Aerospace assembly is characterised by the tight tolerances required – deviations over 0.1mm from nominal can cause significant aerodynamic effects. Simultaneously, aerospace components need to be lightweight, and are often flexible until assembled into their final structure.
Commonly, large jigs and fixtures are used to ensure alignment in aerospace assembly, but these are costly and time consuming to create, and represent a substantial cost, particularly for low batches of aerostructures.
FA3D utilised advanced metrology systems such as laser radar and optical coordinate measurement machines to achieve accurate measurement of parts over large volumes.
Data from these metrology readings is directly integrated with the robotic controllers to adjust the positioning of parts to bring them back into tolerance, and hold them in place while fasteners are inserted, effectively replacing the need for fixtures.
| Country: | GB |
| Address: | Advanced Manufacturing Building, 522 Derby Rd, Lenton, Nottingham NG8 1BB |
Though the integration of adaptive robot control represents a significant upfront cost, the ability to save money on fixturing in the long term makes the creation of low batches of large, accurate products a more realistic proposition for small to medium enterprises.
As the robots can be re-used over and over for different situations, it enables significant flexibility in what products and product variants can be built.
The ARC robotic control system is extremely effective for bringing a robot / part to a specific and highly accurate location. However, it does not allow for accuracy along a path, so would not be appropriate for continuous path accuracy e.g. robotic milling or welding.
The large amount of metal in the cell (robots, parts) dramatically lowered the accuracy that was possible with the RFID positioning system. Rather than being able to track parts to a specific location, we could determine no better than if a part was inside or outside the cell. Active RFID tags may help mitigate this.
K-CMM technology was extremely effective, but subject to line-of-sight restrictions for large assemblies such as aerospace fuselages.
When integrating technologies and solutions from multiple equipment vendors, the challenge is almost always interoperability and standards compliance. The ARC system was comparatively simple to integrate and commission, but integration into the larger context of a manufacturing process with a SCADA and other physical devices was more of a challenge.
RFID Positioning System – Use of multiple RFID receivers within the cell would allow for 3D location tracking of the parts to be assembled in the system, ensuring parts are correctly present and in the right locations before proceeding.
Nikon K-CMM Metrology - By positioning LEDs on the robot end effector, and on the target parts, the K-CMM system can measure relative positioning to a very high degree of accuracy even over large distances.
Nikon Adaptive Robotic Control (ARC) – this technology allows data from metrology systems to correct a robot controller’s coordinate system and compensate for inaccuracies and variability.
KUKA Robotics – Compatible with the ARC system, the KUKA robots were used for part positioning.
Integration of adaptive robot control technology into a complex and variable manufacturing process allows for accurate positioning of assembly components despite variability in component manufacture, existing assembly deviation, and the robots themselves.
This allows for progress towards jig-less assembly – saving non-recurring costs in the assembly of large, low batch products. Rather than building large, welded jigs and fixtures, robots are used to position and align parts. As the robots can easily be reused, this saves significant time and money.
Note: Since this demonstrator implementation, the Adaptive Robot Control and K-CMM technologies are now available from True Position Robotics .