Real-Time Laser Interference Detection of Mechanical Targets Using a 4R Manipulator

Area of Science:

• Metrology and Measurement Science
• Robotics and Automation
• Optical Engineering

Background:

• Real-time, high-precision detection of mechanical targets during processing is crucial for quality control.
• Existing methods may lack the flexibility and precision required for dynamic manufacturing environments.
• Mobile manipulator systems offer potential for adaptable workpiece positioning and measurement.

Purpose of the Study:

• To develop and validate a laser interferometric sensing measurement (ISM) system integrated with a 4R manipulator for real-time, online workpiece detection.
• To achieve high-precision surface shape restoration and quality index determination during machining.
• To demonstrate the reliability and practicability of the developed system in a workshop setting.

Main Methods:

• Development of a 4R mobile manipulator (MM) system for workpiece positioning.
• Implementation of a laser interferometric sensing measurement (ISM) system with piezoelectric-driven reference plane and CCD sensor.
• Application of advanced interferogram processing techniques, including fast Fourier transform (FFT) with a novel cosine banded cylindrical (CBC) filter and bidirectional extrapolation and interpolation (BEI).

Main Results:

• The system successfully performs real-time, online detection of mechanical targets with high precision.
• Surface shape restoration and quality indexes were obtained, with relative errors for peak-valley and root-mean-square values reaching approximately 0.63% and 1.36%, respectively.
• Comparison with a ZYGO interferometer confirmed the reliability and practicability of the developed ISM system.

Conclusions:

• The integrated 4R MM and ISM system provides a reliable and practical solution for real-time, online precision measurement of mechanical parts.
• The proposed CBC filter and BEI technique enhance interferogram processing accuracy.
• Potential applications include online machining of mechanical parts, shaft-like structures, and annular surfaces.