Vehicle drive chains are subject to a variety of demands, typically requiring major time and financial investments in order to meet requirements regarding driving performance, emissions, durability, and fuel consumption. To keep development cycles as short as possible, companies use computer and test bed simulations, as well as test drives. With test drives, actual driving data is generated and this is useful for providing a foundation for simulations. From a control engineering point of view, it can be extremely difficult to replicate measured driving cycles on a powertrain test bed. This is because different elements within the powertrain can have extended downtimes and are non-linear. The previously applied techniques for drawing on data measurements to control test beds took a great deal of time to set up parameters, and often this resulted in deviations in the test bed setup and thus unrealistic findings.
To solve this issue, Daimler, based in Stuttgart, asked representatives of powertrain development and the company’s powertrain testing facility to work with the Niederstotzingen-based Steinbeis Transfer Center (STC), Traffic Engineering.Simulation.Software, with the aim of developing a test bed control system for powertrain technology. Previously, Daimler had used simulation software called winEVA, which was also developed by the STC and worked well for generating collective load data.
To finally solve new issues, the experts selected a combination of “control” and “regulation.” For the test bed control part of the equation, real-time simulations of the drive chain are carried out using winEVA under testing conditions. Adjustment variables, gas pedal settings, and wheel rotation speeds can then be transmitted to the testing facility. Reactions on the test bed are then compared to the simulation model, and any differences between test bed behavior and the simulation model are used to make adjustments to this model.
This fundamental approach has been fine-tuned and updated many times over the years, such that it is even possible to use control technology to manage highly dynamic, purely electric drive systems, as well as 4x4 drivetrains involving complex four-wheel drive strategies.
The project partners have been honored with the Steinbeis Foundation Transfer Award – the Löhn Award – in recognition of the innovative and forward-thinking nature of the project and the manner in which the development partnership continues to build on the success of the collaboration.
Jakob Häckh & Prof. Dr.-Ing. Günter Willmerding
Steinbeis Transfer Center Traffic Engineering.Simulation.Software