Redundant Signal Processing Units with Divergent Operating Points
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Solution Overview
Problem
Existing redundant electronic systems in safety-critical environments face challenges in detecting common cause failures, where similar disturbances affect both redundant functional units, making it difficult to differentiate between single point and common cause failures through output signal comparison.
Innovation Solution
Configuring different operating points for redundant signal processing units and comparing their output signals to derive a failure indication, allowing for the detection of common cause failures without the need for additional disturbance measurement devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If redundant functional units are configured with identical operating points for simple comparison, then device complexity is reduced, but the ability to detect common cause failures deteriorates
Solution Approach 1:
The patent changes the operating point parameter of the redundant functional units. Instead of using identical operating points, at least one redundant unit is configured with a different operating point. This parameter change enables the detection of common cause failures because disturbances affecting both units will manifest differently in their output signals when operated at different operating points, making the failure detectable through comparison.
2Measurement precision
If additional disturbance measurement devices are added to detect common cause failures, then detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The redundant functional units themselves serve the dual purpose of performing the given function and detecting common cause failures. By configuring them with different operating points, their output signals can be compared to detect disturbances without requiring separate measurement devices. The system uses its own components to perform the detection function, eliminating the need for additional disturbance measurement devices.
Solution Approach 2:
The redundant functional units are designed to perform multiple functions: executing the primary signal processing task and simultaneously serving as sensors for detecting common cause failures. This multi-functionality is achieved by configuring them with different operating points, allowing their output signals to reveal disturbance information when compared, thus eliminating the need for separate detection devices.
Data Source
AI summary
A method for detecting a failure in an electronic signal processing system having a signal processing path comprises a configurable functional unit for performing a given function and at least one redundant version of the signal processing path including a corresponding configurable functional unit for performing the given function and configuring a first operating point for the functional unit in the signal processing path for performing the given function and configuring a second operating point for the corresponding functional unit in the redundant version of the signal processing path. The second operating point is different from the first operating point. The method further comprises applying a same input signal to the functional unit and the corresponding functional unit, comparing a first output signal produced by the functional unit with a second output signal produced by the corresponding functional unit, and deriving a failure indication from the comparing.