JP2004007890A - Method and apparatus for drive controlling for linear vibrating motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain position information and speed information in a vibrator with accuracy without providing an off duration during which a driving current for excitation is not fed through the winding of a stator, unlike conventional cases, and thus control driving of a linear vibrating motor with higher efficiency than ever. <P>SOLUTION: The winding 5a of electromagnets constituting the stator 5 is supplied with a driving current to cause the vibrator 6 to linearly vibrate to the stator 5. At this time, a current fed through the winding 5a of the stator 5 and voltage induced in the winding are detected by detection units 11 and 12, respectively. In a control circuit part 13, induced voltages induced with vibration of the vibrator 6 are sequentially computed from the detected current value and voltage value based on a predetermined computing equation. Then, the computed values of induced voltage are smoothed to obtain an approximation function. Position information and speed information in the vibrator 6 are acquired from the approximation function. Based on these information, a driving current to be supplied to the winding 5a of the stator 5 is PWM-controlled through a control output part 14. <P>COPYRIGHT: (C)2004,JPO

Description

【００４１】
なお、ノイズの除去処理の内容については後に詳述する。また、振動子６の１往復期間内に電流と電圧を検出する場合のサンプリング間隔およびサンプリング数が一定になるように予め固定しておけば、後述の（式２）に基づいて近似関数を求める場合の演算処理において定数化が可能になるので、演算が容易になる。
【００４２】
上記の（式１）に基づいて得られる誘起電圧演算値は、滑らかな曲線とはならず凹凸が激しいので、このままでは正弦波状の誘起電圧の最大値、最小値およびゼロクロス点を確定することが難しい。そこで、（式１）により得られた各々の誘起電圧演算値ｙは、次段の近似関数演算部２２に送出される。近似関数演算部２２は、誘起電圧演算値ｙをスムージング化するために、最小２乗法を用いて各誘起電圧演算値ｙを近似した近似関数ｐ（ｘ）（図４（ｆ）参照）を（式２）に基づいて求める（Ｓ０３）。すなわち、この場合の（式２）は３次関数ｐ（ｘ）であるので、その３次関数ｐ（ｘ）を規定する各係数ｂ０〜ｂ３を求める。このように、近似関数ｐ（ｘ）を求めることにより、誘起電圧推定値ｙがスムージング化されるため、誘起電圧の最大値、最小値およびゼロクロス点を確定するのが容易になる。
【００４３】
【式２】

【００４４】
なお、近似関数ｐ（ｘ）としては、三角関数の適用も可能ではあるが、この実施の形態のように３次関数ｐ（ｘ）を近似関数として求める方が演算処理の負担が少なくて済み、また、振動子６の往復動作時に加わる負荷が非対称の場合でも近似が可能となるため有利である。
【００４５】
引き続き、この近似関数ｐ（ｘ）の各係数ｂ０〜ｂ３のデータが動作状態検出部２３に送出されるので、動作状態検出部２３は、（式２）で示される近似関数ｐ（ｘ）から振動子６の位置情報および速度情報を得る（Ｓ０４）。例えば、近似関数ｐ（ｘ）の値が正負反転するゼロクロス点を求め、このゼロクロス点を振動子６の振動方向が切り替わる折り返し点として判断してその位置情報を得る。また、近似関数ｐ（ｘ）の１周期内の値の内で最大値を振動子６の速度が最大になっていると判断してその速度情報を得る。
【００４６】
こうして、動作状態検出部２３で検出された振動子６の位置情報および速度情報は、制御演算部２４に送出される。制御演算部２４は、これらの情報に基づいて固定子５の巻線５ａへの駆動電流をＰＷＭ制御するための信号出力タイミングやパルス幅を決定し、その情報を駆動出力部１４に出力する（Ｓ０５）。駆動出力部１４は、制御回路部１３からの情報に基づいてＰＷＭ制御された駆動電流を固定子５の巻線５ａに供給する。これにより、振動子６は、動作方向と駆動方向とが同調されるとともに、外部負荷の大きさによらず常に一定の速度を保つように駆動制御される。
【００４７】
ここで、図３に示すように、上述した電流検出部１１と電圧検出部１２により電流及び電圧を検出して誘起電圧演算部２１により誘起電圧を演算して誘起電圧演算値ｙを得るまでの処理（Ｓ０１及びＳ０２）を処理１とし、近似関数演算部２２により近似関数ｐ（ｘ）を算出して動作状態検出部２３により振動子６の位置情報および速度情報を得るまでの処理（Ｓ０３及びＳ０４）を処理２とし、制御演算部２４により駆動電流をＰＷＭ制御する処理（Ｓ０５）を処理３と定義する。また、振動子６の３往復期間を１周期とみなした場合の各々の１往復期間をＴｓ１，Ｔｓ２，Ｔｓ３と区別する。
【００４８】
このとき、期間Ｔｓ１で誘起電圧演算部２１が処理１を実行し、次の期間Ｔｓ２で近似関数演算部２２と動作状態検出部２３とで処理２を実行し、さらに次の期間Ｔｓ３で制御演算部２４が処理３を実行するようなシーケンスにすると、一つの処理の実行中には他の処理が停止しているため、振動子６の３往復期間（＝Ｔｓ１＋Ｔｓ２＋Ｔｓ３）ごとにしか適切にＰＷＭ制御された駆動信号を出力することができない。つまり、振動子６を駆動制御に時間がかかり過ぎて、駆動制御処理の高速化を図ることができない。
【００４９】
これに対して、図５に示すように、各期間Ｔｓ１、Ｔｓ２、Ｔｓ３において、各処理１、２、３が同時並列的に行なわれるようにすれば、振動子６の１往復期間Ｔｓ１、Ｔｓ２、Ｔｓ３毎に適切にＰＷＭ制御された駆動信号を出力することができる。もっとも、処理１の結果が得られないと処理２が、処理２の結果が得られないと処理３が、それぞれ実行できないので、各部２１〜２４の内部にその処理結果を記憶する図示しないメモリを設けておき、たとえば期間Ｔｓ３で誘起電圧演算部２１が処理１を実行している場合には、近似関数演算部２２と動作状態検出部２３とは、その１期間前の期間Ｔｓ２で得られた処理１の結果に基づいて処理２を実行し、制御演算部２４はその２期間前の期間Ｔｓ１で得られた処理１の結果に基づいて処理３を実行できるようにする必要がある。このように、振動子６の１往復期間Ｔｓ１、Ｔｓ２、Ｔｓ３、…ごとに処理１、２、３を同時並列的に行なうには、各処理１〜３の切り替わりのタイミングを設定する必要がある。そのため、全体制御部２５には図５に示すような互いに連動する３つのタイマ１〜３（Ｚ１〜Ｚ３）を設けている。
【００５０】
すなわち、図６に示すように、タイマ１（Ｚ１）は、タイマ２（Ｚ２）からのトリガ信号に応答して計時を開始するとともに、処理１の実行開始のトリガ信号を出力し、期間Ｔｓ１が経過すると処理２の実行開始のトリガ信号を出力し、期間Ｔｓ２が経過すると処理３の実行開始のトリガ信号を出力するとともに、タイマ３（Ｚ３）に計時開始のトリガ信号を出力する。タイマ３（Ｚ３）は、タイマ１（Ｚ１）からのトリガ信号に応答して計時を開始するとともに、処理１の実行開始のトリガ信号を出力し、期間Ｔｓ３が経過すると処理２の実行開始のトリガ信号を出力し、期間Ｔｓ１が経過すると処理３の実行開始のトリガ信号を出力するとともに、タイマ２（Ｚ２）に計時開始のトリガ信号を出力する。また、タイマ２（Ｚ２）は、タイマ３（Ｚ３）からのトリガ信号に応答してして計時を開始するとともに、処理１の実行開始のトリガ信号を出力し、期間Ｔｓ２が経過すると処理２の実行開始のトリガ信号を出力し、期間Ｔｓ３が経過すると処理３の実行開始のトリガ信号を出力するとともに、タイマ１（Ｚ１）に計時開始のトリガ信号を出力する。
【００５１】
これにより、図６に示すように、各期間Ｔｓ１，Ｔｓ２，Ｔｓ３において、各処理１、２、３が同時並列的に行なわれるようになり、処理１〜処理３が間断なく実行される。このため、固定子５の巻線５ａの電流および電圧を検出してから振動子６の駆動電流を制御するまでに要する時間を全体として短縮化でき、駆動制御処理の高速化を図ることができる。
【００５２】
図７は上記の図５及び図６で説明した各タイマ１〜３の動作をより詳細に表したタイミングチャート、図８ないし図１０は上記の図３に示したリニア振動モータの駆動制御動作をより詳細に表したフローチャートであり、図８はタイマ１（Ｚ１）に着目したときの、図９はタイマ２（Ｚ２）に着目したときの、図１０はタイマ３（Ｚ３）に着目したときの、各動作をそれぞれ示している。
【００５３】
ここで、例えば、タイマ１（Ｚ１）に着目すると、図８においてステップ１、２、９が図３の処理１に対応し、ステップ３が図３の処理２に対応し、ステップ４〜ステップ８が図３の処理３に対応している。そして、タイマ２（Ｚ２）からのトリガ信号によりカウンタ値がクリアされて計時を開始し、その後、時刻ｔ１−２で処理１が終了すると、時刻ｔ１−３までの間に処理２を実行し、時刻ｔ１−３でタイマ３（Ｚ３）にトリガ信号を出力し、時刻ｔ１−４〜時刻ｔ１−７の期間に処理３を実行する。なお、図９および図１０についても図８の場合の処理と同様であるからここでは詳しい説明は省略する。
【００５４】
図１１は、図３の処理１（Ｓ０２）において、誘起電圧演算部２１が各検出部１１、１２で検出された電流値と電圧値をサンプリングした際に含まれるノイズ成分を取り除くための具体的な処理内容を示すフローチャートである。誘起電圧演算部２１は、まず、電流検出部１１と電圧検出部１２でそれぞれ検出された電流値と電圧値をサンプリングすると（Ｓ１、Ｓ２）、次に、このサンプリングのタイミングが固定子５の巻線５ａに対して駆動電流が供給されている期間Ｔｈ、Ｔｌ（図４（ａ）参照）か否かを判断する（Ｓ３）。
【００５５】
巻線５ａに対して駆動電流が供給されていない期間であると、サンプリングして得られた巻線５ａに流れる電流値の絶対値が所定のしきい値Ｉｈ以下であるか否かを判断する（Ｓ４）。そして、サンプリングされた電流値の絶対値が所定のしきい値Ｉｈ以下である場合には、次の駆動電流が供給されるまでは、電流値を強制的に零に固定する（Ｓ６）。また、Ｓ４において、サンプリングされた電流値の絶対値が所定のしきい値Ｉｈよりも大きい場合には、前回のサンプリングによれ得られた電流値が零であるか否かを判断する（Ｓ５）。前回のサンプリングによれ得られた電流値が零であるときには、今回のサンプリングで得られた電流値もノイズである可能性が高いので、この場合には、Ｓ６に移行して電流値を強制的に零に固定する。これに対して、Ｓ５で前回のサンプリングで得られた電流値が零でない場合には、今回のサンプリングで得られた電流値はノイズではないと見なせるのでＳ７に移行する。
【００５６】
また、Ｓ３において、電流値をサンプリングしたタイミングが固定子５の巻線５ａに対して駆動電流が供給されている期間内Ｔｈ、Ｔｌ内である場合には、Ｓ７に移行して、その電流の絶対値を前回サンプリングして得られた電流の絶対値と比較する。
【００５７】
ここで、今回サンプリングした電流の絶対値が前回サンプリングして得られた電流の絶対値よりも小さい場合には、駆動電流が供給されている期間中であるにもかかわらず、検出された電流値は単純増加または単純減少しておらず異常と考えられる。そのため、前回サンプリングして得られた電流値を採用する（Ｓ８）。これに対して、今回サンプリングした電流の絶対値が前回サンプリングして得られた電流の絶対値よりも大きい場合には、駆動電流が供給されている期間中に検出された電流値は単純増加または単純減少していると考えられるため、今回サンプリングした電流をそのまま採用する。これにより、電流検出における耐ノイズ性が向上し、誘起電圧演算値ｙを算出する際の精度も向上する。
【００５８】
引き続き、誘起電圧演算部２１は、今回のサンプリングにより検出された誘起電圧と前回のサンプリングにより検出された誘起電圧との差の絶対値を予め設定されたしきい値Ｖｈと比較する（Ｓ９）。
【００５９】
このとき、両誘起電圧の差の絶対値がしきい値Ｖｈ以下である場合には、今回サンプリングした誘起電圧の値をそのまま採用して（式１）に基づいて誘起電圧の演算を行う（Ｓ１０）。これに対して、前後にサンプリングした誘起電圧の差の絶対値がしきい値Ｖｈよりも大きい場合には、ノイズの影響が大きいものと判断して（式１）による誘起電圧の演算を行わず、その代わりに、今回のサンプリングよりも以前のサンプリング時に算出された誘起電圧の値から推定した誘起電圧値を採用する（Ｓ１１）。この場合の誘起電圧推定値は、たとえば、前回と前前回に得られた誘起電圧演算値の加算平均や相乗平均を求めたり、前回得られた誘起電圧演算値と置換したりすることにより算出される。これにより、誘起電圧演算値から近似関数を求める場合のスムージング化が一層促進され、近似関数を求める場合の精度が向上する。
【００６０】
図１２は、図３の処理２（Ｓ０４）において、動作状態検出部２３が（２）式の近似関数ｐ（ｘ）に基づいて振動子６の位置情報と速度情報を得る場合の具体的な処理内容を示すフローチャートである。
【００６１】
ここでは、近似関数ｐ（ｘ）の値が正負反転するゼロクロス点を求め、このゼロクロス点を振動子６の振動方向が切り替わる折り返し点として判断してその位置情報を得ている。また、近似関数の１周期内の値の内で最大値を振動子６の速度が最大になっていると判断してその速度情報を得ている。このようにすれば、近似関数ｐ（ｘ）のピーク探索を一カ所のみ行えば良いので、速度情報を得るための処理が容易になる。
【００６２】
以上のように、この実施の形態によれば、電圧検出部１２で検出される電圧が駆動電流の供給により巻線５ａに生じる印加電圧と振動子６の往復動作に伴って巻線５ａに生じる誘起電圧とが重畳したものであっても、（式１）に示す演算式で誘起電圧ｙを演算することにより印加電圧の影響を実質的に取り除くことができる。このため、巻線５ａに駆動電流が流れている期間中にも巻線５ａに生じる誘起電圧を確実に検出することができる。さらに、誘起電圧演算値ｙをスムージング化した近似関数ｐ（ｘ）を求めるので、粗いサンプリング周期で得られたデータからでも連続した誘起電圧を算出することができる。このため、振動子の位置および速度の検出を精度良く行える。
【００６３】
したがって、従来のように固定子５の巻線５ａに励磁用の駆動電流を流さないオフ期間Ｔ１、Ｔ２を設ける必要性がなくなるため、より一層効率の良い駆動制御が可能になるのである。
【００６４】
上記の実施の形態では、図１２に示したように、近似関数の１周期内の最大値を振動子６の速度情報として得るようにしたが、図１３〜図１５の各フローチャートに示すような処理によって振動子６の位置情報や速度情報を得ることも可能である。
【００６５】
すなわち、図１３に示すフローチャートの処理では、近似関数ｐ（ｘ）の値が正負反転するゼロクロス点を振動子６の振動方向が切り替わる折り返し点として判断してその位置情報を得ている。また、近似関数ｐ（ｘ）の１周期内の最大値と最小値の差を求め、その差を振動子６の速度情報として得ている。これにより、振動子６が振動する際に、その振幅が一方に片寄っている場合にも速度情報を正確に検出することが可能になる。
【００６６】
図１４に示すフローチャートの処理では、誘起電圧演算値を求める範囲を制限し、この制限された演算範囲内でのみ近似関数を求め、次にこの近似関数の絶対値の小さい方のサンプリング時間を近似関数の値が正負反転するゼロクロス点として決定し、このゼロクロス点を振動子６の振動方向が切り替わる折り返し点として判断してその位置情報を得ている。
【００６７】
また、こうして求めたゼロクロス点における微分値を算出し、この微分値を振動子６の速度情報として得ている。このように、誘起電圧演算値を求める範囲を制限することにより、振動子６の位置情報を得る場合の演算数が少なくなるで、演算の負荷を減らすことができるために有利である。しかも、ゼロクロス点における微分値を振動子６の速度情報として得る場合には、振動子６の速度検出精度が高くなり、また、演算も容易に行うことができる。
【００６８】
なお、ゼロクロス点における微分値を振動子６の速度情報として得る代わりに、例えば、近似関数の値が正負反転するゼロクロス点付近において近似関数を直線近似し、その近似直線の傾きを振動子６の速度情報として得ることもできる。その場合には、近似関数の値を求める際に演算誤差が生じても直線近似を行うことで演算誤差による影響を少なくしてより精度良く速度を検出することが可能になる。
【００６９】
図１５に示すフローチャートの処理では、近似関数ｐ（ｘ）の値が正負反転するゼロクロス点を振動子６の振動方向が切り替わる折り返し点として判断してその位置情報を得ている。また、振動子６の１往復期間に相当する期間にわたって誘起電圧演算値の値を順次加算し、その加算値を振動子６の速度情報として得ている。これは正弦波状の誘起電圧の１周期分の面積を求めることに相当するが、この面積計算は単に誘起電圧演算値の値を順次加算するだけでよく、近似関数のピーク位置を求める必要がないため、演算時間を速めることができる。
【００７０】
さらに、本発明は、上記の実施の形態に示した方法や構成に限定されるものではなく、本発明の趣旨を逸脱しない範囲で適宜変更を加えることが可能である。
【００７１】
【発明の効果】
請求項１記載の発明に係るリニア振動モータの駆動制御方法によれば、巻線に生じた電圧が、駆動電流の供給により生じる印加電圧と振動子の往復動作に伴って巻線に生じる誘起電圧とが重畳したものである場合でも、演算式で誘起電圧を演算することにより印加電圧の影響を実質的に取り除くことができる。これにより、巻線に駆動電流が流れている期間中にも巻線に生じる誘起電圧を確実に検出することができる。そして、誘起電圧演算値をスムージング化した近似関数を求めるため、粗いサンプリング周期で得られたデータからでも連続した誘起電圧を算出することができる。これにより、近似関数から振動子の位置情報および速度情報を精度良く得ることができる。したがって、従来のように固定子の巻線に励磁用の駆動電流を流さないオフ期間を設ける必要性がなくなり、より一層効率の良い駆動制御が可能になる。
【００７２】
請求項２記載の発明に係るリニア振動モータの駆動制御方法によれば、請求項１記載の発明の効果に加えて、前記電流および電圧を検出して誘起電圧を演算する処理１と、前記誘起電圧演算値から近似関数を求めて振動子の位置情報及び速度情報を得るまでの処理２と、前記振動子の位置情報および速度情報に基づいて巻線の駆動電流を制御する処理３とを、振動子の１往復期間内に同時並列的に行うようにしているので、上記の処理１〜処理３が間断なく実行される。これにより、巻線の電流および電圧を検出してから振動子の駆動電流を制御するまでに要する時間を全体として短縮化でき、駆動制御処理の高速化を図ることが可能になる。
【００７３】
請求項３記載の発明に係るリニア振動モータの駆動制御方法は、請求項１または２に記載の発明の効果に加えて、誘起電圧演算値をスムージング化する場合に最小２乗法を用いた３次関数で近似するので、三角関数を近似関数として用いる場合よりも演算処理の負担が少なくて済み、また、振動子の往復時の負荷が非対称の場合でも近似が可能となる。
【００７４】
請求項４記載の発明に係るリニア振動モータの駆動制御方法は、請求項１ないし３のいずれかに記載の発明の効果に加えて、振動子の１往復期間内に前記電流と電圧を検出する場合のサンプリング間隔およびサンプリング数が常に一定となるように固定化されているので、近似関数を求める演算処理において定数化が可能になり、演算処理が一層容易になる。
【００７５】
請求項５記載の発明に係るリニア振動モータの駆動制御方法は、請求項１ないし４のいずれかに記載の発明の効果に加えて、電磁石の巻線に対して駆動電流が供給されていない期間にノイズが含まれている場合には、これを強制的に零にするので、電流検出における耐ノイズ性が向上し、誘起電圧演算値を算出する際の精度が向上する。
【００７６】
請求項６記載の発明に係るリニア振動モータの駆動制御方法は、請求項１ないし５のいずれかに記載の発明の効果に加えて、電磁石の巻線に対して駆動電流が供給されている期間内にサンプリングした電流値がしきい値以上である場合にはノイズと見なしてその前にサンプリングしたデータに置き換えるので、電流検出における耐ノイズ性がさらに向上し、誘起電圧演算値を算出する際の精度が向上する。
【００７７】
請求項７記載の発明に係るリニア振動モータの駆動制御方法は、請求項１ないし６のいずれかに記載の発明の効果に加えて、巻線に生じる電圧をサンプリングして得られた電圧値が所定のしきい値以上である場合にはノイズと見なして誘起電圧の演算を行わずに、そのサンプリング以前に算出された誘起電圧演算値から今回の起電圧値を推定するため、誘起電圧演算値から近似関数を求める場合のスムージング化が一層促進され、近似関数を求める場合の精度が向上する。
【００７８】
請求項８記載の発明に係るリニア振動モータの駆動制御方法は、請求項１ないし７のいずれかに記載の発明の効果に加えて、誘起電圧演算値から近似関数を求める場合の演算範囲を制限してその制限された演算範囲内で近似関数の値が正負反転するゼロクロス点を求めるので、振動子の位置情報を得る場合の演算数が少なくなり、演算処理の負荷を減らすことができ、演算処理の高速化を図ることができる。
【００７９】
請求項９記載の発明に係るリニア振動モータの駆動制御方法は、請求項１ないし請求項８のいずれかに記載の発明の効果に加えて、近似関数の１周期内の値の内で最大値を振動子の速度情報として得るので、近似関数のピーク探索を１カ所だけ行うだけで容易に速度情報を得ることができる。
【００８０】
請求項１０記載の発明に係るリニア振動モータの駆動制御方法は、請求項１ないし請求項８のいずれかに記載の発明の効果に加えて、近似関数の１周期内の値の内で最大値と最小値の差を振動子の速度情報として得るようにしているので、振動子が振動する際に、その振幅が片方に片寄っている場合にも速度情報を正確に検出することが可能になる。
【００８１】
請求項１１記載の発明に係るリニア振動モータの駆動制御方法は、請求項１ないし請求項８のいずれかに記載の発明の効果に加えて、近似関数の値が正負反転するゼロクロス点における微分値を振動子の速度情報として得るようにしているので、振動子の速度検出精度が高くなり、また、演算も容易に行える。
【００８２】
請求項１２記載の発明に係るリニア振動モータの駆動制御方法は、請求項１ないし請求項８のいずれかに記載の発明の効果に加えて、近似関数の値が正負反転するゼロクロス点付近において近似関数を直線近似し、その近似直線の傾きを振動子の速度情報として得るようにしたので、近似関数の値を求める際に演算誤差が生じても直線近似を行うことで演算誤差による影響を少なくしてより精度良く速度を検出することが可能になる。
【００８３】
請求項１３記載の発明に係るリニア振動モータの駆動制御方法は、請求項１ないし請求項８のいずれかに記載の発明の効果に加えて、振動子の１往復期間に相当する期間にわたって前記誘起電圧演算値の値を順次加算することで正弦波状の誘起電圧の１周期分の面積を求め、その値を振動子の速度情報として得るようにしたので、速度情報を得るための処理は単なる加算処理でよく、近似関数のピーク位置を求める必要がないため、演算時間の高速化を図ることができる。
【００８４】
請求項１４記載の発明に係るリニア振動モータの駆動制御装置は、請求項１記載の発明の場合と同様、巻線に駆動電流が流れている期間中にも巻線に生じる誘起電圧を確実に検出することができるので、従来のように固定子の巻線に励磁用の駆動電流を流さないオフ期間を設ける必要性がなくなり、より一層効率の良い駆動制御が可能になる。
【００８５】
請求項１５記載の発明に係るリニア振動モータの駆動制御装置は、請求項１４記載の発明の効果に加えて、処理１〜処理３の実行タイミングを規制するタイマ手段を備えることで、請求項２の発明と同様、処理１〜処理３が間断なく実行されるようになるため、巻線の電流および電圧を検出してから振動子の駆動電流を制御するまでに要する時間を全体として短縮化でき、駆動制御処理の高速化を図ることが可能になる。
【図面の簡単な説明】
【図１】本発明の実施の形態におけるリニア振動モータとその駆動制御装置を含む全体構成図である。
【図２】図１に示す駆動制御装置の詳細を示すブロック図である。
【図３】リニア振動モータにおける駆動制御方法の全体的な処理の概略を示すフローチャートである。
【図４】図３のフローチャートに基づく駆動制御処理対象となる信号の経時変化を示すタイミングチャートである。
【図５】リニア振動モータの駆動制御処理を間断なく行うためのタイミング設定用に使用される３つのタイマ１、２、３の動作関係の説明図である。
【図６】リニア振動モータの駆動制御のための各処理１，２，３を同時並列的に行うための各タイマ１、２、３との相互の関係を示す説明図である。
【図７】図５および図６で示す各タイマ１、２、３の動作をより詳細に表したタイミングチャートである。
【図８】図３に示したリニア振動モータの駆動制御動作をより詳細に表したフローチャートであり、タイマ１に着目したときのタイミング動作を示す。
【図９】図３に示したリニア振動モータの駆動制御動作をより詳細に表したフローチャートであり、タイマ２に着目したときのタイミング動作を示す。
【図１０】図３に示したリニア振動モータの駆動制御動作をより詳細に表したフローチャートであり、タイマ３に着目したときのタイミング動作を示す。
【図１１】誘起電圧演算部におけるノイズ除去処理の手順を示すフローチャートである。
【図１２】動作状態検出部で近似関数に基づいて振動子の位置情報と速度情報を得るための処理内容の一例を示すフローチャートである。
【図１３】動作状態検出部で近似関数に基づいて振動子の位置情報と速度情報を得るための他の処理内容の一例を示すフローチャートである。
【図１４】動作状態検出部で近似関数に基づいて振動子の位置情報と速度情報を得るための他の処理内容の一例を示すフローチャートである。
【図１５】動作状態検出部で近似関数に基づいて振動子の位置情報と速度情報を得るための他の処理内容の一例を示すフローチャートである。
【図１６】従来のリニア振動モータの駆動制御を説明するタイミングチャートである。
【符号の説明】
１　　リニア振動モータ
２　　駆動制御装置
５　　固定子
５ａ　巻線
６　　振動子
１０　　電流検出部
１１　　電圧検出部
１３　　制御回路部
１４　　制御出力部
２１　　誘起電圧演算部
２２　　近似関数演算部
２３　　動作状態検出部
２４　　制御演算部
２５　　全体制御部
Ｚ１，Ｚ２，Ｚ３　　タイマ１，２，３[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drive control method and a drive control device for a linear vibration motor that causes a vibrator to reciprocate linearly with respect to a stator.
[0002]
[Prior art]
In general, a linear vibration motor has, for example, a stator having an electromagnet and a vibrator having a permanent magnet, and controls a drive current supplied to windings forming the electromagnet to control the stator. To reciprocate the vibrator.
[0003]
Here, for example, when a linear vibration motor is applied to an electric razor or the like, if the speed at which the vibrator reciprocates changes depending on the size of the load, the sharpness of the razor also changes. Therefore, in order to reduce such inconveniences, it is important to control the vibrator to always maintain a constant speed regardless of the magnitude of the load. In other words, in reciprocating the vibrator with respect to the stator, the driving direction of the vibrator and the driving direction with respect to the vibrator are driven in synchronization with each other, and the size of the external load applied to the linear vibration motor is reduced. Regardless, it is necessary to control the drive current to the winding according to the size of the load so that the vibrator always has a constant speed.
[0004]
Therefore, the conventional linear vibration motor is provided with sensors for detecting the position and speed of the vibrator, respectively, and synchronizes the operation direction of the vibrator and the driving direction with respect to the vibrator based on the position information detected by the position sensor. Based on the speed information detected by the speed sensor, a PWM control (a control in which the drive frequency is constant and the duty ratio is changed) that varies the pulse width of the drive current for exciting the winding is performed, so that the speed of the vibrator depends on the load. And always keep it constant. However, if a sensor for detecting the movement of the vibrator is separately provided as described above, the cost is increased, and it is difficult to cope with miniaturization in order to secure a space for mounting the sensor.
[0005]
Therefore, in the related art, an induced voltage is generated in the winding of the stator in accordance with the reciprocating operation of the vibrator. Therefore, a voltage detecting unit for detecting the magnitude of the induced voltage is provided, and a detection output of the voltage detecting unit is provided. A technique has been proposed in which the position and the speed of the vibrator are determined based on each of them (for example, see JP-A-2001-16892). In other words, this means that a sinusoidal induced voltage is generated in the winding of the stator, which is the drive unit of the linear vibration motor, in accordance with the reciprocating motion of the vibrator. It focuses on the phenomenon that the value of the induced voltage is the same as the vibration frequency of the vibrator, and the value of the induced voltage increases as the moving speed of the vibrator increases.
[0006]
Specifically, as shown in FIG. 16, the velocity of the vibrator is zero, that is, the vibration direction is the position of the zero cross point where the magnitude of the sinusoidal induced voltage becomes zero (the position indicated by the symbol p in FIG. 16). It is determined that this is a turning point at which switching is performed. When the speed of the vibrator is high, the magnitude of the induced voltage increases accordingly (curve S1 in FIG. 16A), and when the speed of the vibrator is low, the magnitude of the induced voltage decreases accordingly. (Curve S2 in FIG. 16A), for example, a differential value (gradient of the curve) of the induced voltage at the zero cross point p is obtained, and the speed of the vibrator is determined based on the magnitude of the differential value.
[0007]
Then, as shown in FIG. 16B, the signal generation timing when the drive current for exciting the stator winding is PWM-controlled is determined by the position of the zero cross point p, and the induced voltage of the zero cross point p is determined. By changing the pulse width W in the case where the drive current is subjected to the PWM control according to the magnitude of the gradient, the speed of the vibrator is always constant regardless of the load.
[0008]
[Problems to be solved by the invention]
As described above, in the case where the magnitude of the induced voltage generated in the winding of the stator due to the reciprocating operation of the vibrator is detected, it is not necessary to provide a separate sensor. However, the following problems remain.
[0009]
That is, the winding of the electromagnet included in the stator is originally supplied with a drive current for excitation. Therefore, not only the induced voltage due to the reciprocating operation of the vibrator but also the drive current of the drive current is supplied to the winding. An applied voltage at the time of supply is also generated. Therefore, simply detecting the voltage generated in the winding simply superimposes the applied voltage generated when the drive current is supplied and the induced voltage generated in the winding due to the reciprocating operation of the vibrator. It is difficult to detect with high accuracy. Therefore, conventionally, off-periods T1 and T2 of a predetermined width in which the excitation drive current does not flow through the stator winding are secured at positions before and after including the zero-cross point of the induced voltage waveform. Only by detecting the induced voltage of the winding, the induced voltage is prevented from including an extra error component, and the detection accuracy is increased.
[0010]
However, when the off periods T1 and T2 are provided, as shown in FIG. 16C, the maximum pulse width Wmax when the drive current is PWM-controlled by the off periods T1 and T2 is increased. Be regulated. In other words, since the time for energizing the stator windings can be limited, it is not possible to cope with the necessity of flowing an even larger energizing current through the windings due to a large external load, and the performance of the linear vibration motor is maximized. Can not be demonstrated.
[0011]
The present invention has been made in view of the above circumstances, and the position information and the speed information of the vibrator can be obtained without providing an off period in which the excitation drive current does not flow through the stator winding as in the related art. It is an object of the present invention to provide a drive control method of a linear vibration motor and a drive control device therefor, which can be obtained with high accuracy and can perform drive control more efficiently.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is as follows.
That is, a drive control method for a linear vibration motor according to the present invention includes a stator and a vibrator that reciprocates with respect to the stator, at least one of which includes an electromagnet, and a winding of the electromagnet. A drive control method for a linear vibration motor for supplying a drive current to a wire and vibrating a vibrator linearly with respect to a stator, wherein both a current flowing through a winding of the electromagnet and a voltage generated in the winding are combined. Based on the detected current value and voltage value, the induced voltage generated by the vibration of the vibrator is sequentially calculated based on a predetermined arithmetic expression. Obtaining an approximate function obtained by smoothing the calculated value, obtaining position information and speed information of the vibrator from the approximate function, and controlling a drive current supplied to the winding of the electromagnet based on the information. It is characterized.
[0013]
Thus, even if the voltage detected at the winding of the electromagnet is a superposition of the applied voltage generated by the supply of the driving current and the induced voltage generated at the winding due to the reciprocating operation of the vibrator, the voltage is induced by the arithmetic expression. By calculating the voltage, the effect of the applied voltage can be substantially eliminated. For this reason, it is possible to reliably detect the induced voltage generated in the winding even while the drive current is flowing through the winding. Furthermore, since an approximate function obtained by smoothing the induced voltage calculation value is obtained, a continuous induced voltage can be calculated even from data obtained at a coarse sampling period. Therefore, there is no need to provide an off-period in which no excitation drive current flows through the stator winding as in the related art, so that more efficient drive control can be performed.
[0014]
A drive control method for a linear vibration motor according to a second aspect of the present invention is the drive control method according to the first aspect, further comprising: processing 1 for detecting the current and voltage to calculate an induced voltage; And a process 3 for controlling the driving current of the winding based on the position information and the speed information of the vibrator by obtaining a position information and a speed information of the vibrator. It is characterized in that it is performed simultaneously and in parallel.
[0015]
As a result, since the processing 1 to the processing 3 are executed without interruption, the time required from the detection of the current and the voltage of the winding to the control of the driving current of the vibrator can be shortened as a whole. Higher speed can be achieved.
[0016]
According to a third aspect of the present invention, in the drive control method for a linear vibration motor according to the first or second aspect, a least squares method is used for obtaining an approximate function obtained by smoothing each of the induced voltage calculation values. It is characterized by approximation using the cubic function.
[0017]
Thereby, the load of the calculation process is smaller than when the approximate function of the induced voltage is obtained by using the trigonometric function, and approximation is possible even when the load of the vibrator during the reciprocation is asymmetric.
[0018]
According to a fourth aspect of the present invention, in the drive control method for a linear vibration motor according to any one of the first to third aspects, a sampling interval for detecting the current and the voltage within one reciprocating period of the vibrator is provided. And the sampling number is fixed so as to be constant. This makes it possible to make a constant in the calculation processing for obtaining the approximate function, thereby facilitating calculation.
[0019]
According to a fifth aspect of the present invention, in the drive control method for a linear vibration motor according to any one of the first to fourth aspects, sampling is performed during a period in which no drive current is supplied to the winding of the electromagnet. If the current value obtained through the obtained winding is equal to or less than a predetermined threshold value, the current value is fixed to zero regardless of the sampled current value until the next drive current is supplied. I have. Thereby, the noise resistance in the current detection is improved, and the accuracy in calculating the induced voltage calculation value is also improved.
[0020]
According to a sixth aspect of the present invention, in the drive control method for a linear vibration motor according to any one of the first to fifth aspects, the sampling is performed within a period in which a drive current is supplied to the winding of the electromagnet. When the absolute value of the current obtained by the sampling is smaller than the absolute value of the current obtained by the previous sampling, the current value obtained by the previous sampling is adopted. Thereby, the noise resistance in the current detection is further improved, and the accuracy in calculating the induced voltage calculation value is also improved.
[0021]
According to a seventh aspect of the present invention, in the drive control method for a linear vibration motor according to any one of the first to sixth aspects, a voltage value obtained by sampling a voltage generated in the winding is a predetermined value. When the value is equal to or higher than the threshold value, the calculation of the induced voltage is not performed, and the induced voltage value estimated from the value of the induced voltage calculated at the time of sampling before the sampling is adopted. This further promotes smoothing when obtaining the approximate function from the induced voltage calculation value, and improves the accuracy when obtaining the approximate function.
[0022]
A drive control method for a linear vibration motor according to an eighth aspect of the present invention is the drive control method according to any one of the first to seventh aspects, wherein a calculation range for obtaining an approximate function from the induced voltage calculation value is limited. It is characterized in that a zero-crossing point at which the value of the approximation function is inverted between positive and negative is obtained within the limited calculation range, and this zero-crossing point is obtained as position information of the transducer. Thus, the number of calculations for obtaining the position information of the transducer is reduced, and the calculation load can be reduced.
[0023]
According to a ninth aspect of the present invention, in the drive control method for a linear vibration motor according to any one of the first to eighth aspects, a maximum value of values within one cycle of the approximation function is set to the vibrator. It is obtained as speed information. Thus, only one peak search of the approximate function needs to be performed, so that speed information can be easily obtained.
[0024]
According to a tenth aspect of the present invention, in the drive control method for a linear vibration motor according to any one of the first to eighth aspects, a maximum value and a minimum value of values within one cycle of the approximation function are provided. Is obtained as speed information of the transducer. Thus, when the vibrator vibrates, the speed information can be accurately detected even when the amplitude is deviated to one side.
[0025]
According to an eleventh aspect of the present invention, in the drive control method for a linear vibration motor according to any one of the first to eighth aspects, a differential value at a zero-cross point where the value of the approximation function is inverted between positive and negative is determined by the oscillator. It is obtained as speed information. Thereby, the speed detection accuracy of the vibrator is increased, and the calculation can be easily performed.
[0026]
According to a twelfth aspect of the present invention, in the drive control method for a linear vibration motor according to any one of the first to eighth aspects, the approximation function is linearly changed near a zero crossing point where the value of the approximation function is inverted. It is characterized in that approximation and the inclination of the approximation line are obtained as speed information of the vibrator. Thus, even when a calculation error occurs when obtaining the value of the approximation function, the effect of the calculation error can be reduced by performing the linear approximation, and the speed can be detected more accurately.
[0027]
A drive control method for a linear vibration motor according to a thirteenth aspect of the present invention is the drive control method for a linear vibration motor according to any one of the first to eighth aspects, wherein the induced voltage calculation value is calculated over a period corresponding to one reciprocation period of the vibrator. Are sequentially added, and the added value is obtained as speed information of the vibrator. This is equivalent to finding the area of one cycle of the sinusoidal induced voltage, but this area calculation only needs to sequentially add the values of the induced voltage operation values, and there is no need to find the peak position of the approximate function. Therefore, the calculation time can be shortened.
[0028]
A drive control device for a linear vibration motor according to a fourteenth aspect of the present invention has a stator and a vibrator, at least one of which includes an electromagnet, and supplies a drive current to a winding of the electromagnet. A vibrator that vibrates linearly with respect to the stator, a current detecting unit that detects a current flowing through the winding of the electromagnet, a voltage detecting unit that detects a voltage generated in the winding of the electromagnet, An induced voltage calculation unit that calculates an induced voltage generated by the vibration of the vibrator from the current value and the voltage value detected by the unit based on a predetermined calculation expression; and an induced voltage calculation value obtained by the induced voltage calculation unit. An approximation function operation unit that obtains an approximate function obtained by smoothing each induced voltage operation value from the above; an operation state detection unit that obtains position information and velocity information of the vibrator from the approximation function obtained by the approximation function operation unit; State detection The in drive current to the windings based on the position information and speed information of the detected oscillator is characterized in that it comprises a control arithmetic unit for PWM control, a.
[0029]
As a result, similarly to the case of the first aspect of the invention, the induced voltage generated in the winding can be reliably detected even during the period in which the drive current is flowing through the winding. There is no need to provide an off-period in which no excitation drive current flows through the winding, and more efficient drive control becomes possible.
[0030]
According to a drive control device for a linear vibration motor according to a fifteenth aspect of the present invention, in the configuration of the fourteenth aspect, a current and a voltage are detected by the current detection unit and the voltage detection unit, and induced by the induced voltage calculation unit. A process 1 for calculating a voltage, a process 2 for calculating an approximation function by the approximation function calculation unit and obtaining position information and speed information of the vibrator by the operation state detection unit, and a drive current by the control calculation unit. It is characterized by including timer means for setting timing for performing the controlling process 3 in parallel during one reciprocating period of the vibrator.
[0031]
As a result, similarly to the second aspect of the invention, since the processing 1 to the processing 3 are executed without interruption, the time required from the detection of the current and the voltage of the winding to the control of the driving current of the vibrator is reduced as a whole. Therefore, the drive control process can be speeded up.
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an overall configuration diagram including a linear vibration motor and its drive control device, and FIG. 2 is a block diagram showing details of the drive control device.
[0033]
In this embodiment, a linear vibration motor 1 includes a stator 5 composed of an electromagnet having a winding 5a, a vibrator 6 having a permanent magnet, a frame 7 holding the vibrator 6, and a vibrator 6 and a frame. 7 has a spring 8 suspended therebetween, and supplies a driving current to a winding 5a of an electromagnet constituting the stator 5, thereby causing the vibrator 6 to reciprocate linearly with respect to the stator 5. It is made to let.
[0034]
The drive control device 2 performs PWM control of a drive current supplied to the winding 5a of the stator 5 according to the position and speed of the vibrator 6, and includes a current detection unit 11 that detects a current flowing through the winding 5a, A voltage detector 12 for detecting the voltage generated on the line 5a, and information on the position and speed of the vibrator 6 are obtained based on the current and voltage detected by the two detectors 11 and 12, and winding is performed based on both information. A control circuit unit 13 for determining a signal output timing and a pulse width for PWM control of the drive current to the line 5a, and a drive current PWM-controlled based on the output from the control circuit unit 13 And a control output 14 for supplying to line 5a.
[0035]
As shown in FIG. 2, the control circuit unit 13 calculates an induced voltage generated due to the vibration of the vibrator 6 from a current value and a voltage value detected by the two detection units 11 and 12 according to a predetermined arithmetic expression (( An induced voltage calculation unit 21 that calculates based on Expression 1)), and a cubic function p (x) using a least squares method to smooth each induced voltage calculation value y obtained by the induced voltage calculation unit 21 (Approximate function calculating unit 22 approximated by (formula 2) described later) and an operation state detecting unit that obtains position information and velocity information of the vibrator 6 from the approximate function p (x) obtained by the approximate function calculating unit 22 23, and information for determining a signal output timing and a pulse width for PWM control of a drive current to the winding 5a based on the position information and the speed information of the vibrator 6 detected by the operation state detection unit 23. The control operation unit 24 and these units 21 to 21 And a general control section 25 that controls the 4.
[0036]
In the overall control unit 25, three timers 1, a timer 2, and a timer 3 (indicated by reference numerals Z1 to Z3) are provided as timer means. These timers 1 to 3 (Z1 to Z3) are provided within one reciprocating period of the vibrator 6 so that the processes of the units 21 to 24 constituting the circuit control unit 13 are executed without interruption. The timing for executing the processing in parallel is set, and the operation of each of the timers 1 to 3 will be described in further detail later.
[0037]
Next, a drive control method in the linear vibration motor 1 having the above configuration will be described first with reference to the flowchart of FIG. 3 and the timing chart of FIG. The symbol S means a step.
[0038]
When a drive current (see FIG. 4A) for excitation is supplied to the winding 5a of the stator 5 from the drive control device 2 for excitation, the vibrator 6 is driven accordingly (see FIG. b)), an applied voltage is generated in the winding 5a, and an induced voltage is generated as the vibrator 6 reciprocates. Then, a current flowing through the winding 5a of the stator 5 (see FIG. 4D) and a voltage generated in the winding 5a (see FIG. 4C) are detected by the current detecting unit 11 and the voltage detecting unit 12, respectively. (S01).
[0039]
The detected current value and voltage value are sent to the control circuit unit 13. The induced voltage calculation unit 21 of the control circuit unit 13 samples the current value and the voltage value detected by the detection units 11 and 12 to remove noise components included in the current value and the voltage value, and performs sampling. From the current value and the voltage value, an induced voltage y (see FIG. 4 (e)) generated by the vibration of the vibrator 6 is sequentially calculated based on a predetermined calculation expression shown in (Equation 1) (S02).
[0040]
(Equation 1)

[0041]
The details of the noise removal processing will be described later. If the sampling interval and the number of samplings for detecting the current and the voltage during one round-trip period of the vibrator 6 are fixed in advance so as to be constant, an approximate function is obtained based on (Equation 2) described later. In this case, a constant can be obtained in the operation processing, so that the operation is facilitated.
[0042]
Since the induced voltage calculation value obtained based on the above (Equation 1) does not have a smooth curve and has severe irregularities, it is possible to determine the maximum value, the minimum value, and the zero cross point of the sinusoidal induced voltage as it is. difficult. Therefore, each induced voltage operation value y obtained by (Equation 1) is sent to the approximation function operation unit 22 in the next stage. The approximation function operation unit 22 converts the approximation function p (x) (see FIG. 4F) obtained by approximating each induction voltage operation value y using the least squares method in order to smooth the induction voltage operation value y. It is determined based on equation (2) (S03). That is, since (Equation 2) in this case is a cubic function p (x), the coefficients b0 to b3 that define the cubic function p (x) are obtained. As described above, by calculating the approximate function p (x), the induced voltage estimation value y is smoothed, so that it is easy to determine the maximum value, the minimum value, and the zero cross point of the induced voltage.
[0043]
[Equation 2]

[0044]
Although a trigonometric function can be applied as the approximation function p (x), it is possible to reduce the burden of the calculation process by obtaining the cubic function p (x) as the approximation function as in this embodiment. Further, even when the load applied during the reciprocating operation of the vibrator 6 is asymmetric, approximation is possible, which is advantageous.
[0045]
Subsequently, the data of each of the coefficients b0 to b3 of the approximation function p (x) is sent to the operation state detection unit 23, so that the operation state detection unit 23 calculates the approximation function p (x) The position information and the speed information of the vibrator 6 are obtained (S04). For example, a zero cross point at which the value of the approximation function p (x) reverses the sign is determined, and this zero cross point is determined as a turning point at which the vibration direction of the vibrator 6 switches, and its position information is obtained. Further, the maximum value of the values within one cycle of the approximation function p (x) is determined as the maximum speed of the vibrator 6, and the speed information is obtained.
[0046]
Thus, the position information and speed information of the vibrator 6 detected by the operation state detection unit 23 are sent to the control calculation unit 24. The control operation unit 24 determines a signal output timing and a pulse width for performing PWM control of the drive current to the winding 5a of the stator 5 based on the information, and outputs the information to the drive output unit 14 ( S05). The drive output unit 14 supplies a drive current PWM-controlled to the winding 5 a of the stator 5 based on information from the control circuit unit 13. As a result, the vibrator 6 is driven and controlled so that the operation direction and the drive direction are synchronized and the speed is always kept constant regardless of the magnitude of the external load.
[0047]
Here, as shown in FIG. 3, the current detection unit 11 and the voltage detection unit 12 detect the current and the voltage, and the induced voltage calculation unit 21 calculates the induced voltage until the induced voltage calculation value y is obtained. The processing (S01 and S02) is referred to as processing 1, and the processing until the approximate function p (x) is calculated by the approximate function calculation unit 22 and the position information and the speed information of the vibrator 6 are obtained by the operation state detection unit 23 (S03 and S02). S04) is defined as processing 2, and the processing (S05) of performing PWM control of the drive current by the control calculation unit 24 is defined as processing 3. In addition, when the three reciprocating periods of the vibrator 6 are regarded as one cycle, each reciprocating period is distinguished from Ts1, Ts2, and Ts3.
[0048]
At this time, the induced voltage calculation unit 21 performs the process 1 in the period Ts1, the process 2 is performed in the approximate function calculation unit 22 and the operation state detection unit 23 in the next period Ts2, and the control calculation is performed in the next period Ts3. If the sequence is such that the unit 24 executes the process 3, the other processes are stopped during the execution of one process, so that the PWM control is appropriately performed only every three reciprocating periods (= Ts1 + Ts2 + Ts3) of the vibrator 6. It cannot output the driven signal. In other words, the drive control of the vibrator 6 takes too much time, and the speed of the drive control process cannot be increased.
[0049]
On the other hand, as shown in FIG. 5, in each of the periods Ts1, Ts2, and Ts3, if the processes 1, 2, and 3 are performed simultaneously and in parallel, the one round trip period Ts1 and Ts2 of the vibrator 6 can be achieved. , Ts3, a drive signal appropriately PWM-controlled can be output. However, if the result of the processing 1 cannot be obtained, the processing 2 cannot be executed, and if the result of the processing 2 cannot be obtained, the processing 3 cannot be executed. Therefore, a memory (not shown) for storing the processing results is stored in each of the units 21 to 24. For example, when the induced voltage calculation unit 21 performs the process 1 in the period Ts3, the approximate function calculation unit 22 and the operation state detection unit 23 are obtained in the period Ts2 one period before. It is necessary to execute the process 2 based on the result of the process 1 and to allow the control operation unit 24 to execute the process 3 based on the result of the process 1 obtained in the period Ts1 two periods before. As described above, in order to perform the processes 1, 2, and 3 simultaneously and in parallel for each one reciprocation period Ts1, Ts2, Ts3,... Of the vibrator 6, it is necessary to set the switching timing of each of the processes 1 to 3. . Therefore, the overall control unit 25 is provided with three timers 1 to 3 (Z1 to Z3) interlocked with each other as shown in FIG.
[0050]
That is, as shown in FIG. 6, the timer 1 (Z1) starts counting time in response to the trigger signal from the timer 2 (Z2), and outputs a trigger signal for starting the execution of the processing 1, and the period Ts1 is shorter. When the time elapses, a trigger signal for starting the execution of the processing 2 is output, and when the time period Ts2 elapses, a trigger signal for starting the execution of the processing 3 is output, and a trigger signal for starting the time measurement is output to the timer 3 (Z3). The timer 3 (Z3) starts timing in response to a trigger signal from the timer 1 (Z1), and outputs a trigger signal for starting the execution of the processing 1, and when the period Ts3 has elapsed, a trigger for starting the execution of the processing 2 is output. A signal is output, and when the period Ts1 has elapsed, a trigger signal for starting execution of the process 3 is output, and a trigger signal for starting time measurement is output to the timer 2 (Z2). In addition, the timer 2 (Z2) starts timing in response to the trigger signal from the timer 3 (Z3), and outputs a trigger signal for starting the execution of the process 1, and when the period Ts2 elapses, the process 2 starts. An execution start trigger signal is output, and when the period Ts3 has elapsed, a trigger signal for starting execution of the process 3 is output, and a timer start trigger signal is output to the timer 1 (Z1).
[0051]
Thereby, as shown in FIG. 6, in each of the periods Ts1, Ts2, and Ts3, the processes 1, 2, and 3 are performed simultaneously and in parallel, and the processes 1 to 3 are executed without interruption. For this reason, the time required from the detection of the current and voltage of the winding 5a of the stator 5 to the control of the drive current of the vibrator 6 can be shortened as a whole, and the drive control processing can be speeded up. .
[0052]
FIG. 7 is a timing chart showing the operation of each of the timers 1 to 3 described in FIGS. 5 and 6 in more detail. FIGS. 8 to 10 show the drive control operation of the linear vibration motor shown in FIG. FIG. 8 is a flowchart showing the timer 1 (Z1), FIG. 9 shows the timer 2 (Z2), and FIG. 10 shows the timer 3 (Z3). , Respectively.
[0053]
Here, for example, focusing on timer 1 (Z1), in FIG. 8, steps 1, 2, and 9 correspond to processing 1 in FIG. 3, step 3 corresponds to processing 2 in FIG. Corresponds to the process 3 in FIG. Then, the counter value is cleared by the trigger signal from the timer 2 (Z2), and time counting is started. After that, when the processing 1 ends at the time t1-2, the processing 2 is executed until the time t1-3, At time t1-3, a trigger signal is output to timer 3 (Z3), and process 3 is executed during a period from time t1-4 to time t1-7. 9 and FIG. 10 are the same as the processing in the case of FIG. 8, and the detailed description is omitted here.
[0054]
FIG. 11 shows a specific example for removing a noise component included when the induced voltage calculation unit 21 samples the current value and the voltage value detected by the detection units 11 and 12 in the process 1 (S02) of FIG. 9 is a flowchart showing the details of processing. The induced voltage calculation unit 21 first samples the current value and the voltage value detected by the current detection unit 11 and the voltage detection unit 12, respectively (S1, S2). It is determined whether or not the driving current is supplied to the line 5a during the periods Th and Tl (see FIG. 4A) (S3).
[0055]
If the drive current is not supplied to the winding 5a, it is determined whether or not the absolute value of the value of the current flowing through the winding 5a obtained by sampling is equal to or less than a predetermined threshold value Ih. (S4). If the absolute value of the sampled current value is equal to or smaller than the predetermined threshold value Ih, the current value is forcibly fixed to zero until the next drive current is supplied (S6). If the absolute value of the sampled current value is larger than the predetermined threshold value Ih in S4, it is determined whether or not the current value obtained by the previous sampling is zero (S5). . When the current value obtained by the previous sampling is zero, the current value obtained by the current sampling is also likely to be noise. In this case, the process proceeds to S6 to forcibly reduce the current value. Fixed to zero. On the other hand, if the current value obtained in the previous sampling is not zero in S5, the current value obtained in the current sampling can be regarded as not noise, and the process proceeds to S7.
[0056]
In S3, when the timing at which the current value is sampled is within Th and Tl during the period in which the drive current is supplied to the winding 5a of the stator 5, the process proceeds to S7, and The absolute value is compared with the absolute value of the current obtained by the previous sampling.
[0057]
Here, if the absolute value of the current sampled this time is smaller than the absolute value of the current obtained by sampling the previous time, the detected current value is notwithstanding the drive current is being supplied. Is not simply increased or decreased and is considered abnormal. Therefore, the current value obtained by sampling the previous time is adopted (S8). On the other hand, when the absolute value of the current sampled this time is larger than the absolute value of the current obtained by previous sampling, the current value detected during the period in which the drive current is supplied is simply increased or Since it is considered that the current has simply decreased, the current sampled this time is used as it is. Thereby, noise resistance in current detection is improved, and accuracy in calculating the induced voltage calculation value y is also improved.
[0058]
Subsequently, the induced voltage calculation unit 21 compares the absolute value of the difference between the induced voltage detected by the current sampling and the induced voltage detected by the previous sampling with a preset threshold value Vh (S9).
[0059]
At this time, if the absolute value of the difference between the two induced voltages is equal to or smaller than the threshold value Vh, the value of the induced voltage sampled this time is used as it is to calculate the induced voltage based on (Equation 1) (S10). ). On the other hand, when the absolute value of the difference between the induced voltages sampled before and after is larger than the threshold value Vh, it is determined that the influence of noise is large, and the calculation of the induced voltage by (Equation 1) is not performed. Instead, an induced voltage value estimated from the value of the induced voltage calculated at the time of sampling before the current sampling is adopted (S11). The induced voltage estimated value in this case is calculated by, for example, obtaining an addition average or a geometric mean of the induced voltage calculated values obtained in the previous and previous and previous times, or replacing the calculated value with the previously obtained induced voltage calculated value. You. This further promotes smoothing when obtaining the approximate function from the induced voltage calculation value, and improves the accuracy when obtaining the approximate function.
[0060]
FIG. 12 shows a specific case where the operation state detection unit 23 obtains the position information and the velocity information of the vibrator 6 based on the approximate function p (x) of the equation (2) in the process 2 (S04) of FIG. It is a flowchart which shows a process content.
[0061]
Here, a zero-cross point at which the value of the approximation function p (x) is inverted is determined, and the zero-cross point is determined as a turning point at which the vibration direction of the vibrator 6 switches, thereby obtaining position information. In addition, the maximum value among the values within one cycle of the approximation function is determined as the maximum speed of the vibrator 6, and the speed information is obtained. With this configuration, only one peak search of the approximate function p (x) needs to be performed, so that the process for obtaining the speed information is facilitated.
[0062]
As described above, according to this embodiment, the voltage detected by voltage detector 12 is generated in winding 5a by the reciprocating operation of vibrator 6 and the applied voltage generated in winding 5a by the supply of the driving current. Even when the induced voltage is superimposed, the influence of the applied voltage can be substantially removed by calculating the induced voltage y using the operation formula shown in (Equation 1). Therefore, it is possible to reliably detect the induced voltage generated in the winding 5a even while the drive current is flowing through the winding 5a. Further, since the approximate function p (x) obtained by smoothing the induced voltage calculation value y is obtained, a continuous induced voltage can be calculated even from data obtained at a coarse sampling cycle. Therefore, the position and speed of the vibrator can be accurately detected.
[0063]
Therefore, there is no need to provide the off-periods T1 and T2 in which the excitation drive current does not flow through the winding 5a of the stator 5 as in the related art, so that more efficient drive control can be performed.
[0064]
In the above embodiment, as shown in FIG. 12, the maximum value within one cycle of the approximation function is obtained as the speed information of the vibrator 6, but as shown in the flowcharts of FIGS. It is also possible to obtain position information and speed information of the vibrator 6 by the processing.
[0065]
That is, in the processing of the flowchart shown in FIG. 13, the zero-cross point where the value of the approximation function p (x) reverses the sign is determined as the turning point where the vibration direction of the vibrator 6 switches, and the position information is obtained. Further, the difference between the maximum value and the minimum value within one cycle of the approximation function p (x) is obtained, and the difference is obtained as speed information of the vibrator 6. Thus, when the vibrator 6 vibrates, the speed information can be accurately detected even when the amplitude is offset to one side.
[0066]
In the process of the flowchart shown in FIG. 14, the range for calculating the induced voltage calculation value is limited, an approximate function is obtained only within the limited calculation range, and the sampling time of the smaller absolute value of the approximate function is approximated. The value of the function is determined as a zero-cross point where the sign is reversed, and this zero-cross point is determined as a turning point where the vibration direction of the vibrator 6 switches, and the position information is obtained.
[0067]
Further, the differential value at the zero cross point thus obtained is calculated, and this differential value is obtained as speed information of the vibrator 6. As described above, by limiting the range for calculating the induced voltage calculation value, the number of calculations for obtaining the position information of the vibrator 6 is reduced, which is advantageous because the calculation load can be reduced. In addition, when the differential value at the zero-cross point is obtained as the speed information of the vibrator 6, the speed detection accuracy of the vibrator 6 increases, and the calculation can be easily performed.
[0068]
Instead of obtaining the differential value at the zero cross point as velocity information of the vibrator 6, for example, a linear approximation of the approximate function is performed near the zero cross point at which the value of the approximate function reverses positive and negative, and the slope of the approximate straight line is calculated by It can also be obtained as speed information. In this case, even if a calculation error occurs when the value of the approximation function is obtained, the effect of the calculation error is reduced by performing the linear approximation, so that the speed can be detected more accurately.
[0069]
In the process of the flowchart shown in FIG. 15, the zero-cross point at which the value of the approximation function p (x) reverses the sign is determined as a turning point at which the vibration direction of the vibrator 6 switches, and the position information is obtained. Further, the values of the induced voltage calculation values are sequentially added over a period corresponding to one reciprocation period of the vibrator 6, and the added value is obtained as speed information of the vibrator 6. This is equivalent to finding the area of one cycle of the sinusoidal induced voltage, but this area calculation only needs to sequentially add the values of the induced voltage operation values, and there is no need to find the peak position of the approximate function. Therefore, the calculation time can be shortened.
[0070]
Furthermore, the present invention is not limited to the methods and configurations described in the above embodiments, and can be appropriately modified without departing from the spirit of the present invention.
[0071]
【The invention's effect】
According to the drive control method of the linear vibration motor according to the first aspect of the present invention, the voltage generated in the winding is the applied voltage generated by the supply of the driving current and the induced voltage generated in the winding due to the reciprocating operation of the vibrator. Even if they are superimposed on each other, the effect of the applied voltage can be substantially removed by calculating the induced voltage using the calculation formula. This makes it possible to reliably detect the induced voltage generated in the winding even while the drive current is flowing through the winding. Then, since an approximate function obtained by smoothing the induced voltage calculation value is obtained, a continuous induced voltage can be calculated even from data obtained at a coarse sampling period. Thereby, the position information and the speed information of the vibrator can be accurately obtained from the approximate function. Therefore, there is no need to provide an off period during which no excitation drive current flows through the stator winding as in the related art, and more efficient drive control becomes possible.
[0072]
According to the drive control method for a linear vibration motor according to the second aspect of the present invention, in addition to the effects of the first aspect, a process 1 for detecting the current and voltage to calculate an induced voltage; A process 2 for obtaining an approximate function from a voltage calculation value to obtain position information and speed information of the vibrator, and a process 3 for controlling a drive current of the winding based on the position information and speed information of the vibrator, Since the processing is performed simultaneously and in parallel within one reciprocating period of the vibrator, the above processing 1 to processing 3 are executed without interruption. As a result, the time required from the detection of the current and voltage of the winding to the control of the drive current of the vibrator can be shortened as a whole, and the drive control process can be sped up.
[0073]
A drive control method for a linear vibration motor according to a third aspect of the present invention provides, in addition to the effects of the first or second aspect, a third-order method using a least squares method when smoothing an induced voltage calculation value. Since the approximation is performed by a function, the load of the calculation process is smaller than when the trigonometric function is used as the approximation function, and the approximation is possible even when the load of the vibrator during reciprocation is asymmetric.
[0074]
A drive control method for a linear vibration motor according to a fourth aspect of the present invention, in addition to the effect of the first aspect, detects the current and the voltage within one reciprocating period of the vibrator. Since the sampling interval and the number of samplings in the case are fixed so as to be always constant, it is possible to make constants in the calculation processing for obtaining the approximate function, and the calculation processing is further facilitated.
[0075]
A drive control method for a linear vibration motor according to a fifth aspect of the present invention provides, in addition to the effects of the first aspect, a period in which no drive current is supplied to the windings of the electromagnet. , Contains noise, the noise is forcibly reduced to zero, so that the noise resistance in current detection is improved and the accuracy in calculating the induced voltage calculation value is improved.
[0076]
A drive control method for a linear vibration motor according to a sixth aspect of the present invention provides, in addition to the effects of the first aspect, a period in which a drive current is supplied to the windings of the electromagnet. If the current value sampled within is equal to or greater than the threshold value, it is regarded as noise and replaced with data sampled before that, so that the noise resistance in current detection is further improved, and the The accuracy is improved.
[0077]
A drive control method for a linear vibration motor according to a seventh aspect of the present invention provides, in addition to the effects of the first aspect, a voltage value obtained by sampling a voltage generated in the winding. If the value is equal to or higher than the predetermined threshold value, it is regarded as noise and calculation of the induced voltage is performed without estimating the current electromotive voltage value from the induced voltage calculation value calculated before the sampling without calculating the induced voltage. Smoothing in obtaining an approximation function from is further promoted, and accuracy in obtaining an approximation function is improved.
[0078]
According to the drive control method for a linear vibration motor according to the invention described in claim 8, in addition to the effect of the invention described in any one of claims 1 to 7, a calculation range when an approximate function is obtained from an induced voltage calculation value is limited. Then, the zero-cross point at which the value of the approximation function is inverted in the limited calculation range is obtained, so that the number of calculations for obtaining the position information of the vibrator is reduced, and the load of the calculation processing can be reduced. Processing can be speeded up.
[0079]
A drive control method for a linear vibration motor according to a ninth aspect of the present invention provides the drive control method for a linear vibration motor according to any one of the first to eighth aspects. Is obtained as the speed information of the transducer, the speed information can be easily obtained only by performing the peak search of the approximate function at only one place.
[0080]
A drive control method for a linear vibration motor according to a tenth aspect of the present invention provides, in addition to the effects of the first aspect, a maximum value of values within one cycle of the approximate function. And the minimum value is obtained as the speed information of the vibrator, so that when the vibrator vibrates, the speed information can be accurately detected even when the amplitude is offset to one side. .
[0081]
A drive control method for a linear vibration motor according to an eleventh aspect of the present invention provides, in addition to the effects of the invention according to any one of the first to eighth aspects, a differential value at a zero-cross point where the value of the approximation function reverses the sign. Is obtained as the speed information of the vibrator, the accuracy of detecting the speed of the vibrator is increased, and the calculation can be easily performed.
[0082]
A drive control method for a linear vibration motor according to a twelfth aspect of the present invention provides the drive control method for a linear vibration motor according to any one of the first to eighth aspects. The function is approximated by a straight line, and the slope of the approximated straight line is obtained as the speed information of the oscillator.Therefore, even if a calculation error occurs when calculating the value of the approximate function, the effect of the calculation error is reduced by performing the linear approximation. Thus, the speed can be detected with higher accuracy.
[0083]
A drive control method for a linear vibration motor according to a thirteenth aspect of the present invention provides the drive control method for a linear vibration motor according to any one of the first to eighth aspects, wherein the induction control is performed over a period corresponding to one reciprocation period of the vibrator. Since the area of one cycle of the sinusoidal induced voltage is obtained by sequentially adding the values of the voltage calculation values, and the value is obtained as the speed information of the vibrator, the processing for obtaining the speed information is simply an addition. Since the processing may be performed and the peak position of the approximate function need not be obtained, the calculation time can be shortened.
[0084]
A drive control device for a linear vibration motor according to a fourteenth aspect of the present invention ensures that an induced voltage generated in a winding during a period in which a drive current is flowing through the winding, as in the first aspect of the invention. Since the detection can be performed, it is not necessary to provide an off-period in which the excitation drive current does not flow through the stator winding as in the related art, so that more efficient drive control can be performed.
[0085]
A drive control device for a linear vibration motor according to a fifteenth aspect of the present invention includes, in addition to the effects of the fourteenth aspect, a timer means for regulating the execution timing of the first to third processes. Since the processes 1 to 3 are executed without interruption, the time required from the detection of the winding current and voltage to the control of the driving current of the vibrator can be shortened as a whole. In addition, the speed of the drive control process can be increased.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram including a linear vibration motor and a drive control device thereof according to an embodiment of the present invention.
FIG. 2 is a block diagram showing details of a drive control device shown in FIG. 1;
FIG. 3 is a flowchart showing an outline of an overall process of a drive control method in the linear vibration motor.
4 is a timing chart showing a temporal change of a signal to be subjected to drive control processing based on the flowchart of FIG. 3;
FIG. 5 is an explanatory diagram of an operation relationship of three timers 1, 2, and 3 used for timing setting for performing drive control processing of a linear vibration motor without interruption.
FIG. 6 is an explanatory diagram showing a mutual relationship with timers 1, 2, and 3 for simultaneously performing processes 1, 2, and 3 for drive control of a linear vibration motor in parallel.
FIG. 7 is a timing chart showing the operation of each of the timers 1, 2, and 3 shown in FIGS. 5 and 6 in more detail.
8 is a flowchart showing the drive control operation of the linear vibration motor shown in FIG. 3 in more detail, and shows a timing operation when attention is paid to the timer 1. FIG.
9 is a flowchart showing the drive control operation of the linear vibration motor shown in FIG. 3 in more detail, and shows a timing operation when focusing on the timer 2. FIG.
10 is a flowchart showing the drive control operation of the linear vibration motor shown in FIG. 3 in more detail, and shows a timing operation when attention is paid to a timer 3. FIG.
FIG. 11 is a flowchart illustrating a procedure of a noise removal process in an induced voltage calculation unit.
FIG. 12 is a flowchart illustrating an example of processing for obtaining position information and velocity information of a vibrator based on an approximation function in an operation state detection unit.
FIG. 13 is a flowchart illustrating an example of another processing content for obtaining position information and speed information of a vibrator based on an approximation function in an operation state detection unit.
FIG. 14 is a flowchart illustrating an example of another processing content for obtaining position information and speed information of a vibrator based on an approximation function in an operation state detection unit.
FIG. 15 is a flowchart illustrating an example of another processing content for obtaining position information and speed information of a vibrator based on an approximation function in an operation state detection unit.
FIG. 16 is a timing chart illustrating drive control of a conventional linear vibration motor.
[Explanation of symbols]
1 Linear vibration motor
2 Drive control device
5 Stator
5a winding
6 vibrator
10 Current detector
11 Voltage detector
13 Control circuit section
14 Control output section
21 Induced voltage calculator
22 Approximate function calculator
23 Operation state detector
24 control arithmetic unit
25 Overall control unit
Z1, Z2, Z3 Timers 1, 2, 3

Claims (15)

A linear vibration motor having a stator and a vibrator, at least one of which is formed of an electromagnet, supplies a drive current to the winding of the electromagnet and vibrates the vibrator linearly with respect to the stator. A drive control method,
A current flowing through the winding of the electromagnet and a voltage generated in the winding are both detected, and an induced voltage caused by the vibration of the vibrator is sequentially calculated from the detected current value and voltage value based on a predetermined calculation formula. Then, an approximate function obtained by smoothing each of the induced voltage arithmetic values is obtained from each of the induced voltage arithmetic values, position information and velocity information of the vibrator are obtained from the approximate function, and an electromagnet is generated based on the information. A drive control method for a linear vibration motor, comprising: controlling a drive current supplied to a winding of the linear vibration motor. A process 1 for detecting the current and the voltage to calculate the induced voltage, a process 2 for obtaining an approximate function from the calculated induced voltage and obtaining position information and speed information of the transducer, and position information of the transducer 2. The drive control method for a linear vibration motor according to claim 1, wherein the step of controlling the drive current of the winding based on the speed information is performed simultaneously and in parallel within one reciprocation period of the vibrator. The drive control method for a linear vibration motor according to claim 1, wherein, when obtaining an approximate function obtained by smoothing each of the induced voltage calculation values, the approximate function is approximated by a cubic function using a least squares method. 4. The linear vibration motor according to claim 1, wherein a sampling interval and a sampling number when detecting the current and the voltage within one reciprocation period of the vibrator are fixed. Drive control method. When the current value flowing through the winding obtained by sampling during the period in which the driving current is not supplied to the winding of the electromagnet is equal to or less than a predetermined threshold value, the next driving current is supplied. The drive control method for a linear vibration motor according to any one of claims 1 to 4, wherein the control is fixed to zero regardless of a sampled current value. If the absolute value of the current obtained by sampling during the period in which the drive current is supplied to the windings of the electromagnet is smaller than the absolute value of the current obtained by previous sampling, the previous sampling is performed. The drive control method for a linear vibration motor according to any one of claims 1 to 5, wherein a current value obtained by the above is adopted. If the voltage value obtained by sampling the voltage generated in the winding is equal to or greater than a predetermined threshold, the calculation of the induced voltage is not performed, and the calculation is performed based on the value of the induced voltage calculated at the time of sampling before the sampling. 7. The drive control method for a linear vibration motor according to claim 1, wherein the induced voltage value obtained is adopted. In addition to limiting the calculation range when obtaining an approximate function from the induced voltage calculation value, determine a zero-cross point at which the value of the approximate function reverses positive and negative within the limited calculation range. The drive control method for a linear vibration motor according to any one of claims 1 to 7, wherein the drive control method is obtained as: 9. The drive control method for a linear vibration motor according to claim 1, wherein a maximum value of values within one cycle of the approximation function is obtained as speed information of the vibrator. 9. The driving of the linear vibration motor according to claim 1, wherein a difference between a maximum value and a minimum value among values within one cycle of the approximation function is obtained as speed information of the vibrator. Control method. The drive control method for a linear vibration motor according to any one of claims 1 to 8, wherein a differential value at a zero cross point where the value of the approximation function is inverted is obtained as speed information of the vibrator. 9. The method according to claim 1, wherein the approximation function is linearly approximated near a zero crossing point at which the value of the approximation function is inverted, and a slope of the approximate line is obtained as speed information of the vibrator. Drive control method of linear vibration motor. 9. The method according to claim 1, wherein the values of the induced voltage calculation values are sequentially added over a period corresponding to one reciprocation period of the vibrator, and the added value is obtained as speed information of the vibrator. 4. A drive control method for a linear vibration motor according to claim 1. A linear vibration motor having a stator and a vibrator, at least one of which is formed of an electromagnet, supplies a drive current to the winding of the electromagnet and vibrates the vibrator linearly with respect to the stator. A drive control device,
A current detection unit that detects a current flowing through the winding of the electromagnet,
A voltage detection unit that detects a voltage generated in a winding of the electromagnet;
An induced voltage calculation unit that calculates an induced voltage generated due to the vibration of the vibrator from the current value and the voltage value detected by the two detection units based on a predetermined calculation expression;
An approximation function operation unit for obtaining an approximate function obtained by smoothing each induced voltage operation value from the induced voltage operation value obtained by the induced voltage operation unit;
An operation state detection unit that obtains position information and speed information of the transducer from the approximation function obtained by the approximation function calculation unit;
A control operation unit that controls a drive current to the winding based on the position information and speed information of the vibrator detected by the operation state detection unit;
A drive control device for a linear vibration motor, comprising: A process 1 in which a current and a voltage are detected by the current detection unit and the voltage detection unit, and an induced voltage is calculated by the induced voltage calculation unit; and an approximation function is calculated by the approximation function calculation unit, and the vibration is detected by the operation state detection unit. Timer for setting timing for performing, in parallel, processing 2 for obtaining position information and velocity information of the element and processing 3 for controlling the drive current by the control operation section within one reciprocating period of the vibrator. The drive control device according to claim 14, further comprising a unit.

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