Blade Angle Feedback System with Extended Position Markers
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Solution Overview
Problem
Existing blade angle feedback systems for aircraft propeller systems are vulnerable to 'edge-effects' that increase reading errors as sensors approach the edges of the feedback device, leading to inaccurate measurement of propeller blade pitch.
Innovation Solution
The solution involves extending position markers beyond the edges of the feedback device to increase magnetic flux density, allowing sensors to detect changes in magnetic flux more accurately, even when the feedback device is displaced along its longitudinal axis, thereby mitigating edge-related effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor is positioned close to the feedback device to improve measurement sensitivity, then measurement precision improves, but edge-effect errors increase significantly
Solution Approach 1:
The position markers are extended in the axial direction (longitudinal axis dimension) beyond the radial edges of the feedback device. This dimensional extension creates marker portions that rotate beyond the sensor's radial detection zone, allowing the sensor to detect markers even when the feedback device is displaced axially, thereby eliminating edge-effect errors while maintaining close positioning for high sensitivity
2Speed
If the feedback device is allowed to rotate freely with the propeller shaft, then rotational velocity measurement is accurate, but axial displacement causes magnetic flux path disruption
Solution Approach 1:
The position markers are pre-configured to extend axially beyond the feedback device edges before operation begins. This preliminary configuration ensures that regardless of subsequent axial displacement during operation, the markers will always have portions that rotate into the sensor's detection zone, maintaining continuous and accurate magnetic flux detection throughout the operational range
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 configuration enhances the accuracy of blade angle measurement by maintaining a continuous magnetic flux path and increasing sensor signal strength, reducing edge-related errors and ensuring precise detection of position markers.
Implementation Method 1
the at least one sensor is configured to detect, as the feedback device rotates about the longitudinal axis, a change in magnetic flux caused by passage of the at least one position marker in a sensing zone of the at least one sensor
Data Source
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AI summary
A blade angle feedback assembly (200) for an aircraft-bladed rotor (130) and an aircraft-bladed rotor system are provided. The rotor (130) is rotatable about a longitudinal axis (A) and has an adjustable blade pitch angle. A feedback device (204) is coupled to rotate with the rotor (130), the feedback device (204) having a root surface (304) having an edge (3021, 3022). At least one position marker (202) extends from the root surface (304) and extends laterally beyond the edge (3021, 3022). At least one sensor (212) is mounted adjacent the feedback device (204) and configured to detect a passage of the at least one position marker (202) as the feedback device (204) rotates about the longitudinal axis (A).