High-accuracy interferometric calibration system for 1-D displacement transducers

Accurate calibration of tactile linear transducers is critical for ensuring traceability and reliability in precision measurement applications, particularly in fields such as advanced manufacturing, metrology, and scientific instrumentation. To meet the growing demand for faster and more accurate calibration, a novel purpose-built interferometric measurement instrument has been developed and implemented. The system features a high-precision 200 mm vertical linear stage and a heterodyne laser interferometer to provide repeatable and accurate measurements, with methods to minimize cosine error and Abbe offset. All components are integrated into a PC-controlled system that automates the measurement process. The setup includes real-time compensation for environmental influences, like air pressure, temperature, and humidity. Overscan routines and unidirectional motion during inward and outward measurements improve repeatability, while results are averaged over multiple runs to reduce uncertainty. This instrument enables traceable, high-resolution calibration in a controlled laboratory environment, supporting the increasing need for dependable dimensional metrology in high-precision applications. For calibration of high-accuracy, gravity-actuated 1-D displacement transducers with measurement ranges in the millimetre to centimetre scale, state-of-the-art expanded uncertainty of U = Q[12.6 nm; 1.9 × 10⁻⁷ l] is achieved.