Simply suited for the job: the cost-effective and powerful cobot solution from thyssenkrupp Automotive Systems

"Cobots" are collaborative robots. They work together with humans in the production process but are not kept apart from humans by protective devices, as is usually the case with industrial robots. A cobot pilot project is now being successfully implemented in series production at the thyssenkrupp plant in Hambach, France. Project manager Gilles Gaeng reveals the potential that cobots offer to the thyssenkrupp Group.

In the French town of Forbach, thyssenkrupp Automotive Systems is working on the future of automotive production: the Center of Competencies (CoC) is developing new production concepts and applications within the ambit of Industry 4.0. One of the fields they are focusing on is research into human-robot collaborations. Since the beginning of 2023, the first collaborative robot has been assisting colleagues in axle assembly for smart at the thyssenkrupp plant in Hambach, France. The cobot has already proven its worth there.

Gilles Gaeng, Technical Manager and Maintenance Coordinator at the CoC, saw an urgent need for action. And with Gilles not only being an expert in production but also the TPM coordinator for the Total Productive Maintenance program – i.e. the continuous improvement of production systems – at thyssenkrupp Automotive Systems, he identified potential for a pioneering cobot pilot project. The objective: to integrate a cobot particularly effectively as a complement to existing collaborative robots in the Group.

Gilles has already been dreaming of a truly collaborative industrial robot for more than three years: "Everyone is always talking about collaborative robots, robots that work with humans," reports Gilles, "but if you look closely at how these cobots work, there are barriers and safe zones all over the place. True collaboration just isn't taking place there. I definitely wanted to build the first application without barriers, without safety scanners. Back then, I'd only seen something like this in the lab and at trade shows – never really and truly in production. A suitable opportunity presented itself in Hambach."

Here, among other things, thyssenkrupp Automotive Systems assembles rear axles of the smart subcompact car for a customer. The transmission must be filled with oil during assembly of the transmission and the engine. "This unergonomic process used to be really awkward for our workers," Gilles recalls. "There was a heavy adapter suspended overhead, which they had to pull down and hook onto a mounting plate, then push it into the transmission with 3 kg force and hold for 5 seconds until the process was complete."

In addition, there was a risk of incorrect operation: if the adapter was not inserted at right angles into the transmission nicely within the close tolerances, there would be an oil leak. "The job of cleaning the mounting plate was one that we needed to do every hour if not more often. We also had to get an external service provider to clean the floor twice a day," reveals Gilles. As a result, not only was valuable cycle time lost, but also gear oil. At the same time, the process caused us avoidable costs on an ongoing basis.

For Gilles, the answer was clear: a collaborative robot would deliver nothing but benefits here in close cooperation with the colleagues in production. However, ordinary cobots are extremely expensive. "In our application, the cobot wouldn't have paid for itself within the lifetime of the project," Gilles is certain. But this failed to dissuade Gilles and his team. They researched on the Internet, visited trade shows – and indeed managed to find what they were looking for.

Well suited for the job

Gilles came across the Austrian company Airskin and its product: sensitive suits for robots that turn ordinary industrial robots into collaborative workers. They use electro-sensitive sensors to detect collisions, creating a safe workplace where humans and robots can work together freely without a protective fence. As it turned out, this suited Gilles and his team down to the ground.

The robot was fitted for its suits in Austria, along with the necessary equipment. This involved applying the pressure-sensitive pads only to those areas, or rather axes, that really needed them. The result is not only a cost-effective solution but also a high-performing one. "We're talking about a cost of about half that of a new cobot," says Gilles enthusiastically, "and what's more, we were able to do all the integration in-house."

Programming expertise delivered the breakthrough

However, Gilles and his teammates had to overcome a number of hurdles before the cobot worked the way they intended it to. During those first few months, there were honestly times when we wanted to throw in the towel," reveals Gilles. "100-percent collision safety was difficult to achieve at first. But we refused to settle for anything less than 100 percent; after all, the safety of our fellow workers is our top priority." Undaunted, the CoC engineer Clémence Pissavin and electrical engineer Hervé Brunagel finally cracked it. "They wrote a script that allowed us to additionally use the robot's force sensor as well to make really sure that there was no danger to production workers. That was the breakthrough," says Gilles happily.

The testing organization APAVE, which specializes in collaborative robots, accompanied the thyssenkrupp TPM professionals during all key phases of the project. Finally, a year and a half of development work dispelled any safety concerns, allowing the cobot to be approved for use.

Decisive advantages: safety, speed and reducing the physical strain on colleagues

The cobot has been assisting with the series assembly of the smart since January 3, 2023, and has impressed everyone with its speed and precision. Gilles: "It doesn't matter which way round any module arrives. The cobot always calculates the correct coordinates with the help of a vision sensor, and it automatically fills the transmission with the required oil without spilling a single drop." 

So, the cobot does an excellent job not only from a sustainability point of view. The time-consuming and expensive process of cleaning the mounting plate and the floor is also a thing of the past. In addition, the colleagues on the production line can devote themselves to other tasks, and have to cope with considerably less physical strain: "Our colleagues are thrilled because the robot now does the unergonomic work for them," Gilles said.

The thyssenkrupp CoC collaborative robot offers two further decisive advantages compared with other robotic solutions: "When using normal cobots, it's not possible to exceed certain speed limits for safety reasons," Gilles explains, "whereas we can operate our cobot more safely at higher speeds with its Airskin suit. And absolutely safely: if the force sensor located at the front of the flange registers contact with any of our colleagues, the robot immediately returns to its starting point and reports that someone is in the way." And, while ordinary industrial robots take up a lot of valuable space with their elaborate protective systems, the Airskin cobot is much more frugal.

Competence Center for cobots

thyssenkrupp Automotive Systems has scored a magnificent success with this pilot project, which is likely to be followed by many more. The declared aim of the cobot specialists at the CoC in Forbach, France, is to strengthen cooperation with all areas of the corporate family, and to ensure an effective knowledge transfer. Gilles: "If any other departments at thyssenkrupp are interested, they are welcome to contact us to arrange workshops together on the subject of cobots. We're also looking forward to working with them on developing appropriate applications."