Software for Fluid Power Technology

From Editor

What is DSHplus?

Based on graphics, DSHplus focuses on the description of the system on the functioning unit “component part” as the central element of the modelling conception. Libraries containing hydraulic and pneumatic, as well as electric, control and mechanical elements, are available for that purpose. The ensuing circuit analogy allows an easy and comfortable design of the simulation model and ensures that the user becomes familiar very quickly with DSHplus (Fig. 1).

Fig. 1: DSHplus working environment

The uncomplicated way of setting the parameters of the component parts is an essential precondition for the acceptance of the simulation in industrial practice. Hence, the catalogue data of the manufacturers constitute the basis for the modelling of the component parts in DSHplus. In addition, the open mathematical description of the system as C++ Source Code allows the user to include his own description of the component part and makes it possible to interface with other simulation tools.

The implementation of DSHplus on PCs means the program can be used without additional investments in hardware or software at almost every modern design working place.

Working with DSHplus

In order to draw up a new simulation model in DSHplus, the user chooses the required elements for setting up the system from the libraries and drags them onto the worksheet. Linking the connections with the mouse connects the individual elements. Without further assistance, DSHplus inserts the correct connection type (hydraulic, pneumatic, mechanical, signal). This approach is very intuitive and allows the novice user to get started very quickly.

The parameters of the simulation model are set one component part after the other. Verified data sets of one component part can be saved in a database and loaded again. Thus, the user is able to record parameter sets of components from different suppliers and of different sizes and to refer to them in future projects.

The simulation starts once the required parameters of the dynamic simulation are entered. In order to control the simulation, two different online-output modes are provided with DSHplus; one is the dynamic numerical display of the calculated values, and the other is the graphical display of selected variables (pressures, strokes, signal processes etc.) in one or several output windows.

DSHplus is designed for the simulation of fluid-technical systems including adjoining technical domains. The term “system” stands for complex plants as well as for fluid power components. The libraries offer components with various complexities for the different systems. The bandwidth comprises e.g. simple static pressure relieve valves with a characteristic for the flow up to a detailed hydro-mechanical valve with a pilot stage (Fig. 2).

Fig. 2: DSHplus application 1

Numerous examples of industrial and automotive applications of DSHplus prove the flexibility and the versatility of the software. It is utilized e.g. at the following projects: roller adjustment in a cold-rolling plant, servo-hydraulic ingot mould oscillation drive, optimization of the overall control cycle of a forging press, simulation of active suspension systems, investigation of hydraulic actuation of a variable camshaft, examination of the oscillation characteristics of the pipes and hoses of a power steering unit (Fig. 3).

Fig. 3: DSHplus application 2

DSHplus Simulation Tool Chain

By means of the DSHplus-STC the system developer can concentrate in full and completely on the solution of the technical problem. For this the full functionality of the DSHplus analysis and documentation tools are available so that the system developer can work autonomously in the boundaries of his technical scope up to the verified sub-system (Fig. 4).

Fig. 4: DSHplus simulation tool chain

Using the different interfaces of the DSHplus-STC at any time an integration of the work that has been done on the fluid power sub-system into the overall project scope is possible. As a result, project coordination can implement a reasonable division of labour, what guarantees an effective, swift and cost-optimized development.

After the system has been set-up autonomously, the DSHplus model is integrated into the overall development by means of the DSHplus-Co-Simulation-Interface. However, if the systems exceed a certain complexity or the individual sub-systems are configured completely, DSHplus-STC offers the export of the DSHplus simulation model as system of equations or as a module computing itself (DSHplus-Standalone-Module).

Because the DSHplus-STC interface functions for co-simulation and the “embedded mode” of the stand-alone modules are standardized one and the same DSHplus simulation model can be linked to different target simulation environments without any change in the DSHplus model (Fig. 5).

Fig. 5: DSHplus simulation tool chain

A major benefit of this DSHplus-STC functionality is that the verified fluid power sub-systems can be distributed to colleagues or project partners together with the simulation model in which they are integrated. There is no need to have a copy of DSHplus on the target machine; only a runtime license for each computer using the export result has to be acquired.

DSHplus for HIL-Applications

Fig. 6: DSHplus for HIL-applications

Using the DSHplus-HIL-Box a fluid power engineer it is able to develop and test complex control concepts directly on the target control hardware even if no mechanical system hardware is available yet.

Benefits of the coupling of hardware controller with a DSHplus simulation model are the possibility to determine the initial controller gains for the startup of the system beforehand, to safely test critical operation conditions, and to perform failure analysis.

RK HM