Aircraft Control Surface Free Play Testing Apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for testing free play and backlash in aircraft control surfaces, especially for smaller and medium-sized aircraft, are time-consuming, expensive, and lack accuracy due to the complexity of static testing setups and the inability to accurately measure free play using dynamic testing systems.
Innovation Solution
A testing apparatus and method that includes a support structure with attachment assemblies and an actuator with a rectilinearly moveable shaft to apply loads to the control surface, coupled with a load cell and displacement transducer to generate a load versus displacement curve, allowing for precise determination of free play and backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dynamic free play testing is used with accelerometers and shakers, then vibration frequency correlation can be obtained for larger aircraft, but the method is not applicable to smaller and medium sized aircraft and lacks accuracy for static free play measurement
Solution Approach 1:
The testing system is segmented into separate functional modules: a support structure with attachment assemblies for positioning, an actuator for applying controlled loads, a load cell for force measurement, and a displacement transducer for position measurement. This modular segmentation allows the system to be adapted to different aircraft sizes and control surface configurations while maintaining measurement accuracy.
Solution Approach 2:
The testing apparatus is designed with universal attachment assemblies that can be configured for different aircraft types and control surface geometries. The actuator and sensor system can measure both static free play and dynamic characteristics, making the system versatile across different aircraft categories rather than limited to specific size ranges.
2Measurement precision
If conventional static free play testing is performed with lead baskets and manual loading, then free play can be measured, but the process becomes very time consuming and expensive
Solution Approach 1:
The manual mechanical loading system using lead baskets is replaced with an actuator system that can apply controlled loads automatically. The load cell and displacement transducer provide automated data collection, eliminating the need for manual positioning and measurement recording, thereby significantly reducing testing time and operational costs.
Solution Approach 2:
The actuator system enables continuous loading and data collection throughout the test process, rather than requiring discrete manual loading steps. The system can continuously apply load and record corresponding displacement measurements, allowing for efficient completion of the full load range in a single continuous operation.
3Measurement precision
If static testing is performed with complex loading devices fixed to control surfaces, then free play data can be obtained, but the setup complexity increases and requires system accommodations during each loading step
Solution Approach 1:
The testing device is divided into separate, independently positionable components: attachment assemblies that fix to the aircraft structure, an actuator that applies load, and sensors that measure response. This segmentation reduces the complexity of any single component and simplifies the overall setup process compared to a monolithic loading device.
Solution Approach 2:
The support structure acts as an intermediary between the aircraft structure and the actuator-sensor system. It provides a stable mounting platform that simplifies the attachment process and eliminates the need for complex direct fixation of loading devices to control surfaces, thereby reducing setup complexity while maintaining measurement accuracy.
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 enables efficient and accurate measurement of free play and backlash in aircraft control surfaces, reducing testing time and cost while providing reliable data for ensuring aircraft safety.
Implementation Method 1
a load cell to sense applied loads to the control surface and output a load signal indicative thereof
Implementation Method 2
a displacement transducer to output a deflection measurement signal indicative of the control surface
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Testing apparatus, systems (10) and methods are provided to obtain measurements pertaining to aircraft control surfaces (ACS) mounted to stationary aircraft structures (AAS) for displacements about a hinge axis (HA). A support structure (AAS) and an actuator (18) carried by the support structure may be provided, the support structure including attachment assembles (14a) for positionally fixing the testing apparatus to the stationary aircraft structure (AAS). The actuator (18) carried by the support structure (AAS) includes a rectilinearly moveable actuator shaft (18a) which contacts the aircraft control surface (ACS) when the support structure is positionally mounted to the stationary aircraft structure (AAS). Actuation of the actuator (18) will thereby cause the actuator shaft to apply a load to the moveable aircraft control surface (ACS) to cause deflection thereof about the hinge axis (HA).