Aircraft Feedback Device Axial Position Determination
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Solution Overview
Problem
Existing feedback systems for featherable aircraft propellers face limitations in precision due to inaccurate determination of the axial position of feedback devices, which affects the measurement of propeller blade pitch and rotational velocity.
Innovation Solution
A method and system that determine the axial position of feedback devices by generating signal pulses with varying voltage amplitudes based on detectable features with varying magnetic permeability or geometry, allowing for precise calculation of the axial position using voltage ratios and look-up tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensors are used to measure rotation via readable markers, then rotational velocity can be measured, but axial position determination is inaccurate limiting feedback precision
Solution Approach 1:
The feedback device is segmented into multiple features: varying detectable features with different magnetic permeability or geometry for axial position detection, and reference features for rotational position detection. This segmentation allows independent optimization of axial and rotational measurement functions.
Solution Approach 2:
A sensor serves as an intermediary that detects both varying detectable features and reference features on the feedback device. The sensor translates physical features into electrical signals (voltage amplitudes) that can be processed to determine both axial and rotational positions.
2Measurement precision
If varying detectable features with different magnetic permeability are used, then axial position accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
Different regions of the feedback device features have different magnetic permeability or geometric properties. The varying detectable features incorporate local variations in material composition or geometry that create distinct voltage amplitude signatures for axial position detection.
Solution Approach 2:
The magnetic permeability or geometric parameters of the detectable features are intentionally varied to create distinguishable voltage amplitude responses. This allows axial position determination through voltage ratio analysis without requiring complex mechanical structures.
3Measurement precision
If reference features with constant voltage amplitude are used, then rotational velocity measurement is enabled, but distinguishing from varying features becomes challenging
Solution Approach 1:
Instead of making the varying features have constant amplitude and reference features have varying amplitude, the invention inverts this approach: reference features produce constant voltage amplitude signals for rotational detection, while varying detectable features produce amplitude-modulated signals for axial position detection.
Solution Approach 2:
The reference features are configured to generate periodic voltage signals with constant amplitude as the feedback device rotates, enabling rotational velocity measurement through frequency analysis while the varying features create amplitude-modulated periodic signals for axial position detection.
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 enhances the accuracy of feedback systems by reliably determining the axial position of feedback devices, thereby improving the precision of propeller blade angle control and rotational velocity measurement.
Implementation Method 1
the first signal pulse is generated by the at least one varying detectable feature comprising at least one position marker having varying magnetic permeability
Data Source
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AI summary
A sensor signal comprising a first signal pulse having a first voltage amplitude (Vpk-pk1) and a second signal pulse having a second voltage amplitude (Vpk-pk2) greater than or substantially equal to the first voltage amplitude (Vpk-pk1) is obtained from a sensor (212) positioned adjacent a feedback device (204) coupled to rotate with an aircraft-bladed rotor (130) about a longitudinal axis (A) and to move along the axis (A) with adjustment of the rotor's blade pitch angle. The feedback device (204) comprises a reference feature (5022) configured to generate the second signal pulse and varying detectable feature(s) (5021) configured to generate the first signal pulse and to cause a change in the first voltage amplitude (Vpk-pk1) as a function of an axial position of the feedback device (204) along the axis (A). A voltage ratio is determined based on the first voltage amplitude (Vpk-pk1) and the second voltage amplitude (Vpk-pk2), and the axial position of the feedback device (204) is determined from the voltage ratio.