Floor Slab Radar Sensing for Human Presence Differentiation

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Solution Overview

Problem

Conventional security systems, such as camera-based systems, are inadequate for reliably distinguishing between different types of objects like people and machines, and radar sensors require precise positioning and complex setups for comprehensive monitoring.

Innovation Solution

A system using a radar sensor to detect vibrations of a floor slab caused by movement, analyzing these vibrations to differentiate between humans and technical equipment, with an evaluation unit determining the presence of a person and triggering safety measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If camera-based security systems are used, then the system can monitor the area, but it cannot reliably distinguish between different types of objects like people and machines

Engineering Contradiction:
Improveobject differentiation capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces camera-based optical detection with radar-based electromagnetic wave detection. The radar sensor emits electromagnetic waves and analyzes the reflected signals to detect objects, achieving more reliable differentiation between people and machines through physical property analysis rather than visual recognition, thereby improving reliability while maintaining system simplicity

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

Solution Approach 2:

The patent changes the detection parameter from visual appearance (camera) to physical properties such as radar reflection characteristics, movement patterns, and vibration signatures. By analyzing these physical parameters, the system can reliably distinguish between different object types without requiring complex image processing algorithms

Inventive Principle:
Principle #35Parameter changes

2Reliability

If radar sensors are used for comprehensive monitoring, then reliable object differentiation is achieved, but precise positioning and complex setup are required

Engineering Contradiction:
Improveobject detection accuracyVSAvoidinstallation flexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The radar sensor is designed to perform multiple functions: detecting objects, differentiating between object types, and monitoring safety zones. This multi-functionality eliminates the need for separate sensors for different purposes, allowing comprehensive monitoring with a single device and simplifying installation

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses vibration frequency analysis as a key parameter to differentiate objects. By detecting the natural vibration frequencies of objects when struck by radar waves or during movement, the system can identify object types without requiring precise positioning, as vibration signatures are inherent properties that work across different installation locations

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If a network of radar devices is deployed for comprehensive floor monitoring, then complete coverage is achieved, but the system becomes very complex

Engineering Contradiction:
Improvemonitoring coverage areaVSAvoidnetwork configuration complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges multiple detection functions into a single radar sensor unit. The sensor combines object detection, classification, and safety monitoring capabilities in one device, eliminating the need for complex networks of multiple specialized sensors and simplifying the overall system architecture

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces vibration frequency analysis as an additional dimension of detection. By analyzing the frequency domain characteristics of reflected radar waves, the system achieves comprehensive monitoring through enhanced signal processing rather than through spatial distribution of multiple sensors, reducing the need for extensive sensor networks

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

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

Enables reliable differentiation and flexible, cost-effective monitoring of objects on a floor slab, allowing timely safety responses to potential hazards.

Implementation Method 1

a radar sensor (12) which is designed to detect vibrations of the base plate (50) caused by the movement of an object

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

The strength of the reflection depends on the material properties and the surface of the base plate. The radar sensor is configured to receive the reflected waves. When the base plate vibrates or...As the base plate moves, the distance between the radar sensor and the base plate changes. This change in distance leads to a phase shift and/or a frequency change (Doppler effect) of the reflected waves.

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP4703763A1Safety sensor for monitoring the presence of persons
Publication Date: 2026.03.04 PILZ GMBH & CO KG
  • EP4703763A1 patent drawingFigure 1~3
  • EP4703763A1 patent drawingFigure 4~5
  • EP4703763A1 patent drawingFigure 6

AI summary

A device for monitoring the presence of a person on a floor slab comprises a radar sensor configured to detect vibrations of the floor slab due to movement of an object on the floor slab, in particular due to a person walking on the floor slab, and to generate a corresponding signal, and an evaluation unit configured to determine, based on the signal, whether the object is a person and to provide a control unit with corresponding information in order to ensure the safety of the person.