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2017 17th International Conference on Application of Concurrency to System Design (ACSD) (2017)
Zaragoza, Spain
June 25, 2017 to June 30, 2017
ISBN: 978-1-5386-2867-6
pp: 49-58
ABSTRACT
We present Component-Based Simplex Architecture (CBSA), a new framework for assuring the runtime safety of component-based cyber-physical systems (CPSs). CBSA integrates Assume-Guarantee (A-G) reasoning with the core principles of the Simplex control architecture to allow component-based CPSs to run advanced, uncertified controllers while still providing runtime assurance that A-G contracts and global properties are satisfied. In CBSA, multiple Simplex instances, which can be composed in a nested, serial or parallel manner, coordinate to assure system-wide properties. Combining A-G reasoning and the Simplex architecture is a challenging problem that yields significant benefits. By utilizing A-G contracts, we are able to compositionally determine the switching logic for CBSAs, thereby alleviating the state explosion encountered by other approaches. Another benefit is that we can use A-G proof rules to decompose the proof of system-wide safety assurance into sub-proofs corresponding to the component-based structure of the system architecture. We also introduce the notion of coordinated switching between Simplex instances, a key component of our compositional approach to reasoning about CBSA switching logic. We illustrate our framework with a component-based control system for a ground rover. We formally prove that the CBSA for this system guarantees energy safety (the rover never runs out of power), and collision freedom (the rover never collides with a stationary obstacle). We also consider a CBSA for the rover that guarantees mission completion: all target destinations visited within a prescribed amount of time.
INDEX TERMS
collision avoidance, control engineering computing, large-scale systems, mobile robots, object-oriented programming, program verification, software architecture, theorem proving
CITATION

D. Phan et al., "A Component-Based Simplex Architecture for High-Assurance Cyber-Physical Systems," 2017 17th International Conference on Application of Concurrency to System Design (ACSD), Zaragoza, Spain, 2017, pp. 49-58.
doi:10.1109/ACSD.2017.23
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