Autonomous Systems Imaging of Aerospace Structures

Lead Research Organisation: CRANFIELD UNIVERSITY
Department Name: Sch of Aerospace, Transport & Manufact

Abstract

The ultimate objective of the research is to deliver an automated innovative damage evaluation tool capable to detect and characterize damage on either metallic or composite aerospace materials and structures by novel optimal fusion of non-invasive imaging technologies. Overall, the PhD student will develop both software and hardware tools combining the advantages of the applied novel imaging technologies in order to assess type, size and depth of defects in both qualitative and quantitative terms. This will be achieved by both modelling and experimental work completed in the framework of the PhD research.

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509450/1 30/09/2016 29/09/2021
2199214 Studentship EP/N509450/1 22/01/2018 21/07/2021
 
Description The aim of this project is to create an unmanned aerial vehicle to perform an inspection of aerospace structures, with as much information as possible, however the novelty focus is on the subsurface composite damages using the active thermographic method.
To date this has consisted of;
• Building a UAV (unmanned aerial vehicle
1. Building the Hardware
2. Programming the UAV to fly (autonomous flight being trialled using a VICON system)
3. Using software development kits to develop relevant functions to the project (still under development)
• NDT (Non-destructive testing)
1. Literature review on Non-destructive testing (thermographic inspection)
2. Performing NDT active thermography testing (many test have been achieved using a sensor and an excitation source)
3. Post-processing of thermal data. i.e Signal processing (the results interpreted to understand the extent of the damage on composite structures)
• UAV and NDT integration
1. Using an embedded system onboard a UAV to allow the UAV to perform tasks [communication, data transfer, and onboard processing was some knowledge necessary for this]
2. Sensors where mounted. E.g guidance system (stereovision cameras, ultrasound), thermal camera controlled by an onboard computer and 2 other optical cameras, one that communicates with the UAV itself and one that communicates with the onboard computer.
As of now the UAV can inspect structures using both a thermal and RGB camera whilst feeding the information back to a ground station wirelessly. The UAV can avoid structures using the onboard object detection which includes stereovision cameras and ultrasound sensors.
[Images from the guidance system will be extracted in the future to allow depth perception of the subject of interest, which is important for figuring out the depth of a damage]
The UAV can identify objects (in this case abnormalities of the aircraft) onboard using some deep learning methods such as crack detection and machine learning (this is still a manual process, but it should be automatic soon. it can capture and store these images. The image is fed to the ground station (another computer), post processing can then begin. The size of the damage can be found using the python language.
Trying to install an excitation source onboard a UAV is proving to be near impossible due to the energy needed to power the system. The excitation source is required to stimulate the material properties while the thermal camera observes and captures a series of images, the result will provide subsurface damage detection if present, which is not visible optically or with a thermal camera without some form of material stimulation.
The aim is to mount the excitation source onto a UAV however it will need to be tethered so it can get the power it requires.
Exploitation Route Others could use the all in one drone inspection method to access the health of structures. Using the several techniques mentioned and implemented. The UAV can inspect a wide range of subjects and be used in many different application, particular useful for hard-to-reach areas. The active thermography inspection techniques remotely remains a challenge as its depended on a power sources which is remote and can provide enough power, the technology is not quite available, however the outcome of this project can give people an understand of a partly remote active thermographic method including the image processing of the thermal data.
Sectors Aerospace

Defence and Marine

Construction

Digital/Communication/Information Technologies (including Software)

Electronics

Manufacturing

including Industrial Biotechology

Transport
 
Description The findings have been used by a company known as OASIS LTD. The company uses Drones to inspect high value assets in the energy, maritime and now the aerospace sector due to the student's research. The findings have given people an understanding of aircraft damages, primarily in composites. Also using a drone to inspect an aircraft structure safely and understand the procedure to locate damage, as there are many different categories of damage and the damage will be different on the different materials. Using algorithms to find abnormalities on aircraft has been implemented by the above-mentioned company. The company also uses passive thermography to locate defects and is looking to implement active thermography in the future if the students research project of implementing an active thermographic drone is successful. The student's validation of the effectiveness of the uncooled microbolometer sensor was useful for the company, which allowed them to purchase a cheaper and smaller sensor. All in all if the becomes operational in the Aerospace sector like it is in inspection wind turbines, then it could benefit airliners by reducing maintenance cost and time whilst ensuring the safeness of the aircraft.
First Year Of Impact 2019
Sector Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Energy,Transport