Three-Lane Remote Electronic Unit With Bit-For-Bit Voting
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Solution Overview
Problem
Existing remote electronic units (REUs) in fly-by-wire systems face challenges in maintaining high integrity of control signals due to susceptibility to faults, leading to potential loss of actuator control, especially when generic faults occur in processing elements, and current redundancy solutions are costly and technologically challenging.
Innovation Solution
Implementing a three-lane architecture in REUs with dissimilar processing elements, utilizing bit-for-bit matching and synchronization mechanisms to ensure identical output data, and incorporating fault detection and protection mechanisms to maintain actuator control integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional redundancy solutions are implemented in REUs, then reliability is improved, but device complexity and cost increase significantly
Solution Approach 1:
The processing element is divided into three independent processing lanes, each capable of independently processing control signals. This segmentation allows parallel processing while maintaining simplicity of each individual lane, achieving reliability through distribution rather than complex redundancy architecture
Solution Approach 2:
Each processing lane is designed with dissimilar characteristics to others, creating local differences in processing paths. This ensures that a fault in one lane does not propagate to others, providing fault isolation while keeping each lane relatively simple
2Reliability
If dissimilar processing elements are used in three-lane architecture, then fault tolerance is improved, but manufacturing complexity increases
Solution Approach 1:
The processing lanes are made dissimilar by varying operational parameters such as clock frequencies, processing speeds, or algorithmic approaches rather than using fundamentally different hardware architectures. This allows fault tolerance through parameter diversity while maintaining compatibility with standard manufacturing processes
3Reliability
If bit-for-bit matching and synchronization mechanisms are implemented, then output integrity is improved, but hardware usage increases
Solution Approach 1:
A voter mechanism compares outputs from all three processing lanes and selects the correct output based on majority voting or discrepancy detection. This feedback mechanism ensures bit-for-bit matching and synchronization while using minimal additional hardware compared to complex synchronization protocols
Data Source
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AI summary
Remote electronic units effective to generate output data for an actuator are described. A remote electronic unit may include first, second, and third lanes. The first, second, and third lanes may receive input data including an actuator command. The first, second, and third lanes may generate first, second, and third output data, respectively, based on the input data. The first, second, and third lanes may respectively send the first, second, and third output data to a voter. The first and second lanes may respectively send the first and second output data to a multiplexer. The voter may output a selection signal to the multiplexer if at least two out of the first, second, and third output data are identical. The multiplexer may select one of the first and the second output data based on the selection signal and transmit the selection to the actuator via an actuator control electronics.