3D Workpiece Reposing Using Weighted Boundary Error Alignment
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Solution Overview
Problem
In automated manufacturing systems, there is a need for automatic posing of workpieces relative to reference models or vice versa, especially considering workpieces of arbitrary size and shape, to ensure proper positioning and orientation during manufacturing, inspection, or packaging processes.
Innovation Solution
A computer-implemented method and apparatus that iteratively compute an error measure based on error indicators and perform spatial transformations to correctly pose a workpiece relative to a reference model, using a 3-dimensional boundary representation and weighting functions to prioritize error reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an iterative procedure with error measure computation and spatial transformation is used to repose the workpiece, then the positioning accuracy is improved, but the computational time and processing complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-computing the 3-dimensional boundary representation of the workpiece and storing it in a database before the actual posing operation. This pre-processing step allows the iterative procedure to work with pre-prepared data structures, reducing computational time during the actual posing operation while maintaining positioning accuracy through the use of pre-calculated geometric information.
Solution Approach 2:
The patent segments the posing problem into distinct computational stages: obtaining the 3-dimensional boundary representation, computing error indicators between boundary points, calculating error measures, and performing spatial transformations. This segmentation allows each stage to be optimized independently and enables parallel processing of error indicator computations for multiple boundary points, thereby reducing overall computational time while maintaining accuracy.
2Manufacturing precision
If a weighting function is applied to prioritize error indicators based on their position relative to the boundary, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by introducing a weighting function that assigns different weights to error indicators based on their local position relative to the workpiece boundary. Error indicators closer to the boundary receive higher weights, while those farther away receive lower weights. This local differentiation improves manufacturing precision by focusing computational effort on critical regions without requiring complex global adjustments to the entire posing algorithm.
3Adaptability or versatility
If the 3-dimensional boundary representation is obtained through imaging systems like laser scanners, then the adaptability to arbitrary workpiece shapes is improved, but the measurement time and equipment complexity increase
Solution Approach 1:
The patent applies copying by creating a digital 3-dimensional boundary representation (a virtual copy) of the physical workpiece using imaging systems. This digital copy captures the complete geometric information of arbitrary workpiece shapes without requiring physical contact or complex mechanical measurement apparatus. The digital boundary representation can then be stored and reused for multiple posing operations, reducing the need for repeated physical measurements and simplifying the overall system complexity.
Data Source
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AI summary
The present application provides means for reposing relative to each other a 3-dimensional workpiece (WP) and a 3-dimensional model of the workpiece relative to each other. A computer implemented method in accordance therewith comprises: obtaining a 3-dimensional boundary representation (RI) of a boundary defining volume for the workpiece; repeating steps of an iterative procedure until a stop criterion is complied with; wherein each iteration of the iterative procedure comprises: computing (S3) an error measure based on a plurality of error indicators performing (S4) a spatial transformation to reduce the error measure; wherein each error indicator is indicative for a distance between a reference position of the 3-dimensional representation of a reference model of the workpiece and a position of the 3-dimensional boundary representation of the workpiece and wherein the error indicator is weighted according to a weighting function that assigns a smaller weight to an error indicator if the reference position is inside the boundary defining volume than to an error indicator having the same magnitude if the reference position is outside the boundary defining volume.