Magnet Orientation Sensing with Gradient Ratios Under Field Disturbance
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Solution Overview
Problem
Existing magnetic position sensor systems face challenges in accurately determining the orientation of a magnet with two degrees of freedom, particularly in the presence of temperature variations, mounting tolerances, demagnetization, and external disturbance fields, while maintaining simplicity and cost-effectiveness.
Innovation Solution
A sensor device and method utilizing a silicon substrate with magnetic sensors to determine the orientation of a pivotable cylindrical magnet by calculating magnetic field gradients and using correction values such as sums of squares and second-order gradients to reduce sensitivity to environmental factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic position sensor systems are used to determine orientation of a magnet with two degrees of freedom, then measurement capability is improved, but sensitivity to temperature variations, mounting tolerances, demagnetization, and external disturbance fields increases
Solution Approach 1:
The patent applies parameter changes by utilizing multiple magnetic field components (Bx, By, Bz) and calculating ratios of these components to determine orientation angles. This approach transforms the measurement parameters from direct field strength measurements to ratio-based calculations, which inherently compensates for variations in temperature, demagnetization, and external fields, thereby maintaining measurement precision while reducing sensitivity to harmful factors
Solution Approach 2:
The patent implements feedback through the use of correction values that are calculated based on measured magnetic field components and used to adjust the orientation determination. The system continuously monitors magnetic field variations and applies corrective calculations to compensate for environmental factors, creating a feedback loop that maintains accuracy despite temperature variations, mounting tolerances, and external disturbance fields
2Reliability
If complex correction algorithms are used to reduce sensitivity to environmental factors, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical or hardware-based compensation mechanisms with software-based calculation algorithms. Instead of using additional physical sensors or complex mechanical adjustment systems to compensate for environmental factors, the invention uses mathematical processing of magnetic field component ratios, thereby achieving high reliability through computational methods rather than increased hardware complexity
Solution Approach 2:
The patent achieves multi-functionality by using the same magnetic field measurements for multiple purposes: determining both the azimuth angle and the polar angle, while simultaneously compensating for temperature variations, mounting tolerances, demagnetization, and external fields. This universal approach allows a single measurement system to perform multiple correction functions without requiring separate dedicated systems for each compensation task
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 highly accurate orientation determination of a magnet with reduced sensitivity to temperature variations, demagnetization, mounting tolerances, and external disturbance fields, enhancing the reliability and precision of magnetic position sensing.
Implementation Method 1
a silicon substrate comprising a plurality of magnetic sensors; a processing circuit configured for: a) determining a first magnetic field gradient (e.g. dBx/dx; dBz/dx) of a first magnetic field component (e.g. Bx; Bz)
Data Source
Figure 1~2
Figure 3A~3B
Figure 4(a)~4(d)
AI summary
A method (1900) of determining an orientation (α, β) of a magnet which is pivotable about a reference position having a predefined position relative to a silicon substrate, comprising: providing a silicon substrate; determining a first/second magnetic field gradient along a first/second direction; determining a first/second angle (α, β) based on said first/second magnetic field gradient and a first/second correction value (D1 to D8). A sensor device configured for performing this method. A sensor system comprising such sensor device and a magnet, optionally connected to a joystick.