| 摘要 |
The invention provides a positioning servo mechanism suitable for use in positioning the magnetic heads in a magnetic disk memory, and in which an actuator is driven in response to algebraically summed signals representing commanded position, actual position, and velocity.
<??>In a disk memory the head position may be determined by counting track crossings, giving a signal which has a fluctuating component and cannot be differentiated to give a usable velocity signal.
<??>In the present invention a coarse velocity signal is generated by integrating and amplifying a signal representing actuator current. The coarse velocity signal is integrated between successive track crossings to give a coarse distance signal. This is compared with a signal representing the actual distance between tracks, and the difference is used to adjust the gain of the amplifier, so correcting the coarse velocity signal at each track crossing. A further correction my be obtained by adding to the input of the first integrator an accumulative error correction signal representing the change in amplifier gain.
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