Aircraft Angle Measurement Probe Using Optical Encoders
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Solution Overview
Problem
Existing angle measurement probes on aircraft are bulky, heavy, sensitive to electromagnetic threats, and require multiple power supply voltages, making them costly and difficult to integrate, especially in limited spaces, while also being sensitive to icing conditions.
Innovation Solution
A novel angle measurement probe with a rotating fin using dual optical encoders, each with two disks and circular tracks, providing redundant data processing for robustness and reduced alignment requirements, and incorporating temperature sensors and heating mechanisms for de-icing, allowing operation in single- or double-accuracy modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rotating electrical machines or pressure difference devices are used to measure angle of attack and side slip angle, then measurement capability is achieved, but the probe becomes heavy, bulky, and sensitive to electromagnetic threats
Solution Approach 1:
The patent replaces traditional rotating electrical machines and pressure difference devices with optical encoders that use light-based measurement. The optical encoder system uses a transparent or translucent vane that deflects air flow, and optical sensors detect the deflection angle through refractive index changes, eliminating heavy mechanical components and their associated electromagnetic sensitivity.
Solution Approach 2:
The invention changes the measurement parameter from electrical signals or pressure differences to optical properties (refractive index). By detecting changes in the refractive index of air caused by vane deflection, the system achieves angle measurement without electromagnetic components, thereby reducing weight and electromagnetic vulnerability.
2Measurement precision
If traditional sensors with high accuracy are employed, then measurement precision is improved, but cost and device complexity increase
Solution Approach 1:
The patent replaces complex rotating electrical machines with a simpler optical encoder system. The optical encoder uses basic optical components (light source, detector, and refraction-based angle sensing) that are inherently simpler than electromagnetic machines, reducing both complexity and cost while maintaining measurement precision through optical refraction principles.
3Reliability
If rotating fins or multifunction devices are used for angle measurement, then measurement function is provided, but the probe volume and integration difficulty increase
Solution Approach 1:
The patent integrates the optical encoder components within a compact housing that contains the vane, optical sensors, and processing electronics in a nested arrangement. The optical path is folded within the housing volume, allowing the measurement function to be achieved in a much smaller probe volume compared to traditional rotating fin systems.
4Reliability
If traditional probes are used in icing conditions, then measurement capability is maintained, but de-icing requirements increase weight and power consumption
Solution Approach 1:
The patent replaces electromagnetic sensors with optical encoders that have no electromagnetic components to fail or require heating. The optical system is inherently more resistant to icing effects, and the vane design allows for passive de-icing or minimal heating requirements, significantly reducing power consumption compared to traditional heated electromagnetic sensors.
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 probe reduces mechanical loads and length by 40%, is less sensitive to electromagnetic interference, and maintains accuracy in harsh conditions, enabling efficient and reliable angle of attack and side slip angle measurements with reduced weight and complexity.
Implementation Method 1
at least one first optical encoder and one second optical encoder, each comprising at least one disk, each disk being fixed at right angles to the central axis and being provided with at least two circular tracks, each track being provided with alternate opaque zones and transparent slots
Implementation Method 2
incorporating temperature sensors and heating mechanisms for de-icing
Data Source
Figure 1A~2
Figure 3~4B
Figure 4C
AI summary
The invention relates to an angle measurement probe on board an aircraft, comprising: - a fin (25), which can move in rotation about an axis (24), - at least one first optical encoder (26) and one second optical encoder (27), each comprising at least one disk (80-83), each disk being fixed at right angles to the central axis (24) and being provided with at least two circular tracks (87), each track being provided with transparent slots alternating with opaque zones, each disk (80, 81, 82, 83) comprising at least two concentric tracks, each comprising successive slots (851, 852, 861, 862), the slots of each track being offset relative to the slots of each other track, - means (30, 31) for processing the output signal from each encoder.