Lufthansa Technik is developing a second generation of its fuselage-inspection demonstrator robot.
Over the past three years, the German MRO provider has co-operated with partners to build the "mobile robot for fuselage inspection" (MORSI), under the auspices of a partly government-funded research project. The system uses suction pads to automatically move across aircraft fuselages, and is equipped with an induction heating system and thermography camera to detect cracks in metallic structures.
Though it is a technology demonstrator, the system was specifically developed to automate regular inspections of chemically milled pockets in the airframe structures of Boeing 737 Classics. Now, the engineers want to build a successor robot that is smaller, more lightweight, and faster, says Stefan Mehler, project manager of innovation at Lufthansa Technik in Frankfurt.
The existing system is about 140cm (55in) wide and weighs around 75kg (165lb). It has been tested on a de-registered, former Lufthansa 737-500 used for training at the MRO provider's base in Frankfurt. The trial showed that the robot can even support itself in upside-down positions on the lower parts of the fuselage. But the design still needs improvement as there is a certain elasticity within both the airframe and the robot's own structure, which can compromise the effectiveness of the attachment and motion system.
The equipment was secured by a safety cable throughout the trial. But this is to abandoned for the next robot generation, says Mehler. An additional aim for the successor model is to improve the robot's capability to determine its position on the aircraft and navigate across the fuselage. The current system uses rivet rows for its positioning calculations, but this could be compromised if an aircraft has a structural repair patch with additional rivet rows.
While the existing equipment uses its thermography camera for both the inspection and navigation, the team is planning to have separate sensors to ensure reliable positioning data and that the robot can be reconfigured for different non-destructive inspection techniques.
The engineers are evaluating different sensor technologies. Laser-based systems could be employed to navigate based on "natural landmarks" such as material joints in the aircraft's surface, says Mehler. But it would also possible to employ artificial features, such as barcode stickers.
The objective is to automate inspections for both metallic and composite fuselage structures. But rather than attempting to inspect entire aircraft, development will focus on inspections that create a high volume of repetitive checks. Mehler says it makes no sense to develop a system capable of inspecting areas with complexities – such as fuselage-mounted antennae – if such are encountered in only few locations on the aircraft. But if a robot can take over checks that need to be conducted across large parts of the fuselage surface, the savings over labourious, manual inspections could be significant, he says.
Source: Cirium Dashboard
