Improved accuracy of capacitive sensor-based micro-angle measurement with angular-to-linear displacement conversion

Area of Science:

• Metrology and Measurement Science
• Precision Engineering
• Sensor Technology

Background:

• Accurate micro-angle measurement is critical for advanced scientific and engineering applications.
• Existing methods face limitations in achieving high precision over large angular ranges.
• Capacitive sensors offer potential for high-resolution displacement sensing.

Purpose of the Study:

• To develop and validate a capacitive sensor-based micro-angle measurement (CSMAM) method.
• To analyze and mitigate error sources in CSMAM systems.
• To optimize CSMAM configurations for 1D and 2D micro-angle measurements.

Main Methods:

• Modeling and analysis of principal and secondary error components in CSMAM.
• Theoretical accuracy analysis of six common CSMAM configurations.
• Implementation of an angular-to-linear displacement conversion using a linear stage and hemisphere decoupler.
• Experimental validation of the optimized CSMAM system.

Main Results:

• Identified and modeled key error components affecting CSMAM accuracy.
• Determined optimal capacitive sensor configurations for 1D and 2D measurements.
• Achieved experimental accuracies of 0.157 arc sec (±900 arc sec range) and 0.052 arc sec (±300 arc sec range).
• Demonstrated error elimination through the proposed conversion method.

Conclusions:

• The optimized CSMAM method significantly enhances micro-angle measurement accuracy.
• The developed technique provides a reliable reference for future CSMAM designs.
• High-accuracy CSMAM is suitable for diverse precision engineering applications, including angle metrology and precision stages.