Rotary Sensor Arrangement Failure Detection via Sum Difference Comparison
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Solution Overview
Problem
Conventional rotary sensor arrangements fail to reliably detect failures in magnetic field sensors or amplifying circuits, leading to erroneous angle determination, particularly in critical applications like automotive and security systems.
Innovation Solution
A failure detection concept that uses symmetrically arranged pairs of magnetic field sensors to generate sum and difference values, allowing for the determination of a failure status by comparing these values to thresholds, which can be performed in parallel with conventional angle determination and extends to multiple pairs of sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional rotary sensor arrangements use symmetrically arranged magnetic field sensors for angle determination, then angle measurement capability is achieved, but failure detection capability is insufficient
Solution Approach 1:
The patent makes the sensor arrangement multi-functional by enabling it to perform both angle determination and failure detection using the same sensor elements. The evaluation unit processes sensor signals to generate both angle information and failure status information, allowing a single system to serve multiple purposes without requiring additional dedicated failure detection hardware.
Solution Approach 2:
The patent implements preliminary failure detection by continuously monitoring sensor signals and comparing them against expected patterns before actual failures occur. The evaluation unit proactively identifies potential failures by analyzing signal characteristics, allowing the system to detect problems early and take preventive action before the failure affects angle measurement accuracy.
2Stability of the object's composition
If magnetic field sensors are arranged symmetrically to eliminate external magnetic field effects, then measurement robustness is improved, but the ability to detect sensor failures is reduced
Solution Approach 1:
The patent implements feedback by using the sensor signals for dual purposes: generating angle measurements and providing feedback for failure detection. The evaluation unit continuously analyzes the sensor signals, comparing actual readings against expected patterns based on the symmetric arrangement, and uses this feedback to identify when a sensor is malfunctioning while maintaining robust angle measurement capability.
3Device complexity
If the sensor arrangement processes signals for angle determination only, then processing simplicity is maintained, but fault coverage is insufficient
Solution Approach 1:
The evaluation unit is designed to be multi-functional, processing sensor signals to simultaneously determine rotation angles and detect failures. By extracting multiple types of information from the same sensor inputs through different processing paths, the system achieves enhanced fault coverage without proportionally increasing hardware complexity.
Solution Approach 2:
The patent changes the processing parameters by applying different evaluation methods to the same sensor signals. For angle determination, trigonometric functions are used, while for failure detection, the system analyzes signal patterns, magnitudes, and relationships between sensors. This parameter change allows the same hardware to achieve multiple objectives.
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
Enhances the reliability of failure detection, enabling the identification of faulty sensors or processing components, thereby ensuring accurate angle measurement and increasing fault coverage for automotive safety applications.
Implementation Method 1
magnetic field sensors, where the magnetic field sensors of the first pair are arranged symmetrically with respect to a rotation axis and are configured to provide a first and a second sensor value corresponding to the magnetic field generated by the magnetic source
Data Source
AI summary
A rotary sensor arrangement is configured to be used with a rotatable magnetic source and comprises a first and a second pair of magnetic field sensors, each pair arranged symmetrically with respect to rotation axes and providing respective sensor values. An evaluation unit determines a first sum value corresponding to a sum of the sensor values of the first pair, and a second sum value corresponding to a sum of the sensor values of the second pair. The evaluation unit further determines a difference value corresponding to a difference between the first and the second sum value and compares the difference value or a value derived thereof to a threshold value. Based on the comparison result, it is determined whether a failure status of the sensor arrangement is present.