A Systematic Modelling Procedure to Design Agent-Oriented Control to Coalition of Capabilities - In the Context of I4.0 as Virtual Assets (AAS)

: Manufacturing systems need to meet I4.0 guidelines to deal with uncertainty in scenarios 1 of turbulent demand for products. The engineering concepts to define the service’s resources 2 to manufacture the products will be more flexible, ensuring the possibility of re-planning in 3 operation. These can follow the engineering paradigm based on capabilities. The virtualization of 4 industry components and assets achieves the RAMI 4.0 guidelines and (I4.0C), which describes 5 the Asset Administration Shell (AAS). However, AAS are passive components that provide 6 information about I4.0 assets. The proposal of specific paradigms is exposed for managing 7 these components, as is the case of multi-agent systems (MAS) that attribute intelligence to 8 objects. The implementation of resource coalitions with evolutionary architectures (EAS) applies 9 cooperation and capabilities’ association. Therefore, this work focuses on designing a method for 10 modeling the asset administration shell (AAS) as virtual elements orchestrating intelligent agents 11 (MAS) that attribute cooperation and negotiation through contracts to coalitions based on the 12 engineering capabilities concept. The systematic method suggested in this work is partitioned for 13 the composition of objects, AAS elements, and activities that guarantee the relationship between 14 entities. Finally, Production Flow Schema (PFS) refinements are applied to generate the final Petri 15 net models (PN) and validate them with Snoopy simulations. The results achieved demonstrate the 16 validation of the procedure, eliminating interlocking and enabling liveliness to integrate elements 17 behavior. 18


Introduction
Industry 4.0 (I4.0) drives global strategies in manufacturing systems to deal with 23 turbulent product demands [1]. Traditional industry engineering tasks systematize each 24 application: i) the development tools specify the project functionalities; ii) establish the 25 necessary resources and, iii) formalize the process -determining the capabilities of the 26 real assets (Skills). However, unpredictable behaviors can occur when the production 27 phase starts, such as unavailability of resources or a new product insertion, causing a 28 re-planning in production. [2,3]. 29 In the current production paradigms, a rigid connection exists between the real 30 asset functionality and digital services offered, but this approach does not meet the 31 concepts of I4.0. [3,4].The [1] treats the need to modernize the processes involved in 32 manufacturing with the use of appropriate ontologies that enable digital models. A 33 digital representation of resources was presented in [5] which establishes guidelines (EAS) [9,10]. This concept is related to the control of intelligent entities that impose 50 self-organization, cooperation, and reasoning to fill the need to add intelligence to I4.0C 51 [8]. These components are active objects that internally have knowledge and capacity to 52 learn with the environment, seek new capabilities and, negotiate with the agent society 53 [11]. 54 The aspects described related to distributed intelligent systems (DAI), a specific 55 area of Artificial Intelligence (AI) [12]. Intelligent agents are fundamental components 56 for control, optimizing, improve and organizing the manufacturing process. The agents 57 are helpful to model interactions between intelligent entities, which are responsible for 58 attributing to the system characteristics such as cooperation, coexistence, or competition 59 [13]. The use cases studied apply emerging methods to add intelligence in AAS; integrate 60 the real and virtual component [14]; data management elements [15]; or enable the 61 control of entities for reconfiguration [16]. This works proposal presents a process for 62 modeling intelligent assets following the context of I4.0. The AAS describes capabilities 63 and allows to share resources skills (Skill) as a society of agents that seek coalition 64 through contracts to meet a specific production plan.

Contextualizing Industry 4.0 89
The Fourth Industrial Revolution gained strength mainly with the German initia-90 tives to modernize manufacturing systems, seeking to introduce traditional approaches 91 to the context of Industry 4.0 (I4.0) [17]. The globalization demands proposals for in-92 tegrating the entire manufacturing value chain, communication between machines, 93 hierarchical levels, and applications involved in the production process, distributed 94 production, and sharing of resources. The massive use of information and technolo-95 gies is present in virtual manufacturing environments; however, significant efforts are 96 committed to standardizing legacy applications to I4.0 [1]. 97 The Manufacturing environments describe activities through discrete processes that 98 cooperate with elements and applications to achieve a particular goal. In the traditional 99 manufacturing systems: 100 • this cooperation provides a static and pre-defined model; however, the I4.0 char-101 acterized by uncertainty scenarios needs to change the engineering paradigms, 102 allowing located and self-organize assets [ Shell (AAS), and the Asset [6,7]. The Asset Administration Shell is the digital and active components and the connected, digital, and distributed world [2,6].

157
The AAS, presented in [2], has the purpose of assisting this information through 158 the design of sub-models specific for data standardization. Machines can interpret that 159 providing a context to represent the features, and AAS allows different applications in 160 particular domains. Since a consistent way of structuring information within the AAS is 161 necessary, consult the guidelines to establish a metamodel to meet this need [6].

162
An AAS consists of a header and a body, as depicted in Figure 1. The header 163 contains all information relevant to asset identification and AAS and, the body has all 164 properties and operations that describe the asset. These descriptions are into sub-models 165 that cover specific aspects of the active (e.g., functionalities, skills, and abilities) [2].

166
The conception of an AAS metamodel as a UML class diagram describes all the 167 leading entities adopting the information structure. This work proposal has used these 168 technicians to describe virtual assets using AAS. In this case, was chosen the following used to define the relationship between two or more elements; d) AssetInformation, the 174 identification of asset metadata is defined as represented by AAS.

175
These works propose the design of metamodels, PAS, and RAS as AAS designed 176 with UML diagram presented in [2]. The extraction of minimum sub-models follows the 177 I4.0 guidelines. for modeling software. The PFS understands a high-level language independent of 184 technologies and manufacturers widely used to design system processes [19,20].

193
The PN execution characterizes marks flowing in the process, which changes ac-194 cording to the transitions triggering. A transition triggers the previous marks, allowing 195 the flow towards the arcs that connect the post-transition places. [19,20].

196
The PN models generated in this work proposal were validated using an engi-

219
The classes diagram was chosen in this works, being functional models for repre-220 senting the individual components of the MAS control system [22].  The work of [19] presented an architectural proposal to discover and select equip- However, this work is more focused on specifying service components for RAMI4.0 283 layers. It is currently considered a large number of legacy devices that need to adhere to 284 the context of I4.0. Initially, these devices migrate to web services from cloud platforms.

285
In this sense, the work of [23] describes an approach to integrating legacy devices to a Engineering. In the field of mechatronic engineering, the [18] presents a procedure to systematize the specification of virtual components and their functionalities in the 304 production system, following the I4.0 guidelines.

305
In this context, the work of [14] presents a proposal to develop new control solutions 306 based on I4.0 for legacy manufacturing systems. The work proposes the communica-307 tion and integration of legacy manufacturing systems using AAS, IoT, and distributed 308 architectures.

309
The proposal of this work is considered an extension of [7]  The reconfiguration and plug-and-produce follow the descriptions of the I4.0 [2,5].

320
The DT presented in [3] as the key to shifting the paradigms in manufacturing concepts.

321
However, it is necessary to describe the relationship between assets, allowing them 322 to search for data, using different protocols and languages that represent the I4.0Cs and communication [6].

328
The [5] discusses the relationship between AAS, seeking to demonstrate different 329 granularity levels of the resources' attributes and aggregation of assets functionalities.

330
The sum of capabilities seen in various AAS can result in a new AAS, thus creating a new 331 I4.0C. These works [2,5] are in early stages, but the details presented on these concepts 332 can be used for proposals that specify a methodology that allows the design of models 333 to orchestrate the different relationships between AAS, such as a coalition of resource 334 capabilities. In this sense, the work [8] performs architectural specifications that make it 335 possible to implement the concepts of self-organization, plug-and-produce in the context 336 of I4.0. The complex evolutionary systems seem to be the state-of-the-art guidelines to 337 grant cooperation and grouping of resource abilities.

338
The works [2,5,6] contribute to the proposal of this work with ontological descrip-

348
This work describes a systematic modeling method to design agent-oriented control 349 seeking to organize Skills related to AAS. This method will apply to virtual entities, 350 coalitions, and the self-organization of assets.  proposed procedure using simplification until achieving the PN.

368
The Table 2  Mechanism" Table 2.  The agent society can go to the next step that concerns the request for "Contracts

435
This section presents the method used to validate the supported procedure by PN 436 diagrams. In this sense, the individual activity models demonstrate the "Capabilities 437 Coalition (MCC)" process. The collaboration process starts with interactions between the components repre-515 sented by transitions as follows ( Figure 12 programmer activities. Therefore, the process described eliminates the Interlocks and 557 guarantees the stability of the process sequence according to the reasoning provided in 558 the previous steps ( Figure 13).

559
The chosen systematic implements modeling techniques in a split proposal in stages 560 prove to be efficient for the early stages of developing MAS-based control software or 561 application. This procedure contributes to the specification of component activities 562 and reduces efforts to implement the models. The MAS designers use OO techniques; 563 however, the system's complexity is unavoidable.

564
It is understood that this proposal is an academic scenario of low complexity; 565 however, in real use cases, the number of AAS submodels can increase significantly.

566
So the methods assigned with PFS in a top-down approach helps modelers reduce 567 the complexity of systems by generating simplified models in PN for validation of 568 components and relationship between AAS objects and agents.