Automating wing assembly

Citation

(2001), "Automating wing assembly", Aircraft Engineering and Aerospace Technology, Vol. 73 No. 4. https://doi.org/10.1108/aeat.2001.12773daf.005

Automating wing assembly

Automating wing assemblyKeywords: Airbus, Automation, Wings

Airbus UK is the UK's national entity of the Airbus company. In June 2000, BAE Systems and EADS, then partners in the Airbus Industrie consortium, announced the formation of a new Airbus Integrated Company (AIC). The new company which began operating on 1 January 2001, is known simply as "Airbus" and incorporates Airbus Industrie and all the major Airbus activities of BAE Systems and EADS.

Airbus has built up a full range of aircraft to comprehensively cover airline needs in the 100-plus seat airliner market. The Airbus family includes the newly launched doubledecker 555 seater A380, the short-to-medium haul 124-seat A319, 150-seat A320 and 186-seat A321 together with the A318 – a new 107-seat version which was launched early in 1999; the medium to long range 220-seat A310 and 266-seat A300-600; the medium to long range 293 to 335-seat A330 and the very long range 239 to 295-seat A340. The new, extended range A340-500 and the A340-600, which will seat 380 passengers in three classes – will enter airline service in 2002, and orders and commitments for over 100 of these aircraft have been received.

The prime industrial responsibility of Airbus UK is the design and manufacture of high-technology wings for all Airbus models as well as overall design and supply of the fuel system. For most Airbus models the company is responsible for overall design and supply of landing gear and, in the case of the A321, overall design and manufacture of one section of fuselage. In general terms other production responsibilities are as follows; Airbus France – the nose, flight deck and flying control systems, Airbus Deutschland – the fuselage sections and Airbus España – the tailplane.

Airbus UK's headquarters are located at Filton, Bristol which is also home to its main design and engineering facilities. Its manufacturing activities are undertaken primarily at Broughton, Flintshire, North Wales and some manufacturing is undertaken at Filton. Together these two sites employ around 9,500 people. Major contributions are made by other factories of BAE Systems, as well as by risk-sharing subcontractors both in the UK and overseas.

Final assembly of the wing box structure for all Airbus models takes place at Broughton from parts and sub-assemblies produced there and at various factories. In the case of the A319, A320 and A321, the wing is completed at Broughton by the addition of hydraulic, air and electrical systems. Flying control surfaces are fitted and all systems tested before the sets of wings are transported by air to the aircraft final assembly line which is in Toulouse for the A320 and Hamburg for the A319 and A321. Wings for the "widebody" Airbus airliners leave Broughton to be equipped by Airbus Deutschland in Bremen, Germany. Airbus UK is also responsible for a section of A321 fuselage, which is assembled at Filton.

The record growth in aircraft orders and increasing production rates is encouraging Airbus UK to build on investments and improvements already made to its wing assembly process.

The second phase of a major research project was recently unveiled by the company at its facility in Broughton, North Wales. The automated wing box assembly project (AWBA II) integrates, for the first time, handling, positioning, measuring, robotic drilling, wing skin panel wrapping and fastening technologies in a single 8.5m high demonstrator (Plate 1). The project has received part funding of £5 million from the Department of Trade and Industry under its Civil Aviation Research and Demonstration (CARAD) programme.

We understand that the test work to date has met all expectations; according to Airbus UK the demonstrator cell has already proved the concept of wing skin panel wrapping and is capable of handling and positioning a 6m high wing rib quickly and safely. Throughout this year all operations in the AWBA cell demonstrator will be evaluated to measure cost, accuracy and repeatability compared to manual assembly methods. Airbus UK will also be assessing "scale up" implications, the impact on aerodynamics and systems, and health and safety. It is expected that the technology will, in the future, make the assembly process more efficient, further reducing costs and lead times.

Plate 1 AWBA II cell demonstrator of Airbus UK, Broughton, North Wales

AWBA II is a partnership of seven UK-based companies, each responsible for designing, manufacturing and evaluating different elements within the cell demonstrator. Partners and responsibilities are as follows:

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  Airbus UK at Filton, Bristol and Broughton, Flintshire (project management and provision of facilities and materials).

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  AEA Technology, Culham, Oxfordshire,(robotic fastening process control).

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  AMTRI, Macclesfield, Cheshire (automated handling and positioning systems).

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  BAE Systems Advanced Technology Centres – Sowerby, Filton, Bristol (vision and sensor systems).

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  Leica, Milton Keynes, Buckinghamshire (measuring systems).

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  RTS Advanced Robotics, Trafford Park, Manchester (robotic technologies).

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  Tecnomatix, Sutton Coldfield, Birmingham (software and simulation packages).

AWBA II, which began two years ago, builds on the work of AWBA I which approved an original concept for automated assembly and developed four individual demonstrators to understand robot positioning, skin panel to rib feet robotic drilling, skin panel positioning and wrapping and process control.

Paul Chivers, director of Research, Evaluation and Test at Airbus UK said: "AWBA II is a fine example of how UK companies, with the support of CARAD, are able to pool their knowledge and expertise in developing technologies to benefit the manufacturing industry. I look forward to the results of the evaluation work which will be carried out this year".

A leading company in the partnership is AMTRI which specialises in advanced machinery technology and providing cost effective solutions associated with the design, construction, application and performance of manufacturing machinery and automation systems.

The involvement of the company in the AWBA II project is a prime example of the company's broad technology base and its ability to communicate to its clients all consequences of decisions relating to processes and design.

The company's responsibilities in the AWBA II project included generation of the original system concept. The concept design and the design and build of the gantry and sub-systems. Installation of wiring and commissioning, cell safety and the design review for the internal robot. It also participated in the development of the metrology methodology and in the development of the cell control system methodology.

Most of AWBA II's sub-systems were also designed and built by AMTRI.

Another partner in the AWBA II consortium is AEA Technology whose principal contribution to the project was to optimise the wing component drilling parameters in order to maximise hole quality and minimise burr size. Additionally its aim was to optimise and perfect the efficiency and speed of the drilling cycle without sacrificing hole quality. AEA carried out a whole series of drilling tests using a manufactured fixed test bed as well as conducting extensive robot based drilling tests using a robot-mounted drilling end-effector. On completion of these trials AEA also undertook modal analysis and vibration trials on the robot to see what effects if any these factors might have on hole quality and accuracy when automatically drilling.

General observations and conclusions

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  Material type had the biggest impact on hole quality. Aerospace grade metals vastly improved results over commercial grade materials.

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  Lubricants (BCO14 and RTD) improved quality.

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  Little difference in quality between high-speed steel and carbide drill bits.

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  Best quality is achieved in aluminium alloys between 4,000-8,000rpm and low feed speeds.

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  No deterioration in hole quality detected at or near vibration modes.

The test/trial results show that for the fastest drilling of holes without sacrificing hole quality and burr size:

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  spindle speed should be set to 4,000-8,000rpm;

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  feed speed should start at 5.5mm/s and be reduced to 1.5mm/s just before breakthrough.

ATC-Sowerby's main role in the AWBA II project has been to provide a set of key technologies for the project demonstrator cell. In addition, through a close collaboration with Airbus (Filton and Broughton), the company believes that it has made a significant contribution to the design of the overall cell demonstrator.

The company's technology contribution to the project has been in three key areas. It has adapted a conventional Kuka 350 robot to make it suitable for drilling and fastening operations. This included the equipping of the new end-effector and the addition of a seventh axis.

In addition it specified and commissioned a new drilling and fastening end-effector (DDEE). Evaluation trials have been performed to optimise the drilling parameters and to determine the stability of the Kuka robot during drilling and fastening.

A sensor of its own design has been fitted to the external robot to provide a high-precision positioning capability. Information from the sensor (based on two cameras and four laser rangefinders) is used to set up the robot drilling positions for each rib-foot.

A vision sensor to guide the internal robot into the correct position for bolt swaging has also been developed. Detailed calibration has enabled high positional accuracies to be achieved.

It is a fact that aircraft components cannot be built without demanding metrology control from a few tenths of milometers down to a few tens of microns. This very high accuracy must be maintained even for very large components, which may be 30 metres or more in size. Leica Geosystems considers that the evaluation in the AWBA I project as well as current industrial practice, point to laser trackers as the most appropriate large scale metrology tool to monitor and control wingbox construction.

For the AWBA II project Leica Geosystems applied and further developed laser tracking systems. The objectives in general are:

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  Support the move towards jigless manufacture through the use of optical metrology during construction.

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  Provide metrology control for positioning parts and manufacturing robots.

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  Apply new techniques to enable higher degrees of automation.

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  Increase the scope for application of trackers within confined environments.

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  Ensure that new wingbox design and construction methods integrate tracking technology in an optimal way.

As the project neared completion Tecnomatix took on the responsibility for producing a consolidated demonstrator cell simulation model (using final data models from each of the project partners). We have also completed a simulation model showing the application of the AWBA demonstrator principles to the automated assembly of a complete wing box – a full-scale production mock-up.

Robotic off-line programming – today used for up to 75 per cent of robotic programming in the automotive industry – has been successfully used to dramatically improve the productivity of programming the robot movements for the AWBA II cell.

The project partners have used 3D simulation modeling of the AWBA II demonstrator cell during the entire project. This has helped the partners to understand the various sub-system interactions, to provide a visual tool for developing the cell sequence of operations, to support line-of-sight studies (particularly useful for confirming the feasibility of the measurement systems) and as a tool for reviewing progress at project review meetings. Tecnomatix has authored a document detailing the methodology for maintaining a "master" cell simulation model – and distributing this data to the project partners.

As the project reached its later stages Tecnomatix completed packages of work to produce final simulation models of both the AWBA II demonstrator cell and a full scale full-wing production cell (applying the basic automation principles of the AWBA II cell).

This final simulation model contains all of the major steps of the AWBA demonstrator cell. The simulation model provides the ability to view the entire build process in 15 minutes. The company is able to interact with the model during playback by; changing its viewpoint, creating different camera views and checking for line-of-sight.

An "mpeg" movie file (which can be run on a standard PC) has been produced to show the entire demonstrator sequence and many still images have also been captured.

Tecnomatix have worked with Airbus to produce a full production cell simulation model. This production system scales up the demonstrator basic principles to explore a possible production system scenario. This simulation model can now be used to assess the physical feasibility, cycle time, operation sequencing and likely cost of a full-scale production facility.

The full-wing production "sequence of operations" and the simulation model creation tasks were both documented by Tecnomatix, and are submitted as part of the final project documentation. An "mpeg" movie file and many still images have also been produced from this simulation model.