Aircraft Drive Arrangement with Synchronisation Shaft for Skew Prevention
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Solution Overview
Problem
Existing drive arrangements for aircraft wing control surfaces, which rely on synchronous movement and locking mechanisms, are inadequate for modern composite materials where flaps need to move independently and at different speeds to manage aerodynamic loads effectively, as they cannot prevent skew conditions and are heavy due to dual load path actuators.
Innovation Solution
A drive arrangement featuring first and second actuators with a common drive shaft, synchronisation shaft, and synchronisation arrangements that transmit loadings between flap ends in case of actuator failure, using a tubular synchronisation shaft to resist skewing and a brake to prevent uncontrolled movement, allowing independent flap operation while maintaining symmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate motor driven actuators with dual load path are used for each flap end, then reliability against skew conditions is improved, but weight increases significantly
Solution Approach 1:
The system divides the actuation function into two independent actuators (one at each end of the flap) connected by a synchronisation shaft. This segmentation allows each actuator to be simpler and lighter, while the distributed architecture maintains reliability through the synchronisation mechanism that prevents skew conditions.
Solution Approach 2:
A synchronisation shaft connects the two independent actuators, acting as an intermediary that transmits synchronisation signals and maintains coordination between them. This intermediary enables reliable skew prevention without requiring each actuator to independently handle full load paths, reducing individual actuator weight.
2Reliability
If known synchronous drive arrangements with locking mechanisms are used, then skew condition prevention is achieved, but adaptability for independent flap operation is lost
Solution Approach 1:
The synchronisation system dynamically adapts its behavior: during normal operation, the synchronisation shaft maintains coordination between actuators; during failure conditions, it allows independent operation. This dynamic adaptability enables the system to prevent skew conditions while still permitting independent flap operation when needed.
Solution Approach 2:
The system changes operational parameters based on conditions - normally maintaining synchronous operation through the synchronisation shaft, but capable of transitioning to independent operation when failure is detected or when asymmetric operation is required for aerodynamic reasons.
3Stability of the object's composition
If flaps are moved simultaneously at the same speed, then symmetry is maintained, but ability to manage aerodynamic loads on composite wings is reduced
Solution Approach 1:
The system dynamically adjusts flap operation modes - normally operating flaps symmetrically to maintain wing stability, but capable of asymmetric operation when required for aerodynamic load management on composite wings. The synchronisation mechanism adapts to allow different speeds and positions while maintaining overall system coordination.
Solution Approach 2:
Operational parameters such as flap position, speed, and timing are changed based on aerodynamic requirements. The system can transition from synchronous symmetric operation to asynchronous asymmetric operation, allowing optimized aerodynamic load management while maintaining the ability to restore symmetry when needed.
4Reliability
If dual load path actuators are used for each flap end, then reliability against uncontrolled movement is improved, but device complexity increases
Solution Approach 1:
The system segments the reliability function across two independent actuators with a synchronisation shaft, rather than requiring each actuator to independently handle full load paths. This segmentation reduces individual actuator complexity while maintaining overall system reliability through the distributed architecture.
Solution Approach 2:
The synchronisation shaft acts as an intermediary that coordinates the two independent actuators, providing a simple mechanical linkage that prevents uncontrolled movement and skew conditions without requiring complex control systems or dual load path mechanisms in each actuator.
Data Source
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AI summary
A drive arrangement comprising first and second actuators (24) arranged to drive respective output members (22) for movement, first and second synchronisation arrangements (34) associated with respective ones of the first and second actuators (24), and a synchronisation shaft (36) interconnecting the synchronisation arrangements (34).