MA Amplifier Switching Control for HDD Positioning Accuracy
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Solution Overview
Problem
Conventional magnetic disk devices face challenges in maintaining positioning accuracy and random access performance due to vibration issues caused by the on/off switching of micro actuator amplifiers (MA amplifiers), which affects the efficiency of self servo write (SSW) processes.
Innovation Solution
The magnetic disk device incorporates a controller that manages the switching of MA amplifiers by starting up the destination MA amplifier while keeping the source MA amplifier on, and then switching after a predetermined time, thereby minimizing vibration and improving positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the MA amplifier is turned off to reduce standby power, then power consumption is reduced, but positioning accuracy deteriorates due to vibration during switching
Solution Approach 1:
The controller starts up the destination MA amplifier in advance before the source MA amplifier is turned off. This preliminary action ensures that the destination amplifier is ready and stable before switching occurs, minimizing vibration and positioning accuracy deterioration during the transition.
2Speed
If the MA amplifier switching is performed quickly, then random access performance is improved, but vibration increases causing positioning accuracy to deteriorate
Solution Approach 1:
The destination MA amplifier is activated and allowed to stabilize before the source amplifier is deactivated. This preliminary preparation reduces the impact of switching vibrations while maintaining fast overall switching performance.
3Productivity
If multiple MA amplifiers are provided to enable simultaneous driving, then productivity is improved, but device complexity increases
Solution Approach 1:
Each MA amplifier is designed to be capable of driving any micro actuator, not just a dedicated one. This multi-functionality allows the system to achieve simultaneous driving capability while managing the number of amplifiers efficiently, as they can be shared across different actuators.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the influence of micro actuator switching on the magnetic head's positioning accuracy and enhances the random access performance of the HDD by minimizing vibration and optimizing the switching process.
Implementation Method 1
a technology of providing an inclination to the voltage of the MA amplifier in a piezo drive circuit has been proposed
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a first MA amplifier that drives a first micro actuator that positions a corresponding magnetic head, a second micro actuator that positions a corresponding magnetic head, a second MA amplifier that drives the second micro actuator, and a controller that, when performing switching from an MA amplifier of a switching source in an on state to an MA amplifier of a switching destination in an off state, starts up the MA amplifier of the switching destination while maintaining the MA amplifier of the switching source in the on state, and performs the switching from the MA amplifier of the switching source to the MA amplifier of the switching destination after a predetermined time elapses.