Spindle Motor Speed Control for Optical Disc Defect Handling
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Solution Overview
Problem
Current optical storage systems lack an effective control mode for efficiently passing through defects in CDs, leading to errors, mosaics, pauses, or crashes due to inadequate spindle motor speed control in existing CAV, CLV, P-CAV, and zone CLV modes.
Innovation Solution
A method involving a microprocessing unit that detects scrape situations, calculates the longest and accumulation times for passing through defects, and adjusts spindle motor rotation speed accordingly to enhance playback efficiency, using a digital signal processing unit to manage data buffer fullness and adjust spindle motor speed commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotation speed of the spindle motor is increased to pass through defects quickly, then the playing efficiency is improved, but the data transmission accuracy deteriorates due to data errors
Solution Approach 1:
The spindle motor rotation speed is made dynamically adjustable based on defect detection. The system transitions from fixed speed modes (CAV, CLV) to a dynamic control mode where the rotation speed changes in real-time according to the presence and size of defects, allowing high speed during normal playback and controlled speed changes when defects are encountered
Solution Approach 2:
The rotation speed parameter is changed based on defect characteristics. The system measures the time length for passing through defects and uses this information to adjust the rotation speed parameter accordingly, selecting from predefined speed levels that balance playback efficiency with data accuracy
2Speed
If the rotation speed of the spindle motor is randomly changed in CLV mode, then the reading speed is improved, but data errors occur due to unstable data transmission
Solution Approach 1:
The system performs preliminary detection of defects and measures the time length for passing through them before changing the rotation speed. This preliminary action allows the system to plan speed changes in advance rather than making random adjustments, ensuring that speed changes are timed appropriately to maintain data transmission stability
Solution Approach 2:
The system uses feedback from defect detection and time length measurement to control rotation speed changes. The measured time length for passing through defects serves as feedback information that determines the appropriate speed adjustment, creating a closed-loop control system that maintains data transmission stability
3Use of energy by moving object
If a low rotation speed CLV mode is used to save power consumption, then the power efficiency is improved, but serious mosaic or pause situations occur when passing through bigger defects
Solution Approach 1:
The system dynamically adjusts the rotation speed based on defect size and position, allowing the spindle motor to operate at low speed (saving power) during normal playback and automatically increase speed when defects are detected, thereby maintaining playing quality without continuous high power consumption
Solution Approach 2:
When defects are detected, the system applies the skipping principle by increasing the rotation speed to rush through the defect area quickly, minimizing the impact of defects on playback quality while maintaining low speed elsewhere to save power
Data Source
AI summary
A method of use a defect measure to control spindle motor is described. A system gets the defect situation from a CD by referring a maximum time of pass through the defect and a total time of pass through the defect. According the maximum scrape and the scrape of whole CD, the system adjusts a speed of the spindle motor for reducing a bad effect upon the system. When pass through the defect, the system reduce the speed of the spindle motor for saving power consumption.