Ejection Sequencer Voting Logic for Fault-Tolerant Timing
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Solution Overview
Problem
Current ejection assembly sequencer systems lack the necessary accuracy and reliability in determining and controlling the timing sequences for deploying ejection seat subsystems, which can lead to increased risks of pilot injury due to potential unintentional or incorrect firing of ejection systems.
Innovation Solution
A sequencer system with multiple controllers (A-side and B-side) that determine initial and verified ejection sequences through comparisons, employing a two-out-of-three voting scheme to ensure consistency and redundancy, thereby preventing unintentional firing by matching sequence commands before activating ejection subsystems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single controller is used to determine ejection sequence timing, then the device complexity is low, but the reliability and accuracy of sequence timing are insufficient
Solution Approach 1:
The controller system is segmented into multiple independent controllers (first A-side controller, second A-side controller, first B-side controller, second B-side controller), each capable of independently determining initial ejection sequences. This segmentation allows the system to achieve higher reliability through redundancy while maintaining manageable complexity at each individual controller level.
Solution Approach 2:
Multiple copies of the controller are implemented, each performing the same function of determining initial ejection sequences. These copied controllers cross-compare their outputs to verify sequence accuracy, thereby improving reliability without significantly increasing the functional complexity of each individual controller unit.
2Measurement precision
If multiple controllers are used with cross-comparison voting scheme, then the accuracy and reliability of ejection sequence timing are improved, but the device complexity increases
Solution Approach 1:
A feedback mechanism is implemented where each controller receives and compares the initial ejection sequence determinations from other controllers. This cross-comparison feedback loop allows the system to verify timing precision through multiple independent assessments, improving measurement precision while distributing the computational complexity across multiple controllers.
Solution Approach 2:
Each controller independently determines an initial ejection sequence before final verification. This preliminary action by multiple controllers allows the system to perform cross-comparison and voting to establish the verified sequence, thereby improving timing precision through redundant preliminary assessments rather than relying on a single controller's determination.
3Reliability
If sequence commands are verified through cross-controller comparison, then the risk of unintentional firing is reduced, but the time required to determine the verified sequence increases
Solution Approach 1:
Multiple controllers simultaneously perform preliminary determination of initial ejection sequences before the verification stage. This parallel preliminary action reduces the total time required compared to sequential verification, while still maintaining safety through cross-comparison of all preliminary determinations to establish the verified sequence.
Solution Approach 2:
The system performs more determination actions than strictly necessary by having multiple controllers independently determine sequences, but this excessive action is efficient because it occurs in parallel. The cross-comparison then quickly identifies the verified sequence through voting, achieving safety against unintentional firing without excessive time loss.
Data Source
AI summary
A sequencer system for an ejection assembly may comprise a first A-side controller and a second A-side controller in operable communication with the first A-side controller. A first B-side controller may be in operable communication with the first A-side controller. A second B-side controller may be in operable communication with the first B-side controller and the second A-side controller. The controllers may be configured to each make an initial ejection sequence determination and a verified ejection sequence determination. The controllers may make the verified ejection seat determination based on a two of three voting scheme.