Simulation of Fluid Power Systems in Consideration of Uncertainties

Abstract

This paper presents the fundamental interrelation of uncertainty in the context of the modeling and simulation process of fluid power systems. Building up a simulation model means to represent a real system and its dynamic behavior in an experimental model. This process generally requires a model simplification. Additionally, in an early stage of product development, a certain lack of knowledge about a system is to be assumed. These so called epistemic uncertainties lead to a deviation of the simulated system’s behavior from the real one. One possibility to consider such uncertainties in simulation is by using the approach of fuzzy arithmetic. This approach allows substituting crisp parameter values through fuzzy intervals. This way, uncertainty-sensitive simulation results can be obtained and the reliability of simulation can be significantly increased. Especially for the simulation of fluid power systems with lumped parameters, a trade-off between simulation performance and the level of detail of the model has often to be accepted. The assumption of uncertainties in fluid power simulation shows the potential of creating simplified simulation models, which at the same time promise to have a high conformance to the real system behavior. Using the fuzzy arithmetic approach under application of the transformation method by Hanss, the potential for fluid power system simulation in consideration of epistemic uncertainties is explained and evaluated. Therefore, a simulation model is tested as an example application using different degrees of parameter fuzzification.