During the project, the consortium established the requirements and specifications, reviewed the typical defects in aircraft structures and NDT approaches for their detection, the applications and automation challenges in using PA and IRT for aircraft maintenance, the use of lasers for repair, and a state of the art in wall-climbing robotics.
An outline of specifications and conceptual design of the Vortex Robot Platform (VRP) was performed, aiming to enable successful attachment and motion on the target surfaces via the combination of different actuation methods while carrying the required modules.
Novel IR thermography approach was developed based on the combination of pulsed phase (PPT) and lock-in (LT) IR thermography techniques, as none of the existing techniques can individually perform online damage assessment on the Vortex robot.
Portable PA hardware suitable for in-service inspection was developed and tested. The PA transducer performance requirements were derived from Finite Element (FE) modelling and following laboratory trials with various calibration samples. Methodology for in-service inspection of aircrafts was proposed with review and performance evaluation of suitable signal processing algorithms.
A prototype for automatic laser-based material cutting/grinding of composites was developed. A prototype of the system for composite material removal based on lightweight green laser was built and successfully evaluated, integrated in a manipulator robot.
In the second period the consortium:
- Designed a Vortex Actuation System (VAS) following extensive experimental study, which led to a novel methodology for achieving the optimal adhesion performance. A Small-Scale Vortex Robot (SSVR) utilising the VAS was designed and manufactured with the following experimental evaluation at surfaces of different inclinations.
- Completed the development and evaluation of functionality of the Near IR thermography for assessing damages in transparent and semi-transparent aircraft parts, such as delamination from impacts on composite fuselage.
- Developed a high-resolution (high-frequency and software enhanced) PA imaging technology for in-service inspection beyond the current state-of-the-art: a custom rubber wedge for a high frequency PA transducer, a mist based couplant sub-system, positioning fixture, an ad hoc subsystem for integration in the VR and of a visualization software allowing for 2D and 3D representation of defects in the material.
- Completed development and validated algorithms for defects detection, characterisation and patch geometry calculation integrated into the Graphical User Interface realising the complete workflow.
- Investigated the effectiveness of stepped repair to damaged fibre reinforced composite materials by using FE models. A parametric study was conducted in order to evaluate the influence of the scarf ratio on the integrity of the repaired laminate and the restoration of stiffness. The modules for automated repair of aircraft structures, including material removal and placement of the relevant patch, were designed according to the requirements of the robotic platform and manufactured.
In the last period the consortium:
- Fully integrated the PA and IRT modules on the Vortex robotic platforms. The performance of the robotic inspectors has been tested on a demonstrator composite panel, representative of an aerospace structure, manufactured with stiffeners, copper mesh and painted.
- The influence of repair patch geometry has been assessed using refined FE models.
- The laser-repair module has been fully integrated on a manipulator robotic platform, with an advanced control software. Evaluation of the performance has been done on the demonstrator panel.
- The patch-placer module has been tested on the demonstrator panel, jointly with a porosity assessment of the cured material based on a specialized ultrasonic inspection module.
- The overall solution has been tested on the demonstrator panel, in an integrated way.
- Exploitation of the Vortex Robotic inspectors is being pursued in a sensor-agnostic way.
- Dissemination activities have been carried out about all modules and subsystem developed, and totally 27 scientific publications have been done.
- Results of the project have been disseminated to the general public and industrial partners in a series of ad-hoc events by Cranfield and all the partners. The total outreach is in order of thousands of people that have heard of the CompInnova project.
