Vehicle Capacitive Sensor Filtering for Reliable Activation Detection

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Solution Overview

Problem

Capacitive sensing in vehicles is prone to interference from shifting electric charges and external influences, such as parasitic capacities and electromagnetic compatibility issues, which affect the accuracy of detecting activation actions for activating vehicle functions.

Innovation Solution

An arrangement with a sensor element, a controlling arrangement, and an evaluation filter arrangement that performs band-pass filtering and transconductance conversion to provide a robust sensor signal specific to changes in the surroundings, reducing interference and enhancing detection reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If charge transfer is used to evaluate the sensor element, then capacitive sensing can be achieved, but interfering emissions and electromagnetic compatibility issues occur

Engineering Contradiction:

Improvecapacitive sensing capabilityVSAvoidinterfering emissions

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

An evaluation filter arrangement is introduced as an intermediary component between the sensor element and the evaluation system. This filter arrangement processes the sensor signal to eliminate interfering emissions while preserving the capacitive sensing capability, thus resolving the contradiction between measurement precision and harmful emissions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If capacitive sensing is used to detect activation actions, then function activation can be enabled, but interfering influences from surroundings affect sensing accuracy

Engineering Contradiction:

Improvefunction activation capabilityVSAvoidsensing accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The evaluation filter arrangement serves as a mediator that processes the sensor signal to eliminate interfering influences from the surroundings. This allows capacitive sensing to maintain its ease of operation for function activation while significantly improving sensing accuracy by filtering out parasitic capacities and external electromagnetic interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If band-pass filtering and transconductance conversion are applied, then robustness against interfering influences is improved, but device complexity increases

Engineering Contradiction:

Improverobustness against interferenceVSAvoidevaluation circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The evaluation filter arrangement combines band-pass filtering and transconductance conversion functions into a single integrated circuit block. This merging approach improves robustness against interfering influences while minimizing the increase in device complexity by consolidating multiple functions into one unified evaluation stage.

Inventive Principle:

Principle #5Merging (Combining)

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 solution significantly improves the robustness of capacitive sensing by filtering out interfering influences, allowing for reliable detection of activation actions and accurate activation of vehicle functions, such as unlocking or opening vehicle lids, while maintaining electromagnetic compatibility.

Implementation Method 1

by means of a sensor element, such as a sensor electrode, a variable capacitance can be provided, which is specific for changes in the surroundings of the sensor element

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

an evaluation filter arrangement of the evaluation arrangement for band-pass filtering and/or for transconductance conversion of the sensor signal

Methodology Applied

Scientific EffectBand-pass filtering: Filter (electronic)

Implementation Method 3

an evaluation filter arrangement of the evaluation arrangement for band-pass filtering and/or for transconductance conversion (i.e. in particular conversion of an electric voltage into a corresponding electric current) of the sensor signal

Methodology Applied

Scientific EffectTransconductance conversion:

Data Source

PatentUS12196028B2Arrangement for a vehicle

Publication Date: 2025.01.14 HUF HÜLSBECK & FÜRST GMBH & CO KG

AI summary

An arrangement for a vehicle is provided. The subject arrangement includes:at least one sensor element for sensing a change, in particular an approach by an activation means, in the surroundings of the sensor element,a controlling arrangement which is electrically connected to the sensor element to provide an electric sensor signal specific to a parameter of the sensor element, which in turn is specific to the sensed change in the surroundings,an evaluation arrangement for repeatedly determining the parameter of the sensor element by means of a transmission of the sensor signal to a storage arrangement in order to perform the detection of the activation action, andan evaluation filter arrangement of the evaluation arrangement for bandpass filtering and/or for transconductance conversion of the sensor signal for the transmission to the storage arrangement.