Blockchain-based cloud controllers for reliable networked control systems

Networked control systems are critical in industrial applications but remain vulnerable to controller failures, which can destabilize operations. Blockchain technology offers a decentralized solution to enhance reliability. While blockchain technologies have been mainly used in financial systems (such as cryptocurrencies) so far, they are now being used in an increasing number of applications (such as logistics, power grids, or the Internet of Things) due to their powerful features and advantages. In this article, the use of blockchains is proposed and explored to deploy decentralized and reliable controllers. A blockchain-based controller architecture is presented to provide controllers that are permanently available, open accessible, and open source. Time to transaction finality and cost for transactions are analyzed in different blockchain networks, thus identifying their suitability. Our analysis reveals that blockchain networks can potentially be applied in slow processes with big enough time constants. Moreover, we propose the integration of event-based control to reduce transaction costs, thereby enhancing the viability of blockchain technologies in networked control systems. To demonstrate the practical application and cost efficiency of our approach, we present a case study focusing on a greenhouse climate control system. Results show that feasible blockchain networks – those compatible with sampling period constraints – consistently reduce control costs. For instance, on Fantom blockchain, event-based control achieved a 27.73-fold reduction in average control costs across six system variables over the eight-day operation period.