Residual vibration reduction of white-light scanning interferometry by input shaping

Area of Science:

• Metrology
• Optical Engineering
• Vibration Control

Background:

• White-light scanning interferometry (WLSI) is crucial for high-precision engineering surface metrology.
• Mechanical scanning in WLSI is susceptible to residual vibrations, degrading measurement accuracy and precision.
• Achieving both fast response and high precision is challenging due to vibration amplification with increased proportional gain.

Purpose of the Study:

• To investigate the application of input shaping for mitigating residual vibrations in WLSI systems.
• To enhance the simultaneous achievement of measurement speed and accuracy in WLSI.

Main Methods:

• Input shaping, a signal processing technique, was convolved with a reference signal to design a vibration-reducing input shaper.
• Continuous Wavelet Transform (CWT) was employed to analyze step response data for optimal input shaper design.
• The developed input shaper was implemented on the scanning system of the WLSI.

Main Results:

• The proposed input shaping method significantly reduced residual vibrations in the white-light scanning interferometry system.
• The system demonstrated improved accuracy and precision in surface metrology.
• Faster measurement speeds were achieved without compromising accuracy.

Conclusions:

• Input shaping is a viable and effective strategy for overcoming vibration limitations in WLSI.
• This approach enables simultaneous improvements in measurement speed and accuracy, advancing precision metrology.
• The study provides a practical solution for enhancing the performance of vibration-sensitive optical measurement systems.