Flight Control Surface EMA Modes to Prevent Free Float Drag
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Solution Overview
Problem
Existing flight control surface actuation systems using electro-hydraulic servo actuators (EHSAs) face inefficiencies due to bulky size, increased aerodynamic drag, and thermal management issues when both actuators fail, as they switch to a damped mode, leading to reduced control and increased drag.
Innovation Solution
The introduction of a third mode, 'blocked/blocked' mode in electromechanical actuators (EMAs) connected to flight control surfaces, allowing for controlled operation in active, stand-by, and blocked modes, with solenoids enabling the actuators to switch between these modes to manage thermal issues and reduce drag, and enabling the system to operate within a smaller size envelope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If electro-hydraulic servo actuators are used for flight control surface actuation, then the actuators can provide sufficient force and control authority, but the system becomes bulky and generates aerodynamic drag
Solution Approach 1:
The patent replaces electro-hydraulic servo actuators with electromagnetic actuators (EMAs), substituting a hydraulic-mechanical system with an electrical-mechanical system. This substitution eliminates hydraulic fluid, hoses, and associated components, significantly reducing actuator volume and eliminating aerodynamic drag from hydraulic systems while maintaining sufficient force output for flight control surface actuation
Solution Approach 2:
The patent changes the fundamental operating parameters of the actuator system by transitioning from hydraulic pressure-driven operation to electrical motor-driven operation. This parameter change enables more compact actuator design with reduced volume and weight while providing adequate force through electromagnetic conversion rather than hydraulic multiplication
2Reliability
If electro-hydraulic servo actuators with two-mode operation are used, then the system can operate in normal and failed modes, but thermal management becomes inefficient especially in dual failure scenarios
Solution Approach 1:
The patent introduces a dynamic three-mode operation system for EMAs that adapts to different failure scenarios. The modes include: normal operation mode (both actuators active), single failure mode (one actuator active, one in standby), and dual failure mode (both actuators in blocked/anti-extension mode). This dynamic adaptation optimizes thermal management by blocking actuators in dual failure scenarios, preventing unnecessary heat generation from failed motors while maintaining reliability through appropriate mode switching
Solution Approach 2:
The patent implements beforehand cushioning by providing standby EMAs that can take over in case of failure. The standby EMAs are pre-configured and can be quickly activated or switched to blocked mode to prevent thermal issues. This preparatory arrangement ensures thermal management efficiency is maintained even when failures occur, as the system can switch to blocked mode before excessive heat builds up
3Reliability
If traditional two-mode EMA operation is used, then the system can handle single failures, but cannot effectively prevent free float and drag in dual failure scenarios
Solution Approach 1:
The patent implements dynamic mode switching with three distinct operational states: normal mode (both EMAs active), single failure mode (one EMA active, one in standby), and dual failure mode (both EMAs in blocked/anti-extension mode). This dynamic adaptation allows the system to respond appropriately to different failure scenarios, specifically preventing free float and aerodynamic drag in dual failure scenarios by blocking both actuators rather than allowing them to float freely
Solution Approach 2:
The patent applies preliminary anti-action by implementing blocked/anti-extension mode that prevents harmful free float and aerodynamic drag before they can occur. In dual failure scenarios, the system proactively blocks both EMAs in the anti-extension mode, preventing the actuator rods from moving freely and generating drag, thus counteracting the harmful effects before they manifest
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
This solution reduces the size of the EMA system, minimizes aerodynamic drag, and enhances thermal management by allowing the system to operate effectively even when one or both EMAs fail, maintaining control and reducing heat generation, thus improving performance and efficiency.
Implementation Method 1
said first EMA comprises a first Motor Drive Electronics (MDE) and a first solenoid and said second EMA comprises a second MDE and a second solenoid
Data Source
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AI summary
A system for controlling a flight control surface (260) is described herein, wherein said system comprises: a first electromagnetic actuator "EMA" (210) and a second EMA (220), each of which are connected to said flight control surface (260); and wherein each EMA (210, 220) is configured to be arranged in, and switched between, three modes; said three modes comprising: an active mode, a stand-by mode and a blocked, or anti-extension, mode. A method for controlling the flight surface is also described.