In the first four parts of this series, we have focused on the SysML modeling part of the systems engineering effort. While general-purpose modeling serves many purposes, some parts of design and analysis are best done with more specialized tools. The ability to keep multiple models consistent is the objective of Model-Based Engineering (MBE) and in this part, we will use the Syndeia MBE platform from Intercax to transform part of the SysML model into a Simulink model (The MathWorks, Inc.)
In this series of blog posts, we have described some preliminary results for such an approach, showing sample diagrams from several different SysML modeling tools (MagicDraw from No Magic Inc, IBM Rational Rhapsody, and Enterprise Architect from Sparx Systems). These models are available for download below.
Connecting RCS Models
As stated in the introduction, the ability to transform the architectural model created above into models in other tools is a key part of this approach. Specialized tools for simulation or even operation of the RCS will continue to play critical roles in the engineering process. To be most useful, these models must be able to be compared and updated so that differences in models can be recognized and resolved.
Figure 1 Railway Siding Example, internal block diagram showing track connectivity
Figure 1 shows the SysML Siding model from Part 3. In Figure 2, we show a Simulink model created from it using the Syndeia MBSE platform from Intercax. Many of the Simulink blocks have an internal structure that is also carried over, as shown, for example, in Figure 3 for the ControlPoint_3Way block.
Figure 2 Simulink model of Siding example
Figure 3 Simulink model of ControlPoint_3Way
This is offered only as an example of the kinds of model transform possible. Simulink is probably not the best choice for simulating an RCS. For example, bidirectional flows cannot be easily simulated. But this is only one of many possible transformations. Discrete event and network simulation tools, budgeting software and many others could draw upon the structure and parametric values in the SysML architecture model and process them in unique ways.
We have offered these examples primarily to inspire ideas in systems engineers in railway and other transportation domains looking to apply the principles of MBSE to their work. Further refinements could add the trains to the model, perhaps as item properties, and parametrics for analysis. Libraries of requirements managed in a configuration-managed repository could be connected to the model, with the opportunity for test case management and verification. The RCS software could be modeled as well as the hardware.
Contact Intercax for more information at email@example.com.
Models to download:
- For MagicDraw: RailwayControlSystems.mdzip
- For Rhapsody: RailwayControlSystems.rpy
- Railway Control System Modeling | Part 1
- Railway Control System Modeling | Part 2
- Railway Control System Modeling | Part 3
- Railway Control System Modeling | Part 4
- Railway Control System Modeling | Part 5 (this post)