Magnetoelastic Sensor Dual-Channel Torque Measurement
Solution Overview
Problem
Existing magnetoelastic sensor technologies face challenges in accurately measuring stress and torque while simultaneously detecting external magnetic fields, leading to temporary 'blindness' and reduced sensitivity due to complex mathematical equations and the need for multiple magnetic zones, which complicates operations in confined spaces and can result in incorrect readings.
Innovation Solution
A method and device utilizing a two-band configuration with two magnetic zones of opposite orientation, where one channel measures stress in common mode rejection and another channel detects external magnetic fields in common mode acceptance, allowing for simultaneous measurement and differentiation of stress and external magnetic field influences, thereby reducing the need for additional magnetic tracks and enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex mathematical equations and multiple magnetic zones are used to detect external magnetic fields, then measurement accuracy is improved, but device complexity increases and temporary blindness occurs
Solution Approach 1:
The sensor is divided into two independent channels: a first channel configured for common mode rejection to measure stress/torque, and a second channel configured for common mode acceptance to detect external magnetic fields. This segmentation allows each channel to specialize in one function, improving measurement accuracy without requiring complex mathematical equations to process data from multiple magnetic zones.
Solution Approach 2:
The magnetoelastic body with dual-band magnetization serves multiple functions simultaneously: it acts as both the sensing element for stress/torque measurement and the reference for external magnetic field detection. The same physical structure provides information for both measurement channels, eliminating the need for additional complex components.
2Measurement precision
If multiple magnetic zones are used to detect external magnetic fields, then measurement accuracy is improved, but the sensor size increases making it unsuitable for confined spaces
Solution Approach 1:
The first and second channels are merged into a single integrated sensor unit that shares common components including the magnetoelastic body, magnetic zones, and signal processing circuitry. This combining approach enables the sensor to detect both stress/torque and external magnetic fields simultaneously within a compact form factor suitable for confined spaces.
Solution Approach 2:
The dual-band magnetized magnetoelastic body performs multiple functions within a single component: it provides the magnetic signal for stress/torque measurement while simultaneously serving as the reference for external magnetic field detection. This multi-functionality eliminates the need for separate magnetic zones or additional sensing elements that would increase sensor size.
3Measurement precision
If switching between common mode acceptance and differential mode is implemented, then external magnetic field detection is improved, but measurement speed decreases due to temporary blindness
Solution Approach 1:
The second channel is preliminarily configured in common mode acceptance mode to continuously monitor external magnetic fields before they interfere with stress/torque measurements. This preliminary detection allows the system to anticipate and compensate for magnetic field variations in real-time, eliminating the need to switch modes and preventing measurement blindness.
Solution Approach 2:
Both channels operate continuously and simultaneously without interruption or mode switching. The first channel continuously measures stress/torque while the second channel continuously detects external magnetic fields, ensuring uninterrupted measurement capability and eliminating temporary blindness periods associated with mode transitions.
4Measurement precision
If complex mathematical equations are used to compensate external magnetic fields, then measurement accuracy is improved, but processing time increases
Solution Approach 1:
The external magnetic field signal is extracted separately through the second channel configured for common mode acceptance, isolating it from the stress/torque measurement channel. This extraction eliminates the need for complex mathematical compensation equations, as the magnetic field signal is directly measured and can be subtracted or compensated through simple signal processing operations.
Solution Approach 2:
The second channel acts as an intermediary that directly measures external magnetic field effects, providing a clean reference signal that mediates between the physical magnetic field and the stress/torque measurement. This intermediary approach simplifies the compensation process by providing direct measurement data rather than requiring complex mathematical modeling and calculation.
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 approach enables precise, fast, and reliable measurement of stress and torque, even in confined spaces, by correlating external magnetic field effects with stress measurements, improving accuracy and reducing false signal detection, and meets safety integrity level specifications for applications like aerospace and automotive industries.
Implementation Method 1
Magnetoelastic sensors are well known in the state of the art. This non-contact sensor technology utilizes fundamental mechanical and magnetic properties of the material to measure different process parameters. The process involves measuring changes in the properties of remanent magnetic fields as the mechanical characteristics change, such as shear stress, as external forces are applied onto the sensor host.
Data Source
AI summary
A method for measuring stress applied to a magnetoelastic body, simultaneously detecting a potential external magnetic field affecting a magnetoelastic sensor and allocating a non-stress related influence affected by the field on the body, including applying at least two opposite magnetic zones on the body, providing at least one sensor including at least one first (1) and second (2) channel having at least two axially aligned coils each, arranged adjacent to the magnetized zone of the body, both channels having different sensitivity relative to the field, setting-up channel 1 as a common mode rejection channel and channel 2 as a common mode acceptance channel, reading the magnetized zones when stress is applied to the body, measuring the stress by channel 1 leading to an opposite sensitive direction, and detecting the impact of the field to the magnetized zones by channel 2 leading to an identical sensitive direction.