Laser pointing error analysis and compensation method of low-power laser diode source applied to triangulation...

Area of Science:

• Optics and Photonics
• Metrology and Measurement Science
• Precision Engineering

Background:

• Laser triangulation systems are crucial for accurate distance measurements.
• Pointing drift and dither of laser sources, especially low-power laser diodes (LDs), degrade measurement accuracy.
• Temperature-induced drift and dither in LDs, along with thermal lens deformation, are significant error sources.

Purpose of the Study:

• To analyze the influence factors of laser pointing error in triangulation systems.
• To propose and validate a combined optimization algorithm for compensating laser pointing errors.
• To enhance the absolute accuracy and repeatability of laser triangulation ranging systems.

Main Methods:

• Experimental and simulation-based analysis of laser directivity errors.
• Investigation of temperature drift and dither effects on low-power LDs.
• ZEMAX analysis of measurement errors due to focusing lens thermal deformation.
• Application of polynomial fitting for preliminary temperature drift correction.
• Integration of Kalman filtering for further optimization of measurement results.

Main Results:

• Quantified directivity drifting errors caused by LD temperature changes and dithering.
• Analyzed measurement errors stemming from thermal deformation of the focusing lens.
• Achieved a measurement root mean square error of 0.91 µm after compensation.
• Attained a repeatability of 0.61 µm with the proposed pointing error compensation method.

Conclusions:

• The proposed combined optimization algorithm effectively compensates for laser pointing errors in triangulation systems.
• The method significantly improves both the absolute accuracy and repeatability of measurements.
• This approach is particularly beneficial for low-power laser diode sources susceptible to drift and dither.