Multiple head control using common and differential position error signals
AssigneeSeagate Technology LLC
InventorsEvgeny Kharisov, Kenneth Haapala
Life of this patent
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Abstract
First and second position error signals (PES) are measured from respective first and second read heads that are simultaneously reading two different surfaces of a recording medium. A common repeatable runout (RRO) compensation signal and a differential RRO signal are determined based on the first and second PES. A voice coil motor that drives the first and second read heads is adjusted using the common RRO compensation signal, and first and second microactuators that respectively position the first and second read heads are adjusted based on the differential RRO signal.
Claims20
A method comprising:
- measuring first and second position error signals (PES) from respective first and second read heads that are simultaneously reading two different surfaces of a recording medium;
- determining a common repeatable runout (RRO) compensation signal and a differential RRO signal based on the first and second PES;
- adjusting a voice coil motor that drives the first and second read heads using the common RRO compensation signal;
- and
- adjusting first and second microactuators that respectively position the first and second read heads based on the differential RRO signal.
An apparatus comprising:
- a read channel configured to measure first and second position error signals (PES) from respective first and second read heads that are configured to simultaneously read two different surfaces of a recording medium;
- and
- a servo controller coupled to the read channel and configured to:
- determine a common repeatable runout (RRO) compensation signal and a differential RRO signal based on the first and second PES;
- adjust a voice coil motor that drives the first and second read heads using the common RRO compensation signal;
- and
- adjust first and second microactuators that respectively position the first and second read heads based on the differential RRO signal.
A method comprising:
- measuring first and second position error signals (PES) from respective first and second read heads that are simultaneously reading two different surfaces of a recording medium;
- adjusting a voice coil motor that drives the both first and second read heads using a first feedforward signal that comprises a sum of the first and second PES signals;
- and
- adjusting first and second microactuators that respectively position the first and second read heads based on second and third feedforward signals that comprise a difference between the first and second PES signals, the second and third feedforward signals having opposite signs.
Dependencies are inferred from the claim text.