Kinematic characterization and error compensation of a legacy piezoelectric actuator via sub-pixel optical metrology

Abstract

Optical and micro-mechanical systems often outlive their original manufacturer specifications, necessitating re-characterization to maintain their operational tolerances. This study presents a non-invasive sub-pixel optical metrology methodology to evaluate and compensate for the kinematic degradation of a legacy piezoelectric actuator. While the hardware possesses a theoretical minimum step resolution of 30 nm, environmental and optical limitations establish a practical metrological noise floor of ±0.22 µm. By analyzing the first-order differences of sequential actuation bursts, a discrete error profile was generated. This profile was utilized to construct a pre-compensation Look-Up Table (LUT), effectively mitigating stiction and momentum overshoot. The findings demonstrate that sub-pixel image analysis is a viable tool for extending the operational lifecycle of orphaned laboratory equipment, provided that compensatory data is strictly bounded by the empirical limits of the optical tracking system.