Simulating a Pneumatics Network using the DLR ThermoFluidStream Library

Abstract

Modeling and simulation of pneumatics networks is still a challenging task, plagued by initialization problems even in sophisticated environments such as the Modelica Fluid Library. The recently proposed DLR ThermoFluid Stream Library uses a promising new approach to cope with such problems. Therefore, it should be a convenient basis for a more specialized pneumatics library. The essential concepts and components of such a library are presented, with a special focus on the notorious tee branch components. Their dynamic behaviour is very complex, since it couples the effects of dynamic pressure changes and friction losses, and often leads to stability problems. Results of systematic tests as well as more realistic models are discussed. They show that even though some problems with stability remain in special examples, the new library generally allows for the simulation of pneumatics networks using realistic tee branch models, which are more accurate than previous implementations.