Contactless Distance Sensing With Virtual Beams for Machine Safeguarding

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Solution Overview

Problem

Existing machine safety systems, particularly in human-robot collaboration environments, face challenges in accurately recognizing objects and preventing accidents due to inaccuracies in distance sensor measurements and environmental modeling.

Innovation Solution

A contactless distance sensor system that moves with the machine, using multiple virtual distance measuring beams to compare actual measurement values with predicted values, enhancing object recognition accuracy and robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single virtual distance measuring beam is used for object detection, then the system is simple to implement, but measurement accuracy deteriorates due to deviations in pose and surface model

Engineering Contradiction:
Improveobject recognition accuracyVSAvoidnumber of virtual measuring beams
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The single distance measuring beam is segmented into multiple virtual distance measuring beams (first virtual beam and at least one further virtual beam with offset). Each beam provides an independent measurement path, and the system evaluates whether actual measured values are compatible with virtual measured values from multiple beams simultaneously, thereby improving object detection accuracy while managing system complexity through structured segmentation.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If distance thresholds are adjusted to create a flexible protective dome, then adaptability improves, but reliability deteriorates due to deviations between assumed and actual line of sight

Engineering Contradiction:
Improveprotective dome flexibilityVSAvoiddetection accuracy at edges
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system transitions from a single-line measurement approach to a multi-dimensional evaluation by introducing offset virtual beams that create a volumetric measurement space. Instead of relying on a single distance threshold that may be affected by line-of-sight deviations, the system evaluates compatibility across multiple spatial dimensions (multiple beams with different offsets), thereby maintaining adaptability while significantly improving reliability at edge positions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4414143B1Method and contactless distance sensor for securing a machine
Publication Date: 2025.04.02 SICK AG
  • EP4414143B1 patent drawingFigure 1~2
  • EP4414143B1 patent drawingFigure 3~4
  • EP4414143B1 patent drawingFigure 5~6

AI summary

A method for safeguarding a machine (10) is described, in which objects (18) in a working area (20, 22) of the machine (10) are detected by a moving non-contact distance sensor (12) with at least one distance measuring beam (14) measuring an actual measurement for a distance, generating a first virtual distance measuring beam (28) that simulates the distance measuring beam (14), and comparing the actual measurement with its first virtual measurement. At least one further virtual distance measuring beam (30) is generated with an offset (32) to the first virtual distance measuring beam (28), and a further virtual measurement is calculated. The actual measurement is then compared with the virtual measurements to determine if they are compatible.