Rotation Angle Measurement Using Dual Magnetic Sensor Systems
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Solution Overview
Problem
Current rotation angle measurement systems in the automotive industry face challenges in achieving high safety standards while being simple and cost-effective, particularly due to the need for redundancy and accurate measurement in harsh magnetic environments.
Innovation Solution
A method utilizing two distinct magnetic field sensor systems, one with Hall sensors and another with magnetoresistive sensors, to detect orthogonal magnetic field components, where a constant angle offset is calibrated and used to correct deviations, ensuring accurate rotation angle determination and minimizing stray field influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two different types of magnetic field sensors are used to provide redundancy, then safety and reliability are improved, but device complexity and cost increase
Solution Approach 1:
The patent combines two different magnetic field sensor systems (Hall effect sensors and magnetoresistive sensors) into a single integrated measurement system. The sensor unit contains both sensor types arranged to detect orthogonal magnetic field components, merging their functions to achieve ASIL D safety level while maintaining a compact structure. This resolving the contradiction by integrating redundancy within a unified device rather than separate systems.
Solution Approach 2:
The patent makes the sensor unit universal by enabling it to perform multiple measurement functions simultaneously. The first sensor system detects magnetic field components in one orientation while the second sensor system detects components in orthogonal orientations, allowing the single unit to provide redundant measurement capability for different magnetic field directions and types, thus achieving multi-functionality that improves reliability without proportionally increasing complexity.
2Reliability
If two different types of magnetic field sensors are used to provide redundancy, then safety and reliability are improved, but cost increases
Solution Approach 1:
The patent merges two different sensor technologies (Hall effect and magnetoresistive sensors) into a single manufactured unit. By integrating both sensor types in one package with shared support structures and signal processing, the patent achieves cost-effectiveness through economies of scale and reduced assembly complexity, while maintaining the safety benefits of redundant different-type sensors.
3Measurement precision
If sensor systems are arranged with constant angle offset, then measurement accuracy is improved through calibration, but device complexity increases due to calibration requirements
Solution Approach 1:
The patent applies preliminary calibration to establish a constant angle offset between the two sensor systems during manufacturing. This angle offset is determined in advance and stored as a calibration parameter, allowing the system to compensate for geometric differences between sensors without requiring complex real-time calibration procedures. The preliminary action of calibration simplifies subsequent operation while maintaining high measurement accuracy.
Solution Approach 2:
The patent changes the operational parameter by introducing a constant angle offset as a fixed calibration value. Instead of requiring dynamic adjustment or complex alignment procedures, the system uses a predetermined angular parameter that corrects for sensor arrangement differences. This parameter change transforms a potential source of error into a known, compensable quantity, improving measurement precision without adding operational complexity.
4Measurement precision
If deviation between sensor systems is minimized through modification of measured values, then measurement accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent modifies the measured values by applying a deviation correction based on the pre-determined angle offset. Instead of implementing complex iterative optimization algorithms, the system uses a straightforward parameter adjustment that compensates for angular differences between sensor systems. This parameter-based correction minimizes measurement deviation while keeping computational requirements minimal and suitable for real-time operation.
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 safety and cost-effectiveness by providing a redundant and accurate rotation angle measurement system, capable of compensating for sensor differences and environmental influences, while maintaining high precision and reliability.
Implementation Method 1
a first sensor system which comprises at least one magnetic field sensor of a first type, in particular a Hall sensor
Implementation Method 2
a second sensor system which comprises at least one magnetic field sensor of a second type, in particular a magnetoresistive sensor
Data Source
AI summary
A rotation angle measurement method and a circuit, a rotation angle measuring system including a shaft, a transducer, a first sensor system with at least one magnetic field sensor of a first type for measuring a magnetic field component Bz and a second sensor system with at least one magnetic field sensor of a second type for detecting magnetic field components Bx, By being provided, a first or second measured value being ascertained with the aid of each sensor system at a first point in time, a first or second rotation angle value being determined for each measured value, a first output rotation angle value being determined from the first rotation angle value and a known constant angle offset between the two sensor systems as a reference value for the second sensor system, a deviation of the second rotation angle value from the first output rotation angle value being ascertained.