Introduction

Purpose

The Hydraulics Library, or HL, is targeted to modeling of a hydraulic systems in a broad range of applications. Examples are automotive, aerospace, industrial equipment and construction equipment. The library can be used for component selection, dimensioning, system performance studies, virtual prototyping of system designs, transient response studies and support control system development and evaluation. The physical component model approach makes it easy to realize non-standard circuits. This library is compatible with other Modelon libraries and Modelica Standard Library.

Modeling and simulation

Many simulation tools are essentially user-interfaces for setting the parameters of fixed simulation models. This means that the actual equations that describe the model are impossible, or difficult, to modify by users. This Modelon library offers a different approach and provides much more flexibility. In combination with a simulation tool this Modelon library is a complete modeling and simulation tool. This is important to understand, since it implies that the working procedure is slightly different and contains some additional steps:

• Build models that describe the phenomena of interest,
• Tune the model parameters,
• Use the models to set up an experiment that exposes the phenomena of interest,
• Simulate the experiment,
• Analyze the results

This Modelon library contains a large set of pre-defined models and templates that makes most modeling tasks straightforward. For many standard tasks it is possible to use the library in the same way as a pure simulation tool, i.e. it is sufficient to choose the right model, define all parameters and start the simulation.

Flexibility with prudence

It is possible for users to modify and extend most of the models in the library, and also to complement the library with custom models. It is also possible to mix with model components from other libraries. This is one of the major benefits of describing models using a high-level modeling language like Modelica. Customization of models and components can be done either from the graphical user interface and diagram view, or, for advanced users, by typing Modelica source code. There is also great flexibility in setting up experiments and analyzing results. The flexibility implies great freedom for users to define models and experiments, but may also require more attention to details and understanding.

Modelon libraries

All Modelon libraries are compatible and can be combined to solve specific engineering design tasks. Two libraries of Modelon are of particular interest for the Hydraulics library: the Heat Exchanger library and the Liquid Cooling library. The Heat Exchanger library contains detailed models of heat exchangers and permits stacking. The Liquid Cooling library on the other hand is designed for modeling of coolant circuits. Please note that both these libraries can also be used as a stand alone solution.

The Hydraulics library is specifically designed to model the transient and steady-state behaviour of oil hydraulic systems. It is not recommended to use this library to model pneumatic systems by changing the medium properties. For these kind of systems it is recommended to use Pneumatics Library, a library of pneumatic components in Modelica.