Inductive Position Sensor Linearization for Field Non-Uniformity
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Solution Overview
Problem
Inductive position sensors suffer from inaccuracies due to non-uniform electromagnetic fields, wire trace connections, air gap inconsistencies, and receiver coil mismatches, leading to inaccurate position detection.
Innovation Solution
A method for calibrating a linearization function by setting initial and final points, determining error vectors, and iteratively adding correction factors at maximum error positions to reduce inaccuracies, using interpolation between points for continuous signal correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inductive position sensors are used to provide robustness against magnetic fields, then reliability is improved, but measurement precision deteriorates due to non-uniform electromagnetic fields, wire trace connections, air gap inconsistencies, and receiver coil mismatches
Solution Approach 1:
The patent applies preliminary action by performing calibration before the sensor is put into service. A calibration process is executed that determines correction factors for the non-uniformities in the sensor system, allowing the sensor to compensate for its inherent imperfections before actual operation begins.
Solution Approach 2:
The patent implements feedback by using the output signal of the position sensor itself to determine calibration parameters. The sensor's output is fed back through a processing unit that analyzes the signal characteristics and calculates correction factors based on the observed deviations from ideal behavior.
2Measurement precision
If calibration parameters and linearization parameters are written into the position sensor to improve accuracy, then measurement precision is improved, but device complexity increases due to the need for calibration processes and parameter storage
Solution Approach 1:
The patent applies self-service by enabling the position sensor to perform its own calibration using its output signal. The sensor system includes a processing unit that automatically analyzes the sensor's output, determines calibration parameters, and stores them without requiring external calibration equipment or manual intervention.
Solution Approach 2:
The patent implements parameter changes by modifying the sensor's operating parameters through calibration. Correction factors are calculated and stored as new parameters that change the sensor's output characteristics, allowing the same hardware to achieve different levels of precision without physical modification.
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 method significantly improves position sensor accuracy by reducing errors, enabling compliance with Automotive Safety Integrity Levels (ASIL) for applications like autonomous driving.
Implementation Method 1
Inductive position sensors implement a magnet-free technology, utilizing the physical principles of eddy currents or inductive coupling to detect the position of a target that is moving above a set of coils
Implementation Method 2
Inductive position sensors implement a magnet-free technology, utilizing the physical principles of eddy currents or inductive coupling to detect the position of a target that is moving above a set of coils
Data Source
AI summary
A method for calibrating a linearization function for correcting an output of a position sensor providing a continuous output position signal is described. The method adds a new linearization point to the linearization function by detecting the maximum error at the output of the position sensor and applying the new linearization function to the output of the position sensor and repeat the adding new linearization points until all available linearization points have been defined.