EUROPEAN CONFERENCE ON QUEUEING THEORY 2016

International audienceThis booklet contains the proceedings of the second European Conference in Queueing Theory (ECQT) that was held from the 18th to the 20th of July 2016 at the engineering school ENSEEIHT, Toulouse, France. ECQT is a biannual event where scientists and technicians in queueing theory and related areas get together to promote research, encourage interaction and exchange ideas. The spirit of the conference is to be a queueing event organized from within Europe, but open to participants from all over the world. The technical program of the 2016 edition consisted of 112 presentations organized in 29 sessions covering all trends in queueing theory, including the development of the theory, methodology advances, computational aspects and applications. Another exciting feature of ECQT2016 was the institution of the Takács Award for outstanding PhD thesis on "Queueing Theory and its Applications"

Development of a Hybrid Control and Monitoring System within a Reconfigurable Assembly System

Published ThesisExpanding global markets are constantly changing and unstable. South African manufacturing companies need to develop similar levels of sophistication and expertise in the automation industry as its international rivals, to compete for these markets and meet rising consumer expectations. To remain competitive, these manufacturing companies must manage their plants extremely efficiently to ensure the quality of assembled products; allow for rapid product introduction and product changes; achieve shortened throughput cycles; ensure more reliable delivery dates; and effectively coordinate product demand while contending with decreased product lifespans. To accomplish this, manufacturing companies in SA are progressively engaging in the current trend in automation known as reconfigurable manufacturing. Due to the extreme flexibility of these reconfigurable systems, the monitor and control systems for these require the same levels of flexibility. The purpose of the study is to develop a hybrid control and monitoring system, to supervise and control reconfigurable assembly systems (RAS), and adapt to the flexibility of these systems. To achieve this, a literature study was done in the research area to reveal the prerequisites for such systems; the physical assembly devices were designed and built; the separate software modules developed and ultimately integrated into the intended system. The tests to validate the system were developed in such a way that each subsection of the system is validated by using a different system software function. This inevitably confirms the functionality of the fundamental components and the system in entirety. The results indicated that devices are easily added to the system; devices are successfully detected and identified; how the system plans production, and how the system automatically configures itself. Further results showed the capability of the system to generate and virtually wire system runtime code; store and retrieve production data; as well as warn and alarm on unwanted conditions. By obtaining these results, companies can configure their systems with ease, in a shorter amount of time, and without any human error. Moreover, their systems will be more flexible, allow easy addition of new products and assembly devices, and with minimal downtime. This will enable SA manufacturing companies to be more competitive, ensure increased productivity, achieve extreme system flexibility, and decrease lead times – thus ensuring them an advantage over their international competitors

A machine entity for a coordinate measurement machine : the generic workcell project

The Center for Manufacturing Systems (CMS) department at New Jersey Institute of Technology and Siemens Corporate Research located in Princeton have agreed to jointly implement a research project in generic workcell control architectures. This paper discusses the module, called a Machine Entity, developed by the author that interfaces the Brown & Sharpe Coordinate Measurement Machine located on the CMS factory floor with the cell control software. The module has been designed in such a manner to simplify the development of future Machine Entities, thereby reducing the time required to integrate the CMS factory floor

Operator interfaces for the lifecycle support of component based automation systems

Current manufacturing automation systems (specifically the powertrain sector) have been facing challenges with constant pressures of globalisation, environmental concerns and ICT (Information and Communication Technology) innovations. These challenges instigate new demands for shorter product lifecycles and require customised products to be manufactured as efficiently as possible. Manufacturing systems must therefore be agile to remain competitive by supporting frequent reconfigurations involving distributed engineering activities. [Continues.

Simulation and Optimization of Production Control for Lean Manufacturing Transition

Lean manufacturing is an operations management philosophy that advocates eliminating waste, including work-in-process (WIP) inventory. A common mechanism for controlling WIP is "pull" production control, which limits the amount of WIP at each stage. The process of transforming a system from push production control to pull is not well understood or studied. This dissertation explores the events of a production control transition, quantifies its costs and develops techniques to minimize them. Simulation models of systems undergoing transition from push to pull are used to study this transient behavior. The transition of a single stage system is modeled. An objective function is introduced that defines transition cost in terms of the holding cost of orders in backlog and material in inventory. It incorporates two techniques for mitigating cost: temporarily deferring orders and adding extra capacity. It is shown that, except when backlog costs are high, it is better to transform the system quickly. It is also demonstrated that simulation based optimization is a viable tool to find the optimal transition strategy. Transition of a two-stage system is also modeled. The performance of two simple multi-stage transition strategies is measured. In the first, all of the stages are transformed at the same time. In the second, they are transformed one at a time. It is shown that the latter strategy is superior. Other strategies are also discussed. A new modeling formalism, the Production Control Framework (PCF), is introduced to facilitate automated searches for transition strategies in more complex systems. It is a hierarchical description of a manufacturing system built on a novel extension of the classic queue server model, which can express production control policy parametrically. The PCF is implemented in the form of a software template and its utility is shown as it is used to model and then find the optimal production control policy for a five stage system. This work provides the first practical guidance and insight into the behavior and cost of Lean production control transition, and it lays the groundwork for the development of optimal transition strategies for even the most complex manufacturing systems

A Framework for Industry 4.0

The potential of the Industry 4.0 will allow the national industry to develop all kinds of procedures, especially in terms of competitive differentiation. The prospects and motivations behind Industry 4.0 are related to the management that is essentially geared towards industrial internet, to the integrated analysis and use of data, to the digitalization of products and services, to new disruptive business models and to the cooperation within the value chain. It is through the integration of Cyber-Physical Systems (CPS), into the maintenance process that it is possible to carry out a continuous monitoring of industrial machines, as well as to apply advanced techniques for predictive and proactive maintenance. The present work is based on the MANTIS project, aiming to construct a specific platform for the proactive maintenance of industrial machines, targeting particularly the case of GreenBender ADIRA Steel Sheet. In other words, the aim is to reduce maintenance costs, increase the efficiency of the process and consequently the profit. Essentially, the MANTIS project is a multinational research project, where the CISTER Research Unit plays a key role, particularly in providing the communications infrastructure for one MANTIS Pilot. The methodology is based on a follow-up study, which is jointly carried with the client, as well as within the scope of the implementation of the ADIRA Pilot. The macro phases that are followed in the present work are: 1) detailed analysis of the business needs; 2) preparation of the architecture specification; 3) implementation/development; 4) tests and validation; 5) support; 6) stabilization; 7) corrective and evolutionary maintenance; and 8) final project analysis and corrective measures to be applied in future projects. The expected results of the development of such project are related to the integration of the industrial maintenance process, to the continuous monitoring of the machines and to the application of advanced techniques of preventive and proactive maintenance of industrial machines, particularly based on techniques and good practices of the Software Engineering area and on the integration of Cyber-Physical Systems.O potencial desenvolvido pela Indústria 4.0 dotará a indústria nacional de capacidades para desenvolver todo o tipo de procedimentos, especialmente a nível da diferenciação competitiva. As perspetivas e as motivações por detrás da Indústria 4.0 estão relacionadas com uma gestão essencialmente direcionada para a internet industrial, com uma análise integrada e utilização de dados, com a digitalização de produtos e de serviços, com novos modelos disruptivos de negócio e com uma cooperação horizontal no âmbito da cadeia de valor. É através da integração dos sistemas ciber-físicos no processo de manutenção que é possível proceder a um monitoramento contínuo das máquinas, tal como à aplicação de técnicas avançadas para a manutenção preditiva e pró-ativa das mesmas. O presente trabalho é baseado no projeto MANTIS, objetivando, portanto, a construção de uma plataforma específica para a manutenção pró-ativa das máquinas industriais, neste caso em concreto das prensas, que serão as máquinas industriais analisadas ao longo do presente trabalho. Dito de um outro modo, objetiva-se, através de uma plataforma em específico, reduzir todos os custos da sua manutenção, aumentando, portanto, os lucros industriais advindos da produção. Resumidamente, o projeto MANTIS consiste num projeto de investigação multinacional, onde a Unidade de Investigação CISTER desenvolve um papel fundamental, particularmente no fornecimento da infraestrutura de comunicação no Piloto MANTIS. A metodologia adotada é baseada num estudo de acompanhamento, realizado em conjunto com o cliente, e no âmbito da implementação do Piloto da ADIRA. As macro fases que são compreendidas por esta metodologia, e as quais serão seguidas, são: 1) análise detalhada das necessidades de negócio; 2) preparação da especificação da arquitetura; 3) implementação/desenvolvimento; 4) testes e validação; 5) suporte; 6) estabilização; 7) manutenção corretiva e evolutiva; e 8) análise final do projeto e medidas corretivas a aplicar em projetos futuros. Os resultados esperados com o desenvolvimento do projeto estão relacionados com a integração do processo de manutenção industrial, a monitorização contínua das máquinas e a aplicação de técnicas avançadas de manutenção preventiva e pós-ativa das máquinas, especialmente com base em técnicas e boas práticas da área de Engenharia de Software

Measures from complexity science provide manufacturing companies with insights previously unavailable to them

"Operational effectiveness" is the means by which market leading value propositions are delivered to customers. The contribution of "operational effectiveness" in manufacturing to competitive strategy has been established. The "operational effectiveness" approach has been based on scientific reductionism, defining itself by list of "best practice" tools, techniques and philosophies. This thesis argues that this had led to loss of the "operational effectiveness" whole, causing variegated success in application of these tools. Complex systems SCience, with its origins in communications, control theory and non-linear dynamical systems, has provided previously unavailable insight into real-world systems. The applications to date in manufacturing have been in soft systems appearing either as metaphors or computationally difficult optimisation-type problems. This thesis argues that manufacturing companies are complex systems. As a result measures for complex behaviour and structure in these systems will yield fresh insight currently unavailable through the reductionist worldview of "operational effectiveness". This research proposes a new framework of agents that connects the "operational effective" and complex systems views, without the loss of system richness of the complexity worldview. This framework comprises interrelated sets of input/output Entities, produced through Activities carried out by Resources. Novel measures of flow efficacy and the structure of these set-based relationships are then obtained based on this common framework by the use of Entropy and QanalYSis respectively. A methodology for the creation of the framework, its measurement and validation is then proposed and tested. Three case studies have been carried out in the actual processes of a manufacturing company. The studies have been able to show a consistent benefit from the use of complexity-based measures over and above what would have been available from "operational effectiveness. Correlation and independence have been observed in the concurrent use of both complexity measures on the frameworks, demonstrating their independence and interdependence

Scheduling research in multiple resource constrained job shops: a review and critique

Over the past several years, a number of survey, classification, and review articles have focused on scheduling research in machine [only] constrained job shops. Barring the work of Treleven (1989), there is no reported research that presents a detailed review of the issues related to scheduling and sequencing in job shops with multiple resource constraints. In his article, Treleven reviewed the research in job shops constrained by machines and labour. Job shops are not only constrained by machines and labour, but by auxiliary resources (in the form of tooling. etc.) as well. This paper extends the work of Treleven by reviewing the literature on scheduling in job shops constrained by more than one resource and comparing the scheduling research in auxiliary resource-constrained job shops with that of labour-constrained job shops. In addition, this article raises some issues for future scheduling research in multiple resource-constrained job shops

A framework for flexible integration in robotics and its applications for calibration and error compensation

Robotics has been considered as a viable automation solution for the aerospace industry to address manufacturing cost. Many of the existing robot systems augmented with guidance from a large volume metrology system have proved to meet the high dimensional accuracy requirements in aero-structure assembly. However, they have been mainly deployed as costly and dedicated systems, which might not be ideal for aerospace manufacturing having low production rate and long cycle time. The work described in this thesis is to provide technical solutions to improve the flexibility and cost-efficiency of such metrology-integrated robot systems. To address the flexibility, a software framework that supports reconfigurable system integration is developed. The framework provides a design methodology to compose distributed software components which can be integrated dynamically at runtime. This provides the potential for the automation devices (robots, metrology, actuators etc.) controlled by these software components to be assembled on demand for various assembly applications. To reduce the cost of deployment, this thesis proposes a two-stage error compensation scheme for industrial robots that requires only intermittent metrology input, thus allowing for one expensive metrology system to be used by a number of robots. Robot calibration is employed in the first stage to reduce the majority of robot inaccuracy then the metrology will correct the residual errors. In this work, a new calibration model for serial robots having a parallelogram linkage is developed that takes into account both geometric errors and joint deflections induced by link masses and weight of the end-effectors. Experiments are conducted to evaluate the two pieces of work presented above. The proposed framework is adopted to create a distributed control system that implements calibration and error compensation for a large industrial robot having a parallelogram linkage. The control system is formed by hot-plugging the control applications of the robot and metrology used together. Experimental results show that the developed error model was able to improve the 3 positional accuracy of the loaded robot from several millimetres to less than one millimetre and reduce half of the time previously required to correct the errors by using only the metrology. The experiments also demonstrate the capability of sharing one metrology system to more than one robot