Table 2 (Abstract P9). Agent communication in the digital twin framework for industrial production processes

Related agents

Their primary communication

Product and process agents

Generally, the framework recognizes that a product should pass through a number of production processes to be completed. Once the product has completed a process, it is transferred. The products will transfer to the next production step through a conveyor or other means of transportation between the processes.

Product and conveyor/ transportation agents

To transfer the products within the production, the products will be moved by either conveyor or transport. The conveyor may hold multiple product agents at the same time. Unless otherwise specified, the movement will adhere to FIFO.

Product and batch agents

All product agents within the production are assigned a batch. The batch holds logistical information that governs the start date, deadline, etc. The batch can, in some sense, be considered a parent class from which the products inherit logistical information. The relationship is a one-to-many in which a batch can hold multiple product agents, but a product agent can only respond to one batch agent.

Process and environment agents

Within the framework, the product, process, transportation, and conveyor agents are all associated with a local environment. The relationship follows a one-to-many principle in which an environment can hold multiple of the previously mentioned agents. However, each of the agents can only respond to one environment. The features of the environment may vary based on the case, but examples of environment features include temperature, light levels, carbon dioxide concentrations etc. Furthermore, the environment agent holds the possibility for external data integration through, e.g., IoT sensors, which allow real-time monitoring of the specific environment.

Resource and other agents

A resource is considered any entity required to act. Furthermore, the individual resource units can be assigned varying parameters related to specific task availability. This allows differentiating the resource population and having multiple resource populations within the DT. E.g., a specific task within a production facility may require personnel with specific knowledge, certification, etc., to perform. This can be captured through the different populations. Tasks will be assigned based on user input as the tasks required within specific facilities can vary greatly. The tasks can be created to use specific resource units and a specified number of resource units.

Planning and other agents

The planning agent is the central operational component from which several decisions are taken. The planning agent monitors the current state and number of products staying in the processes, conveyors, and transportation agents and chooses when and where to move the product agents. The planning agent refers to the batches associated with the products To determine if the products within the batch are on schedule or delayed. The planning agent is also the external communication point from which information within the DT is communicated to existing control systems, EPR, etc.