Aircraft Flight Control Actuator Load Management
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Solution Overview
Problem
Current flight control systems in aircraft face significant loads during pre-flight and maintenance checks, leading to increased fatigue and potential redesign requirements, which can be costly and time-consuming, due to the need to manage redundant actuation systems and mitigate force mismatches and bottoming loads.
Innovation Solution
A method and apparatus that limit the travel and rate of actuators in flight control systems when the aircraft is on the ground and below a certain speed threshold, using a control law to reduce loads on actuators and prevent force mismatches and bottoming loads, thereby extending the life of components and reducing maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control checks are performed by moving actuators to full travel stops during pre-flight and maintenance, then freedom of movement and full travel verification are achieved, but large fatigue loads are generated on the actuation system
Solution Approach 1:
The patent changes the operational parameters of actuators during control checks by limiting travel distance and rate. Instead of moving actuators to full travel stops, the system moves them only a limited distance at a limited rate, thereby verifying freedom of movement while significantly reducing the fatigue loads generated on the actuation system.
2Reliability
If redundant actuation systems are operated simultaneously during control checks, then control surface movement is verified, but force fights and bottoming loads occur between actuators
Solution Approach 1:
The patent applies preliminary action by sequentially activating actuators rather than operating them simultaneously. The system activates one actuator at a time in a predetermined sequence, allowing each actuator to reach its commanded position without opposing forces from other actuators. This eliminates force fights and bottoming loads while still verifying the functionality of the redundant actuation system.
3Strength
If actuator travel is limited during control checks, then fatigue loads are reduced, but verification of full travel may be compromised
Solution Approach 1:
The patent employs feedback mechanisms to monitor actuator position, travel distance, and rate during control checks. The system continuously measures these parameters and compares them against predetermined thresholds. This feedback allows the system to verify that actuators are moving freely and functioning correctly within the limited travel and rate constraints, without requiring full travel to end stops.
Data Source
AI summary
A method, apparatus, and computer program product for managing movement of a flight control surface on an aircraft. A control signal is received to move the flight control surface to a position. Travel in a number of actuators in a plurality of actuators coupled to the flight control surface is limited to an amount that reduces a load on the number of actuators in the plurality of actuators in response to receiving the control signal while the aircraft is on the ground and the speed of the aircraft is less than a threshold.