Laser Tracker Coordinate Sharing for Multi-Tracker Accuracy
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Solution Overview
Problem
The accuracy of position measurement in systems that share a common coordinate system among multiple position measurers is compromised due to errors in the coordinate systems defined by individual laser trackers, particularly when the mutual distance between reflectors is limited, leading to increased angle errors in measurement positions.
Innovation Solution
A position measurement system where one position measurer defines a coordinate system using three coordinate definition targets and shares this information with other position measurers, allowing them to measure points using a correction vector based on their positional relationship, thereby reducing errors and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple laser trackers are installed to measure position coordinates of multiple supporting robots, then measurement efficiency is improved, but coordinate system errors increase due to thermal factors and angle errors
Solution Approach 1:
Multiple laser trackers share a common coordinate system defined by one reference laser tracker, merging their measurement results through coordinate transformation based on mutual positional relationships, thereby maintaining measurement efficiency while reducing coordinate system errors
Solution Approach 2:
A common coordinate system acts as an intermediary between multiple laser trackers, enabling their measurement results to be unified and integrated while compensating for individual tracker errors through coordinate transformation
2Measurement precision
If the mutual distance between reflectors for defining coordinate system is increased, then coordinate system accuracy improves, but thermal deformation and positional stability become problematic
Solution Approach 1:
Each laser tracker measures the positions of three reflectors to create a copied coordinate system based on the reference coordinate system, allowing accurate position measurement without requiring large physical distances between reflectors
Solution Approach 2:
The patent replaces the mechanical requirement of large physical distances between reflectors with computational coordinate transformation methods, using mathematical relationships to achieve accurate positioning without thermal deformation issues
3Ease of operation
If each laser tracker independently defines its own coordinate system, then measurement autonomy is improved, but coordinate system consistency deteriorates due to angle errors and positional deviations
Solution Approach 1:
The reference laser tracker's coordinate system serves as a feedback standard, allowing other laser trackers to adjust and align their measurements through coordinate transformation, maintaining both operational autonomy and system consistency
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
This approach reduces errors in the coordinate system shared among position measurers, enhancing the accuracy of position measurement by using a common coordinate system defined by one position measurer and correcting for positional relationships between measurers.
Implementation Method 1
the position of a reflector provided on each robot is detected by one laser tracker
Implementation Method 2
the position of a reflector provided on each robot is detected by one laser tracker
Data Source
AI summary
An object is to, in a case where it is necessary to share a common coordinate system by a plurality of position measurers, reduce an error in the coordinate system between the position measurers. A position measurement system allows a plurality of laser trackers to share position measurement of a plurality of measurement points. The laser tracker measures three coordinate definition targets for defining a coordinate system of the measurement points, defines a work coordinate system from measurement results of the three coordinate definition targets, and measure the measurement points allocated to the laser tracker using the defined work coordinate system. The other laser trackers and measure the measurement points allocated to the other laser trackers and using correction vectors based on a positional relationship between the laser tracker and the laser trackers and obtained in advance, and the work coordinate system defined by the one laser tracker.