Position Sensor Linearization Calibration for Air-Gap Variation
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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 mismatches between receiver coils, leading to inaccurate position detection in motor control systems.
Innovation Solution
A method for calibrating a linearization function by initializing correction factors at predetermined points, comparing with a reference signal, optimizing points with maximum error, and storing the function to correct sensor output, ensuring accuracy within predefined thresholds.
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, air gap inconsistencies, and coil mismatches
Solution Approach 1:
The patent applies parameter changes by introducing correction factors that modify the output signals of receiver coils based on pre-determined calibration data. These correction factors adjust for non-uniform electromagnetic fields, air gap variations, and coil mismatches, transforming the raw sensor outputs into accurate position measurements while maintaining magnetic field robustness
Solution Approach 2:
The patent implements preliminary action through a calibration process performed before actual operation. During calibration, the sensor system is exposed to known reference positions and correction factors are calculated and stored. This preliminary calibration enables the sensor to compensate for manufacturing tolerances and environmental variations during subsequent position measurement operations
2Measurement precision
If calibration parameters are calculated by matching electrical measured position with mechanical reference position, then measurement precision is improved, but device complexity increases due to additional calibration procedures
Solution Approach 1:
The patent applies self-service by enabling the position sensor system to perform its own calibration using internally generated test signals and stored correction factors. The system can automatically adjust its output based on pre-determined parameters without requiring external calibration equipment during normal operation, reducing the complexity of ongoing calibration procedures
Solution Approach 2:
The patent implements preliminary action by performing the complex calibration process once during manufacturing or initial setup. The calibration data is then stored in memory and reused during normal operation, eliminating the need for repeated complex calibration procedures and reducing long-term system 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
The method enhances the accuracy of position sensors by reducing maximum errors to acceptable levels, meeting Automotive Safety Integrity Levels (ASIL) for applications like autonomous driving.
Implementation Method 1
utilizing the physical principles of eddy currents or inductive coupling to detect the position of a target
Implementation Method 2
utilizing the physical principles of eddy currents or inductive coupling to detect the position of a target
Data Source
AI summary
A method for calibrating a linearization function for correcting the output of a position sensor providing a continuous output position signal, wherein the method optimizes the linearization function by defining optimal positions of the linearization points of the linearization function.