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P&T Research

Function test well before applying the first weld seam

For more than one year, Plasser & Theurer has been using the Hardware in the Loop method. For the time being, it primarily serves to test and optimise the function of machine control units. The fascinating thing about it is that these tests can take place as soon as design is completed – before the machine is built.

Simulation technologies are indispensable for modern-day machine building. They reduce costs by emulating otherwise laborious test and development assemblies in a virtual manner. They save time because these tests can be carried out irrespective of the production progress. In addition, they enhance quality because the results can be used directly for improving the design of the machine.

The Hardware in the Loop (HiL) method is used to simulate the actual environment of a component by digital means. Harald Daxberger, HiL expert at Plasser & Theurer: “In our case, it is always a specific machine we model. This simulation is then used to connect the actual control device to test functioning.”

Testing functions efficiently

Currently, Plasser & Theurer mainly applies this procedure to testing machine controllers. The major advantage is that testing can begin directly after completion of design and software development rather than during commissioning of the machine. This leaves enough time to optimise the configuration of functions. In addition, commissioning becomes more efficient as system issues can be identified and resolved early on.

Calculating ballast flows in advance

Another strength of the method is that one can prove the proper functioning of a machine before its completion. This option is particularly helpful when building large customised machines and has already been used in one specific case. The purchaser of a track renewal and ballast cleaning machine wanted to know whether the automatic system provided to prevent overfilling of the ballast hoppers would work flawlessly. A simulation model had to be set up to answer this question. The ballast flows and the interaction of the conveyors were simulated. The model was then connected to the actual control unit which regulates both the speed of conveyors and their position. With the help of this test arrangement, we were able to prove that the automatic system would work as intended.  

Other applications in preparation

In addition to optimising control units, the HiL method can be used for other purposes as well. Harald Daxberger: “It is certainly feasible that we can use this tool for remedying any faults in operation. For this purpose, we would simulate the entire situation including its environment on the computer and therefore not need to go to the construction site.”

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Alexander Greindl
Head of Control Technology at Plasser & Theurer

For optimising control units, the HiL method is a huge step forward. Long before the commissioning, it enables us to determine whether the designed functions work properly in practice.