Sensor-to-Workpiece Calibration for Hard-to-Measure Machined Features

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Solution Overview

Problem

Existing methods require direct measurement of workpieces with dedicated tools, which is time-consuming and difficult for inaccessible features, especially with long tools, and do not efficiently utilize sensor data from intelligent tools for inference.

Innovation Solution

A method to infer workpiece measurement data from sensor data using sensor-to-workpiece data calibration information, derived from sensor data during machining, allowing inference of workpiece features that are hard to measure directly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a measurement device is used to measure workpiece information, then measurement capability is provided, but the device requires frequent calibration which consumes time and resources

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent creates virtual copies of calibration objects using image processing technology. Instead of using physical calibration objects that require manual handling and setup, the system captures images of real calibration objects and generates virtual calibration objects from these images. These virtual copies can be repeatedly used for calibration without physical wear or setup time, significantly reducing calibration time while maintaining measurement precision.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical calibration process with an optical and computational approach. Instead of physically positioning and measuring calibration objects using mechanical measurement devices, the system uses image capture devices to obtain images, processes these images computationally to generate virtual calibration objects, and uses these virtual objects for calibration. This substitution eliminates mechanical wear and reduces calibration time while maintaining calibration accuracy.

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

2Measurement precision

If calibration is performed frequently to maintain measurement accuracy, then measurement precision is improved, but productivity decreases due to time loss

Engineering Contradiction:
Improvecalibration accuracyVSAvoidmeasurement productivity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

By creating virtual calibration objects from images, the system enables rapid, repeated calibration operations. The virtual calibration objects can be instantly generated and used multiple times without the time-consuming setup and physical handling required for traditional calibration objects. This maintains calibration accuracy while minimizing productivity loss.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system performs preliminary actions by capturing images of calibration objects and generating virtual calibration objects in advance. These virtual calibration objects are stored and can be quickly loaded for calibration operations, eliminating the need for repeated physical setup and preparation during actual measurement operations, thus maintaining both accuracy and productivity.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If physical calibration objects are used for calibration, then calibration accuracy is achieved, but the process requires manual operation and consumes resources

Engineering Contradiction:
Improvecalibration accuracyVSAvoidmanual operation requirement
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent creates virtual calibration objects that are digital copies of physical calibration objects. These virtual objects contain all the necessary calibration information extracted from images of the physical objects. Using virtual calibration objects eliminates the need for manual handling, positioning, and setup of physical calibration objects, significantly improving ease of operation while maintaining calibration accuracy through the preserved geometric and measurement properties of the original objects.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system enables self-service calibration by automatically capturing images of calibration objects, processing these images to extract calibration information, and generating virtual calibration objects without requiring manual intervention. The automated image processing and virtual object generation eliminate the need for operators to manually set up and manage physical calibration objects, reducing operational complexity while maintaining calibration accuracy.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3948453B1Calibration method and method of obtaining workpiece information
Publication Date: 2026.04.29 RENISHAW PLC
  • EP3948453B1 patent drawingFigure 1
  • EP3948453B1 patent drawingFigure 2
  • EP3948453B1 patent drawingFigure 3

AI summary

A method comprising: a) causing a tool mounted on a machine tool to work on a workpiece, and at least one sensor, which is configured to measure one or more aspects of the tool and/or machine tool, collecting sensor data during said working; b) a measurement device inspecting the part of the workpiece that was worked on at step a) to obtain measurement data; and c) calculating sensor-to-workpiece data calibration information from the sensor data and the measurement data.