Adaptive Head Positioning Control for Disk Drive Disturbance Suppression
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Solution Overview
Problem
Existing head positioning control methods for disk devices struggle to adapt to a wide range of disturbance frequencies without affecting the control characteristics, leading to compromised positioning accuracy and read/write performance, especially in mobile equipment exposed to various vibrations.
Innovation Solution
A head positioning control method that computes an estimated position error and generates state information using both actuator and disturbance models, allowing for adaptive adjustment of estimated gains based on disturbance frequency to maintain control characteristics and improve follow-up performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the estimated gain is increased to improve follow-up performance to disturbances, then the disturbance suppression range is widened, but the disturbance model and the original controller model interfere with each other, changing the control characteristics
Solution Approach 1:
The patent segments the control system into two independent models: the original controller model and the disturbance model. By separating these models, the system can independently adjust the disturbance suppression range without affecting the original control characteristics. The disturbance model operates as an independent observer that estimates disturbance frequency and adjusts gains without interfering with the primary controller's stability and performance.
Solution Approach 2:
The patent introduces a disturbance observer as an intermediary component between the controller and the disturbance. This observer estimates the disturbance frequency and provides compensation signals without directly modifying the original controller's behavior. The intermediary structure allows the system to adapt to various disturbance frequencies while maintaining the original control characteristics intact.
2Adaptability or versatility
If the disturbance model and original controller model are separated to maintain control characteristics, then the adaptability to wide range of disturbance frequencies is improved, but the system complexity increases
Solution Approach 1:
The patent merges the disturbance observer with the existing controller structure, allowing both functions to operate within a unified control loop. The disturbance model is integrated as an additional observer component that shares the same state estimation framework, reducing the need for completely separate hardware or control loops and thereby limiting the increase in system complexity.
Data Source
AI summary
A positioning control device executes disturbance observer control having a disturbance suppression function, wherein changes of control characteristics are prevented even if the disturbance frequency is suppressed. When a control value of an actuator is computed using estimated gains of the actuator and estimated gains of disturbance according to an estimated position error by disturbance observer control including a model of the actuator and model of the disturbance, the disturbance frequency is estimated according to the estimated position error, and the estimated gains of the actuator and the estimated gains of the disturbance, corresponding to the disturbance frequency, are changed. Therefore appropriate observer control according to the disturbance frequency can be implemented.