JP3089709B2 - Access servo mechanism for magnetic disk drive - Google Patents
Access servo mechanism for magnetic disk driveInfo
- Publication number
- JP3089709B2 JP3089709B2 JP03144529A JP14452991A JP3089709B2 JP 3089709 B2 JP3089709 B2 JP 3089709B2 JP 03144529 A JP03144529 A JP 03144529A JP 14452991 A JP14452991 A JP 14452991A JP 3089709 B2 JP3089709 B2 JP 3089709B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- magnetic disk
- drive
- track
- driving means
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Moving Of Head For Track Selection And Changing (AREA)
- Moving Of The Head To Find And Align With The Track (AREA)
- Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は磁気ディスク装置のアク
セスサーボ機構に係り、特に、高応答小ストロークの駆
動手段と、低応答大ストロークの駆動手段とを協調させ
て高速高精度アクセス動作を実現するヘッド位置決めサ
ーボ機構の制御系の構成に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an access servo mechanism for a magnetic disk drive, and more particularly, to realize a high-speed and high-accuracy access operation by coordinating a high-response small-stroke driving means and a low-response large-stroke driving means. The present invention relates to a configuration of a control system of a head positioning servomechanism to perform.
【０００２】[0002]
【従来の技術】従来の磁気ディスク装置のヘッドの位置
決めを行うアクセスサーボ機構では、磁気円板上に同心
円状に配置される各トラックに対して情報の読み書きを
行うために、磁気円板のラジアル方向にヘッドを駆動す
る手段としてボイスコイルモータを用いている。すなわ
ち、直動形または回転形軸受によって支持されたキャリ
ッジと呼ばれる部材の一端にボイスコイルモータの可動
コイル部が固定されており、他端に支持機構を介して固
定されているヘッドを動かしている。しかし、このキャ
リッジ部の等価質量は強度剛性面の制約から軽量化には
限界があり、ボイスコイルモータの推力についても質量
寸法発熱等の面からの制約があるので、従来の構成のま
ま、アクセスサーボ機構の高応答化によるアクセス時間
の短縮、トラック追従精度の向上を進めても限界があ
る。2. Description of the Related Art In a conventional access servo mechanism for positioning a head of a magnetic disk drive, a radial disk of a magnetic disk is used to read and write information on each track concentrically arranged on the magnetic disk. A voice coil motor is used as a means for driving the head in the direction. That is, a movable coil portion of a voice coil motor is fixed to one end of a member called a carriage supported by a linear or rotary bearing, and a head fixed to the other end via a support mechanism is moved. . However, the equivalent mass of the carriage has a limit in weight reduction due to the limitation of strength and rigidity, and the thrust of the voice coil motor is also limited by the heat generation of the mass dimension. There is a limit even if the response time of the servo mechanism is improved to shorten the access time and improve the track following accuracy.
【０００３】そこで、ボイスコイルモータよりも高い応
答性を備えた駆動手段を用いてこの限界を打破すること
が考えられている。このための駆動手段は一般にストロ
ークが小さいので、ボイスコイルモータと併用し、二段
サーボ系を構成する方法がとられている。たとえば、特
開昭60−35383 号公報には、ヘッド支持機構の部分に高
応答の微動アクチュエータを組み込み、位置フィードバ
ック信号に応じてこの微動アクチュエータを制御し、微
動アクチュエータの変位量を検出器によって検出して、
粗動アクチュエータの動作を制御する方式が示されてい
る。光ディスクの分野でも、同様な二段サーボ系を構成
する方法がとられており、たとえば特開平1−109577 号
公報には、検出されたヘッドの位置をフィードバックし
て位相補償演算を行った信号を周波数帯域分割し、粗動
系と微動系に入力する方式が示されている。また、特開
昭61−280080号公報には、精アクチュエータの周波数特
性をシミュレートする回路または精アクチュエータの動
きを検出する検出器を設け、これらの出力を粗アクチュ
エータの偏差入力とする方式が示されている。Therefore, it has been considered to overcome this limitation by using a driving means having a higher response than a voice coil motor. Since the drive means for this purpose generally has a small stroke, a method of using a voice coil motor in combination to form a two-stage servo system has been adopted. For example, in Japanese Patent Application Laid-Open No. 60-35383, a high-response fine-movement actuator is incorporated in the head support mechanism, the fine-movement actuator is controlled according to a position feedback signal, and the displacement of the fine-movement actuator is detected by a detector. do it,
A method of controlling the operation of the coarse actuator is shown. In the field of optical discs, a similar two-stage servo system has been adopted. For example, Japanese Patent Application Laid-Open No. 1-109577 discloses a signal obtained by feeding back a detected head position and performing a phase compensation operation. A method is shown in which a frequency band is divided and input to a coarse movement system and a fine movement system. JP-A-61-280080 discloses a method of providing a circuit for simulating the frequency characteristics of a fine actuator or a detector for detecting the movement of a fine actuator, and using these outputs as deviation inputs of a coarse actuator. Have been.
【０００４】[0004]
【発明が解決しようとする課題】第一の従来技術では、
微動アクチュエータの変位量を検出するための検出器を
キャリッジ部に設ける必要があり、装置の複雑化やキャ
リッジの等価質量の増大等の問題を解決することが必要
となる。また、二つのアクチュエータの制御系は複雑に
干渉する特性をもち、制御系の設計が難しい。第二の従
来技術では、周波数帯域分割に使用するフィルタの持つ
位相遅れ特性によってサーボ系の位相余裕が減少するた
め、特に低周波側を分担する粗動アクチュエータの応答
の高速化と安定化の両立を図った設計が難しくなる。第
三の従来技術では、精アクチュエータの周波数特性をシ
ミュレートする回路を設ける方式では、この回路と実機
との誤差があると、粗アクチュエータに対する動作の制
御が正しく行われない場合が生じる。また、精アクチュ
エータの動きを検出する検出器を設ける方法では、第一
の従来技術と同様な問題があらわれる。In the first prior art,
It is necessary to provide a detector for detecting the amount of displacement of the fine movement actuator in the carriage section, and it is necessary to solve problems such as the complexity of the apparatus and the increase in the equivalent mass of the carriage. In addition, the control system of the two actuators has complicated interference characteristics, and it is difficult to design the control system. In the second conventional technique, the phase delay characteristic of the filter used for frequency band division reduces the phase margin of the servo system. It becomes difficult to design with the aim. In the third conventional technique, in a method in which a circuit for simulating the frequency characteristic of a fine actuator is provided, if there is an error between the circuit and an actual machine, the operation of the coarse actuator may not be controlled properly. Further, in the method of providing the detector for detecting the movement of the fine actuator, the same problem as in the first related art appears.
【０００５】本発明の目的は、高応答であるがストロー
クの小さな駆動手段と、ストロークは大きいが応答性は
第一の駆動手段よりも低い駆動手段とを協調させて、高
い応答性能を持つアクセスサーボ機構を得ることにあ
る。SUMMARY OF THE INVENTION It is an object of the present invention to provide an access device having a high response performance by coordinating a driving means having a high response but a small stroke and a driving means having a large stroke but a lower response than the first driving means. The object is to obtain a servo mechanism.
【０００６】[0006]
【課題を解決するための手段】本発明は、磁気円板上に
あらかじめ記録されているサーボ情報から目標トラック
の中心に対するヘッドの相対位置を検出し、目標位置で
あるトラックの中心位置と比較して、第一の駆動手段及
び前記第二の駆動手段の双方にフィードバックを施すと
ともに、第一の駆動手段の変位量を第二の駆動手段の制
御系の目標値に加算してやることで、ふたつの駆動手段
の効果的な協調動作を実現するとともに、このような二
段サーボ系の設計や調整を容易にしたものである。According to the present invention, a relative position of a head with respect to the center of a target track is detected from servo information prerecorded on a magnetic disk and compared with the center position of the target track. By applying feedback to both the first drive means and the second drive means and adding the displacement of the first drive means to the target value of the control system of the second drive means, An effective cooperative operation of the driving means is realized, and the design and adjustment of such a two-stage servo system are facilitated.
【０００７】[0007]
【作用】図１は、本発明に基づくサーボ系における信号
の伝達特性を示すブロック線図である。第一の駆動手段
及び動特性補償要素の伝達関数をＧ１(ｓ)とし、第二の
駆動手段及び動特性補償要素の伝達関数をＧ２(ｓ)とす
れば、このサーボ系の特性方程式は、FIG. 1 is a block diagram showing signal transmission characteristics in a servo system according to the present invention. If the transfer function of the first drive means and the dynamic characteristic compensation element is G1 (s), and the transfer function of the second drive means and the dynamic characteristic compensation element is G2 (s), the characteristic equation of this servo system is as follows.
【０００８】[0008]
【数１】 (Equation 1)
【０００９】となる。ここで、## EQU1 ## here,
【００１０】[0010]
【数２】 (Equation 2)
【００１１】は、第一の駆動手段及び動特性補償要素の
みでフィードバック制御系を構成したときの特性方程式
であり、Is a characteristic equation when a feedback control system is constituted by only the first driving means and the dynamic characteristic compensating element,
【００１２】[0012]
【数３】 (Equation 3)
【００１３】は、第二の駆動手段及び動特性補償要素の
みでフィードバック制御系を構成したときの特性方程式
であるから、各々単独のサーボ系が安定であれば二段サ
ーボ系を構成したときも必ず安定に動作し、単独のサー
ボ系の極を合わせたものが二段サーボ系の極になること
がわかる。これは、サーボ系の設計や調整を行う際に非
常に好都合な特性である。Is a characteristic equation when a feedback control system is constituted only by the second drive means and the dynamic characteristic compensating element. Therefore, if a single servo system is stable, a two-stage servo system can be constructed. It can be seen that it always operates stably, and the combination of the poles of a single servo system becomes the pole of a two-stage servo system. This is a very advantageous characteristic when designing and adjusting the servo system.
【００１４】これに対して、従来の構成の二段サーボ系
の一例における信号の伝達特性を示すブロック線図を図
２に示す。この系では、特性方程式は、On the other hand, FIG. 2 is a block diagram showing signal transmission characteristics in an example of a conventional two-stage servo system. In this system, the characteristic equation is
【００１５】[0015]
【数４】 (Equation 4)
【００１６】となる。また、従来の構成の二段サーボ系
の他の例における信号の伝達特性を示すブロック線図を
図３に示す。この系では、特性方程式は、## EQU1 ## FIG. 3 is a block diagram showing a signal transmission characteristic in another example of a conventional two-stage servo system. In this system, the characteristic equation is
【００１７】[0017]
【数５】 (Equation 5)
【００１８】となる。これらの構成では、本発明に基づ
くサーボ系のような各々単独のサーボ系と二段サーボ系
との間の好都合な関係は成立せず、二段サーボ系として
あらためて設計，調整を考える必要がある。## EQU1 ## In these configurations, an advantageous relationship between each single servo system such as the servo system according to the present invention and the two-stage servo system is not established, and it is necessary to reconsider the design and adjustment as a two-stage servo system. .
【００１９】また、本発明に基づく図１のサーボ系の閉
ループ伝達関数Ｇ(ｓ)は、Further, the closed loop transfer function G (s) of the servo system of FIG.
【００２０】[0020]
【数６】 (Equation 6)
【００２１】となる。各々単独のサーボ系がオフセット
なしに目標値に整定する場合には、この二段サーボ系も
オフセットなしに目標値に整定することはあきらかであ
る。ここでは、第一の駆動手段の応答が速く、第二の駆
動手段の応答が遅い場合を例にとってこのサーボ系の応
答を説明する。本発明に基づくサーボ系では、目標トラ
ックの中心に対して、現在のヘッド位置がずれた場合、
第一及び第二の駆動手段の制御系に制御偏差が生じる。
双方の制御系は各々の制御動作に従って操作量を算出し
て出力し、これらの信号は、各々対応する駆動手段に入
力される。これに応じて双方の駆動手段は位置ずれの訂
正動作を開始するが、第一の駆動手段は第二の駆動手段
にくらべて応答が速いため、ヘッドが目標トラックの中
心に整定して制御偏差が０になった時点では第一の駆動
手段の変位量は大きく、第二の駆動手段の変位量は小さ
い。このままの状態では、第一の駆動手段は中立点から
大きくずれた位置にあるが、第一の駆動手段の変位量は
第二の駆動手段の目標値に加算されているため、第二の
駆動手段は制御偏差が０になった状態でも引き続き第一
の駆動手段の変位量を減少させる方向に動作を行う。こ
れに伴って第一の駆動手段も動作するので、ヘッドを目
標トラック中心上に保ったまま、第一の駆動手段の変位
量が減少し、やがて変位量が０、すなわち、中立位置に
達するとサーボ系は全体が定常状態となる。## EQU1 ## If each individual servo system settles to the target value without offset, it is apparent that the two-stage servo system also settles to the target value without offset. Here, the response of this servo system will be described by taking as an example a case where the response of the first drive means is fast and the response of the second drive means is slow. In the servo system according to the present invention, when the current head position is shifted from the center of the target track,
A control deviation occurs in the control system of the first and second drive means.
Both control systems calculate and output an operation amount according to each control operation, and these signals are respectively input to corresponding driving means. In response to this, both the driving means start the operation of correcting the displacement, but since the first driving means responds faster than the second driving means, the head is settled at the center of the target track and the control deviation is corrected. Becomes zero, the displacement of the first driving means is large, and the displacement of the second driving means is small. In this state, the first driving means is at a position greatly deviated from the neutral point, but since the amount of displacement of the first driving means has been added to the target value of the second driving means, the second driving means The means continues to operate in the direction of decreasing the amount of displacement of the first driving means even when the control deviation becomes zero. Accordingly, the first driving means also operates, so that the displacement amount of the first driving means decreases while the head is kept at the center of the target track, and when the displacement amount reaches zero, that is, reaches the neutral position. The entire servo system is in a steady state.
【００２２】[0022]
【実施例】以下、本発明の実施例を図を用いて詳細に説
明する。図４は、本発明に基づく磁気ディスク装置のサ
ーボ系の構成を示すブロック図である。図４において、
スピンドルモータ１０１により一定速度で回転させられ
ている磁気円板の下面111はサーボ面となっており、あ
らかじめサーボ信号が記録されている。このサーボ信号
は、サーボ面に対向して設けられているサーボヘッド１
１２によって検出されて、増幅器１１３をへて位置検出
回路１２０に入力される。また、磁気円板の上面１１５
は、データを記憶するためのデータ面となっており、こ
の面に対向して設けられているデータヘッド１１６によ
りデータの読み書きが行われる。さて、位置検出回路１
２０は、サーボ信号を処理して位置決め制御系で使用さ
れる位置信号に変換する。本実施例の位置決めサーボ系
は、通常の磁気ディスク装置と同様に、目標トラックに
向けてトラック間の移動動作を行うシーク動作モード
と、目標トラックの中心にヘッドを追従させるフォロイ
ング動作モードの二つの動作モードを持っている。ま
ず、シーク動作モードでは、動作を開始する際には、入
力切り替えスイッチ１５０，入力切り替えスイッチ１５
１は、ともに上側に接続された状態となっている。位置
信号は、トラッククロッシング検出回路１３１で処理さ
れて、ヘッドがトラックの境界を通過することにパルス
を発生させる。このパルスは、残トラック数カウンタ１
３２に入力される。この残トラック数カウンタ１３２に
は、シーク動作開始時に目標トラック番号と現在のトラ
ック番号との差の値１３３が設定され、トラッククロッ
シングパルスを計数して値を更新していき、常に、現在
ヘッドがあるトラックの番号と目標トラックの番号との
差の値、すなわち、残トラック数を検出する。この残ト
ラック数の値は目標速度信号発生回路１４０に入力され
る。この目標速度信号発生回路１４０は、残トラック数
に応じて、目標速度テーブル及びこの目標速度に対応す
る加速度フィードフォワードテーブルを参照し、速度指
令値を出力する。この速度指令値は、減算回路１４１に
入力されて、後述する速度信号との差をとられ、速度偏
差が算出される。この速度偏差は、パワーアンプ１６１
で増幅されてボイスコイルモータ170を駆動する。ボイ
スコイルモータ１７０に流れる電流の値および位置信号
は、速度検出回路１８０に入力され、速度推定演算処理
が施されて速度信号が算出され、減算回路１４１に入力
される。一方、残トラック数カウンタ１３２の状態に応
じて圧電素子クランプ指令回路１９０が動作し、シーク
方向に向けて圧電素子をストロークエンドまで変位させ
る変位指令信号が出力される。この変位指令信号は入力
切り替えスイッチ１５１をへて、圧電素子駆動アンプ１
９１で増幅され、圧電素子１９２を駆動する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 4 is a block diagram showing the configuration of the servo system of the magnetic disk drive according to the present invention. In FIG.
The lower surface 111 of the magnetic disk rotated at a constant speed by the spindle motor 101 is a servo surface, and servo signals are recorded in advance. This servo signal is transmitted to the servo head 1 provided opposite the servo surface.
12 and is input to the position detection circuit 120 via the amplifier 113. Also, the upper surface 115 of the magnetic disk
Is a data surface for storing data, and data is read and written by a data head 116 provided opposite to this surface. Now, the position detection circuit 1
Numeral 20 processes the servo signal and converts it into a position signal used in a positioning control system. The positioning servo system according to the present embodiment has two modes, a seek operation mode for performing a movement operation between tracks toward a target track, and a following operation mode for causing a head to follow the center of the target track, similarly to a normal magnetic disk device. Has an operation mode. First, in the seek operation mode, when the operation is started, the input changeover switch 150 and the input changeover switch 15 are used.
1 are both connected to the upper side. The position signal is processed by a track crossing detection circuit 131 to generate a pulse when the head passes a track boundary. This pulse is output from the remaining track number counter 1
32. At the start of the seek operation, the value 133 of the difference between the target track number and the current track number is set in the remaining track number counter 132, the track crossing pulse is counted and the value is updated. A value of a difference between a certain track number and a target track number, that is, the number of remaining tracks is detected. The value of the number of remaining tracks is input to the target speed signal generation circuit 140. The target speed signal generating circuit 140 outputs a speed command value by referring to the target speed table and the acceleration feedforward table corresponding to the target speed according to the number of remaining tracks. This speed command value is input to the subtraction circuit 141, and the difference between the speed command value and a speed signal described later is calculated to calculate a speed deviation. This speed deviation is determined by the power amplifier 161
And drives the voice coil motor 170. The value of the current flowing through the voice coil motor 170 and the position signal are input to a speed detection circuit 180, which performs speed estimation calculation processing to calculate a speed signal, and inputs the speed signal to a subtraction circuit 141. On the other hand, the piezoelectric element clamp command circuit 190 operates according to the state of the remaining track number counter 132, and outputs a displacement command signal for displacing the piezoelectric element toward the seek direction to the stroke end. The displacement command signal is supplied to the input element switch 151 and the piezoelectric element drive amplifier 1
It is amplified at 91 and drives the piezoelectric element 192.
【００２３】シーク動作が進行し、目標トラックに接近
して、ヘッドが所定の位置に到達すると、入力切り替え
スイッチ１５１が下側に切り替えられ、変位指令信号は
フォロイング制御回路２００の出力になる。また、所定
の位置偏差量あるいは速度値に到達すると、入力切り替
えスイッチ１５０が下側に切り替えられる。フォロイン
グ制御回路２００の内容について次に説明する。When the seek operation progresses, approaches the target track, and the head reaches a predetermined position, the input changeover switch 151 is switched to the lower side, and the displacement command signal is output from the following control circuit 200. When a predetermined position deviation amount or speed value is reached, the input changeover switch 150 is switched to the lower side. The following describes the contents of the following control circuit 200.
【００２４】図５は、本発明に基づくフォロイング制御
回路２００の構成の一例を示すブロック図である。入力
部２０１には位置信号が入力される。この位置信号は第
一の位相補償回路２０２で処理されて、ノッチフィルタ
２０３及び加算回路２０４をへて第一の出力部２０６に
出力される。加算回路２０４では、圧電素子を中立点を
中心として伸縮させるために、オフセット電圧源２０５
から供給されるオフセット信号が加算される。また、位
置信号は加算回路２０７にも入力されている。この加算
回路の他の入力は第一の位相補償回路２０２の出力に接
続されており、加算結果は第二の位相補償回路２０８及
びノッチフィルタ２０９を経て第二の出力部２１０に出
力される。第一の出力部２０６は図４の入力切り替えス
イッチ１５１に接続され、第二の出力部２１０は図４の
入力切り替えスイッチ１５０に接続される。この実施例
では、第一の駆動手段が圧電素子であり、入力信号にほ
ぼ比例した変位を生じる。このような要素のフィードバ
ック制御系を構成するために、位相補償回路に積分特性
をもたせている。また、圧電素子の変位量信号を取り出
すため、検出器を設けるかわりに変位量にほぼ比例した
圧電素子の駆動信号を用いており、これをボイスコイル
モータの位相補償回路に入力している。FIG. 5 is a block diagram showing an example of the configuration of the following control circuit 200 according to the present invention. The input unit 201 receives a position signal. This position signal is processed by the first phase compensation circuit 202 and output to the first output unit 206 via the notch filter 203 and the addition circuit 204. The adder circuit 204 includes an offset voltage source 205 to expand and contract the piezoelectric element around a neutral point.
Are added. Further, the position signal is also input to the adding circuit 207. The other input of this adder circuit is connected to the output of the first phase compensation circuit 202, and the addition result is output to the second output section 210 via the second phase compensation circuit 208 and the notch filter 209. The first output unit 206 is connected to the input switch 151 of FIG. 4, and the second output unit 210 is connected to the input switch 150 of FIG. In this embodiment, the first driving means is a piezoelectric element, and generates a displacement substantially proportional to an input signal. In order to constitute a feedback control system of such an element, the phase compensation circuit has an integral characteristic. Further, in order to extract a displacement signal of the piezoelectric element, a drive signal of the piezoelectric element which is almost proportional to the displacement is used instead of providing a detector, and this is input to a phase compensation circuit of the voice coil motor.
【００２５】図６は、第一の位相補償回路２０２の構成
を示す回路図である。この回路は積分特性を持ってお
り、図５の入力部２０１の信号を積分した値をノッチフ
ィルタ２０３及び加算回路２０７に供給するが、積分値
を記憶するコンデンサ２３１の電圧は、二つのツェナー
ダイオード２３２，２３３によって限界値が設定されて
おり、限界値を越えた電圧が積分値としてあらわれるこ
とはない。この限界値は、圧電素子の限界電圧に対応し
て設定されており、圧電素子による駆動手段のストロー
クを決定している。FIG. 6 is a circuit diagram showing the configuration of the first phase compensation circuit 202. This circuit has an integration characteristic and supplies a value obtained by integrating the signal of the input unit 201 in FIG. 5 to the notch filter 203 and the addition circuit 207. The voltage of the capacitor 231 storing the integrated value is equal to two Zener diodes. A limit value is set by 232 and 233, and a voltage exceeding the limit value does not appear as an integral value. This limit value is set corresponding to the limit voltage of the piezoelectric element, and determines the stroke of the driving means by the piezoelectric element.
【００２６】図７は、第一の位相補償回路２０２の他の
構成を示す回路図である。この回路は一次遅れ特性を持
っており、図６の回路にくらべてフィードバック抵抗２
３４が付加されており、低周波側でのゲインが低く設定
される点が異なっており、その他は同一の特性を持つ。FIG. 7 is a circuit diagram showing another configuration of the first phase compensation circuit 202. This circuit has a first-order lag characteristic, and has a feedback resistor 2 compared to the circuit of FIG.
34 in that the gain on the low frequency side is set low, and the other characteristics are the same.
【００２７】[0027]
【発明の効果】本発明によれば、高応答であるがストロ
ークの小さな駆動手段と、ストロークは大きいが応答性
は前記駆動手段よりも低い駆動手段とを効果的に協調さ
せて、高い応答性能を持つアクセスサーボ機構が得られ
るとともに、このような二段サーボ系の設計や調整が容
易になる。According to the present invention, a high-response, small-stroke drive means and a large-stroke, but low-response drive means are effectively coordinated with each other to achieve high response performance. And the design and adjustment of such a two-stage servo system are facilitated.
【図１】本発明に基づくサーボ系における信号の伝達特
性を示すブロック線図。FIG. 1 is a block diagram showing signal transmission characteristics in a servo system according to the present invention.
【図２】従来の構成の二段サーボ系の一例における信号
の伝達特性を示すブロック線図。FIG. 2 is a block diagram showing signal transmission characteristics in an example of a conventional two-stage servo system.
【図３】従来の構成の二段サーボ系の他の例における信
号の伝達特性を示すブロック線図。FIG. 3 is a block diagram showing signal transmission characteristics in another example of a conventional two-stage servo system.
【図４】本発明に基づく磁気ディスク装置のサーボ系の
構成を示すブロック図。FIG. 4 is a block diagram showing a configuration of a servo system of the magnetic disk drive according to the present invention.
【図５】本発明に基づくフォロイング制御回路の構成の
一例を示すブロック図。FIG. 5 is a block diagram showing an example of a configuration of a following control circuit according to the present invention.
【図６】本発明に基づく第一の位相補償回路の構成を示
す回路図。FIG. 6 is a circuit diagram showing a configuration of a first phase compensation circuit according to the present invention.
【図７】本発明に基づく第一の位相補償回路の他の構成
を示す回路図。FIG. 7 is a circuit diagram showing another configuration of the first phase compensation circuit according to the present invention.
ｒ…位置目標値、ｙ…変位量、１１１…サーボ面、１１
２…サーボヘッド、１６１…パワーアンプ、１７０…ボ
イスコイルモータ、１９１…圧電素子駆動アンプ、１９
２…圧電素子、２００…フォロイング制御回路、２０２
…積分回路。r: target position value, y: displacement amount, 111: servo surface, 11
2: Servo head, 161: Power amplifier, 170: Voice coil motor, 191: Piezoelectric element drive amplifier, 19
2: Piezoelectric element, 200: Following control circuit, 202
... Integration circuit.
フロントページの続き (56)参考文献 特開 平２−267782（ＪＰ，Ａ) 特開 平１−143086（ＪＰ，Ａ) 特開 平４−45916（ＪＰ，Ａ) 特開 平３−49040（ＪＰ，Ａ) 特開 平１−300431（ＪＰ，Ａ) 特開 昭60−45949（ＪＰ，Ａ) 特開 昭51−39012（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G11B 21/10 G11B 21/08 G11B 7/08 - 7/095 Continuation of the front page (56) References JP-A-2-26782 (JP, A) JP-A-1-143086 (JP, A) JP-A-4-45916 (JP, A) JP-A-3-49040 (JP) JP-A-1-300431 (JP, A) JP-A-60-45949 (JP, A) JP-A-51-39012 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB G11B 21/10 G11B 21/08 G11B 7/08-7/095
Claims (4)
うために、磁気ヘッドを所定のトラック上に位置決めす
る際に、高応答であるがストロークの小さい第一の駆動
手段と、所要範囲全体にわたって動作可能なストローク
をもつが応答は遅い第二の駆動手段とを協調させて、ト
ラック間の移動動作と、トラックへの追従動作とを切り
替えてアクセス動作を行う磁気ディスク装置のアクセス
サーボ機構において、 前記磁気ヘッドの位置を検出して、この位置信号をフィ
ードバックして目標位置と比較して偏差を求め、前記偏
差信号によって前記第一の駆動手段を駆動するととも
に、前記偏差信号と前記第一の駆動手段の変位信号との
和を求める加算手段を設け、前記加算手段の信号によっ
て前記第二の駆動手段を駆動することでトラック追従動
作を行うことを特徴とする磁気ディスク装置のアクセス
サーボ機構。A first drive means which has a high response but a small stroke when positioning a magnetic head on a predetermined track in order to write and read information on and from a magnetic disk; An access servo mechanism of a magnetic disk drive that performs an access operation by switching between a movement operation between tracks and an operation following a track by cooperating with a second drive unit having a stroke operable over a long time but a slow response. Detecting the position of the magnetic head, feeding back the position signal and comparing the position signal with a target position to determine a deviation, driving the first driving means with the deviation signal, and comparing the deviation signal with the first signal; An adding means for obtaining the sum of the displacement signal of the driving means and the second driving means driven by the signal of the adding means to follow the track. An access servo mechanism for a magnetic disk drive that performs an operation.
うために、磁気ヘッドを所定のトラック上に位置決めす
る際に、高応答であるがストロークの小さい第一の駆動
手段と、所要範囲全体にわたって動作可能なストローク
をもつが応答は遅い第二の駆動手段とを協調させて、ト
ラック間の移動動作と、トラックへの追従動作とを切り
替えてアクセス動作を行う磁気ディスク装置のアクセス
サーボ機構において、 前記磁気ヘッドの位置を検出して、この位置信号を前記
第一の駆動手段、及び第二の駆動手段の双方のサーボ系
にフィードバックしてそれぞれの目標位置との偏差値を
求め、前記第一の駆動手段は前記偏差値に基づいて駆動
すると共に、前記第一の駆動手段の推定変位量を求め、
前記第二の駆動手段の偏差値と前記第一の駆動手段の推
定変位量を加算する加算手段を設け、前記第二の駆動手
段を前記加算手段の出力を用いてトラック追従動作を行
うことを特徴とする磁気ディスク装置のアクセスサーボ
機構。A first drive unit which has a high response but a small stroke when positioning a magnetic head on a predetermined track in order to write and read information on and from a magnetic disk; An access servo mechanism of a magnetic disk drive that performs an access operation by switching between a movement operation between tracks and an operation following a track by cooperating with a second drive unit having a stroke operable over a long time but a slow response. Detecting the position of the magnetic head, and feeding back the position signal to the servo systems of both the first driving means and the second driving means to obtain a deviation value from each target position, One drive unit is driven based on the deviation value, and obtains an estimated displacement amount of the first drive unit,
An adder for adding the deviation value of the second drive unit and the estimated displacement amount of the first drive unit is provided, and the second drive unit performs a track following operation using an output of the adder unit. Characteristic access servo mechanism of magnetic disk drive.
うために、磁気ヘッドを所定のトラック上に位置決めす
る際に、高応答であるがストロークの小さい第一の駆動
手段と、所要範囲全体にわたって動作可能なストローク
をもつが応答は遅い第二の駆動手段とを協調させて、ト
ラック間の移動動作と、トラックへの追従動作を切り替
えてアクセス動作を行う磁気ディスク装置のアクセスサ
ーボ機構において、前記 第一の駆動手段は入力信号に略比例した変位を行
い、前記第一の駆動手段の位置決めを行う制御系は、目
標位置と現在位置との偏差を積分した値を操作量として
出力し、これを前記第一の駆動手段に入力する積分手段
を備え、前記積分手段は、前記第一の駆動手段のストロ
ークに対応する範囲内に操作量信号が保たれるように、
積分値を制限する飽和手段を備えたことを特徴とする磁
気ディスク装置のアクセスサーボ機構。To 3. To perform the Shi read out writing and information to the magnetic disk, in positioning a magnetic head on a predetermined track, a first drive means small stroke is a high response, the required Switch between track-to-track movement and track-following movement in coordination with the second drive means, which has a stroke that can operate over the entire range but has a slow response.
Ete the access servo mechanism of a magnetic disk apparatus for performing an access operation, the first driving means performs a displacement substantially proportional to the input signal, a control system for positioning of said first drive means, the target position and the current position And outputting the integrated value of the deviation as a manipulated variable and inputting the manipulated variable to the first driving means. The integrating means operates within a range corresponding to the stroke of the first driving means. So that the quantity signal is maintained
An access servo mechanism for a magnetic disk drive, comprising a saturation means for limiting an integral value.
うために、磁気ヘッドを所定のトラック上に位置決めす
る際に、高応答であるがストロークの小さい第一の駆動
手段と、所要範囲全体にわたって動作可能なストローク
をもつが応答は遅い第二の駆動手段とを協調させて、ト
ラック間の移動動作と、トラックへの追従動作とを切り
替えてアクセス動作を行う磁気ディスク装置のアクセス
サーボ機構において、前記 第一の駆動手段は入力信号に略比例した変位を行
い、前記第一の駆動手段の位置決めを行う制御系は、目
標位置と現在位置との偏差を積分した値を操作量として
出力し、これを前記第一の駆動手段に入力する積分手段
を備え、前記積分手段は、前記第一の駆動手段のストロ
ークに対応する範囲内に操作量信号が保たれるように、
積分値を制限する飽和手段を備え、前記第一の駆動手段
の入力信号に比例した信号を第二の駆動手段の目標値信
号に加算する手段を設けたことを特徴とする磁気ディス
ク装置のアクセスサーボ機構。4. A for performing Shi read out writing and information to the magnetic disk, in positioning a magnetic head on a predetermined track, a first drive means small stroke is a high response, the required Although having an operable stroke over a range and is by coordinating a slow second driving means responsive, cut and movement between tracks, and a tracking operation to the track
In the access servomechanism of the magnetic disk apparatus for performing an access operation in place, the first driving means performs a displacement substantially proportional to the input signal, a control system for positioning of said first drive means, the target position and the current An integration means for outputting a value obtained by integrating the deviation from the position as an operation amount and inputting the same to the first drive means, wherein the integration means is provided within a range corresponding to a stroke of the first drive means. So that the manipulated variable signal is maintained
An access unit for a magnetic disk drive, comprising: a saturation unit for limiting an integral value; and a unit for adding a signal proportional to an input signal of the first drive unit to a target value signal of the second drive unit. Servo mechanism.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03144529A JP3089709B2 (en) | 1991-06-17 | 1991-06-17 | Access servo mechanism for magnetic disk drive |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03144529A JP3089709B2 (en) | 1991-06-17 | 1991-06-17 | Access servo mechanism for magnetic disk drive |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04368676A JPH04368676A (en) | 1992-12-21 |
| JP3089709B2 true JP3089709B2 (en) | 2000-09-18 |
Family
ID=15364445
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03144529A Expired - Lifetime JP3089709B2 (en) | 1991-06-17 | 1991-06-17 | Access servo mechanism for magnetic disk drive |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3089709B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7019938B2 (en) | 2002-10-28 | 2006-03-28 | Matsushita Electric Industrial Co., Ltd. | Head positioning method, and disk apparatus using the same |
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| US8169736B2 (en) | 2009-07-17 | 2012-05-01 | International Business Machines Corporation | Method and apparatus to position a head module comprising servo elements and a plurality of data elements |
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1991
- 1991-06-17 JP JP03144529A patent/JP3089709B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7019938B2 (en) | 2002-10-28 | 2006-03-28 | Matsushita Electric Industrial Co., Ltd. | Head positioning method, and disk apparatus using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04368676A (en) | 1992-12-21 |
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