Modeling and analysis of measurement error for a four-axis optical profilometer

Area of Science:

• Metrology
• Optical Engineering
• Mechanical Engineering

Background:

• Multi-axis optical profilometers are crucial for precision measurements in optics and aerospace.
• Geometric errors significantly affect the accuracy of these instruments.
• Existing error analysis methods may lack comprehensive sensitivity evaluation.

Purpose of the Study:

• To develop an advanced approach for error modeling and analysis of a four-axis optical profilometer.
• To introduce a novel error sensitivity evaluation index that considers workpiece surface profiles.
• To improve the efficiency and effectiveness of error compensation in optical profilometry.

Main Methods:

• Utilized Multi-Body System (MBS) theory and the Homogeneous Transformation Matrix (HTM) method.
• Established a measurement error model encompassing forty-five geometric errors.
• Proposed a new index, effective working distance error (WDEe), for sensitivity evaluation.

Main Results:

• Comparative experiments showed compensation using the proposed method yielded results closer to reference values (3.189 µm vs. 2.985 µm).
• The new method outperformed conventional approaches (3.189 µm vs. 3.320 µm).
• The WDEe index replaced six traditional volumetric error indexes, enhancing analysis.

Conclusions:

• The proposed error modeling and compensation approach effectively improves optical profilometer performance.
• The novel WDEe index offers a more sensitive and comprehensive evaluation of measurement errors.
• This method enhances error compensation efficiency and accuracy in precision metrology.