Doppler LIDAR Gust Alleviation for Lift-Stable Turbulence Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current systems for reducing airplane fluctuations during turbulence require high accuracy and reliability in two-dimensional airflow vectors, which is challenging due to the need for multiple optical axes and consideration of elastic deformation, leading to conversion errors and practical limitations in automatic control.
Innovation Solution
A gust alleviation system using a Doppler LIDAR that measures remote wind speed and calculates an angle of attack with a low lift-curve slope to control the airplane's lift without relying on prior airflow vector information, employing a control calculation unit to adjust the control surface and reduce fluctuations by managing lift changes caused by gusts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two or more sets of Doppler LIDAR are used to obtain vertical airflow vector, then the accuracy of airflow measurement is improved, but the device complexity and cost increase
Solution Approach 1:
The invention divides the measurement task into two independent parts: (1) a single Doppler LIDAR measures the longitudinal wind speed component along the flight direction, and (2) the vertical wind speed component is calculated indirectly through geometric conversion using the known relationship between the measured longitudinal component and the total wind vector. This segmentation allows accurate airflow vector obtention without requiring multiple Doppler LIDAR sets.
Solution Approach 2:
The invention extracts only the necessary measurement component (longitudinal wind speed along flight direction) that can be obtained by a single Doppler LIDAR, and derives the remaining component (vertical wind speed) through mathematical calculation based on geometric relationships, rather than directly measuring all components simultaneously with multiple sensors.
2Productivity
If automatic control of control surface is implemented using airflow vector, then the productivity of turbulence mitigation is improved, but the reliability requirement becomes extremely high and elastic deformation must be considered
Solution Approach 1:
The invention performs preliminary measurement of the longitudinal wind speed component before turbulence impact, and uses geometric conversion to predict the vertical wind speed component in advance. This preliminary action provides sufficient lead time for automatic control system to adjust the control surface, reducing the stringency of real-time response requirements and allowing more relaxed reliability specifications.
3Measurement precision
If geometric conversion of observed values is used to obtain vertical airflow vector, then the measurement capability is improved, but conversion errors are introduced
Solution Approach 1:
The invention changes the measurement parameter from directly measuring the vertical wind speed component (which would require complex multi-axis sensor arrangements) to measuring the longitudinal wind speed component along the flight direction, which can be accurately obtained by a single Doppler LIDAR. The vertical component is then derived through parameter transformation based on geometric relationships, maintaining measurement accuracy while simplifying the measurement system.
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 approach effectively reduces airplane fluctuations during turbulence without the need for two-dimensional airflow vectors, improving safety and comfort by minimizing lift changes and avoiding elastic deformation, while also reducing fuel consumption and operational complexity.
Implementation Method 1
measures a remote wind speed in a radiation axis direction of the emitted electromagnetic waves based on a Doppler shift amount of a frequency between the emitted electromagnetic waves and the scattered electromagnetic waves
Data Source
AI summary
[Object] To provide a technique for reducing the fluctuation of an airplane when an airplane enters turbulence without using prior information of two-dimensional or more airflow vectors.[Solving Means] A system includes: a measurement unit 10 that emits electromagnetic waves toward a planned flight direction of the airplane, receives scattered waves of the emitted electromagnetic waves in atmosphere, and measures a remote wind speed in a radiation axis direction of the emitted electromagnetic waves based on a Doppler shift amount of a frequency between the emitted electromagnetic waves and the scattered electromagnetic waves; a spoiler 221 that controls a lift of the airplane; and a control calculation unit 30 that calculates an angle of attack with less lift inclination and calculates an angle of the spoiler 221 that controls the lift so that the lift does not change when it is determined that the airplane will receive a gust, based on a measurement result of the measurement unit 10.