SCAS Authority Reconfiguration After Aircraft Actuator Failure
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Solution Overview
Problem
Conventional Stability and Control Augmentation Systems (SCAS) are mechanically limited in authority, which restricts their ability to maintain control in the event of actuator failure, leading to undesired motion and loss of control authority.
Innovation Solution
A high authority stability and control augmentation system is implemented, utilizing dual flight control computers and actuators with self-checking capabilities, where each actuator receives dual commands from processors, allowing for automatic failure compensation and maintaining control authority by fixing the failed actuator in place and adjusting the other actuator's position to ensure continuous control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical limits are used to limit SCAS actuator authority, then the effects of actuator failure are mitigated, but the SCAS authority is reduced and cannot achieve full authority
Solution Approach 1:
The patent replaces mechanical limiting mechanisms (such as spring centers and mechanical stops) with a software-based control law that dynamically manages actuator authority. The mixing/mapping matrix and reconfiguration management tool use software logic to transfer authority from failed actuators to backup actuators, eliminating the need for physical mechanical limits while maintaining full SCAS authority through intelligent software control.
2Reliability
If mechanical limits are used to prevent undesired motion from actuator failure, then safety is improved, but the SCAS cannot achieve high authority
Solution Approach 1:
The patent substitutes mechanical safety mechanisms with a software-based reconfiguration management system that automatically detects actuator failures and redistributes control authority through the mixing/mapping matrix. This software-based approach provides both high automation and full safety without the authority limitations imposed by mechanical constraints.
Solution Approach 2:
The system continuously monitors actuator status and provides feedback to the reconfiguration management tool, which automatically adjusts the mixing/mapping matrix to maintain safe operation. This closed-loop feedback mechanism ensures safety while preserving full SCAS authority through dynamic software-based authority redistribution.
3Ease of operation
If spring mechanisms are used to recenter SCAS actuators upon failure, then actuator position is restored, but sudden recentering near extreme positions causes undesired motion
Solution Approach 1:
The patent replaces spring-based mechanical recentering mechanisms with a software-controlled authority transfer system. When actuator failure is detected, the mixing/mapping matrix and reconfiguration management tool smoothly redistribute authority to backup actuators, eliminating the sudden mechanical recentering action that causes undesired motion near extreme positions.
Data Source
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AI summary
The disclosure relates generally to flight control systems, and more specifically to an aircraft flight control system for allowing an augmentation system to have higher authorities, for example up to full authority, on an aircraft that has a mechanical flight control system. Embodiments include a flight control system for an aircraft, comprising: a first actuator; a first flight control computer having a first processor and a second processor for commanding the first actuator, wherein the first actuator compares commands from the first processor to commands from the second processor to find a first failure; a second actuator; and a second flight control computer having a first processor and a second processor for commanding the second actuator, wherein the second actuator compares commands from the first processor to commands from the second processor to find a second failure.