Detection of Hidden Substructure Edges and Holes

Pacific-Sierra Research Corporation (PSR) proposes to develop a robotic alignment system for aircraft assembly using its non-contact thermographic technology. This automated robotic-thermographic positioning system will be capable of accurately locating and monitoring subsurface holes and edges under exterior panels or skins. The non-contact thermographic system will include a portable high-speed infrared camera with enough spatial resolution, thermal sensitivity, and modern image-processing tools to characterize hidden holes and edges in structural components. This methodology uses a photothermal xenon flashlamp pulse to generate a steep momentary temperature gradient in the material. Subsurface hole regions will restrain the passage of heat, causing the flaw areas to be contrasted against the surroundings when viewed with a thermal imager. The dependence of the transient response on hole and edge locations beneath the surface will be investigated. The temperature history of the surface temperature after the absorption of the short photothermal pulse is used to locate the subsurface holes of the aircraft panels under test. A graphical user interface windowing environment is used to display the entire inspection on a high-resolution monitor; the instrument then, automatically and accurately marks the hole locations with little operator intervention. This robotic-thermographic system will greatly reduce the time and cost associated with examining aircraft structures. A potential Phase III partner has been identified and contacted.