Parallel Head Actuation in Disk Drives
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Solution Overview
Problem
Current hard disk drive (HDD) technologies are limited by the ability to actuate only a single head, which restricts data access rate and servo performance, making it difficult to compete with solid state drives (SSDs) in terms of speed and efficiency.
Innovation Solution
A control architecture and design methodology for parallel actuation of multiple heads in HDD systems, utilizing a robust controller that simultaneously positions multiple read/write heads through micro actuators and coarse actuators, enabling parallel data streaming and enhanced performance comparable to single head actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If single head actuation is used, then device complexity is reduced, but data access rate and servo performance are limited
Solution Approach 1:
The actuation system is segmented into multiple independent micro actuators, each responsible for positioning a specific read/write head. This segmentation allows parallel operation of multiple heads while maintaining independent control over each head's positioning, thereby increasing data access rate without proportionally increasing overall system complexity
Solution Approach 2:
The patent transitions from single-head sequential operation to multi-head parallel operation by adding a dimensional aspect of simultaneous control. The controller manages multiple micro actuators in parallel, effectively adding a time-parallel dimension to the actuation process, which increases productivity without linearly increasing complexity
2Productivity
If multiple heads are actuated simultaneously, then data access rate is improved, but control precision and stability become more difficult to maintain
Solution Approach 1:
Each read/write head is paired with its own dedicated micro actuator, creating independent control channels. This segmentation allows the controller to manage positioning precision for each head individually using separate feedback loops, maintaining measurement precision even when multiple heads operate simultaneously
Solution Approach 2:
The patent implements feedback control for each micro actuator-head combination, where position error signals are generated and processed to adjust actuator output. This feedback mechanism ensures that positioning precision is maintained for each head independently, preventing degradation in measurement precision when multiple heads are actuated in parallel
3Reliability
If parallel head actuation is implemented, then servo performance is enhanced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The actuation system is divided into modular micro actuator units, each designed and manufactured using standardized processes. This segmentation enables independent manufacturing and assembly of identical modules, simplifying production while achieving parallel head actuation for enhanced servo performance
Solution Approach 2:
The micro actuators are designed as universal components that can be used across multiple head assemblies. This multi-functionality allows the same actuator design to serve multiple purposes in the system, reducing manufacturing complexity through component standardization while enabling enhanced servo performance through parallel operation
Data Source
AI summary
An apparatus includes a first read/write head coupled to a first micro actuator, a second read/write head coupled to a second micro actuator, an actuator and a controller. The actuator is coupled to both the first and second micro actuators. The controller is configured to position the first read/write head in response to a first micro actuator control signal and an actuator control signal. Further, the controller is configured to position the second read/write head in response to a second micro actuator control signal and the actuator control signal. The positioning of the first and second read/write heads by the controller is performed substantially simultaneously.