Energy-Based Head Contact Detection in Hard Disk Drives
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Solution Overview
Problem
Existing hard disk storage devices face challenges in accurately determining contact between the read/write head and the storage medium, which can lead to component damage due to thermal element-induced contact, requiring advanced systems and methods for reliable touch down detection.
Innovation Solution
The implementation of an energy-based touch down detection system using a sensor to provide a sensor output indicating contact, with a touch down detection circuit comparing the energy value to a threshold value, calculated based on the mean and variance of the sensor output, to yield a contact output, thereby determining contact between the read/write head assembly and the storage medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a thermal element is used to control fly height, then the distance between read/write head and storage medium can be decreased, but contact between the head and storage medium may occur causing component damage
Solution Approach 1:
The patent applies preliminary action by detecting head contact conditions before actual contact damage can occur. The sensor monitors parameters (such as voltage, current, or impedance) that change when the head approaches the storage medium, and the controller takes preventive action by adjusting the thermal element or actuator to maintain safe fly height, preventing component damage before it happens.
Solution Approach 2:
The patent implements feedback by continuously monitoring sensor output signals that indicate head-to-medium proximity or contact conditions. The controller receives this feedback and automatically adjusts the thermal element heating or actuator position to maintain proper fly height, creating a closed-loop control system that prevents contact while enabling precise fly height control.
2Reliability
If contact detection systems are implemented, then component damage can be prevented, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a sensor and controller that serve multiple functions: they detect head contact conditions, monitor fly height, and control the thermal element or actuator. This multi-functional approach prevents contact damage without requiring entirely separate dedicated contact detection and control systems, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent implements self-service by enabling the existing sensor and controller infrastructure to perform contact detection and prevention functions. Rather than adding completely new dedicated contact detection hardware, the system uses its existing components (sensors for read/write operations, controllers for thermal/electrical control) to also monitor and prevent contact, reducing the need for additional complexity.
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 provides a reliable and accurate method for detecting contact, reducing the risk of component damage by using an energy-based binary output system that effectively characterizes contact through a calculated threshold value, enhancing the performance and reliability of hard disk drives.
Implementation Method 1
Heating the thermal element causes a distance between the read/write head and a storage medium to decrease
Data Source
AI summary
The present inventions are related to systems and methods for determining contact between two elements, and more particularly to systems and methods for determining contact between a head assembly and a storage medium.