| 摘要 |
PURPOSE: To shorten the time needed for a positioning servo mechanism to position a head. CONSTITUTION: An eigenvector corresponding to the eigenvalue of the fastest negative real root is calculated within a range that does not exceed the follow-up characteristic of a VCM actuator 107 from the eigenvalues of an entire closed loop system of an n-th order control system which includes a head position signal 112 and a head speed signal 114 as the parts x1 and x2 of an internal state. Then the eigenvector is standardized so that the coefficient corresponding to the signal 112 is equal to 1 and stored as (n) pieces of coefficients [1, c1 , c2 , c3 ...cn ] in the same order as (n) pieces of internal states. An initial value setting means 123 fetches first both signals 112 and 114 during a head positioning operation and calculates the value of||x2 -c2 .x1||. When this value is reduced less than an integerεthat is satisfactorily small and can be allowed as an arithmetic error, the remaining (n-2) pieces of internal states of the n-th order control system are initialized only once so that they are equal to the ratio of the eigenvectors.
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