Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - CRO-INSPECT (Collaborative RObotic Solution for Advanced Inspection of Complex Composite parts)

Teaser

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...

Summary

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.

Work performed

The project activities during this period have been focused around specifying and building inspection technologies that provide solution to CRO-INSPECT project aims. The focus is in building on the one hand, a flexible robotic cell to assist inspection activities. And on the other hand, to analyze guided waves technologies for inspection of low access parts.
The main element used to define and evaluate the technologies is an aileron designed and manufactured by SAAB.
During this period six work packages have been activated, four technical and two devoted to management and dissemination and exploitation activities.
WP2, main focus is on scenario needs identification that has been used as requirements input to the WPs focused on technological developments. This WP has already finished producing as output the final solution design that is described in D2.2 “Work cell design and system architecture for collaborative inspection”. In this solution requirements coming from SAAB for the inspection of the aileron using collaborative robotics technology and guided waves have been considered, described in D2.1”Part inspection identification requirements specification” a document that performs an analysis of the different requirements and its technical implications.
WP3 active safety system development for human robot collaboration is still running, it focus mainly on the definition and implementation of pre-collision strategies. The solutions adopted are compliant with current safety norms: Safety-rated monitored stop, Hand guiding, Speed and separation monitoring and Power and force limiting. At the end of WP3 first prototypes of Active safety system are available including functionalities for Human detection and tracking and Pre-collision strategies implementation. The related milestone “Human monitoring system in collaborative area” has been achieved.
In WP4 adaptive control system development and collaborative control management is still running. A set of force based control modules have been mainly implemented at this stage. Specifically, these modules allow the robot to adapt to the surface to be inspected and to ensure alignment of an ultrasonic probe considering both position and force.
WP5 for ultrasonic techniques development based on guided waves is running, the main objectives is to analyse the capacity of UT techniques, including Guided Wave Technique, for the inspection of low access composite parts and develop specific procedures for the remote inspection of parts with low access. Several works have been done during this period, it is worth to mention the following ones: Numerical prediction of Dispersion Curves and Mode Shapes, theoretical analysis of Input Signal, Test in representative samples

Final results

The project develops several innovative technologies related to robotics and ultrasonic inspection.
The approach uses state of the art collaborative robots, in a mobile manipulation configuration which increases the system flexibility. CRO-INSPECT is developing monitoring systems for safe human-robot workspace sharing by combining different sensors. Trajectory planning algorithms in order to avoid collisions are also developed. This will allow to overcome the limitation of traditional robotic approaches that normally are fixed and safe using fences. To increase the adaptability of the whole robotic solution several adaptive strategies to be used depending on the inspection task and stage are considered. On the one hand, adaptive trajectory planning that makes use of perception for part and environment mobitoring. On the other hand, adaptive force control strategies using variable stiffness approach and adaptive control based on ultrasound inspection feedback.
The main innovation comes from the usage of GWT for the remote inspection of areas with low accessibility. The development of this technique which is at higher TRL for metallic parts and pipeline geometries has a number of challenges in low access areas of composites.
CRO-INSPECT Key exploitable results are mainly:
• The complete system (demonstrator): the hybrid cell (robot-human) for complex composite parts inspection (aileron), including sensors, algorithms… that implement the autonomous inspection strategy combined with human presence.
• Inspection method using adaptive control of a robotic arm, for ultrasonic inspection sensors (rollscan).
• Procedure for Ultrasonic inspection of low-access areas.

Website & more info

More info: http://cro-inspect.eu/.