Redundant Sensor Fault Detection With Dynamic Uncertainty Limits
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Solution Overview
Problem
Existing redundant sensor systems face challenges in accurately detecting faults due to differences in sensor responses caused by variations in operating temperature, power supply, and signal levels, which can degrade system performance and increase costs.
Innovation Solution
A sensor apparatus comprising a combiner and comparator that modify a dynamic limit based on the uncertainties of individual sensor outputs, allowing for increased resolution and fault detection even with wider range sensors, using averaging and comparison techniques to reduce errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sensors are operated over a wider range away from nominal operating points, then sensor versatility and range are improved, but measurement precision and fault detection resolution deteriorate due to increased errors
Solution Approach 1:
The patent combines multiple sensor outputs through a combiner circuit that averages the signals from multiple sensors. This merging approach reduces individual sensor errors and uncertainties, allowing the system to maintain high measurement precision even when operating sensors over a wider range away from nominal operating points.
Solution Approach 2:
The patent introduces a dynamic limit as an intermediary parameter that mediates between the sensor output and fault detection threshold. This dynamic limit adapts based on the average of individual sensor uncertainties, providing a flexible comparison reference that maintains fault detection resolution across varying operating ranges.
2Reliability
If multiple sensors are used with redundancy, then reliability and fault detection capability are improved, but differences in operating conditions cause measurement discrepancies that complicate fault identification
Solution Approach 1:
The patent applies local quality by individually evaluating each sensor's uncertainty characteristics and incorporating them into the overall fault detection process. Each sensor's output is assessed with its own uncertainty parameters (noise, bias, scale errors), allowing the system to account for local variations in sensor performance due to different operating conditions.
Solution Approach 2:
The patent introduces dynamic limits that adapt based on the average uncertainty of individual sensors. This dynamic approach allows the fault detection threshold to automatically adjust according to current sensor operating conditions, simplifying the comparison process while maintaining high reliability across varying environmental conditions.
3Measurement precision
If sensor uncertainties are accounted for in fault detection, then measurement precision is improved, but the complexity of determining and applying dynamic limits increases
Solution Approach 1:
The patent changes the parameter used for fault detection from a fixed threshold to a dynamic limit that is calculated as a function of sensor uncertainties. By expressing the dynamic limit in terms of fundamental sensor parameters (noise, bias, scale errors), the system achieves high measurement precision while keeping the calculation methodology systematic and manageable.
Data Source
AI summary
Aspects of the present disclosure provide apparatuses for minimizing the impacts of differences in sensor measurements while sensors are being used. An apparatus in accordance with an aspect of the present disclosure may comprise a first sensor, a second sensor, a combiner, coupled to the first sensor and the second sensor, and a comparator, coupled to the first sensor and the second sensor, wherein the combiner and comparator modify a dynamic limit of the apparatus based at least in part on a first uncertainty in a first output of the first sensor and a second uncertainty in a second output of the second sensor.