Surface Shape Measurement Apparatus with Dynamic Scanning Path
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Solution Overview
Problem
Accurate surface shape measurement of objects with unknown designed shape data is challenging due to the inability to specify the scanning path of the measurement head, leading to inaccuracies in distance and inclination measurements.
Innovation Solution
A surface shape measurement apparatus and method that includes a support system for distance and angle measurement devices, a driving mechanism for relative movement, and a control system to adjust the scanning path based on reference shape data, with a second calculation part to account for placement errors and refine the shape data for higher precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the scanning path is prespecified based on designed shape data, then the measurement can be performed systematically, but accurate measurement becomes impossible when the designed shape data is unknown
Solution Approach 1:
The invention performs preliminary acquisition of rough shape data before detailed measurement. The measurement head first acquires rough shape data of the measurement object, then uses this rough data to specify the scanning path for subsequent detailed measurement. This preliminary action enables systematic measurement without requiring pre-existing designed shape data.
Solution Approach 2:
The scanning path is not fixed in advance but is dynamically specified based on the acquired rough shape data. The measurement system adapts the scanning path according to the actual object geometry discovered during measurement, making the system versatile for objects with unknown designed shapes while maintaining measurement precision.
2Measurement precision
If the measurement head scans without adapting to the actual surface, then the measurement process is simple, but distance and inclination measurements become inaccurate
Solution Approach 1:
The system performs preliminary acquisition of rough shape data to establish the basis for accurate scanning path specification. This preliminary rough data acquisition enables subsequent precise distance and inclination measurements by providing the necessary geometric reference, justifying the additional measurement step.
Solution Approach 2:
The system uses the acquired rough shape data as feedback to specify and adjust the scanning path for detailed measurement. This feedback mechanism ensures that the measurement head follows an optimal path that adapts to the actual object surface, improving measurement accuracy while managing system complexity through iterative refinement.
3Measurement precision
If placement errors are not corrected, then the measurement process is faster, but the final shape data precision is reduced
Solution Approach 1:
The system calculates placement errors by comparing measured rough shape data with expected geometry, then uses this error information to correct the detailed shape data. This feedback-based error correction process improves final shape data precision by systematically eliminating placement-related inaccuracies.
Solution Approach 2:
Instead of using complex mechanical alignment systems to prevent placement errors, the invention replaces mechanical precision requirements with computational error correction. The system substitutes physical alignment mechanisms with algorithms that calculate and correct placement errors in software, reducing hardware complexity while improving precision.
Data Source
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Figure 3~3(b)
AI summary
For a contactless three-dimensional shape measurement device using probe light, it has been required that first shape data of a measurement object is known in order to preset the locus of operation of a measurement head such that the probe light is incident orthogonally on a measurement surface as possible. A surface shape measurement apparatus to measure a surface shape of a measurement object, including: a distance measurement device which measures a distance to a measurement point on a surface of the measurement object; an angle measurement device which measures inclination of the surface at the measurement point; a first calculation part which calculates reference shape data of the measurement object based on the distance measured by the distance measurement device; and a second calculation part which calculates detailed shape data of the measurement object based on the inclination measured by the angle measurement device and the reference shape data.