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Robotic Metrology-Assisted Assembly Combines Photogrammetry with Laser Tracker

Hexagon’s Manufacturing Intelligence division has announced the installation of a new automated inspection system custom-built to meet the large-scale needs of wind turbine manufacturer Siemens Gamesa Renewable Energy. Now operational at the Siemens Gamesa Cuxhaven offshore nacelle assembly plant in northern Germany, the unique installation combines the power of photogrammetry, laser tracking and robotic automation to deliver a high-productivity solution for aligning the large flexible stator components of generators used in direct drive wind turbines.

The system uses a custom-developed four-camera 3D Arena photogrammetry system with a robotic calibration tool in combination with a Leica Absolute Tracker AT930 and a mounted constellation of ultra-wide-angle Super CatEye reflectors. The system represents an example of  metrology-assisted assembly, a growing field that applies high-accuracy measurement devices to make sure a complete product is constructed to the same degree of accuracy as its individual components are designed and manufactured.

“With this project we’ve engineered a new type of system that gets results within required tolerances at a greater level of productivity than was previously possible, and with great potential for continued development,” said Duncan Redgewell, President, Metrology Devices at Hexagon. “This is a project that really shows off the strength of the product portfolio available from Hexagon – I don’t think any other company in the manufacturing inspection sector has the hardware knowledge required to develop a single integrated system that combines photogrammetry and laser tracker technology so seamlessly.”

Direct measurements of the stator and mounting area are collected using the 3D Arena cameras, while the Absolute Tracker is responsible for maintaining an accurate single frame of reference across every aspect of the system, using its large-scale absolute positioning capabilities to ensure placement accuracy to within just 150 microns when assembling stator panels up to 12 metres across. The concept emerged from close cooperation between the Offshore Operations Innovation team at Siemens Gamesa and the photogrammetry and laser tracker technology experts at Hexagon, as well as with third-party integrator ARGON, who developed the metrology software and automation aspects of the project on the foundations of Hexagon’s SpatialAnalyzer platform.

“This has been a fantastic project to be a part of, involving some really inspiring technical collaboration and innovation,” said Geert Creemers, Founder and Co-CEO at ARGON. ”An important aspect of the project for the Siemens Gamesa team was the capacity for shop-floor users to work with the system end-to-end without the need for long and complex training. We like to think of metrology as just another tool, so we focus on making it as simple to apply as possible when we develop our measurement integration systems. We call that the ‘coffee machine principle’, and it has been a central concept in developing this system for the team in Cuxhaven.”

While the initial design concept deals with stators measuring six metres across, the Siemens Gamesa team is focused on the future and the need to produce even larger systems to meet the demands of the offshore wind energy industry.

“We at Siemens Gamesa are driven by continuous innovation,” said Marius Fuerst-Sylvester, Calibration Engineer at Siemens Gamesa. “Our technology that’s used to produce clean energy from the wind has made tremendous progress due to our ongoing efforts to do things better, both in our product development and in the production of our turbines. Very soon we’ll be regularly dealing with stators that are even larger as our portfolio grows. Safely and reliably assembling bigger components requires more than traditional, manual methods. With the new 3D Arena-Tracker system from Hexagon and ARGON, dealing with larger components benefits all parties.”

It’s foreseen that the project will continue to develop, with an expectation that the current manual adjustment of stator segments will in the future be replaced by an entirely automated adjustment process. This has the potential for further time- and cost-saving, significantly increasing the productivity of this important site for Siemens Gamesa’s Offshore Business Unit.

“The time-consuming method of adjusting the accurate distance between magnets and stator is crucial to efficiency,” said Benjamin Henriksen, Production Specialist at Siemens Gamesa. “We had the idea to automate at this point and use digital technology to make production easier and smarter. Solutions like the one developed with Hexagon and ARGON enable us to achieve a more accurate assembly and higher productivity, making Siemens Gamesa’s manufacturing smarter.” 

“The project “Flexible nacelle production for wind turbines of the future in Cuxhaven” (FLECX) is funded by the European Union, the State of Lower Saxony and NBank. FLECX develops the fundamentals for digitally supported assembly processes for future offshore wind turbines that are adapted to component properties.”

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