Magnetic Position Sensor Gradients for Disturbance-Resistant Fault Detection
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Solution Overview
Problem
Magnetic position sensor systems face challenges in harsh environments due to electromagnetic disturbances, requiring accurate position determination while also detecting faults such as mechanical defects and ensuring functional safety.
Innovation Solution
A magnetic position sensor system using a magnetic field source and a sensor device with at least three magnetic sensitive elements to measure magnetic field values, gradients, and differences, deriving both position and fault signals, insensitive to external disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic position sensor systems are used in harsh environments, then position measurement capability is maintained, but susceptibility to electromagnetic disturbance signals increases
Solution Approach 1:
The system segments the magnetic field measurement into multiple independent components (at least three magnetic field values from separate sensitive elements). By measuring multiple field components and processing them through gradient calculation, the system can distinguish between actual position changes and external disturbance signals, thereby maintaining measurement precision while reducing disturbance sensitivity.
Solution Approach 2:
The system implements a feedback mechanism where the processed magnetic field gradients are continuously monitored to derive both position information and integrity signals. The integrity signal provides feedback about system health and disturbance levels, enabling the system to adapt and maintain accurate position measurement even in harsh electromagnetic environments.
2Reliability
If fault detection capability is added to position sensor systems, then functional safety is improved, but system complexity increases
Solution Approach 1:
The system achieves multi-functionality by using the same magnetic sensitive elements and processing circuitry to perform both position measurement and fault detection. The at least three magnetic field values are processed to generate both position signals and integrity signals, eliminating the need for separate fault detection hardware and reducing overall system complexity while improving functional safety.
Solution Approach 2:
The system performs self-diagnosis by monitoring its own magnetic field measurements and processing outputs. The integrity signal is generated automatically from the same measurement data used for position determination, allowing the system to self-assess its health status and detect faults without external monitoring equipment, thereby improving reliability without adding complexity.
3Measurement precision
If multiple magnetic field values are measured to determine position, then position accuracy is improved, but processing requirements increase
Solution Approach 1:
The system extracts only the essential information needed for position determination by calculating magnetic field gradients from the multiple measured field values. Instead of processing all raw measurement data, the system extracts gradient information which contains the position-relevant data while filtering out redundant information, thereby reducing processing power requirements while maintaining position accuracy.
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
Provides accurate position information and fault detection, enhancing system integrity and safety in harsh environments like automotive, industrial, and robotic applications.
Implementation Method 1
a magnetic field source for generating a magnetic field; a position sensor device movable relative to the magnetic field source or vice versa
Data Source
AI summary
A position sensor system includes a magnetic source for generating a magnetic field, and a position sensor device movable relative to the magnetic source, or vice versa. The position sensor device comprises at least three magnetic sensor elements for measuring at least three magnetic field values of the magnetic field, and a processing circuit configured for determining at least two magnetic field gradients or magnetic field differences based on the at least three magnetic field values, and for deriving from the at least two magnetic field gradients or differences a first value indicative of a position of the position sensor device, and for deriving from the at least two magnetic field gradients or differences a second value indicative of integrity of the position sensor system.