Shape Measurement Timing Estimation for Accurate Probe Positioning

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Solution Overview

Problem

Non-contact shape measuring devices face accuracy issues due to temporal errors and variations in synchronizing image acquisition and coordinate data from separate devices, leading to inaccuracies in processing object shape calculations.

Innovation Solution

A processing system that includes a measuring unit, a control unit for generating positional information and a generation period signal, an acquisition unit for acquiring these signals, an estimation unit for calculating the generation period based on statistical values, and a shape calculation unit that uses this information to accurately determine the processing object's shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If image acquisition and coordinate data are obtained from separate devices independently, then device complexity is reduced and ease of operation is improved, but temporal errors occur between acquisitions leading to deterioration in measurement precision

Engineering Contradiction:
Improveindependent operation of measuring probe and NC machine toolVSAvoidaccuracy of shape data
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system uses feedback by measuring the actual acquisition intervals of generation period signals, calculating statistical values, and using this information to estimate the true generation timing. This closed-loop approach compensates for temporal errors while maintaining independent operation of the measuring probe and NC machine tool.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces strict mechanical/synchronized timing control with a statistical estimation system. Instead of forcing synchronous acquisition through complex coordination mechanisms, the system uses software-based statistical analysis of acquisition intervals to estimate and compensate for temporal errors, substituting mechanical synchronization with computational correction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If synchronous acquisition of image and coordinate data is enforced, then measurement precision is improved, but device complexity increases due to coordination requirements

Engineering Contradiction:
Improveaccuracy of shape dataVSAvoidcoordination between measuring probe and NC machine tool
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary estimation process that mediates between the independently operating measuring probe and NC machine tool. By measuring acquisition intervals and estimating generation timing through statistical analysis, the system creates a virtual synchronization mechanism that avoids direct coordination complexity while maintaining measurement accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If temporal error compensation is implemented through complex synchronization mechanisms, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improveaccuracy of shape dataVSAvoidindependent control of measuring devices
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system implements self-service by having the measuring probe and NC machine tool continue to operate independently while the estimation unit automatically measures acquisition intervals, calculates statistical values, and compensates for temporal errors without requiring operator intervention or coordination. The system corrects its own timing errors autonomously.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3733345B1Processing system, measurement probe, shape measuring device, and program
Publication Date: 2024.01.17 NIKON CORP
  • EP3733345B1 patent drawingFigure 1
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  • EP3733345B1 patent drawingFigure 3

AI summary

A processing system includes a control unit that generates positional information related to a position of a measuring unit at a time of measuring a processing object and outputs the generated positional information and a generation period signal indicating a period during which the positional information is generated, an acquisition unit that acquires the positional information and the generation period signal which have been output, an acquisition interval calculation unit that calculates a statistical value indicating an interval between acquisition periods regarding a plurality of generation period signals acquired by the acquisition unit, an estimation unit that estimates the period during which the positional information is generated on the basis of the statistical value calculated by the acquisition interval calculation unit, and a shape calculation unit that calculates a shape of the processing object on the basis of measurement information, the positional information, and the period estimated by the estimation unit.