Munich, 04 July 2024 – An engineering scientist who not only optimises the performance of almost all machine tools, but who also won an award for his short stories in the Baden-Württemberg state competition for German language and literature: The WGP (Scientific Society for Production Engineering) has chosen a very special winner this year in the person of Dr Christoph Hinze from the Institute for Control Engineering of Machine Tools and Manufacturing Units (ISW) at the University of Stuttgart. “The fact that Christoph Hinze has found his way from literature to engineering is a particular stroke of luck for us,” says WGP President Prof Michael Zäh. “His interdisciplinary interest, for example in mathematics, has brought great added value to his research. We need people with an interdisciplinary mindset for our increasingly transdisciplinary working groups.”
The results of Hinze’s research are impressive. Ten years ago, he was awarded the Günther Pritschow Prize for his bachelor’s thesis on continuous machine learning using artificial neural networks.”I was lucky with this topic and was able to publish two papers based on it,” is Hinze’s modest comment.After completing his Master’s degree with the grade “very good”, the young talent was “lucky” again with his first project funded by the German Research Foundation (DFG).
It involved the handling of flexible parts such as cables and ropes with robots, in particular fast and robust localisation using camera images and shape control. “This is a field of research that is on the rise, and only a few steps are still missing before the process can be used robustly,” says Hinze. In future, this could be used to automatically wire control cabinets or lay cable harnesses in the automotive industry, for example.
Machine tools become more dynamic
In the course of his dissertation, the 32-year-old finally found a way to move ball screw drives more dynamically and accurately thanks to model-based position control, thereby optimising the drives of almost all machine tools.
The key to the analysed sliding mode control lies in the degree of abstraction of the ball screw drive. “Until now, most control approaches in research have involved replacing the entire control system, which means that the force balance in the ball screw drive must be known very precisely,” explains Hinze. “With the new method, we only replace one part, the position controller. This makes it much easier to model the controlled system, as the rest of the control system already absorbs a large part of the uncertainties. At the same time, parameterisation has been simplified for industrial applications, which is comparable to the setting of the previously used controller.”
Thanks to the model-based position controller, errors in the guidance behaviour of the machine can be reduced by an average of 50 to 60%. The same applies to errors resulting from faults that occur during milling, for example. Overall, both have a major impact on the quality of the components.
The model-based position control can also be transferred to other drive systems that exhibit similar model behaviour. Examples of this include rack and pinion drives, which are used on very large machine tools, or drives in the joints of industrial robots, which are now to be demonstrated experimentally.
Modelling the production facilities of the future more precisely
Modelling is also the focus of the junior research group funded by the state of Baden-Württemberg within the Innovation Campus Mobility of the Future (ICM), which Hinze has headed since completing his doctorate. So-called grey box models are intended to help improve the path planning and control of machines with the help of machine learning models and thus, for example, enable more precise machining with machine tools or predict and check process errors before machining. The method utilises known model knowledge of machine dynamics and only the deviations are trained using machine learning. This allows simpler machine learning models to be used, which can also be executed on the control system in real time. Such deviations are caused, for example, by tolerances in production, but also by effects that can only be modelled analytically with a great deal of effort.
The project, which is funded by the Baden-Württemberg Ministry of Science, Research and the Arts, will run until the end of 2026, by which time the researchers at the Stuttgart institute and in collaboration with other research institutes aim to broaden the topic and transfer initial results to industry.
Giving back what he has received
Research really is “the thing” for the young scientist. “I was already attracted to the natural sciences at school,” says the engineer. “I was particularly interested in the STEM subjects, but I am especially fascinated by the mathematical abstraction of systems such as robots or machine tools: the fact that different effects are nevertheless similar in their equations.”
In addition to his research work, Hinze also took on numerous teaching assignments early on. Not only did he help organise lectures and tutorials, he also supervised over 20 student projects during his doctorate alone. “I benefited a lot from other students, colleagues and professors during my studies and my time as a doctoral student,” he says. “I would like to pass that on.” The students certainly like it. They appreciate his dedicated supervision and his motivating manner.
It’s important to take a step back
Hinze works a lot because it is his passion – and when it correlates with the working hours of his wife, who also works evenings and weekends. But it’s by no means everything. His year abroad in New Zealand opened his eyes to the fact that you can achieve good results without focussing solely on work. “It helps to take a step back every now and then,” says the award winner. “In New Zealand, people have internalised this lifestyle.” Hinze has found a way in this direction for himself in sport. In his free time, he sometimes cycles 150 km, runs half a marathon or swims a few kilometres. “It’s a contrasting programme to my WiMi work,” he laughs, “and it clears my head.” For his next research projects, presumably.
Download
Image 1: Presentation of the Otto Kienzle commemorative coin on 4 December 2024 in Chemnitz, (from left to right: WGP President Prof. Michael Zäh, Dr Christoph Hinze), source: TU Chemnitz / Katja Klöden
Image 2: Dr. Christoph Hinze, source: University of Stuttgart, ISW