Inductive Angular Sensor Offset Calibration via Six-Position Sampling
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Solution Overview
Problem
Existing inductive angular position sensor systems require complex and computationally intensive methods for determining calibration values for offset-compensation, which are inefficient and prone to inaccuracies.
Innovation Solution
A method involving a substrate with three receiver coils generating 120° phase-shifted signals, where a target is positioned at six predefined angles to calculate and store correction values using pairwise difference signals and sum of squares, allowing for efficient offset determination and compensation without mechanical movement of the target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing complex calibration methods are used for offset-compensation, then measurement precision may be maintained, but device complexity and computational intensity increase significantly
Solution Approach 1:
The calibration process is segmented into discrete steps with the target positioned at six specific angular positions (0°, 60°, 120°, 180°, 240°, 300°). This segmentation simplifies the complex continuous calibration problem into manageable discrete measurements, reducing computational intensity while maintaining accuracy.
Solution Approach 2:
The patent performs preliminary measurements at six predetermined angular positions before final calibration computation. By pre-positioning the target at these specific angles and collecting signal data in advance, the system reduces the computational burden during actual operation while ensuring accurate offset-compensation values are obtained.
2Measurement precision
If existing calibration methods are used, then offset-compensation accuracy may be achieved, but the calibration process becomes computationally intensive and time-consuming
Solution Approach 1:
The calibration method employs periodic action by measuring signals at six equally spaced angular positions around the full 360° range. This periodic sampling approach efficiently captures the necessary calibration data with minimal measurements, reducing calibration time while maintaining accuracy through the systematic repetition of the measurement cycle at each position.
3Reliability
If robust offset-compensation is implemented, then measurement reliability improves, but the algorithm complexity increases
Solution Approach 1:
The patent implements feedback by using the measured signals from the six angular positions to calculate offset-compensation values, which are then applied to correct the angular position measurements. This feedback mechanism ensures robustness against axial or radial position offsets by continuously refining the compensation based on actual measured data, improving reliability without excessive algorithmic complexity.
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 method simplifies the calibration process, reduces computational intensity, and improves accuracy by converging in a few iterations, providing effective offset compensation for inductive angular position sensors.
Implementation Method 1
The excitation coil may for example be excited with an AC signal, which induces eddy currents in the target
Implementation Method 2
The receiving coils will generate signals caused by the eddy currents in the target and the current in the transmitting coil
Implementation Method 3
The excitation coil may for example be excited with an AC signal, which induces eddy currents in the target
Data Source
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AI summary
A method of determining a set of calibration values (Aasym01, Aasym12, Aasym20) for offset-compensation of an inductive angular sensor arrangement comprising: a substrate with a transmitter coil and three receiver coils, and a rotatable target. The method comprises the steps of: a) exciting the transmitter coil; b) positioning the target at or near predefined positions, c) measuring and processing the signals, including calculating sums of squares of difference signals. A sensor device. An angular sensor system.