Encoder Magnet Sensor Layout for Stray-Field-Resistant Angle Detection
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Solution Overview
Problem
Existing magnetic rotation sensors for encoder magnets are prone to measurement quality reduction and parasitic effects due to stray magnetic fields, particularly in environments with strong electromagnetic interference, and existing compensation methods are complex and space-consuming.
Innovation Solution
A device and method that arranges multiple magnet sensors in specific angular positions within the magnetic field planes of an encoder magnet, reducing the influence of stray fields by configuring them to detect alignment angles that satisfy a specific angular relationship, allowing for reliable encoder magnet rotation angle determination with reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple magnet sensors are arranged in specific angular positions to reduce stray field influence, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The measurement task is segmented into multiple independent sensor measurements taken at different angular positions. Each sensor measures the magnetic field at its specific position, and the final rotation angle is calculated by combining these segmented measurements, thereby improving precision while maintaining manageable complexity
Solution Approach 2:
The solution transitions from a single-point measurement to a multi-dimensional angular arrangement of sensors. By distributing sensors across different angular positions around the encoder magnet, the system captures magnetic field information from multiple spatial dimensions, enabling more accurate rotation angle determination through geometric relationships
2Reliability
If magnet sensors are arranged in multiple plane-parallel magnetic field planes, then reliability is improved, but installation space increases
Solution Approach 1:
The system utilizes the third dimension (axial direction) by arranging sensors in multiple plane-parallel magnetic field planes along the rotation axis. This vertical stacking approach improves reliability through redundant measurements from different planes while minimizing the lateral installation footprint, as sensors are distributed along the axial direction rather than spreading out horizontally
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 configuration effectively minimizes the impact of stray magnetic fields, enabling accurate and efficient encoder magnet rotation angle measurement while optimizing sensor placement for cost-effectiveness and space-saving.
Implementation Method 1
As a single sensor element, a Hall sensor, a TMR sensor, a GMR sensor, an AMR sensor, and/or a fluxgate sensor, for example, is used to detect the alignment angle of the magnetic field
Implementation Method 2
As a single sensor element, a Hall sensor, a TMR sensor, a GMR sensor, an AMR sensor, and/or a fluxgate sensor, for example, is used to detect the alignment angle of the magnetic field
Implementation Method 3
As a single sensor element, a Hall sensor, a TMR sensor, a GMR sensor, an AMR sensor, and/or a fluxgate sensor, for example, is used to detect the alignment angle of the magnetic field
Implementation Method 4
As a single sensor element, a Hall sensor, a TMR sensor, a GMR sensor, an AMR sensor, and/or a fluxgate sensor, for example, is used to detect the alignment angle of the magnetic field
Implementation Method 5
The encoder magnet is rotatably arranged about a rotation axis or is arranged to rotate about a rotation axis to generate a magnetic field. The magnetic field comprises a plurality of plane-parallel magnetic field planes, wherein a surface normal of the plane-parallel magnetic field planes is parallel to the rotation axis of the encoder magnet
Data Source
AI summary
A device for determining an encoder magnet rotation angle is provided, wherein the device includes an encoder magnet and a number of n greater than or equal to two magnet sensors. The magnetic field includes a plurality of plane-parallel magnetic field planes, wherein a surface normal of the plane-parallel magnetic field planes is parallel to an encoder magnet rotation axis. The magnetic field further includes a plurality of magnetic field vectors in the plane-parallel magnetic field planes. The two magnet sensors are in at least one of the plane-parallel magnetic field planes, wherein a first magnetic field vector has a first angle at a position of a first magnet sensor, and wherein a number n−1 of further ones of the magnet sensors are arranged at positions in the magnetic field whose magnetic field vectors have an angle which satisfies the equationθi=θi-1+360°n,wherein 1<i≤n.