Aircraft Spoiler Droop Control With Mechanical Feedback Valves
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Solution Overview
Problem
Existing aircraft spoiler control systems face challenges in maintaining accurate position detection and load management during electrical and hydraulic failures, leading to potential damage from spoiler overlap with the wing flap during droop functions.
Innovation Solution
A system with a hydraulic actuator and mechanical device that detects the piston rod's position, using a pressure relief valve and anti-extension valve to manage load and prevent spoiler extension during failures, ensuring safe retraction and alignment with the wing surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the spoiler is actuated using a positive stroke of the actuator rod for extension, then the spoiler can be lifted to control speed and roll, but the system cannot achieve the droop function for lowering the spoiler relative to the wing
Solution Approach 1:
The patent applies inversion by enabling the actuator rod to perform both positive stroke (extension for spoiler lift) and negative stroke (retraction for spoiler droop). The mechanical feedback device detects rod position and the control system inverts the normal operation by allowing retraction beyond the zero position to achieve droop function, thus providing bidirectional control capability without requiring separate actuators
2Reliability
If the mechanical device provides load change based on piston rod position, then the system can manage loads during failures, but the device complexity increases
Solution Approach 1:
The patent implements feedback through a mechanical device that detects the piston rod position and provides mechanical feedback to the control system. This feedback mechanism enables the system to automatically adjust load management based on the actual spoiler position, improving reliability during failures by preventing unsafe operations without requiring complex external monitoring systems
Solution Approach 2:
The control system performs self-service by using the mechanical feedback from the piston rod position to automatically determine whether to apply load changes. The system self-regulates based on its own state information, eliminating the need for separate complex control mechanisms while maintaining failure safety
3Object-affected harmful factors
If the pressure relief valve switches to reduce load upon detection of retracted position, then damage risk is reduced during failures, but the response time and detection precision requirements increase
Solution Approach 1:
The patent applies preliminary action by having the mechanical device detect the piston rod position in advance and pre-position the pressure relief valve accordingly. When the rod is detected to be in the retracted position, the valve is already prepared to switch and reduce load immediately upon failure, preventing damage before it occurs rather than reacting after the fact
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 system effectively limits loads and prevents spoiler extension during failures, reducing the risk of damage to both the spoiler and wing flap, allowing for safe retraction and maintaining spoiler alignment, even in the absence of electrical or hydraulic power.
Implementation Method 1
The pressure relief valve may be operatively connected to the mechanical device and may be configured to switch from a first position to a second position upon detection that said piston rod is in the retracted position
Implementation Method 2
The anti-extension valve may be movable from a first position to a second position upon loss of said power, and wherein, in said second position said piston rod may be prevented from moving to said extended position unless a threshold pressure is reached in said retraction chamber
Data Source
AI summary
A system for detecting and controlling the position of a spoiler of an aircraft wing is described herein comprising: a hydraulic actuator having a piston rod operably connected to the spoiler, the piston rod being moveable between a retracted position, a neutral position and an extended position; and means for providing power to said hydraulic actuator; and a mechanical device for detecting whether the piston rod is in the retracted position, the neutral position or the extended position; and means, operatively connected to the mechanical device, that is configured to provide a change in a load applied to said hydraulic actuator, wherein said means is configured to change said load based on whether said piston rod is detected as being in said retracted position or said extended position.