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Project type: Explore Project

Certifiable Controller Synthesis for Cyber-Physical Systems

Summary

As cyber-physical systems (CPSs) are becoming ever more ubiquitous, many of them are considered safetycritical. We want to help CPS manufacturers and regulators with establishing high levels of trust in automatically synthesized control software for safety-critical CPSs. To this end, we propose to extend the technique of formal certification towards controller synthesis: controllers are synthesized together with a safety certificate that can be verified by highly trusted theorem provers.

Value Creation

From a distant view point, our project aims to increase confidence in safety-critical CPSs that interact with individuals and the society at large. This is the main motivation for applying formal methods to the construction of CPSs. However, our project aims to give a unique spin to this. By cleverly combining the existing methods of controller synthesis, (timed automata) mode checking, and interactive theorem proving via means of certificate extraction and checking, we aim to facilitate the construction of control software for CPSs that ticks all the boxes: high efficiency, a very high level of trust in the safety of the system, and the possibility to independently audit the software. Given that CPSs have already conquered every sector of life, with the bulk of the development still ahead of us, we believe such an approach could make an important contribution towards technology that benefits the people. 

Moreover, our approach aims to ease the interaction between the CPS industry and certification authorities. We believe it is an important duty of regulatory authorities to safeguard their citizens from failures of critical CPSs. Even so, regulation should not grind development to a halt. With our work, we hope to somewhat remedy this apparent conflict of interests. By providing a means to check the safety of synthesized controllers in a well-documented, reproducible, and efficient manner, we believe that the interaction between producers and certifying bodies could be sped up significantly, while increasing reliability at the same time. On top of that, controller synthesis has already been intensely studied and seems to be a rather mature technology from an academic perspective. However, it has barely set a foot into industrial applications. We are confident that formal certificate extraction and checking can be an important stepping stone to help controller synthesis make this jump. 

This project also contributes to the objective of DIREC to bring new academic partners together in the Danish eco-system. The two principal investigators have their specialization background in two different fields (certification theory and control theory) and have not collaborated before. Thus the project strengthens the collaboration between the two fields as well as the collaboration between the two research groups at AU and AAU. This creates the opportunity for the creation of new scientific results benefiting both research fields. 

Finally, we plan to generate tangible value for industry. There are many present-day use cases for control software of critical CPSs. During our project, we want to aid these use cases with controllers that tick all of the aforementioned “boxes”. This can be done by initiating several student projects and theses supporting theory development, tool implementation, and use case demonstration. The Problem Based Learning approach of Aalborg University facilitates this greatly. Furthermore, those students can use their experience
in future positions after graduating. 

Participants

Martijn Goorden

Postdoc

Aalborg University
Department of Computer Science

E: mgoorden@cs.aau.dk

Simon Wimmer

Postdoc

Aarhus University
Department of Computer Science

E: swimmer@cs.au.dk