On the functional safety of a complex technical control system with digital twins

The Aim of this paper is to evaluate the advantages of digital twin technology as compared with the conventional approaches to the design of a vital two-channel system.Methods. The system is described with a Markovian model. This model allows defining the quantitative safety characteristics if the system is affected by right-side failures.Results. The system’s primary quantitative safety indicators were identified as the mean time to wrong-side failure and mean time to right-side failure along with the quantitative relations of the prime and additional costs for a batch of products.Conclusion. Transforming the initial item into a system with digital twins allows significantly reducing the rate of wrong-side failures. This effect may be obtained not only with the use of digital twins, but also as the result of the system transitioning into the state of right-side failure in each event of discrepancy betwin the initial item and/or the digital twins. It has been established that the mean time to right-side failure under such conditions is not less than the mean time to failure of the initial item. That means that highly efficient measures for safety improvement allow maintaining the system dependability at a level not lower than that of the initial item. The introduction of digital twins into a system is a new, not yet tested way of ensuring system safety. The decision on the benefits of additional costs is taken by the customer and system developer together. At the same time, it must be taken into consideration that in case of large batches of manufactured technical systems, the effect of additional costs is reduced and the effect of significantly improved safety is maintained.