Magnetostrictive Displacement Sensor Dual Evaluation Unit
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Solution Overview
Problem
Existing magnetostrictive displacement sensors lack a redundant check for position signals, which is essential in safety-critical applications, as the signal evaluation only occurs in a single evaluation branch, preventing continuous diagnosis of sensor function and measurement quality.
Innovation Solution
A dual evaluation unit is introduced, featuring two branches to determine the time of flight for both position and reference signals, allowing for the detection of deviations and enabling redundant monitoring of position signals, with a processor unit to output error signals based on predefined threshold values, ensuring fail-safeness and continuous monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single evaluation branch is used for signal evaluation, then the device complexity is reduced, but the reliability and ability to perform redundant checks in safety-critical applications deteriorates
Solution Approach 1:
The evaluation circuit is segmented into multiple independent evaluation branches (first evaluation branch 38 and second evaluation branch 40), each capable of independently evaluating the measurement signal. This segmentation enables redundant checking of position signals while maintaining manageable complexity through modular design.
Solution Approach 2:
The measurement signal is copied and fed to multiple evaluation branches simultaneously. The first evaluation branch 38 and second evaluation branch 40 each receive and process identical copies of the measurement signal, enabling independent verification without requiring additional sensors or measurement paths.
2Measurement precision
If temperature compensation is implemented, then the measurement precision is improved, but the device complexity increases due to additional reference signals and evaluation processes
Solution Approach 1:
The evaluation branches are designed to perform multiple functions: they evaluate both the position signal for primary measurement and the reference signal for temperature compensation. This multi-functionality allows the same hardware to address both measurement precision and environmental compensation without proportionally increasing complexity.
Solution Approach 2:
The reference signal evaluation provides feedback about temperature-dependent variations and length variations of the magnetostrictive device component. This feedback is used to compensate for environmental effects on the position determination, improving measurement precision through continuous monitoring and correction.
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 setup allows for enhanced monitoring and error detection in magnetostrictive displacement sensors, enabling continuous diagnosis and improved reliability by comparing signal times of flight, thus ensuring accurate position determination and compensating for temperature and length variations.
Implementation Method 1
A mechanical pulse such as a mechanical longitudinal pulse and/or torsion pulse that moves along the measurement path in the form of a structure-borne sound wave can be generated in the magnetostrictive device component by interaction of the two magnetic fields at the location of the position magnet
Implementation Method 2
The transducer can, for example, comprise a coil or a piezoelectric measurement element
Data Source
AI summary
An evaluation unit for a magnetostrictive displacement sensor and a magnetostrictive displacement sensor for determining a position of at least one position encoder having an input for receiving an electrical measurement signal generated by the magnetostrictive displacement sensor are proposed. The electrical measurement signal includes a position signal representing a position of a position encoder movable relative to a magnetostrictive device component and a reference signal representing a reference position, having a first evaluation branch for evaluating the measurement signal. The first evaluation branch is adapted to determine a position signal time of flight of the position signal and a first reference signal time of flight of the reference signal.