Calibration of sensor system used in ultra-precision form measuring instrument

Abstract

Static and dynamic calibration methods of sensor system used in ultra-precision form measuring instrument are investigated. The nonlinear error of sensor system are corrected through static calibration, and the nonlinear characteristic of sensor system is obtained with a piezo nanopositioning stage, then the nonlinear characteristic is stored in a computer in the form of error correction function, while the sensor system works, according to the established error correction function, corrected value of nonlinear error that correspond to the measured point is to be taken out automatically, and the actual measurement data could be compensated by real-time, namely, the dynamic compensation model for nonlinear error could be established. Especially, if the position of measurement data point is not the same as that pre-stored in computer, corrected value could be obtained using linear interpolation. Dynamic calibration of sensor system is performed using the elliptical standards, and in this case the calibration status of sensor system is consistent with its normal measurement status.