Gilbert Ossbahr

Modular and Configurable Steel Structure for Assembly Fixtures

ABSTRACT This paper will present the latest development of a configurable and modular steel construction system for use in frameworks of flexible fixtures of the kind called Affordable Reconfigurable Fixtures (ART). Instead of a dedicated aircraft fixture, which is very time consuming and expensive, the ART fixtures enable affordable construction from a standard component kit, by solving the main draw-backs of traditional tooling. In early 2009 Airbus UK built the first steel modular fixture for the aerospace industry. The project was a partnership with DELFOi and Linkoping University in a project called ReFlex, Reconfigurable Flexible Tooling. A paper was presented in the last year SAE conference which explained about the project in overall. The construction system called BoxJoint has recently been tested in some manufacturing areas at Airbus UK and also been applied in the production at Saab Aerospace Linkoping Sweden. A case study was conducted of an A380 subassembly fixture demonstrating the comparable advantages of the new technology from the design phase until the first aircraft build. One of the benefits reported is that a modular fixture relatively quickly can be assembled and set within specified tolerances by means of a metrology system, guiding configurable pickups and flags called Flexapods. Calculation of strength and stiffness can be made by simple standard methods.

Low-Cost Automation for Aircraft Assembly

In this paper solution for low-cost automation of aircraft assembly is presented. The concept of this development is closely related to “Lean Automation”, which in this case concerns the use of modern standard equipment such as standard robots, PC-computers and a newly developed spatial sensor system for precision measurements of positions. The robot is used to perform reconfiguration of tooling modules that are possible to be configured/reconfigured in six degrees of freedom. A prototype developed as the result of an EUproject called ADFAST* has been evaluated at Linkoping University in Sweden. Technical functionality is reported where the robot manages to configure the flexible tooling modules to a total error bellow 50 µm. This paper presents the results on the portion of the project addressing robot, metrology system and tooling.

Force Feedback for Assembly of Aircraft Structures

Variability in composite manufacture and the limitations in positional accuracy of common industrial robots have hampered automation of assembly tasks within aircraft manufacturing. One way to handle geometry variations and robot compliancy is to use force control. Force control technology utilizes a sensor mounted on the robot to feedback force data to the controller system so instead of being position driven, i.e. programmed to achieve a certain position with the tool, the robot can be programmed to achieve a certain force. This paper presents an experimental case where a compliant rib is aligned to multiple surfaces using force feedback and an industrial robot system from ABB. Two types of ribs where used, one full size carbon fiber rib, and one smaller metal replica for evaluation purposes. The alignment sequence consisted of several iterative steps and a search procedure was implemented within the robot control system. The technology has the potential to lessen the need for dedicated tooling, reduce the need for traditional workspace calibration and can be used in several other applications, such as pin and socket type assemblies found in pylons or landing gear or “part to part” assemblies such as leading edge ribs to spar.

A Study of the Influence of Drilling Method and Hole quality on Static Strength and Fatigue Life of Carbon Fiber Reinforced Plastic Aircraft Material

Study of the Inluence of Drilling Method and Hole quality on Static Strength and Fatigue Life of Carbon Fiber Reinforced Plastic Aircraft Material