Robotic path planning for non-destructive testing of complex shaped surfaces

Abstract

Abstract. The requirement to increase inspection speeds for non-destructive testing (NDT) of composite aerospace parts is common to many manufacturers. The prevalence of complex curved surfaces in the industry provides significant motivation for the use of 6 axis robots for deployment of NDT probes in these inspections. A new system for robot deployed ultrasonic inspection of composite aerospace components is presented. The key novelty of the approach is through the accommodation of flexible robotic trajectory planning, coordinated with the NDT data acquisition. Using a flexible approach in MATLAB, the authors have developed a high level custom toolbox that utilizes external control of an industrial 6 axis manipulator to achieve complex path planning and provide synchronization of the employed ultrasonic phase array inspection system. The developed software maintains a high level approach to the robot programming, in order to ease the programming complexity for an NDT inspection operator. Crucially the approach provides a pathway for a conditional programming approach and the capability for multiple robot control (a significant limitation in many current off-line programming applications). Ultrasonic and experimental data has been collected for the validation of the inspection technique. The path trajectory generation for a large, curved carbon-fiber-reinforced polymer (CFRP) aerofoil component has been proven and is presented. The path error relative to a raster-scan tool-path, suitable for ultrasonic phased array inspection, has been measured to be within ± 2mm over the 1.6 m 2 area of the component surface.

Automated optimization of complex three-dimensional robot trajectories

“…During the analysis, it had been evaluated, that by the optimization a regular distance of the tool tip relative to the substrate and additionally a continuous relative velocity is achieved (3), (4). Hence, it can be anticipated, that in course of the real process a good and continuous process result is obtained.…”

“…surfaces or edges ofthe 3D work-piece model are detected and the robot tool path is automatically generated considering specific process settings like machining angle, tool type or processing speed [3]. Some tools as weIl allow apredetermination of motion strategies of the robot relative to the work-piece surface [4]. Further features comprise a digital representation of the process result like a colorization of the layer thickness wh ich results from a robot based coating [5].…”

Advances in the UK Toward NDE 4.0

“…Past NDE research efforts worth highlighting given close links to the vision of NDE 4.0, without necessarily having been carried out in that context, include work on modelassisted probability of detection (MAPOD) [17], model-assisted inspection qualification [18][19][20], model-assisted data analysis [21][22], inspection optimization [23], data fusion [24], as well as inspection-based simulation [25][26][27] and machine leaning, even applied to a traditional, "wet" inspection technique [28]. Work on advanced robotic inspection and un-conventional inspection delivery systems, including collaborative robots (cobots) and unmanned aerial vehicles / drones, are worth highlighting, too, performed especially by the research and technology organization TWI and Strathclyde University [4,[29][30]. Moreover, given the role of condition monitoring in NDE 4.0, using embedded sensors to inform a "live" assessment of the state of an asset, much of structural health monitoring (SHM) [31] is broadly relevant and will be further exploited as we move further towards fully digital and connected NDE.…”

PAUT inspection of complex-shaped composite materials through six DOFs robotic manipulators

“…The goal is to be able to load the inspected component geometry CAD file into a software application, to allow the operator to pick the areas to be inspected and for the software to then generate the scan path for the robots. OLP was achieved within the IntACom project using commercial robotic simulation and programming software [11] . The chosen software was CENIT-FastSurf [12] , based on a Delmia platform [13] .…”