Vibration-Based Vortex Ring State Detection for Rotary-Wing Aircraft
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Solution Overview
Problem
Current methods for detecting the approach of a vortex ring state in rotary wing aerodynes are inadequate, leading to uncertainty and increased risk of accidents due to the lack of accurate and real-time measurement of airspeed and influencing parameters, with existing solutions relying on flawed state estimators or indirect measurements.
Innovation Solution
A device comprising a set of vibration sensors distributed along the longitudinal and vertical axes of the aerodyne, connected to a data processing unit that calculates the vibration spectrum in real-time, allowing for direct detection of the vortex ring state through vibration analysis and issuing an alarm before entry, thereby providing a timely warning to the pilot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If state estimators or indirect measurements are used to detect vortex ring state, then the detection system is simpler, but the measurement precision and reliability are insufficient
Solution Approach 1:
The patent replaces traditional mechanical/indirect measurement systems (state estimators, airspeed sensors) with a vibration-based detection system. Vibration sensors mounted on the rotor hub directly measure mechanical vibrations caused by vortex ring state, providing more precise and reliable detection without requiring complex aerodynamic models or indirect calculations.
Solution Approach 2:
The patent introduces vibration sensors as an intermediary measurement mechanism. Instead of directly measuring airspeed or vortex characteristics, the system measures rotor hub vibrations that serve as an intermediate indicator of vortex ring state, enabling indirect yet accurate detection of the dangerous flight condition.
2Reliability
If safety margins are increased to account for vortex domain uncertainty, then the reliability improves, but the flight domain considered as safe is reduced
Solution Approach 1:
The patent enables preliminary detection of vortex ring state approach through characteristic vibration patterns before the actual dangerous condition develops. By detecting vibrations that precede full vortex entry, the system provides early warning that allows pilots to take corrective action, maintaining reliability without requiring excessive safety margins that would limit flight operations.
3Measurement precision
If multiple vibration sensors are distributed throughout the aerodyne, then the measurement precision and detection accuracy improve, but the device complexity and cost increase
Solution Approach 1:
The patent divides the detection system into multiple vibration sensors positioned at specific locations on the rotor hub or aerodyne structure. This segmentation allows the system to capture different vibration modes and frequencies, improving measurement precision and detection accuracy through spatial distribution of measurement points.
Solution Approach 2:
The vibration sensors serve multiple functions: detecting vortex ring state, characterizing vibration patterns, and providing diagnostic information about rotor system health. This multi-functionality justifies the added complexity by providing comprehensive monitoring capabilities from a single sensor type.
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 solution enables accurate and effective detection of the vortex ring state, providing a sufficient margin for pilots to take corrective actions, reducing the risk of accidents by directly measuring vibrations caused by vortex rings, independent of airspeed uncertainties and flight point, and minimizing false alarms through multiple analysis methods.
Implementation Method 1
a set of vibration sensors distributed in or on the rotary wing aerodyne and configured to detect at different points of the rotary wing aerodyne vibrations at least along the longitudinal and vertical axes
Implementation Method 2
process the measurement data received so as to calculate in real time the vibration spectrum of the rotary wing aerodyne along at least one of the longitudinal and vertical axes
Implementation Method 3
the rotary wing aerodyne may enter its own rotor wake, leading to re-ingestion of air streams at the tip of the rotor disc. The vortices thus created lead to an increase in vibrations
Data Source
AI summary
A device for detecting the approach of a vortex ring state for a rotary wing aerodyne, the detection device including a set of vibration sensors configured to be distributed in or on the aerodyne, and a data processing unit configured to receive in real time measurement data from the sensors, process the data in order to calculate in real time the vibration spectrum of the aerodyne, detect in real time, by vibration analysis, the approach of a vortex ring state as a function of the calculated vibration spectrum, and issue an alarm in the event of detection of the approach of a vortex ring state.