Interferometric Metrology for End Tool Position and Orientation
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Solution Overview
Problem
Existing metrology systems for movement systems, such as robots, face limitations in accuracy and efficiency for tracking position and orientation, particularly in achieving high reliability, repeatability, and speed for workpiece measurements and manufacturing processes.
Innovation Solution
A metrology system that incorporates a light beam source configuration and a sensor configuration with light beam sensors to determine the position and orientation of an end tool, using coherent light sources and diffractive optical elements to produce multiple light beams for precise measurement, allowing for improved accuracy and reduced complexity in determining the position and orientation of the end tool within a movement volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional photogrammetry methods are used to determine position and orientation, then the system structure is simpler, but the measurement precision and reliability are lower due to aberration errors and reduced sensitivity to orientation
Solution Approach 1:
The patent replaces traditional photogrammetry optical systems with a laser-based interferometric measurement system. Coherent light sources (lasers) and interferometric sensors detect position and orientation through interference patterns, eliminating photogrammetry's inherent aberration errors and improving orientation sensitivity while maintaining system compactness
Solution Approach 2:
The patent changes the fundamental measurement parameter from intensity-based photogrammetry to phase-based interferometry. By using coherent light waves and detecting interference patterns, the system achieves higher precision in determining both position and orientation parameters simultaneously
2Measurement precision
If calibration techniques are used to improve positioning accuracy, then the measurement precision improves, but the loss of time increases due to repeated calibration procedures
Solution Approach 1:
The patent implements self-calibration through the interferometric measurement system. The system automatically determines its own position and orientation parameters by analyzing interference patterns from multiple coherent light sources, eliminating the need for manual calibration procedures and achieving continuous high-precision measurement without time loss
Solution Approach 2:
The system uses real-time interferometric feedback from multiple sensors to continuously monitor and adjust position and orientation measurements. This closed-loop approach maintains high precision without requiring periodic calibration interruptions
3Manufacturing precision
If mechanical position sensors like rotary encoders are used, then the device complexity is lower, but the manufacturing precision is limited to approximately 100 microns due to mechanical stability constraints
Solution Approach 1:
The patent replaces mechanical rotary encoders with optical interferometric sensors. The system uses coherent light sources and interference pattern analysis to measure position and orientation, achieving sub-micron precision that far exceeds the 100-micron limit of mechanical systems while eliminating mechanical stability constraints
Solution Approach 2:
The patent transitions from one-dimensional mechanical angle measurements to multi-dimensional optical interference measurements. By using multiple coherent light sources and sensors, the system simultaneously measures position and orientation in three-dimensional space with high precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides higher accuracy and reliability in determining the position and orientation of the end tool, outperforming traditional methods like photogrammetry by being more sensitive to orientation and avoiding aberration errors, while also being compact and cost-effective.
Implementation Method 1
using coherent light sources and diffractive optical elements to produce multiple light beams for precise measurement
Implementation Method 2
using coherent light sources and diffractive optical elements to produce multiple light beams for precise measurement
Data Source
AI summary
A metrology system is provided for use with a movement system that moves an end tool (e.g., a probe). The metrology system includes a sensor configuration, a light beam source configuration and a processing portion. The sensor configuration comprises a plurality of light beam sensors. The light beam source configuration directs light beams to the light beam sensors of the sensor configuration. One of the light beam source configuration or the sensor configuration is coupled to the end tool and/or an end tool mounting configuration of the movement system which moves the end tool. The light beams that are directed to the light beam sensors cause the light beam sensors to produce corresponding measurement signals. A processing portion processes the measurement signals from the light beam sensors which indicate the position and orientation of the end tool.