JP4157316B2 - Circuit element driving device - Google Patents

Description

【００５４】
加算部１１、加算部１２および加算部１３は、それぞれ、電圧指令値ｕ₁、ｕ₂およびｕ₃を受け取り、共通指令値αと加算して、補正指令値ｒ₁、ｒ₂およびｒ₃を出力する。即ち、加算部１１、加算部１２および加算部１３は、（数４）によって算出される補正指令値ｒ_kを出力する。
【００５５】
【数４】

【００５６】
従来の回路素子駆動装置では、共通端子に電源電圧の中点の値に固定された電圧を印加していた。つまり、従来技術では、共通端子に印加される電圧は変化しない。これに対して、本発明の回路素子駆動装置では、共通端子５に変動する電圧を印加して、積極的に共通端子を駆動しており、共通端子５の制御方法にひとつの特徴がある。以上のように構成される回路素子駆動装置の動作を更に具体的に説明する。以下の例では、スピンドルモータ１のそれぞれのコイルを正弦波で駆動する場合を考える。
【００５７】
図２は、回路素子駆動装置の制御部７が受け取る第１の指令値および出力する第２の指令値を示している。図２において、横軸は時間の経過を示し、モータ駆動の１周期が１となるよう正規化されている。縦軸は電圧指令値ｕ_k、補正指令値ｒ_kおよび共通指令値αの大きさを示し、同様に正規化されている。電圧指令値ｕ₁は最大振幅０．５８の正弦波である。電圧指令値ｕ₂は電圧指令値ｕ₁に対して時間が１／３だけ後れた正弦波である。電圧指令値ｕ₃は電圧指令値ｕ₂に対して時間が１／３だけ後れた正弦波である。
【００５８】
図１に示すように、最大値計算部８、最小値計算部９は、電圧指令値ｕ₁、ｕ₂およびｕ₃を受け取り、最大値ｕ_maxおよび最小値ｕ_minを反転平均部１０へ出力する。反転平均部１０は（数３）で求められる共通指令値αを出力する。図２に示すように、共通指令値αは、電圧指令値ｕ_kの１／３の周期を持ち、最大振幅が０．１４の三角波となる。
【００５９】
加算部１１、１２および１３は共通指令値αと電圧指令値ｕ_kとを加算し、（数４）で求められる補正指令値ｒ_kを出力する。図２に示すように、補正指令値ｒ_kは正弦波の山部が変形した略台形波になる。補正指令値ｒ₁、ｒ₂およびｒ₃は互いに時間１／３だけずれており、振幅は±０．５以内である。
【００６０】
このように発生した共通指令値αならびに補正指令値ｒ₁、ｒ₂およびｒ₃は、図１に示す駆動部６へ入力され、これらの指令値に比例した駆動電圧である電圧Ｖ_com、Ｖ₁、Ｖ₂およびＶ₃が発生する。例えば、図２に示される指令値の５倍の値が電圧Ｖ_com、Ｖ₁、Ｖ₂およびＶ₃として駆動部６から出力される。
【００６１】
共通指令値αは、−０．１４から＋０．１４の範囲の値をとるため、電圧Ｖ_comは、−０．７Ｖから＋０．７Ｖの範囲の値をとる。また、補正指令値ｒ₁、ｒ₂およびｒ₃は−０．５Ｖから＋０．５Ｖの値をとるため、電圧Ｖ₁、Ｖ₂およびＶ₃は、−２．５Ｖから＋２．５Ｖの範囲の値をとる。これらの値はいずれも電源電圧の中点の値以下である。
【００６２】
図１に示すように、コイル２、３および４に印加される電圧は、それぞれ共通端子５と個別端子２ａとの電位差、共通端子５と個別端子３ａとの電位差および共通端子５と個別端子４ａとの電位差となる。コイル２、３および４に印加される電圧が最大となるのは、図２に示すように、共通指令値αが−０．１４となり、補正指令値ｒ₁が０．４４となるときである。このとき、電圧Ｖ_comおよびＶ₁は、−０．７Ｖおよび２．２Ｖとなり、コイル２には２．９Ｖの電圧が印加される。このため、時間の経過に伴って、コイル２には振幅２．９Ｖの正弦波が印加される。すなわち、コイル２に印加される最大電圧および最小電圧は、それぞれ＋２．９Ｖおよび−２．９Ｖである。コイル３および４の両端にも同様に−２．９Ｖから＋２．９Ｖの電圧が印加される。
【００６３】
共通端子５を電源電圧の中点に固定する従来の駆動では、従来技術として説明したように、最大電圧は２．５Ｖを印加するのが限界であったが、本発実施形態によれば、２．９Ｖの電圧を印加することが可能となり、印加できる電圧を１６％も増大させることができる。これは、図２に示すように、共通指令値αが一定の値をとるのではなく、変動しているからである。つまり、共通指令値αに基づく電圧Ｖ_comが変動する値であり、共通端子５には変動する電圧Ｖ_comが印加されるからである。個別端子２ａ、３ａおよび４ａに印加される電圧が、電源電圧の中点の値以上をとることができなくても、共通端子５に個別端子２ａとは逆の符号の電圧を印加することによって、回路素子であるコイル２、３、および４には、電源電圧の中点の値以上の電圧を印加することが可能となるのである。
【００６４】
つまり、コイル２、３、および４は、電圧指令値ｕ_kに基づいて変動する電圧Ｖ₁、Ｖ₂およびＶ₃と、電圧指令値ｕ_kに基づいて変動する電圧Ｖ_comを発生させ、電圧Ｖ_comをコイル２、３、および４の一端に共通に接続された共通端子５に印加し、電圧Ｖ₁、Ｖ₂およびＶ₃をコイル２、３、および４のそれぞれの他端である個別端子２ａ、３ａおよび４ａに印加することによって駆動している。このように各コイルの一端を共通端子５に共通に接続することによって３つのコイルと接続すべき端子や配線の数を少なくすることができる。また、上述したように、共通端子５へ印加する電圧も変動させて、コイル２、３、および４を駆動するので、各コイルに印加する電圧の最大値が小さくなってしまうことを防止できる。
【００６５】
本実施形態において、電圧指令値ｕ₁、ｕ₂およびｕ₃の位相は、１／３周期ずつずれていたが、電圧指令値ｕ₁、ｕ₂およびｕ₃の位相が同相である場合、各コイルに印加できる最大電圧を５Ｖにすることもできる。
【００６６】
また、スピンドルモータのコイルを駆動する場合のように、回路素子を駆動する指令値の波形が周期的である場合、共通指令値αの波形も周期的になる。また、共通指令値αは電圧指令値ｕ_kの振幅に比例する。従って、１周期分の共通指令値αをメモリに記録しておき、電圧指令値ｕ_kに応じてメモリから値を呼び出せば、計算の必要が無くなる。演算に必要とする時間と消費電力とを低減できる。
【００６７】
なお、本実施形態において、駆動部６および制御部７、ならびに、これらに含まれる最大値検出部８等の各部分は、上述の説明から明らかなように、電子部品を用いた公知の電子回路により構成してもよい。マイクロコンピュータやＤＳＰを用い、ソフトウエアによる信号処理することによって上述するような機能を実現してもよい。
【００６８】
（第２の実施形態）
本発明の回路素子駆動装置の第２の実施形態を以下に説明する。本実施形態では、レンズ駆動装置と、レンズ駆動装置を制御する回路素子駆動装置とを有するディスク装置を説明する。図３はレンズ駆動装置のレンズ駆動部２０を示している。レンズ駆動部２０は、レンズ１９と、トラッキングコイル２１と、フォーカスコイル２２と、チルトコイル２３とを備える。レンズ１９はレンズホルダ１６に保持されており、トラッキングコイル２１、フォーカスコイル２２およびチルトコイル２３がレンズホルダ１６に固定されている。トラッキングコイル２１は、実際には直列に接続された４つのコイルを含み、フォーカスコイル２２は直列に接続された２つのコイルを含んでいる。
【００６９】
これら３種類のコイルのそれぞれ一端は導電性弾性体１７ａに共通に接続されている。トラッキングコイル２１、フォーカスコイル２２、およびチルトコイル２３の他端は、導電性弾性体１７ｂ、１７ｃおよび１７ｄにそれぞれ接続されている。導電性弾性体１７ａ、１７ｂ、１７ｃおよび１７ｄはこれらのコイルへ電力を供給するとともに、レンズ駆動部２０を弾性的に支持している。本実施形態では、線状の導電性弾性体を用いているが、導電性を有する板バネや、その他の形状を有するバネ、または、バネ以外の導電性弾性体を用いてもよい。
【００７０】
レンズ駆動部２０は、磁気回路１８の空間１８Ｂに挿入されて保持される。導電性弾性体１７ｂ、１７ｃおよび１７ｄを介して３種類のコイルに電流が流れると、３種類のコイルに発生した磁力と磁気回路１８に設けられた磁石との反発あるいは吸引によってレンズ駆動部２０が所定の方向に移動する。具体的には、トラッキングコイル２１に電流を流した場合には、矢印１９Ａの方向にレンズ駆動部２０は移動する。また、フォーカスコイル２２およびチルトコイル２３に電流を流した場合には、それぞれ矢印１９Ｂおよび１９Ｃの方向へレンズ駆動部２０が移動する。このようなレンズ駆動装置は例えば特開平７−６５３９７号公報に開示されている。
【００７１】
図４は、図３に示すレンズ駆動部２０を駆動する回路素子駆動装置を示している。図４において、レンズ駆動部２０のトラッキングコイル２１、フォーカスコイル２２およびチルトコイル２３に共通に接続されている導電バネ１７ａには、共通端子２４に接続され、導電バネ１７ｂ、１７ｃおよび１７ｄは個別端子２１ａ、２２ａおよび２３ａに接続されている。
【００７２】
本実施形態の回路素子駆動装置は、駆動部６および制御部としての線形行列演算部２５を備え、第１の指令値である電圧指令値ｕ₁、ｕ₂およびｕ₃を受け取って、共通端子２４、個別端子２１ａ、２２ａおよび２３ａへ印加される駆動電圧である電圧Ｖ_com、Ｖ₁、Ｖ₂およびＶ₃を出力する。
【００７３】
電圧指令値ｕ₁、ｕ₂およびｕ₃は、トラッキングコイル２１、フォーカスコイル２２、およびチルトコイル２３に印加すべき電圧の情報を含んでいる。第１の実施形態と同様、線形行列演算部２５は、電圧指令値ｕ₁、ｕ₂およびｕ₃を受け取り、これらの電圧指令値に基づいて所定の演算を行い、その結果に基づいて、第２の指令値である、共通指令値α、補正指令値ｒ₁、ｒ₂およびｒ₃を発生させる。そして、駆動部６が、共通指令値α、補正指令値ｒ₁、ｒ₂およびｒ₃を受け取り、これらの指令値に従って、電圧Ｖ_com、Ｖ₁、Ｖ₂およびＶ₃を発生し、共通端子２４、個別端子２１ａ、２２ａおよび２３ａへ印加する。
【００７４】
駆動部６が出力可能な電圧の範囲は、電源の電圧の範囲によって制約をうけ、共通指令値αや補正指令値ｒ₁、ｒ₂およびｒ₃の絶対値が０．５を超える場合には出力電圧が飽和する。出力電圧が飽和しない場合、各コイル２１、２２および２３に印加される電圧は、次の式（数５）で定まる。
【００７５】
【数５】

【００７６】
ここで、Ｅは電源の電圧によって定まる定数である。電源が０Ｖから＋５Ｖまでとり得る片側電源の場合、Ｅ＝５Ｖである。また、電源が−５Ｖから＋５Ｖまでとりえる両側電源であれば、Ｅ＝１０Ｖである。（数５）の左辺は、３つのコイルの両端に印加される電圧である。（数５）の行列は３つのコイルと駆動部６との配線によって定まる。配線は３つのコイルへの電圧印加を独立に制御可能なように配線される。配線によって定まる行列を（数６）のように行列Ａで表す。
【００７７】
【数６】

【００７８】
続いて線形行列演算部２５の構成を説明する。線形行列演算部２５は、電圧指令値ｕ₁、ｕ₂、ｕ₃に基づいて、共通指令値α、補正指令値ｒ₁、ｒ₂、ｒ₃を出力する。詳しくは、（数７）で表されるように、線形行列演算部２５は３つの入力信号に大きさ４×３の行列Ｂをかけて４つの出力信号を生成する。
【００７９】
【数７】

【００８０】
（数７）による演算は、図４に示すように、乗算部２８ａ〜２８ｌおよび加算部２９ａ〜２９ｄによって実現される。例えば、共通指令値αは、乗算部２８ａ、２８ｅおよび２８ｉに電圧指令値ｕ₁、ｕ₂およびｕ₃を入力し、重みｂ₁₁、ｂ₁₂、ｂ₁₃をそれぞれ掛け合わせて、得られた値を加算部２９ａで足し合わせることによって得られる。
【００８１】
次に行列Ｂの１２個のパラメータ（ｂ₁₁〜ｂ₁₃、ｂ₂₁〜ｂ₂₃、ｂ₃₁〜ｂ₃₃、ｂ₄₁〜ｂ₄₃）の決定方法を説明する。図５は、上述の線形行列演算部２５のパラメータを決定するパラメータ決定部の構成を示すブロック図である。図５において、線形行列演算部２５の構成は図４と同一である。パラメータ決定部は、重み算出部２６と一般化逆行列計算部２７とを含む。重み算出部２６は、電圧指令値ｕ₁、ｕ₂およびｕ₃を受け取り、過去の電圧指令値に基づいて電圧指令値の重要度を計算する。過去の電圧指令値が大きな振幅をもっていれば、その電圧指令値はシステムにおいて重要な信号と考えられる。電圧指令値の重要度を決定する尺度として、本実施形態では時間に関するノルム値を採用する。例えば（数８）で与えられるような、電圧指令値の∞ノルムを信号の重要度の測度とする。∞ノルムは信号の振幅の最大値に相当する。
【００８２】
【数８】

【００８３】
但し、ｋ＝１、２、３である。重み算出部２６は、（数８）によって求めた重みｗ_kを一般化逆行列計算部２７へ出力する。一般化逆行列計算部２７は、重みｗ_kをパラメータに持つ重み行列Ｒを用いて、線形行列演算部２５の行列Ｂを以下のように計算する。まず、重み行列Ｒを（数９）で定義する。
【００８４】
【数９】

【００８５】
次に、重み行列Ｒを用いて（数１０）による演算を行い、行列Ｂを計算する。
【００８６】
【数１０】

【００８７】
ここで、行列Ａの右肩のＴは転置を表す。以上のように一般化逆行列計算部２７が生成する行列Ｂを線形行列演算部２５において使用する。線形行列演算部２５で用いられる行列Ｂの値は適宜更新される。
【００８８】
上記（数１０）によって与えられる行列Ｂは、駆動部６へ入力する指令値のノルムを最小にする。即ち、（数１１）で与えられる評価関数Ｊを最小にする。
【００８９】
【数１１】

【００９０】
共通指令値αの重みは、標準値を設計者が適宜決定する。上記評価関数（数１１）の変数Ｊが小さければ、駆動部６へ出力される指令値が小さくなり、出力飽和が可能な限り小さくなる。
【００９１】
つまり、上記評価関数（数１１）は、駆動部６が出力する電圧の大きさを決定するための評価関数であり、上記評価関数（数１１）が最小となるとき、電圧指令値ｕ_kに従って発生すべき電圧と、駆動部６が出力する駆動電圧との差も実質的に最小となる。
【００９２】
以上のように構成される回路素子駆動装置の動作を説明する。動作例として、トラッキングコイル２１へ電流を重点的に流し、フォーカスコイル２２とチルトコイル２３への流す電流を少なくするよう、レンズ駆動部２０を駆動する場合を考える。このような制御は、面ぶれは小さいが、偏芯が大きいディスクを用いて情報の記録および／または再生を安定して行う場合に適している。なぜならば、フォーカスコイル２２への流す電流は少なくてすむが、トラッキングコイル２１へ流す電流を多く必要とするからである。
【００９３】
具体的には、電圧指令値ｕ_kが（数１２）である場合を考える。
【００９４】
【数１２】

【００９５】
この場合、（数１２）の振幅の最大値から、重み係数を（数１３）の値のように定める。
【００９６】
【数１３】

【００９７】
上記値を用いて（数１０）を計算すると、一般化逆行列計算部２７の出力である行列Ｂは（数１４）となる。
【００９８】
【数１４】

【００９９】
続いて、（数１２）の電圧指令値ｕ_kが与えられた場合における回路素子駆動装置の動作を説明する。図６（ａ）は本実施形態の回路素子駆動装置に入力される電圧指令値の波形を示している。また、図６（ｂ）は、電圧指令値ｕ_kに基づいて線形行列部２５が演算を行い、演算結果に基づいて出力する共通指令値αおよび補正指令値ｒ_kの波形を示している。共通演算指令値αおよび補正指令値ｒ_kに基づいて駆動部６は、電圧Ｖ_comおよび電圧Ｖ_kを出力する。図６（ｃ）はコイル２１、２２、２３に印加される電位差Ｖ_k−Ｖ_comの波形を示している。これらの図において、横軸は時間を示し、縦軸は、電圧を示している。
【０１００】
図６（ａ）に示すように、電圧指令値ｕ₁は振幅０．８の正弦波であり、最大値の絶対値は０．５を超える。しかし、図６（ｂ）に示すように、補正指令値ｒ_kおよび共通指令値αの絶対値は常に０．５を超えることはなく、±０．５の範囲に収まっている。つまり、駆動部６において、出力が飽和することがない。
これは、出力飽和を生じにくくするために、（数１４）で与えられる評価関数の変数Ｊが最小となるよう、行列Ｂを決定しているからである。
【０１０１】
各補正指令値ｒ_kの最大値の絶対値が０．５を超えないようにしながら、コイル２１、２２、２３に印加しうる最大電圧を低下させないために、コイル２１、２２、２３に共通に接続される共通端子２４へ印加する電圧Ｖ_comを変化させている。図６（ｂ）に示すように、電圧Ｖ_comを発生させるための共通指令値αは、おおよそ補正指令値ｒ₁の波形と極性が反転している波形を示す。このため、コイル２１の両端に印加される実際の電位差は、図６（ｃ）に示すように、±４Ｖとなる。
【０１０２】
電圧指令値ｕ₂およびｕ₃について検討してみると、図６（ａ）および（ｂ）から分かるように、補正指令値ｒ₂およびｒ₃は、電圧指令値ｕ₂およびｕ₃と位相が異なっており、また、補正指令値ｒ₂およびｒ₃の最大値の絶対値が、電圧指令値ｕ₂およびｕ₃よりも大きくなっている。しかし、図６（ｃ）に示すように、コイル２２およびコイル２３の両端に印加される電圧Ｖ₂−Ｖ_comおよびＶ₃−Ｖ_comは、電圧指令値ｕ₂およびｕ₃と同じ位相であり、また、電圧指令値ｕ₂およびｕ₃にほぼ比例した値になっている。
【０１０３】
このように、共通端子を電源電圧の中点に固定する従来の駆動方法では、最大振幅を２．５Ｖ以上にすることができないが、本実施形態によれば、４Ｖの電圧を印加することが可能となる。
【０１０４】
上記実施形態では、過去の電圧指令値に基づいて電圧指令値の重要度を計算し、行列Ｂの値を変化させていた。このような行列を使う場合、入力される電圧指令値と、コイル２１、２２、および２３の両端に印加される電圧の電位差との適合性は高くなる。また、重みｗ_kとして∞ノルムを用いたが、ユークリッドノルム（信号の自乗平均）などの他のノルムを用いても同様に効果がある。また、電圧指令値の重要度を過去の電圧指令値の大きさに限って説明したが、設計者の意図する重み係数を用いてもよい。
【０１０５】
行列Ｂとして定数を用いることもできる。例えば、重み行列Ｒが単位行列である場合、行列Ｂは（数１５）のように対称性の良い形式となる。
【０１０６】
【数１５】

【０１０７】
行列Ｂの対称性が良い場合、演算の線形性を利用して、制御部である線形行列演算部の構成を簡略にできる。図７は本実施形態の変形例を示すブロック図である。線形行列演算部２５は、加算部２９ｅ〜２９ｈと乗算部２８ｍを備えている。図７に示すように、加算部２９ｅは、電圧指令値ｕ₁、ｕ₂、ｕ₃を加え、合計した値を乗算部２８ｍへ出力する。乗算部２８ｍは、この値に−１／４を乗じ、共通指令値αとして出力する。
【０１０８】
加算部２９ｆ、２９ｇおよび２９ｈでは、共通指令値αと電圧指令値ｕ₁、ｕ₂、ｕ₃とをそれぞれ加え、補正指令値ｒ₁、ｒ₂、ｒ₃として出力する。この線形行列演算部２５によれば、対称性を利用して乗算部を減らすことが出来るため、演算速度を向上させ、消費電力を低減することができる。
【０１０９】
なお、本実施形態において、駆動部６、線形行列演算部２５、重み算出部２６および一般化逆行列計算部２７などは、上述の説明から明らかなように、電子部品を用いた公知のアナログ回路により構成することができる。また、これらを、マイクロコンピュータやＤＳＰを用い、ソフトウエアによって信号を処理し、上述するような機能を実現してもよい。
【０１１０】
（第３の実施形態）
本実施形態の回路素子駆動装置も、第２の実施形態と同様、光ディスクドライブ装置などのレンズ駆動装置を駆動する。回路素子駆動装置は、ＰＷＭ制御を行う。
【０１１１】
図８は、本実施形態の回路素子駆動装置を示すブロック図である。第２の実施形態と同様、レンズ駆動部２０は、トラッキングコイル２１と、フォーカスコイル２２と、チルトコイル２３とを備えている。第２の実施形態で詳しく説明したように、３つのコイルの一端は、共通に１つの導電性弾性体に接続されており、それぞれのコイルの他端は、それぞれ導電性弾性体に接続されている。共通に接続された導電性弾性体および、トラッキングコイル２１、フォーカスコイル２２、およびチルトコイル２３へ接続された導電性弾性体が、それぞれ共通端子２４、個別端子２１ａ、２２ａ、および２３ａへ接続される。
【０１１２】
本実施形態の回路素子駆動装置は、制御部３６と、駆動部３４とを備えている。
【０１１３】
制御部３６は、第１および第２の実施形態と同様に、トラッキングコイル２１、フォーカスコイル２２、およびチルトコイル２３への指令である電流指令値ｕ₁、ｕ₂、ｕ₃を受け取って、共通指令値αおよび補正指令値ｒ₁、ｒ₂、ｒ₃を出力する。制御部３６の具体的な回路構成は、後で詳述する。
【０１１４】
共通指令値αおよび補正指令値ｒ₁、ｒ₂、ｒ₃を受け取る駆動部３４は、デューティ可変部３５とスイッチング駆動部３０とを含んでいる。駆動部３４のデューティ可変部３５は、これらの共通指令値αおよび補正指令値ｒ₁、ｒ₂、ｒ₃を受け取り、スイッチング信号Ｙｃ、Ｙ１、Ｙ２、Ｙ３を生成する。
【０１１５】
デューティ可変部３５は、三角波あるいはのこぎり波を出力する基準信号発生器３７と、コンパレータ３８、３９、４０、４１とを備える。コンパレータ３８、３９、４０、４１は、基準信号発生器３７が出力する基準信号ｒｔと、共通指令値αおよび補正指令値ｒ₁、ｒ₂、ｒ₃とをそれぞれ比較し、その結果をスイッチング信号Ｙｃ、Ｙ１、Ｙ２、Ｙ３としてそれぞれ出力する。つまり、共通指令値αおよび補正指令値ｒ₁、ｒ₂、ｒ₃に基づくデューティ比を備えたスイッチング信号Ｙｃ、Ｙ１、Ｙ２、Ｙ３を発生させる。
【０１１６】
スイッチング駆動部３０は、スイッチング信号Ｙｃ、Ｙ１、Ｙ２、Ｙ３を受け取り、スイッチング信号Ｙｃ、Ｙ１、Ｙ２、Ｙ３に対応した電圧波形Ｖ_com、Ｖ₁、Ｖ₂、Ｖ₃を独立に出力する。このために、スイッチング駆動部３０は、独立した４つの回路を備えている。
【０１１７】
各回路は２つのトランジスタ、２つのダイオードおよび１つの信号反転素子を含む。例えば、スイッチング信号Ｙｃをうけとり、電圧Ｖ_comを共通端子２４へ出力する回路では、スイッチング信号ＹｃがトランジスタＱ１と反転素子３１とに入力され、反転素子３１の出力はさらにトランジスタＱ２へ入力される。トランジスタＱ１のコレクタは電源電圧の最大値であるＶＤＤに接続され、トランジスタＱ２のエミッタは電源電圧の最小値であるＧＮＤに接続される。トランジスタＱ１のエミッタとトランジスタＱ２のコレクタは互いに接続され電圧Ｖ_comとして出力される。ダイオードＤ１とダイオードＤ２とは、それぞれトランジスタＱ１とトランジスタＱ２のコレクタ−エミッタ間に接続され、トランジスタを過電圧から保護する素子として用いられる。
【０１１８】
スイッチング信号Ｙ１、Ｙ２、Ｙ３を受け取り電圧Ｖ₁、Ｖ₂、Ｖ₃を出力する回路においても、信号反転素子３２、３３、３４、トランジスタＱ３およびＱ４、Ｑ５およびＱ６、Ｑ７およびＱ８、ならびにダイオードＤ３およびＤ４、Ｄ５およびＤ６、Ｄ７およびＤ８がそれぞれ上述のように接続されている。
【０１１９】
次に、制御部３６の構成を説明する。図７に示すように、制御部３６は、共通指令値計算部４２と加算部４３、４４、４５とを含む。制御部３６に入力される電流指令値ｕ₁は、共通指令値計算部４２へ入力される。共通指令値計算部４２は、電流指令値ｕ₁に基づいて共通指令値αを出力する。共通指令値αはそのままデューティ可変部３５のコンパレータ３８へ出力される。一方、加算部４３は電流指令値ｕ₁と共通指令値αとを加算して、補正指令値ｒ₁を出力する。同様に、加算部４４は電流指令値ｕ₂と共通指令値αとを加算して、補正指令値ｒ₂を出力する。さらに、加算部４５は電流指令値ｕ₃と共通指令値αとを加算して、補正指令値ｒ₃を出力する。
【０１２０】
本実施形態において、電流指令値の一つｕ₁のみを共通指令値計算部４２へ入力しているのは、トラッキングコイル２１をフォーカスコイル２２やチルトコイル２３に比べて重点的に駆動する場合を想定しているからである。例えば、ディスクの偏芯が多く、トラッキング制御により多くの駆動力が必要となる場合である。詳細については、動作説明で述べる。
【０１２１】
共通指令値計算部４２の一例として、例えば、図９に示す回路を本実施形態においては用いる。図９に示すように、共通指令値計算部４２は、オペアンプ４６、４７、４８を含む。
【０１２２】
オペアンプ４６は抵抗Ｒ１および抵抗Ｒ２と協同して反転増幅回路を形成する。直列に接続したツェナダイオードＺＤ１とツェナダイオードＺＤ２が抵抗Ｒ２に対して並列に接続される。入力される電流指令値ｕ₁の大きさに応じて、オペアンプ４６は中間計算値βを出力する。オペアンプ４７は反転加算回路である。抵抗Ｒ４を通じて入力される電流指令値ｕ₁と抵抗Ｒ３を通じて入力される信号βとの和を、抵抗Ｒ３および抵抗Ｒ４と抵抗Ｒ５との比で定まるゲインで共通指令値αとして出力する。
【０１２３】
以上の構成において、抵抗Ｒ１、抵抗Ｒ２、抵抗Ｒ３、抵抗Ｒ４、抵抗Ｒ５はいずれもおおよそ同じ抵抗値を有している。オペアンプ４８はバッファであり、電流指令値ｕ₁と中間計算値βとを加算した値である出力不足量ｓ１を出力する。出力不足量ｓ１は共通指令値αが零となる場合において、トラッキングコイル２１の出力がどれくらい不足しているかを計算した値である。出力不足量ｓ１については後述する。なお、共通指令値αは出力不足量ｓ１を反転した値にな
っている。
【０１２４】
以上のように構成された回路素子駆動装置の動作を説明する。図１０は制御部３６の共通指令値計算部４２における、電流指令値ｕ₁と中間計算値βとの関係を示している。図１０において、横軸および縦軸は、電流指令値ｕ₁および中間計算値βをそれぞれ示しており、これらの値は正規化されている。
【０１２５】
オペアンプ４６は、抵抗Ｒ１と抵抗Ｒ２との比の値で入力ｕ₁を反転増幅する。しかし、抵抗Ｒ２に対して並列に接続されたツェナダイオードＺＤ１およびＺＤ２によって、電圧のフィードバックが制限されるため、適当な電圧で出力が制限される。本実施形態においては、絶対値０．５で出力を制限するよう、適当なツェナダイオードＺＤ１およびＺＤ２が選ばれている。
【０１２６】
電流指令値ｕ₁の絶対値が０．５以下である場合には、電流指令値ｕ₁を反転し、中間計算値βとして反転した値を出力する。一方、電流指令値ｕ1の絶対値が０．５より大きいである場合には、電流指令値ｕ1の符号を反転し、絶対値が０．５の信号を中間計算値βとして出力する。
【０１２７】
絶対値０．５で飽和する中間計算値βを作り出す目的は、駆動部３４（デューティ可変部３５およびスイッチング駆動部３０）の電圧飽和モデルを制御部３６内部に設けて、出力飽和に関する情報を得るためである。電流指令値ｕ₁をそのまま駆動部へ出力する場合、電流指令値ｕ₁の絶対値が０．５以下であれば、駆動部３４において、出力飽和は発生しない。しかし、絶対値が０．５を超える場合、駆動部３４の出力は飽和し、出力不足の状態となる。本実施形態では、出力不足量ｓ１を中間計算値βと電流指令値ｕ₁との加算値として求める。
【０１２８】
図１１は、電流指令値ｕ₁と出力不足量ｓ１との関係を示している。図１１において横軸は電流指令値ｕ₁を示し、縦軸は出力不足量ｓ１を示している。これらの値はいずれも正規化された電圧を示す。図から明らかなように、電流指令値ｕ₁が−０．５から０．５の範囲にあるとき出力不足量ｓ１はゼロであり、これ以外の範囲では、出力不足量ｓ１は、電流指令値ｕ₁に比例して増加する。
【０１２９】
このようにして求めた出力不足量ｓ１を用いて共通指令値αを生成し、共通端子２４の電圧を制御することによって、トラッキングコイル２１の駆動電圧の不足を解消する。出力不足量ｓ１だけ共通端子２４の出力Ｖ_comを調整すれば良いので、共通指令値αを出力不足量の反転値とする。具体的には、オペアンプ４７の出力を共通指令値αとして用いる。図１２は、図８における電流指令値ｕ₁との共通指令値αとの関係を示している。図１２において横軸は電流指令値ｕ₁を示し、縦軸は共通指令値αを示している。これらの値はいずれも正規化された電圧を示す。
【０１３０】
トラッキングコイル２１の出力不足量ｓ１を補正するときに、共通端子２４を用いて補正しているため、共通端子２４に印加される電圧は、他のフォーカスコイル２２、チルトコイル２３の駆動にも影響を与える。この影響を補正するために、共通指令値計算部４２から出力される共通指令値αは、加算部４４および加算部４５へ入力される。加算部４４および加算部４５は、電流指令値ｕ₂、ｕ₃をそれぞれ受け取って、これらの指令値と共通指令値αとの和を補正指令値ｒ₂、補正指令値ｒ₃としてそれぞれ出力する。共通指令値αは出力不足量ｓ１の反転値であるので、この加算によって、出力不足量ｓ１に対応する電圧を補正指令値ｒ₁、補正指令値ｒ₂、補正指令値ｒ₃から減じことができ、共通端子２４に印加される共通指令値αをキャンセルする。
【０１３１】
なお、共通指令値αは、加算部４３へも入力され、加算部４３において、電流指令値ｕ₁は共通指令値αと足しあわされる。電流指令値ｕ₁が０．５を超えるときには、共通指令値αが出力不足量ｓ１の反転値を持つこととなるため、この演算によって、電流指令値ｕ₁が０．５を超える場合、補正指令値ｒ₁は０．５を出力し続ける。
【０１３２】
続いて、トラッキングコイル２１の両端に印加される電圧を説明する。図１３（ａ）は、電流指令値ｕ₁、基準信号ｒｔおよび共通指令値αの時間変化を示す。図１３（ａ）において、横軸は時間であり、縦軸は正規化された電圧を示している。基準信号ｒｔは、デューティ可変部３５の基準信号発生器３７において発生し、１周期の間に一定速度で−０．５Ｖから＋０．５Ｖまで変化する、のこぎり波である。のこぎり波の振幅が０．５であるため、補正指令値ｒ_kの絶対値が０．５を超えると、基準信号ｒｔとの比較より、絶対値０．５を超えた分が無視される。すなわち、０．５を超える大きな補正指令値ｒ_kを指定しても、補正指令値は０．５であるとみなされ、スイッチング指令を変化させず、コイルの駆動に影響を与えない。
【０１３３】
図１３（ａ）において、横軸の時間は基準信号ｒｔの周期を区切として、区間Ｔ１、区間Ｔ２、区間Ｔ３に分けられる。時間が、区間Ｔ１、区間Ｔ２、区間Ｔ３と順に変化すると、電流指令値ｕ₁は−０．２、＋０．２、＋０．８と変化している。区間Ｔ１および区間Ｔ２では、電流指令値ｕ₁が±０．５以内であるため、共通指令値αはゼロである。一方、区間Ｔ３では、電流指令値ｕ₁が＋０．８であるため、定数＋０．５を０．３だけ超える。従って図１２の入出力関係より、αは−０．３となる。
【０１３４】
デューティ可変部３５において、基準信号ｒｔと共通指令値αおよび補正指令値ｒ₁とがコンパレータ３８および３９において比較され、比較結果に基づいて、スイッチング信号ＹｃおよびＹ１が出力される。
【０１３５】
図１３（ｂ）および（ｃ）は、スイッチング信号ＹｃおよびＹ１に基づいて駆動部３０が出力する電圧Ｖ_comおよびＶ₁の波形をそれぞれ示している。いずれの図も横軸は時間であり、縦軸は電圧を示す。
【０１３６】
まず、図１３（ａ）および（ｂ）を参照しながら、電圧Ｖ_comを説明する。区間Ｔ１の前半ではｒｔ＜αであるので、スイッチング信号Ｙｃはハイレベルとなる。スイッチング信号Ｙｃがハイレベルのとき、トランジスタＱ１はオン状態となり、トランジスタＱ２はオフ状態となる。このとき、共通端子２４の電圧Ｖ_comは電源電圧の最大値ＶＤＤレベルとなる。反対に区間Ｔ１の後半ではｒｔ＞αであるので、スイッチング信号Ｙｃはローレベルとなる。スイッチング信号Ｙｃがローレベルのとき、トランジスタＱ１はオフ状態となり、トランジスタＱ２はオン状態となる。したがって、共通端子２４の電圧Ｖ_comは、電源電圧の最小値ＧＮＤレベルとなる。区間Ｔ２においても同じ動作をする。この結果、区間Ｔ１の中間点および区間Ｔ２の中間点でＶ_comの電圧がＶＤＤからＧＮＤへ切り替わる。電圧Ｖ_comはデューティ指令値αと基準信号ｒｔとの大小関係が入れ替わる時点で切り替わる。区間Ｔ３でも同様にＶＤＤからＧＮＤへ電圧Ｖ_comが切り替わるが、αが−０．３であるので、切り替わり点は区間Ｔ３においてより早くなる。
【０１３７】
次に、図１３（ａ）および（ｃ）を参照しながら、電圧Ｖ₁を説明する。電圧Ｖ_comと同様に、区間Ｔ１では電流指令値ｕ₁が−０．２であるので、区間Ｔ１の前半で電圧Ｖ₁がＶＤＤからＧＮＤへ切り替わる。区間Ｔ２では電流指令値ｕ₁が＋０．２であるので、区間Ｔ２の後半で電圧Ｖ₁がＶＤＤからＧＮＤへ切り替わる。区間Ｔ３では電流指令値ｕ₁は＋０．８であるので、電流指令値ｕ₁と共通指令値αの和である補正指令値ｒ₁は、０．５（＋０．８＋（−０．３））となる。このとき、電圧Ｖ₁の切替えは発生しないため、区間Ｔ３の間、電圧Ｖ₁はＶＤＤとなる。
【０１３８】
図１３（ｄ）は、電圧Ｖ₁と電圧Ｖ_comとの差を示しており、トラッキングコイル２１の両端にかかる電圧（Ｖ₁−Ｖ_com）の波形である。区間Ｔ１において、電圧（−ＶＤＤ）がトラッキングコイル２１の両端に印加される。区間Ｔ２では、電圧（＋ＶＤＤ）がトラッキングコイル２１の両端に印加される。これらの区間Ｔ１およびＴ２において、電圧が印加される時間は、区間幅の２０％である。
また、区間Ｔ３では、共通指令値α（−０．３）による補正分だけ印加電圧時間が延長されため、電圧（＋ＶＤＤ）が区間幅の８０％の時間において印加される。電流指令値ｕ₁が上述の値以外をとる場合でも同様に動作するのは明らかであり、トラッキングコイル２１の両端にかかっている時間は、電流指令値ｕ₁に比例する。したがって、基準信号ｒｔの周期が十分速ければ、電流指令値ｕ₁に比例した電流がトラッキングコイル２１に流れる。
【０１３９】
続いて、フォーカスコイル２２の駆動を説明する。図１４（ａ）は、電流指令値ｕ₂、基準信号ｒｔおよび補正指令値ｒ₂の時間変化を示す。図１４（ａ）において、横軸は時間であり、縦軸は正規化された電圧を示している。図１４（ａ）に示す基準信号ｒｔおよび共通指令値αは、図１３（ａ）に示す基準信号ｒｔおよび共通指令値αと同一である。区間Ｔ１から区間Ｔ３において、電流指令値ｕ₂は、一定な＋０．１であるとする。この時、補正指令値ｒ₂は共通指令値αがゼロであるため、電流指令値ｕ₂に等しい。一方、区間Ｔ３では、α＝−０．３であるので、補正指令値ｒ₂は−０．２（＋０．１＋（−０．３））となる。そして、デューティ可変部３５において、基準信号ｒｔと補正指令値ｒ₂とがコンパレータ４０において比較され、比較結果に基づいて、スイッチング信号Ｙ２が出力される。
【０１４０】
図１４（ｂ）および（ｃ）は電圧Ｖ_comおよび電圧Ｖ₂の波形を示しており、図１４（ｄ）はフォーカスコイル２２の両端に印加される電圧（Ｖ₂−Ｖ_com）の波形を示している。いずれの図も横軸は時間を示し、縦軸は電圧を示す。
【０１４１】
図１３（ａ）、（ｂ）、（ｃ）を参照して説明したように、区間Ｔ１およびＴ２では、電流指令値ｕ₂と共通指令値αに基づいて、電圧Ｖ₂および電圧Ｖ_comが発生させられるため、フォーカスコイル２２の両端には、電圧（＋ＶＤＤ）が区間幅の１０％の時間において印加される。区間Ｔ３においては、電流指令値ｕ₂が区間Ｔ１およびＴ２と同じ＋０．１であるのもかかわらず、共通指令値αが−０．３であるため、補正指令値ｒ₂は−０．２となる。つまり、共通指令値αによって変化してしまう電圧Ｖ_comの変化量を補うために、補正指令値ｒ₂を調整する。このため、フォーカスコイル２２の両端に印加される電圧（Ｖ₂−Ｖ_com）としては、区間Ｔ１およびＴ２と同じ値になる。
【０１４２】
ただし、区間Ｔ３において、共通指令値が−０．３であるので、電流指令値ｕ₂によって出力可能な電流に制限がある。具体的には、フォーカスコイル２２へ電圧（＋ＶＤＤ）を印加できる最大時間は区間幅の２０％までとなる。また、電圧（−ＶＤＤ）を印加できる最大時間は区間幅の８０％までとなる。チルトコイル２３もフォーカスコイル２２と同じように駆動される。
【０１４３】
上記説明から明らかなように、共通端子２４に印加する電圧Ｖ_comは電源電圧の中点ＶＤＤ／２に固定されるのが一般的であった。本実施形態は、ＶＤＤとＧＮＤとを交互にスイッチングして、電圧Ｖ_comに印加する点で従来技術とは大きく異なっている。電圧Ｖ_comを交互にスイッチングすることで、１つの回路素子に印加できる瞬時の最大電圧を±ＶＤＤにできるという利点がある。また、電圧Ｖ_comのスイッチングのデューティを５０％に固定せず、電流指令値ｕ₁から求めた出力不足量ｓ１を用いて共通指令値αを補正することによって、トラッキングコイル２１に電圧を印加する時間割合を５０％以上に増すことができる。
【０１４４】
本実施形態によれば、トラッキングコイル２１へ重点的に電流を流し、フォーカスコイル２２およびチルトコイル２３へ流す電流には部分的に制限を加えている。このため、フォーカスコイル２２への電流は少なくてよいが、トラッキングコイル２１多く電流を流すことが必要な、面ぶれが少なく、偏芯の多いディスクを利用する場合に本実施形態は適している。
【０１４５】
なお、面ぶれが多く、偏芯の少ないディスクを利用して情報の記録／再生を行う場合には、フォーカスコイル２２への電流を増し、トラッキングコイル２１への電流を少なくすれば良い。このためには、上記実施形態において、トラッキングコイル２１の制御方法とフォーカスコイル２２の制御方法とを入れ替えることによって、安定して情報の記録／再生を行うことができる。
【０１４６】
以下に、本実施形態の変形例を説明する。図１５は、本実施形態の制御部３６の変形例である制御部５６を示すブロック図である。制御部５６は、図８に示す制御部３６と共通指令値計算部５２の構成が異なっている。加算部４３、加算部４４、加算部４５は図８の制御部３６に用いられるものと同じである。
【０１４７】
図１５に示すように、共通指令値計算部５２は、出力不足量算出部５０を３つ備えており、それぞれ、電流指令値ｕ_kを入力し出力不足量ｓ_kを出力する。ここで、ｋはｋ＝１、２、３の整数である。出力された出力不足量ｓ_kは、最大値検出部８および最小値検出部９に入力される。最大値検出部８および最小値検出部９はそれぞれ、出力不足量の最大値Ｓ_maxと出力不足量の最小値Ｓ_min（負の出力で不足する最大量）を出力する。最大値Ｓ_maxと最小値Ｓ_minは反転加算部４９で加算され、符号を反転して出力される。
【０１４８】
共通指令値計算部４２の動作は、図８に示される共通指令値計算部４２と同様の働きをするが、出力不足量をトラッキングコイル２１についてのみ考えるのではなく、全てのコイルについて求め、出力不足量ｓ_kの最大値および最小値を最大値検出部８および最小値検出部９で検出する点が図８に示される共通指令値計算部４２とは異なる。
【０１４９】
なお、本実施形態では、３個のコイルを駆動する場合について述べたが、コイルは４個あるいはそれ以上を駆動させる場合にも好適に本発明を適用できる。ｎ個のコイルを駆動するためには（ｎ＋１）個の駆動回路を準備すれば良い。またコイル１つあたりの回路を簡単にすることができるため、本発明の実施は容易である。
【０１５０】
また、以上の実施形態は、駆動部３４および制御部３６を公知のアナログ回路を用いた演算処理によって実現しているが、マイコンあるいはＤＳＰ（Digital Signal Processor）を用い、ソフトウエアによるタイマー処理によって入出力ポートのビットを周期的に反転させた信号を、スイッチング駆動部３０へ出力することによっても実現することができる。この場合、ｎ個のコイルあるいは回路素子を駆動するのに必要なビット数は（ｎ＋１）である。
【０１５１】
（第４の実施形態）
本発明の回路素子駆動装置の第４の実施形態を以下に説明する。
【０１５２】
本実施形態の回路素子駆動装置は、図８に示される回路素子駆動装置と同じ構成を備えており、共通指令値計算部４２における演算方法が異なっている。本実施形態では、入力指令値ｕ_kが大きく、出力不足が発生する場合に、出力不足の割合を、特定のコイルに偏らないように共通指令値αを決定する。本実施形態における演算にはＤＳＰを用いる。以後の説明は、共通指令値αを演算する手順について説明する。
【０１５３】
まず、以後の説明において、ｋはコイル番号を表す整数とする。電圧指令値ｕ_kは与えられるとし、共通指令値αは演算により求める未知パラメータである。出力不足量ｓ_kを共通指令値αを含む次式（数１６）で定義する。
【０１５４】
【数１６】

【０１５５】
ここで、ｓｇｎ（ｘ）は（数１）で定義される符号関数である。ｑは定数０．５である。出力不足量ｓ_kが負であれば、ｋ番目のコイルは電圧指令値ｕ_kどおりに駆動され、出力不足量ｓ_kが正であれば、ｋ番目のコイルは電流の駆動不足状態となる。
【０１５６】
次に、出力不足量ｓ_kを引数とする評価関数を（数１７）で定義する。
【０１５７】
【数１７】

【０１５８】
ｗ_kは重み係数であり、評価関数J（α）は重み係数ｗ_kをかけたｓ_kの中で最大値を出力する。重み係数ｗ_kは、予め設計者がシステムへの影響度を見積もった定数であっても良く、電圧指令値ｕ_kの時間に関するノルムより求めた値でも良い。例えば、重み係数ｗ_kを電圧指令値ｕ_kの最大振幅の逆数とすれば、（ｗ_k・ｓ_k）は、ｋ番目のコイルにおける電圧指令値の最大振幅に占める不足割合を表す。（数１７）で定義する評価関数を最小にすれば、特定のコイルにおいて電圧指令値の最大振幅に占める不足割合が際だって大きくなることはない。即ち、駆動電圧の不足が特定のコイルに集中することがなくなる。
【０１５９】
次に、上記（数１７）で定義される評価関数を最小にする共通指令値αを求める手順を説明する。まず、整数ｉと整数ｊをコイルの番号とする。電圧指令値ｕ_iと、電圧指令値ｕ_iと符号の異なる電圧指令値ｕ_jについて、共通指令値の候補α_ijを（数２）を用いて求める。
【０１６０】
引き続き、求めたα_ijの中から、（数１７）で定義される評価関数を最小にするαを選出する。以上が、共通指令値αを求める手順である。なお、電圧指令値が同符号（ｓｇｎ（ｕ_i）・ｓｇｎ（ｕ_j）＝１）の場合を演算過程で省略するのは、無意味な解を求めるステップを省き、計算速度を向上させるためである。
【０１６１】
なお、（数２）は第１の実施形態と深く関連しており、（数３）を拡張した計算式である。例えば、全てのｗ_kが等しい場合に（数２）が得られる。即ち、本実施形態の演算は、第１の実施形態の演算において信号の重みを考慮したものになっている。
【０１６２】
以下に本実施形態の共通指令値計算部４２における演算の例を説明する。（表１）に電圧指令値ｕ_kの振幅、重み係数ｗ_k、電圧指令値ｕ_kを示す。（表１）によって与えられた数値を用いて（ｗ_k・ｓ_k）を計算した結果を図１６に示す。図１６は、本実施形態における（ｗ_k・ｓ_k）と共通指令値αの関係を示している。図１６において、縦軸は（ｗ_k・ｓ_k）の値を示し、横軸は共通指令値αを示している。
【０１６３】
【表１】

【０１６４】
一方、（数２）を用いて共通指令値αの候補α_ijを求めると（表２）となる。（表２）において、（ｉ、ｊ）の組み合わせが（１、２）、（１、３）、（１、４）の場合にｕ_iとｕ_jが互いに異符号となる。求めたα_ijについて評価関数を求めると（ｉ、ｊ）＝（１、２）の場合に評価関数Ｊ（α）が最小となる。図１６より明らかなように、各（ｗ_k・ｓ_k）の最大値が最小となる点を探索すれば、点Ｑ１であり、計算結果に一致する。求めたα＝−０．０３５を共通指令値として出力する。以上で計算手続きは終了である。
【０１６５】
【表２】

【０１６６】
このようにして求めた共通指令値αの値の効果を共通指令値αがゼロである場合と比較する。（表３）は（ｗ_k・ｓ_k）の値をα＝−０．０３５と、α＝０とについて計算した結果である。補正が無いα＝０の場合、ｋ＝１のコイルの出力不足は（ｗ１・ｓ１）＝０．３３であり、電圧指令値の振幅０．９の３３％が不足である。同様にｋ＝２のコイルの出力不足は、（ｗ２・ｓ２）＝０．２５であり、電圧指令値ｕ₂の振幅０．８に対して２５％の不足である。
【０１６７】
【表３】

【０１６８】
一方、α＝−０．０３５の場合、ｋ＝１のコイルとｋ＝２のコイルの出力不足はそれぞれ０．２９となり、電圧指令値の振幅の２９％が不足となる。つまり、ｋ＝１のコイルの駆動電圧を他のｋ＝２およびｋ＝３のコイルから分配することによって、ｋ＝１およびｋ＝２のコイルの不足量が同程度になる。
【０１６９】
以上の計算では（数１７）で表される評価関数Ｊ（α）を最小にするようにαを定めた。次に、出力不足量の２乗和が最小になる評価関数について述べる。出力不足量の２乗和は不足エネルギの和に相当し、複数のコイル駆動が同時に出力不足となる場合に、出力不足の総エネルギを最小に抑えて安定化をはかるのである。具体的に式で表すと、（数１８）で与えられる正値関数を用いて表される（数１９）の評価関数を最小にする共通指令値αを計算する。
【０１７０】
【数１８】

【０１７１】
【数１９】

【０１７２】
ここで、ｍは適当な正数であり、ｍ＝２とする。ｍ＝２以外の場合は後述する。ｍは設計者が適宜定めることのできるパラメータである。
【０１７３】
（数１９）に示す評価関数Ｊを最小にするαの演算手順は、探索によって行う。探索部は公知の手法を用いることができるので、ここではその説明を省略する。なお、探索の初期値α₀は（数１７）を用いて選出すれば、解に近い点より探索を開始するので効率が良い。また、解はα＝０近傍に存在する場合が多いので、初期の探索方向はα＝０に向かって行えば、さらに効率がよい。
【０１７４】
（数１９）で定義した評価関数の計算結果を（表３）と図１７を用いて説明する。図１７は、共通指令値αと評価関数の値との関係を示している。図１７において、横軸は共通指令値αであり、縦軸は評価関数Ｊ（α）の値である。黒三角印は（数１７）の評価関数をプロットした線であり、点Ｑ１で最小となる。白四角印「□」は（数１９）の評価関数においてｍ＝２の場合のプロットであり、点Ｑ２で最小となる。点Ｑ２では、αの値は−０．００９であり、このαを共通指令値として出力すれば、不足エネルギの和が最小という意味で、システムがより安定になる。
【０１７５】
次に「×」印は（数１９）の評価関数でｍ＝４の場合のプロットであり、点Ｑ３で最小となる。点Ｑ３ではαの値は−０．０３である。各評価関数のプロットを比較すると、ｍが大きな数になれば、（数１９）は（数１７）へ漸近する。（数１９）で与えられる評価関数は（数１７）を拡張した計算式だからである。（表３）の点Ｑ１（α＝−０．０３５）と、点Ｑ２（α＝−０．００９）と、点Ｑ３（α＝−０．０３）とについて計算した結果を比較すると、出力不足ｓ_kの値が点Ｑ１と点Ｑ２の間に点Ｑ３の結果がある。即ち、個々のコイル毎の出力不足量を最小にすることを重視するのか、トータルのエネルギ不足量を最小にすることを重視するのかを、ｍの値を適宜決定することにより行うことができる。
このように、本実施形態によれば、出力不足が生じる場合、（数１７）や（数１９）を用いて共通指令値αを決定することによって、特定のコイルに出力不足が偏ってしまうようなシステムへの悪影響を抑制できる。
【０１７６】
上記第１から第４の実施形態では、本発明の回路素子駆動装置が駆動する回路素子として、モータのコイルおよびレンズ駆動装置のコイルを例示したが、その他の種々の回路素子を本発明の回路素子駆動装置によって駆動してもよい。
【０１７７】
例えば、複数のモータを備えた多関節ロボットを駆動する場合に本発明の回路素子駆動装置を好適に用いることができる。多関節ロボットは数多くのモータを内蔵するが、モータが関節の自由度の数以上に必要となるため、モータに接続される配線数が多くなる。一方、多関節ロボットのモータはトルクを多く必要とするため、各モータに印加する電圧を低く出来ない。このような場合、本発明の回路素子駆動装置を用いることによって、印加電圧を低下させずに配線数を減らすことができる。また、多関節ロボットに限らず、本発明による制御方法は、他のさまざまな分野においても適用が可能である。
【０１７８】
【発明の効果】
本発明の回路素子駆動装置によれば、配線数削減のために共通端子を備えた複数の回路素子を駆動する場合に、１つの回路素子に印加できる瞬時の最大電圧を低下させず、各々の回路素子を独立に駆動できる。また、出力が不足する回路素子に対して、電力を再配分する機能をもつ。特に出力が全般に不足する場合は、駆動装置への影響が最小になるように回路素子への給電割合を変化させることができる。特に、レンズ駆動装置で３つのコイルを独立に駆動したい場合、必要な端子の数を４つにすることができる。したがって、余分な配線を必要とせず、レンズを支持する導電性弾性体への悪影響をなくすことができる。さらに、配線の工数を削減できる。
【０１７９】
また、入力指令値から駆動部の指令値を作成する場合に、駆動部の指令値のノルムを最小に設定することができるので、出力飽和が起こりにくいという利点がある。また指令値の演算を乗算部および加算部のみで構成される線形行列演算部によって行えるので、指令値の演算を高速に行うことができる。
【０１８０】
また、駆動部の出力不足量を求める非線形な演算処理を内蔵することにより、駆動部の出力飽和を効果的に避けることができる。さらに出力不足量を設計者の意図する重み付けした評価関数を用いて評価することにより、電力の再配分を詳細に設定することができる。評価関数を適宜選択することによって、個々の回路素子の出力不足量を最小にすることを重視したり、全体のエネルギ不足量を最小にすることを重視したりすることができる。そして、評価関数を最小にする共通指令値αを効率よく求めることができる。
【０１８１】
また、本発明の回路素子駆動装置は、スピンドルモータの駆動にも利用できる。共通端子を一定電圧に固定した場合に比べて、約１６％波高の高い電流で駆動できる。さらに、スピンドルモータを駆動する場合のように、周期信号によって回路素子を駆動する場合、共通指令値などをメモリに蓄えておけば、演算回路の削減と、演算処理に要する時間節約と、消費電力削減が行えるという利点がある。
【０１８２】
また、本発明によれば、ｎ個の回路素子を駆動するために、（ｎ＋１）個の駆動回路を準備すればよい。このため、２ｎ個の駆動回路が必要であった従来技術に比べ、回路素子１つあたりの回路を簡素に構成できる。さらに、スイッチング指令をＤＳＰやマイコンのＩ／Ｏポートで行う場合、ｎ個のコイルを駆動するのに必要なビット数は（ｎ＋１）だけで良い。
【図面の簡単な説明】
【図１】本発明による回路素子駆動装置の第１の実施形態を示すブロック図である。
【図２】図１に示す回路素子駆動装置の動作を説明するため波形を示している。
【図３】本発明の回路素子駆動装置の第２の実施形態実施であって、レンズ駆動装置を示す斜視図である。
【図４】図３に示すレンズ駆動装置を駆動する回路素子駆動回路を示すブロック図である。
【図５】図５に示す回路素子駆動装置の線形行列演算部に用いられるパラメータを決定するパラメータ決定部の構成を示すブロック図である。
【図６】（ａ）、（ｂ）、（ｃ）は図４に示す回路素子駆動装置の動作を説明するための波形を示している。
【図７】図４に示す回路素子駆動装置の線形行列演算部の変形例を示すブロック図である。
【図８】本発明による回路素子駆動装置の第３の実施形態を示すブロック図である。
【図９】図８に示す回路素子駆動装置の共通指令値計算部の具体的な構成を示す回路図である。
【図１０】図９における電流指令値ｕ₁との中間計算値βとの関係を示すグラフである。
【図１１】図９における電流指令値ｕ₁との出力不足量ｓ１との関係を示すグラフである。
【図１２】図９における電流指令値ｕ₁との共通指令値αとの関係を示すグラフである。
【図１３】（ａ）、（ｂ）、（ｃ）は、トラッキングコイル２１へ印加される電圧を生成するための動作を説明する波形を示している。
【図１４】（ａ）、（ｂ）、（ｃ）は、フォーカスコイル２２へ印加される電圧を生成するための動作を説明する波形を示している。
【図１５】図８に示す回路素子駆動装置の制御部の変形例を示すブロック図である。
【図１６】本発明による回路素子駆動装置の第４の実施形態における（ｗ_k・ｓ_k）と共通指令値αの関係を示すグラフである。
【図１７】本発明による回路素子駆動装置の第４の実施形態における共通指令値αと評価関数との関係を示すグラフである。
【図１８】従来の２端子回路素子の駆動方法を説明する回路図である。
【図１９】他の従来の２端子回路素子の駆動方法を説明する回路図である。
【符号の説明】
１ スピンドルモータ
２、３、４ コイル
５、２４ 共通端子
６ 駆動部
７、３６、５６ 制御部
８ 最大値検出部
９ 最小値検出部
１０ 反転平均部
１１、１２、１３、２９、４３、４４、４５ 加算部
α 共通指令値
ｒ₁、ｒ₂、ｒ₃ 補正指令値
Ｖ_com 共通端子への印加電圧
Ｖ₁ 個別端子２ａへの印加電圧
Ｖ₂ 個別端子３ａへの印加電圧
Ｖ₃ 個別端子４ａへの印加電圧
２０ レンズ駆動部
２１ トラッキングコイル
２２ フォーカスコイル
２３ チルトコイル
２５ 線形行列演算部
２６ 重み算出部
２７ 一般化逆行列計算部
２８ 乗算部
３０ スイッチング駆動部
３１、３２、３３、３４ 反転素子
３５ デューティ可変部
３７ 基準信号発生器
３８、３９、４０、４１ コンパレータ
４２、５２ 共通指令値計算部
４６、４７、４８ オペアンプ
４９ 反転加算部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for driving a circuit element and a method for driving the circuit element.
[0002]
[Prior art]
In order to apply a voltage to a two-terminal circuit element typified by a coil or a resistor, two wires are required for each circuit element. Therefore, for example, if a voltage is to be applied independently to three coils, six wires are required.
[0003]
As an example of a device that should apply a voltage independently to a plurality of two-terminal circuit elements, there is a lens driving device used in an optical disk device. For example, as disclosed in Japanese Patent Application Laid-Open No. 7-65397, a technique for correcting the tilt between a disk and the optical axis of an optical head with the tilt of an objective lens driven by a lens driving device is conventionally known. .
[0004]
In such an apparatus, three types of coils are used to drive the objective lens with three degrees of freedom. Specifically, a tracking coil that drives the objective lens in the tracking direction, a focus coil that drives the objective lens in the focus direction, and a tilt coil that drives the objective lens with respect to the disk are used.
[0005]
In general, power is supplied to these coils through four conductive springs that hold an objective lens. For example, when three coils are driven individually, the tracking coil and the focus coil are energized through four conductive springs, and the remaining tilt coils are energized by drawing a thin line to an external circuit.
[0006]
[Problems to be solved by the invention]
However, when such a connection is made, the wiring for energizing the tilt coil acts as a load on the four conductive springs supporting the objective lens, which causes the spring constant to vary. End up. In addition, it is necessary to connect the wiring to the tilt coil or to fix the wiring so that the connected wiring becomes an equal load on the four conductive springs.
[0007]
On the other hand, when one end of each of the three coils is connected as a common terminal, and three wires connected to one end of each coil and one wire connected to the common terminal are assigned to four conductive springs, the above-described problem is Solved. However, in this case, there arises a problem that the maximum voltage that can be applied to the coil is reduced to half. This problem is described in detail below.
[0008]
For example, consider a case where a coil is driven using a 5V DC power supply as a power supply voltage. As shown in FIG. 18, three coils 102a, 102b, and 102c are connected to switching elements 101a, 101b, and 101c, respectively. In this case, it is necessary to connect wiring to a total of six terminals for the three coils 102a, 102b, and 102c. If the switches are switched so that both ends of each coil can be connected to either the high potential side 105H or the low potential side 105L of the power supply voltage 105, the voltage that can be applied to both ends of each coil is -5V to The value is in the range of + 5V.
[0009]
On the other hand, as shown in FIG. 19, when one end of the three coils 102a, 102b, and 102c is connected to the reference potential as a common terminal, the other end of the three coils 102a, 102b, and 102c is on the high potential side of the power supply voltage 105. The switching elements 103a, 103b, and 103c are connected so that they can be connected to either 105H or the low potential side 105L. By providing the common terminal, the number of terminals necessary for driving the three coils 102a, 102b, and 102c is four. However, in this case, as shown by the broken line 107 in FIG. 19, when the low potential side 105L of the power supply voltage 105 is connected to the reference potential, the voltage that can be applied to each element is 0V to + 5V, and the reverse voltage is Cannot be applied. In order to be able to apply a voltage in the reverse direction as well, it is necessary to use the midpoint of the power supply voltage 105 as a reference potential as shown by the solid line 106 instead of the broken line 107. In this case, it can be applied to each element. The voltage is −2.5 to + 2.5V.
[0010]
Thus, in the above lens driving device, when one end of three coils is connected as a common terminal and each coil is driven, the instantaneous maximum voltage that can be applied to one coil is reduced to half. . As a result, the thrust of the lens driven by each coil is reduced. For example, when a disk having a track eccentricity larger than a standard value is mounted on the disk device, the lens driving thrust in the tracking direction is insufficient. Further, when a disc having a disc surface shake amount larger than a standard value is mounted on the disc device, the lens driving thrust in the focus direction is insufficient. When such a disc is used, for example, when the disc is reproduced at a high speed, there arises a problem that information cannot be correctly reproduced from the disc.
[0011]
The present invention solves such problems of the prior art, and can reduce the wiring required to drive a plurality of circuit elements while not reducing the instantaneous maximum voltage that can be applied to the circuit elements. The present invention relates to a driving device and a driving method of a circuit element.
[0012]
[Means for Solving the Problems]
The circuit element driving device of the present invention receives n first command values for generating a voltage to be applied to n (n is an integer of 2 or more) circuit elements having two terminals, and the n Control means for generating and outputting p second command values (p is an integer of (n + 1) or more and less than 2n) based on the first command values, and the p second commands Driving means for generating and outputting p drive voltages based on the command value, wherein at least one of the p drive voltages is based on at least one of the first command values. And is applied in common to one terminal of each of the two or more circuit elements.
[0013]
In a preferred embodiment, the control means sets the second command value so that an evaluation function related to the drive voltage is substantially minimized.
[0014]
In a preferred embodiment, the control means substantially minimizes a difference between a voltage to be applied to the circuit element based on the first command value and the drive voltage generated by the drive means. Then, the second command value is generated.
[0015]
In a preferred embodiment, the control means includes linear matrix calculation means.
[0016]
In a preferred embodiment, the linear matrix calculation means multiplies the n first command values by a general inverse matrix of size p × n and outputs the p second command values.
[0017]
In a preferred embodiment, the general inverse matrix is a general inverse matrix that minimizes the norm of the second command value.
[0018]
In a preferred embodiment, the general inverse matrix is a general inverse matrix that minimizes a norm with a weight coefficient of the second command value.
[0019]
In a preferred embodiment, the control means changes the weighting factor based on a history of the first command value.
[0020]
In a preferred embodiment, the weighting factor is determined using a norm related to the time of the first command value.
[0021]
In a preferred embodiment, the drive means includes p duty variable means for outputting a switching signal for changing the duty based on the second command value, and a maximum power supply voltage or a power supply voltage by the switching signal. And p switching driving means for alternately switching and outputting the minimum value of each.
[0022]
In a preferred embodiment, the duty variable means includes a microcomputer or a digital signal processor (DSP), and a signal obtained by periodically inverting the bit of the input / output port by software timer processing using the microcomputer or DSP. Is output to the switching drive means.
[0023]
In a preferred embodiment, the first command value is a periodic signal, and at least one of the second command values calculated in advance is stored in a predetermined storage device, and the first command value The second command value is extracted from the storage device in synchronization with the cycle and output to the driving means.
[0024]
In a preferred embodiment, the n is 3, the p is 4, and one of the four drive voltages is commonly applied to one end of each of the three two-terminal circuit elements.
[0025]
In a preferred embodiment, p is an integer larger than n, and the driving means connects a common terminal to which one end of each of the n circuit elements is connected, and another end of each of the n circuit elements. (N + 1) drive voltages to be respectively applied to n individual terminals provided independently are generated, and the control means receives the n first command values and receives the (n + 1) drive voltages. (N + 1) second command values are output to the driving means so as to generate a voltage.
[0026]
In a preferred embodiment, k is an integer from 1 to n that represents the number of the circuit element, and the control means includes the n first command values u. _k The maximum value u _max And a maximum value detecting means for detecting the n first command values u _k Minimum value u _min Minimum value detecting means for detecting at least u _max And u _min Are used to generate the second command value α for generating a drive voltage to be applied to the common terminal, and the second command value α is used as the n first command values u. _k N number of second command values r given to the individual terminals _k Is generated.
[0027]
In a preferred embodiment, the control means has a maximum value u. _max And the minimum value u _min And the second command value α is generated.
[0028]
In a preferred embodiment, the driving means includes a non-saturation range that generates the driving voltage proportional to the second command value, and a saturation that generates a constant driving voltage regardless of the second command value. A non-linear function having a range, and the control means calculates the (n + 1) second command values using a non-linear relationship from the n first command values, and k is the circuit element. In the control means, when the (n + 1) second command values are larger than the maximum value of the non-saturation range or smaller than the minimum value, The n first command values u for the non-saturation range _k N output deficiencies s _k The output shortage amount calculating means given as _k The second command value α to be given to the common terminal is generated using at least one of the first command value u and the second command value α is used as the n first command values u. _k And the n second command values r given to the individual terminals _k Is generated.
[0029]
In a preferred embodiment, the control means includes the n output deficiencies s. _k Is used to determine the second command value α so as to minimize the evaluation function.
[0030]
In a preferred embodiment, the evaluation function is the output shortage amount s. _k This function outputs the maximum value of.
[0031]
In a preferred embodiment, the evaluation function is a weighting factor w. _k It is a function weighted by.
[0032]
In a preferred embodiment, the procedure for obtaining the second command value α includes the first command value u of the i-th circuit element. _i And the command value u _i The first command value u of the j-th circuit element having a sign different from that of the first command value u _j A plurality of second command value candidates α using a predetermined calculation formula relating to _ij The plurality of second command value candidates α _ij To select the second command value α that minimizes the evaluation function.
[0033]
In a preferred embodiment, the command value candidate α _ij Is a weighted coefficient w _k And a predetermined constant q and a sign function sgn (x) defined by (Equation 1), is expressed as (Equation 2).
[0034]
In a preferred embodiment, the evaluation function includes an output shortage amount s. _k Use the norm of
[0035]
In a preferred embodiment, the procedure for obtaining the second command value α includes the first command value u of the i-th circuit element. _i And the command value u _i The first command value u of the j-th circuit element having a sign different from that of the first command value u _j A plurality of initial value candidates α using a predetermined calculation formula relating to _ij The initial value candidate α _ij The initial value α that minimizes the evaluation function ₀ Is selected in the first iteration procedure, and then the initial value α ₀ Is used as a starting point, and the second command value α at which the evaluation function is minimized is searched using a second iterative procedure in which α = 0 is the initial search direction.
[0036]
In a preferred embodiment, the control means includes the n output deficiencies s. _k The maximum value s _max And a maximum value detecting means for detecting the n output deficiencies s _k Minimum value s _min Minimum value detecting means for detecting at least the maximum value s _max And the minimum value s _min Are used to generate the second command value α to be given to the common terminal.
[0037]
In a preferred embodiment, the maximum value s _max And the minimum value s _min The addition inverted output is the second command value α.
[0038]
Further, another circuit element driving device of the present invention provides n first command values for generating a voltage to be applied to n (n is an integer of 2 or more) circuit elements having two terminals. Control means for receiving and generating p second command values (p is an integer less than or equal to (n + 1) and less than 2n) based on the n first command values; Driving means for generating and outputting p driving voltages based on the second command values, and the control means commonly connects one terminal of each of the two or more circuit elements. The second command value corresponding to the drive voltage to be applied to the common terminal is generated based on at least one of the first command values.
[0039]
In a preferred embodiment, the control means outputs the second command value corresponding to a drive voltage to be applied to each other individual terminal that is not the common terminal of the two or more circuit elements. Generate based on the command value.
[0040]
The disk device of the present invention includes any one of the circuit element driving devices described above and a lens driving device including an objective lens, a tracking coil, a focus coil, and a tilt coil.
[0041]
In a preferred embodiment, the disk device includes a conductive elastic body commonly connected to one end of each of the tracking coil, the focus coil, and the tilt coil, and each of the other ends of the tracking coil, the focus coil, and the tilt coil. And three conductive elastic bodies connected to each other.
[0042]
The circuit element driving method of the present invention is a method of driving n (n is an integer of 2 or more) circuit elements having two terminals based on n first command values. generating n drive voltages that vary based on n first command values and one common drive voltage that varies based on at least one of the n first command values, The common driving voltage is commonly applied to one end of each of the circuit elements, and the n driving voltages are applied to the other end of each of the n circuit elements.
[0043]
In a preferred embodiment, the common drive voltage is generated based on a maximum value and a minimum value of the n first command values.
[0044]
In a preferred embodiment, a difference between each voltage to be applied to the circuit element based on the first command value and each potential difference applied to both ends of the circuit element is substantially minimized. The n driving voltages and the common driving voltage are determined.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a first embodiment of the circuit element driving apparatus of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a circuit element driving circuit according to the present embodiment.
[0046]
The circuit element driving device of the present embodiment drives the spindle motor 1. The spindle motor 1 includes coils 2, 3 and 4 which are two-terminal circuit elements, respectively. One end of each coil is connected in common to the common terminal 5, and the other end is connected to the individual terminals 2a, 3a and 4a, respectively. The common terminal 5 and the individual terminals 2a, 3a and 4a are drawn from the spindle motor 1. That is, four terminals are drawn out for three coils.
[0047]
The circuit element driving apparatus according to the present embodiment includes a driving unit 6 and a control unit 7, and a voltage command value u that is a first command value. ₁ , U ₂ And u _Three And a voltage V which is a drive voltage applied to the common terminal 5 and the individual terminals 2a, 3a and 4a. _com , V ₁ , V ₂ And V _Three Is output.
[0048]
Voltage command value u ₁ , U ₂ And u _Three Contains information on the voltage to be applied to the coils 2, 3 and 4. The control unit 7 generates a voltage command value u ₁ , U ₂ And u _Three And performs a predetermined calculation based on these voltage command values, and based on the result, the common command value α and the correction command value r, which are the second command values, ₁ , R ₂ And r _Three Is generated. Then, the drive unit 6 determines that the common command value α, the correction command value r ₁ , R ₂ And r _Three In accordance with these command values, the voltage V _com , V ₁ , V ₂ And V _Three Is applied to the common terminal 5 and the individual terminals 2a, 3a and 4a.
[0049]
Within a predetermined range of possible ranges of the second command value, the drive voltage is proportional to the corresponding second command value. For example, it is assumed that the second command value can take a value in the range of −1.0 to +1.0, and the range in which the drive voltage is proportional is in the range of −0.5 to +0.5. Further, the range in which the drive voltage is proportional is made to correspond so that the drive voltage ranges from the minimum value of the power supply voltage applied to the drive unit 6 to the maximum value of the power supply voltage. In this case, the correction command value r ₁ When V is 0, voltage V ₁ Outputs half the power supply voltage. Specifically, when the power source is a single power source having a value from 0V to + 5V, the correction command value r ₁ Is 0, the voltage V ₁ Becomes 2.5V.
[0050]
The drive unit 6 cannot output a voltage exceeding the range of the power supply voltage, and the voltage range that the drive unit 6 can output is restricted by the voltage range of the power supply. Therefore, the correction command value r ₁ Is +0.5 or more, the maximum value of the power supply voltage +5 V is output. Conversely, the correction command value r ₁ Is less than −0.5, the minimum value of the power supply voltage is 0V. That is, the correction command value r ₁ When the absolute value of exceeds 0.5, the output voltage is saturated. Correction command value r ₁ And voltage V ₁ However, the relationship between the other second command value and the drive voltage is the same.
[0051]
In the following description, k is an integer from 1 to 3 indicating the number of the circuit element, and each command value is represented by a symbol k. For example, the voltage command value which is the first command value is u _k And the three command values u ₁ , U ₂ And u _Three Indicates. Similarly, the second command value and the drive voltage are set to the command value r. _k And voltage V _k It expresses.
[0052]
Below, the structure of the control part 7 is demonstrated. As shown in FIG. 1, the control unit 7 includes a maximum value detection unit 8, a minimum value detection unit 9, an inversion average unit 10, and addition units 11, 12, and 13. The maximum value detection unit 8 detects the voltage command value u _k The maximum value u _max Is detected. The minimum value detection unit 9 is configured to output a voltage command value u _k Minimum value u _min Is detected. Maximum value u detected _max And the minimum value u _min Is input to the inverting average unit 10. The reversal averaging unit 10 calculates the maximum value u _max And the minimum value u _min And a value obtained by inverting the sign of the average value is output as a common command value α. That is, the common command value α calculated by (Equation 3) is output.
[0053]
[Equation 3]

[0054]
The adder 11, adder 12, and adder 13 each have a voltage command value u ₁ , U ₂ And u _Three Is added to the common command value α, and the correction command value r ₁ , R ₂ And r _Three Is output. That is, the adding unit 11, the adding unit 12, and the adding unit 13 calculate the correction command value r calculated by (Expression 4) _k Is output.
[0055]
[Expression 4]

[0056]
In the conventional circuit element driving device, a voltage fixed at the midpoint value of the power supply voltage is applied to the common terminal. That is, in the prior art, the voltage applied to the common terminal does not change. On the other hand, in the circuit element driving device of the present invention, the common terminal 5 is actively driven by applying a varying voltage to the common terminal 5, and the control method of the common terminal 5 has one feature. The operation of the circuit element driving apparatus configured as described above will be described more specifically. In the following example, consider a case in which each coil of the spindle motor 1 is driven by a sine wave.
[0057]
FIG. 2 shows the first command value received by the control unit 7 of the circuit element driving device and the second command value to be output. In FIG. 2, the horizontal axis indicates the passage of time and is normalized so that one cycle of motor driving is 1. The vertical axis is the voltage command value u _k , Correction command value r _k The size of the common command value α is also normalized in the same manner. Voltage command value u ₁ Is a sine wave with a maximum amplitude of 0.58. Voltage command value u ₂ Is the voltage command value u ₁ Is a sine wave with a time lag of 1/3. Voltage command value u _Three Is the voltage command value u ₂ Is a sine wave with a time lag of 1/3.
[0058]
As shown in FIG. 1, the maximum value calculator 8 and the minimum value calculator 9 ₁ , U ₂ And u _Three The maximum value u _max And the minimum value u _min Is output to the inverting average unit 10. The inversion average unit 10 outputs the common command value α obtained by (Equation 3). As shown in FIG. 2, the common command value α is equal to the voltage command value u. _k Is a triangular wave with a maximum amplitude of 0.14.
[0059]
The adders 11, 12 and 13 have a common command value α and a voltage command value u. _k And the correction command value r obtained by (Equation 4) _k Is output. As shown in FIG. 2, the correction command value r _k Becomes a substantially trapezoidal wave in which the peak of the sine wave is deformed. Correction command value r ₁ , R ₂ And r _Three Are offset from each other by 1/3 of the time, and the amplitude is within ± 0.5.
[0060]
The common command value α generated in this way and the correction command value r ₁ , R ₂ And r _Three Is input to the drive unit 6 shown in FIG. 1 and is a voltage V which is a drive voltage proportional to these command values. _com , V ₁ , V ₂ And V _Three Will occur. For example, the value of 5 times the command value shown in FIG. _com , V ₁ , V ₂ And V _Three As output from the drive unit 6.
[0061]
Since the common command value α takes a value in the range of −0.14 to +0.14, the voltage V _com Takes a value in the range of -0.7V to + 0.7V. Further, the correction command value r ₁ , R ₂ And r _Three Takes a value from -0.5V to + 0.5V, so the voltage V ₁ , V ₂ And V _Three Takes a value in the range of -2.5V to + 2.5V. These values are all less than or equal to the midpoint value of the power supply voltage.
[0062]
As shown in FIG. 1, the voltages applied to the coils 2, 3 and 4 are the potential difference between the common terminal 5 and the individual terminal 2a, the potential difference between the common terminal 5 and the individual terminal 3a, and the common terminal 5 and the individual terminal 4a. And the potential difference. As shown in FIG. 2, the voltage applied to the coils 2, 3 and 4 is maximized because the common command value α is −0.14 and the correction command value r ₁ Is 0.44. At this time, the voltage V _com And V ₁ Becomes −0.7 V and 2.2 V, and a voltage of 2.9 V is applied to the coil 2. For this reason, a sine wave having an amplitude of 2.9 V is applied to the coil 2 as time elapses. That is, the maximum voltage and the minimum voltage applied to the coil 2 are + 2.9V and -2.9V, respectively. Similarly, a voltage of −2.9 V to +2.9 V is applied to both ends of the coils 3 and 4.
[0063]
In the conventional driving in which the common terminal 5 is fixed at the midpoint of the power supply voltage, as described in the related art, the maximum voltage is limited to 2.5 V, but according to the present embodiment, A voltage of 2.9 V can be applied, and the voltage that can be applied can be increased by 16%. This is because, as shown in FIG. 2, the common command value α does not take a constant value but fluctuates. That is, the voltage V based on the common command value α _com Is a variable value, and the common terminal 5 has a variable voltage V _com This is because is applied. Even if the voltage applied to the individual terminals 2a, 3a and 4a cannot take a value equal to or higher than the midpoint value of the power supply voltage, a voltage having a sign opposite to that of the individual terminal 2a is applied to the common terminal 5. Thus, a voltage equal to or higher than the midpoint value of the power supply voltage can be applied to the coils 2, 3 and 4 which are circuit elements.
[0064]
That is, the coils 2, 3, and 4 have the voltage command value u _k The voltage V varies based on ₁ , V ₂ And V _Three And the voltage command value u _k The voltage V varies based on _com The voltage V _com Is applied to the common terminal 5 commonly connected to one ends of the coils 2, 3 and 4, and the voltage V ₁ , V ₂ And V _Three Is applied to the individual terminals 2a, 3a and 4a, which are the other ends of the coils 2, 3 and 4, respectively. In this way, by connecting one end of each coil to the common terminal 5 in common, the number of terminals and wires to be connected to the three coils can be reduced. In addition, as described above, the voltage applied to the common terminal 5 is also changed to drive the coils 2, 3, and 4, so that the maximum value of the voltage applied to each coil can be prevented from being reduced.
[0065]
In the present embodiment, the voltage command value u ₁ , U ₂ And u _Three Is shifted by 1/3 period, but the voltage command value u ₁ , U ₂ And u _Three If the phases are in phase, the maximum voltage that can be applied to each coil can be 5V.
[0066]
Further, when the waveform of the command value for driving the circuit element is periodic, such as when driving the coil of the spindle motor, the waveform of the common command value α is also periodic. The common command value α is a voltage command value u. _k Is proportional to the amplitude of. Therefore, the common command value α for one cycle is recorded in the memory, and the voltage command value u _k If the value is called from the memory according to this, the calculation is not necessary. The time and power consumption required for calculation can be reduced.
[0067]
In the present embodiment, the drive unit 6 and the control unit 7 and the components such as the maximum value detection unit 8 included therein are known electronic circuits using electronic components, as is apparent from the above description. You may comprise by. The functions described above may be realized by using a microcomputer or DSP and performing signal processing by software.
[0068]
(Second Embodiment)
A second embodiment of the circuit element driving apparatus of the present invention will be described below. In the present embodiment, a disk device having a lens driving device and a circuit element driving device that controls the lens driving device will be described. FIG. 3 shows the lens driving unit 20 of the lens driving device. The lens driving unit 20 includes a lens 19, a tracking coil 21, a focus coil 22, and a tilt coil 23. The lens 19 is held by the lens holder 16, and the tracking coil 21, the focus coil 22 and the tilt coil 23 are fixed to the lens holder 16. The tracking coil 21 actually includes four coils connected in series, and the focus coil 22 includes two coils connected in series.
[0069]
One end of each of these three types of coils is commonly connected to the conductive elastic body 17a. The other ends of the tracking coil 21, the focus coil 22, and the tilt coil 23 are connected to conductive elastic bodies 17b, 17c, and 17d, respectively. The conductive elastic bodies 17a, 17b, 17c and 17d supply electric power to these coils and elastically support the lens driving unit 20. In the present embodiment, a linear conductive elastic body is used, but a conductive leaf spring, a spring having another shape, or a conductive elastic body other than the spring may be used.
[0070]
The lens driving unit 20 is inserted and held in the space 18B of the magnetic circuit 18. When current flows through the three types of coils via the conductive elastic bodies 17b, 17c, and 17d, the lens driving unit 20 is caused by repulsion or attraction between the magnetic force generated in the three types of coils and the magnet provided in the magnetic circuit 18. Move in a predetermined direction. Specifically, when a current is passed through the tracking coil 21, the lens driving unit 20 moves in the direction of the arrow 19A. Further, when a current is passed through the focus coil 22 and the tilt coil 23, the lens driving unit 20 moves in the directions of arrows 19B and 19C, respectively. Such a lens driving device is disclosed in, for example, Japanese Patent Laid-Open No. 7-65397.
[0071]
FIG. 4 shows a circuit element driving device for driving the lens driving unit 20 shown in FIG. In FIG. 4, the conductive spring 17a commonly connected to the tracking coil 21, the focus coil 22 and the tilt coil 23 of the lens driving unit 20 is connected to the common terminal 24, and the conductive springs 17b, 17c and 17d are individual terminals. 21a, 22a and 23a are connected.
[0072]
The circuit element driving apparatus of the present embodiment includes a drive unit 6 and a linear matrix calculation unit 25 as a control unit, and a voltage command value u that is a first command value. ₁ , U ₂ And u _Three And a voltage V that is a drive voltage applied to the common terminal 24 and the individual terminals 21a, 22a, and 23a. _com , V ₁ , V ₂ And V _Three Is output.
[0073]
Voltage command value u ₁ , U ₂ And u _Three Includes information on voltages to be applied to the tracking coil 21, the focus coil 22, and the tilt coil 23. As in the first embodiment, the linear matrix calculation unit 25 generates the voltage command value u. ₁ , U ₂ And u _Three And performs a predetermined calculation based on these voltage command values, and based on the result, the common command value α and the correction command value r, which are the second command values, ₁ , R ₂ And r _Three Is generated. Then, the drive unit 6 determines that the common command value α, the correction command value r ₁ , R ₂ And r _Three In accordance with these command values, the voltage V _com , V ₁ , V ₂ And V _Three Is applied to the common terminal 24 and the individual terminals 21a, 22a and 23a.
[0074]
The voltage range that can be output by the drive unit 6 is limited by the voltage range of the power supply, and the common command value α and the correction command value r ₁ , R ₂ And r _Three When the absolute value of exceeds 0.5, the output voltage is saturated. When the output voltage does not saturate, the voltage applied to each of the coils 21, 22 and 23 is determined by the following equation (Equation 5).
[0075]
[Equation 5]

[0076]
Here, E is a constant determined by the voltage of the power source. In the case of a one-side power source that can take from 0V to + 5V, E = 5V. If the power supply is a double-sided power supply that can take from -5V to + 5V, E = 10V. The left side of (Formula 5) is a voltage applied to both ends of the three coils. The matrix of (Equation 5) is determined by the wiring between the three coils and the drive unit 6. The wiring is wired so that voltage application to the three coils can be controlled independently. A matrix determined by the wiring is represented by a matrix A as shown in (Expression 6).
[0077]
[Formula 6]

[0078]
Next, the configuration of the linear matrix calculation unit 25 will be described. The linear matrix calculation unit 25 calculates the voltage command value u ₁ , U ₂ , U _Three Based on the common command value α and the correction command value r ₁ , R ₂ , R _Three Is output. Specifically, as represented by (Equation 7), the linear matrix calculation unit 25 multiplies three input signals by a matrix B having a size of 4 × 3 to generate four output signals.
[0079]
[Expression 7]

[0080]
The calculation by (Equation 7) is realized by multipliers 28a to 28l and adders 29a to 29d as shown in FIG. For example, the common command value α is supplied to the multipliers 28a, 28e and 28i as a voltage command value u. ₁ , U ₂ And u _Three And weight b ₁₁ , B ₁₂ , B ₁₃ And the obtained values are added together by the adding unit 29a.
[0081]
Next, the 12 parameters (b ₁₁ ~ B ₁₃ , B _{twenty one} ~ B _{twenty three} , B ₃₁ ~ B ₃₃ , B ₄₁ ~ B ₄₃ ) Will be described. FIG. 5 is a block diagram showing the configuration of the parameter determination unit that determines the parameters of the linear matrix calculation unit 25 described above. 5, the configuration of the linear matrix calculation unit 25 is the same as that in FIG. 4. The parameter determination unit includes a weight calculation unit 26 and a generalized inverse matrix calculation unit 27. The weight calculation unit 26 calculates the voltage command value u ₁ , U ₂ And u _Three And the importance of the voltage command value is calculated based on the past voltage command value. If the past voltage command value has a large amplitude, the voltage command value is considered as an important signal in the system. As a scale for determining the importance of the voltage command value, a norm value related to time is adopted in the present embodiment. For example, the ∞ norm of the voltage command value as given by (Equation 8) is used as a measure of the importance of the signal. The ∞ norm corresponds to the maximum value of the signal amplitude.
[0082]
[Equation 8]

[0083]
However, k = 1, 2, and 3. The weight calculation unit 26 calculates the weight w obtained by (Equation 8). _k Is output to the generalized inverse matrix calculation unit 27. The generalized inverse matrix calculation unit 27 calculates the weight w _k The matrix B of the linear matrix calculation unit 25 is calculated as follows using the weight matrix R having as parameters. First, the weight matrix R is defined by (Equation 9).
[0084]
[Equation 9]

[0085]
Next, the calculation according to (Equation 10) is performed using the weight matrix R, and the matrix B is calculated.
[0086]
[Expression 10]

[0087]
Here, T on the right shoulder of the matrix A represents transposition. As described above, the matrix B generated by the generalized inverse matrix calculation unit 27 is used in the linear matrix calculation unit 25. The value of the matrix B used in the linear matrix calculation unit 25 is updated as appropriate.
[0088]
The matrix B given by the above (Equation 10) minimizes the norm of the command value input to the drive unit 6. That is, the evaluation function J given by (Equation 11) is minimized.
[0089]
[Expression 11]

[0090]
As for the weight of the common command value α, the designer appropriately determines a standard value. If the variable J of the evaluation function (Equation 11) is small, the command value output to the drive unit 6 is small, and the output saturation is as small as possible.
[0091]
That is, the evaluation function (Equation 11) is an evaluation function for determining the magnitude of the voltage output from the drive unit 6, and when the evaluation function (Equation 11) is minimized, the voltage command value u _k Accordingly, the difference between the voltage to be generated in accordance with the driving voltage output from the driving unit 6 is substantially minimized.
[0092]
The operation of the circuit element driving apparatus configured as described above will be described. As an example of operation, consider a case in which the lens driving unit 20 is driven so that a current is supplied mainly to the tracking coil 21 and a current supplied to the focus coil 22 and the tilt coil 23 is reduced. Such control is suitable for the case where information is stably recorded and / or reproduced using a disc having a small eccentricity but a large eccentricity. This is because less current flows to the focus coil 22 but more current to flow to the tracking coil 21 is required.
[0093]
Specifically, the voltage command value u _k Consider the case where is (Equation 12).
[0094]
[Expression 12]

[0095]
In this case, the weighting coefficient is determined as the value of (Equation 13) from the maximum amplitude value of (Equation 12).
[0096]
[Formula 13]

[0097]
When (Equation 10) is calculated using the above values, the matrix B that is the output of the generalized inverse matrix calculation unit 27 becomes (Equation 14).
[0098]
[Expression 14]

[0099]
Subsequently, the voltage command value u in (Equation 12) _k The operation of the circuit element driving apparatus when given is given. FIG. 6A shows the waveform of the voltage command value input to the circuit element driving device of the present embodiment. FIG. 6B shows the voltage command value u. _k The linear matrix unit 25 performs an operation based on the common command value α and the correction command value r that are output based on the operation result. _k The waveform is shown. Common calculation command value α and correction command value r _k Based on the voltage V _com And voltage V _k Is output. FIG. 6C shows the potential difference V applied to the coils 21, 22, and 23. _k -V _com The waveform is shown. In these drawings, the horizontal axis indicates time, and the vertical axis indicates voltage.
[0100]
As shown in FIG. 6 (a), the voltage command value u ₁ Is a sine wave with an amplitude of 0.8, and the absolute value of the maximum value exceeds 0.5. However, as shown in FIG. 6B, the correction command value r _k And the absolute value of the common command value α does not always exceed 0.5, and is within the range of ± 0.5. That is, the output does not saturate in the drive unit 6.
This is because the matrix B is determined so that the variable J of the evaluation function given by (Equation 14) is minimized in order to make output saturation less likely.
[0101]
Each correction command value r _k In order not to reduce the maximum voltage that can be applied to the coils 21, 22, 23 while preventing the absolute value of the maximum value of the common value 24 from exceeding 0.5, the common terminal 24 commonly connected to the coils 21, 22, 23 is used. Voltage V applied to _com Is changing. As shown in FIG. 6B, the voltage V _com The common command value α for generating is approximately the correction command value r ₁ The waveform with the polarity reversed is shown. For this reason, the actual potential difference applied to both ends of the coil 21 is ± 4 V as shown in FIG.
[0102]
Voltage command value u ₂ And u _Three As will be understood from FIGS. 6A and 6B, the correction command value r ₂ And r _Three Is the voltage command value u ₂ And u _Three And the phase is different, and the correction command value r ₂ And r _Three The absolute value of the maximum value is the voltage command value u ₂ And u _Three Is bigger than. However, as shown in FIG. 6C, the voltage V applied to both ends of the coil 22 and the coil 23. ₂ -V _com And V _Three -V _com Is the voltage command value u ₂ And u _Three And the voltage command value u ₂ And u _Three The value is almost proportional to
[0103]
As described above, in the conventional driving method in which the common terminal is fixed at the midpoint of the power supply voltage, the maximum amplitude cannot be 2.5 V or more. However, according to the present embodiment, a voltage of 4 V can be applied. It becomes possible.
[0104]
In the above embodiment, the importance of the voltage command value is calculated based on the past voltage command value, and the values of the matrix B are changed. When such a matrix is used, the compatibility between the input voltage command value and the potential difference between the voltages applied to both ends of the coils 21, 22, and 23 is increased. Weight w _k The ∞ norm is used as the above, but the use of other norms such as Euclidean norm (root mean square of signal) has the same effect. Further, although the importance of the voltage command value has been described only for the magnitude of the past voltage command value, a weighting factor intended by the designer may be used.
[0105]
A constant can also be used as the matrix B. For example, when the weight matrix R is a unit matrix, the matrix B has a form with good symmetry as shown in (Expression 15).
[0106]
[Expression 15]

[0107]
When the symmetry of the matrix B is good, the configuration of the linear matrix calculation unit that is a control unit can be simplified using the linearity of the calculation. FIG. 7 is a block diagram showing a modification of the present embodiment. The linear matrix calculation unit 25 includes addition units 29e to 29h and a multiplication unit 28m. As shown in FIG. 7, the adding unit 29e is configured to output the voltage command value u ₁ , U ₂ , U _Three Is added to the multiplication unit 28m. The multiplier 28m multiplies this value by -1/4 and outputs the result as a common command value α.
[0108]
In the adders 29f, 29g and 29h, the common command value α and the voltage command value u ₁ , U ₂ , U _Three And the correction command value r ₁ , R ₂ , R _Three Output as. According to the linear matrix calculation unit 25, the number of multiplication units can be reduced by using symmetry, so that the calculation speed can be improved and the power consumption can be reduced.
[0109]
In the present embodiment, the drive unit 6, the linear matrix calculation unit 25, the weight calculation unit 26, the generalized inverse matrix calculation unit 27, and the like are known analog circuits using electronic components as is apparent from the above description. Can be configured. Alternatively, these may be processed by software using a microcomputer or DSP to realize the functions described above.
[0110]
(Third embodiment)
Similarly to the second embodiment, the circuit element driving device of this embodiment also drives a lens driving device such as an optical disk drive device. The circuit element driving device performs PWM control.
[0111]
FIG. 8 is a block diagram showing the circuit element driving apparatus of the present embodiment. Similar to the second embodiment, the lens driving unit 20 includes a tracking coil 21, a focus coil 22, and a tilt coil 23. As described in detail in the second embodiment, one end of each of the three coils is commonly connected to one conductive elastic body, and the other end of each coil is connected to each conductive elastic body. Yes. The conductive elastic bodies connected in common and the conductive elastic bodies connected to the tracking coil 21, the focus coil 22, and the tilt coil 23 are connected to the common terminal 24, the individual terminals 21a, 22a, and 23a, respectively. .
[0112]
The circuit element driving apparatus according to the present embodiment includes a control unit 36 and a driving unit 34.
[0113]
As in the first and second embodiments, the control unit 36 determines a current command value u that is a command to the tracking coil 21, the focus coil 22, and the tilt coil 23. ₁ , U ₂ , U _Three And the common command value α and the correction command value r ₁ , R ₂ , R _Three Is output. A specific circuit configuration of the control unit 36 will be described in detail later.
[0114]
Common command value α and correction command value r ₁ , R ₂ , R _Three The drive unit 34 that receives the signal includes a duty variable unit 35 and a switching drive unit 30. The duty variable unit 35 of the drive unit 34 receives the common command value α and the correction command value r. ₁ , R ₂ , R _Three And switching signals Yc, Y1, Y2, and Y3 are generated.
[0115]
The duty variable unit 35 includes a reference signal generator 37 that outputs a triangular wave or a sawtooth wave, and comparators 38, 39, 40, and 41. The comparators 38, 39, 40, and 41 include a reference signal rt output from the reference signal generator 37, a common command value α, and a correction command value r. ₁ , R ₂ , R _Three And the results are output as switching signals Yc, Y1, Y2, and Y3, respectively. That is, the common command value α and the correction command value r ₁ , R ₂ , R _Three The switching signals Yc, Y1, Y2, and Y3 having the duty ratio based on are generated.
[0116]
The switching drive unit 30 receives the switching signals Yc, Y1, Y2, and Y3, and the voltage waveform V corresponding to the switching signals Yc, Y1, Y2, and Y3. _com , V ₁ , V ₂ , V _Three Are output independently. For this purpose, the switching drive unit 30 includes four independent circuits.
[0117]
Each circuit includes two transistors, two diodes, and one signal inverting element. For example, the switching signal Yc is received and the voltage V _com Is output to the common terminal 24, the switching signal Yc is input to the transistor Q1 and the inverting element 31, and the output of the inverting element 31 is further input to the transistor Q2. The collector of the transistor Q1 is connected to VDD which is the maximum value of the power supply voltage, and the emitter of the transistor Q2 is connected to GND which is the minimum value of the power supply voltage. The emitter of the transistor Q1 and the collector of the transistor Q2 are connected to each other so that the voltage V _com Is output as The diode D1 and the diode D2 are connected between the collector and the emitter of the transistor Q1 and the transistor Q2, respectively, and are used as elements for protecting the transistor from overvoltage.
[0118]
Receives switching signals Y1, Y2 and Y3 and voltage V ₁ , V ₂ , V _Three Are also connected as described above to signal inversion elements 32, 33, 34, transistors Q3 and Q4, Q5 and Q6, Q7 and Q8, and diodes D3 and D4, D5 and D6, D7 and D8, respectively. ing.
[0119]
Next, the configuration of the control unit 36 will be described. As shown in FIG. 7, the control unit 36 includes a common command value calculation unit 42 and addition units 43, 44, 45. Current command value u input to the control unit 36 ₁ Is input to the common command value calculator 42. The common command value calculation unit 42 calculates the current command value u ₁ Is output based on the common command value α. The common command value α is output to the comparator 38 of the duty variable unit 35 as it is. On the other hand, the adding unit 43 is configured to supply a current command value u ₁ And the common command value α are added to obtain a correction command value r ₁ Is output. Similarly, the adding unit 44 determines the current command value u. ₂ And the common command value α are added to obtain a correction command value r ₂ Is output. Further, the adding unit 45 is configured to supply a current command value u. _Three And the common command value α are added to obtain a correction command value r _Three Is output.
[0120]
In the present embodiment, one of the current command values u ₁ Is input to the common command value calculation unit 42 because it is assumed that the tracking coil 21 is driven more preferentially than the focus coil 22 and the tilt coil 23. For example, there are many cases where the disk is eccentric and a large amount of driving force is required for tracking control. Details will be described in the operation description.
[0121]
As an example of the common command value calculation unit 42, for example, the circuit shown in FIG. 9 is used in this embodiment. As shown in FIG. 9, the common command value calculation unit 42 includes operational amplifiers 46, 47 and 48.
[0122]
The operational amplifier 46 forms an inverting amplifier circuit in cooperation with the resistors R1 and R2. Zener diode ZD1 and Zener diode ZD2 connected in series are connected in parallel to resistor R2. Input current command value u ₁ The operational amplifier 46 outputs an intermediate calculated value β according to the magnitude of. The operational amplifier 47 is an inverting addition circuit. Current command value u input through resistor R4 ₁ And the signal β input through the resistor R3 are output as a common command value α with a gain determined by the ratio of the resistor R3 and the resistors R4 and R5.
[0123]
In the above configuration, the resistors R1, R2, R3, R4, and R5 all have approximately the same resistance value. The operational amplifier 48 is a buffer, and a current command value u ₁ And an output shortage s1 that is a value obtained by adding the intermediate calculation value β. The output shortage amount s1 is a value obtained by calculating how much the output of the tracking coil 21 is insufficient when the common command value α is zero. The output shortage amount s1 will be described later. The common command value α is a value obtained by inverting the output shortage s1.
ing.
[0124]
The operation of the circuit element driving apparatus configured as described above will be described. FIG. 10 shows the current command value u in the common command value calculation unit 42 of the control unit 36. ₁ And the intermediate calculated value β. In FIG. 10, the horizontal axis and the vertical axis indicate the current command value u. ₁ And the intermediate calculated value β, respectively, and these values are normalized.
[0125]
The operational amplifier 46 inputs the value u of the ratio of the resistance R1 and the resistance R2. ₁ Is inverted and amplified. However, voltage feedback is limited by the Zener diodes ZD1 and ZD2 connected in parallel to the resistor R2, and therefore the output is limited by an appropriate voltage. In the present embodiment, appropriate Zener diodes ZD1 and ZD2 are selected so as to limit the output with an absolute value of 0.5.
[0126]
Current command value u ₁ When the absolute value of is less than 0.5, the current command value u ₁ And the inverted value is output as the intermediate calculation value β. On the other hand, if the absolute value of the current command value u1 is greater than 0.5, the sign of the current command value u1 is inverted, and a signal having an absolute value of 0.5 is output as the intermediate calculation value β.
[0127]
The purpose of creating an intermediate calculation value β that saturates at an absolute value of 0.5 is to provide a voltage saturation model of the drive unit 34 (duty variable unit 35 and switching drive unit 30) inside the control unit 36 to obtain information on output saturation. Because. Current command value u ₁ Is output to the drive unit as it is, the current command value u ₁ If the absolute value of is not more than 0.5, output saturation does not occur in the drive unit 34. However, when the absolute value exceeds 0.5, the output of the drive unit 34 is saturated and the output is insufficient. In the present embodiment, the output shortage amount s1 is determined from the intermediate calculated value β and the current command value u. ₁ It is obtained as an addition value of.
[0128]
FIG. 11 shows the current command value u ₁ And the output shortage amount s1. In FIG. 11, the horizontal axis indicates the current command value u. ₁ The vertical axis indicates the output shortage s1. All of these values represent normalized voltages. As is apparent from the figure, the current command value u ₁ Is in the range of −0.5 to 0.5, the output shortage amount s1 is zero. In other ranges, the output shortage amount s1 is equal to the current command value u. ₁ It increases in proportion to.
[0129]
By generating the common command value α using the output shortage amount s1 thus obtained and controlling the voltage at the common terminal 24, the shortage of the drive voltage of the tracking coil 21 is resolved. Output V of common terminal 24 by output shortage s1 _com Therefore, the common command value α is set as the inverted value of the output shortage. Specifically, the output of the operational amplifier 47 is used as the common command value α. 12 shows the current command value u in FIG. ₁ And the common command value α. In FIG. 12, the horizontal axis represents the current command value u. ₁ The vertical axis represents the common command value α. All of these values represent normalized voltages.
[0130]
When the output shortage amount s1 of the tracking coil 21 is corrected, the correction is made using the common terminal 24. Therefore, the voltage applied to the common terminal 24 also affects the driving of the other focus coils 22 and tilt coils 23. give. In order to correct this influence, the common command value α output from the common command value calculation unit 42 is input to the addition unit 44 and the addition unit 45. The adder 44 and the adder 45 are configured to generate a current command value u ₂ , U _Three , And the sum of these command value and common command value α is corrected to the command value r ₂ , Correction command value r _Three Respectively. Since the common command value α is an inverted value of the output shortage amount s1, the voltage corresponding to the output shortage amount s1 is corrected by this addition. ₁ , Correction command value r ₂ , Correction command value r _Three The common command value α applied to the common terminal 24 is canceled.
[0131]
The common command value α is also input to the adding unit 43, and the adding unit 43 receives the current command value u. ₁ Is added to the common command value α. Current command value u ₁ When the value exceeds 0.5, the common command value α has an inverted value of the output shortage amount s1. ₁ Is greater than 0.5, the correction command value r ₁ Continues to output 0.5.
[0132]
Next, the voltage applied to both ends of the tracking coil 21 will be described. FIG. 13 (a) shows the current command value u. ₁ , The time change of the reference signal rt and the common command value α is shown. In FIG. 13A, the horizontal axis represents time, and the vertical axis represents normalized voltage. The reference signal rt is a sawtooth wave generated in the reference signal generator 37 of the duty variable unit 35 and changing from −0.5 V to +0.5 V at a constant speed during one period. Since the amplitude of the sawtooth wave is 0.5, the correction command value r _k When the absolute value of exceeds 0.5, the portion exceeding the absolute value of 0.5 is ignored by comparison with the reference signal rt. That is, a large correction command value r exceeding 0.5 _k Even if is specified, the correction command value is regarded as 0.5, the switching command is not changed, and the coil drive is not affected.
[0133]
In FIG. 13A, the time on the horizontal axis is divided into a section T1, a section T2, and a section T3 with the period of the reference signal rt as a section. When the time changes in order of section T1, section T2, and section T3, current command value u ₁ Changes to -0.2, +0.2, and +0.8. In the section T1 and the section T2, the current command value u ₁ Is within ± 0.5, the common command value α is zero. On the other hand, in the section T3, the current command value u ₁ Is +0.8, the constant +0.5 is exceeded by 0.3. Accordingly, α is −0.3 from the input / output relationship of FIG.
[0134]
In the duty variable section 35, the reference signal rt, the common command value α, and the correction command value r ₁ Are compared in comparators 38 and 39, and switching signals Yc and Y1 are output based on the comparison result.
[0135]
FIGS. 13B and 13C show the voltage V output by the drive unit 30 based on the switching signals Yc and Y1. _com And V ₁ The waveforms are shown respectively. In each figure, the horizontal axis represents time, and the vertical axis represents voltage.
[0136]
First, referring to FIGS. 13A and 13B, the voltage V _com Will be explained. Since rt <α in the first half of the section T1, the switching signal Yc is at a high level. When the switching signal Yc is at a high level, the transistor Q1 is turned on and the transistor Q2 is turned off. At this time, the voltage V of the common terminal 24 _com Is the maximum value VDD level of the power supply voltage. On the other hand, since rt> α in the second half of the section T1, the switching signal Yc is at a low level. When the switching signal Yc is at a low level, the transistor Q1 is turned off and the transistor Q2 is turned on. Therefore, the voltage V of the common terminal 24 _com Becomes the minimum value GND level of the power supply voltage. The same operation is performed in the section T2. As a result, V at the midpoint of the section T1 and the midpoint of the section T2. _com Is switched from VDD to GND. Voltage V _com Is switched when the magnitude relationship between the duty command value α and the reference signal rt is switched. Similarly in the section T3, the voltage V from VDD to GND _com However, since α is −0.3, the switching point becomes earlier in the section T3.
[0137]
Next, referring to FIGS. 13A and 13C, the voltage V ₁ Will be explained. Voltage V _com Similarly to the current command value u in the section T1 ₁ Is −0.2, so the voltage V in the first half of the section T1 ₁ Switches from VDD to GND. In section T2, current command value u ₁ Is +0.2, so that the voltage V ₁ Switches from VDD to GND. In section T3, current command value u ₁ Is +0.8, so the current command value u ₁ And the correction command value r which is the sum of the common command value α ₁ Is 0.5 (+0.8 + (− 0.3)). At this time, the voltage V ₁ Switching does not occur, so the voltage V ₁ Becomes VDD.
[0138]
FIG. 13 (d) shows the voltage V ₁ And voltage V _com And the voltage applied to both ends of the tracking coil 21 (V ₁ -V _com ). In the section T1, a voltage (−VDD) is applied to both ends of the tracking coil 21. In the section T2, the voltage (+ VDD) is applied to both ends of the tracking coil 21. In these sections T1 and T2, the time during which the voltage is applied is 20% of the section width.
Further, in the section T3, the applied voltage time is extended by the amount corrected by the common command value α (−0.3), so that the voltage (+ VDD) is applied in the time of 80% of the section width. Current command value u ₁ It is clear that the same operation is performed even when takes a value other than the above-described value, and the time taken at both ends of the tracking coil 21 is the current command value u. ₁ Is proportional to Therefore, if the cycle of the reference signal rt is sufficiently fast, the current command value u ₁ Current flows through the tracking coil 21.
[0139]
Next, driving of the focus coil 22 will be described. FIG. 14A shows the current command value u. ₂ , Reference signal rt and correction command value r ₂ The time change of is shown. In FIG. 14A, the horizontal axis represents time, and the vertical axis represents normalized voltage. The reference signal rt and the common command value α shown in FIG. 14A are the same as the reference signal rt and the common command value α shown in FIG. From the section T1 to the section T3, the current command value u ₂ Is constant +0.1. At this time, the correction command value r ₂ Since the common command value α is zero, the current command value u ₂ be equivalent to. On the other hand, since α = −0.3 in the section T3, the correction command value r ₂ Becomes −0.2 (+0.1 + (− 0.3)). In the duty variable unit 35, the reference signal rt and the correction command value r ₂ Are compared in the comparator 40, and the switching signal Y2 is output based on the comparison result.
[0140]
14 (b) and 14 (c) show the voltage V _com And voltage V ₂ FIG. 14D shows a voltage (V) applied to both ends of the focus coil 22. ₂ -V _com ) Shows the waveform. In each figure, the horizontal axis indicates time, and the vertical axis indicates voltage.
[0141]
As described with reference to FIGS. 13A, 13B, and 13C, in the sections T1 and T2, the current command value u ₂ And the voltage V based on the common command value α. ₂ And voltage V _com Therefore, the voltage (+ VDD) is applied to both ends of the focus coil 22 for a time of 10% of the section width. In section T3, current command value u ₂ Is equal to +0.1, which is the same as the intervals T1 and T2, the common command value α is −0.3, so that the correction command value r ₂ Becomes -0.2. That is, the voltage V that changes depending on the common command value α. _com Correction command value r to compensate for the amount of change in ₂ Adjust. For this reason, the voltage (V ₂ -V _com ) Is the same value as the intervals T1 and T2.
[0142]
However, since the common command value is −0.3 in the section T3, the current command value u ₂ There is a limit to the current that can be output. Specifically, the maximum time during which the voltage (+ VDD) can be applied to the focus coil 22 is up to 20% of the section width. Further, the maximum time during which the voltage (−VDD) can be applied is up to 80% of the section width. The tilt coil 23 is also driven in the same manner as the focus coil 22.
[0143]
As is clear from the above description, the voltage V applied to the common terminal 24 _com Is generally fixed at the midpoint VDD / 2 of the power supply voltage. In the present embodiment, the voltage V _com It differs greatly from the prior art in that it is applied to. Voltage V _com By switching alternately, there is an advantage that the instantaneous maximum voltage that can be applied to one circuit element can be ± VDD. Also, the voltage V _com The switching duty of the current command value u is not fixed to 50%. ₁ By correcting the common command value α using the output shortage amount s1 obtained from the above, the time ratio for applying the voltage to the tracking coil 21 can be increased to 50% or more.
[0144]
According to the present embodiment, a current is mainly applied to the tracking coil 21, and the current that is applied to the focus coil 22 and the tilt coil 23 is partially limited. For this reason, although the current to the focus coil 22 may be small, the present embodiment is suitable when using a disk that requires a large amount of current to flow through the tracking coil 21 and that has a small surface deflection and a large amount of eccentricity.
[0145]
When information is recorded / reproduced using a disk with a lot of surface blur and little eccentricity, the current to the focus coil 22 is increased and the current to the tracking coil 21 is decreased. For this purpose, in the above-described embodiment, the control method of the tracking coil 21 and the control method of the focus coil 22 are interchanged, so that information can be recorded / reproduced stably.
[0146]
Below, the modification of this embodiment is demonstrated. FIG. 15 is a block diagram illustrating a control unit 56 that is a modification of the control unit 36 of the present embodiment. The control unit 56 is different in the configuration of the control unit 36 and the common command value calculation unit 52 shown in FIG. The adding unit 43, the adding unit 44, and the adding unit 45 are the same as those used in the control unit 36 of FIG.
[0147]
As shown in FIG. 15, the common command value calculation unit 52 includes three output shortage calculation units 50, each of which has a current command value u. _k Input and output shortage s _k Is output. Here, k is an integer of k = 1, 2, 3. Output shortage amount s _k Are input to the maximum value detection unit 8 and the minimum value detection unit 9. The maximum value detection unit 8 and the minimum value detection unit 9 each have a maximum value S of the output shortage. _max And the minimum value S of the output shortage _min (Maximum amount of shortage with negative output) is output. Maximum value S _max And the minimum value S _min Are added by the inverting adder 49, and output with the sign inverted.
[0148]
The operation of the common command value calculation unit 42 operates in the same manner as the common command value calculation unit 42 shown in FIG. 8, but the output shortage amount is not considered only for the tracking coil 21, but is obtained for all coils and output. Deficiency _k Is different from the common command value calculation unit 42 shown in FIG. 8 in that the maximum value and the minimum value are detected by the maximum value detection unit 8 and the minimum value detection unit 9.
[0149]
In the present embodiment, the case where three coils are driven has been described. However, the present invention can also be suitably applied to a case where four or more coils are driven. In order to drive the n coils, (n + 1) drive circuits may be prepared. Moreover, since the circuit per coil can be simplified, implementation of the present invention is easy.
[0150]
In the above embodiment, the drive unit 34 and the control unit 36 are realized by arithmetic processing using a known analog circuit. However, a microcomputer or a DSP (Digital Signal Processor) is used to perform the input by software timer processing. This can also be realized by outputting a signal obtained by periodically inverting the bit of the output port to the switching drive unit 30. In this case, the number of bits required to drive n coils or circuit elements is (n + 1).
[0151]
(Fourth embodiment)
A circuit element driving apparatus according to a fourth embodiment of the present invention will be described below.
[0152]
The circuit element driving apparatus of the present embodiment has the same configuration as the circuit element driving apparatus shown in FIG. 8, and the calculation method in the common command value calculation unit 42 is different. In this embodiment, the input command value u _k When the output is insufficient and the output shortage occurs, the common command value α is determined so that the output shortage ratio is not biased to a specific coil. A DSP is used for the calculation in this embodiment. In the following description, a procedure for calculating the common command value α will be described.
[0153]
First, in the following description, k is an integer representing a coil number. Voltage command value u _k Is given, and the common command value α is an unknown parameter obtained by calculation. Output shortage s _k Is defined by the following equation (Equation 16) including the common command value α.
[0154]
[Expression 16]

[0155]
Here, sgn (x) is a sign function defined by (Equation 1). q is a constant 0.5. Output shortage s _k Is negative, the k-th coil has a voltage command value u _k The output is deficient _k Is positive, the k-th coil is in an insufficient current drive state.
[0156]
Next, the output shortage s _k An evaluation function with the argument is defined by (Equation 17).
[0157]
[Expression 17]

[0158]
w _k Is a weighting factor, and the evaluation function J (α) is a weighting factor w _k Multiplied by _k The maximum value is output. Weighting factor w _k May be a constant that the designer has estimated in advance the degree of influence on the system, and the voltage command value u _k It may be a value obtained from the norm related to the time. For example, weighting factor w _k The voltage command value u _k If the reciprocal of the maximum amplitude of (w _k ・ S _k ) Represents a deficiency ratio in the maximum amplitude of the voltage command value in the k-th coil. If the evaluation function defined by (Equation 17) is minimized, the shortage ratio in the maximum amplitude of the voltage command value in a specific coil does not increase significantly. That is, the shortage of drive voltage does not concentrate on a specific coil.
[0159]
Next, a procedure for obtaining the common command value α that minimizes the evaluation function defined by (Equation 17) will be described. First, an integer i and an integer j are set as coil numbers. Voltage command value u _i And the voltage command value u _i Voltage command value u with different sign _j Common command value candidate α _ij Is calculated using (Equation 2).
[0160]
Continued α _ij Α that minimizes the evaluation function defined by (Equation 17) is selected. The above is the procedure for obtaining the common command value α. The voltage command value has the same sign (sgn (u _i ) ・ Sgn (u _j ) = 1) is omitted in the calculation process in order to improve the calculation speed by omitting a step for obtaining a meaningless solution.
[0161]
Note that (Equation 2) is deeply related to the first embodiment, and is a calculation formula obtained by extending (Equation 3). For example, all w _k (Equation 2) is obtained when they are equal. That is, the calculation of the present embodiment takes into account the signal weight in the calculation of the first embodiment.
[0162]
Below, the example of the calculation in the common command value calculation part 42 of this embodiment is demonstrated. (Table 1) shows the voltage command value u. _k Amplitude, weighting factor w _k , Voltage command value u _k Indicates. Using the numerical values given by (Table 1) (w _k ・ S _k FIG. 16 shows the result of calculating). FIG. 16 shows the (w _k ・ S _k ) And the common command value α. In FIG. 16, the vertical axis represents (w _k ・ S _k The horizontal axis represents the common command value α.
[0163]
[Table 1]

[0164]
On the other hand, the candidate α of the common command value α using (Equation 2) _ij (Table 2). In Table 2, if the combination of (i, j) is (1, 2), (1, 3), (1, 4), u _i And u _j Are different from each other. Sought α _ij When the evaluation function is obtained for, the evaluation function J (α) is minimized when (i, j) = (1, 2). As is clear from FIG. 16, each (w _k ・ S _k If the point where the maximum value of) is minimum is searched, it is point Q1, which matches the calculation result. The obtained α = −0.035 is output as a common command value. This completes the calculation procedure.
[0165]
[Table 2]

[0166]
The effect of the value of the common command value α thus obtained is compared with the case where the common command value α is zero. (Table 3) is (w _k ・ S _k ) Is calculated for α = −0.035 and α = 0. When α = 0 without correction, the output shortage of the coil with k = 1 is (w1 · s1) = 0.33, and 33% of the amplitude 0.9 of the voltage command value is insufficient. Similarly, the output shortage of the coil with k = 2 is (w2 · s2) = 0.25, and the voltage command value u ₂ This is a 25% shortage with respect to an amplitude of 0.8.
[0167]
[Table 3]

[0168]
On the other hand, when α = −0.035, the output shortage of the coil of k = 1 and the coil of k = 2 is 0.29, and 29% of the amplitude of the voltage command value is insufficient. That is, by distributing the drive voltage of the coil with k = 1 from the other coils with k = 2 and k = 3, the shortage of the coil with k = 1 and k = 2 becomes approximately the same.
[0169]
In the above calculation, α is determined so as to minimize the evaluation function J (α) represented by (Equation 17). Next, an evaluation function that minimizes the sum of squares of the output shortage will be described. The sum of squares of the output shortage corresponds to the sum of the shortage energy, and when a plurality of coil drives are short of output at the same time, the total energy of the shortage of output is minimized to achieve stabilization. More specifically, the common command value α that minimizes the evaluation function of (Equation 19) expressed using the positive value function given by (Equation 18) is calculated.
[0170]
[Expression 18]

[0171]
[Equation 19]

[0172]
Here, m is an appropriate positive number, and m = 2. A case other than m = 2 will be described later. m is a parameter that can be appropriately determined by the designer.
[0173]
The calculation procedure of α that minimizes the evaluation function J shown in (Equation 19) is performed by searching. Since the search unit can use a known method, the description thereof is omitted here. The initial value α of the search ₀ If is selected using (Equation 17), the search starts from a point close to the solution, which is efficient. Further, since the solution often exists in the vicinity of α = 0, it is more efficient if the initial search direction is directed toward α = 0.
[0174]
The calculation result of the evaluation function defined by (Equation 19) will be described with reference to (Table 3) and FIG. FIG. 17 shows the relationship between the common command value α and the value of the evaluation function. In FIG. 17, the horizontal axis is the common command value α, and the vertical axis is the value of the evaluation function J (α). The black triangle mark is a line in which the evaluation function of (Equation 17) is plotted, and is the minimum at the point Q1. The white square mark “□” is a plot when m = 2 in the evaluation function of (Equation 19), and is the minimum at the point Q2. At the point Q2, the value of α is −0.009. If this α is output as a common command value, the system becomes more stable in the sense that the sum of the shortage of energy is minimized.
[0175]
Next, “x” marks are plots in the case where m = 4 in the evaluation function of (Equation 19), which is the minimum at the point Q3. At the point Q3, the value of α is −0.03. When plots of the evaluation functions are compared, if m becomes a large number, (Equation 19) gradually approaches (Equation 17). This is because the evaluation function given by (Equation 19) is a calculation formula obtained by extending (Equation 17). When the results calculated for point Q1 (α = −0.035), point Q2 (α = −0.009) and point Q3 (α = −0.03) in Table 3 are compared, output shortage s _k The result of the point Q3 is between the point Q1 and the point Q2. In other words, it is possible to determine whether to place importance on minimizing the output shortage for each individual coil or on minimizing the total energy shortage by appropriately determining the value of m.
As described above, according to the present embodiment, when output shortage occurs, the output shortage is biased to a specific coil by determining the common command value α using (Equation 17) or (Equation 19). Adverse system impacts can be suppressed.
[0176]
In the first to fourth embodiments, the motor element and the lens driving device are exemplified as the circuit elements driven by the circuit element driving device of the present invention. However, other various circuit elements are used as the circuit elements of the present invention. You may drive by an element drive device.
[0177]
For example, when driving an articulated robot having a plurality of motors, the circuit element driving device of the present invention can be suitably used. The multi-joint robot has a large number of built-in motors, but the number of wires connected to the motor increases because the motor is required to have more than the number of degrees of freedom of joints. On the other hand, since the motor of an articulated robot requires a lot of torque, the voltage applied to each motor cannot be lowered. In such a case, by using the circuit element driving device of the present invention, the number of wirings can be reduced without reducing the applied voltage. Further, the control method according to the present invention is not limited to the articulated robot, and can be applied to various other fields.
[0178]
【The invention's effect】
According to the circuit element driving device of the present invention, when driving a plurality of circuit elements having a common terminal to reduce the number of wires, the instantaneous maximum voltage that can be applied to one circuit element is not reduced, Circuit elements can be driven independently. It also has a function of redistributing power to circuit elements that lack output. In particular, when the output is generally insufficient, the power supply ratio to the circuit element can be changed so that the influence on the driving device is minimized. In particular, when it is desired to drive three coils independently by the lens driving device, the number of necessary terminals can be reduced to four. Therefore, no extra wiring is required, and the adverse effect on the conductive elastic body supporting the lens can be eliminated. Furthermore, the number of wiring steps can be reduced.
[0179]
Further, when the command value of the drive unit is created from the input command value, the norm of the command value of the drive unit can be set to the minimum, so that there is an advantage that output saturation hardly occurs. Further, since the command value can be calculated by a linear matrix calculation unit including only a multiplication unit and an addition unit, the command value can be calculated at high speed.
[0180]
Further, by incorporating a non-linear calculation process for determining the output shortage of the drive unit, output saturation of the drive unit can be effectively avoided. Further, the power redistribution can be set in detail by evaluating the output shortage using a weighted evaluation function intended by the designer. By appropriately selecting the evaluation function, it is possible to place importance on minimizing the output shortage amount of each circuit element, or on minimizing the overall energy shortage amount. The common command value α that minimizes the evaluation function can be obtained efficiently.
[0181]
The circuit element driving device of the present invention can also be used for driving a spindle motor. Compared with the case where the common terminal is fixed at a constant voltage, the driving can be performed with a current of about 16% higher wave height. In addition, when driving circuit elements using periodic signals, such as when driving a spindle motor, if common command values are stored in the memory, the number of arithmetic circuits can be reduced, time required for arithmetic processing, and power consumption can be reduced. There is an advantage that it can be reduced.
[0182]
Further, according to the present invention, (n + 1) drive circuits may be prepared to drive n circuit elements. For this reason, compared with the prior art which required 2n drive circuits, the circuit per circuit element can be comprised simply. Furthermore, when a switching command is issued through the DSP or microcomputer I / O port, the number of bits required to drive n coils is only (n + 1).
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of a circuit element driving apparatus according to the present invention.
FIG. 2 shows waveforms for explaining the operation of the circuit element driving apparatus shown in FIG.
FIG. 3 is a perspective view showing a lens driving device according to a second embodiment of the circuit element driving device of the present invention;
4 is a block diagram showing a circuit element driving circuit that drives the lens driving device shown in FIG. 3; FIG.
5 is a block diagram showing a configuration of a parameter determination unit that determines parameters used in a linear matrix calculation unit of the circuit element driving device shown in FIG. 5;
6A, 6B, and 6C show waveforms for explaining the operation of the circuit element driving device shown in FIG.
7 is a block diagram showing a modification of the linear matrix calculation unit of the circuit element driving apparatus shown in FIG.
FIG. 8 is a block diagram showing a third embodiment of a circuit element driving apparatus according to the present invention.
9 is a circuit diagram showing a specific configuration of a common command value calculation unit of the circuit element driving device shown in FIG. 8;
10 is a current command value u in FIG. 9; ₁ Is a graph showing the relationship with the intermediate calculation value β.
11 is a current command value u in FIG. 9; ₁ It is a graph which shows the relationship with output shortage amount s1.
12 is a current command value u in FIG. 9; ₁ Is a graph showing the relationship with the common command value α.
FIGS. 13A, 13B, and 13C show waveforms for explaining an operation for generating a voltage applied to the tracking coil 21. FIGS.
FIGS. 14A, 14B, and 14C show waveforms for explaining an operation for generating a voltage applied to the focus coil 22. FIGS.
15 is a block diagram showing a modification of the control unit of the circuit element driving device shown in FIG.
FIG. 16 is a circuit element drive device according to a fourth embodiment of the present invention (w _k ・ S _k ) And a common command value α.
FIG. 17 is a graph illustrating a relationship between a common command value α and an evaluation function in the fourth embodiment of the circuit element driving apparatus according to the present invention.
FIG. 18 is a circuit diagram illustrating a conventional method for driving a two-terminal circuit element.
FIG. 19 is a circuit diagram illustrating another conventional two-terminal circuit element driving method.
[Explanation of symbols]
1 Spindle motor
2, 3, 4 coils
5, 24 Common terminal
6 Drive unit
7, 36, 56 Control unit
8 Maximum value detector
9 Minimum value detector
10 Inversion average part
11, 12, 13, 29, 43, 44, 45 Adder
α Common command value
r ₁ , R ₂ , R _Three Correction command value
V _com Applied voltage to common terminal
V ₁ Applied voltage to individual terminal 2a
V ₂ Applied voltage to individual terminal 3a
V _Three Applied voltage to individual terminal 4a
20 Lens drive unit
21 Tracking coil
22 Focus coil
23 Tilt coil
25 Linear matrix calculation unit
26 Weight calculator
27 Generalized inverse matrix calculator
28 Multiplier
30 Switching drive unit
31, 32, 33, 34 Inversion element
35 Duty variable section
37 Reference signal generator
38, 39, 40, 41 Comparator
42, 52 Common command value calculator
46, 47, 48 operational amplifier
49 Inversion adder

Claims (16)

N first command values for generating a voltage to be applied to n (n is an integer of 2 or more) circuit elements having two terminals are received and based on the n first command values Control means for generating and outputting p second command values that are one greater than n;
Drive means for generating and outputting p drive voltages based on the p second command values;
The control means includes a linear matrix calculation means,
The linear matrix computing means multiplies the n first command values by a general inverse matrix of size p × n, and outputs the p second command values ,
At least one of the p drive voltages is a voltage that varies based on at least one of the first command values, and is commonly applied to one terminal of each of the two or more circuit elements. The circuit element driving device. The circuit element driving apparatus according to claim 1 , wherein the general inverse matrix is a general inverse matrix that minimizes a norm of the second command value. The circuit element driving apparatus according to claim 1 , wherein the general inverse matrix is a general inverse matrix that minimizes a norm with a weighting coefficient of the second command value. The circuit element driving apparatus according to claim 3 , wherein the control unit changes the weighting coefficient based on a history of the first command value. The circuit element driving apparatus according to claim 3 , wherein the weighting coefficient is determined using a norm related to a time of the first command value. N first command values for generating a voltage to be applied to n (n is an integer of 2 or more) circuit elements having two terminals are received and based on the n first command values Control means for generating and outputting p second command values that are one greater than n;
Drive means for generating and outputting p drive voltages based on the p second command values;
The driving means should apply to a common terminal connected to one end of each of the n circuit elements and n individual terminals provided with the other ends of the n circuit elements independently (n + 1). Drive voltage,
The control means receives the n first command values and outputs the (n + 1) second command values to the drive means to generate the (n + 1) drive voltages;
k is an integer from 1 to n representing the number of the circuit element,
Wherein said control means includes a maximum value detection means for detecting a maximum value u _max of the n first command value u _k, the minimum value u _min of the n first command value uk Minimum value detecting means for detecting, and using at least u _max and u _min to generate the second command value α for generating a drive voltage to be applied to the common terminal, the command value α to generate a second command value r _k of n give added to the individual terminals on each of said n first command value u _k,
At least one of the p drive voltages is a voltage that varies based on at least one of the first command values, and is commonly applied to one terminal of each of the two or more circuit elements. The circuit element driving device. The circuit element driving apparatus according to claim 6 , wherein the control unit generates the second command value α by inverting and outputting an average value of the maximum value u _max and the minimum value u _min . N first command values for generating a voltage to be applied to n (n is an integer of 2 or more) circuit elements having two terminals are received and based on the n first command values Control means for generating and outputting p second command values that are one greater than n;
Drive means for generating and outputting p drive voltages based on the p second command values;
The driving means should apply to a common terminal connected to one end of each of the n circuit elements and n individual terminals provided with the other ends of the n circuit elements independently (n + 1). Drive voltage,
The control means receives the n first command values and outputs the (n + 1) second command values to the drive means to generate the (n + 1) drive voltages ;
The drive means has a non-saturation range that generates the drive voltage proportional to the second command value, and a non-saturation function that generates a constant drive voltage regardless of the second command value. The control means calculates the (n + 1) second command values using a non-linear relationship from the n first command values,
k is an integer from 1 to n representing the number of the circuit element,
In the control means, when the (n + 1) second command values are larger than the maximum value of the non-saturation range or smaller than the minimum value, the n first commands for the non-saturation range. Output shortage calculating means for giving an excess of the value u _k as n output shortages s _k ;
The second command value α to be given to the common terminal is generated using at least one of the n output deficiencies s _k , and the second command value α is set to the n first command values α. is added to the command value u _k to generate the n second command value r _k given to the individual terminals,
At least one of the p drive voltages is a voltage that varies based on at least one of the first command values, and is commonly applied to one terminal of each of the two or more circuit elements. The circuit element driving device. 9. The circuit element according to claim 8 , wherein the control means determines a second command value α so as to minimize the evaluation function using an evaluation function having the n output deficiencies s _k as arguments. Drive device. The circuit element driving apparatus according to claim 9 , wherein the evaluation function is a function that outputs a maximum value of the output shortage amount s _k . The circuit element driving apparatus according to claim 9 , wherein the evaluation function is a function weighted by a weighting factor w _k . The second procedure for obtaining a command value α is, the first command value u _j of the first command value u _i and the command value u _i and different from the j-th circuit element of the sign of the i-th circuit element A plurality of second command value candidates α _ij are obtained using a predetermined calculation formula relating to the second command value, and the second command value that minimizes the evaluation function from the plurality of second command value candidates α _ij The circuit element driving device according to claim 10 or 11 , wherein α is selected. The circuit element driving device according to claim 9 , wherein a norm of an output shortage amount s _k is used for the evaluation function. The second procedure for obtaining a command value α is, the first command value u _j of the first command value u _i and the command value u _i and different from the j-th circuit element of the sign of the i-th circuit element A plurality of initial value candidates α _ij are obtained using a predetermined calculation formula relating to the above, and an initial value α ₀ that minimizes the evaluation function is selected from the initial value candidates α _ij in the first iteration procedure, and then the initial value 14. The circuit according to claim 13 , wherein the second command value α that minimizes the evaluation function is searched using a second iterative procedure with a value α ₀ as a starting point and α = 0 as an initial search direction. Element driving device. The control means includes
Maximum value detecting means for detecting a maximum value s _max of the n output deficiencies s _k ;
Minimum value detecting means for detecting a minimum value s _min of the n output deficiencies s _k ,
9. The circuit element driving device according to claim 8 , wherein the second command value α to be given to a common terminal is generated using at least the maximum value s _max and the minimum value s _min . The circuit element driving device according to claim 15 , wherein an addition inverted output of the maximum value s _max and the minimum value s _min is the second command value α.

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