Laser Tracker Contour Measurement for Rotating Bodies

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Solution Overview

Problem

Existing methods for measuring the contour of bodies and checking their positioning about an axis of rotation are labor-intensive and lack precision, particularly when dealing with rotationally symmetrical or out-of-round objects like rollers, and conventional mechanical measuring devices are cumbersome and prone to wear.

Innovation Solution

A method using a laser tracker system with a measuring ball and cantilever arm that follows the peripheral surface of the body as it rotates, ensuring precise contact and eliminating the need for manual handling, combined with automatic adjustment and measurement protocols for efficient data collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a laser tracker system with manual measuring sphere repositioning is used, then measurement capability is achieved, but measurement time and operator effort increase significantly

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

Solution Approach 1:

The measuring sphere is equipped with a drive mechanism that enables it to move autonomously along the body's surface without manual intervention. The sphere self-adjusts its position by rotating on its own axis and translating along the surface, eliminating the need for operators to manually reposition it between measurements.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The measuring sphere transitions from a static object requiring manual repositioning to a dynamic system with independent motion capabilities. The sphere can rotate and translate automatically, adapting its position in real-time to follow the body's contour during rotation, thereby reducing measurement time while maintaining precision.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If mechanical measuring instruments like templates and rulers are used, then measurement capability is achieved, but device weight and handling difficulty increase

Engineering Contradiction:
Improvemeasurement precisionVSAvoidease of operation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces heavy mechanical measuring instruments (templates, rulers) with a laser-based optical measurement system. The laser tracker emits light beams that are reflected by the measuring sphere back to the detector, eliminating the need for physical contact with heavy mechanical tools while maintaining or improving measurement precision.

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

Solution Approach 2:

The measurement approach changes from direct physical contact with heavy mechanical instruments to non-contact optical parameter measurement. The system measures positional parameters using laser light reflection and triangulation, fundamentally changing the measurement paradigm from mechanical to optical.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If mechanical measuring instruments are used, then measurement capability is achieved, but device durability decreases due to wear and tear

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent eliminates mechanical contact between measuring instruments and the workpiece by using a laser-based optical system. The laser tracker measures positions non-contactfully through light reflection, removing wear and tear issues associated with mechanical templates, rulers, and other contact-based measuring tools.

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

4Extent of automation

If automated laser crawler is used for fuselage measurement, then measurement automation is achieved, but device complexity and cost increase

Engineering Contradiction:
Improveautomation levelVSAvoiddevice complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent extracts the complex automated carriage mechanism from the measurement system. Instead of using a motorized carriage with wheels and rollers that travels along the fuselage, the invention uses a simple rotating body with a lightweight measuring sphere that follows the surface, eliminating the need for complex support structures and drive mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of moving the measuring device along a stationary body (as in the fuselage measurement system), the patent inverts the approach by rotating the body itself and using a lightweight measuring sphere that passively follows the rotating surface. This simplifies the measurement system while achieving full automation.

Inventive Principle:
Principle #13The other way round (Inversion)

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

This approach enables high-precision measurement of contours and positioning accuracy with reduced operator effort, improved precision, and automated data generation, suitable for both rotationally symmetrical and out-of-round bodies, including rollers in continuous casting plants.

Implementation Method 1

A laser beam emitted by the measuring head is reflected back from the measuring sphere to the measuring head

Methodology Applied
Scientific EffectLaser reflection: Reflection

Data Source

PatentEP3387369B1Method for measuring a contour of a body or for checking the position thereof about an axis of rotation
Publication Date: 2019.10.09 SMS GROUP GMBH
  • EP3387369B1 patent drawingFigure 1
  • EP3387369B1 patent drawingFigure 2
  • EP3387369B1 patent drawingFigure 3

AI summary

The invention relates to a method and a device (10) for measuring the contour of a body (K), using a laser tracker system (1) having a measurement sphere (2), a measurement head (3), and having an evaluation unit (6). In order to measure the size thereof and/or the contour thereof, the body (K) is caused to rotate about at least one axis of rotation, wherein the measurement sphere (2) follows a peripheral surface (12) of the body (K) and a laser beam (L) is reflected from the measurement sphere (2) back to the measurement head (3). On the basis thereof, the contour of the body (K) is then determined by means of the evaluation unit (6).