Blade Angle Feedback Assembly with Offset Sensors
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Solution Overview
Problem
Existing blade angle feedback systems in featherable aircraft propeller systems are vulnerable to 'edge-effect' errors, leading to increased reading errors as sensors approach the edges of the feedback device.
Innovation Solution
The implementation of a blade angle feedback assembly with multiple axially offset sensors, where one sensor is designated as primary based on minimized reading error, and the reading is averaged with another sensor at the edge position to mitigate edge-related errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single sensor is used to measure blade angle, then the device complexity is reduced, but measurement precision deteriorates due to edge-effect errors
Solution Approach 1:
The patent divides the sensing function into multiple segments by using several sensors positioned at different axial locations along the feedback device. Each sensor measures blade angle from its specific position, and the measurements are combined to eliminate edge-effect errors. This segmentation allows the system to maintain high measurement precision across the entire blade angle range while managing device complexity through modular sensor placement.
2Measurement precision
If multiple sensors are used to eliminate edge-effect errors, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent merges the measurements from multiple sensors into a single combined blade angle measurement. By mathematically combining the readings from sensors positioned at different axial locations, the system eliminates edge-effect errors while presenting a unified measurement output. This merging approach maintains measurement precision without proportionally increasing the complexity of the overall measurement system.
Solution Approach 2:
The patent introduces an additional spatial dimension by positioning sensors at different axial locations along the feedback device rather than using multiple sensors at the same location. This dimensional approach allows the system to capture blade angle information from multiple perspectives, enabling error elimination through spatial diversity while keeping each individual sensor simple and manageable.
3Adaptability or versatility
If sensors are positioned at the edge of the feedback device, then the sensing range is maximized, but measurement precision deteriorates due to edge-effect errors
Solution Approach 1:
The patent segments the sensing function across multiple axial positions, allowing each sensor to operate within its optimal measurement range while avoiding the problematic edge regions. By distributing sensors along the axial direction, the system maintains comprehensive sensing coverage without any single sensor being subjected to edge-effect errors, thus preserving both sensing range and measurement precision.
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 significantly reduces beta error, ensuring accurate blade angle measurements across the entire range of propeller operation, including primary blade angle and maximum reverse positions.
Implementation Method 1
a sensor can be used to measure the rotation of the feedback device via the markers
Data Source
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AI summary
A blade angle feedback assembly (200) for an aircraft-bladed rotor (130), the rotor (130) rotatable about a longitudinal axis (A) and having an adjustable blade pitch angle, is provided. The assembly (200) comprises a feedback device (204) coupled to rotate with the rotor (130) and to move along the longitudinal axis (A) with adjustment of the blade pitch angle, the feedback device (204) comprising a plurality of position markers (202) circumferentially spaced around the feedback device (204), a plurality of sensors (212, 212A, 212B) positioned adjacent the feedback device (204) and each configured for producing a sensor signal in response to detecting passage of the position markers (202) as the feedback device (204) rotates about the longitudinal axis (A), the sensors (212, 212A, 212B) circumferentially spaced around the feedback device (204) and axially offset along the longitudinal axis (A), and a control unit (220) communicatively coupled to the sensors (212, 212A, 212B) and configured to generate a feedback signal indicative of the blade pitch angle in response to the sensor signals received from the sensors (212, 212A, 212B).