Optical Disk Drive Ball Auto-Balance Control Method
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-speed optical disk drives experience instability and noise due to vibrations caused by unbalanced spindle motors, with existing auto-balancing systems (ABS) having manufacturing tolerance issues that prevent a universal rotating speed controlling curve, leading to ineffective vibration damping.
Innovation Solution
A method for controlling the ball auto-balancing system (ABS) involves setting an accelerating and decelerating range for the spindle motor between specific RPMs, repeatedly driving the rotational member to accelerate and decelerate, measuring central error values, and adjusting the range based on these values to balance the balls to the best vibration damping position, applicable across all optical disk drives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed rotating speed controlling curve is used for the ABS, then the ball balancing can be optimized for a specific drive, but manufacturing tolerances cause resonance variations that prevent universal application, leading to increased vibrations
Solution Approach 1:
The patent implements a dynamic rotating speed controlling curve that is generated in real-time based on measured resonance frequencies. Instead of using a fixed predetermined curve, the system automatically adjusts the accelerating and decelerating ranges according to the specific resonance characteristics of each optical disk drive, enabling both precise ball balancing and universal adaptability across different drives with varying manufacturing tolerances
Solution Approach 2:
The system changes the operating parameters (rotating speed ranges) based on measured resonance frequencies. By dynamically adjusting the accelerating and decelerating speed ranges according to the specific resonance characteristics of each drive, the system achieves optimal ball balancing performance across different optical disk drives with varying manufacturing tolerances
2Speed
If the spindle motor rotates at high speed, then data reading and writing speed is improved, but large vibrations occur due to unbalance, causing servo signal instability and noise
Solution Approach 1:
The system performs preliminary ball balancing through automatic acceleration and deceleration cycles before the optical disk drive operates at high speeds. By pre-positioning the balls at optimal balancing locations during the accelerating and decelerating phases, the system eliminates vibrations and noise that would otherwise occur during high-speed data reading and writing operations
Solution Approach 2:
The auto-balancing system uses the spindle motor's own rotating motion to achieve ball balancing without requiring external balancing equipment. The system automatically detects resonance frequencies, generates appropriate speed control curves, and positions the balls during normal operation, making the balancing process self-contained and integrated into the drive's operational cycle
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 method effectively balances the balls to reduce vibrations and ensure stable operation across different optical disk drives, adjusting the accelerating and decelerating range to account for manufacturing variations and improve vibration damping.
Implementation Method 1
when the rotating speed of the spindle motor is greater than a critical speed, the balancing mass automatically rolls to a balancing position with unbalance due to an unbalance disc
Implementation Method 2
the vibrations produced when the spindle motor rotates at the high speed can be effectively reduced
Data Source
AI summary
A method for controlling a ball auto-balancing system of an optical disk drive is provided. A rotational member is fixed on a rotating axis of an optical disk drive and rotates synchronously therewith. A spindle motor drives the rotational member to accelerate and decelerate within the rotating speed range at least twice. When the spindle motor accelerates and decelerates for many times, if the measured central error value is greater than the last measured one, the accelerating and decelerating range is adjusted.