How environment dynamics affects production scheduling: requirements for development of CPPS models

Production scheduling can be affected by many disturbances in the manufacturing system, and consequently, the feasible schedules previously defined became obsolete. Emerging of new technologies associated with Industry 4.0, such as Cyber-Physical Production Systems, as a paradigm of implementation of control and support in decision making, should embed the capacity to simulate different environment scenarios based on the data collected by the manufacturing systems. This paper presents the evaluation of environment dynamics effect on production scheduling, considering three scheduling models and three environment scenarios, through a case study. Results show that environment dynamics affect production schedules, and a very strong or strong positive correlation between environment dynamics scenarios and total completion time with delay, over three scheduling paradigms. Based on these results, the requirement for mandatory inclusion of a module for different environment dynamics scenarios generation and the corresponded simulations, of a Cyber-Physical Production Systems architecture, is confirmed.This work has been supported by FCT -Fundacao para a Ciencia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

Decision Support Systems in the Context of Cyber-Physical Systems: Influencing Factors and Challenges for the Adoption in Production Scheduling

Cyber-physical systems promise a complete networking of all actors and resources involved in production and thus an improved availability of information. In this context decision support systems enable appropriate processing and presentation of the captured data. In particular, production scheduling could benefit from this, since it is responsible for the short-term planning and control of released orders. Since decision support systems and cyber-physical systems together are not yet widely used in production scheduling, the aim of this research study is to analyze the adoption of these technologies. In order to do so, we conducted a qualitative interview study with experts on production scheduling. Thereby, we identified eleven influencing factors and 22 related challenges, which affect the adoption of decision support systems in production scheduling in the context of cyber-physical systems. The results help to explain the adoption and can serve as a starting point for the development of those systems

Sistemas Ciberfísicos orientados para a Produção Aberta

O objetivo principal deste trabalho passa por estabelecer um sistema ciberfísico orientado para a comunidade no âmbito da produção aberta, recorrendo, então, ao Open Design. Nesse contexto, numa primeira fase, é feita uma revisão bibliográfica sobre estes conceitos, da qual não foram identificados quaisquer trabalhos já realizados que abrangessem tal finalidade. Mesmo assim, e com base no material obtido dessa revisão, juntamente com documentação relativa a trabalhos enquadrados no tema, define-se uma arquitetura, por camadas, que satisfaz o pretendido e enquadra-se na premissa open-source e/ou low-cost. Efetivamente, é elaborado um sistema que permite a qualquer utilizador o acesso livre a um repositório onde se encontra disponível uma vasta gama de produtos, personalizados ou não, os quais são facultados pela própria comunidade. Para que o processamento da informação congruente seja realizável sem limitações, a maior parte do mesmo está alocada na cloud, o qual será auxiliado por um Sistema de MultiAgentes. De seguida, estabelece-se uma ponte de ligação com o mundo físico, por meio de interfaces CPS viabilizadas por dispositivos IoT, os quais conectam e controlam recursos físicos simbólicos à Manufatura Aditiva e Subtrativa, com a finalidade de produzir o produto pretendido. Nesta fase, é possibilitado ao operador e à comunidade acompanhar em tempo real todas as ações e operações realizadas pelos recursos físicos referidos. Juntamente com estes últimos intervenientes, existem igualmente máquinas e processos a cooperar e colaborar simbioticamente para o refinamento do processo de produção, através da análise e recálculo dos dados relacionados com o mesmo. De forma a concretizar esta arquitetura, a implementação da mesma é iniciada, primeiramente a nível físico e, posteriormente, a nível computacional/digital.The main objective of this work is to establish a cyberphysical system oriented to the community within the scope of open production, resorting, then, to Open Design. In this context, in a first phase, a bibliographic review of these concepts is carried out, from which no work that had already been carried out covering this purpose was identified. Even so, and based on the material obtained from this review, together with documentation related to works framed in the theme, an architecture is defined, in layers, which satisfies the intended purpose and falls under the open-source and/or low-cost premise. In fact, a system is created that allows any user free access to a repository where a wide range of products, personalized or not, are available, which are provided by the community itself. For the processing of congruent information to be feasible without limitations, most of it is allocated in the cloud, a process better known as Cloud Computing, which will be supported by a Multi-Agent System. Then, a connection bridge with the physical world is established, through CPS interfaces made possible by IoT devices, which connect and control symbolic physical resources to the Additive and Subtractive Manufacturing, to produce the intended product. At this stage, it is possible for the operator and the community to monitor in real time all actions and operations carried out by the aforementioned resources. Along with these last participants, there are also machines and processes to cooperate and collaborate symbiotically for the refinement of the production process, through the analysis and recalculation of the data related to it. To realize this architecture, its implementation is started, firstly at the physical level and, later, at the computational/digital level