Flap Slat Control Lever Redundancy for Reliable Signal Output
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Solution Overview
Problem
The existing flap slat control lever in aircraft high-lift systems faces challenges in achieving a failure probability of less than 1E-9 and providing optimal operating comfort, with traditional designs struggling to meet the increased safety and complexity requirements, particularly in dual-channel systems, and lacking in adjustable forces to enhance pilot feedback and ease of operation.
Innovation Solution
The improved flap slat control lever incorporates multiple redundancy measures, including dual displacement sensors and control command modules, which compare displacement signals within an error tolerance to ensure reliable operation, and a force sensor to adjust lifting and friction forces, ensuring the system can operate under various conditions and provide clear pilot feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional architecture FSCL is used, then device complexity is low, but reliability cannot achieve failure probability smaller than 1E-9
Solution Approach 1:
The patent applies local quality by implementing redundancy specifically in critical components (displacement sensors and control command modules) rather than throughout the entire system. The lifting force mechanism and friction force mechanism maintain traditional single-channel design, while only the detection and control modules use dual-channel redundancy, achieving high reliability where needed without unnecessary complexity elsewhere.
Solution Approach 2:
The control system is segmented into independent functional modules: first displacement sensor, second displacement sensor, first control command module, and second control command module. Each module operates independently with its own signal processing path, allowing failure isolation and enabling the system to maintain functionality even when one module fails, thus achieving the required 1E-9 failure probability.
2Reliability
If lifting force and friction force are increased, then lever can be locked within slot and perceptibility is provided, but operating comfort deteriorates and pilot burden increases
Solution Approach 1:
The patent introduces dynamic force adjustment through the force sensor and control command module. The lifting force mechanism and friction force mechanism forces are no longer fixed but can be dynamically adjusted based on real-time feedback from the force sensor. This allows the system to provide sufficient locking force when needed while reducing resistance during normal operation, thereby improving pilot comfort without compromising reliability.
Solution Approach 2:
A force sensor is integrated to provide real-time feedback on the forces acting on the lever. The control command module receives this feedback and adjusts the lifting force and friction force accordingly. This closed-loop feedback system ensures that the forces are optimized for both reliable locking and comfortable operation, preventing excessive forces that would burden the pilot while maintaining adequate locking reliability.
3Loss of information
If friction force is increased, then lever operation perceptibility is improved, but operating comfort deteriorates
Solution Approach 1:
The friction force mechanism is designed with dynamic adjustment capability, allowing the friction force to be varied based on operational requirements. During normal lever movement, the friction force is reduced to minimize resistance and improve ease of operation. During critical phases or when locking is required, the friction force is increased to provide perceptible feedback and ensure proper engagement, thus resolving the contradiction between perceptibility and ease of operation.
Data Source
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AI summary
A flap/slat control lever (200) and a method for operating the lever. The lever comprises: a first displacement sensor (204), used to detect displacement of the flap/slat control lever and to generate a first displacement detection signal; a second displacement sensor (205), used to detect the displacement of the flap/slat control lever and to generate a second displacement detection signal; a first control command module (CCM1), used to receive the first displacement detection signal; and a second control command module (CCM2), used to receive the second displacement detection signal, wherein the first control command module is in a standby state, and the second control command module is in an active state. The first control command module sends the first displacement detection signal to the second control command module. The second control command module compares the first and second displacement detection signals, and if the difference between the first and second displacement detection signals is within an acceptable error margin, the second control module sends the first or second displacement detection signal to a slat flap control computer (SFCC) to serve as a control signal for controlling operation of a flap and slat. The use of multiple displacement sensors and multiple control command modules ensures that a pilot can, under any anticipated operating conditions, operate a flap/slat control lever to output an available command signal to a high lift system, thereby reducing the likelihood of system failure.