Angle Sensor Disturbance Field Suppression
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Solution Overview
Problem
Magnetic angle sensors face accuracy issues due to the influence of disturbance magnetic fields, which can cause deviations in measured angles, especially when sensing elements operate in saturated modes and are not optimally positioned relative to the rotating magnetic field.
Innovation Solution
The use of two sensing elements, arranged at different distances from the magnet and operating in non-saturated modes, allows for the suppression of disturbance magnetic field influence by calculating differences in output signals to determine the angle of rotation, thereby improving accuracy and reducing manufacturing and assembly complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sensing elements operate in saturated mode, then the sensor can handle strong magnetic fields, but the measurement accuracy deteriorates due to inability to detect disturbance field strengths
Solution Approach 1:
The patent changes the operating mode parameter of the sensing elements from saturated mode to non-saturated mode. This allows the sensing elements to linearly respond to magnetic field strength variations, enabling detection of disturbance field strengths and improvement of angle measurement accuracy while maintaining the ability to handle strong magnetic fields.
Solution Approach 2:
The patent introduces a feedback mechanism where the processor uses the output signals from multiple sensing elements to determine both the angle of rotation and the strength of the magnetic field. This feedback allows the system to compensate for disturbance fields and maintain measurement accuracy even in strong magnetic field environments.
2Illumination intensity
If sensing elements are positioned close to the magnet for better signal strength, then the signal-to-noise ratio improves, but the sensor becomes more sensitive to disturbance magnetic fields
Solution Approach 1:
The patent divides the sensing function into multiple sensing elements positioned at different distances from the magnet. This segmentation allows the system to simultaneously capture signal strength information (from close positioning elements) and disturbance field information (from distant positioning elements), enabling compensation for harmful disturbance fields.
Solution Approach 2:
The patent introduces intermediate sensing elements positioned at intermediate distances from the magnet. These intermediary sensing elements act as mediators that detect both the primary magnetic field signal and the disturbance field, allowing the processor to separate and compensate for the harmful disturbance component while maintaining strong signal detection.
3Measurement precision
If multiple sensing elements are used to suppress disturbance fields, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent merges multiple sensing elements into a single integrated sensor package with a unified readout circuit. This combining approach allows the system to achieve high measurement accuracy through multiple sensing elements while minimizing device complexity by sharing common components such as the processor and signal conditioning circuits.
Solution Approach 2:
The patent designs the sensing element package to serve multiple functions: detecting the primary magnetic field signal, detecting disturbance field strength, and providing redundancy for reliability. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall device complexity while maintaining high measurement accuracy.
4Measurement precision
If sensing elements are precisely positioned on the rotation axis for optimal measurement, then measurement accuracy improves, but manufacturing and assembly difficulty increases
Solution Approach 1:
The patent applies local quality by positioning sensing elements at different radial distances from the rotation axis rather than requiring precise axial positioning. This allows each sensing element to be optimally positioned for its specific function (signal detection or disturbance detection) while reducing the overall positioning precision requirements for manufacturing and assembly.
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 enhances the accuracy of angular measurements by canceling the effect of disturbance magnetic fields, providing redundancy and reliability, and reducing costs associated with complex positioning requirements.
Implementation Method 1
a first sensing element to provide a first set of output signals associated with a magnetic field produced by a rotatable magnet, wherein amplitudes of the first set of output signals may be dependent on a strength of the magnetic field at the first sensing element
Data Source
AI summary
An angle sensor may include a first sensing element to provide a first set of output signals associated with a magnetic field produced by a rotatable magnet. The first sensing element may be arranged at a first distance from a surface of the rotatable magnet along a given direction, and may be configured to operate in a non-saturated mode. The angle sensor may include a second sensing element to provide a second set of output signals associated with the magnetic field produced by the rotatable magnet. The second sensing element may be arranged at a second distance from the surface of the rotatable magnet along the given direction, and may be configured to operate in a non-saturated mode.