Aircraft Control Surfaces for Dynamic Gust Load Alleviation
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Solution Overview
Problem
Existing methods for alleviating dynamic structural loads on aircraft due to gusts and turbulence are limited by control authority and fail to optimally manage peak loads, particularly in reducing wing bending accelerations and maintaining control surface authority.
Innovation Solution
A method and apparatus that dynamically detect disturbances, determine incidence angles, and generate control commands for ailerons, spoilers, and elevators to deflect control surfaces in a coordinated manner, adapting to both the incidence angle and gust length, ensuring optimal use of control authority to alleviate loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If rapid spoiler deflection is used to eliminate the first load peak from updraft gust, then the first load peak is reduced, but control authority is limited by reaction time and actuator power, and the second peak of wing bending acceleration may be increased
Solution Approach 1:
The invention divides the control function into two independent control systems: a first control system for turbulence alleviation using ailerons, and a second control system for gust load alleviation using spoilers. This segmentation allows each system to operate within its optimal control authority range without interfering with the other, resolving the limitation where single-system approaches fail to maintain adequate control authority.
Solution Approach 2:
The invention implements dynamic switching between different control modes based on the detected incidence angle. When the incidence angle exceeds a predetermined threshold indicating a gust event, the system transitions from turbulence-mode control to gust-mode control, optimizing the response strategy in real-time to maintain control authority under varying flight conditions.
2Reliability
If symmetric aileron actuation is used for gust load alleviation, then control problems are solved, but control authority is still limited
Solution Approach 1:
The invention separates gust load alleviation into two stages: primary control through symmetric aileron actuation for stability, and secondary control through spoiler deflection to augment control authority. This segmentation allows the system to maintain control stability while overcoming the inherent authority limitations of ailerons alone during severe gust conditions.
Solution Approach 2:
The invention merges the functionality of ailerons and spoilers into a coordinated dual-control system. The ailerons provide primary symmetric actuation for stability, while spoilers provide additional deflection authority. The combined action of both control surfaces synergistically increases overall control authority beyond what either system could achieve independently.
3Device complexity
If a single control system is used for both turbulence and gust alleviation, then system complexity is reduced, but optimal management of peak loads cannot be achieved
Solution Approach 1:
The invention segments the control system into two specialized subsystems: a first control system optimized for turbulence with continuous dynamic aileron actuation, and a second control system optimized for gusts with threshold-triggered spoiler deflection. This segmentation enables optimal peak load management by applying the appropriate control strategy for each disturbance type, rather than using a compromised single-system approach.
Solution Approach 2:
The invention implements feedback mechanisms where the incidence angle is continuously monitored and compared against predetermined thresholds. This feedback triggers appropriate control responses: continuous modulation for turbulence conditions and threshold-based activation for gust conditions. The feedback loop ensures optimal peak load management by adapting control authority to the actual severity and type of atmospheric disturbance detected.
Data Source
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AI summary
The invention provides a method of dynamically alleviating loads generated on an aircraft (2) by a disturbance of gust and/or turbulence, the method comprising the steps of: on a flight of the aircraft (2), a monitoring is applied for automatically detecting a disturbance due to gust and/or turbulence and determining an incidence angle of the disturbance; when a disturbance due to gust and/or turbulence is detected, automatically generating control commands (36; 32, 38, 40, 42) for deflecting control surfaces dependent on the incidence angle; and applying the control commands (36; 32, 38, 40, 42) to deflect the control surfaces. For optimizing the performance, it is proposed to conduct at least one of the following step sequences A) and/or B): A) adapting the control commands (36; 32, 38, 40, 42) not only to the amount of the incidence angle but also to the gust length in order to adapt the deflection of the control surfaces both to the incidence angle and the gust length; and/or B) generating first control commands (y, 34; 32, 38) for first control surfaces and second control commands (36; 32, 38, 40, 42) for second control surfaces, comparing the incidence angle with a predetermined value and generating the first control commands (y, 34; 32, 38) to actuate the first control surface until the incidence angle reaches this predetermined value and generating the second control commands (36; 32, 38, 40, 42) to add a deflection of the second control surfaces when the incidence angle is above the predetermined value.