Reversible Decoupling Device for Aircraft Actuator Reliability
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Solution Overview
Problem
Conventional hydraulic actuators in aircraft can fail to maintain aerodynamic surface control in case of defects, leading to potential loss of aircraft controllability, and existing decoupling devices are either irreversible or difficult to test, ensuring functionality in emergency situations.
Innovation Solution
A reversible decoupling device for electromechanical actuators that allows for decoupling and recoupling, enabling continued operation of aerodynamic surfaces even with defective components, and can be tested regularly to ensure functionality, using a mechanism with a drive unit, force elements, and positive-locking elements to manage the change in length of the actuator element independently of the drive unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a decoupling device is integrated into the actuator element to enable continued operation after drive unit failure, then the reliability of aerodynamic surface control is improved, but the device complexity increases due to additional decoupling mechanisms
Solution Approach 1:
The actuator system is divided into two independent subsystems: the drive unit (first and second drive elements) and the decoupling device (with its own drive element, force elements, and positive locking elements). This segmentation allows the decoupling device to function independently when the drive unit fails, enabling the actuator element to be adjusted manually or by external forces while maintaining aerodynamic surface control.
Solution Approach 2:
The decoupling device is pre-configured with force elements (springs) and positive locking elements that are ready to engage automatically upon drive unit failure. The first positive locking element can lock the first drive element in place, preventing it from blocking the second drive element, thereby cushioning against the harmful effect of drive unit failure before it can compromise aerodynamic surface control.
2Reliability
If an irreversible decoupling device is used to ensure continued operation after failure, then the reliability is improved, but the ease of operation deteriorates because the device cannot be tested or reset
Solution Approach 1:
The decoupling device incorporates reversible positive locking mechanisms that can dynamically transition between locked and unlocked states. The first positive locking element can lock the first drive element during emergency operation, but the entire decoupling device can be reset by reversing the action of its drive element, allowing the system to alternate between operational and reset states for testing and maintenance purposes.
Solution Approach 2:
The decoupling device enables periodic testing of the actuator system by allowing controlled activation and deactivation of the decoupling mechanism. The reversible nature of the positive locking elements permits repeated cycling between coupled and decoupled states, facilitating regular functional tests to ensure emergency capabilities remain intact.
3Reliability
If the first positive locking element locks the first drive element to prevent blocking, then the reliability of the second drive element is improved, but the device complexity increases due to multiple locking mechanisms
Solution Approach 1:
The first positive locking element acts as an intermediary between the first and second drive elements. It selectively locks the first drive element only when necessary (upon failure detection) to prevent it from blocking the second drive element, while remaining unobtrusive during normal operation. This intermediary locking mechanism protects the critical second drive element without requiring complex continuous monitoring systems.
Data Source
Figure 1a~1b
Figure 2a
Figure 2b
AI summary
The present invention relates to actuator technology for aircraft. Conventionally, hydraulic actuators are used in aircraft because, even in the event of a fault, their mechanics usually do not become blocked, but rather essentially run freely due to the loss of hydraulic pressure. By using electromechanical actuators instead of hydraulic actuators, such free running cannot always be guaranteed. Accordingly, a reversible decoupling device (6) for an actuator element (3) with an energy storage element (22) is disclosed. This energy storage element is configured to store the energy required for decoupling within the decoupling device (6), but can be re-coupled after a successful test run, thus making the decoupling functionality easily testable.