The assistant that lives in the tool – Ensuring quality in assembly

Premium add-on entertainment package for the following two vehicles, electric windows in the front doors only, the remaining car bodies with an automatically opening trunk, the next four with all electric controls as standard and, and, and.... This is more or less the reality on an assembly line focused on personalized customer equipment. Working on this kind of production line means constantly having to adapt to new screw profiles to ensure they are executed properly and fully. Using a solution developed by the Fraunhofer Institute for Integrated Circuits IIS, the BMW Group in Regensburg is now giving their production assemblers digital assistants directly on their tools. The case in point: hand-guided electric screwdrivers. For every assignment, the tool tells its operator whether all screwing procedures for a given job were properly carried out. Done! Then the next set of instructions arrives, displayed on a communication box measuring only a few centimeters. The intelligent software developed by Fraunhofer IIS analyzes the screwing direction, number of maneuvers and proper movement in real time and notifies the operator of the next step.

Mr. Seitz, how did you hit upon the idea of using a sensor fusion process to support work processes in production?

Industrie 4.0 in production is all about linking all kinds of data and evaluating it intelligently and quickly. When it comes to complex and real-time-enabled applications, a single technology is generally not going to be enough. It’s therefore necessary to exploit the strengths of a number of technologies and adapt them to a variety of challenges using intelligent algorithms. We began by refining accuracy by expanding the conventional tracking process with additional technology common to vehicle and pedestrian navigation. The next step was to detect small-scale movement sequences, such as of the hand, using hand-guided tools. We then presented the first prototype in collaboration with a tool manufacturer at CeBIT 2015.

What were the steps that followed once you entered development?

After these initial prototype developments – which still assumed the possible integration of the technology directly in the tool, foregoing an additional infrastructure – the idea of an universal “network box” began to crystalize.

Mr. Röske, how did the BMW Group hear about the project?

Point of contact for the initial conversations was the technology presentation, focusing on localization and communications technology, which Fraunhofer IIS made at a number of trade fairs in 2016. The BMW Group also held internal workshops with a view to finding a smart solution for wireless connection and assisting the hand-guided tools we use in production. My approach was that if a smartphone has the sensor technology to count steps, shouldn’t it be possible to use similar sensor technology for screw processes? What struck a chord here at BMW was the idea of a sensor fusion process for tool tracking – which would work with low-cost sensor technology and our existing Wi-Fi infrastructure – coupled with reliable analysis via Fraunhofer software.

Mr. Seitz, could you explain how your current installation is set up?

Gladly. In a sensor fusion process, measurements from gyroscope, accelerometer and magnetometer mounted on the electric screwdriver are combined together and characterized in real time. This tracking information is reconciled with existing parameters. If the values coincide, the production employee can be directly informed on-site via an LED display that all screw connections were properly executed. We are currently using this to check that all screws have been tightened correctly.

Mr. Röske, what are the next steps as you move towards production?

Our system’s prototype is currently undergoing testing on one of our production lines in our Regensburg factory. We’re doing this because it is also important to us that wherever machines don’t or can’t take on high-precision tasks, we give employees in digital production as much support as possible also through digital assistance systems.

This test phase serves to precisely analyze, together with our production employees, which figures must be used for quality assurance. Our goal is to continue to expand the system and, together with Fraunhofer IIS, carry it over into a product for additional production lines.”

Mr. Seitz, as a Fraunhofer scientist working in applied research, how could existing technology be used to take this idea further?

A localization system could easily be combined with the tool tracking system. For instance, the specific screw hole or screw connection could be allocated to every workpiece. Furthermore, certain processes can be documented as needed and coordinated by digital assistants for timely optimizations or adjustments.