Error analysis of the measurement system due to changes in the position of the light pen

The measurement accuracy of the light pen coordinate measuring system is affected by various error factors, such as camera calibration error, probe calibration error, light pen feature point center calibration error, light pen feature point center projection error, equipment installation error, and human error in the measurement process. One of the main influences on the accuracy of the measurement system is the center projection error of the light pen feature point, which is caused by the change of the light pen position during the measurement process. This paper proposes a method to analyze the projection error of the delicate pen position for the shift in the light pen position, which establishes the projection model of the light pen position according to the measurement range of the system and the camera parameters and analyzes the influence on the measurement accuracy by combining the camera calibration with the change of the light pen position. Through the combination of simulation and experiment to explore the measurement system, the error analysis method can be obtained in the light pen position pitch in -11 ° to 10 ° threshold within the swing in the -7 ° to 6 ° threshold error in 0.001-0.01 mm. The error analysis method is of great significance to the stable measurement of the light pen measurement system to realize higher accuracy.