Robots become precision tools

Robots are the allrounders of modern manufacturing – until they encounter solid steel or complex milling paths. That’s when the big tremor starts. Because what standard industrial robots offer in flexibility, they lack in stiffness. This is precisely where a joint development by Siemens and the Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM) in Stade comes in: a novel hybrid drive that literally gives robots new power – without sacrificing precision. The development has earned Stephan Hansen and Tobias Hamann from Fraunhofer IFAM and Sven Tauchmann and David Bitterolf from Siemens this year’s Inventor of the Year Award in the “Open Innovation” category.David Bitterolf explaining an idea to his co-inventors

Working together is a win for precision

The concept is based on combining two fundamentally different types of drive: direct drives work with high precision and speed, but would become too heavy and too expensive if used as the sole drive system. Indirect drives are robust and powerful, but less sensitive. By intelligently combining both systems in a single drivetrain, a hybrid drive is created that offers the best of both. The result is a robot that remains stable and low in vibrations even at high feed rates – thus approaching the precision of classic machine tools.

Four minds, one idea

It was the joint expertise of the four researchers from industry and science that made this innovation possible. While Hansen and Hamann provided the scientific foundations and control logic, Tauchmann and Bitterolf contributed years of industrial and application knowledge in robotics. Siemens and Fraunhofer have long enjoyed a trusting partnership, collaborating on joint projects, some of which are publicly funded. This allows both sides to pool their resources. “We also have good chemistry on a personal level, creating a working environment in which we can try out and implement new ideas quickly,” explains Tauchmann.

Sven Tauchmann (Siemens Digital Industries Motion Control, Safety & User Technology)

Where additive meets subtractive – two processes, one robot

This invention enables a robot to work both additively (adding material) and subtractively (removing material) – in other words, we have 3D printing and milling hard materials like steel within one system. A component is created layer by layer and then expertly refinished without the need to re-clamp or change machines. Ultimately, the robot becomes a kind of Swiss Army knife for manufacturing – depending on the task, it can print, mill or repair,” explains David Bitterolf. This not only saves time, energy and costs but also space in manufacturing. At the same time, processes become more flexible and sustainable – an important step toward resource-efficient production systems.

David Bitterolf (Siemens Digital Industries Motion Control, Mechatronic Support)

From lab to application

The innovation has long left the research stage and is already being tested in initial pilot projects with industrial partners. The main goal is to demonstrate that robots with the new drive can reliably follow paths even in demanding machining tasks. This opens up new potential for small and medium-sized enterprises - through more compact, more efficient manufacturing cells, processes can be rethought, or untapped automation potential can be unlocked. One example is the unification of additive and subtractive processes within a single robotic cell.

Stephan Hansen (Fraunhofer IFAM Stade, Automation and Production Engineering)

What drives the developers

“Real-life customer problems are the best inspiration for new ideas,” says Bitterolf. For Tauchmann, team spirit is crucial. “If you coordinate well on the pitch, you score the best goals.” What Hansen values in particular is the combination of doing research and nurturing young talent: “Mentoring young colleagues over several years and seeing results together is incredibly motivating.” And for Hamann, the award fulfills a childhood dream: “Inventor is not a profession you can apply for. It’s an attribute you can earn and wear with pride,” he explains.

Tobias Hamann (Fraunhofer IFAM Stade, Automation and Production Engineering)

Looking ahead

The new drive architecture opens up groundbreaking possibilities in robot axis control. The partners are currently working on optimizing the algorithm and examining how the hybrid principle can be transferred to other machine classes. The goal is a new generation of industrial robots that combine maximum path accuracy with precision, versatility and sustainability in milling and application processes – an example of how close cooperation between research and industry is pushing technological boundaries.

Robot in action
Fraunhofer IFAM’s research acitivities
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