2D Laser Displacement Meter for 3D Surface Roughness
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Solution Overview
Problem
Conventional methods for evaluating three-dimensional surface roughness of untransportable objects, such as ship hulls, are labor-intensive and unsuitable for measuring large areas due to size and weight limitations of traversing devices, and struggle with accurately measuring shape parameters on smooth surfaces.
Innovation Solution
A three-dimensional surface roughness evaluating device using a two-dimensional laser displacement meter with a movement mechanism and calculating device to generate surface roughness data by averaging displacement data in the Y-axis direction and subtracting reference surface data from X-Y plane coordinates, allowing for efficient measurement of wide areas with reduced device size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional point-like laser displacement meter mounted on an X-Y stage is used to measure surface roughness, then measurement precision is improved, but device size and weight increase, making on-site handling difficult
Solution Approach 1:
The patent replaces the mechanical X-Y stage traversal system with a two-dimensional laser displacement meter that directly scans the surface. The 2D laser displacement meter eliminates the need for mechanical positioning stages, significantly reducing device weight and complexity while maintaining measurement precision through optical scanning capabilities.
Solution Approach 2:
The two-dimensional laser displacement meter integrates both X and Y axis measurement capabilities into a single device, eliminating the need for separate mechanical stages for each axis. This multi-functional approach allows the device to cover large measurement areas without requiring additional mechanical components, reducing overall weight and improving portability.
2Measurement precision
If an X-Y stage with precision motors is used to traverse the laser displacement meter, then measurement precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent eliminates mechanical positioning systems (X-Y stages with motors) and replaces them with a two-dimensional laser displacement meter that performs optical scanning. This substitution removes complex mechanical components, motors, and controllers, significantly reducing device complexity while maintaining positioning precision through optical methods.
3Measurement precision
If a roughness replica method is used to measure ship hull surface roughness, then measurement accuracy is improved, but labor requirements and measurement time increase significantly
Solution Approach 1:
The patent uses a two-dimensional laser displacement meter to directly capture optical copies of the surface topography without creating physical replicas. This digital copying method eliminates the labor-intensive processes of applying thermoplastic resin, creating physical replicas, and manually scanning them in laboratories, while maintaining measurement accuracy through direct optical measurement.
Solution Approach 2:
The patent replaces the manual replica creation and scanning process with automated optical scanning using a two-dimensional laser displacement meter. This substitution eliminates manual labor for replica preparation and enables rapid digital measurement, significantly improving productivity while maintaining measurement precision.
4Productivity
If a shaded image recording device is used to measure surface roughness, then measurement speed is improved, but accuracy of shape parameter measurement on smooth surfaces deteriorates
Solution Approach 1:
The patent replaces the shaded image recording method with a two-dimensional laser displacement meter that directly measures surface topography through optical time-of-flight or phase-shift methods. This substitution enables accurate measurement of shape parameters on smooth surfaces by directly detecting surface height variations rather than relying on light shadow patterns, maintaining both speed and precision.
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
Enables quick, successive, and direct acquisition of surface roughness parameters over large areas, improving measurement efficiency and accuracy without the need for large, heavy traversing devices, and is suitable for untransportable objects like ship hulls.
Implementation Method 1
a two-dimensional laser displacement meter (12)
Implementation Method 2
measuring a displacement in an X-axis direction at fixed intervals by use of a two-dimensional laser displacement meter
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
A three-dimensional surface roughness evaluating device includes: a two-dimensional laser displacement meter; a movement mechanism which moves the two-dimensional laser displacement meter in an X-axis direction; a movement distance measuring device which measures a movement distance of the two-dimensional laser displacement meter in the X-axis direction; and a calculating device which generates three-dimensional surface roughness data of a measurement target on the basis of displacement data acquired by the two-dimensional laser displacement meter and movement distance data acquired by the movement distance measuring device, wherein the two-dimensional laser displacement meter is disposed so that the width direction of the two-dimensional laser displacement meter coincides with a Y-axis direction, to be able to measure displacement data of coordinates in the Y-axis direction at fixed intervals, the measuring width of the two-dimensional laser displacement meter is at least two or more times mean width of the roughness profile elements RSm of elements of the measurement target, and the calculating device is configured to generate reference surface data of each coordinate by averaging in the Y-axis direction the displacement data acquired at fixed intervals in the X-axis direction by the two-dimensional laser displacement meter, and generate three-dimensional surface roughness data of the measurement target by subtracting the reference surface data of each coordinate from the displacement data of each X-Y plane coordinate.