This article focuses on operation sequences engineering and preparation for complex and critical systems. The main objective is to safely operate some action sequences on the process devices (mainly actuators), according to safety requirements specifications. Based on a process formal model using communicating automata, this article shows both feasibility and limits of an automatic approach for the generation of safe operation sequences based on reachability analysis.

This article deals with the validation of critical industrial process architectures from the point of view of safety and operation. During the engineering phases, the objective is to complement conventional safety studies with an approach that focuses on plant operation. In this context, one of the major challenges is to provide a guarantee that the designed architecture will be able to react safely to critical situations and events. To face the complexity resulting from the large number of functionalities and devices of the installations under consideration, the proposed approach is based on dynamic models of architectures, using the formalism of timed automata and reachability analysis to verify that, given a particular configuration of an architecture, the process can be safely operated to achieve a given objective. The result is a formal tool that allows engineers and plant operators to evaluate architecture safety with different types of dysfunctional scenarios based on their operational safety expertise. The article presents the formal modelling framework, which emphasizes structured modelling using patterns to promote reuse and instantiation over several candidate architectures. The contribution is illustrated and discussed using an experimental laboratory platform.

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The main objective of operation procedure engineering for complex and critical systems is to provide action sequences satisfying safety requirements specifications. A classical limit of the use of formal generation approaches for this purpose is the combinatorial explosion due to the size and the number of required models. This article addresses this issue by proposing an iterative approach for the generation of safe operation sequences, using timed automata, and based on reachability analysis. The originality of this approach is to combine a bottom-up framework to build progressively system models by abstraction, and a top-down iterative action sequence generation.