Contactless Distance Sensing With Virtual Beams for Machine Safeguarding

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Solution Overview

Problem

Existing safety systems for machines, particularly robots, struggle with inaccurate object recognition due to discrepancies between predicted and actual environments, leading to false positive detections and productivity losses.

Innovation Solution

A method using contactless distance sensors that simulate multiple virtual distance measurement beams to compare actual measurements with predicted values, enhancing object recognition by incorporating additional virtual beams to account for pose and surface model inaccuracies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single distance measurement beam is used for object recognition, then the device complexity is low, but the measurement precision and object recognition robustness deteriorate due to pose and surface model inaccuracies

Engineering Contradiction:

Improveobject recognition accuracyVSAvoidnumber of distance measurement beams

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The single distance measurement beam is segmented into multiple virtual distance measurement beams (first virtual beam, second virtual beam, third virtual beam) that diverge from different positions. This segmentation allows the system to account for pose inaccuracies and surface model variations by comparing measurements from multiple virtual beam positions, thereby improving object recognition accuracy without requiring additional physical sensors.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Virtual copies of the distance measurement beam are created at different positions and orientations based on the robot's pose and surface model. These virtual beams are calculated positions where the beam would intersect the surface if the robot were at those specific poses. By comparing actual measurements with predictions from multiple virtual beam copies, the system robustly handles uncertainties in pose and surface modeling.

Inventive Principle:

Principle #26Copying

2Area of stationary object

If distance thresholds are adapted to maximize coverage distance, then the area of detection is improved, but the measurement precision deteriorates at edges due to differences between assumed and actual sight beam extent

Engineering Contradiction:

Improvedetection coverage areaVSAvoiddistance measurement accuracy at edges

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The problem is solved by adding a spatial dimension to the measurement evaluation. Instead of using a single distance threshold, the system calculates multiple virtual beam positions that span a range of possible actual beam extents. This creates a three-dimensional evaluation space (position, distance, virtual beam index) that allows the system to maintain large detection coverage while achieving precise edge measurement through multi-point validation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Productivity

If the robot moves closer to the work surface for dynamic operations, then the productivity is improved, but the reliability of safety monitoring deteriorates due to false positive object recognitions from model predictions

Engineering Contradiction:

Improveoperation speed and proximityVSAvoidfalse positive rate in object recognition

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary calculations of multiple virtual beam positions and expected surface intersection points before actual measurement. By pre-computing where the beam should intersect the surface for various robot poses and comparing these predictions with actual measurements, the system establishes a baseline for normal operation. This preliminary action enables the system to distinguish between expected variations (false positives) and actual intrusions (true positives), maintaining high reliability during high-speed operations.

Inventive Principle:

Principle #10Preliminary action

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

Enhances object recognition robustness, reducing false positives and enabling safer, more dynamic machine operations by accurately distinguishing between expected and unexpected objects.

Implementation Method 1

a contactless distance sensor (12) which is moved along with the machine (10) and determines an actual measured value for a distance

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Implementation Method 2

contactless distance sensor for safeguarding a machine... determines an actual measured value for a distance with at least one distance measurement beam

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS12570013B2Method and contactless distance sensor for safeguarding a machine

Publication Date: 2026.03.10 SICK AG

AI summary

A method of safeguarding a machine is provided in which objects are recognized in a work zone of the machine in which a contactless distance sensor that is moved along measures an actual measured value for a distance with at least one distance measurement beam, a first virtual distance measurement beam that simulates the distance measurement beam is formed, and the actual measured value is compared with its first virtual measured value. In this respect, at least one further virtual distance measurement beam having an offset from the first virtual distance measurement beam is formed and a further virtual measured value is calculated with it and a comparison is made whether the actual measured value is compatible with the virtual measured values.