A Noncontact Method for Calibrating the Angle and Position of the Composite Module Array

Abstract

Freeform surface is one of the research focuses in the measurement field. A composite module is composed of a plane and rotating paraboloid. The composite module array can identify 21 geometric errors of the machine tool in a wide range, which is composed of several composite modules. Eliminating the error of the array itself is of great significance for improving measurement accuracy. For this reason, this paper proposed a noncontact method for calibrating the angle and position of the composite module array. This paper used a self-developed angle sensor to access corresponding information and established the mathematical model according to the freeform surface’s geometric characteristics to achieve calibration. In addition, the influence of array placement error on calibration was analyzed. The experimental results showed that the angle repeatability was within 0.4″ around the X-axis and within 0.3″ around the Y-axis, and the position repeatability was within 0.4 µm in the X direction and within 0.7 µm in the Y direction. The measurement comparison experiments with high-precision laser interferometer and uncalibrated array verified the correctness of the experimental results. This method provides an important reference for practical application and freeform surface array calibration, and creates conditions for the implementation of machine tool error detection.

Effect of Wheel Path in Raster Grinding on Surface Accuracy of an Off-Axis Parabolic Mirror

“…The surface accuracy of the machined surface was guaranteed via finish grinding, so the off-axis parabolic surface after finishing was detected. A three-coordinate measuring machine (PRISMO, ZEISS, Berlin, Germany) was used to realize the contact measurement of the surface accuracy [33,34]. By controlling the probe to scan the entire machining surface, the three-dimensional coordinate point cloud data of the actual machining surface was obtained.…”