Contactless Axial Force Sensor Using Magnetic Field Asymmetry
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Solution Overview
Problem
Current force measurement technologies face challenges in accurately measuring axial forces on longitudinal objects without physical attachment, especially in dynamic industrial applications, where existing solutions like strain gauge sensors are limited by the need for pre-processing or magnetization, and are not suitable for all environmental conditions.
Innovation Solution
A contactless force measurement sensor using a magnetic principle with a flux concentrator, magnetic field generator, and detector, which generates and detects magnetic fields influenced by applied forces, allowing for measurement without direct attachment and functioning with ferromagnetic materials, even when coated or dusty, and providing high accuracy for axial forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauge sensors are used to measure bending forces, then measurement capability is provided, but physical attachment and pre-processing are required which influence object movement and complicate installation
Solution Approach 1:
The patent replaces mechanical strain gauge attachment with a contactless magnetic field-based measurement system. The sensor uses magnetic field generators and detectors to measure forces on ferromagnetic objects without physical contact, eliminating the need for mounting elements that influence object movement or require complex pre-processing.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary between the sensor and the object being measured. By using magnetic field generators to create fields that interact with ferromagnetic objects and magnetic field detectors to sense these fields, the system enables contactless measurement while maintaining measurement capability.
2Ease of operation
If contactless measurement is implemented, then ease of operation and adaptability are improved, but measurement precision may be reduced
Solution Approach 1:
The patent optimizes measurement precision by carefully controlling magnetic field parameters including frequency, amplitude, and spatial distribution. The system uses alternating magnetic fields at specific frequencies and adjusts field strength parameters to maximize the signal response from ferromagnetic objects while maintaining contactless operation.
Solution Approach 2:
The patent employs dynamic alternating magnetic fields instead of static fields. By using time-varying magnetic fields at optimized frequencies, the system enhances the interaction with ferromagnetic objects and improves signal detection sensitivity, thereby maintaining high measurement precision in contactless mode.
3Measurement precision
If permanent magnetization of the object is required, then measurement can be performed, but the object must be pre-processed which is difficult when the shaft is not accessible or cannot be dismounted
Solution Approach 1:
The patent replaces the requirement for permanent magnetization with an active magnetic field generation system. Instead of relying on pre-magnetized objects, the sensor uses electromagnetic coils to generate alternating magnetic fields that interact with the ferromagnetic object's inherent magnetic properties, eliminating the need for inaccessible pre-processing.
Solution Approach 2:
The patent performs the magnetization function dynamically during measurement operation rather than requiring preliminary permanent magnetization. The magnetic field generators create the necessary magnetic interaction in real-time, allowing measurement on objects that cannot be pre-processed due to accessibility constraints.
4Stability of the object's composition
If the magnetic field detector unit is positioned on the central axis of the flux concentrator, then symmetry is maintained, but sensitivity to axial forces is reduced
Solution Approach 1:
The patent deliberately positions the magnetic field detector unit asymmetrically relative to the flux concentrator, specifically offset from the central axis. This asymmetric positioning creates a non-uniform magnetic field distribution that enhances the detector's sensitivity to axial forces applied to the object, as the offset position experiences greater field variations when forces are applied.
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 precise, non-contact measurement of axial forces on ferromagnetic objects with improved sensitivity and accuracy, suitable for various industrial and environmental conditions, including dynamic applications, without the need for pre-processing or magnetization, and provides a large signal range and good signal-to-noise ratio.
Implementation Method 1
a first magnetic field generating unit being adapted for generating a magnetic field
Implementation Method 2
a first magnetic field detector unit being adapted for detecting a first magnetic field which field being generated by the first magnetic field generating unit and being influenced by the applied force to be measured
Implementation Method 3
wherein the current induced to the first magnetic field detector unit varies dependent on the spread, distracted, and diverged magnetic field lines
Data Source
AI summary
A force measurement sensor for measuring an applied force onto an object is provided. The force measurement sensor includes a sensing unit including a concentrator, a generator, a detector, and an evaluator. The concentrator points towards the object. The generator generates a magnetic field. The detector detects a magnetic field generated by the generator and influenced by the applied force to be measured. The detector outputs a first signal of the detected magnetic field. The evaluator evaluates a signal strength of the signal and determines the applied force based on the signal. A longitudinal axis of the detector is arranged for a lateral offset between the longitudinal axis of the detector and a central axis of the concentrator that is perpendicular to a longitudinal direction of the concentrator.