Aerospace Actuator Failsafe Deployment Control
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Solution Overview
Problem
Existing electrically powered actuators for aerospace applications lack a failsafe operating mode and damping function to control the rate of deployment, which is critical for ensuring the landing gear can be deployed safely and efficiently in case of system failures.
Innovation Solution
An actuator design incorporating a first and second actuator arrangement with brake and damping means, where the second and third components are secured to form an inner sleeve, allowing relative axial movement, and the outer sleeve carries a nut co-operable with the threaded inner sleeve, enabling controlled extension through a damping mechanism, such as a ratchet or magnetic damping device, to manage the rate of deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrically powered actuator is used to replace hydraulic actuators, then weight and complexity are reduced and reliability is improved, but the ability to control the rate of deployment in failsafe mode is lost
Solution Approach 1:
The patent employs nested actuator arrangements where an inner actuator is positioned within an outer actuator. The inner actuator includes an inner shaft, inner sleeve, and first nut, while the outer actuator contains an outer shaft, outer sleeve, and second nut. This nesting allows both actuators to operate independently or together, providing controlled deployment rates even when one fails, thus maintaining ease of operation while improving reliability.
Solution Approach 2:
The patent incorporates a brake mechanism that can dynamically switch between engaged and disengaged states. When the brake is engaged, it prevents rotation of the actuator components, controlling the deployment rate. When disengaged, full deployment speed is achieved. This dynamic control allows the system to maintain deployment rate control capability while using electric actuators for improved reliability.
2Reliability
If a failsafe mode is added to the actuator, then the ability to deploy landing gear on failure is improved, but device complexity increases
Solution Approach 1:
The patent divides the actuator system into segmented components: an inner actuator arrangement and an outer actuator arrangement, each with their own shafts, sleeves, nuts, and ball-screw mechanisms. This segmentation allows independent operation of each actuator, so if one fails, the other can still provide failsafe deployment capability without requiring a completely redundant separate system.
Solution Approach 2:
The brake mechanism serves multiple functions: it controls the deployment rate during normal operation, it enables failsafe mode by preventing rotation when engaged, and it can be selectively applied to either the inner or outer actuator. This multi-functionality reduces the need for separate dedicated failsafe mechanisms, thereby limiting the increase in device complexity.
3Ease of operation
If damping means is added to control the rate of extension, then deployment control is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical damping mechanisms with a simpler brake-based system. Instead of using viscous dampers, shock absorbers, or complex spring-mass systems, the invention uses a brake that can be engaged or disengaged to control the deployment rate. This substitution maintains deployment control capability while significantly reducing the complexity of damping components.
Solution Approach 2:
The brake mechanism changes the operational parameters of the actuator by controlling the friction between brake pads and the rotating components. By adjusting the brake engagement level, the deployment rate can be controlled without adding complex variable damping mechanisms. This parameter-based control simplifies the overall device structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The actuator ensures reliable deployment of landing gear by engaging a failsafe mode that controls the rate of extension, even in case of motor or damping mechanism failures, utilizing a brake and damping mechanism to manage the movement under gravity, thereby ensuring safe and controlled operation.
Implementation Method 1
brake means operable to prevent extension of the first and/or second actuator arrangement
Implementation Method 2
damping means operable to control the rate of extension of at least one of the first and second actuator arrangements
Data Source
Figure 1~3
Figure 4
Figure 5~6
AI summary
An actuator comprises a first actuator arrangement operable to allow relative axial movement to occur between a first component (16, 44) and a second component (18, 46), a second actuator arrangement operable to allow relative axial movement to occur between a third component (28, 48) and a fourth component (26, 50), brake means (30, 52, 66) operable to prevent extension of the first and/or second actuator arrangement, and damping means (72) operable to control the rate of extension of at least one of the first and second actuator arrangements.