Magnetic Angle Sensor Self-Calibration Without Full Rotation
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Solution Overview
Problem
Magnetic angle sensors in applications where full rotations of the magnetic field do not regularly occur, such as in measuring steering angles in automobiles, face challenges with temperature compensation accuracy over the lifetime of the sensor due to aging effects, leading to calibration inaccuracies and parameter drifts, necessitating the use of guard bands.
Innovation Solution
The implementation of techniques to update temperature compensation functions based on collected sensor data during the lifetime of the sensor, allowing for improved accuracy of backend calibration and eliminating the need for guard bands by determining and updating calibration parameters using temperature compensation functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature compensation functions are not updated over the sensor's lifetime, then the device complexity remains low, but the measurement precision deteriorates due to aging effects and parameter drifts
Solution Approach 1:
The angle sensor performs self-calibration by automatically updating its own temperature compensation functions using collected sensor data, eliminating the need for external recalibration equipment and manual intervention. The sensor processes its own measurement data to detect parameter drifts and adjusts calibration parameters autonomously, making the system self-maintaining over its operational lifetime.
Solution Approach 2:
The sensor implements a feedback mechanism where measurement data collected over time is continuously analyzed to detect changes in calibration parameters. The system uses this feedback information to automatically update temperature compensation functions, creating a closed-loop system that maintains measurement accuracy by comparing current measurements against expected values and adjusting accordingly.
2Measurement precision
If full rotations are required for calibration, then the calibration accuracy can be maintained, but the ease of operation deteriorates in applications where full rotations do not occur
Solution Approach 1:
The calibration method transitions from a static requirement of full 360-degree rotations to a dynamic approach that adapts to the actual operational range of the sensor. The system dynamically determines calibration parameters based on the minimum and maximum angles observed during operation, allowing accurate calibration even when the magnetic field does not complete full rotations. This dynamic adaptation enables calibration in applications like steering angle measurement where the range is limited.
Solution Approach 2:
The invention changes the calibration parameters from requiring full rotational data to using temperature and angle range data. By shifting from rotation-based calibration to temperature-compensated calibration using min/max angle values, the system achieves accurate calibration without requiring the magnetic field to complete full rotations, thereby improving ease of operation while maintaining calibration accuracy.
3Reliability
If guard bands are used to account for calibration inaccuracies, then the reliability improves, but the measurement precision deteriorates due to reduced accuracy
Solution Approach 1:
The system performs preliminary calibration actions by continuously updating temperature compensation functions throughout the sensor's operational lifetime. By proactively detecting and correcting parameter drifts before they significantly degrade performance, the system maintains high measurement precision without needing guard bands. The continuous self-calibration eliminates the need for conservative offset additions that would otherwise be required to ensure reliability.
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 approach enhances the accuracy of magnetic angle sensor measurements over time by continuously adapting to temperature changes, reducing the reliance on guard bands and maintaining measurement precision without the need for frequent recalibration.
Implementation Method 1
The magnetic angle sensor may be a Hall-effect sensor
Implementation Method 2
The magnetic angle sensor may be a Hall-effect sensor, a magnetoresistive (MR) sensor
Implementation Method 3
The magnetic angle sensor may be a Hall-effect sensor, a magnetoresistive (MR) sensor, a variable reluctance sensor (VRS)
Data Source
AI summary
A device may obtain raw sensor data, collected by a sensing device, including a set of signal values and a set of temperature values corresponding to the set of signal values. The set of signal values may correspond to a magnetic field present at the sensing device. The device may determine, based on the set of signal values, a first value of a calibration parameter associated with calibrating the sensing device. The device may associate, based on the set of temperature values, a particular temperature value with the first value of the calibration parameter. The device may determine, based on the particular temperature value and a temperature compensation function associated with the calibration parameter, a second value of the calibration parameter. The device may selectively update the temperature compensation function based on a comparison of the first value and the second value.