Alternative controls for soft real-time industrial control services in case of broken cloud links

Currently, cloud computing offers flexible, dynamic and cost effective computing outsourcing, but it limits these economic and operational benefits to non real-time and non safety-critical systems. This is because of the lack of alternative control, supported by current cloud infrastructures, in case of a broken cloud link. While steps have been taken in using cloud infrastructures for soft real-time systems in industrial operations, such as using a virtualised PLC from a cloud, a gap still exists in appropriate handling of operations in the case of a broken cloud link. This paper proposes a new hybrid approach for providing control services from the cloud that can handle the essential communication locally in case of a broken cloud link. The proposed approach is also tested with two different scenarios for an initial evaluation.