The mechatronic systems of tomorrow have to meet high expectations: They have to interact with their environment and adapt to it autonomously, flexibly master unexpected situations and anticipate future events. At the same time, they have to stay user-friendly, be able to react to the increasing complexity of the overall system and, first and foremost, be interconnected more and in a smarter way. This is one of the core research areas of the Fraunhofer Institute for Mechatronic System Design (IEM), located at the Paderborn technology center Zukunftsmeile Fuerstenallee. The institute offers companies expert support in developing intelligent mechatronics in the context of industry 4.0. The extensive expertise of Fraunhofer IEM in methods and tools for developing mechatronic systems is strengthened by the interdisciplinary collaborations with the Heinz Nixdorf Institute and the University of Paderborn. As part of the Fraunhofer-Gesellschaft, Europe’s largest organization for practice-oriented research, IEM has international contacts and supports international collaboration.
Virtual validation of the test bench environment.
Currently, Fraunhofer IEM in Paderborn is working on the model-based design of a test bench for developing and testing steering systems. By virtualizing the test bench, the institute can verify its setup and environment in advance.
Since steering systems are safety-critical systems in a vehicle, car manufacturers invest great effort in intensive tests of the related functions and characteristics. The virtual test bench of Fraunhofer IEM is designed to be used primarily for analyzing the transient response and disturbance behavior of different steering concepts. It is also planned to test and optimize different control methods for hydraulic excitation units in this environment.
First, while developing an initial concept for the test bench environment, a system of coherent partial models is defined that describes the entire test bench environment. Predefined use scenarios are used to derive requirements for the test bench, which are documented in a requirements list that can later be checked automatically. To validate the test bench concept early in the development process, the environment to be developed is specified with a model-based approach according to the operating structure, and the vehicle models needed for information processing are created. In the next step, model-in-the-loop (MiL) tests are performed with the help of the dSPACE tool chain. These tests let the researchers virtually validate the correct behavior of the test bench environment together with the evaluation of the vehicle model. The PC-based simulation platform dSPACE VEOS makes it possible to perform simulations without additional hardware to verify, validate and test the control for the test bench environment in an early development phase. This means a complete test bench can be put into operation even though it does not physically exist yet. In addition, HiL tests, scenarios and processes can be prepared and frontloaded to the PC. The result is a virtually validated model of the test bench environment, including the necessary controls and a test automation that is already implemented.
As the project progresses, the defined solution concepts will be replaced by specific solution elements, which will further specify the test bench environment virtually. To set up the real system afterwards, the test bench components that were created virtually will be replaced by real elements. The test bench control will be reused and extended by hardware-specific interfaces so it can be integrated in the test bench environment.
Dipl.-Ing. Alexander Gense is a senior expert in the Control Engineering department at the Fraunhofer Institute for Mechatronic System Design (IEM).
Stefan Schütz is a research associate in the Control Engineering department at the Fraunhofer Institue for Mechatronic System Design (IEM).