Aircraft Dynamic Stability Margin Calculation via Incidence Oscillation
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Solution Overview
Problem
Existing methods for determining the dynamic stability margin of an aircraft are prone to variability based on the aircraft's balance position, leading to inaccuracies in calculating the maneuver point, which affects flight control and safety.
Innovation Solution
A method and device that measure the angular velocity of incidence oscillation to calculate the dynamic stability margin and maneuver point position, using equations that account for the aircraft's mass, inertia, and aerodynamic coefficients, providing a more accurate and position-independent determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If theoretical equations with constant aerodynamic coefficients are used to determine the maneuver point, then the calculation is simple, but the position of the maneuver point varies with aircraft balance position leading to inaccuracy
Solution Approach 1:
The patent changes the approach from using constant aerodynamic coefficients to using measured angular velocity as a variable parameter. By measuring the angular velocity of incidence oscillation and using it in the determination equations, the system adapts to different aircraft balance positions and flight conditions, thereby improving accuracy without significantly increasing complexity
Solution Approach 2:
The patent introduces feedback by measuring the actual angular velocity of incidence oscillation and using this measured value to determine the maneuver point position. This closed-loop approach allows the system to compensate for variations in aircraft balance position, ensuring accurate determination of the maneuver point regardless of center of gravity location
2Adaptability or versatility
If the center of gravity position is allowed to vary within the authorized range, then the aircraft balance flexibility is improved, but the maneuver point position becomes variable affecting flight control safety
Solution Approach 1:
The patent transitions from a static determination method to a dynamic one by continuously measuring the angular velocity of incidence oscillation during flight. This dynamic measurement approach allows the system to accurately determine the maneuver point position regardless of where the center of gravity is located within the authorized range, maintaining flight control safety while preserving balance flexibility
Solution Approach 2:
The system uses the aircraft's own natural incidence oscillation characteristics to determine the maneuver point position. By measuring the angular velocity of the aircraft's natural oscillations and using this information in the determination equations, the system self-adjusts to different balance positions without requiring external calibration or manual intervention
Data Source
AI summary
A method of determining a dynamic stability margin MSD of an aircraft includes calculating the longitudinal position XMP of a maneuver point MP to find the distance between the maneuver point and the position XCG of the aircraft center of gravity CG, as a function of the angular velocity ωO of an incidence oscillation of the aircraft. A device for determining the dynamic stability margin MSD or a position XMP of the maneuver point MP includes means or acquisition of data and or calculating a dynamic stability margin. The means receive data for generating, the aircraft mass m and pitch inertia Iyy; the flight speed V; the angular velocity ωO of the incidence oscillation at a flight point; a coefficient C*α representing Czα of a “quasi-static” model of the aircraft. The aircraft flight control laws may be adapted according to the stability margin and to XMP.