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 high-precision measurements in optics and aerospace.
• Geometric errors significantly degrade 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 new error sensitivity evaluation index that considers workpiece surface profiles.
• To enhance 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 novel effective working distance error (WDEe) index for sensitivity evaluation.

Main Results:

• The proposed method achieved compensated measurement results of 3.189 µm, closer to the reference value (2.985 µm) than conventional methods (3.320 µm).
• The new comprehensive index replaced six traditional volumetric error indexes.
• Demonstrated improved sensitivity analysis and error compensation effectiveness.

Conclusions:

• The developed error modeling and analysis approach effectively enhances optical profilometer performance.
• The proposed WDEe index offers a more sensitive and comprehensive evaluation of measurement errors.
• This method improves the efficiency and accuracy of error compensation for precision instruments.