Spindle Active Braking for Faster Actuator Arm Burnishing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing data storage devices face inefficiencies in the deceleration process of spindles and actuator arms, particularly in processes like burnishing, which are lengthy and increase manufacturing costs due to the need for incremental speed adjustments.
Innovation Solution
Implementing an active brake dual RPM (ABDR) process that controls the actuator arm and spindle motor by applying a driver voltage out of phase with the back electromotive force (BEMF) voltage to rapidly decelerate the spindle, allowing simultaneous control of both components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If incremental speed adjustments are used to decelerate the spindle, then the deceleration process is controlled and stable, but the processing time increases significantly
Solution Approach 1:
The patent changes the electrical parameter relationship between driver voltage and BEMF voltage from in-phase to out-of-phase, fundamentally altering the motor's operational state from propulsion to braking. This parameter change enables rapid deceleration while maintaining controlled reduction of spindle speed, resolving the contradiction between controlled deceleration and processing time.
Solution Approach 2:
The patent employs periodic switching between different voltage phase relationships (in-phase for acceleration/maintenance, out-of-phase for deceleration) to achieve both controlled speed reduction and time efficiency. The control circuitry periodically adjusts the voltage phase based on the deceleration requirements, combining stability with speed.
2Loss of time
If the spindle is decelerated rapidly, then the processing time is reduced, but the control complexity increases
Solution Approach 1:
The patent utilizes feedback from the BEMF voltage to dynamically adjust the driver voltage phase. The control circuitry continuously monitors the BEMF signal and uses it as feedback to maintain the out-of-phase relationship during deceleration, enabling rapid controlled deceleration without excessive complexity. The feedback mechanism automatically adapts to changing spindle speeds.
Solution Approach 2:
The BEMF voltage, which is naturally generated by the motor during operation, is utilized as a reference signal for the control circuitry. This self-service approach eliminates the need for external reference signals or complex sensing systems, reducing control complexity while enabling precise rapid deceleration through the out-of-phase voltage relationship.
3Productivity
If the actuator arm moves at high velocity, then the productivity is improved, but the risk of head wear increases
Solution Approach 1:
The patent applies preliminary braking action by establishing the out-of-phase voltage relationship before the actuator arm completes its movement. The spindle deceleration is initiated in advance during the actuator arm's high-velocity travel, ensuring that by the time the head reaches the disk surface at high speed, the spindle is already at a reduced speed, minimizing head wear while maintaining productivity.
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 significantly reduces processing time by up to four times, thereby decreasing manufacturing costs and enhancing processes like burnishing by ensuring rapid and controlled deceleration without head wear.
Implementation Method 1
controlling a driver voltage of the spindle motor to be out of phase relative to a back electromotive force (BEMF) voltage of the spindle motor
Implementation Method 2
applying an active brake to decelerate the spindle by controlling a driver voltage of the spindle motor to be out of phase relative to a back electromotive force (BEMF) voltage of the spindle motor
Data Source
AI summary
A data storage device comprises a disk; a spindle on which the disk is mounted; a spindle motor that rotates the spindle; an actuator arm configured with a recording head; and an actuator that rotates the actuator arm about a pivot to move the actuator arm radially across a disk surface. Control circuitry controls the actuator to move the actuator arm across the disk surface while simultaneously applying an active brake to decelerate the spindle by controlling a driver voltage to be out of phase with a back electromotive force (BEMF) voltage of the spindle motor.