Smart factories are complex environments equipped with both production machinery and computing devices that collect, share, and analyze data. For this reason, the modeling of today's factories can no longer rely on traditional methods, and computer engineering tools, such as SysML, must be employed. At the same time, the current SysML v1. * standard does not provide the rigorousness required to model the complexity and the criticalities of a smart factory. Recently, SysML v2 has been proposed and is about to be released as the new version of the standard. Its release candidate version shows the new version aims at providing a more rigorous and complete modeling language, able to fulfill the requirements of the smart factory domain. In this paper, we explore the capabilities of the new SysML v2 standard by building a rigorous modeling strategy, able to capture the aspects of a smart factory related to the production process, the computation and the communication. We apply the proposed strategy to model a fully-fledged smart factory, and we rely on models to automatically configure the different pieces of equipment and software components in the factory.

The DeFacto project, supported by the European Commission via a Marie Skłodowska-Curie Global Individual Fellowship, tackles the complexity arising from the transformation of industrial manufacturing systems into intricate cyber-physical systems. This evolution offers unprecedented opportunities but also poses intellectual and engineering challenges. DeFacto aims to advance the design automation of cyber-physical production systems by developing innovative modeling paradigms, scalable algorithms, software architectures, and tools. In the DeFacto approach, production systems are managed through service-oriented manufacturing software architectures. System-level models capture the features and the requirements of production systems, representing both production and computational processes as services provided by the infrastructure. Methodologies for system analysis and optimization rely on compositional abstractions of system behaviors grounded in assume-guarantee contracts. This paper outlines key research endeavors, findings, and lessons learned from the DeFacto project.

This article introduces the regionalized resource process dependence graphs (RRPDGs): a manufacturing processes representation inspired by the regionalized value state dependence graphs traditionally used in software compilers. An RRPDG is an ordered sequence of nodes, each characterized by stereotyped input and output parameters, encapsulating a transformation of the process state (e.g., a manufacturing operation). RRPDG allow defining complex transformations by composing a set of nodes (i.e., regions), hiding the internal details. Then, RRPDGs are used to automatically reasoning over dynamic reconfiguration and process optimization: an instance of the A-star search algorithm is used to search for possible transformations while pursuing an optimization function. The rules defined in this article over RRPDG models enforce the transformations' correctness. We use RRPDGs to model a real production system while the transformation rules are applied to optimize the system's processes. The proposed representation reduced the search complexity in each experiment, allowing to reach an optimal solution also in the case for which classical approaches were unable to complete before reaching the timeout. In all the experiments, the cost of the solution produced by using the regionalized representation is minor than the the solution produced by using the classical representation.

In this paper, we present the project “VIR2EM: VIrtualization and Remotization for Resilient and Efficient Manufacturing” by providing details on its research themes and its scientific and technological output. The project, centered on virtualization and remotization in the industrial sector, was promoted by Regione Veneto in Italy, and it has seen the participation and collaboration of 3 universities, 1 public research entity, and 10 companies composed of end users of digital solutions and high knowledge-intensive service providers. The project aims to develop and use tools for the virtualization of processes, systems, resources, and remoting of operations in order to: (1) maximize the efficiency of manufacturing systems under normal operating conditions; (2) maintain operations in case of emergency situations; (3) facilitate the restart of operations downstream of emergency situations by ensuring flexibility and predictive capability. Each theoretical proposal has been validated in distinct industrial facilities by constructing ten different prototypes.

This paper presents a software architecture extending the classical automation pyramid to control and reconfigure flexible, service-oriented manufacturing systems. At the Planning level, the architecture requires a Manufacturing Execution System (MES) consistent with the International Society of Automation (ISA) standard. Then, the Supervisory level is automated by introducing a novel component, called Automation Manager. The new component interacts upward with the MES, and downward with a set of servers providing access to the manufacturing machines. The communication with machines relies on the OPC Unified Architecture (OPC UA) standard protocol, which allows exposing production tasks as “services”. The proposed software architecture has been prototyped to control a real production line, originally controlled by a commercial MES, unable to fully exploit the flexibility provided by the case study manufacturing system. Meanwhile, the proposed architecture is fully exploiting the production line's flexibility.

Manufacturing systems require a careful scheduling of the resource usage to maximize the production efficiency. In a completely automated environment, the transport system should be orchestrated to work smoothly with the other resources. While the impact of job characteristics, such as fixed or variable processing times of the tasks composing the jobs, or task dependencies, has been extensively studied, the role of the transport system has received less attention.In this paper we consider a conveyor belt as a mean of transportation among a set of production machines. In this scenario, there is no input or output buffer at the machines, and the transport times depend on the availability of the machines. We propose a heuristic based on randomization, called SCHED-T, which is able to find a near optimal joint schedule for job processing and transfer in few seconds. We test our solution on known benchmarks, along with real-world instances, showing that our scheduler is able to predict accurately the overall processing time of a production line.

Products and materials traceability is essential in modern manufacturing, where the production must meet certain standards that range from Quality Control (QC) to the quality of the used materials. In this environment, blockchain applications allow certifying data provenience and subsequent modification, offering trust and security along the entire supply chain. Nonetheless, the design and the development of such applications are usually performed manually and, thus, subject to errors.In this paper, we propose a methodology allowing to automatically generate smart contracts starting from a SysML model. This approach allows easing the integration of blockchain applications in a production system: by abstracting the implementations with models, it is possible to generate smart contracts for different blockchains, connecting to multiple production environments.We applied the proposed methodology on a real manufacturing system, assessing the quality of a case-study production.

Manufacturing lines are evolving into complex cyber-physical production systems. However, their growth in complexity is not matched by the development of structured modeling and design methodologies. In particular, approaches exploiting both models typical of the manufacturing domain and models used by computer engineers are still missing. In this work, we outline a design flow contemplating the reuse of already existing manufacturing lines' models, while designing novel advanced production systems. To enable such a flow, we propose a methodology extracting System Modeling Language (SysML) structural diagrams from AutomationML descriptions. Then, we propose to design the system functionalities on top of the produced diagrams. The paper shows the application of the methodology to a concrete manufacturing line, the structure of which was originally modeled using AutomationML. To exemplify the advantages of the methodology, we exploit the models being generated to automatically extract a digital twin for the production system transportation line. The resulting digital twin is compliant with a well-known plant simulation tool.

The Industry 4.0 trend speeds up the adoption of a variety of technologies. In modern manufacturing, system data are collected both from the field through sensors and by exploiting complex simulations. Data analysis techniques became crucial to build and maintain any efficient production line, while autonomous systems and robots are the main focus of researchers and practitioners. This pervasive use of artificial intelligence derived technologies pushed humans to the border of production systems. Industry 5.0 aims at bringing the attention back to humans in production lines while magnifying their interactions with intelligent systems. This new trend will impact the design of future manufacturing infrastructures, increasing their complexity. Engineers will need modeling and developing tools able to capture this complexity. In this paper, we analyze the modeling languages and tools being used, identifying their strengths and weaknesses. Then, we propose some possible directions to provide engineers with the expressive power needed to tackle the challenges posed by Industry 5.0.

This article presents a methodology to formalize the behavior of the machines composing a production line, and to automatically generate their virtual prototypes for efficient and correct plant simulation. The approach exploits assume-guarantee reasoning through contracts to model the interaction between the different components of a production line. The approach is guided by a well-known taxonomy of industrial machines and associated manufacturing processes to identify each elementary action related to a specific machine. Contracts enable to build executable models of all the machines available in the production line by using automatic synthesis. The generated models can be integrated into a state-of-the-practice industrial plant simulation software to estimate and validate the production line's behavior. The presentation of the methodology is supported by a running example based on a real production line, showing the step-by-step application of the approach to a concrete scenario.

The advent of Industry 4.0 is making production processes every day more complicated. As such, early process validation is becoming crucial to avoid production errors thus decreasing costs. In this paper, we present an approach to validate production recipes. Initially, the recipe is specified according to the ISA-95 standard, while the production plant is described using AutomationML. These specifications are formalized into a hierarchy of assume-guarantee contracts. Each contract specifies a set of temporal behaviors, characterizing the different machines composing the production line, their actions and interaction. Then, the formal specifications provided by the contracts are systematically synthesized to automatically generate a digital twin for the production line. Finally, the digital twin is used to evaluate, and validate, both the functional and the extra-functional characteristics of the system.The methodology has been applied to validate the production of a product requiring additive manufacturing, robotic assembling and transportation.

This paper analyzes a set of languages and standard used when designing industrial plants. It focuses on AutomationML and B2MML to specify respectively the architecture and the intended production of the system being designed. It also relies on the DIN 8580 standard to describe the actions performed by each machine composing the production line. Then, it outlines a methodology starting by mapping the information expressed by the analyzed languages and standards into the Assume-Guarantee Contracts formalism. It exploits contract-based design concepts to tackle the increase automation of the industrial plant design process and to enable the generation of digital twins. The approach is outlined by showing its applicability to a concrete manufacturing scenario.

The approach we present in this paper exploits assume-guarantee reasoning through contracts to model a production line, and to generate its virtual prototype for efficient and correct plant simulation. Contracts are used to model the different parts composing the line; the modeling is guided by a well-known taxonomy associating industrial machines to manufacturing processes and their elementary actions, each represented by a contract. The composition of contracts representing the actions of a machine specifies each possible manufacturing process implemented by the machine. Then, automatic synthesis from contracts is used to generate an executable model of the machines composing the plant. The generated models are finally integrated into a state-of-the-practice industrial plant simulation software to validate the execution of the production line.The entire methodology is presented by showing its step-by-step application to a concrete scenario.

This paper presents a methodology that relies on Assume-Guarantee Contracts to decompose the problem of synthesizing control software for a multi-robot system. Initially, each contract describes either a component ( e.g. , a robot) or an aspect of the system. Then, the design problem is decomposed into different synthesis and verification sub-problems, allowing to tackle the complexity involved in the design process. The design problem is then recomposed by exploiting the rigorousness provided by contracts. This allows us to achieve system-level simulation capable to be used for validating the entire design. Once validated, the software synthesized during the process can be integrated into Robot Operating System (ROS) nodes and executed using state-of-the-practice packages and tools for modern robotic systems. We apply the methodology to generate a control strategy for an autonomous goods transportation system. Our results show a massive reduction of the time required to obtain automatically the control software implementing a multi-robot mission.