Magnetic Position Sensor With Varying Pole Spacing
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Solution Overview
Problem
Magnetic position sensor systems face challenges in achieving a balance between large measurement range and high accuracy, often requiring trade-offs that compromise either range or precision, and existing solutions are complex, requiring advanced processing and more resources than necessary.
Innovation Solution
A position sensor system utilizing a magnetic structure with varying pole distances and a sensor device measuring both in-plane and out-of-plane magnetic field components to generate coarse and fine signals, allowing for accurate position determination using simple arithmetic operations without the need for advanced processors or complex signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic position sensor system uses a constant pole distance structure, then the device complexity is low, but the measurement precision decreases over large ranges
Solution Approach 1:
The magnetic structure employs varying pole distances along the measurement range, creating different local magnetic field characteristics. Each region has optimized pole spacing tailored to its position, enabling high measurement precision across the entire range without requiring complex processing algorithms.
Solution Approach 2:
The pole distance parameter is deliberately varied along the movement direction to encode position information. By changing the spatial parameter (pole distance) rather than relying on complex signal processing, the system achieves high accuracy over large ranges with simple arithmetic operations.
2Measurement precision
If advanced signal processing algorithms are used, then the position measurement accuracy improves, but the computational requirements and device complexity increase
Solution Approach 1:
The patent replaces complex computational signal processing with a physically encoded magnetic field structure. Instead of using algorithms that require significant computational energy, the varying pole distances create distinct magnetic field patterns that can be decoded using simple arithmetic operations, dramatically reducing energy consumption while maintaining high accuracy.
3Measurement precision
If more sensor elements are used, then the measurement accuracy improves, but the device complexity and cost increase
Solution Approach 1:
Rather than increasing the number of sensor elements, the patent changes the spatial parameter of the magnetic structure (pole distances). This approach achieves enhanced measurement accuracy through field differentiation while keeping the sensor device simple and cost-effective.
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 system achieves high accuracy over a large range with reduced computational requirements, enabling precise position detection without the need for sophisticated processing, and is robust against external disturbances.
Implementation Method 1
a first magnetic field component oriented in a first direction substantially parallel to said movement direction or tangential to said movement trajectory, and a second magnetic field component oriented in a second direction substantially perpendicular to the first direction
Data Source
Figure 1(a)~1(c)
Figure 2(a)~2(b)
Figure 3(a)~3(d)
AI summary
A position sensor system (100) for determining a position (X, α) of a sensor device relative to a magnetic structure, the system comprising: said magnetic structure (101) comprising a plurality of poles; said sensor device comprising a plurality of magnetic sensors; the magnetic structure being movable (X, α) relative to the sensor device, or vice versa; wherein: a distance between centres of adjacent poles varies along the movement direction; the sensor device is adapted: for determining a first magnetic field component parallel to, and a second magnetic field component perpendicular to a movement direction, and for calculating a fine signal (Sf) based on a ratio of the first and second magnetic field component; and for determining a coarse signal based on components and/or gradients; and for determining said position based on the coarse signal (Sc) and the fine signal (Sf).