The new platform library provides mechanical and plant engineering with a very high-performance simulation tool for virtually configuring, testing and commissioning entire plants, including the control system (PLC). The platform includes simulation libraries with highly specialized, technology-specific simulation solutions that can be expanded as needed. The basis of the virtual control systems is software-in-the-loop simulation. The original control algorithms of the PLC are used. The simulation time can be freely controlled and is thus no longer coupled to the hardware clock. The platform has standardized integration interfaces to include the various control models in the overall simulation of a machine.
Hardware-in-the-loop simulation - state of the art
In recent years, the increasing complexity of machines and plants had led more and more to programming the control software (PLC) only on the real plant - i.e. during commissioning. With the development of digital twins and hardware-in-the-loop simulation, it has been possible to shift this process back to the engineering phase: In this process, the virtual components, assemblies and systems map their real-life models one-to-one, from the parameters to the interfaces to the control behavior. The control hardware is connected to the digital twin via the industrial real-time fieldbus, which simulates the behavior of the fieldbus components in such a way that there is no difference to the behavior of real fieldbus components. Practical experience confirms that these digital test simulations significantly accelerate development processes and commissioning, contribute to quality improvement and reduce costs. In order to exploit synergy effects within the industry, ISG has also set up a simulation platform with virtual component libraries that machine and plant manufacturers as well as component suppliers use equally. It already includes extensive component libraries, for example for robot systems, drive technology, conveyor technology, gripping systems and sensor technology, and will be successively expanded.
Platform library for linking virtual controllers
Now the engineers have gone one step further and built up a platform library. It contains simulation solutions - tools and models - as well as standardized interfaces to common control systems. The idea behind it: An online platform for simulation models allows machine builders to simulate the hardware and software components of a plant end-to-end without breaking the system. The virtual controllers come from partners, for example Numerik 1 from Siemens. Again, this is a modularly structured library that maps a wide range of application scenarios and continuously grows with them.
Multicore simulation in real time
Real-time computation and real-time synchronization is made possible by model partitioning: The building block-based system model is decomposed into different sub-models - across component boundaries. This can be done automatically by the system or manually by the user. Several computational kernels work in parallel and make it possible to couple a wide variety of simulation disciplines. These include the description of the process, the simulation of machine behavior, for example in terms of logic, kinematics and dynamics, as well as the behavioral simulation of industrial control components including their sensors and actuators. The modeling environment shows the user how the overall model is distributed across the individual computational cores and allows him to make adjustments and reconfigurations. Mechanisms are also available to check the partitioning.
Virtual controls thanks to software-in-the-loop method
Analogous to the work with digital twins, software-in-the-loop simulation is used to design and test the control system in virtual form. Such a simulation can be performed even before the control hardware is available. The IT department is thus even more flexible in terms of time and can start work on the control components at a very early stage. The software-in-the-loop method is also much more cost-effective as a result of the non-existent simulation environment.
It makes sense to use the same model for the subsequent hardware simulation to save additional effort, create a seamless transition between the two test runs and make them comparable.
Advantages of the modular platform library
- Designers can perform extensive test runs with different virtual controllers to find the optimal control system for a given plant with relatively little effort and in a short time.
- The platform is multicore capable. By distributing the computing processes over several cores, they can be run in parallel. This increases computing performance considerably and enables co-simulation in real time.
- As an online platform, the system is simultaneously available to end customers and hardware suppliers. They use the digital twins together and thus avoid unnecessary additional work.
- An entire plant can now be continuously simulated and virtually commissioned - from the individual component to the control system.
Author: Dr. Christian Scheifele, Head of R&D Simulation Technology, ISG Industrielle Steuerungstechnik GmbH