In the framework of the European Space Agency’s Networking/Partnering Initiative (NPI) a PhD research project was organized by ESA and the Embedded Systems Unit of FBK on the topic of model-based tools to support formal design of fault management architectures. The work was performed by the PhD student Benjamin Bittner, under supervision of Alessandro Cimatti and Marco Bozzano on FBK side and Marcel Verhoef on ESA side. The project also included a 10 month reserach stay at the ESA ESTEC centre in Noordwijk (The Netherlands), where Benjamin developed several case studies on an actual satellite project. The dissertation was successfully defended on 15/12/2016.
The research builds on the results of COMPASS and its follow‐up projects AUTOGEF and FAME, and pushes the state‐of‐the‐art in timed failure propagation analysis and diagnosability analysis with formal verification tools.
The first line of work is on Timed Failure Propagation Graphs (TFPGs), which represent possible sequences of faults and their consequences (including triggering of potential monitors), integrated with information on propagation delays and mode constraints. Several formal techniques based on model‐checking have been developed to validate and also automatically generate TFPGs with respect to a system model of higher complexity.
The second line of work covers diagnosability analysis, which requires values observed by FDIR to carry enough information to allow diagnosis of faults or other anomalies. It is especially important when failure propagation analysis doesn’t give enough insights on how to detect and precisely localize faults; diagnosability checks whether diagnosis is possible at all. Algorithms are developed to verify diagnosability under a given set of observables, possibly under a constrained operational context. The techniques are also extended to automatically select subsets of the observables that optimize a given cost function.
Experimental evaluation shows the feasibility of the developed techniques. Several case studies on an ESA mission under development show the high potential of the techniques in a project setting.
- European Space Agency (ESTEC, Section for Software Engineering)
- Fondazione Bruno Kessler (Embedded Systems Unit)