Pivotable Magnet Orientation Sensor Using Magnetic Field Gradients
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Solution Overview
Problem
Existing magnetic position sensor systems face challenges in accurately determining the orientation of a pivotable magnet with two degrees of freedom while being sensitive to temperature variations, mounting tolerances, demagnetization, and external disturbance fields, and often require complex sensor arrangements.
Innovation Solution
A sensor device with a semiconductor substrate and multiple magnetic sensors configured to measure and calculate magnetic field gradients, using a processing circuit to determine angles based on these gradients, reducing sensitivity to environmental factors and simplifying the sensor arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex sensor arrangements are used to determine magnet orientation with two degrees of freedom, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the measurement task into two separate single-degree-of-freedom measurement systems. Each sensor device measures only one rotational angle (α or β) around a single axis, rather than attempting to measure both angles simultaneously with a complex multi-axis sensor array. This segmentation simplifies the sensor arrangement while maintaining the capability to determine full magnet orientation through coordinate transformation of the two angle measurements.
2Measurement precision
If traditional magnetic position sensor systems are used to measure magnet orientation, then measurement capability is achieved, but sensitivity to temperature variations and external disturbance fields increases
Solution Approach 1:
The patent replaces traditional magnetic field-based orientation measurement with a gradient-based measurement approach. Instead of directly measuring magnetic field components that are sensitive to temperature and external fields, the system measures magnetic field gradients which are inherently more stable. The processing circuit then uses these gradient measurements to calculate the magnet orientation angles, substituting a more robust measurement mechanism for the traditional sensitive magnetic sensing approach.
3Measurement precision
If magnetic sensors are used to detect field components in multiple directions, then orientation information is obtained, but manufacturing precision requirements increase due to mounting tolerances
Solution Approach 1:
The patent segments the orientation measurement into two independent single-axis measurements rather than requiring simultaneous multi-directional sensing. Each sensor device is mounted on a single axis to measure one angle, which relaxes the mounting precision requirements compared to aligning multiple sensors in multiple directions. The complete orientation information is reconstructed by combining the measurements from both segmented systems through coordinate transformation.
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 sensor device provides highly accurate orientation determination of a pivotable magnet with reduced sensitivity to temperature variations, mounting tolerances, and external disturbance fields, while requiring a simpler sensor setup.
Implementation Method 1
each of the first and second magnetic sensor (S1, S2) is configured for measuring a first magnetic field component (e.g. Bx1, Bx2) oriented in said first direction (X), and a second magnetic field component (e.g. By1, By2) oriented in a second direction (e.g. Y) parallel to the semiconductor substrate
Data Source
AI summary
A sensor device for determining the orientation of a magnet that is pivotable about a reference point. the sensor device includes a semiconductor substrate including a first and a second magnetic sensor spaced apart in a first direction, each configured for measuring a first magnetic field component oriented in the first direction, and a second magnetic field component oriented in a second direction; wherein the sensor device further includes a processing circuit configured for determining: i) a first magnetic field gradient; ii) a second magnetic field gradient; iii) a first angle based on the first magnetic field gradient; iv) a second angle based on the second magnetic field gradient. A sensor system includes the sensor device and the magnet.