A modeling architecture for the orchestration of service components in factory automation

Service-Oriented Architecture (SOA) is a paradigm for software development that has been increasingly adopted for factory automation. In SOA, services are independently developed and a central engine orchestrates their functional behavior according to the process workflow. If on one hand this orchestration is required to maximize performance and productivity, i.e., the software is required to be maximally permissive, on the other hand, implementing a service orchestrator is a creative task which cannot be totally automated. Furthermore, industrial processes tend to be very large, making it difficult to empirically provide in-advance quality guarantees for industrial SOA-based applications. In this paper, we show how maximally permissive and deadlock-free service orchestrators can be implemented. We propose a model for each activity that compose a SOA programming language. Then, we show how pieces of a workflow can be individually represented by combining activity models. Afterwards, we specify the logical behavior of the workflow in order to organize those pieces and reproduce the orchestration effect. By using controllability concepts, we finally compute from the orchestrator a version of it that formally provides certain quality guarantees. Examples illustrate the approach.