Differential Pressure AOA Sensor Using Conductive Foam
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Solution Overview
Problem
Existing angle of attack (AOA) sensors on aircraft face reliability issues due to exposure to harsh environmental conditions and human errors, with vane-based sensors being complex and inaccurate, and pressure-based sensors ineffective at high angles and in sandy environments.
Innovation Solution
A pressure-based, fuselage-mounted differential pressure AOA sensor system using pitot tubes and conductive foam pressure sensors, with a microcontroller to generate accurate AOA measurements by comparing ram air pressure with calibrated values, eliminating the need for complex maintenance and reducing inertial effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vane-based sensors are used for AOA measurement, then the sensor can detect angle of attack, but the device complexity increases and measurement precision decreases
Solution Approach 1:
The patent replaces the mechanical vane-based sensing system with a pressure-based sensing system. Instead of using physical vanes that rotate mechanically to indicate AOA, the invention uses pressure sensors to measure differential air pressures at multiple ports, which are then processed by a microcontroller to determine AOA. This substitution eliminates mechanical complexity while improving measurement precision through electronic sensing and computational processing.
Solution Approach 2:
The patent divides the sensing system into multiple independent pressure sensors positioned at different locations and orientations on the fuselage. Each sensor measures pressure at its specific location, and the microcontroller integrates these multiple measurements to calculate the overall AOA. This segmentation allows the system to achieve accurate AOA measurement without requiring a single complex mechanical sensor.
2Device complexity
If pressure-based sensors are used for AOA measurement, then the device complexity is reduced, but reliability worsens in high angles and sandy environments
Solution Approach 1:
The patent employs multiple pressure sensors positioned at different locations and orientations on the fuselage. This segmentation provides redundancy, as the system can continue to function and provide accurate AOA measurements even if some individual sensors are blocked or fail due to sandy environments or high-angle flight conditions.
Solution Approach 2:
The patent changes the operational parameters of the pressure sensors by positioning them at various angles and locations on the fuselage. This allows the system to maintain reliable measurements across a wide range of flight conditions, including high angles of attack and sandy environments, by selecting or weighting sensor readings based on current flight parameters.
3Reliability
If multiple pressure sensors are used to improve reliability, then the system maintains accuracy in blocked ports, but manufacturing cost increases
Solution Approach 1:
The patent uses multiple relatively simple pressure sensors positioned at different locations on the fuselage. While this increases component count, each individual sensor remains a simple, inexpensive pressure-sensing element. The redundancy provided by multiple sensors improves reliability and tolerance to blocked ports while keeping individual component costs low.
Solution Approach 2:
The patent uses multiple copies of the same pressure sensor design in different positions and orientations. This allows the system to achieve improved reliability through redundancy while maintaining ease of manufacture, as the same standardized sensor component can be replicated and installed in various locations without requiring complex or expensive custom components.
4Ease of operation
If fuselage-mounted sensors are used instead of wing-mounted sensors, then ease of operation improves, but measurement precision may be affected by fuselage interference
Solution Approach 1:
The patent positions multiple pressure sensors at different locations on the fuselage, including areas less susceptible to flow interference. By segmenting the sensing locations and using computational processing to integrate the measurements, the system maintains measurement precision while achieving the ease of operation benefits from fuselage mounting.
Solution Approach 2:
The patent replaces the need for precise mechanical positioning and alignment (required for accurate measurements from wing-mounted sensors) with a distributed pressure sensing network on the fuselage. The microcontroller processes the pressure data from multiple sensors to compensate for fuselage interference, maintaining measurement accuracy while simplifying installation and maintenance operations.
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
The system provides accurate AOA measurements during various aircraft movements, is cost-effective, and maintains reliability even if some ports are blocked, without moving parts, thus improving flight safety and reducing maintenance complexity.
Implementation Method 1
A pressure-based, fuselage-mounted differential pressure AOA sensor system using pitot tubes and conductive foam pressure sensors
Implementation Method 2
conductive foam pressure sensors, wherein each of the pressure sensors generates a respective ram pressure measurement
Data Source
AI summary
An angle of attack (AOA) sensor system is disclosed. The system comprises a plurality of pitot tube ports in a housing. The pitot tube ports include a set of positive angle pitot ports, a set of negative angle pitot ports, and a central pitot port. The central pitot port is aligned with a central chord line of a wing of the aircraft. A plurality of pitot tubes communicate with the plurality of pitot tube ports (at a first end), and with a plurality of pressure sensors (at a second end). A microcontroller is configured to generate a respective current AOA value for each pressure sensor based on a respective ram pressure measurement generated by each of the pressure sensors, and generate an AOA measurement of the aircraft by comparing each respective current AOA value to respective calibrated AOA values stored in a memory.