Test Fixture for AOA Sensor Vane Calibration
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Solution Overview
Problem
Existing calibration test devices for angle of attack (AOA) sensor vanes on aircraft are heavy, prone to instability, and lose calibration over time, making them unreliable for consistent and repeatable testing.
Innovation Solution
A lightweight test fixture with a transiently secured outer disc and a rotatably engaged inner disc, featuring a spur gear and ring gear mechanism, allows for precise rotation of the sensor vane for calibration accuracy testing, using a manual adjustment knob and actuator lever for reliable engagement and disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heavy metal parts are used in the test device, then the device has sufficient structural strength, but the device becomes difficult to manipulate and prone to loss of calibration
Solution Approach 1:
The patent changes the material parameter from heavy metal to lightweight material, fundamentally altering the weight characteristic while maintaining structural adequacy through design optimization rather than material mass
Solution Approach 2:
The test device is divided into modular components including an index plunger unit, support structure, and calibration mechanisms that can be independently positioned and adjusted, improving ease of manipulation while maintaining overall structural strength
2Ease of operation
If metal rods and springs are used to support the index plunger unit, then the device provides initial mechanical support, but the rods become loose or unstable after several engagements
Solution Approach 1:
The patent replaces the mechanical rod-and-spring support system with a rigid structure that incorporates adjustable positioning mechanisms and locking features, eliminating the progressive loosening problem inherent in elastic spring-based support systems
Solution Approach 2:
The device incorporates adjustable and repositionable features that allow the support structure to be dynamically reset to precise positions after each engagement, preventing the cumulative drift that occurs with fixed mechanical spring systems
3Stability of the object's composition
If a fixed structural design is used, then the device maintains consistent geometry, but the device loses calibration accuracy over time
Solution Approach 1:
The patent incorporates adjustable positioning mechanisms and repositionable components that allow the geometric relationships to be dynamically reset to reference positions, combining the stability of fixed geometry with the flexibility to correct calibration drift
Solution Approach 2:
The device includes pre-established reference positions and alignment features that enable rapid recalibration to known accurate positions before each testing session, preventing accumulation of calibration errors
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 solution provides a stable, lightweight, and reliable method for maintaining calibration accuracy of AOA sensor vanes, ensuring consistent and repeatable testing results while minimizing the risk of device instability.
Implementation Method 1
The inner disc includes an adjustment feature including a spur gear that reacts with the ring gear for rotation of the inner disc
Data Source
AI summary
A test fixture for determining calibration accuracy of an aircraft angle of attack sensor vane includes an outer disc, configured to be transiently fixed to an aircraft exterior portion surrounding the sensor vane, and an inner disc that includes a spring-loaded plunger configured to physically engage the sensor vane during tests. The inner disc is rotatable relative to the outer disc to accommodate rotation of the sensor vane when engaged with the inner disc. The outer disc includes a ring gear fixed thereto; the inner disc includes a manually operated knob containing a spur gear that reacts with the ring gear to rotate the inner disc when the knob is rotated. The outer disc is a clamshell structure formed of an upper annular disc and a lower annular disc rigidly secured together, and the inner disc is rotatably retained between the upper and lower annular discs.