Ensure: Towards Reliable Control of Cyber-Physical Systems Under Uncertainty

• Published in: IEEE transactions on reliability 2023-03, Vol.72 (1), p.289-301
• Main Authors: Yang, Wenhua, Xu, Chang, Pan, Minxue, Zhou, Yu, Huang, Zhiqiu
• Format: Article
• Language: English
• Subjects: Actuators; Control design; Cyber-physical systems; Cyber-physical systems (CPS); Markov processes; partially observable Markov decision processes (POMDPs); Rocks; Sensors; Software; Uncertainty
• ISSN: 0018-9529; 1558-1721
• DOI: 10.1109/TR.2022.3167116

Cyber-physical systems (CPSs) are complex ensembles of physical and cyber components that cooperate to offer dynamic and adaptive functionalities. Uncertainty can arise from a plethora of sources in the entangled components, ranging from the unreliable perception, the nondeterministic action effects, to even the changes in the environment. Existing controlling approaches, such as those using Markov decision process, have limited ability in handling uncertainty. To address the challenge, in this article, we novelly propose using partially observable Markov decision processes (POMDPs) to model CPS under uncertainty and show that common types of uncertainties can be modeled by partial observations and nondeterministic actions over probabilistic distributions. With POMDPs, strategies that can optimally control CPS are synthesized. We further propose a strategywise verification method, which resolves the difficult problem of verifying the entire POMDP, to offer reliable controlling strategies. Experiments on two representative cases of CPS show promising results compared with existing approaches.