SysML to SLIM transformation methodology

Abstract

: Identifying faults early on in the design phase drastically reduces the cost of fixing them and can even prevent the loss of a spacecraft. The Correctness, Modeling and Performance of Aerospace Systems (COMPASS) project created a toolset to approach the design of systems with a model-based angle, specifically critical on-board systems for the space domain. The COMPASS toolset requires an input model written in the high-level System-Level Integrated Modeling (SLIM) language. Systems engineers working with a Model-Based Systems Engineering (MBSE) approach commonly use a graphical modeling language to model systems on an architectural level. One of modeling languages most used for this purpose is Systems Modeling Language (SysML). For optimal use of the COMPASS toolset in an MBSE design project, a smooth transition between SysML and SLIM is desired. There is currently a gap between these two languages is present. The challenge lays in the fact that systems engineers using a graphical modeling language are not software engineers, which limits the ability to model the architectural SysML model in SLIM. This thesis presents a new developed methodology, the SysML to SLIM Transformation Methodology (SSTM), to develop a space SysML model which is able to automatically transform a SysML model into a SLIM model, ready to be imported by the COMPASS toolset. This allows a systems engineer without software engineering knowledge to model in a familiar modeling environment, but adds the ability to directly run tests on the model using the COMPASS toolset thus giving valuable insight into the behavior, limitations and possible errors of the system under development. Ultimately reducing development time and cost. A methodology based on the Object-Oriented Systems Engineering Method (OOSEM) method is created that introduces a set of custom stereotypes. Modeling with these stereotypes allow the transformation tool to automatically transform the SysML model into a SLIM model. The open-source, Eclipse-based modeling environment, Papyrus is used to model the SysML model. A profile with the required stereotypes is developed which can be imported and used in Papyrus projects. The transformation tool, written in Java, has a simple Graphical User Interface (GUI) to load the SysML model and save it as a SLIM model. Two experiments were executed and are presented in this thesis. Verifying the SSTM methodology and transformation tool was the main focus point of the first experiment in which a battery-sensor system was modeled. A second experiment was performed modeling an Attitude Determination and Control System (ADCS) case study to test the possibilities and limitations of modeling a complex space related system and identifying improvement points for the SSTM methodology. The first experiment successfully verified that using the SSTM methodology a SysML model can be developed without significantly more effort than to develop any other SysML model. It also verified that the tool successfully transformed the SysML model into a correct SLIM model that can be used in the COMPASS toolset. The second experiment, modeling an ADCS case study, showed that a simple space system can successfully be developed with the SSTM methodology. The case study also identified important improvement points for the SSTM methodology to model complex space systems. The experiments performed show that the SSTM methodology and transformation tool together bridge the gap between SysML and SLIM models and can be analyzed in the COMPASS toolset. This can be performed without significantly more modeling effort and in-depth programming knowledge. At this stage the SSTM methodology and transformation tool are ready to be used on component-based systems with event-based error models. Improvements in the SSTM methodology are proposed. The improvements will increase the maturity of the SSTM methodology and allow the modeler to model complex space systems SysML models with more ease and with less programming knowledge.