Mechatronic Self-Verification Using Multilateration Point Clouds

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Solution Overview

Problem

Current multilateration methods for measuring the volumetric positioning of mechatronic systems are time-consuming and require manual intervention, as they necessitate moving the measuring device multiple times to each position, leading to increased measurement uncertainty due to thermal drift and higher costs.

Innovation Solution

An integrated multilateration approach where a measuring device attached to the mechatronic system's end effector moves sequentially to a volumetric point cloud, taking distance measurements from fixed fiducial points, allowing for automatic data acquisition and reducing the need for multiple device repositionings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional multilateration methods are used with multiple measuring devices, then measurement accuracy is improved, but measurement time and device complexity increase significantly

Engineering Contradiction:
Improvevolumetric positioning accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

Instead of moving the measuring device to multiple positions (traditional approach), the invention inverts the approach by attaching the measuring device to the moving component (end effector) and keeping fiducial points fixed in space. This allows the system to self-verify its own positioning accuracy throughout the volumetric workspace, dramatically reducing measurement time while maintaining accuracy.

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

Solution Approach 2:

The mechatronic system performs self-verification by attaching the measuring device to its own end effector. The system uses its own movements to trigger measurements at different positions, eliminating the need for external operators to manually reposition measuring devices multiple times, thus reducing both time and operational complexity.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If manual repositioning of measuring device is performed multiple times, then complete volumetric coverage is achieved, but thermal drift effects increase measurement uncertainty

Engineering Contradiction:
Improvevolumetric positioning accuracyVSAvoidmeasurement uncertainty
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The measuring device remains continuously attached to the end effector throughout the entire measurement process, enabling continuous data acquisition as the end effector moves through the volumetric workspace. This eliminates interruptions and repositioning events that would cause thermal drift, maintaining measurement reliability and reducing uncertainty.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

By inverting the traditional approach and attaching the measuring device to the moving component rather than keeping it stationary, the system achieves continuous measurement coverage without repeated mounting/demounting cycles, thereby eliminating the thermal drift effects that arise from manual repositioning.

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

3Ease of manufacture

If sequential measurement approach is used with single measuring device, then cost is reduced, but total measurement time increases

Engineering Contradiction:
Improvesystem costVSAvoidmeasurement efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The invention transforms the static measurement approach into a dynamic one by attaching the measuring device to the moving end effector. This allows the single measuring device to automatically traverse the entire volumetric workspace through the end effector's movements, achieving complete coverage efficiently without requiring multiple devices or repeated sequential positioning, thus maintaining low cost while dramatically improving measurement productivity.

Inventive Principle:
Principle #15Dynamics

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 method significantly reduces measurement time and uncertainty by enabling automatic verification, minimizing thermal drift effects, and lowering costs while maintaining accurate 3D position and orientation measurements.

Implementation Method 1

a measuring device... allows the interferometric measurement of the light beam provided by the laser interferometer

Methodology Applied
Scientific EffectOptical measurement:

Implementation Method 2

a laser interferometer, with different optics configurations, allows detecting position, geometrical and form errors

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 3

due to the suitability of the laser wavelength for long length measurements, due to its long-coherence length

Methodology Applied
Scientific EffectCoherence:

Data Source

PatentEP3745223B1Method for self-verification of mechatronic systems
Publication Date: 2023.03.15 FUNDACION TEKNIKER
  • EP3745223B1 patent drawingFigure 1
  • EP3745223B1 patent drawingFigure 2A~2B
  • EP3745223B1 patent drawingFigure 3

AI summary

A method for determining the volumetric error performance of a movable mechatronic system (20, 20') comprising: defining (31) a volumetric point cloud (25) depicting the volumetric work space of the mechatronic system (20, 20'), said volumetric point cloud (25) comprising N points; attaching (32) a measuring device (21) to the mechatronic system (20, 20'); fixing (33) M fiducial points (24) surrounding the mechatronic system (20, 20'), wherein M>3; defining (34) a common reference system for the mechatronic system (20, 20'), the measuring device (21) and the M fiducial points (24); sequentially moving the measuring device (21) to each of the N points of the volumetric point cloud (25) and, from each position in the volumetric point cloud (25), acquiring (35) a distance value (Dij) to each of the M fiducial points (24); processing said N x M distance values Dij applying a multilateration approach (37) for obtaining (38) the actual coordinates of each of the N actual positions to which the measuring device (21) has been moved. Measuring system.