In-Process Workpiece Inspection Using CAD Visibility Mapping
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Solution Overview
Problem
Current methods for in-situ dimensional or geometric inspection of parts during manufacturing are inefficient due to the need for multiple sensor acquisitions and increased complexity in cluttered machine tool environments, leading to high calculation times and increased number of acquisitions.
Innovation Solution
A method that determines optimized sensor positions and acquisition sequences by segmenting the CAD model, creating a visibility graph, and defining a path connecting nodes to minimize the number of acquisitions, using a computer with memory and calculation means to record point coordinates and implement the sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensor acquisitions are performed to ensure full coverage of workpiece surfaces in cluttered machine tool environments, then measurement completeness is improved, but calculation time and processing complexity increase
Solution Approach 1:
The patent pre-calculates and stores visibility information in a visibility graph before the actual measurement process. By determining which surfaces are visible from which sensor positions in advance, the system avoids performing complex visibility calculations during multiple acquisitions, thereby reducing calculation time while ensuring complete surface coverage
Solution Approach 2:
The patent segments the workpiece surface into discrete nodes and organizes them in a visibility graph structure. This segmentation allows the system to efficiently determine which nodes are visible from each sensor position without analyzing the entire surface geometry repeatedly, reducing processing complexity during multi-acquisition measurements
2Measurement precision
If the sensor is repositioned multiple times to acquire different surfaces, then surface coverage is improved, but the number of acquisitions and device complexity increase
Solution Approach 1:
The patent pre-determines the optimal sensor positions and acquisition sequence by building a visibility graph that maps which surfaces are visible from which positions. This preliminary planning allows the system to execute a simplified acquisition sequence during actual measurement, reducing device complexity while ensuring complete surface coverage
Solution Approach 2:
The visibility graph serves as an intermediary data structure that simplifies the relationship between sensor positions and workpiece surfaces. Instead of directly computing visibility during each acquisition, the system uses the pre-built visibility graph to quickly determine which surfaces to acquire from which positions, reducing acquisition sequence complexity
Data Source
AI summary
The invention relates to a method for inspecting a part mounted in a manufacturing fixture between two manufacturing operations by means comprising:a sensora robot to hold and move the sensora computer comprising memory means, computation means and display means, comprising in its memory means a three-dimensional digital model of the workpiece, and able to record the coordinates of the points acquired by the sensor the method comprising the steps consisting of:segmenting (1010) of the CAD model into a set of surfaces, designated as nodes, each node corresponding to a surface that is visible in a single acquisition according to the characteristics of the sensordetermining (1020) the visibility of each node from each position of the sensor relative to said nodedetermining common visibilities (1030) between the nodes.