Static calibrations of LVDT sensors for traceable gauge blocks

Abstract

Linear variable differential transformer (LVDT) sensors are usually used in precision measurement system for dimensional displacement measurements, especially in long gauge block comparator or gauge block. In order to ensure the accuracy of the LVDT sensor, the research provides static calibration methods to measure the displacement linearity to within ± 12mm. Our experiment structures include a laser interferometer and mechanical devices to setup optical alignments on SIP universal measuring machine. The experiment results show the read values from LVDT sensor and laser interferometer, and the correction values are defined as the read values of LVDT subtracted from the ones of laser interferometer. These corrections were calculated statistically as regression and residual analysis. Statistical results show that correctional error is 0.04 mm in short-term operations, and the displacement linearity is -0.016 mm /1 mm. For precision measuring systems, LVDT sensors should be calibrated periodically and the research results could provide both a static calibration method and plotting linearity curves for users’ references.