Study on a novel method for refractive index compensation of laser measuring system on the ultraprecision machine tools

摘要

Research on the precision in-process measuring system with high measuring velocity is very important to the development of ultraprecision machine tools. One of the main factors blaking the further enhancement of measuring accuracy of two-frequency laser is the changing of refractive index with environment, which produces the change of the wavelength, the measuring basis. The general method for solving the problem is using atmospheric parameter compensator. The method ocmputes the refractive index using the atmospheric parameter compensator. The general method for solving the problem is using atmospheric parameter compensator. The method computes the refractive index using the atmospheric parameters, which is affected by the accuracy of atmospheric sensor, and the cost of the system is also high. This paper presents a new method. It uses a additional calibration optical path, which is put on the machine together with measuring optical path, to compensate the changing of refractive index. The influence of the refractive index on both path are similar, therefore it can be expected that the error caused by the changing of refractive index can be well compensated. The method can also compensate the optical distnace change caused by the mateiral temperature.