Dynamic Control Surface Position Limits for Aircraft Load Alleviation
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Solution Overview
Problem
Current aircraft control surface designs are limited by static load calculations, leading to unnecessary structural reinforcement and weight, as they do not dynamically adjust to varying aircraft conditions such as speed, altitude, weight, and center of gravity, resulting in inefficient load management during extreme maneuvers.
Innovation Solution
A method and apparatus that use a computer system to identify dynamic position limits for control surfaces based on real-time operation parameters, such as airspeed, pitch, and load limits, to prevent excessive loads on aircraft structures during maneuvers, thereby reducing the need for additional structural reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If static load calculations are used to design control surfaces, then structural strength is ensured, but aircraft weight increases due to unnecessary structural reinforcement
Solution Approach 1:
The patent applies dynamics by transitioning from static load calculations to dynamic load management. The control surface position limits are no longer fixed but are dynamically adjusted based on real-time aircraft operating conditions including speed, altitude, weight, and center of gravity. This allows the structure to be designed for actual operational loads rather than worst-case static scenarios, reducing unnecessary structural reinforcement and aircraft weight while maintaining strength when needed.
Solution Approach 2:
The patent implements parameter changes by making the control surface position limits variable rather than constant. The limits are continuously modified based on changing aircraft parameters such as airspeed, altitude, weight, and center of gravity position. This enables the aircraft to operate with optimized structural design since the control surfaces will not exceed position limits that would generate loads beyond the reduced structural capacity.
2Force
If strict speed-based limits are applied to control surface movement, then load on control surfaces is reduced, but maneuverability is degraded
Solution Approach 1:
The patent resolves this contradiction through dynamics by implementing dynamic position limits that adapt to current flight conditions. Rather than applying strict speed-based limits that uniformly restrict control surface movement, the system calculates allowable position limits based on the specific combination of speed, altitude, weight, and center of gravity. This allows maximum maneuverability when conditions permit while preventing excessive loads when conditions require restraint, optimizing both load management and ease of operation.
Solution Approach 2:
The patent applies parameter changes by making the control surface position limits a function of multiple aircraft parameters rather than a simple speed-based constraint. The system continuously updates the position limits based on changes in speed, altitude, weight, and center of gravity, allowing the aircraft to achieve optimal maneuverability in each flight regime while maintaining load within safe boundaries.
3Strength
If additional structures are added to handle extreme maneuver loads, then structural strength is improved, but aircraft weight increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and establishing dynamic position limits that prevent excessive loads before they occur. The flight control system continuously monitors aircraft parameters and adjusts control surface position limits in advance to ensure loads remain within the capacity of the reduced structural design. This eliminates the need for additional structures to handle extreme maneuver loads, as the limits are set to prevent such loads from occurring in the first place.
Solution Approach 2:
The patent substitutes the mechanical approach of adding structural reinforcement with a control system approach. Instead of mechanically strengthening the aircraft structure to handle extreme maneuver loads, the system uses flight control laws and dynamic position limiting to manage loads through software-based control. This replaces the need for additional mechanical structures with an electronic control system that achieves the same protective function with minimal weight penalty.
Data Source
AI summary
A method for controlling control surfaces. A position limit is identified for movement of a control surface based on a load limit set for the control surface and a number of vehicle current operation parameters to form an identified position limit. Responsive to receiving a command to move the control surface on a vehicle to a new position, the control surface is commanded to move to a position within the identified position limit.