Hard Disk Head Retraction Control via Acceleration Frequency Analysis
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Solution Overview
Problem
Portable devices with built-in hard disk drives face challenges in accurately determining when to retract the magnetic head due to shock or vibration, leading to potential damage and increased power consumption, as existing acceleration sensors can cause unnecessary retraction and decrease user-friendliness.
Innovation Solution
An information processing apparatus with a hard disk drive, acceleration sensor, and a determination section that analyzes low and high frequency components of acceleration data to decide on head retraction, and a threshold value adjustment mechanism based on user inputs and device states, such as lid closure, to minimize unnecessary retraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the magnetic head is retracted when acceleration exceeds a predetermined level, then the magnetic disk is protected from damage, but the head may be unnecessarily retracted during normal operations such as keyboard pressing or lid closing, decreasing user-friendliness
Solution Approach 1:
The system applies preliminary anti-action by detecting the specific cause of acceleration before taking protective action. The determination section analyzes whether acceleration is caused by shock (requiring head retraction) or normal operations like keyboard pressing and lid closing (not requiring retraction). This selective detection prevents unnecessary head retraction while maintaining protection against actual shocks, thus resolving the contradiction between reliability and ease of operation
Solution Approach 2:
The system changes parameters by analyzing different characteristics of acceleration data. Instead of using a simple threshold comparison, the determination section examines patterns and characteristics of acceleration to distinguish between harmful shock and normal operations. This parameter-based differentiation allows the system to maintain appropriate protection while avoiding unnecessary interference with normal device usage
2Measurement precision
If a dedicated shock/vibration processing section is implemented to determine head retraction, then accurate shock detection is achieved, but CPU resources are consumed and power consumption increases
Solution Approach 1:
The determination section serves multiple functions: it analyzes acceleration data for shock detection, distinguishes between shock and normal operations, and controls head retraction decisions. By making this single section multi-functional, the system achieves accurate shock detection without requiring separate dedicated processing sections that would consume additional CPU resources and power, thus resolving the contradiction between measurement precision and energy consumption
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
The solution effectively reduces the likelihood of head contact with the disk surface during vibrations or shocks, improves user-friendliness, and decreases power consumption by accurately determining when to retract the head, thus enhancing the reliability and battery life of portable devices.
Implementation Method 1
an acceleration sensor may be built into the HDD, in many cases, the HDD is merely designed to stop writing data on the disk temporarily
Data Source
AI summary
An information processing apparatus includes a hard disk drive, an acceleration sensor, and a determination section. The hard disk drive is capable of moving a head of the hard disk drive to a data-free landing zone. The acceleration sensor detects acceleration. The determination section obtains a low frequency component from the detected acceleration and determines whether it is necessary to move the head of the hard disk drive to the data-free landing zone based on the low frequency component.