Blade Angle Feedback Markers for Edge-Effect Signal Accuracy
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Solution Overview
Problem
Existing blade angle feedback systems in aircraft propellers suffer from reading errors due to the 'edge-effect' and marker geometry, which affects sensor signal strength and accuracy.
Innovation Solution
Implementing high magnetic permeability markers on the feedback device, specifically angled markers with a material like Mu-metal, to amplify sensor signals and maintain consistent magnetic flux, reducing edge-related errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If markers are positioned parallel to the longitudinal axis, then the feedback system can measure blade angle, but edge-effect errors increase reading error as the sensor approaches the edges
Solution Approach 1:
The patent positions markers at an angle relative to the longitudinal axis rather than parallel to it. This asymmetric arrangement ensures that as the feedback device moves axially, the sensor consistently detects markers at optimal positions, eliminating the edge-effect errors that occur with parallel marker placement where sensor proximity to device edges causes reading errors.
2Reliability
If markers are positioned at an angle relative to the longitudinal axis, then edge-effect errors are reduced, but the sensor signal strength decreases
Solution Approach 1:
The patent changes the magnetic permeability parameter of the marker material by applying a coating or plating layer with higher magnetic permeability than the base marker material. This parameter change amplifies the magnetic signal detected by the sensor, compensating for the reduced signal strength that would otherwise result from the angled marker positioning.
Solution Approach 2:
The patent creates a composite marker structure consisting of a base material (such as steel) and a coating or plating layer with different magnetic properties (higher magnetic permeability). This composite construction combines the structural integrity of the base material with the enhanced magnetic signal characteristics of the coating layer, solving the signal strength issue while maintaining the beneficial angled positioning.
3Use of energy by moving object
If high magnetic permeability material is applied to markers, then sensor signal amplitude is amplified, but manufacturing complexity increases
Solution Approach 1:
The patent separates the structural function of the marker (provided by the base material) from the signal-generation function (provided by the high magnetic permeability coating). This extraction allows the marker to be manufactured using standard processes for the base material, with the specialized magnetic coating applied as a separate, relatively simple finishing step, thereby reducing overall manufacturing complexity compared to creating entirely custom high-permeability marker components.
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
Enhances signal detection accuracy and reduces reading errors, ensuring precise blade angle measurements in propeller systems.
Implementation Method 1
the at least one position marker comprising a second material having a second magnetic permeability greater than the first magnetic permeability
Data Source
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AI summary
A blade angle feedback system (200) for an aircraft-bladed rotor (130) rotatable about a longitudinal axis (A) and having an adjustable blade pitch angle is provided. A feedback device (204) is coupled to rotate with the rotor (130) and to move along the axis (A) with adjustment of the blade angle. At least one position marker (420) is affixed to a core of the feedback device (204) and extends along a direction angled relative to the axis (A). The core is made of a first material (504) having a first magnetic permeability and the position marker (420) comprises a second material (502) having a second magnetic permeability greater than the first magnetic permeability. A sensor (212) is positioned adjacent the feedback device (204) and produces, as the feedback device (204) rotates about the axis (A), a sensor signal in response to detecting passage of the position marker (420). A control unit (220) generates a feedback signal indicative of the blade angle in response to the sensor signal.