Sensor Testing via Inductive Coupling Plausibility Checks
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Solution Overview
Problem
Sensors, particularly in safety-critical applications like the motor vehicle industry, face challenges in maintaining reliability when subjected to unusual conditions such as mechanical damage or material fatigue, where redundancy may not effectively compensate for errors affecting both primary and secondary components, leading to a loss of safety margin.
Innovation Solution
A procedure involving the calculation of sensor output signals based on the coupling between primary and secondary inductances, with additional electrical signals being compared to limits to determine faulty states, allowing for precise adaptation to safety requirements and increased robustness with minimal effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant components are implemented in the sensor, then safety with respect to many safety-critical influences is increased, but safety against common failures affecting both primary and secondary components is not improved
Solution Approach 1:
The patent applies preliminary action by performing a plausibility check on the sensor output signal before final evaluation. The method calculates whether the output signal is plausible based on the electrical quantity and limit value comparison, preventing faulty signals from being processed further. This preliminary validation step ensures that common failures affecting both primary and secondary components are detected before they can compromise system safety.
2Ease of operation
If the sensor output signal is used directly without additional validation, then the system is simpler to operate, but the system cannot detect when the sensor has been removed or is ineffective
Solution Approach 1:
The patent implements feedback by comparing the sensor output signal with a plausibility criterion derived from the electrical quantity and limit value. This feedback mechanism continuously validates whether the sensor signal is reasonable and detects when the sensor has been removed or is ineffective. The system automatically identifies faulty states through this feedback loop without requiring complex additional validation systems.
3Reliability
If a quotient or sum of secondary coil voltages is compared with a reference value, then some fault detection is achieved, but the method cannot distinguish all faulty conditions from normal operation
Solution Approach 1:
The patent applies parameter changes by utilizing the electrical quantity (such as voltage or current magnitude) and comparing it with a dynamically determined limit value. This approach changes the parameter being monitored from simple voltage quotients to a more comprehensive electrical quantity that provides better discrimination between faulty and normal states. The limit value comparison enables precise distinction between different operational states including faulty conditions.
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 sensor safety by accurately detecting faulty states, even when errors affect both components, thereby ensuring increased reliability and robustness with reduced complexity.
Implementation Method 1
a sensor with a primary inductance (4) that is galvanically isolated from a first and second secondary inductance (5, 6) which are inductively coupled to the primary inductance (4)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a method for testing a sensor having a primary inductance (4), which is galvanically separated from a first and second secondary inductance (5, 6), each inductively coupled to the primary inductance (4), comprising: calculating a sensor output signal (epos), wherein the sensor output signal (epos) is dependent on the coupling between the primary inductance (4) and the first secondary inductance (5) and between the primary inductance (4) and the second secondary inductance (6), determining a first electrical value (|Uprim |, |IEprim |, esum, edif), which is different from the sensor output signal (epos), comparing the first electrical value (|Uprim |, |IEprim |, esum, edif) to a first limit value (sl), in order to determine whether the sensor is in a faulty state The invention further relates to a corresponding apparatus and to a sensor having the apparatus.