Rotorcraft Blade Angular Position Measurement via Checkered Pattern Imaging
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Solution Overview
Problem
Existing measuring devices for determining the angular positions of rotorcraft blade elements are complex, unreliable, and require modifications to the structural design, as they often rely on optical sensors and light sources that are difficult to integrate and maintain, especially in rotary axes, limiting their ability to measure complete revolutions accurately.
Innovation Solution
A measuring device featuring a checkered pattern with different luminance factors attached to the blade element, a camera secured to the hub, and a synchronization member to record images with time parameters, allowing for automatic determination of angular positions along multiple axes of rotation without altering the structural design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors and light sources are used to measure angular positions, then measurement capability is provided, but device complexity and structural modification requirements increase
Solution Approach 1:
The patent uses a checkered pattern (a visual copy or representation) attached to the blade element instead of complex optical sensors. The camera captures images of this pattern, and software processes the visual information to determine angular positions, replacing physical sensing hardware with a visual documentation approach.
Solution Approach 2:
The patent replaces the mechanical/optical sensor system with a photographic imaging system. Instead of using light sources and detectors mounted on rotating components, the solution uses a stationary camera to take pictures of a checkered pattern, substituting mechanical sensing with optical documentation and computational analysis.
2Measurement precision
If optical sensors are integrated on rotary axes, then angular position measurement is enabled, but reliability decreases due to wear of electrical contacts
Solution Approach 1:
The patent extracts the measurement function from the rotating blade element and places it on the stationary hub. The camera and all electronic components are mounted on the non-rotating hub, while only a simple checkered pattern is attached to the rotating blade. This separation eliminates wear-prone electrical contacts on rotary axes.
Solution Approach 2:
The measurement information is obtained through visual copying via photography rather than electrical sensing. The checkered pattern serves as a visual marker that can be photographed without requiring electrical connections, using light reflection instead of electrical signals.
3Measurement precision
If a camera is placed on the fuselage with a strobe light, then angular positions can be captured, but device complexity and implementation difficulty increase
Solution Approach 1:
The hub serves multiple functions: it supports the rotor blades and simultaneously mounts the camera and synchronization components. This multi-functional use of the hub structure reduces overall system complexity by consolidating measurement equipment on an existing structural component rather than requiring separate mounting systems.
Solution Approach 2:
The patent uses standard photographic imaging without specialized strobe lights or complex illumination systems. The checkered pattern provides sufficient contrast under normal lighting conditions, allowing the use of conventional cameras and eliminating the need for additional lighting equipment.
4Measurement precision
If light sources are integrated on blade elements, then measurement capability is provided, but manufacturing complexity and electrical routing requirements increase
Solution Approach 1:
Instead of integrating light sources into the blade structure, the patent uses a checkered pattern that reflects ambient light. This visual marker can be attached to the blade surface without modifying the internal structure or requiring electrical connections, maintaining manufacturing simplicity.
Solution Approach 2:
Rather than placing active components (light sources) on the blade and passive detectors on the hub, the patent inverts the arrangement: the passive checkered pattern is on the blade while the active camera is on the stationary hub. This inversion eliminates the need for electrical routing on the rotating blade.
Data Source
AI summary
A measurement device for measuring the angular positions of a blade element of a rotorcraft, the blade element being arranged to be movable relative to a hub of a rotor in pivoting about at least one pivot axis. The invention also relates to a rotorcraft fitted with such a measurement device and to a corresponding measurement method.