Tri-Stage Actuator Pseudo Feature Balancing
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Solution Overview
Problem
Current disk drive suspensions with dual-stage actuation face limitations in achieving high servo bandwidths required for increased data density and tracks per inch, as they struggle to balance the mass and stiffness of microactuators effectively, leading to suboptimal positioning of head sliders over data tracks.
Innovation Solution
A disk drive suspension with tri-stage actuation and a pseudo feature integrally formed on the trace gimbal assembly to balance the mass and stiffness of a single microactuator, eliminating the need for a separately manufactured counterbalance and simplifying the manufacturing process, while allowing for finer control with multiple PZT actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single microactuator is mounted on the trace gimbal assembly, then fine control of head slider positioning is achieved, but mass and stiffness imbalance occurs leading to suboptimal servo performance
Solution Approach 1:
A pseudo feature is integrally formed on the trace gimbal assembly to provide counterbalancing mass and stiffness that offsets the imbalance caused by the single microactuator. This integral counterbalance structure eliminates the need for separate counterweights while restoring dynamic balance for optimal servo performance
2Stability of the object's composition
If a separately manufactured counterbalance is used to balance the microactuator, then mass and stiffness balance is achieved, but device complexity and manufacturing steps increase
Solution Approach 1:
The counterbalance function is merged into the trace gimbal assembly by integrally forming the pseudo feature during the same manufacturing process. This eliminates separate counterbalance components and assembly steps, reducing device complexity while maintaining mass and stiffness balance
3Ease of operation
If dual-stage actuation is used, then coarse and fine positioning is achieved, but servo bandwidth is insufficient for high data density requirements
Solution Approach 1:
The system transitions from dual-stage to tri-stage actuation by adding a third actuator stage on the trace gimbal assembly. This additional stage with its associated pseudo feature provides enhanced dynamic response and higher servo bandwidth while maintaining the hierarchical positioning capability across all three stages
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 tri-stage actuation with integrally formed pseudo features enhances the servo bandwidth, enabling more precise alignment and movement of the head slider over the data track, addressing the limitations of existing dual-stage designs and supporting higher data density and track density requirements.
Implementation Method 1
A piezoelectric element, sometimes referred to simply as a PZT, is often used as the microactuator motor
Data Source
AI summary
A dual stage actuated suspension has a first piezoelectric microactuator on the trace gimbal assembly (TGA), and a pseudo feature located laterally opposite the microactuator. The pseudo feature is formed integrally with the TGA from at least one of the base metal layer, the insulative layer, and the conductive layer that make up the TGA. The pseudo feature helps to balance the suspension. The suspension can optionally have a second microactuator located proximal of the first microactuator in order to perform coarser positioning than the first microactuator, such that the suspension is a tri-stage actuated suspension.