High-Speed Optical Metrology for End-Tool Position and Orientation
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Solution Overview
Problem
Existing robot systems face limitations in achieving high accuracy and reliability for position and orientation determination, particularly in manufacturing and workpiece inspection, due to factors such as encoder performance and mechanical stability, which can result in inadequate calibration techniques that are time-consuming and lack desired precision.
Innovation Solution
A metrology system is integrated with a movement system, utilizing a light beam source configuration and sensors to determine the position and orientation of an end tool with enhanced accuracy, employing coherent light sources and diffractive optical elements to produce multiple light beams that are directed to fixed sensors, allowing for precise measurement spot detection and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration techniques are used to determine position and orientation, then the system can operate with standard components, but the accuracy and reliability are insufficient
Solution Approach 1:
The patent replaces mechanical position sensing systems (encoders, mechanical scales) with an optical measurement system using light beams and photodetectors. The light beam system provides direct optical measurement of position and orientation without mechanical contact, achieving higher accuracy and reliability by eliminating mechanical error sources such as encoder resolution limits and mechanical wear.
Solution Approach 2:
The patent creates an optical copy or representation of the mechanical system's position through light beam trajectories. By measuring the position and orientation of light beams that follow the same paths as mechanical components, the system obtains precise positional information without directly measuring the mechanical components themselves, thereby improving measurement accuracy.
2Measurement precision
If traditional position sensors like rotary encoders are used, then the system structure remains simple, but the positioning accuracy is limited to approximately 100 microns
Solution Approach 1:
The patent substitutes mechanical rotary encoders with an optical beam system. Instead of using mechanical components with inherent resolution limits (100 microns), the system uses light beams whose position can be detected with much higher precision by photodetectors, achieving sub-micron accuracy while accepting increased optical system complexity.
3Measurement precision
If calibration procedures are performed to improve accuracy, then measurement precision increases, but significant time is required for the calibration process
Solution Approach 1:
The optical measurement system performs self-calibration by continuously monitoring light beam positions during normal operation. The system automatically adjusts and refines measurement parameters without requiring external calibration equipment or procedures, eliminating time-consuming manual calibration processes while maintaining high measurement precision.
4Reliability
If comprehensive sensor coverage is used to ensure accuracy for all orientations, then measurement reliability improves, but the system complexity and cost increase
Solution Approach 1:
The patent uses a universal optical measurement approach where light beams serve multiple functions: they define measurement planes, provide position references, and enable orientation determination simultaneously. This multi-functional optical system achieves comprehensive coverage for all orientations without requiring separate specialized sensors for each measurement task, reducing overall system complexity.
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 improved accuracy and reliability in determining the position and orientation of the end tool, offering higher precision than conventional methods, with reduced complexity and cost, and does not occupy the working volume, enabling more efficient manufacturing and inspection processes.
Implementation Method 1
The light beam source configuration is configured to direct light beams to light beam sensors of the sensor configuration to indicate a position and orientation of the light beam source configuration
Implementation Method 2
employing coherent light sources and diffractive optical elements to produce multiple light beams that are directed to fixed sensors
Data Source
AI summary
A metrology system is provided for use with a movement system that moves an end tool. The metrology system includes a sensor configuration, a light beam source configuration and a processing portion. The light beam source configuration directs light beams to light beam sensors to indicate a position and orientation of the light beam source configuration. In a high speed operating mode (e.g., an alternative to a standard speed operating mode), the metrology system determines a region of interest (“ROI”) for each light beam sensor of a set of light beam sensors, wherein each ROI includes a measurement spot produced by a light beam. Measurement signals are processed resulting from the ROIs, and a position and orientation of the light beam source configuration is determined. In various implementations, the ROIs are determined (e.g., including position and/or size, etc.) based at least in part on position information from the movement system.