなわち図２において、ｃ’＝Ｋ₁ ×Ｋ₂ ×Ｋ₀ （Ｋ₀ ＝１ではｃ’＝Ｋ₁ ×Ｋ₂ ）。また共振倍率＝１／２ζ_s ＝１／ｃ_s ／（ｍＫの平方根）＝１／０．２＝５（ここでｍ＝１、Ｋ＝１）。
【００３８】
固有振動数において、振巾１の入力に対し非制御時と同じ振巾１００の出力を得るには入力に２０倍のゲインをかける必要がある。よって増巾部４３のゲインＫ₁ ＝２０と設定する。この時、Ｋ₂ はｃ’＝Ｋ₂ ×Ｋ₁ より０．１９＝Ｋ₂ ×２０。よって、Ｋ₂ ＝０．１９／２０となる。これが上記のゲインＫ₁ ＝２０、Ｋ₂ ＝０．１９／２０である。
【００３９】
本発明の実施の形態は以上のように構成され作用するのであるが、次に他の実施の形態について説明する。
【００４０】
図７はその楕円振動装置の全体５０を示すが、上記実施の形態に対応する部分については同一の符号を付し、その詳細な説明は省略する。すなわち本実施の形態によれば第１振動駆動子５１には電磁石が用いられる。電磁石は公知のように、鉄心にコイルを巻装させ、これに交流を通電することにより空隙をおいて対向している可動コアとの間に交番磁気吸引力を発生し機械振動系の可動部を振動させるものであるが、このようなアクチュエータにおいては、（１／Ｒ）×（１／１＋Ｔｓ）なる遅れ要素がある。このために振動系から振動速度をフィードバックしても振動系に制御力として加わる場合には、この遅れ分を補償しなければ上述のような作用を行なうことができない。（以上では遅れ要素を無視するか、遅れ要素のない振動駆動子を用いるものとしている。）従って、本実施の形態においてはアクチュエータである電磁石５１の電流成分ｉを電流検出し、これを電圧に変換して第３の比較部５２に負帰還させている。すなわち、本実施の形態におけるコントローラ５３ａは電流検出ゲインＫｉ及び電流フィードバックゲインＫ₄ を備えており、この電流フィードバックゲインＫ₄ の出力、すなわち電圧値として第３の比較部５２に負帰還される。アクチュエータ５１への入力ｅと出力ｉの間には（１／Ｒ）×（１／１＋Ｔｓ）なる遅れ要素があるが、このマイナーループによるフィードバックにより、いわば過励磁として電力増巾器３３ａの出力ｅがアクチュエータ５１を通ることによる遅れを補償するようにしている。これによって上述のような作用、効果を確実に得ることができる。
【００４１】
従来の速度フィードバックコントローラがない場合の位相特性は（９）式によって示される。
【００４２】
【数９】

【００４３】
（９）式において、ｍ＝１、ｃ＝０．０１、Ｋ＝１とおくと（１０）式が得られる。
【００４４】
【数１０】

【００４５】
また、本発明の速度フィードバックコントローラを用いた場合には（１１）式によってその位相特性が表される。
【００４６】
【数１１】

【００４７】
同様にｍ＝１、ｃ＝０．０１、Ｋ＝１、Ｋ₀ ＝１、Ｋ₁ ＝２０、Ｋ₂ ＝０．１９／２０を代入すると（１２）式が得られる。
【００４８】
【数１２】

【００４９】
（１０）式、（１２）式に関し、それぞれ横軸に角周波数ωをとってプロットしたものが図５及び図６によって示されるが、図５から明らかな様に、従来では角周波数ωが１、すなわち共振点では位相差角Ｇは−９０度であるが、これが僅かでも変化すると０度から１８０度の間で急激に変化する。従って従来では、最初、水平振動系及び垂直振動系がそれぞれ固有周波数で駆動されていて力と変位との位相差が−９０度であっても質量又はばね常数に経時変化があれば、図５に示すように位相差は急激に−９０度から変化する。これにより最初は水平方向の振動と垂直方向の振動との間に位相調節器４０により調節された６０度で最適の楕円振動をしていたとしても、この様な変化により、この６０度を保つことができず振巾も大きく変動して楕円振動の形状が異なるものとなり、最適楕円振動から程遠いものとなる。
【００５０】
図６は、本発明に関し角周波数ωに対して位相差をプロットしたものであるが、図から明らかなように共振周波数、すなわちω＝１においては位相差は−９０度であるが、質量及びばね常数が何らかの理由で経時変化をしたとしても、従来と比べるとその変化率は小さく、従って位相調節器４０により最適位相差を保つべく調節されていれば、これを再調整することなく水平振動と垂直振動との間の位相差を６０度近くとすることにより最適な楕円振動を得ることができる。
【００５１】
次に、従来と本発明とで固有振動数が変化した時にどの様な楕円振動の形状変化があるかを図８及び図９に示す。図８は従来技術を示すものであるが、水平成分の固有振動数ωｎｘが１．００である場合には、図８においてＡ、Ｂ、Ｃで示す様に垂直方向の固有振動数ωｎｙが、０．９９、１．００、１．０１と変化すると共に長軸の方向も変わり水平方向に対して逆方向、またωｎｙ＝１．０１ではωｎｙ＝１．００と同じ方向である。水平方向の大きさは同一であるが、垂直方向の大きさはωｎｙ＝１．００で最大である。また、ωｎｘが１％増減した場合、すなわち０．９９及び１．０１ではωｎｙが０．９９、１．００、１．０１と変化するにつれて図示するような楕円形状を示すが、ωｎｘ＝０．９９においては、やはり図Ａ、Ｂ、Ｃにおいて示すようにωｎｙ＝１．００では垂直方向の大きさが最大であるが、水平方向の大きさは他と余り変わらない。またωｎｙ＝０．９９及び１．０１ではほゞ同一の楕円形状を呈している。またωｎｘ＝１．０１ではωｎｙ＝１．００で垂直方向の大きさは最大であり、水平方向の大きさは余り変わらない。しかし、何れにしても楕円の形状は大きく異なる。図９は本発明の実施の形態でのωｎｘが０．９９、１．００及び１．０１、ωｎｙが０．９９、１．００及び１．０１と変化した場合に図Ａ、Ｂ、Ｃに示すように変化するのであるが、図から明らかなようにその楕円形状は殆ど変化しない。従って上述したように、本発明においては固有振動数が経時変化したとしても常に最適な楕円振動を行なうことは明らかである。また水平方向と垂直方向の振動の位相差は従来では６０度に最初に設定しても、固有振動数が±１％増減すると±６０度も変動するのに対し、本発明においては±６度程度である。よって位相差角を常に６０度又はこの近辺に保持することができ、常に最適の楕円振動を得ることが出来るのは明らかである。
【００５２】
従来技術において、水平方向の固有振動数ωｎｘが変化した場合には、水平方向の振巾が大きく変わる。ωｎｘ＝１．００、ωｎｙ＝１．００の場合には水平、垂直振巾共に１００となっているが、ωｎｙ＝１．００でωｎｘ＝０．９９、あるいはωｎｘ＝１．０１の場合には、Ｂ図で示すように垂直振巾は１００のままであるが、水平振巾はそれぞれ４５程度となっていることが分かる。同様のことがωｎｙ＝０．９９及び１．０１では、図８のＡ図及びＣ図で明らかである。何れにしてもωｎｘ、ωｎｙが共に１．００から変化した場合には水平、垂直振巾共に大きく変化していることがわかる。然るに本願発明では、図９から明らかなようにωｎｘ、ωｎｙが１．００から０．９９又は１．０１に変化したとしても垂直方向及び水平方向の振巾は殆ど変化しない。
【００５３】
なお力と変位の位相差については（１０）式及び（１２）式から明らかなように、またこれをプロットした図５及び図６から明らかな様に、垂直方向においても水平方向においても固有振動数が±１％の増減では本発明では殆ど９０度から変化せず、上述したように水平方向と垂直方向との間の振動の位相差は６０度±６度とすることができる。よって最適な楕円振動を得ることができる。他方、従来では９０度から大きく変化して垂直と水平とで振動の位相差は６０度±約６０度であり、最適楕円振動を得ることができない。
【００５４】
なお、以上においては、第１機械振動系３５ａ、すなわち水平振動系について説明したが、勿論垂直振動系においても同様のことが言え、従って位相特性やゲイン特性を表すグラフは水平方向にも垂直方向にも共通である。
【００５５】
なお、図８で示す従来の速度フィードバックを使用しない楕円振動では、ωｎｘ及びωｎｙが固有振動周波数より±１％増減すると、その形状及び垂直方向、水平方向の振巾も大きく変動するのであるが、更に、その楕円の回転方向、すなわち時計方向にループが回転するか反時計方向にループが回転するか、という違いもでてくる。場合によってはこれによって、トラック上の部品の移送方向を逆方向にする場合もあり、もちろん最適な楕円振動における搬送速度よりは大幅に小となる。これに対して図９で示す本願の速度フィードバックをかける場合には、ωｎｘ及びωｎｙが固有周波数の１から±１％増減して、それぞれ０．９９、１．０１になったとしても、上述したように垂直方向、水平方向の振巾は殆ど変化しないのみならず、楕円の回転方向も一定である。従って、従来のように搬送速度を大幅に減少したり搬送方向が逆になったりすることはない。
【００５６】
以上、本発明の各実施の形態について説明したが、勿論、本発明はこれらに限定されることなく、本発明の技術的思想に基づいて種々の変形が明らかである。
【００５７】
例えば以上の実施の形態では、第１の機械振動系３５ａを水平方向の振動系、第２の機械振動系３５ｂを垂直方向の振動系としたがこれを逆としてもよい。
【００５８】
また以上の実施の形態では、第１、第２振動速度検出器３６ａ、３６ｂにより第１、第２機械振動系３５ａ、３５ｂの可動部の振動速度を検出するようにしたが、この振動速度検出器３６ａ、３６ｂに対してそれぞれ振巾検出器と微分器を用いてこの微分器の出力を第１、第２コントローラ３２ａ、３２ｂの比較部に負帰還するようにしてもよい。更に第１、第２振動速度検出器３６ａ、３６ｂに代えて加速度検出器と積分器とを用いてこの積分器の出力を第１、第２コントローラ３２ａ、３２ｂの比較部に負帰還させるようにしてもよい。また以上の実施の形態では第１、第２の振動駆動子３４ａ、３４ｂは第２の実施の形態においては電磁石としたが、その他の駆動子、例えばボイスコイルや圧電素子を用いてもよい。それぞれに位相遅れがあればその分補償するような進み要素をコントローラに内在させるようにすればよい。
【００５９】
なお又、以上の実施の形態では速度フィードバックゲインの大きさを制御系の減数係数ｃ_S を０．２として算出したが、勿論これに限定されることなく、機械振動系の特性に応じて固有振動数が更に大きく変動する場合、あるいは±１％も変動しないような場合には、０．２を更に小さく、例えば０．１、あるいは更に大きく０．３としてもよい。この場合には実際の機械振動系における可動部の速度に比例する力の比例係数は、上記実施の形態では０．０１としたが、勿論、これより大なる場合も小なる場合もあるのでこれに応じて制御を行なって減数係数ｃ_S を定めるようにしてもよい。フィードバックゲインＫ₁ 、Ｋ₂ もこれに応じて変更される。
【００６０】
また、本発明の実施の形態によれば、垂直方向と水平方向の振動の位相差が最適楕円振動では６０度であるが、従来においては機械振動系の固有振動数が垂直方向又は水平方向に僅か変化しただけで位相角は９０度から大きく変化する。この変化量が水平方向、垂直方向に全く同一であれば６０度を保つことができるが、逆方向では倍となり大きな差となる。すなわち図８の楕円振動の説明において、６０度±６０度と変化し最大の６０度の変動においては楕円振動の回転方向が変わるのみならず、水平方向と垂直方向の振動の位相差が１２０度となり、その搬送速度が最適条件における場合より遥かに小さくなる。
【００６１】
なお、垂直方向と水平方向の振動の位相差角の最適位置を６０度としたが、これは実際に各種振動機器において可動部を楕円振動させる場合の通常の振巾において算出されたものであり、更にこれより振巾が大きくなったり小さくなったりする場合には、この最適角６０度から若干変動する。このような場合には上記実施例における位相調節器４０の調節により、例えば振動パーツフィーダの場合にはボウル内のトラックの上の部品の移送速度を観測しながら実測の最適位置を定めるようにしてもよい。
【００６２】
なお、本実施の形態によれば、第１、第２コントローラの比較部にそれぞれ機械振動系の振動速度を負帰還でフィードバックさせているので、上述のような作用、効果を奏するのであるが、更にこのような機械振動系を駆動開始する、すなわち振巾ｒの入力供給を開始する、あるいは振巾指令を０とした場合には、振巾が定常状態になるまでの時間を従来より大幅に短縮することができるのみならず、更に振巾指令を０としてから振巾が０になるまでの時間を従来より大幅に小とすることができるという効果も奏するものである。
【００６３】
【発明の効果】
以上述べたように、本発明の楕円振動装置によれば、垂直振動系も水平振動系も固有振動数又はその近傍で安定に所定の位相差をもって駆動することができる。すなわち常に最適な楕円振動を得ることができ、従って例えば振動機器が楕円振動パーツフィーダであれば、最大の搬送速度で部品を次工程に供給することができる。また、水平、垂直方向共に固有振動数又はその近傍で駆動できるので消費エネルギーを小さくできる。
【図面の簡単な説明】
【図１】本発明の実施の形態による楕円振動装置のブロック図である。
【図２】同要部のブロック図である。
【図３】従来の角周波数と振動伝達特性を示すチャートである。
【図４】本発明の実施の形態における角周波数と振動伝達特性を示すチャートである。
【図５】従来の角周波数と位相角との関係を示すチャートである。
【図６】本発明の実施の形態における角周波数と位相差との関係を示すチャートである。
【図７】本発明の他の実施の形態の楕円振動装置のブロック図である。
【図８】従来例の固有振動数が±１％増大した場合の楕円振動の形状を示すチャートである。
【図９】従来例の振動パーツフィーダの楕円振動の形状を示すチャートである。
【図１０】従来例の振動パーツフィーダの部分破断側面図である。
【図１１】図１０における［１１］−［１１］線方向の断面図である。
【図１２】同振動パーツフィーダの背面図である。
【図１３】従来例の作用を示す周波数と位相関係を示すチャートである。
【符号の説明】
３０ 楕円振動装置
３１ 信号発生器
３２ａ 第１コントローラ
３２ｂ 第２コントローラ
３３ａ 第１電力増巾器
３３ｂ 第２電力増巾器
３４ａ 振動駆動子
３４ｂ 振動駆動子
３５ａ 第１機械振動系
３５ｂ 第２機械振動系
３６ａ 機械振動検出器
３６ｂ 機械振動検出器
５０ 楕円振動装置 [0001]
BACKGROUND OF THE INVENTION
The present invention relates to an elliptical vibration device that supplies parts by vibration, for example.
[0002]
[Prior art]
In FIG. 10, the elliptical vibration parts feeder is generally indicated by 1 and includes a known bowl 2. A spiral track is formed on the inner peripheral surface of the bowl 2, and a wiper is provided at an appropriate position on the downstream side. Although this wiper is already well known and omitted in the drawing, the flat plate is bent, and the distance between the lower end of the wiper and the transport surface of the track is larger than the thickness of the component m (flat plate) to be fed, Smaller than this. At the discharge end of the truck, posture holding means is provided, through which a component in a desired posture (for example, a component m having a long side facing the transfer direction) is supplied to a linear vibration feeder (not shown).
[0003]
  The bowl 2 is fixed to a cross-shaped upper movable frame 7 clearly shown in FIG. 11, and four sets of the upper movable frame 7 which stand upright on the lower movable frame 8 which is also a cross-shaped clearly shown in FIG. They are connected by a laminated leaf spring 9. In other words, the upper end of the overlapping leaf spring 9 is bolted to the four ends 7a of the upper movable frame 7.InThe lower end of the laminated leaf spring 9 is fixed to the four end portions 8a of the lower movable frame 8 with bolts. The end portions 7a and 8a are aligned in the vertical direction.
[0004]
A vertical driving electromagnet 11 is fixed at the center of the fixed frame 10 so as to face the central portion of the upper movable frame 7, and a vertical movable core 13 is fixed to the lower surface of the upper movable frame 7 so as to face the vertical driving electromagnet 11. Has been. In contrast, a pair of horizontal drive electromagnets 14a and 14b are fixed to opposite side walls of the fixed frame 10 with the vertical drive electromagnet 11 interposed therebetween, and coils 15a and 15b are wound around the electromagnets 14a and 14b, respectively. ing. Horizontal movable cores 16a and 16b are fixed to the lower surface of the upper movable frame 7 so as to face the horizontal drive electromagnets 14a and 14b.
[0005]
The fixed frame 10 is integrally formed with four leg portions 17, and these leg portions 17 are supported on the base via vibration-proof rubbers 18. The leg portions 17 are integrally formed with spring mounting portions 17a extending in the lateral direction, and as shown in FIG. 12, the spring mounting portions 17a have four sets of vertical plate springs 19 at both ends. It is fixed with bolts. As shown in FIG. 10, the overlapping leaf springs 19 are overlapped via spacers 20, and their central portions are fixed to the lower movable frame 8 with bolts.
[0006]
In the above configuration, the horizontal drive electromagnets 14a and 14b are first vibration drivers that generate horizontal excitation force, and the first vibration system driven by this is the bowl 2, the leaf spring 9, The electromagnet 11 includes a movable core 16a, 16b, and the like. The electromagnet 11 is a second vibration driver that generates a vertical exciting force. The second vibration system is configured by the bowl 2, the leaf spring 19, the movable core 13, and the like. Is done.
[0007]
In general, a drive current having a frequency equal to or approximately equal to the resonance frequency of the first vibration system in the horizontal direction is supplied to the electromagnets 14a, 14b, and 11, respectively. Frequency f in a state close to this₀ In the vertical direction, the resonance frequency is usually higher by several percent. Therefore, as shown in FIG. 13, in the horizontal direction, the phase difference between force and displacement is delayed by 90 degrees. In the vertical direction, it vibrates with a phase difference different from this, and the elliptical vibration is caused by these phase differences. However, this phase difference is 60 degrees and the optimum condition, that is, the components on the track in the bowl 2 Therefore, the phase difference between the horizontal excitation force and the vertical excitation force is set to be delayed by 150 degrees. That is, as apparent from FIG. 13, the vertical resonance frequency is higher and f₁ Thus, the horizontal and vertical vibration displacements vibrate with a phase delay of 60 degrees.
[0008]
However, as is apparent from vibration engineering, when the vibration system is driven at the resonance frequency, the resonance frequency fluctuates due to slight fluctuations in the power supply or slight changes in the loads on the components in the bowl 2. As a result, the horizontal resonance frequency is f in an empty state where no parts are stored.₀ Even if the phase difference between the force and the displacement is 90 degrees, the phase difference changes greatly due to such fluctuations. Therefore, even if the phase difference does not fluctuate so much in the vertical direction driven by forced vibration. Because of the large fluctuation in the horizontal direction, these phase differences eventually differ from 60 degrees. As a result, the optimum vibration condition for the bowl cannot be obtained. Further, since the vertical vibration system is driven at a frequency several percent lower than its natural frequency, a large amount of energy is required to maintain a predetermined amplitude.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems. Even if there is some fluctuation in the power source, the spring multiplier changes over time, or the load on the components in the bowl changes, the horizontal and vertical resonance frequencies or It is an object of the present invention to provide an elliptical vibration device that can maintain the optimum phase difference angle while being vibrated in the vicinity, and that can reduce the excitation energy.
[0010]
[Means for Solving the Problems]
  The above problems are at least the first comparison unit and the gain K.₁And a gain K for amplifying the output of the first controller.₀The first power amplifier, a first vibration driver that receives the output of the first power amplifier to generate a horizontal vibration force, and the horizontal vibration force of the first vibration driver. Receiving a horizontal vibration system of the elliptical vibrator, first vibration speed detecting means for detecting the horizontal vibration speed of the movable part of the elliptical vibrator, at least a second comparison unit, and a gain K₁And a gain K for amplifying the power of the output of the second controller.₀A second power amplifier, a second vibration driver that generates an excitation force in a vertical direction in response to the output of the second power amplifier, and the vertical vibration of the second vibration driver Connected to a vertical vibration system of the elliptical vibrator receiving force, second vibration speed detecting means for detecting the vertical vibration speed of the movable part of the elliptical vibrator, and a first comparison unit of the first controller. And a phase adjuster connected between the signal generator and the second comparison unit of the second controller, and the first and second comparison units include the first and second speeds, respectively. The output of the detection means is set to a predetermined gain K with respect to the output of the signal generator.₂Negative feedback, and K₀, K₁, K₂Is used to set a damping coefficient of vibration for control, and to obtain a maximum conveyance speed due to elliptic vibration between inputs from the signal generator supplied to the first and second comparison units by the phase adjuster. To set the phase difference to 60 degrees,
  here,Uncontrolled damping coefficient = c
          Damping coefficient by control of movable part M = c_S
          Speed feedback gain = c 'When
          c '= c_S-C = K₁ × K₂ × K₀ To be
K₁ , K₂ , K₀By selecting, the angular frequency and vibration transmission characteristics and the angular frequency and phase difference characteristics before and after the resonance frequency,Each amplitude and phase differenceThe problem is solved by an elliptical vibration device characterized in that it is gradually changed.
[0011]
The first and second vibration systems are vibrated at or near the same natural frequency. The output from the signal generator is supplied as it is to the first comparison unit of the first controller for the first vibration system, and to the second comparison unit of the second controller for the second vibration system via the phase adjuster. Supplied. Since the optimum phase difference angle between the horizontal and vertical is theoretically 60 degrees in elliptical vibration, it is set to 60 degrees. The first vibration system and the second vibration system vibrate naturally at a phase difference angle of 60 degrees adjusted by the phase adjuster at the natural frequency. Even if there is a change over time in the total mass or the spring constant due to some cause of the movable parts of the first and second vibration systems, the amplitude and the phase difference angle hardly change as in the prior art. In other words, the phase difference angle set by the phase adjuster is held at each natural frequency or a driving frequency close to this, so that stable vibration is always performed, and the optimum elliptical vibration can be obtained with the excitation energy almost minimized. it can.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0013]
In FIG. 1, the elliptical vibration device according to the present embodiment is indicated by 30 as a whole, and the output of the signal generator 31 as a signal source is supplied to the first controller 32a. This output is supplied to the first power amplifier 33a, and further this amplified output is supplied to the first vibration driver 34a. The vibration driver 34a causes the first mechanical vibration system, for example, the vertical vibration system in the conventional example, to operate. Driven. The vibration speed of the movable portion in the vertical direction is detected by the first vibration speed detector 36a, and this is negatively fed back to the output of the signal generator 31 to the comparison section of the first controller 32a whose circuit is clearly shown in FIG. The
[0014]
The signal generator 31 is further connected to the second controller 32b via the phase adjuster 40. This output is supplied to the second power amplifier 33b, and this amplified output is further supplied to the second vibration driver 34b. Supplied. A horizontal vibration system 35b is vibrated by the vibration driver 34b. The horizontal vibration speed of the movable portion is detected by a vibration speed detector 36b, and this output is negatively fed back to the output of the phase adjuster 42 to the comparison section of the second controller 32b, the details of which are shown in FIG. The
[0015]
FIG. 2 shows details of the first and second controllers 32a and 32b in FIG. 1 and a mathematical model of the first and second mechanical vibration systems 35a and 35b. The first controller 32a includes a vibration speed detecting means 41 of the mechanical vibration system 35a, which is₂ Is negatively fed back to the first comparator 42 with a voltage. As described above, the output r of the signal generator 31 is supplied to this one end. The difference output of the first comparison unit 42 is K₁ The output xc is supplied to the first power amplifier 33a. This gain is K₀ It is. Since the first and second controllers 32a and 32b have the same configuration, only one 32a will be described.
[0016]
The output of the power amplifier 33a is supplied to the first vibration driver 34a. This excitation force is applied to the movable part M of the first vibration system 35a. The mass of the movable part M is m, the velocity element obtained by integrating this acceleration is 46, and the output of the integrating element 47 obtained by further integration is the amplitude x. If the spring multiplier of the mechanical vibration system 35a is K, the amplitude x is negatively fed back to the movable part M as a comparison part with a gain K. Further, the output of the integrating element 46 becomes a speed, but a force obtained by multiplying this speed by a gain C corresponding to the viscosity coefficient C is also negatively fed back.
[0017]
The above is the differential equation of motion of the vibration system 35a, m (d² x / dt² ) + C (dx / dt) + Kx = excitation force equation. According to the present invention, the output of the integral element 46, that is, the vibration velocity of the movable part M of the mechanical vibration system 35a is determined by the vibration detecting means 41. And gain K₂ Thus, negative feedback is provided to the first comparison unit 42 in the first controller 32a. This is supplied with a predetermined output r of the signal generator 31, and this difference is gained by the first amplifying unit 43 (K₁ ) And then supplied to the power amplifier 33a which is a power amplifier.
[0018]
Next, the operation of the embodiment of the present invention will be described in comparison with the prior art.
[0019]
The ratio between the output r of the signal generator 31 and the amplitude output x of the vibration system 35a is expressed by the equation (1) when expressed in terms of a transfer function in the conventional case.
[0020]
[Expression 1]

[0021]
In the equation (1), s represents the complex frequency jω, but when jω is substituted for s, the equation (2) is obtained.
[0022]
[Expression 2]

[0023]
The ratio | x (jω) / r (jω) | of the input r to the amplitude output x with respect to the actual angular frequency is obtained from the equation (2) as in the equation (3).
[0024]
[Equation 3]

[0025]
In equation (3), m = 1, c = 0.01, K = 1, K₀ Substituting = 1 gives equation (4).
[0026]
[Expression 4]

[0027]
When the equation (4) is plotted, a graph as shown in FIG. 3 is obtained. Next, when the speed feedback controller 32a according to the present invention is used, Expression (5) is obtained.
[0028]
[Equation 5]

[0029]
Substituting jω for s yields equation (6).
[0030]
[Formula 6]

[0031]
From equation (6), the amplitude ratio | x (jω) / r (jω) | of the input and output with respect to the actual angular frequency ω can be expressed as in equation (7).
[0032]
[Expression 7]

[0033]
In equation (7), m = 1, c = 0.01, K = 1, K₀ = 1, K₁ = 20, K₂ Substituting = 0.19 / 20 yields equation (8).
[0034]
[Equation 8]

[0035]
When the equation (8) is plotted with respect to the angular frequency ω, the graph of FIG. 4 is obtained.
[0036]
As described above, the relationship between ω and the amplitude ratio is large as shown in FIGS. 3 and 4 when the conventional speed feedback controller 32a is not used and when the speed feedback controller 32a is used as in the present invention. Is different. In other words, conventionally, ω = 1, that is, in the resonance state, the amplitude ratio is 1 when ω is sufficiently small with respect to 100, that is, when it is far away from the resonance point. That is, while the resonance magnification is 100 times, in the present invention, as shown in FIG. 4, when ω = 1, the amplitude ratio is 100 as in the conventional case, but the angular frequency ω is sufficiently smaller than 1. That is, when the distance is far from the resonance point, the value is 20. Therefore, the resonance magnification is 5. However, when the angular frequency ω is in the vicinity of 1, as shown in FIG. 3 and FIG. That is, when the first mechanical vibration system 35a is a vibration part feeder, for example, when the first mechanical vibration system 35a is a vibration parts feeder, the total mass of the bowl including the workpiece and the total spring constant of the leaf spring that joins the bowl and the base block are changed. Therefore, if the natural frequency changes even slightly, it fluctuates greatly, but in the present invention, it changes only slightly.
[0037]
In the above embodiment, the gain K of the widening portion 43 is₁ And speed feedback gain K₂ Is determined as follows. That is, when it is desired to moderate the change in amplitude ratio x / r and the change in phase near the natural frequency, the damping coefficient of the vibration system may be increased. The coefficient c = 0.01. In contrast, the damping coefficient c of the system is controlled by the control._S = 0.2. That is, the damping coefficient c by the control with respect to the movable part M_S = 0.2, so speed feedback gain c '= c_S -C = 0.2-0.01 = 0.19. That is, in FIG. 2, c ′ = K₁ × K₂ × K₀ (K₀ = 1, c '= K₁ × K₂ ). Resonance magnification = 1 / 2ζ_s = 1 / c_s / (Square root of mK) = 1 / 0.2 = 5 (where m = 1, K = 1).
[0038]
In order to obtain an output of the same amplitude 100 as that at the time of non-control with respect to the input of the amplitude 1 at the natural frequency, it is necessary to apply a gain of 20 times to the input. Therefore, the gain K of the widening portion 43₁ = 20. At this time, K₂ C ′ = K₂ × K₁ From 0.19 = K₂ × 20. Therefore, K₂ = 0.19 / 20. This is the above gain K₁ = 20, K₂ = 0.19 / 20.
[0039]
The embodiment of the present invention is configured and operates as described above. Next, another embodiment will be described.
[0040]
FIG. 7 shows the whole of the elliptical vibration device 50, but portions corresponding to the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. That is, according to the present embodiment, an electromagnet is used for the first vibration driver 51. As is well known, an electromagnet has a coil wound around an iron core and energizes an alternating current to generate an alternating magnetic attractive force with a movable core facing each other with a gap therebetween. In such an actuator, there is a delay element of (1 / R) × (1/1 + Ts). For this reason, even if the vibration speed is fed back from the vibration system, if it is applied to the vibration system as a control force, the above-described operation cannot be performed unless this delay is compensated. (In the above, the delay element is ignored or the vibration driver without the delay element is used.) Therefore, in the present embodiment, the current component i of the electromagnet 51 that is an actuator is detected and converted into a voltage. This is converted and negatively fed back to the third comparison unit 52. In other words, the controller 53a in the present embodiment has a current detection gain Ki and a current feedback gain K._Four And this current feedback gain K_Four Output, ie, a voltage value, is negatively fed back to the third comparison unit 52. There is a delay element of (1 / R) × (1/1 + Ts) between the input e and the output i to the actuator 51. By feedback by this minor loop, the output e of the power amplifier 33a is so-called overexcitation. Is compensated for the delay caused by passing through the actuator 51. As a result, the above-described actions and effects can be obtained with certainty.
[0041]
The phase characteristic in the case where there is no conventional speed feedback controller is expressed by equation (9).
[0042]
[Equation 9]

[0043]
In equation (9), when m = 1, c = 0.01, and K = 1, equation (10) is obtained.
[0044]
[Expression 10]

[0045]
When the speed feedback controller of the present invention is used, the phase characteristic is expressed by the equation (11).
[0046]
## EQU11 ##

[0047]
Similarly, m = 1, c = 0.01, K = 1, K₀ = 1, K₁ = 20, K₂ Substituting = 0.19 / 20 yields equation (12).
[0048]
[Expression 12]

[0049]
With respect to the equations (10) and (12), the plots with the horizontal axis representing the angular frequency ω are shown in FIG. 5 and FIG. 6, but as is apparent from FIG. That is, the phase difference angle G is −90 degrees at the resonance point, but if it changes even slightly, it changes rapidly between 0 degree and 180 degrees. Therefore, in the prior art, when the horizontal vibration system and the vertical vibration system are first driven at the natural frequency and the phase difference between the force and the displacement is −90 degrees, if there is a change with time in the mass or spring constant, FIG. As shown, the phase difference changes abruptly from -90 degrees. As a result, even if the optimal elliptical vibration is initially performed at 60 degrees adjusted by the phase adjuster 40 between the horizontal vibration and the vertical vibration, the 60 degrees is maintained by such a change. However, the amplitude of the vibration is greatly changed and the shape of the elliptical vibration is different, which is far from the optimum elliptical vibration.
[0050]
FIG. 6 is a plot of the phase difference versus angular frequency ω for the present invention, but as is apparent from the figure, the phase difference is −90 degrees at the resonant frequency, ie ω = 1, but the mass and Even if the spring constant changes over time for some reason, the rate of change is smaller than in the prior art. Therefore, if the adjustment is made by the phase adjuster 40 to maintain the optimum phase difference, the horizontal vibration is not readjusted. Optimum elliptical vibration can be obtained by making the phase difference between the vertical vibration and the vertical vibration close to 60 degrees.
[0051]
  Next, FIG. 8 and FIG. 9 show what kind of elliptical vibration changes when the natural frequency is changed between the prior art and the present invention. FIG. 8 shows the prior art. When the natural frequency ωnx of the horizontal component is 1.00, as shown by A, B, and C in FIG. 8, the natural frequency ωny in the vertical direction is It changes to 0.99, 1.00, 1.01, and the direction of the major axis also changes and is opposite to the horizontal direction. The size in the horizontal direction is the same, but the size in the vertical direction is maximum at ωny = 1.00. When ωnx increases or decreases by 1%, that is,0.99And 1.01 show an elliptical shape as shown in the figure as ωny changes to 0.99, 1.00, and 1.01, but when ωnx = 0.99, as shown in FIGS. At ωny = 1.00, the vertical size is maximum, but the horizontal size is not much different from the others. Further, when ωny = 0.99 and 1.01, they have almost the same elliptical shape. When ωnx = 1.01, the vertical size is the maximum at ωny = 1.00, and the horizontal size is not much different. However, in any case, the shape of the ellipse is greatly different. FIG. 9 is a diagram showing a case where ωnx is changed to 0.99, 1.00 and 1.01, and ωny is changed to 0.99, 1.00 and 1.01 in the embodiment of the present invention. As shown in the figure, the elliptical shape hardly changes. Therefore, as described above, in the present invention, it is clear that optimum elliptical vibration is always performed even if the natural frequency changes with time. Further, even if the phase difference between the vibrations in the horizontal direction and the vertical direction is conventionally set to 60 degrees in the past, when the natural frequency increases or decreases by ± 1%, it varies by ± 60 degrees, whereas in the present invention, it is ± 6 degrees. Degree. Therefore, it is clear that the phase difference angle can always be kept at 60 degrees or in the vicinity thereof, and the optimum elliptical vibration can always be obtained.
[0052]
In the prior art, when the horizontal natural frequency ωnx changes, the horizontal amplitude changes greatly. When ωnx = 1.00 and ωny = 1.00, both horizontal and vertical amplitudes are 100. However, when ωny = 1.00 and ωnx = 0.99, or ωnx = 1.01. As shown in FIG. B, the vertical amplitude remains 100, but the horizontal amplitude is about 45 respectively. The same is apparent from FIGS. 8A and 8C when ωny = 0.99 and 1.01. In any case, when both ωnx and ωny change from 1.00, it can be seen that both the horizontal and vertical amplitudes change greatly. However, in the present invention, as is clear from FIG. 9, even if ωnx and ωny are changed from 1.00 to 0.99 or 1.01, the amplitudes in the vertical and horizontal directions hardly change.
[0053]
Note that the phase difference between the force and the displacement is apparent from the equations (10) and (12), and as is apparent from the plotted FIG. 5 and FIG. 6, the natural vibrations in both the vertical and horizontal directions. When the number increases or decreases by ± 1%, the present invention hardly changes from 90 degrees, and as described above, the phase difference of vibration between the horizontal direction and the vertical direction can be 60 degrees ± 6 degrees. Therefore, optimal elliptical vibration can be obtained. On the other hand, in the related art, the phase difference of vibration greatly changes from 90 degrees and is 60 degrees ± about 60 degrees between the vertical and horizontal directions, and the optimum elliptical vibration cannot be obtained.
[0054]
In the above, the first mechanical vibration system 35a, that is, the horizontal vibration system has been described. Of course, the same can be said for the vertical vibration system. Therefore, the graphs showing the phase characteristics and gain characteristics are horizontal and vertical. It is also common.
[0055]
In addition, in the elliptical vibration that does not use the conventional speed feedback shown in FIG. 8, when ωnx and ωny increase or decrease by ± 1% from the natural vibration frequency, the shape, the vertical amplitude, and the horizontal amplitude also vary greatly. Furthermore, there is a difference in the rotation direction of the ellipse, that is, whether the loop rotates clockwise or the loop rotates counterclockwise. In some cases, this may cause the parts to be transported on the track in the opposite direction, which is of course significantly less than the conveying speed in the optimal elliptical vibration. On the other hand, when the speed feedback of the present application shown in FIG. 9 is applied, even if ωnx and ωny increase / decrease ± 1% from 1 of the natural frequency to become 0.99 and 1.01, respectively. Thus, the amplitude in the vertical and horizontal directions hardly changes, and the rotation direction of the ellipse is also constant. Therefore, the transport speed is not significantly reduced and the transport direction is not reversed as in the prior art.
[0056]
As mentioned above, although each embodiment of this invention was described, of course, this invention is not limited to these, A various deformation | transformation is clear based on the technical idea of this invention.
[0057]
For example, in the above embodiment, the first mechanical vibration system 35a is a horizontal vibration system and the second mechanical vibration system 35b is a vertical vibration system, but this may be reversed.
[0058]
In the above embodiment, the vibration speeds of the movable parts of the first and second mechanical vibration systems 35a and 35b are detected by the first and second vibration speed detectors 36a and 36b. The outputs of the differentiators may be negatively fed back to the comparison units of the first and second controllers 32a and 32b using amplitude detectors and differentiators for the devices 36a and 36b, respectively. Further, instead of the first and second vibration velocity detectors 36a and 36b, an acceleration detector and an integrator are used, and the output of the integrator is negatively fed back to the comparison unit of the first and second controllers 32a and 32b. May be. In the above embodiment, the first and second vibration drivers 34a and 34b are electromagnets in the second embodiment. However, other drivers such as a voice coil and a piezoelectric element may be used. If there is a phase lag in each of the controllers, a lead element that compensates for that may be included in the controller.
[0059]
In the above embodiment, the magnitude of the speed feedback gain is set to the reduction coefficient c of the control system._S However, the present invention is not limited to this, and is not limited to this. If the natural frequency fluctuates further according to the characteristics of the mechanical vibration system or does not fluctuate by ± 1%, it is 0. .2 may be made smaller, for example, 0.1, or even larger, 0.3. In this case, the proportionality factor of the force proportional to the speed of the movable part in the actual mechanical vibration system is set to 0.01 in the above embodiment, but of course, it may be larger or smaller than this. The reduction coefficient c is controlled according to_S May be determined. Feedback gain K₁ , K₂ Is also changed accordingly.
[0060]
Further, according to the embodiment of the present invention, the phase difference between the vibration in the vertical direction and the horizontal direction is 60 degrees in the optimal elliptical vibration, but conventionally, the natural frequency of the mechanical vibration system is in the vertical direction or the horizontal direction. The phase angle changes greatly from 90 degrees with a slight change. If the amount of change is exactly the same in the horizontal and vertical directions, 60 degrees can be maintained, but in the reverse direction, the difference is doubled, resulting in a large difference. That is, in the explanation of the elliptical vibration in FIG. 8, the rotation direction changes to 60 ° ± 60 ° and the maximum 60 ° fluctuation not only changes the rotation direction of the elliptical vibration, but also the horizontal and vertical vibration phase difference is 120 °. Therefore, the conveyance speed is much smaller than that in the optimum condition.
[0061]
Although the optimum position of the phase difference angle between the vertical and horizontal vibrations is set to 60 degrees, this is calculated with a normal amplitude when the movable part is actually subjected to elliptical vibration in various vibration devices. Further, when the amplitude becomes larger or smaller than this, the optimum angle varies slightly from 60 degrees. In such a case, by adjusting the phase adjuster 40 in the above embodiment, for example, in the case of a vibration parts feeder, the optimum position for actual measurement is determined while observing the transfer speed of the parts on the track in the bowl. Also good.
[0062]
According to the present embodiment, since the vibration speed of the mechanical vibration system is fed back by negative feedback to the comparison units of the first and second controllers, the above-described operations and effects are achieved. Furthermore, when driving such a mechanical vibration system is started, that is, when the input of the amplitude r is started or the amplitude command is set to 0, the time until the amplitude becomes steady is significantly longer than before. In addition to being able to shorten the time, there is also an effect that the time from when the amplitude command is set to 0 to when the amplitude becomes 0 can be significantly reduced as compared with the prior art.
[0063]
【The invention's effect】
As described above, according to the elliptical vibration device of the present invention, both the vertical vibration system and the horizontal vibration system can be stably driven with a predetermined phase difference at or near the natural frequency. That is, optimal elliptical vibrations can always be obtained. Therefore, for example, if the vibration device is an elliptical vibration parts feeder, the parts can be supplied to the next process at the maximum conveyance speed. Further, since it can be driven at or near the natural frequency in both the horizontal and vertical directions, energy consumption can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram of an elliptical vibration device according to an embodiment of the present invention.
FIG. 2 is a block diagram of the main part.
FIG. 3 is a chart showing a conventional angular frequency and vibration transfer characteristics.
FIG. 4 is a chart showing angular frequency and vibration transfer characteristics in the embodiment of the present invention.
FIG. 5 is a chart showing a relationship between a conventional angular frequency and a phase angle.
FIG. 6 is a chart showing the relationship between angular frequency and phase difference in the embodiment of the present invention.
FIG. 7 is a block diagram of an elliptical vibration device according to another embodiment of the present invention.
FIG. 8 is a chart showing the shape of elliptical vibration when the natural frequency of the conventional example is increased by ± 1%.
FIG. 9 is a chart showing the shape of elliptical vibration of a vibration part feeder of a conventional example.
FIG. 10 is a partially broken side view of a vibration part feeder of a conventional example.
11 is a cross-sectional view taken along line [11]-[11] in FIG.
FIG. 12 is a rear view of the vibration parts feeder.
FIG. 13 is a chart showing the relationship between frequency and phase showing the operation of the conventional example.
[Explanation of symbols]
  30 Elliptical vibration device
  31 Signal generator
  32a first controller
  32b Second controller
  33a First power amplifier
  33b Second power amplifier
  34a Vibration driver
  34b Vibration driver
  35a First mechanical vibration system
  35b Second mechanical vibration system
  36a Mechanical vibration detector
  36b Mechanical vibration detector
  50 Elliptical vibration device

Claims (3)

A first controller having at least a first comparison unit and the first Zohaba portion of the gain K _1, a first power increasing width instrument gain K ₀ for power increasing width the output of the first controller, the first power up A first vibration driver that generates an excitation force in the horizontal direction in response to an output of the width device; a horizontal vibration system of an elliptical vibrator that receives the horizontal excitation force of the first vibration driver; and the elliptic vibration a first vibration velocity detecting means for detecting the vibration velocity of the horizontal direction of the movable portion of the machine, at least a second comparator unit, and a second controller having a second Zohaba portion of the gain K _1, the second controller output A second power amplifier with a gain K ₀ that amplifies the power of the power, a second vibration driver that generates an exciting force in a vertical direction by receiving the output of the second power amplifier, and the second vibration drive A vertical vibration system of the elliptical vibrator that receives the vertical excitation force of the child, and the elliptical vibration A second vibration speed detecting means for detecting the vibration speed in the vertical direction of the movable portion, a signal generator connected to the first comparison section of the first controller, and a second generator of the signal generator and the second controller. A phase adjuster connected between the first and second comparators, the outputs of the first and second speed detectors being respectively given to the first and second comparators with respect to the output of the signal generator. Negative feedback is performed with a gain K ₂ , a damping coefficient of vibration for control is set with the K ₀ , K ₁ , K ₂ , and the phase adjuster supplies the first and second comparison units A phase difference of 60 degrees for obtaining the maximum conveyance speed due to elliptical vibration is set between the inputs from the signal generator,
Here, the uncontrolled damping coefficient = c
Attenuation coefficient by controlling the movable part M = c _S
When the velocity feedback gain = c ',
The choice of _{c '= c S -c = K} 1 × K 2 × <br/> made to be K ₀ the _{K 1, K 2, K 0} , the vibration transmission characteristic and the angular frequency and the phase difference between the angular frequency An elliptical vibration device characterized in that the amplitude and phase difference are gradually changed before and after the resonance frequency in characteristics.   2. The elliptical vibration device according to claim 1, wherein each of the first and second controllers further includes a phase advance element for compensating for a delay element of the first and second vibration drivers. The first and second controllers further receive the outputs of the first and second amplifiers, respectively, and third and fourth comparison units, and third and fourth current detection units of the first and second vibration drivers. have, third, the first output of the fourth current detector current gain Ki and the current feedback gain K ₄ as a voltage value, to the output of the second Zohaba portion, the third, fourth The elliptical vibration device according to claim 2, wherein negative feedback is made to the comparison unit.

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