Measurement and compensation method of positioning error in digital height measuring instrument

CHEN Hongfang, LIN Hu, YIN Jianjie
(College of Mechanical Engineering and Applied Electronics Technology,
Beijing University of Technology, Beijing 100124, China)

Abstract: Positioning error is one of the main error sources in the height measuring instrument. In order to increase measurement accuracy, the measuring method and compensating process of positioning error in the digital height measuring instrument were studied. Based on a digital height measuring instrument, positioning error was measured by miniature double plane mirror interferometer SPD of German SIOS corporation. The measurement results were fitted by quadratic polynomial fitting method. With the difference between the original data and the fitting data as the deviant of alignment positioning error, positioning error was compensated. The results of the experiment indicate that positioning error is reduced from 0.009 3 mm to 0.004 6 mm when slide of the height measuring instrument moves upward and positioning error is reduced from 0.010 7 mm to 0.004 8 mm when slide of the height measuring instrument moves downward.
Key words: height measuring instrument; positioning error; laser interferometer