Parameterized Verification of Algorithms for Oblivious Robots on a Ring

We study verification problems for autonomous swarms of mobile robots that self-organize and cooperate to solve global objectives. In particular, we focus in this paper on the model proposed by Suzuki and Yamashita of anonymous robots evolving in a discrete space with a finite number of locations (here, a ring). A large number of algorithms have been proposed working for rings whose size is not a priori fixed and can be hence considered as a parameter. Handmade correctness proofs of these algorithms have been shown to be error-prone, and recent attention had been given to the application of formal methods to automatically prove those. Our work is the first to study the verification problem of such algorithms in the parameter-ized case. We show that safety and reachability problems are undecidable for robots evolving asynchronously. On the positive side, we show that safety properties are decidable in the synchronous case, as well as in the asynchronous case for a particular class of algorithms. Several properties on the protocol can be decided as well. Decision procedures rely on an encoding in Presburger arithmetics formulae that can be verified by an SMT-solver. Feasibility of our approach is demonstrated by the encoding of several case studies

Formal verification of Mobile Robot Protocols

Mobile robot networks emerged in the past few years as a promising distributed computing model. Existing work in the literature typically ensures the correctness of mobile robot protocols via \emph{ad hoc} handwritten proofs, which, in the case of asynchronous execution models, are both cumbersome and error-prone. In this paper, we propose the first formal model and general verification (by model-checking) methodology for mobile robot protocols operating in a discrete space (that is, the set of possible robot positions is finite). Our contribution is threefold. First, we formally model using synchronized automata a network of mobile robots operating under various synchrony (or asynchrony) assumptions. Then, we use this formal model as input model for the DiVinE model-checker and prove the equivalence of the two models. Third, we verify using DiVinE two known protocols for variants of the ring exploration in an asynchronous setting (exploration with stop and perpetual exclusive exploration). The exploration with stop we verify was manually proved correct only when the number of robots is $k>17$, and $n$ (the ring size) and $k$ are co-prime. As the necessity of this bound was not proved in the original paper, our methodology demonstrates that for several instances of $k$ and $n$ \emph{not covered} in the original paper, the algorithm remains correct. In the case of the perpetual exclusive exploration protocol, our methodology exhibits a counter-example in the completely asynchronous setting where safety is violated, which is used to correct the original protocol

Guard Automata for the Verification of Safety and Liveness of Distributed Algorithms

Distributed algorithms typically run over arbitrary many processes and may involve unboundedly many rounds, making the automated verification of their correctness challenging. Building on domain theory, we introduce a framework that abstracts infinite-state distributed systems that represent distributed algorithms into finite-state guard automata. The soundness of the approach corresponds to the Scott-continuity of the abstraction, which relies on the assumption that the distributed algorithms are layered. Guard automata thus enable the verification of safety and liveness properties of distributed algorithms

LIPIcs, Volume 248, ISAAC 2022, Complete Volume

LIPIcs, Volume 248, ISAAC 2022, Complete Volum

NASA space station automation: AI-based technology review

Research and Development projects in automation for the Space Station are discussed. Artificial Intelligence (AI) based automation technologies are planned to enhance crew safety through reduced need for EVA, increase crew productivity through the reduction of routine operations, increase space station autonomy, and augment space station capability through the use of teleoperation and robotics. AI technology will also be developed for the servicing of satellites at the Space Station, system monitoring and diagnosis, space manufacturing, and the assembly of large space structures

Guard Automata for the Verification of Safety and Liveness of Distributed Algorithms (long version)

Distributed algorithms typically run over arbitrary many processes and may involve unboundedly many rounds, making the automated verification of their correctness challenging. Building on domain theory, we introduce a framework that abstracts infinite-state distributed systems that represent distributed algorithms into finite-state guard automata. The soundness of the approach corresponds to the Scott-continuity of the abstraction, which relies on the assumption that the distributed algorithms are layered. Guard automata thus enable the verification of safety and liveness properties of distributed algorithms