Inductive Wheel Position Sensing for Handheld Material Testers

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Solution Overview

Problem

Existing handheld material testing devices face challenges in accurately detecting their path of travel on surfaces, particularly due to issues with direct line of sight requirements and sensitivity to contamination and ambient brightness, which can lead to inaccurate position determination.

Innovation Solution

The device employs inductive signal transmitter and sensor units for inductive coupling, allowing position detection independent of direct line of sight, with magnetic field generation and detection for rotational position sensing, and includes a computing unit for signal comparison and processing to determine the path traveled, incorporating features like sliding bearings for easy assembly and disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If direct line of sight optical detection is used, then position detection can be achieved, but the system becomes sensitive to contamination and ambient brightness

Engineering Contradiction:
Improveposition detection accuracyVSAvoidsensitivity to contamination and ambient brightness
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces optical detection systems with inductive sensing technology. The inductive sensor unit detects changes in the magnetic field generated by the signal transmitter element on the rolling element, enabling position detection without direct line of sight and eliminating sensitivity to optical interference such as contamination and ambient brightness.

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

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the rolling element and the sensor unit. The signal transmitter element generates a magnetic field that penetrates through the chassis, allowing the sensor unit to detect rotational position indirectly through magnetic coupling rather than direct optical contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If inductive coupling is used for position detection, then direct line of sight is not required and sensitivity to contamination is reduced, but the device complexity increases

Engineering Contradiction:
Improveposition detection reliability in various conditionsVSAvoidcomplexity of inductive signal transmission system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The inductive signal transmitter element serves multiple functions: it acts as a marker for position detection, a rotational encoder, and a reference for path calculation. This multi-functionality reduces the need for separate components and simplifies the overall system despite the advanced sensing technology used.

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

3Adaptability or versatility

If rolling elements are used for positioning, then the device can move on surfaces, but accurate path detection becomes difficult on uneven surfaces

Engineering Contradiction:
Improveability to operate on uneven surfacesVSAvoidpath detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The sensor unit continuously monitors the rotational position of the rolling element and provides feedback to calculate the traveled path. This feedback mechanism allows the system to compensate for variations in surface conditions and maintain accurate position detection even when operating on uneven surfaces.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from direct optical measurement in two dimensions to inductive field detection that operates through the chassis structure, adding a third dimension of measurement capability that is insensitive to surface irregularities and enables accurate path detection on uneven surfaces.

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

This design enables reliable and precise position detection on uneven surfaces, insensitive to contamination and ambient brightness, with simplified assembly and improved accuracy through redundant measurement signal analysis and error minimization.

Implementation Method 1

The signal transmitter element is designed as an inductive signal transmitter element and the sensor unit as an inductive sensor unit, which are configured for inductive coupling with each other

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The material testing device preferably comprises a locating sensor unit, in particular an antenna unit, which is designed to transmit and receive electromagnetic waves, especially in the microwave and/or radio wave range, as measurement signals

Methodology Applied
Scientific EffectElectromagnetic wave transmission and backscattering: Reflection

Data Source

PatentEP4172567B1Hand-held material testing apparatus with a position-determining device and method for operating the positon-determining device
Publication Date: 2026.04.08 ROBERT BOSCH GMBH
  • EP4172567B1 patent drawingFigure 1
  • EP4172567B1 patent drawingFigure 2
  • EP4172567B1 patent drawingFigure 3

AI summary

The invention relates to a position-determining device for a hand-held material testing apparatus, which device is designed to detect a distance travelled by the material testing apparatus and comprises at least one signal emitter unit (14) for an arrangement on a rolling element (16) of the material testing apparatus and at least one sensor unit (18), wherein the signal emitter unit (14) comprises at least one signal emitter element (20) sensitive to a change in a measurement signal depending on a rotary position of the rolling element (16), and wherein the sensor unit (20) is provided for an arrangement on a chassis (22) of the material testing device for detecting the measurement signal. According to the invention, the signal emitter element (20) is designed as an inductive signal emitter element and the sensor unit (18) is designed as an inductive sensor unit and these are designed for inductive coupling to one another.