Rotor Pitch Feedback Assembly with Edge-Effect Error Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing feedback devices in aircraft propeller systems are vulnerable to an 'edge-effect' that leads to increased reading errors when sensors approach the edges, affecting the accuracy of propeller blade pitch angle measurement.
Innovation Solution
The feedback device incorporates a plurality of position markers with varying lengths and geometries, including chamfered ends, to improve detection precision and reduce edge-effect errors, using sensors to generate feedback signals for accurate blade pitch control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional feedback devices with uniform position markers are used, then the device structure is simple, but reading error increases due to edge-effect when sensor approaches edges
Solution Approach 1:
The patent applies local quality by varying the geometry of position markers specifically at edge locations. Position markers at the periphery of the feedback device have different geometric characteristics (such as different lengths or shapes) compared to those at central locations. This local modification compensates for the edge-effect without requiring changes to the entire marker array, thus improving reading accuracy while maintaining reasonable device complexity.
Solution Approach 2:
The patent employs asymmetry by introducing position markers with non-uniform geometries at specific locations, particularly at edges. Instead of using identical symmetric markers throughout, the edge markers are designed with asymmetric or differentiated characteristics that compensate for the sensor's edge-effect, thereby improving measurement precision in critical regions.
2Measurement precision
If position markers with varying lengths and geometries are implemented, then edge-effect errors are reduced, but manufacturing complexity increases
Solution Approach 1:
By applying local quality, only specific position markers at edge locations require specialized geometries, while central markers can remain uniform. This localized approach to manufacturing complexity reduces the overall difficulty of fabrication compared to requiring all markers to have complex varying geometries, while still achieving the goal of reduced edge-effect errors.
3Measurement precision
If chamfered ends are added to position markers, then detection precision is improved, but device complexity increases
Solution Approach 1:
The chamfered ends are applied locally to position markers rather than uniformly to all markers. This localized application of chamfered features provides enhanced detection precision where needed (at edge locations subject to edge-effect) while minimizing the overall increase in device complexity by not requiring chamfered features on every marker.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The present disclosure provides methods and systems for controlling a pitch for an aircraft-bladed rotor (130). A plurality of sensor signals are obtained from at least one sensor (212) positioned proximate to a feedback device (300), the feedback device (300) coupled to rotate with the rotor (130) about a longitudinal axis (A) and to move along the longitudinal axis (A) with adjustment of a blade pitch angle of the rotor (130), the sensor signals produced responsive to detecting passage of a plurality of position markers (320) of the feedback device (300), the plurality of position markers (320) spaced circumferentially around the feedback device (300) and having lengths along the longitudinal axis (A) which vary monotonically and incrementally along at least part of the circumference of the feedback device (300). The plurality of sensor signals are processed to identify passage of the plurality of position markers (320). A feedback signal indicative of the blade pitch angle is generated based on the processed sensor signals.