Flight Control Surface Deployment With Actuator Force-Fight Control
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Solution Overview
Problem
The deployment of flight control surfaces in aircraft results in 'force fight' due to differences in actuator movement, leading to fatigue and requiring larger, heavier designs to account for this stress.
Innovation Solution
A method and system that control actuator displacement by limiting acceleration during the initial deployment period and adjusting actuator speed, using a force fight controller and acceleration limiter to synchronize actuator movement and reduce peak force fight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple actuators are engaged to the same flight control surface, then the flight control surface can be actuated, but force fight occurs due to differences in actuator movement causing fatigue
Solution Approach 1:
The system uses feedback from actuator position sensors to continuously monitor and adjust actuator movement. The control system receives position information from each actuator and modifies control signals to ensure synchronized movement, eliminating force fight while maintaining reliable actuation of the flight control surface
Solution Approach 2:
The system dynamically adjusts actuator speed and position in real-time based on feedback signals. By making the actuator system adaptive and responsive to actual position differences, the system maintains coordination under varying operational conditions without requiring oversized components for fatigue resistance
2Reliability
If actuators are designed to account for force fight fatigue, then reliability is improved, but the actuators and flight control surfaces become bigger and heavier
Solution Approach 1:
By implementing feedback control that actively eliminates force fight, the system removes the need to design oversized actuators and flight control surfaces with excessive fatigue margins. The feedback ensures synchronized actuator movement, allowing components to be optimized for performance rather than oversized for fatigue resistance
Solution Approach 2:
The system changes the operational parameters of the actuators by dynamically adjusting speed and position commands based on real-time feedback. This allows the actuators to operate in a coordinated manner that eliminates force fight, enabling lighter component designs that would otherwise require increased mass to withstand fatigue from uncoordinated movement
3Productivity
If actuator speed is increased during deployment, then productivity is improved, but acceleration differences between actuators increase force fight
Solution Approach 1:
The feedback control system monitors actuator positions and adjusts control signals to maintain synchronized movement even at high deployment speeds. By continuously comparing actual positions with target positions and making real-time corrections, the system achieves fast deployment without the acceleration differences that cause force fight
Solution Approach 2:
The system dynamically coordinates actuator acceleration and speed profiles to maintain synchronization throughout the deployment process. By making the actuator system adaptive to actual movement conditions, it enables high productivity through fast deployment while eliminating force fight that would otherwise occur at higher speeds
Data Source
AI summary
A system and method for deploying a flight control surface. The method includes displacing actuators engaged with the flight control surface during an initial period wherein each actuator displaces from zero speed to a deployment speed, and during a deployment period after the initial period. The method includes during the deployment period, controlling displacement of at least one of the actuators in response to actuator status information received therefrom. The method includes during the initial period, limiting an acceleration of said actuator from the zero speed to the deployment speed. The system has a control unit with a force fight controller and an acceleration limiter.