MIMO Decoupler for Multi-Actuator Head Positioning
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Solution Overview
Problem
Data storage devices face challenges in accurately positioning heads over disk surfaces due to coupling disturbances between multiple actuators, which affect the precision and efficiency of seek and track operations.
Innovation Solution
A Multiple Input Multiple Output (MIMO) control system is implemented, utilizing nominal and adaptive decouplers to attenuate coupling disturbances across actuators, with nominal decouplers generated based on measured coupling transfer functions and adaptive decouplers further compensating for residual disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple actuators are used to access multiple disk surfaces, then productivity is improved, but coupling disturbances occur that worsen positioning precision
Solution Approach 1:
The patent introduces a decoupler as an intermediary component in the control system that processes control signals before they reach the actuators. The decoupler uses measured coupling transfer functions to calculate and apply compensation signals that counteract the coupling disturbances between actuators, thereby maintaining positioning precision while enabling multiple actuators to operate simultaneously.
Solution Approach 2:
The patent implements a feedback mechanism where coupling disturbances are measured between actuators and this measurement is used to adjust control signals. The measured coupling transfer functions are used to configure decouplers that continuously compensate for coupling effects, creating a closed-loop system that maintains precision despite the presence of multiple actuators operating in parallel.
2Manufacturing precision
If coupling disturbances are compensated using control signals, then positioning precision is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by measuring and storing coupling transfer functions before normal operation begins. These pre-measured transfer functions are then used to pre-configure the decouplers, so that during actual operation, the compensation is already built into the control system architecture, reducing the real-time computational burden and simplifying the control logic.
Data Source
AI summary
A data storage device is disclosed comprising a first actuator configured to actuate a first head over a first disk surface, and a second actuator configured to actuate a second head over a second disk surface. A seeking control signal is generated and used to control the first actuator to seek the first head over the first disk surface. The seeking control signal is filtered with a decoupler to generate a decoupler control signal, wherein the decoupler comprises a nominal decoupler and an adaptive decoupler. A tracking control signal is generated based on the decoupler control signal, and the tracking control signal is used to control the second actuator in order to access the second disk surface using the second head.