Cylindrical Hole Target for Accurate 3D Hole Vector Measurement
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Solution Overview
Problem
Existing methods for determining the position and vector of holes in workpieces using structured light scanners are inaccurate due to reliance on single or two-point targets, which can introduce errors, especially when holes are not normal to the surface or are obstructed, and struggle with reflective surfaces and small holes.
Innovation Solution
A scanning system that uses a target with a cylindrical body and shaft, where the target's centerline is collinear with the hole's centerline, allowing for multiple data points to be generated by a scanner to interpolate the longitudinal axis of the cylinder body, thereby determining the hole's position and vector with high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-point target is used to determine hole position, then the device complexity is reduced, but measurement precision deteriorates due to projection errors when the hole is not normal to the local surface
Solution Approach 1:
The patent employs a spherical target geometry instead of a single-point target. The spherical shape provides curved surfaces that reflect structured light in multiple directions, enabling the scanner to capture multiple data points from different angles. This curvature allows accurate determination of the hole position and vector even when the hole is not normal to the local surface, as the spherical surface maintains consistent geometric relationships with the scanner regardless of orientation.
Solution Approach 2:
The invention transitions from a zero-dimensional single-point target to a three-dimensional spherical target. This dimensional expansion allows the target to provide spatial information in multiple dimensions, enabling the system to calculate hole position and vector through multi-point geometry rather than relying on a single point projection. The spherical surface generates data points distributed across three-dimensional space, improving measurement accuracy.
2Measurement precision
If a two-point target is used to generate a centerline, then measurement precision improves, but reliability deteriorates when one of the points becomes blocked or shadowed
Solution Approach 1:
The patent changes the geometric parameters of the target from two discrete points to a continuous spherical surface. This parameter change allows the system to capture numerous data points across the spherical surface rather than relying on just two points. The spherical geometry ensures that even if some points are blocked or shadowed, sufficient unobstructed points remain to accurately determine the hole vector and centerline through geometric fitting.
Solution Approach 2:
The spherical target is designed to preemptively provide multiple potential data points before scanning begins. The spherical geometry ensures that regardless of the scanner's position or orientation, there will always be sufficient unobstructed surface areas to capture the necessary measurement data, eliminating the risk of measurement failure due to point obstruction.
3Device complexity
If a structured light scanner is used without a target to find hole position, then device complexity is reduced, but measurement precision deteriorates due to unknown direction and orientation of the hole
Solution Approach 1:
The patent introduces a spherical target as an intermediary object between the scanner and the hole. This intermediary provides known geometric reference surfaces that the scanner can use to establish coordinate systems and orientation. The spherical target acts as a mediator that translates the unknown hole orientation into measurable geometric relationships, allowing accurate determination of hole position and vector through the target's known spherical geometry.
4Measurement precision
If a target is used with reflective surfaces, then measurement precision improves, but ease of operation deteriorates due to difficulty in capturing enough interior surface data
Solution Approach 1:
The spherical target geometry inherently solves the reflective surface problem by providing continuously curved surfaces that redirect structured light toward the scanner from multiple angles. The curvature ensures that light reflecting off the spherical surface maintains predictable geometric relationships, making it easier to capture sufficient data points even from small holes or difficult-to-reach locations.
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 achieves precise determination of hole positions and vectors, reducing uncertainty and improving accuracy by using a larger scanning area and being usable in any rotational orientation, even with partially obstructed targets.
Implementation Method 1
a structured light scanner to scan the component
Implementation Method 2
determining a position and a vector of a hole formed in a workpiece based on scanned data of the workpiece
Data Source
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AI summary
In examples, systems for determining a position and a vector of a hole formed in a workpiece based on scanned data of the workpiece are described. The system includes a target for coupling to the hole formed in the workpieced, a scanner for projecting a light pattern onto the target and surrounding workpiece and for generating a plurality of data points representative of a surface area of a cylinder body of the target, and a processor for receiving the plurality of data points generated by the scanner and generating a three-dimensional (3D) model of at least a portion of the workpiece. The processor determines a position and a vector of the hole formed in the workpiece for the 3D model based on the plurality of data points representative of the surface area of the cylinder body.