Dynamic Fly-Height Control for Disk Drive Reliability
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Solution Overview
Problem
Current dynamic fly-height control technologies in disk drives are inadequate for individual hard drives operating under extreme environmental conditions, as they rely on population average values that can lead to over- or under-control, resulting in reliability issues and potential head crashes.
Innovation Solution
A method and system for dynamic fly-height control that measures current environmental parameters, determines an operation heater power based on these parameters, and adjusts the fly-height of a head using a touch down power module, environment module, and heater module, allowing for individualized touch down heater power calculations and interpolation to optimize fly-height adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If population average fly-height control values are used, then the control method is simple and easy to implement, but individual hard drives operating under extreme environmental conditions experience over- or under-control leading to reliability issues
Solution Approach 1:
The patent changes the control parameter from fixed population average values to dynamic environment-specific values. The system measures environmental parameters (temperature, pressure, humidity) and selects or calculates appropriate heater power values from pre-determined tables corresponding to different environmental conditions, allowing the fly-height control to adapt to varying operating conditions while maintaining reliability
Solution Approach 2:
The patent introduces dynamic adaptation by making the heater power values time-varying based on environmental conditions. Instead of using static population averages, the system continuously monitors environmental parameters and adjusts the control values in real-time, enabling the hard drive to maintain optimal fly-height control across different operating scenarios
2Device complexity
If population average fly-height control values are used, then the control system is less complex, but individual hard drives exhibit large deviations from average behavior causing control failures
Solution Approach 1:
The patent performs preliminary action by pre-determining heater power values for multiple environmental conditions during the manufacturing process. Tables of environment-specific heater power values are created and stored in the hard drive, so that when the drive operates under different environmental conditions, the appropriate control values are already available and can be applied immediately without complex real-time calculations
Solution Approach 2:
The patent uses copying by creating multiple copies of control parameters corresponding to different environmental conditions. Instead of using a single population average value, the system maintains multiple replicated control tables (e.g., TABLE 1 for first environment, TABLE 2 for second environment), allowing the hard drive to select the appropriate copy based on current environmental measurements
3Ease of manufacture
If simple fly-height control implementation is used, then manufacturing and deployment are easier, but head crashes occur due to inadequate control under extreme conditions
Solution Approach 1:
The patent applies beforehand cushioning by pre-calculating and storing heater power values for various environmental conditions during manufacturing. This preparatory action creates a buffer against environmental variations, ensuring that appropriate control values are already in place before the hard drive encounters extreme conditions, thereby preventing head crashes without requiring complex real-time adaptive control
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 effectively accounts for individual hard drive behaviors under extreme conditions, enhancing reliability and preventing head crashes by providing tailored heater power adjustments for precise fly-height control, thereby improving data storage performance and reducing wear.
Implementation Method 1
applying the operation heater power to adjust the fly-height of a head
Implementation Method 2
the transducer rides on a cushion of air generated by the motion of the disk
Data Source
AI summary
A method of dynamic fly-height control in a disk drive, comprising measuring current environmental parameters, determining an operation heater power based on the current environmental parameters, and applying the operation heater power to adjust the fly-height of a head. Using the current environmental parameters to interpolate an estimated current touch down heater power from the predetermined set of environmental parameters and plurality of corresponding touch down heater powers. A system of dynamic fly-height control includes a touch down power module to generate a plurality of environmental parameters and corresponding touch down heater powers, an environment module to receive the plurality of environmental parameters and corresponding touch down heater powers and generate an estimated touch down heater power based on measured current environmental parameters, and a heater module to receive the estimated touch down heater power and generate an operation heater power to control a fly-height of a head.