Disk Actuator Driver Circuit Mode Switching
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Solution Overview
Problem
In disk apparatuses, the dual stage actuator technique faces challenges in accurately positioning heads due to limitations in control band improvement, particularly with the excitation of torsional and bending modes, which affect the precision and efficiency of data access processing.
Innovation Solution
The implementation of a driver circuit that switches the drive mode of fine movement actuators between InPhase and Scissors modes, depending on the magnetic head in use, to optimize control band improvement by canceling out reaction forces and suppressing unnecessary vibration, thereby enhancing the accuracy of head positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dual stage actuator technique is used to drive head by coarse and fine movement actuators, then head positioning capability is improved, but control band is limited due to excitation of torsional and bending modes
Solution Approach 1:
The system dynamically switches between InPhase and Scissors drive modes based on the operational requirements. The drive mode is changed according to the position of the magnetic head (inner or outer radius), allowing the system to adapt its control characteristics to different operating conditions and suppress unwanted vibrations effectively
Solution Approach 2:
The invention changes the drive mode parameter (InPhase or Scissors) depending on the magnetic head position. By switching between these two drive modes, the system optimizes the control band for different operational regions, suppressing torsional and bending modes that would otherwise limit positioning accuracy
2Measurement precision
If fine movement actuators are driven in InPhase mode, then head positioning is achieved, but torsional mode vibration is excited
Solution Approach 1:
The system dynamically selects between InPhase and Scissors modes based on magnetic head position. When the head is at the inner radius, InPhase mode is used; when at the outer radius, Scissors mode is used. This dynamic adaptation allows the system to achieve positioning while minimizing harmful vibrations for each specific operating condition
3Measurement precision
If fine movement actuators are driven in Scissors mode, then head positioning is achieved, but bending mode vibration is excited
Solution Approach 1:
The drive mode is dynamically changed according to magnetic head position. Scissors mode is employed when the head is at the outer radius where it provides effective positioning, while InPhase mode is used at the inner radius. This dynamic switching ensures that positioning accuracy is maintained while minimizing the excitation of bending modes in the relevant operational region
Data Source
AI summary
According to one embodiment, there is provided a disk apparatus including a first disk, a second disk, a main actuator, a first actuator, a second actuator, a third actuator, and a driver circuit. The driver circuit is configured to be able to switch between a first mode and a second mode. The first mode is a mode where a first actuator, a second actuator, and a third actuator are driven in a same direction. The second mode is a mode where the first actuator and the second actuator are driven in opposite directions and where the third actuator and the second actuator are driven in opposite directions.