Multi-Stage Servo Calibration Using Single PES Gain Measurement
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Solution Overview
Problem
Multi-stage actuated servo systems in data storage devices face challenges in calibrating microactuators efficiently, leading to unpredictable and unreliable performance due to the need for precise positional adjustments and long calibration times.
Innovation Solution
A method involving seeking the multi-stage actuated servo system to a selected location, providing a voltage injection to a microactuator, measuring a position error signal (PES), determining a gain for the microactuator based on the PES without additional signal injection, and applying the gain to improve calibration efficiency and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods with multiple signal injections are used, then measurement precision may be improved, but calibration time increases significantly
Solution Approach 1:
The patent extracts and eliminates the unnecessary second signal injection step from the traditional calibration process. By using only a single voltage injection to the microactuator and measuring the resulting PES, the method removes redundant measurements while maintaining calibration accuracy through direct gain calculation from the injected signal and measured error.
Solution Approach 2:
The patent performs preliminary seeking to a known location using the first stage actuator before calibration. This preliminary positioning ensures the system starts from a known state, allowing accurate gain determination from the single voltage injection without requiring multiple injections or complex reference measurements.
2Measurement precision
If multiple signal injections are performed during calibration, then gain determination accuracy may be improved, but the complexity of the calibration process increases
Solution Approach 1:
The patent removes the complex multi-signal injection procedure and replaces it with a single voltage injection method. The gain is determined directly from the relationship between the injected voltage and the measured PES, eliminating the need for multiple injections, signal processing, and complex calculations.
Solution Approach 2:
Instead of injecting multiple position signals and calculating gain from ratio comparisons, the patent inverts the approach by injecting a single voltage signal and determining gain directly from the resulting PES measurement, simplifying the entire calibration workflow.
3Reliability
If traditional calibration procedures are used, then thorough calibration may be achieved, but productivity during calibration decreases
Solution Approach 1:
The patent extracts the essential calibration function and performs it through a single voltage injection and PES measurement, rather than using traditional multi-step procedures. This maintains the reliability of microactuator performance calibration while dramatically increasing calibration throughput by eliminating unnecessary steps.
Solution Approach 2:
The patent skips the traditional multi-injection calibration sequence and rushes through the calibration process using a single injection. By directly calculating gain from one measurement event, the method maintains calibration reliability while achieving much higher productivity and faster calibration cycles.
Data Source
AI summary
Systems and methods are disclosed for calibrating actuators in a multi-stage servo system. In certain embodiments, a method may comprise performing a calibration process on a multi-stage actuated servo system, including: seeking the multi-stage actuated servo system to a selected location, via a first stage actuator; providing a first voltage injection to a first microactuator of the multi-stage actuated servo system; measuring a first position error signal (PES) of the multi-stage actuated servo system; determining a first gain for the first microactuator based on the first PES, without adding a signal injection to the first PES; and applying the first gain to the first microactuator.