Weight reduction has been the main reason to change from metals to composite materials in aircraft structure. Aviation regulation bodies require to perform inspections during manufacturing (100% quality assurance in primary parts), regular checks during operation and after incidents (such as bird strikes, hard landings or similar incidents). Given all that, the increasing use of composites in aircraft poses numerous challenges to current inspection capabilities in terms of:
• Complex parts and structures sometimes are difficult to reach in their full extension and have variable thickness, making inspection operations difficult.
• Delamination and cracks in the composite are usually internal, not visible from the surface. Internal defect inspection techniques are required, e.g. ultrasonic technology.
• Traceability of inspection process.
• Support operator activities/decisions.
• Safety assurance for those workers in the proximity of the inspection robots.
• Inspection instrument positioning and manipulation. This aspect is critical particularly for curved and complex shapes of composite parts. Part variability is an additional challenge.
• Cost-effective integrated solutions based on collaborative robots, safety mechanisms and inspection equipment.
Ultrasonic testing (UT) techniques are suitable for the inspection of large and hidden areas and recently developed ones, like guided waves, have shown potential for remote inspection. Currently, most of inspections are performed manually, which entail two key disadvantages: an excessive amount of time and the possibility of potential safety failures due to human errors. To solve these issues, automation of inspection process has been envisioned as strategic solution. The integration of robotics in manufacturing lines has proved improvements in process reliability, reduction of manufacturing times and, therefore, costs. However, many industrial operations cannot be fully automated at a reasonable cost. In such a case, human-robot cooperation may be the most cost-efficient and productive solution.
CRO-INSPECT has developed a new concept of hybrid work cell for inspection, where humans and robots perform collaboratively inspection activities using advanced UT techniques.
The specific goals of the project have been to generate an advanced and safe human/robot collaboration work cell prototype for robotic assistance of the operator during inspection; and to generate a new inspection system based on advanced UT, capable of reaching low access areas of parts.
