Calibration algorithm of contact contour scanner system

Abstract

The principle of the contact contour scanner is to use the length sequence returned by the encoder and the rotation angle of the rotating platform to determine the contour coordinates of the object to be measured. Since the starting point of the detection hook does not coincide with the center of the rotating platform，it leads to the contour drawn directly from the measured data is not accurate. In order to solve this error, this paper proposes a method that does not need to establish the precise error model of the system, but to obtain system parameters by using the data obtained from the square calibration plate with known measurement size, and then calibrates the contour coordinates online. The measurement process was simulated through programming and the parameters obtained were compared with the ideal parameter values. The simulation data showed that the algorithm could control the measurement error below 0.5 mm and the angle error below 0.1°, which met the accuracy requirements of the equipment and could restore the real contour of the graph under test.

Keywords

• contact measurement
• coordinate calibration
• least squares
• fitting
• the calibration model