Multi-Stage Actuator Writer Position Determination
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Solution Overview
Problem
Dual-stage actuators in data storage devices face uncertainty in writer position estimation due to microactuator displacement, leading to potential overwriting of existing data during write operations, as the existing position error signal (PES) primarily estimates reader position, introducing writer position uncertainty.
Innovation Solution
A modified PES is generated to account for microactuator displacement, using a closed-loop microactuator position observer and a formulation module to estimate writer position, with a write fault interrupt triggered if the position exceeds a predetermined threshold, ensuring accurate writer positioning and preventing data overwrite.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the existing position error signal (PES) is used to estimate reader position in dual-stage actuators, then reader position estimation is achieved, but writer position estimation becomes uncertain leading to potential data overwrite
Solution Approach 1:
The patent introduces an intermediary calculation process that uses the known geometric relationship between the reader and writer elements combined with the microactuator displacement amount to derive writer position from reader position measurements. This intermediary approach allows the system to maintain accurate reader position estimation while simultaneously achieving reliable writer position estimation without requiring separate sensing mechanisms.
Solution Approach 2:
The patent replaces the need for separate mechanical position sensing mechanisms for the writer element by using computational methods. Instead of adding physical sensors to directly measure writer position, the system substitutes mechanical measurement with a calculation-based approach that uses existing reader position data and microactuator displacement information to determine writer position mathematically.
2Adaptability or versatility
If microactuator displacement is increased to improve positioning flexibility, then actuation capability is enhanced, but writer position uncertainty increases leading to data overwrite risk
Solution Approach 1:
The patent implements a feedback mechanism where the microactuator displacement amount is continuously measured and fed back to the controller. This feedback information is then used in real-time calculations to determine the actual writer position, allowing the system to maintain data integrity even when the microactuator is displaced from its neutral position. The feedback loop enables dynamic adjustment and monitoring of writer position throughout the actuation process.
3Manufacturing precision
If dual-stage actuation is used to enhance positioning precision, then actuation performance is improved, but writer position determination becomes complex and uncertain
Solution Approach 1:
The patent segments the position determination problem into distinct components: reader position measurement, microactuator displacement measurement, and geometric relationship parameters. By breaking down the complex writer position determination into these separable elements, the system can process each component independently and combine them through calculation to achieve accurate writer position determination without requiring a fundamentally more complex system architecture.
Data Source
AI summary
Apparatus and method for determining a position of a writer supported by a multi-stage actuator. In some embodiments, the apparatus includes a multi-stage actuator which supports a transducer adjacent a data recording surface. The multi-stage actuator has a coarse actuator and a microactuator. The transducer includes a write element and a read element. A controller is adapted to determine a position of a write element of the transducer with respect to the data recording surface responsive to a position of a read element of the transducer and a displacement distance of the microactuator away from a neutral position.