Active RFID Height Sensor for Pneumatic Chassis

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Solution Overview

Problem

Conventional ride height sensors face challenges in providing stable and precise distance measurements between a vehicle's axle and body due to low signal strength and interference from environmental factors, particularly with ultrasonic and electromagnetic wave technologies.

Innovation Solution

A ride height sensor utilizing a magnetic field scanning device with a simple spacing configuration, offering an improved signal-to-noise ratio and accurate distance measurement through radio signal transmission, and optionally combining with ultrasonic signals for enhanced accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ultrasonic waves are used for distance measurement, then distance information can be obtained, but the reflected signal strength is very low and influenced by environmental factors

Engineering Contradiction:
Improvedistance measurementVSAvoidsignal strength
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the ultrasonic mechanical wave system with an electromagnetic field system. Instead of using ultrasonic transducers that emit and receive mechanical waves, the invention uses a magnetic field generating device and a magnetic field scanning device that detect changes in magnetic field strength, eliminating the problems of low signal strength and environmental interference associated with ultrasonic waves.

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

2Measurement precision

If electromagnetic waves are used for distance measurement, then distance information can be obtained, but the signal strength is very dependent on environmental conditions such as humidity and temperature

Engineering Contradiction:
Improvedistance measurementVSAvoidenvironmental interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces propagating electromagnetic waves with a stationary magnetic field system. The magnetic field generating device creates a stationary magnetic field, and the magnetic field scanning device detects changes in magnetic field strength caused by the position of a ferromagnetic object, eliminating the environmental interference problems associated with propagating electromagnetic waves.

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

3Measurement precision

If a passive transponder is used in a magnetic field system, then distance information can be obtained, but the response signals are extremely small in the microvolt range requiring very complex circuitry

Engineering Contradiction:
Improvedistance measurementVSAvoidcircuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent eliminates the need for complex passive transponder circuitry by using a ferromagnetic object that passively interacts with the stationary magnetic field. The ferromagnetic object itself serves as the sensing element, with its position automatically modulating the magnetic field strength detected by the scanning device, requiring no active electronics or complex signal processing.

Inventive Principle:
Principle #25Self-service

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 provides stable, precise, and reliable distance measurements with improved accuracy and operational reliability compared to conventional sensors, reducing interference and enhancing adaptability to various conditions.

Implementation Method 1

an evaluation unit builds up a stationary magnetic field, which supplies operating energy to a passive transponder

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

a magnetic field scanning device with a simple spacing configuration, offering an improved signal-to-noise ratio and accurate distance measurement

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 3

changes in the magnetic field strength caused by the position of a ferromagnetic object

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentEP2846128B1Active RFID height sensor for pneumaticaly suspended chassis systems
Publication Date: 2016.03.09 BREHMER
  • EP2846128B1 patent drawingFigure 1
  • EP2846128B1 patent drawingFigure 2
  • EP2846128B1 patent drawingFigure 3

AI summary

The invention relates to a ride height sensor (1) for detecting a distance in the area between an axle and a vehicle body, comprising a base station (10) which has an electrically powered electrical circuit arrangement with at least one control unit, a magnetic field generation unit and a receiver unit for receiving radio signals; furthermore, a target station (30) which can be placed at a distance from the base station, comprising an electrically powered circuit arrangement which has a control unit, a magnetic field scanning unit for detecting the magnetic field generated by the magnetic field generation unit of the base station, and a transmitter unit for transmitting radio signals carrying information about the detected magnetic field to the base station.