Design of a Control System for a Reconfigurable Engine Assembly Line

Today’s automotive manufacturing environment is dynamic. It is characterized by short life cycles of products especially in powertrain, due in part to changing Government regulations for fuel economy. In the USA, the National Highway Traffic and Safety Administration (NHTSA), Corporate Average Fuel Economy (CAFE) mandates an average of 29 miles per gallon (mpg), gradually increasing to 35.5 mpg by 2016 and 54.5 mpg towards 2025. Life cycles of engines and transmissions have consequently shortened, driving automakers to develop and manufacture more efficient powertrains. Not long ago, plants produced engines for decades, with minor modifications warranting slight manufacturing line rework. Conversely, today’s changing trends require machines and complete engine line overhauls rendering initial setups obsolete. Automakers compete to satisfy government regulations for best mileage and also lower manufacturing cost, thus the adoption of Reconfigurable Manufacturing Systems (RMS). Production lines follow modularity in designs, for hardware and software, to adapt to new business conditions, economically and time-wise. Information Technology (IT) and Controls are growing closer with the line of demarcation disappearing in manufacturing. Controls are benefiting from opportunities in IT, hardware and software. The advent of agent-based technology which are autonomous, cooperative and extendible in different production activities, helped to develop controls for RMS in academia. Component-based software suitable for RMS modularity and plug-and-play hardware/software components has gained decades of popularity in the software industry. This thesis implements distributed controls imbedding component-based technology and IEC 61311-3 function block standard for automotive engine assembly, which will contribute to these developments. The control architecture provides reconfigurability which is lacking in current manufacturing systems. The research imbeds: 1- Reconfigurability - Fitting RMS-designed hardware towards new manufacturing, 2- Reusability - Building software library for reuse across assembly lines, and 3- Plug-and-Play - Embedding easy to assemble software components (function blocks)

Describing Structure and Complex Interactions in Multi-Agent-Based Industrial Cyber-Physical Systems

The description of structure and complex interactions in Multi-agent-based Industrial Cyber-physical (MAS-ICPS) systems has been elusively addressed in the literature. Existing works, grounded on model-based engineering, have been successful at characterizing and solving system integration problems. However, they fail to describe accurately the collective and dynamic execution behaviour of large and complex industrial systems, particularly in more discrete production domains, such as: automotive, home appliances, aerospace, food and beverages, etc. In these domains, the execution flow diverts dynamically due to production disturbances, custom orders, fluctuations in demand in mixed model production, faults, quality-control and product rework, etc. These dynamic conditions require re-allocation and reconfiguration of production resources, redirection of production flows, re-scheduling of orders, etc. A meta-model for describing the structure and complex interactions in MAS-ICPS is defined in this paper. This contribution goes beyond the State-Of-The-Art (SOTA) as the proposed meta-model describes structure, as many other literature contributions, but also describes the execution behaviour of arbitrarily complex interactions. The previous is achieved with the introduction of general execution flow control operators in the meta-model. These operators cover, among other aspects, delegation of the execution flow and dynamic decision making. Additionally, the contribution also goes beyond the SOTA by including validation mechanisms for the models generated by the meta-model. Finally, the contribution adds to the current literature by providing a meta-model focusing on production execution and not just on describing the structural connectivity aspects of ICPSs.publishersversionpublishe

A comparison of the manufacturing resilience between fixed automation systems and mobile robots in large structure assembly

The modern manufacturing industry is undergoing major transformations due to global competition and rapidly changing market demands. Traditional systems with rigid structures are very difficult to reconfigure every time a change in production is required. A promising alternative to these is seen in mobile, self-organising manufacturing systems, where self-deploying and independent entities such as mobile robots are used to facilitate a more reconfigurable assembly process. In addition, an integral part of manufacturing is the transportation of components within the manufacturing environment. Conveyor systems are often unsuitable for moving components that are large, heavy or awkward, making them difficult to use in large structure assembly. Currently, such components are commonly transported by cranes to dedicated automation systems which are seen as expensive and unadaptable. In this paper we investigate the differences in resilience to variations between a set of mobile robots and the widely accepted fixed automation systems under different conditions. Therefore, instead of transporting components or parts to manufacturing equipment we analyse the potential benefits of transporting the equipment to the large parts. By means of simulations, the two systems are compared to one-another in scenarios of identical part arrival times and part processing capacities. Assuming equal production rates, we assess their ability to respond to (1) rush orders, (2) variable arrival times and (3) production mix variation. Currently, there are no specific algorithms for process control of such mobile systems. For this reason we apply the First-In-First-Out task-selection rule. We present a comparison of resilience measures between the systems

Architecting a System Model for Personalized Healthcare Delivery and Managed Individual Health Outcomes

In recent years, healthcare needs have shifted from treating acute conditions to meeting an unprecedented chronic disease burden. The healthcare delivery system has structurally evolved to address two primary features of acute care: the relatively short time period, on the order of a patient encounter, and the siloed focus on organs or organ systems, thereby operationally fragmenting and providing care by organ specialty. Much more so than acute conditions, chronic disease involves multiple health factors with complex interactions between them over a prolonged period of time necessitating a healthcare delivery model that is personalized to achieve individual health outcomes. Using the current acute-based healthcare delivery system to address and provide care to patients with chronic disease has led to significant complexity in the healthcare delivery system. This presents a formidable systems’ challenge where the state of the healthcare delivery system must be coordinated over many years or decades with the health state of each individual that seeks care for their chronic conditions. This paper architects a system model for personalized healthcare delivery and managed individual health outcomes. To ground the discussion, the work builds upon recent structural analysis of mass-customized production systems as an analogous system and then highlights the stochastic evolution of an individual’s health state as a key distinguishing feature

Increase the adoption of Agent-based Cyber-Physical Production Systems through the Design of Minimally Invasive Solutions

During the last few years, many approaches were proposed to offer companies the ability to have dynamic and flexible production systems. One of the conventional ap-proaches to solving this problem is the implementation of cyber-physical production sys-tems using multi-agent distributed systems. Although these systems can deal with several challenges faced by companies in this area, they have not been accepted and used in real cases. In this way, the primary objective of the proposed work is to understand the chal-lenges usually found in the adoption of these solutions and to develop a strategy to in-crease their acceptance and implementation. Thus, the document focuses on the design and development of cyber-physical produc-tion systems based on agent approaches, requiring minimal changes in the existing pro-duction systems. This approach aims of reducing the impact and the alterations needed to adopt those new cyber-physical production systems. Clarifying the subject, the author presents a definition of a minimal invasive agent-based cyber-physical production system and, the functional requirements that the designers and developers must respect to imple-ment the new software. From these functional requirements derived a list of design princi-ples that must be fulfilled to design and develop a system with these characteristics. Subsequently, to evaluate solutions that aim to be minimally invasive, an evaluation model based on a fuzzy inference system is proposed, which rank the approaches accord-ing to each of the design principles and globally. In this way, the proposed work presents the functional requirements, design principles and evaluation model of minimally invasive cyber-physical production systems, to increase the adoption of such systems

Applications of Axiomatic Design in academic publications 2013-2018 : A Systematic Literature Review

Aksiomaattinen suunnitteluteoria on ollut kasvavan kiinnostuksen kohteena tiedeyhteisössä siitä lähtien, kun Nam P. Suh esitteli teorian 1990-luvulla. Siitä huolimatta, että aiheesta on tehty runsaasti aktiivista tutkimusta (muun muassa vuotuinen aksiomaattiseen suunnitteluteoriaan keskittynyt konferenssi), kattavia kirjallisuuskatsauksia on kirjoitettu vähän. Tämä tutkimus pyrkii osaltaan täyttämään edelläkuvattua aukkoa aksiomaattisen suunnitteluteorian tutkimuskentällä, keskittyen julkaisuihin vuodesta 2013 vuoteen 2018. Tutkimus on kirjoitettu jatkumoksi vuonna 2010 tutkijoiden Kulak, Cebi & Kahmaran (2010) julkaisemalle kirjallisuuskatsakuselle. Tämän vuoksi samankaltainen kategorisointi on implementoitu tähän tutkimukseen. Kategorisoinnin perusteina ovat käytetty aksiooma, sovellutusalue, metodologia ja määrittelytyyppi. Sovellutusalueisiin on tässä tutkimuksessa lisätty ’palvelut’ omana, uutena kategorianaan. Työssä esitellään lyhyesti aksiomaattinen suunnitteluteoria ja sen keskeiset osa- alueet, tärkeimpinä sunnnittelualueet, suunnitteluprosessi ja suunnitteluaksioomat. Metodologia-osiossa taustoitetaan systemaattisen kirjallisuuskatsauksen soveltamista tähän tutkimukseen ja kuvataan prosessin toteutus PRISMA-mallia käyttäen. Tutkimustulokset käydään lyhyesti läpi esimerkein kustakin kategoriasta. Tutkimusaineisto esitetään sekä lukuina, liitteenä että graaffeina. Näitä kirjallisuuskatsauksen tutkimustuloksia verrataan varhemman tutkimuksen vastaaviin. Sovelletun aksiooman suhteen merkittäviä muutoksia ei ole havaittavissa tämän tutkimuksen perusteella aikaisempaan kirjallisuuskatsaukseen verrattuna. Sovellutusaluessa, sitä vastoin, systeemisuunnittelun osuus on kasvanut merkittävästi edelliseen tutkimukseen verrattuna, kun taas ohjelmistosuunnittelun osuus on vastaavasti pienentynyt. Palvelusuunnittelun osuus on verrattain vaatimaton, joskin suurempi kuin esimerkiksi ohjelmistosuunnittelun. Tämän tutkimuksen perusteella suositellaan jatkotutkimuksia erityisesti aksiomaattisen suunitteluteorian sovellutuksista ohjelmisto- ja palvelusuunnitteluihin sekä mahdollisista syistä, miksi mainittujen sovellutusaljen osuus tutkimuskentässä on pienehkö.Axiomatic Design theory has been gaining growing interest within a design community since introduced by Nam P. Suh in 1990s. Despite an active research within the field, including yearly international conferences of Axiomatic Design, there is not many literature reviews made of academic publications of Axiomatic Design. This research aims to fulfil previously described gap on secondary research of Axiomatic Design, focusing on papers published between 2013 and 2018. The study is a continuum to previous paper published by Kulak, Cebi & Kahmaran (2010). Therefore, similar categorization based on applied axiom, application area, methodology and evaluation type is applied in this research. In application area, ‘services’ have been added as a new category for this research. Results are compared with previous study. In findings, no siginificant change has happened in applied axiom, Independece axiom still being clearly more popular within academic publications. In application area, however, there are noticeable changes compared to the previous study. Share of system design has increased while softare design has significantly decreased. Future research is recommended to further explore specifically applications of Axiomatic Design in software and in services

A Tensor-Based Formulation of Hetero-functional Graph Theory

Recently, hetero-functional graph theory (HFGT) has developed as a means to mathematically model the structure of large flexible engineering systems. In that regard, it intellectually resembles a fusion of network science and model-based systems engineering. With respect to the former, it relies on multiple graphs as data structures so as to support matrix-based quantitative analysis. In the meantime, HFGT explicitly embodies the heterogeneity of conceptual and ontological constructs found in model-based systems engineering including system form, system function, and system concept. At their foundation, these disparate conceptual constructs suggest multi-dimensional rather than two-dimensional relationships. This paper provides the first tensor-based treatment of some of the most important parts of hetero-functional graph theory. In particular, it addresses the "system concept", the hetero-functional adjacency matrix, and the hetero-functional incidence tensor. The tensor-based formulation described in this work makes a stronger tie between HFGT and its ontological foundations in MBSE. Finally, the tensor-based formulation facilitates an understanding of the relationships between HFGT and multi-layer networks