Door Leaf Radar Sensor for Obstruction Detection

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Solution Overview

Problem

Existing door leaf sensor systems struggle to reliably detect both stationary and moving obstructing objects during door movement, often failing to distinguish between approaching and receding objects, which can lead to collisions.

Innovation Solution

A radar-based sensor system mounted on the door leaf that emits and detects radar radiation, generating a Doppler signal, with an evaluation unit that accounts for the sensor's speed to differentiate obstructing objects based on their kinematic behavior, using a background data set to identify deviations in the Doppler spectrum and generate object detection signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a stationary radar unit is used to detect obstructing objects, then the device complexity is reduced, but the ability to detect stationary objects is lost because no Doppler signal is generated

Engineering Contradiction:
Improvedetection reliabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The radar sensor is integrated directly into the door leaf structure, combining the detection function with the door assembly. This merging allows the sensor to move with the door, generating Doppler signals for both stationary and moving objects, thereby resolving the contradiction between detection reliability and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The door leaf itself acts as an intermediary carrier for the radar sensor. By mounting the sensor on the moving door leaf rather than using a stationary mounting, the system generates the necessary Doppler effect for detecting all objects including stationary ones, without requiring a complex separate detection system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the radar sensor is mounted on the door leaf to detect both stationary and moving objects, then the detection capability is improved, but the device complexity increases

Engineering Contradiction:
Improveobject detection reliabilityVSAvoidsensor mounting complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The radar sensor is integrated directly into the door leaf structure, combining the detection function with the door assembly. This merging allows the sensor to move with the door, generating Doppler signals for both stationary and moving objects, thereby resolving the contradiction between detection reliability and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the Doppler signal spectrum is evaluated taking sensor speed into account to distinguish approaching and receding objects, then the measurement precision is improved, but the evaluation complexity increases

Engineering Contradiction:
Improveobject classification precisionVSAvoidsignal evaluation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs a learning step before normal operation to establish a background data set representing the environment without obstructing objects. This preliminary action allows the evaluation unit to compare current Doppler spectra against the stored background, simplifying the detection of approaching objects by focusing only on deviations from the known background pattern.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The evaluation unit continuously compares the current Doppler signal spectrum with the stored background data set and adjusts object detection based on deviations. This feedback mechanism enables precise classification of objects by their motion state while using the background model to simplify the evaluation process.

Inventive Principle:
Principle #23Feedback

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

The system effectively detects stationary and moving obstructing objects, improving collision avoidance by distinguishing between approaching and receding objects, thereby enhancing door movement control and safety.

Implementation Method 1

The radar unit is configured to provide a Doppler signal during operation. An evaluation unit is configured to evaluate the spectrum of the Doppler signal taking the sensor's speed into account

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 2

The sensor comprises a radar unit capable of emitting radar radiation and detecting reflected radiation

Methodology Applied
Scientific EffectRadar: Radar

Data Source

PatentEP4492089A1Systems and methods for the detection of obstructing objects during the movement of a door leaf
Publication Date: 2025.01.15 PEPPERL & FUCHS SE
  • EP4492089A1 patent drawingFigure 1
  • EP4492089A1 patent drawingFigure 2
  • EP4492089A1 patent drawingFigure 3

AI summary

An exemplary embodiment of the invention relates to a system (1) comprising a door leaf (10) and a sensor (20) configured to detect obstructing objects (O4-O7) during the movement of the door leaf (10). The sensor (20) comprises a radar unit (21) capable of emitting radar radiation and detecting reflected radiation (RR), wherein the radar unit (21) is mounted on the door leaf (10) and is moved together with the door leaf (10), the radar unit (21) being configured to provide a Doppler signal (DS) during operation, and an evaluation unit (22) configured to evaluate the spectrum of the Doppler signal (DS) taking the sensor (20)'s speed into account, and to generate an object detection signal (ODS) based on the evaluation result.