| 1. |
- Alhusin Alkhdur, Abdullah, 1980-
(författare)
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Toward a Sustainable Human-Robot Collaborative Production Environment
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This PhD study aimed to address the sustainability issues of the robotic systems from the environmental and social aspects. During the research, three approaches were developed: the first one an online programming-free model-driven system that utilises web-based distributed human-robot collaboration architecture to perform distant assembly operations. It uses a robot-mounted camera to capture the silhouettes of the components from different angles. Then the system analyses those silhouettes and constructs the corresponding 3D models.Using the 3D models together with the model of a robotic assembly cell, the system guides a distant human operator to assemble the real components in the actual robotic cell. To satisfy the safety aspect of the human-robot collaboration, a second approach has been developed for effective online collision avoidance in an augmented environment, where virtual three-dimensional (3D) models of robots and real images of human operators from depth cameras are used for monitoring and collision detection. A prototype system is developed and linked to industrial robot controllers for adaptive robot control, without the need of programming by the operators. The result of collision detection reveals four safety strategies: the system can alert an operator, stop a robot, move away the robot, or modify the robot’s trajectory away from an approaching operator. These strategies can be activated based on the operator’s location with respect to the robot. The case study of the research further discusses the possibility of implementing the developed method in realistic applications, for example, collaboration between robots and humans in an assembly line.To tackle the energy aspect of the sustainability for the human-robot production environment, a third approach has been developed which aims to minimise the robot energy consumption during assembly. Given a trajectory and based on the inverse kinematics and dynamics of a robot, a set of attainable configurations for the robot can be determined, perused by calculating the suitable forces and torques on the joints and links of the robot. The energy consumption is then calculated for each configuration and based on the assigned trajectory. The ones with the lowest energy consumption are selected.
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| 2. |
- Andersson, Oscar, 1968-
(författare)
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Digital process planning of joining by numerical models in the automotive industry
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The automotive industry is striving towards reduction of greenhouse gas emission by reducing product weight and improving fuel efficiency of their products. The introduction of lightweight materials have imposed greater pressure not only on the product development but also on manufacturing systems. One integral aspect of manufacturing systems, which is meeting these challenges is joining technology. In order to achieve successful joining of new automotive products, joining process planning must be equally successful.This research aims at improving process planning of joining by introducing digital tools into the process planning work method. The digital tools are designed to reduce lead times and increase accuracy of the process planning to realize more advanced, complex and environmentally friendly product solutions in the vehicles of the future.The research has two main focuses. Firstly, the joining process planning structure and organization have been analysed. The analysis has identified specific instances where digital tools can be introduced to improve the process planning and make it more efficient. Digital tools, such as numerical models for prediction and databases for re-use of knowledge, have been suggested for the process planning. An assessment of the impact of the introduction of these tools in an industrial test case has been performed to show the possible reduction in lead times.Secondly, geometrical distortions due to laser beam welding have been investigated, both by experimental trials and numerical modelling. The influences of design and process parameters on the distribution and magnitude of geometrical distortions have been established. Numerical models of different modelling detail and complexity have been developed and evaluated in order to find modelling approaches with reduced computation times aimed at industrial implementation. The predictive accuracy and computational efficiency of the numerical models have been assessed and evaluated with regard to industrial implementation.
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| 3. |
- Daemi, Bita, 1982-, et al.
(författare)
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Analysis of camera image repeatability using manual and automatic lenses
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Autofocus lenses are conveniently used for applications such as video metrology. In this study we investigate the stability of capturing images and show that for precision metrology applications the autofocus lenses are not as accurate as manual lenses. The investigation was done by analyzing series of seven repeated images captured from a highly accurate reference artifact using two different lenses; autofocus and manual, mounted on a same camera system.
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| 4. |
- Daemi, Bita, 1982-, et al.
(författare)
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Performance evaluation of a micro screen printing installation
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Micro- and nano-manufacturing is an expanding industry and many different manufacturing techniques are used, from advanced focused ion beam treatment to reasonably simple printing technologies. Common to all of them are the needs to verify the manufactured geometries and dimensions. This report presents the results of the second round of benchmarking activities within the EUMINAfab European Research Infrastructure, in order to establish more knowledge about the capabilities of a screen printing installation. To obtain a better understanding of the accuracy of the screen printing installation, a precise verification test is needed to measure the absolute performance of the machine. Predicted performance and capability information is based on specifications given for the machine installation by the machine deliverer. But, in practice the absolute performances of the installation is often off from the specification. When forming the EUMINAfab infrastructure consortium it was decided that independent high precision verification tests should be made on different installations to help the micro-manufacturers to get the real capability information of their equipment and be able to improve performance to a higher EUMINAfab level. In this study a comprehensive verification test was designed and carried out by using an ultra-precision metrology method in order to establish more knowledge about the capabilities of the screen printing equipment. The measurement results show the machine’s X,Y position accuracy, pseudo-repeatability and reproducibility. It is not as good as predicted.
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| 5. |
- Dias-Ferreira, João, 1986-
(författare)
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Bio-Inspired Self-Organising Architecture for Cyber-Physical Manufacturing Systems
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The refinement in consumer's requirements and the fast paced development of socio-technical systems, are promoting, increasingly globalized markets with a high demand for fast time-to-market, sustainable, high quality and highly customized, or even personalized, low priced products. This new reality is forcing companies to change and adapt their business strategies, so that they can quickly and efficiently engage in short-window business opportunities. A critical enabler of the companies' ability to tackle these opportunities is the shopfloor and its ability to cope with change. In this sense, a number of modern manufacturing paradigms emerged, that propose a relaxation of the strictness of the control chains and new modular system designs, that tolerate a controlled and regulated unpredictability of the system behaviour, and simultaneously foster the system's autonomy, robustness, adaptability, plug-ability, evolution and self-organisation.From a structural and dynamic perspective such solutions become, therefore, close to biological systems. In fact, biological systems and their characteristics are a common analogy to express the high level design principles, of modern production paradigms. However, despite this common source of inspiration, the application of bio-inspired concepts, is often lost due to design and implementation choices, or is simply limited to heuristic approaches, that solve specific hard optimization problems.In this dissertation, a bio-inspired reference architecture for production systems, focused on highly dynamic environments, denominated "BIO-inspired Self-Organising ARchitecture for Manufacturing systems" (BIOSOARM), is presented. BIOSOARM was developed under the umbrella of Evolvable Production Systems (EPS) and aims to strictly adhere to bio-inspired principles. For this purpose, both shopfloor components and product parts are individualized and extended into the virtual environment, as fully decoupled autonomous entities, where they interact, following bio-inspired patterns, and cooperate towards the emergence of a self-organising behaviour, that leads to the emergence of the necessary production flows and consequently of the desired products. BIOSOARM, therefore, introduces a fundamentally novel approach to production, that decouples the system's operation from eventual changes, uncertainty or even critical failures, while simultaneously ensures the performance levels and simplifies the deployment, reconfiguration/adaptation and evolution procedures, enabling companies to cope with the new highly dynamic and challenging environments.
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| 6. |
- Mikler, Jerzy, 1958-
(författare)
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On Improvement Of Maintenance Function : A Reference Model And Improvement Methodology
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In order to produce products and services, companies are using various tangible assets such as production equipment and facilities. The goal of the maintenance function is to maintain these assets so they operate safely, efficiently and economically. This function includes technical, administrative and management activities, carried out in order to keep company’s assets in a state, or restore these to a state, in which they can perform the required functions. The activities should be planned and carried out in a way that allows for obtaining the required technical condition, availability, meets the safety requirements for humans and the environment, ensures quality of delivered products and services, and secures the anticipated service life of individual devices. Both effectiveness and efficiency of the maintenance function are very important to each company trying to operate with profit.As follows from the recent research, the performance of maintenance functions in most of the studied companies around the world is in general unsatisfactory, and the underlying reasons of the subnormal behavior are not sufficiently identified, understood and described. The result of research presented in this thesis is an improvement support system based on an explanatory model of the maintenance function. This model shows the mechanisms interconnecting the motivations, intents and rationale behind the involved actors, entities and maintenance activities, and in this way gains understanding of how, and in what way the total performance of the maintenance function is affected, thereby supporting improvement decisions.As maintenance cost is a sharply increasing part of the operational costs, it is an evident target for operational and managerial improvement. This research area is strongly encouraged by industry, and is becoming a topic of increasing interest in the academia.
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| 7. |
- Neves, Pedro
(författare)
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Reconfiguration Methodology to improve the agility and sustainability of Plug and Produce Systems
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The emergence of globalisation, market turbulence and sustainability requirements is challenging production companies to devise new strategies to offer large product diversity, keep low inventories, and timely produce small batches of customised and personalised products. Agile shop-floors that can be promptly deployed and re-configured with minimum integration and programming efforts are perceived as a promising strategy to tackle this problem.This has led to the advent of the Plug and Produce (P&P) concept, where different production modules can be plugged in the system and start working autonomously without ceasing production. P&P systems support structure and functionality transformations through plug/unplug of modules, and dynamic production and fault-tolerance through self-organization. This will naturally increase its complexity in design, operation and exact performance predictability, and therefore it sets the need for the definition of methodologies and decision supporting tools that can help system designers and production managers deciding which layouts and configurations could accommodate constantly changing production requirements (i.e. different product plans and volumes). This thesis focuses exactly on those points, aiming at providing a reconfiguration methodology that can contribute to the increase of agility and sustainability of P&P systems.This methodology enables the systematic generation and assessment of reconfiguration alternatives for P&P systems. For this purpose, it uses graph theory and a set of metrics to assess the potential performance of different reconfiguration alternatives. The experimental tests provided present evidence that the use of the proposed methodology can help designers selecting a suitable reconfiguration alternative whenever new product requirements are posed. The use of this methodology can therefore increase the agility and sustainability of P&P systems and potentially contribute to their industrial deployment.
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| 8. |
- Pervaiz, Salman
(författare)
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Numerical and Experimental Investigations of the Machinability of Ti6AI4V : Energy Efficiency and Sustainable Cooling/ Lubrication Strategies
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Titanium alloys are widely utilized in the aerospace, biomedical,marine, petro-chemical and other demanding industries due to theirdurability, high fatigue resistance and ability to sustain elevateoperating temperature. As titanium alloys are difficult to machine, dueto which machining of these alloys ends up with higher environmentalburden. The industry is now embracing the sustainable philosophy inorder to reduce their carbon footprint. This means that the bestsustainable practices have to be used in machining of titanium alloys aswell as in an effort to reduce the carbon footprint and greenhouse gas(GHG) emissions.In this thesis, a better understanding towards the feasibility of shiftingfrom conventional (dry and flood) cooling techniques to the vegetableoil based minimum quantity cooling lubrication (MQCL) wasestablished. Machining performance of MQCL cooling strategies wasencouraging as in most cases the tool life was found close to floodstrategy or sometimes even better. The study revealed that theinfluence of the MQCL (Internal) application method on overallmachining performance was more evident at higher cutting speeds. Inaddition to the experimental machinability investigations, FiniteElement Modeling (FEM) and Computational Fluid Dynamic (CFD)Modeling was also employed to prediction of energy consumed inmachining and cutting temperature distribution on the cutting tool. Allnumerical results were found in close agreement to the experimentaldata. The contribution of the thesis should be of interest to those whowork in the areas of sustainable machining.
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| 9. |
- Shariat Zadeh, Navid
(författare)
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Standardized architectures for information integration and life cycle management in the domain of production engineering
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- While design and management of production systems based on digital models brings benefits, the communication of models comes with challenges since models typically reside in a distributed heterogeneous IT environment using different syntax and semantics. Coping with heterogeneity requires an appropriate integration strategy and methodology. One main paradigm to integrate information and consequently IT-systems is to deploy standardized information models. In particular, ISO 10303 STEP has been endorsed as a suitable standard to exchange a wide variety of product manufacturing data. The representation and integration of product, process and production resources information using different STEP application protocols are well covered and extensively investigated by many researchers. However, the information representation and integration of logical relations of material flow such as product routing, and its integration with factory layout information has been less subject of research focuses. Hence, this thesis first contributes to identifying, describing and clarifying information requirements for an integrated representation of material flow logic and plant layout using the STEP standard.One the other hand, service-oriented IT-tool integration solutions are increasingly deployed for the data and tool interoperability, especially with the evolution of Open Services for Lifecycle Collaboration (OSLC) whose focus is on the linking of data from heterogeneous software tools. OSLC focuses on the integration of the most common concepts across domains. Assuming a loosely coupled distributed architecture of IT-tools and services, OSLC adopts the Linked Data (LD) approach to ensure data consistency across the data sources. Thus the thesis studies the use of OSLC for tool integration and has found that it cannot be practiced independently for all types of integration in the production engineering domain. Therefore, in practice, there should be a combination of the standardized information and linked data approaches to facilitate the integration process. Thus, this thesis investigates the integration applicability of linked data and OSLC, the principles behind them, and criteria to identify where to use which approach. In addition, the thesis explores the synergy between the standardized information and linked data approaches and consequently suggests an approach based on a combination of these.Further, different computer applications in industrial cases were implemented to verify the suggested approaches. Finally the thesis is concluded with a discussion and suggestions for future work.
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