Read/Write Head Damping via Induced Coil Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing disk drives lack a method to control the position of a read/write head during periods when it is not reading or writing to an optical recording medium, leading to unmanaged vibration and movement.
Innovation Solution
A method that utilizes the same coil used for actuation during operation to sense and counteract the movement of the read/write head when it is inoperative, by inducing a counteracting current or voltage to exert a damping electromagnetic force, thereby reducing vibration and movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no actuation or control is applied to the read/write head during inoperative periods, then the device complexity is reduced and energy consumption is minimized, but vibration and movement of the head remain unmanaged
Solution Approach 1:
The existing coil, originally designed solely for actuating the read/write head during operative periods, is made to perform dual functions: it continues to actuate the head during operation and simultaneously serves as a sensor to detect head movement during inoperative periods through induced voltage measurement. This eliminates the need for separate sensing components while providing vibration damping capability.
Solution Approach 2:
The system continuously monitors the voltage induced in the coil during inoperative periods, which reflects head movement. Based on this feedback signal, a counteracting current is applied to the coil to generate an electromagnetic force that opposes the detected movement, creating a closed-loop control system that actively dampens vibrations without requiring additional sensors.
2Stability of the object's composition
If a separate sensing system is added to detect head movement during inoperative periods, then head position stability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The coil is designed to serve dual purposes: actuation during operative periods and sensing during inoperative periods. By measuring the voltage induced in the same coil when the head moves during idle periods, the system achieves sensing functionality without adding separate sensors, thereby reducing device complexity while maintaining head position stability.
Solution Approach 2:
The coil serves itself by utilizing its own electromagnetic properties for both actuation and sensing functions. The movement of the head induces voltage in the coil, and this same coil generates the counteracting electromagnetic force, creating a self-contained system that reduces overall device complexity.
3Device complexity
If the same coil is used for both sensing and actuation, then device complexity is reduced and manufacturing cost is lowered, but the coil must perform multiple functions that may interfere with each other
Solution Approach 1:
The system dynamically switches between different operational modes: during operative periods, the coil receives controlled current for actuation; during inoperative periods, the coil operates in sensing mode where head movement induces voltage. The controller adapts the coil's function based on the operational state, allowing the same component to perform multiple functions without interference by managing them in distinct temporal phases.
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 minimizes vibration of the read/write head during non-operational periods, allowing the same coil to both sense and actuate the head, and can dampen oscillatory shocks before they reach peak levels, significantly reducing movement and improving stability.
Implementation Method 1
the movement of the magnet may create a magnetic field by which the movement of the head may be sensed. Particularly, the movement of the magnet may create a magnetic field that induces current through, and/or voltage across, the coil
Implementation Method 2
current induced through, and/or voltage induced across, the coil by the magnet in the moving head is sensed and is used in creating a counteracting current through, and/or voltage across, the coil. The counteracting current and/or voltage results in a counteracting electromagnetic force being exerted on the head
Data Source
AI summary
A method of controlling a head for a recording medium includes determining that the head is in an inoperative state, and activating a damping arrangement in response to the determination that the head is inoperative. A movement of the head while the head is inoperative is sensed. The damping arrangement is used in response to the sensing step to exert a force upon the head to thereby damp the movement, a magnitude of the force being dependent upon a parameter of the movement.