Differential Magnetic Field Sensors for Angular Position Accuracy
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Solution Overview
Problem
Existing measurement devices for determining angular position are prone to positioning errors and interference from non-homogeneous magnetic fields, which affect the accuracy of angular position measurement.
Innovation Solution
A measurement device comprising a rotatable magnet device with perpendicular north and south pole faces and a stationary sensor device with differential magnetic field sensors, positioned between the pole faces to create a homogeneous magnetic field region, reducing interference and enhancing accuracy by differential operation of the sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic sensors are used without differential operation, then the device structure is simple, but positioning errors and interference from non-homogeneous magnetic fields significantly affect measurement accuracy
Solution Approach 1:
The sensor device is divided into multiple magnetic field sensors (first magnetic field sensor and second magnetic field sensor) arranged at different positions. Each sensor measures the magnetic field independently, and the differential operation between these segmented sensors eliminates positioning errors and interference from non-homogeneous magnetic fields, significantly improving angular position measurement accuracy
Solution Approach 2:
The patent applies different functional qualities to different parts of the sensor device. The first and second magnetic field sensors are positioned at specific locations to detect local magnetic field variations. By comparing the differential signals from these locally positioned sensors, the system achieves high measurement precision while compensating for field inhomogeneities
2Measurement precision
If magnetic field sensors are positioned close to the magnet device, then the magnetic field signal is strong, but positioning errors have a greater impact on measurement accuracy
Solution Approach 1:
The patent converts the harmful effect of positioning errors into a beneficial differential signal. By arranging multiple sensors at different positions and performing differential operation on their outputs, the positioning errors that would individually degrade accuracy instead create a measurable differential pattern that, when properly processed, eliminates the error impact and enhances measurement precision
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 a measurement device that is insensitive to positioning errors and reduces interfering magnetic fields, achieving accurate angular position determination with improved resolution and reliability.
Implementation Method 1
The magnet device has a first north pole face of a first magnetic north pole and a first south pole face of a first magnetic south pole... A first magnetic field between the first north pole face and the first south pole face is oriented opposite to a second magnetic field between the second north pole face and the second south pole face
Data Source
AI summary
A measurement device for determining an angular position, having a magnet device and a sensor device that are rotatable relative to one another. The magnet device has a first north pole face of a first magnetic north pole and a first south pole face of a first magnetic south pole. The magnet device has a second north pole face of a second magnetic north pole and a second south pole face of a second magnetic south pole. The sensor device is located in a region between the first north pole face and the first south pole face and between the second north pole face and the second south pole face. The sensor device has a first magnetic field sensor and a second magnetic field sensor. The first magnetic field sensor and the second magnetic field sensor are spaced apart from one another for ascertaining a magnetic field difference.