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  • 1.
    Adamsson, Niklas
    KTH, Superseded Departments, Machine Design.
    Model-based development of mechatronic systems — Reducing the gaps between competencies?2004In: Proceedings of TMCE 2004: The fifth international symposium on Tools and Methods of Competitive Engineering / [ed] Horvath I, Xirouchakis P, Rotterdam: MILLPRESS SCIENCE PUBLISHERS , 2004, Vol. 1(2), no 405-414, p. 405-413Conference paper (Refereed)
    Abstract [en]

    This paper presents the results of a multiple case study performed within the Swedish vehicle industry. The objective of the study was to explore and describe how modeling affects collaboration within multidisciplinary product development from the perspective of developers. Most research on mechatronics design is focused on technology and/or is limited to one or a few of the disciplines involved. By contrast, the focus of this study is on collaboration between and integration of different technical disciplines. A total of 21 semi-structured interviews were conducted during a period of five months. The criterion for a valid case was that it concerned a development project including distributed functionality and multidisciplinary teams. The main conclusions are that a higher degree of competence integration is needed as complexity increases, that a mutually agreed language is needed within an organization, that the modeling approach within an organization should be aligned, that the tasks where different technical disciplines meet must be identified in order to achieve early system integration, and that short-term co-locations would increase understanding and problem solving efficiency. This research has many similarities with earlier research performed on integrated product development, hut has a different focus level. Instead of on marketing-manufacturing-R&D, the focus is on the technical disciplines within R&D.

  • 2.
    Agrell, Fredrik
    KTH, Superseded Departments, Machine Design.
    Control of HCCI by aid of variable valve timings2003Licentiate thesis, comprehensive summary (Other scientific)
  • 3.
    Agrell, Fredrik
    et al.
    KTH, Superseded Departments, Machine Design.
    Ångström, Hans-Erik
    KTH, Superseded Departments, Machine Design.
    Eriksson, Bengt
    Wikander, Jan
    KTH, Superseded Departments, Machine Design.
    Linderyd, Johan
    Integrated Simulation and Engine Test of Closed Loop HCCI Control by aid of Variable Valve Timings2003In: SAE transactions, ISSN 0096-736X, Vol. 112, no 3, p. 1078-1091Article in journal (Refereed)
  • 4.
    Agrell, Fredrik
    et al.
    KTH, Superseded Departments, Machine Design.
    Ångström, Hans-Erik
    KTH, Superseded Departments, Machine Design.
    Eriksson, Bengt
    Wikander, Jan
    KTH, Superseded Departments, Machine Design.
    Linderyd, Johan
    Transient Control of HCCI Through Combined Intake and Exhaust Valve Actuation2003Conference paper (Refereed)
    Abstract [en]

    Homogeneous Charge Compression Ignition, HCCI, has the attractive feature of low particulate emission and low Nitrogen Oxides, NOx, emission combined with high efficiency. The principle is a combination of an Otto and a Diesel engine in that a premixed charge is ignited by the compression heat.

  • 5.
    Ahari, Parviz
    KTH, Superseded Departments, Machine Design.
    A living systems approach to product design and development2003Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    Product development is a complex activity that involvespeople with different expertise, financial resources,materials, and machines. Organizations that carry out theseprocesses and their products are in fact living and artificialsystems. The concept of system is therefore very important fordealing with complexity of products, and their developmentprocesses. However, the concept of system is not consideredcarefully and scientifically in this context, therefore itsexplanations in design and development literature havelimitations and do not provide sufficient help for those whoare involved in the complex processes of product design anddevelopment.

    In this research an attempt is made to show the relevance ofsystems concepts for product development. The purpose of thisresearch is therefore to provide knowledge, and betteralternative points of view that helps to manage complexities ofproducts and product development processes, to improveunderstanding of them, to avoid problems related toconventional thinking, and to complement conventionalmethods.

    To provide this knowledge the weaknesses of the conventionalmethods of product development and the strengths ofunconventional systemic methods have been shown. Systemsthinking as an unconventional method has been introduced anddiscussed. These presentations include the need for a newscientific method, the meaning of system, its origin, kinds ofsystems, why, and how systems sciences are applied. Further theneed for and importance of a better theory in product designand development is shown. Living systems theory (LST) isintroduced, and explained. LST’s applications in differentdisciplines are presented. The research includes also adiscussion of the meaning of products, their places in livingsystems and what triggers their design and development.

    The importance of creativity, innovation, and lifelonglearning are emphasized and discussed. It has been shown howliving systems theory and other systems sciences can contributeto them. The relevance of how we see the world is discussed andit has been shown how we can and should improve our way ofseeing the world. It has also been shown that information andknowledge are not sufficient. We should also become wiser, andthis requires consideration of the long-term consequences ofour actions and it involves values and judgment.

    The results of this research are both descriptive andprescriptive. They provide several contributions, for example,a systemic cube (table) of artifacts (analogous withMendeleyev’s table of elements) as a model for managingcomplexity and for generating creative ideas; and a new conceptof usability engineering, which has been applied in industry indifferent projects. Further a more complete LST based model,which can be used for products and product developmentprocesses (for living and artificial systems), has beenprovided. The research uncovers also neglected aspects of LSTin product design and development and shows how they can beconsidered, these are for example the concepts of alpha- beta-,and gamma-coded information. It has also been shown how we canacquire a more complete understanding of product developmentactivities and how we can improve these processes. Thesecontributions have both academic and industrial relevance andpresent a step in the right direction–improving thequality of life.

    Keywords:Product design and development, living systemstheory, needs, managing complexity, modeling, systems thinking,problem solving, creativity, lifelong learning.

  • 6.
    Andersson, Kjell
    KTH, Superseded Departments, Machine Design.
    A REQUIREMENT-DRIVEN PRODUCT DEVELOPMENT PROCESS2004In: 7th Workshop on Product Structuring: Product platform Development / [ed] J. Malmqvist, 2004, p. 37-48Conference paper (Refereed)
    Abstract [en]

    Product development is often described as an iterative process of finding solutions that match specific requirements. The many dimensions of this process include time, organization, product-specific elements such as the level of abstraction and detail, and analysis to verify the product’s properties.

    Many types of software tools are used to generate and visualize the concept shape. These include CAD (computer-aided design) tools; tools to simulate and verify product properties, such as FE (finite element analysis) and MBS (multibody systems); and tools for handling product data such as PDM (product data management). This paper focus on the effective use of simulation software such as FE and MBS tools to support the process of verifying that a product meets the formulated requirements. The simulation software can be used for such things as selecting alternative solutions or as a final check or optimization of a solution concept. Its can be used even more effectively if it is supported by a framework for handling the information created during the verification process.

    This paper presents a proposal for an information framework that can support traceability and reuse of partial results created during the verification of a specific required attribute. This framework also facilitates study of the effects of changes in the specification on product properties. The framework is illustrated in a modeling and simulation scenario for a lifting unit on a wheel loader produced by Volvo CE. This scenario focus on modeling and simulation activities and how these can be supported in a question-and-answer driven process that investigates the behavior of the lifting unit. 

  • 7.
    Andersson, Kjell
    KTH, Superseded Departments, Machine Design.
    An iterative question-answer driven process to support product design2004In: PROCEEDINGS OF NORDDESIGN 2004: PRODUCT DEVELOPMENT IN CHANGING ENVIRONMENT / [ed] Lehtonen, T, TAMPERE: TAMPERE UNIV TECH PRODUCT DEVELOPMENT LABORATORY , 2004, p. 173-182Conference paper (Refereed)
    Abstract [en]

    Product development is often described as an iterative process of finding solutions that match specific requirements. The many dimensions of this process include time, organization, product-specific elements such as the level of abstraction and detail, and analysis to verify the product's properties. Many types of software tools are used to generate and visualize the concept shape. These include CAD (computer-aided design) tools; tools to simulate and verify product properties, such as FE (finite element analysis) and MBS (multibody systems); and tools for handling product data such as PDM (product data management). This paper focus on the effective use of simulation software such as FE and MBS tools to support the process of verifying that a product meets the formulated requirements. The simulation software can be used for such things as selecting alternative solutions or as a final check or optimization of a solution concept. Its can be used even more effectively if it is supported by a framework for handling the information created during the verification process. This paper presents a proposal to a question-answer driven process for verification of product requirements. This process is based on the framework presented by the author in [Andersson 2004a, 2004b]. The process is illustrated in a modeling and simulation scenario of a lifting unit in a wheel loader from Volvo CE. This scenario focus on modeling and simulation activities and how these can be supported in a question-answer driven process that investigates the behavior of the lifting unit.

  • 8.
    Andersson, Kjell
    KTH, Superseded Departments, Machine Design.
    Simulation in product design: An iterative question-answer driven process2004In: Design 2004: Proceedings of the 8th International Design Conference, Vols 1-3 / [ed] Marjanovic, D, 2004, p. 91-98Conference paper (Refereed)
  • 9.
    Bernemyr, Hanna
    et al.
    KTH, Superseded Departments, Machine Design.
    Ångström, Hans-Erik
    KTH, Superseded Departments, Machine Design.
    Ström, Johan
    Stockholms Universitet.
    Hansson, Hans-Christen
    Stockholms Universitet.
    Study of Particulate Emissions from Heavy-Duty Diesel Engines using a Rotating Disc Diluter and a Volatility Tandem DMA (v-TDMA)2004Conference paper (Refereed)
  • 10. Beskow, C.
    et al.
    Ritzén, Sofia
    KTH, Superseded Departments, Machine Design.
    Performing changes in product development: A framework with keys for industrial application2000In: Research in Engineering Design, ISSN 0934-9839, E-ISSN 1435-6066, Vol. 12, no 3, p. 172-190Article in journal (Refereed)
    Abstract [en]

    Industrial product development requires continuous improvements in work procedures as a result of constantly changing demands. Support tools have proven to be an oft chosen way to meet new demands; however. few research efforts have been made in how to implement new tools. This article is a contribution to knowledge on carrying out the implementation of support tools. The basis consists of four field studies performed during 1994-1999, containing 78 qualitative research interviews and focusing on the implementation and use of different support tools. A re-analysis has been performed of selected interviews from the field studies. in total 30 interviews. This resulted in recommendations for an implementation framework, consisting of an Implementation Cycle, Organizational Change Field and Managerial Consistence, and five implementation keys: Goal setting, Kowledge Development, Anchoring at All Levels, Suitable Resources and Focus on the Individual.

  • 11.
    Beskow, Cecilia
    KTH, Superseded Departments, Machine Design.
    Product development in change: Cross-functional Co-operation and PDM implementations2001Licentiate thesis, comprehensive summary (Other scientific)
  • 12.
    Beskow, Cecilia
    KTH, Superseded Departments, Machine Design.
    Towards a higher efficiency2000Doctoral thesis, comprehensive summary (Other scientific)
  • 13.
    Beskow, Cecilia
    et al.
    KTH, Superseded Departments, Machine Design.
    Ritzén, Sofia
    KTH, Superseded Departments, Machine Design.
    Performing Changes in Product Development: an Implementation Framework with Keys2000In: Journal of engineering design (Print), ISSN 0954-4828, E-ISSN 1466-1837, Vol. 12, no 3, p. 172-190Article in journal (Refereed)
    Abstract [en]

    Industrial product development requires continuous improvements in work procedures as a result of constantly changing demands. Support tools have proven to be an oft chosen way to meet new demands; however, few research efforts have been made in how to implement new tools. This article is a contribution to knowledge on carrying out the implementation of support tools. The basis consists of four field studies performed during 1994–1999, containing 78 qualitative research interviews and focusing on the implementation and use of different support tools. A re-analysis has been performed of selected interviews from the field studies, in total 30 interviews. This resulted in recommendations for an implementation framework, consisting of an Implementation Cycle, Organizational Change Field and Managerial Consistence, and five implementation keys: Goal setting, Kowledge Development, Anchoring at All Levels, Suitable Resources and Focus on the Individual.

  • 14.
    Björklund, Stefan
    KTH, Superseded Departments, Machine Design.
    The influence of surface roughness in elliptical contacts2001In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 34, no 12, p. 841-845Article in journal (Refereed)
    Abstract [en]

    The influence of surface roughness on contact behaviour is of great importance in many tribological situations. In the last decade several methods to calculate the pressure distribution and the real contact area in contacts between rough surfaces have been described. A problem arising for slender elliptical contacts, such as between gear teeth, roller and raceway, cam and follower, etc., is that the size of the contact is much greater than the size of the asperities. Accordingly the number of contact nodes necessary for an accurate solution to the problem becomes excessively large. This paper describes a method to calculate the influence of three-dimensional surface roughness in contacts that are very long in one direction. The method is based on restricting the calculations to a subpart of the real contact area, while the rest of the contact is taken into account by mirroring techniques. The results show that the real contact area is very sensitive to the amplitude of the roughness, while the waviness is less important. An equation is suggested from which the real area can be calculated if the smooth case contact parameters and two roughness parameters are known.

  • 15.
    Blackenfelt, Michael
    KTH, Superseded Departments, Machine Design.
    Managing complexity by product modularisation2001Doctoral thesis, comprehensive summary (Other scientific)
  • 16.
    Blackenfelt, Michael
    KTH, Superseded Departments, Machine Design.
    On the development of modular mechatronic products1999Licentiate thesis, comprehensive summary (Other scientific)
  • 17.
    Brauer, Jesper
    KTH, Superseded Departments, Machine Design.
    A general finite element model of involute gears2004In: Finite elements in analysis and design (Print), ISSN 0168-874X, E-ISSN 1872-6925, Vol. 40, no 13-14, p. 1857-1872Article in journal (Refereed)
    Abstract [en]

    Involute gears comprise primarily spur gears, helical gears, straight conical involute gears and conical involute gears. Robust and effective parameterised finite element models of involute gears should be based on analytically derived mathematical representations of their shape. In this paper we derive a mathematical description of conical involute gears that is also capable of representing three other types of involute gear. The equations and the intervals for the surface parameters are then used to create a general finite element model of involute gears.

  • 18.
    Brauer, Jesper
    KTH, Superseded Departments, Machine Design.
    Investigation of transmisison error, friction and wear in anti-backlash involute gear transmissions2003Doctoral thesis, comprehensive summary (Other scientific)
  • 19.
    Brauer, Jesper
    KTH, Superseded Departments, Machine Design.
    Towards a dynamic model of a cronical involute gear transmission2000Licentiate thesis, monograph (Other scientific)
  • 20.
    Bäckman, Jon
    KTH, Superseded Departments, Machine Design. KTH, Superseded Departments, Industrial Economics and Management.
    Kommer svenska högavkastande företagsobligationer att bli ett vanligare placeringsalternativ i Sverige?2012Student paper other, 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Marknadsförutsättningarna för en utveckling av den svenska marknaden för högavkastande företagsobligationer är idag bättre än någonsin. För första gången är bankerna motiverade att hjälpa svenska företag med marknadsfinansiering via exempelvis företagsobligationer. Tidigare har denna verksamhet setts som konkurrerande till bankernas egen lånefinansiering. Regulatoriska förändringar, såsom Basel III, ligger till grund för denna nya viktiga förutsättning.

     

    Det händer saker på bred front och mycket sker samtidigt. Nya aktörer och organisationer har bildats, färdiga marknadsplatser för högavkastande företagsobligationer finns nu att tillgå. Fler regulatoriska förändringar har skett och kommer att ske framöver. Syftet med dessa regulatoriska förändringar är bland annat att förbättra transparensen på markanden och öka intresset för ränteplaceringar som alternativ till aktieplaceringar för vissa institutionella investerare.

     

    Rapportens resultat motiverar en utveckling av den svenska marknaden för högavkastande företagsobligationer, med fler emittenter och fler emitterade instrument. Den uteblivna avkastningen och det volatila beteendet av den svenska aktiemarknaden de sista 12 åren, motiverar investerare att se sig om efter alternativa placeringar. När marknadsräntorna är rekordlåga blir företagsobligationer ett mycket intressant alternativ.

     

    Kunskapsnivåerna behöver dock höjas både hos framtida potentiella emittenter och hos investerare. Större resurser hos befintliga intermediärer och kanske fler aktörer kommer att krävas för att klara av det ökade behovet av obligationsfinansiering hos de svenska företagen. Fler emitterade instrument och en bättre transparens på marknaden kommer att ge investerare bättre möjligheter att utvärdera förväntad avkastning och de risker som finns förknippade med detta placeringsalternativ.

     

    Huruvida högavkastande företagsobligationer kommer att bli ett framtida sparalternativ för svenska sparare är lite osäkrare. Fler emissioner av högavkastande företagsobligationer tros komma redan den närmaste tiden, medan det kan ta längre tid för den nya potentiella sparformen att etablera sig bland investerare. En ökning av detta placeringsalternativ hos svenska sparare kommer förmodligen att ske succesivt, men i vilken mån denna sparform på sikt etablerar sig återstår att se.

  • 21. Bäckmar, J
    et al.
    Ritzén, Sofia
    KTH, Superseded Departments, Machine Design.
    Norell, Margareta
    Environmentally Friendly Product Development: Activities in Industrial Companies1998In: IEEE EMS International Engineering Management Conference, May 3-5, 1998, San Juan, Puerto Rico, 1998, p. 502-507Conference paper (Other academic)
  • 22. Bäckmar, J
    et al.
    Ritzén, Sofia
    KTH, Superseded Departments, Machine Design.
    Norell, Margareta
    Implementation of Environmental Management Systems in Swedish Industry1999In: Proceedings from 1st International Symposium on Environmentally Conscious Design and Inverse Manufacturing: EcoDesign 99, February 1-3, Tokyo, Japan, 1999, p. 539-544Conference paper (Other academic)
  • 23.
    Bäckmar, Johan
    KTH, Superseded Departments, Machine Design.
    Strategies for sustainable product development: managing the challenge2000Licentiate thesis, comprehensive summary (Other scientific)
  • 24.
    Chen, DeJiu
    KTH, Superseded Departments, Machine Design.
    Architecture for Mechatronics Software Systems: A Survey of Related Concepts1999Report (Other academic)
    Abstract [en]

    One promising approach to managing complexity and ensuring qualities of software systems is through software architecture, denoting the science and art of software structuring. In this report, some important concepts, theories, and methods of software architecture from software engineering will be studied. Since these technologies are developed with generic software applications in mind, there is generally a lack of support for many important aspects of embedded computer control, such as timing and constrained resources. This has limited the potential benefits of exploiting architecture-based reasoning in the development of embedded control software. Future research should focus on integrating embedded computer control specific semantics and implementation constraints with these general technologies.

  • 25.
    Chen, De-jiu
    KTH, Superseded Departments, Machine Design.
    Architecture for systematic development of mechatronics software systems2001Licentiate thesis, monograph (Other scientific)
  • 26.
    Chen, Dejiu
    KTH, Superseded Departments, Machine Design.
    Systems Modeling and Modularity Assessment for Embedded Computer Control Applications2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    AbstractThe development of embedded computer control systems(ECS) requires a synergetic integration of heterogeneoustechnologies and multiple engineering disciplines. Withincreasing amount of functionalities and expectations for highproduct qualities, short time-to-market, and low cost, thesuccess of complexity control and built-in flexibility turn outto be one of the major competitive edges for many ECS products.For this reason, modeling and modularity assessment constitutetwo critical subjects of ECS engineering.In the development ofECS, model-based design is currently being exploited in most ofthe sub-systems engineering activities. However, the lack ofsupport for formalization and systematization associated withthe overall systems modeling leads to problems incomprehension, cross-domain communication, and integration oftechnologies and engineering activities. In particular, designchanges and exploitation of "components" are often risky due tothe inability to characterize components' properties and theirsystem-wide contexts. Furthermore, the lack of engineeringtheories for modularity assessment in the context of ECS makesit difficult to identify parameters of concern and to performearly system optimization.

    This thesis aims to provide a more complete basis for theengineering of ECS in the areas of systems modeling andmodularization. It provides solution domain models for embeddedcomputer control systems and the software subsystems. Thesemeta-models describe the key system aspects, design levels,components, component properties and relationships with ECSspecific semantics. By constituting the common basis forabstracting and relating different concerns, these models willalso help to provide better support for obtaining holisticsystem views and for incorporating useful technologies fromother engineering and research communities such as to improvethe process and to perform system optimization. Further, amodeling framework is derived, aiming to provide a perspectiveon the modeling aspect of ECS development and to codifyimportant modeling concepts and patterns. In order to extendthe scope of engineering analysis to cover flexibility relatedattributes and multi-attribute tradeoffs, this thesis alsoprovides a metrics system for quantifying componentdependencies that are inherent in the functional solutions.Such dependencies are considered as the key factors affectingcomplexity control, concurrent engineering, and flexibility.The metrics system targets early system-level design and takesinto account several domain specific features such asreplication and timing accuracy.

    Keywords:Domain-Specific Architectures, Model-basedSystem Design, Software Modularization and Components, QualityMetrics.

  • 27.
    Chen, DeJiu
    et al.
    KTH, Superseded Departments, Machine Design.
    El-Khoury, Jad
    KTH, Superseded Departments, Machine Design.
    Törngren, Martin
    KTH, Superseded Departments, Machine Design.
    A Modeling Framework for Automotive Embedded Control Systems2004Conference paper (Refereed)
    Abstract [en]

    This work is part of a larger effort to define a modeling approach suitable for complex embedded control systems for which modeling techniques are in the progress of maturing. Modeling constitutes an indispensable part of engineering, forming an important basis for documentation, communication, and design automation. In order to describe and compare different modeling techniques, a framework has been developed. The current state of the framework is presented together with lessons learned. We will illustrate the framework with an automotive application. The framework combines a generic concept of systems and the modeling concepts that have been extracted from a study of 12 modeling approaches covering different levels of design and disciplines. Future work will refine the framework by studying additional modeling techniques and by considering more domain specific modeling needs in automotive systems.

  • 28.
    Chen, DeJiu
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Embedded Control Systems.
    Törngren, Martin
    KTH, Superseded Departments, Machine Design.
    A metrics system for quantifying operational coupling in embedded computer control systems2004In: Proceedings of the 4th ACM international conference on Embedded software, 2004, p. 184-192Conference paper (Refereed)
    Abstract [en]

    One central issue in system structuring and quality prediction is the interdependencies of system modules. This paper proposes a novel technique for determining the operational coupling in embedded computer control systems. It allows us to quantify dependencies between modules, formed by different kinds of relationships in a solution, and therefore promotes a more systematic approach to the reasoning about modularity. Compared to other existing coupling metrics, which are often implementation-technology specific such as confining to the inheritance and method invocation relationships in OO software, this metrics system considers both communication and synchronization and can be applied throughout system design. The metrics system has two parts. The first part supports a measurement of coupling by considering individual relationship types separately. The quantification is performed by considering the topology of connections, as well as the multiplicity, replication, frequency, and accuracy of component properties that appear in a relationship. The second part provides a methodology for combining coupling by individual relationship types into an overall coupling, where domain specific heuristics and technology constraints are used to determine the weighting.

  • 29.
    Chen, DeJiu
    et al.
    KTH, Superseded Departments, Machine Design.
    Törngren, Martin
    KTH, Superseded Departments, Machine Design.
    A systematic approach for identifying operational relationships in embedded computer control systems2004In: PROCEEDINGS OF THE 30TH EUROMICRO CONFERENCE / [ed] Steinmetz R; Mauthe A, IEEE , 2004, p. 32-39Conference paper (Refereed)
    Abstract [en]

    Embedded computer control systems are a kind of safety critical real-time system, formed by a synergetic integration of various functions, technologies, and engineering disciplines. To modularize the design and to define the embodiments of functional modules in terms of software components, a more precise modeling of systems and support for assessments of modularity and related tradeoffs in designs is necessary. However, little support exists in this area. Existing system models and modularity metrics such as coupling and cohesion are often either too general or too specific by targeting only a specific implementation technology. This paper proposes a meta-level model for the systems and a fine-grained classification of relationship patterns established by communication, synchronization, and implementation. The work emphasizes a system perspective and aims to support a more precise assessment of coupling, considered as one of the most important criterion for component creation and integration as well as structuring.

  • 30.
    Chen, DeJiu
    et al.
    KTH, Superseded Departments, Machine Design.
    Törngren, Martin
    KTH, Superseded Departments, Machine Design.
    Towards A Framework for Architecting Mechatronics Software Systems2001In: Proceedings of 7th IEEE International Conferenceon Engineering of Complex Computer Systems / [ed] Andler, Sten F., Hinchey, Michael G., Offutt, Jeff, Los Alamitos: IEEE Computer Society, 2001, p. 170-179Conference paper (Refereed)
    Abstract [en]

    As mechatronics software systems become larger and more complex, the need to ensure system consistency and completeness with respect to the requirements and to manage system complexity becomes more important. From a system point of view, complexity depends on the number and the multiplicity of system constituent units and their relationships. In this paper, the initial results from our efforts to adopt the concept of software architecture in the development of mechatronics software systems for the purpose of managing complexity and ensuring system qualities are presented. A design framework for architecting mechatronics software systems is being developed. The design framework includes two models: (1) an architecture model, and (2) a decision model. The architecture model aims to provide an effective basis for managing complexity and performing architecture based system development. The decision model aims to provide a basis for reasoning about how to meet flexibility-related qualities in the development.

  • 31.
    Crabo Ljungman, Lisbeth
    KTH, Superseded Departments, Machine Design.
    The front end mess: a model for structured innovation management1998Doctoral thesis, comprehensive summary (Other scientific)
  • 32.
    Cronhjort, Andreas
    KTH, Superseded Departments, Machine Design.
    Droplet Velocities in a Liquid Spray2002Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    A method to look into a dense liquid spray has beenevaluated. The spray was mechanically sliced to remove theobscuring parts of it, thus gaining optical access to theinternal regions and thereby allowing for visualization ofpreviously unavailable parts of the spray. The width of themechanical slit was 100 µm, which was significantlysmaller than earlier experiments performed by otherresearchers. The approach was applied to a diesel fuel spray,and velocities were measured by means of image analysis appliedto double-exposed images of droplets in the spray.

    To perform the evaluation a test rig wasdeveloped, whereliquid sprays could be optically studied under controlledconditions. In the test rig diesel fuel was injected into apressurized vessel with optical access, which was achievedusing two glass windows, one for the light from the flash, andthe other for the camera. The necessary optics and the camerawere fitted on a rail, to allow for easy adjustment of thefocus. Personal computers controlled the injection sequence andthe image acquisition. The injector used was a prototype withan internal hydraulic pressure booster, which deliversapproximately 100 MPa peak injection pressure. The nozzle usedwas a specially manufactured one with an axial orifice, inorder to fit into the available vessel. The diameter of thenozzle orifice was 110 µm, and the orifice length was 700µm. The temperature in the vessel was 300 K and the gaspressure 3 MPa. The gas in the vessel was air, and consequentlythe gas density was about 35 kg/m3.

    Enlarging optics in conjunction with a solid-state camerawas used to acquire the images. The magnification of the opticswas about ten times, the useful resolution 10 µm, and thedepth of field approximately 100 µm. The double-exposureswere achieved in two different ways, in the beginning by meansof a spark discharge flash unit able to deliver multiplesparks, with a flash duration of approximately 300 ns, butlater with the shutter of the camera in combination with axenon discharge flash lamp, to achieve shorter exposure times.The spray was lighted up from behind by the flashlight, andconsequently the droplets were visible as dark regions againsta bright background.

    It was considered convenient to work with an imagevelocimetry software for which the source code was accessible,and for that reason primarily in-house developed codes wereused. Three different velocimetry approaches were evaluated,namely cepstrum, cepstrum with the low frequency pedestalremoved from the intermediate spectrum, and finallyauto-correlation. It was concluded that the most powerfulalgorithm was the cepstrum with pedestal removal. However, thismethod showed significant sensitivity to variations in inputdata, and was therefore rejected. Auto-correlation wasconsidered the most rugged algorithm, and as the images were tobe processed in an automated manner, it was decided thatauto-correlation was to be used.

    In order to make the final algorithm able to discard imagesfrom which it failed to get correct velocity data, a number offilters and thresholds were used. The filter parameters and thethreshold levels were adjusted manually to treat a smallreference group of images correctly before they were applied tothe real data.

    Keywords:Liquid spray, diesel spray, dropletvelocities, droplet sizes, spray visualization, sliced spray,particle image velocimetry, spectrum, cepstrum,cross-correlation, auto-correlation.

  • 33.
    Cronhjort, Andreas
    KTH, Superseded Departments, Machine Design. Scania CV AB.
    Spray Visualization Using a Mechanical Slicing Device2000Conference paper (Refereed)
    Abstract [en]

    This paper describes a concept for gaining photographic access, at a high magnification level, to quite dense regions in liquid sprays, aiming primarily at photographic investigations of the spray and studies of the trailing edge with its associated large droplets. The slicing of the spray is achieved with two sharp edges, which cut out a thin sheet of the spray. The sheet of droplets is visualized with conventional shadow photography. The images acquired with the slicer are compared with images acquired without it, and even though some ligaments are identified as originating from the edges of the slit, the method is still considered as being beneficial, as the quality of the images is significantly enhanced.

  • 34.
    Dahlén, Lars
    KTH, Superseded Departments, Machine Design.
    On applied CFD and model development in combustion systems development for DI diesel engines2002Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Soot mediated oil thickening, normally referred to asoilsoot, is a well known problem that can cause increased wearon lubricated moving or rubbing components in diesel engines.The ambition of this thesis is to understand the mechanisms ofcombustion and soot formation that pave the way for thisproblem and use this knowledge in the development of apredictive model for soot contamination of the oil. Anadditional task, however, is the use of Computational FluidDynamics (CFD) as the platform for development of the oilsootmodel.

    A preliminary hypothesis for soot contamination of the oilis formulated from a combination of theoretical reasoning andprevious experimental evaluations. This states that the oilsootgrowth rate is the result of particle deposition in the oilfilm on the cylinder liner, followed by scraping ofcontaminated oil to the crank case by the piston rings. Acontrolling factor here is assumed to be thermophoresis, whichhas been identified in the past as the dominating particletransport mechanism within the viscous sublayer at combustionchamber surfaces and hence governs the rate of particledeposition in the oil film on the liner.

    A thermophoretic particle deposition model is suggested forthe calculation of soot deposition on the liner from local sootdistribution as predicted by the standard CFD code. The modelis evaluated through parameter studies comprising the influenceof injection timing, liner temperature, topland height,injected fuel quantity, equivalence ratio, boost pressure andspeed, and the agreement between simulations and measurementsis generally good. It is concluded that the peak in-cylindersoot concentration is more important to oilsoot growth than theexhaust soot level. Moreover, changes in in-cylinder sootdistribution has strong effect on soot mediated oil thickening.Consequently, an important practical guideline to reduce sootmediated oil thickening is to end injection“ontime”, i.e. before the spray guided diffusion flame isdirected into the squish region rather than into the pistonbowl.

  • 35.
    Dahlén, Lars
    KTH, Superseded Departments, Machine Design.
    Topics related to combustion and emissions formation in direct injected diesel engines. Vol. 1 Soot mediation oil thickening2000Licentiate thesis, comprehensive summary (Other scientific)
  • 36.
    Dahlén, Lars
    KTH, Superseded Departments, Machine Design.
    Topics related to combustion and emissions formations in direct injected diesel engines. Vol. 2 Heat transfer2000Licentiate thesis, monograph (Other scientific)
  • 37.
    Dizdar, Senad
    KTH, Superseded Departments, Machine Design.
    Formation and failure of boundary layers in mixed and boundary lubricated sliding contacts1997Licentiate thesis, comprehensive summary (Other scientific)
  • 38.
    Dizdar, Senad
    KTH, Superseded Departments, Machine Design.
    Formation and failure of chemireacted boundary layers in lubricated steel contacts1999Doctoral thesis, comprehensive summary (Other scientific)
  • 39.
    Drogou, Raphael
    KTH, Superseded Departments, Machine Design.
    Simulation of the dynamic behavior of modular structures1998Licentiate thesis, monograph (Other scientific)
  • 40.
    During, Carl
    et al.
    KTH, Superseded Departments, Machine Design.
    Andersson, Sören
    KTH, Superseded Departments, Machine Design.
    Wikander, Jan
    KTH, Superseded Departments, Machine Design.
    Non-contact, absolute position measurement,using a compact disc record player optical pick-up1992In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 32, p. 575-581Article in journal (Refereed)
  • 41.
    El-khoury, Jad
    et al.
    KTH, Superseded Departments, Machine Design.
    Chen, DeJiu
    KTH, Superseded Departments, Machine Design.
    Törngren, Martin
    KTH, Superseded Departments, Machine Design.
    A Survey of Modeling Approaches forEmbedded Computer Control Systems2003Report (Other academic)
  • 42.
    Elmqvist, Christel
    et al.
    KTH, Superseded Departments, Machine Design.
    Lindström, Fredrik
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Ångström, Hans-Erik
    KTH, Superseded Departments, Machine Design.
    Grandin, Börje
    Kalghatgi, Gautam
    Optimizing engine concepts by using a simple model for knock prediction2003In: SAE Paper 2003-01-3123, SAE , 2003Conference paper (Refereed)
    Abstract [en]

    The objective of this paper is to present a simulation model for controlling combustion phasing in order to avoid knock in turbocharged SI engines. An empirically based knock model was integrated in a one-dimensional simulation tool. The empirical knock model was optimized and validated against engine tests for a variety of speeds and λ . This model can be used to optimize control strategies as well as design of new engine concepts.

  • 43.
    Eneström, Pia
    KTH, Superseded Departments, Machine Design.
    Buyer-supplier relationships in production development: studies in the aluminiummanufacturing industry2001Licentiate thesis, comprehensive summary (Other scientific)
  • 44.
    Eriksson, Bengt
    et al.
    KTH, Superseded Departments, Machine Design.
    Wikander, Jan
    KTH, Superseded Departments, Machine Design.
    Robust PID design of flexible manipulators through pole assignment2002Conference paper (Refereed)
  • 45.
    Eriksson, Christer
    KTH, Superseded Departments, Machine Design.
    A framework for the design of distributed real-time systems1997Doctoral thesis, comprehensive summary (Other scientific)
  • 46. Flemmer, H.
    et al.
    Eriksson, Bengt
    KTH, Superseded Departments, Machine Design.
    Wikander, Jan
    KTH, Superseded Departments, Machine Design.
    Control design and stability analysis of a surgical teleoperator1999In: Mechatronics - the science of intelligent machines - Int. Journal, Vol. 9, no 7, p. 843-866Article in journal (Refereed)
  • 47.
    Flemmer, Henrik
    KTH, Superseded Departments, Machine Design.
    Analysis of force reflecting control methods for teleoperators with special reference to surgical applications2000Licentiate thesis, comprehensive summary (Other scientific)
  • 48.
    Flemmer, Henrik
    KTH, Superseded Departments, Machine Design.
    Control Design and Performance Analysis of force Reflective Teleoperators - A Passivity Based Approach2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    In this thesis, the problem of controlling a surgical masterand slave system with force reflection is studied. The problemof stiff contacts between the slave and the environment isgiven specific attention. The work has been carried out at KTHbased on an initial cooperation with Karolinska Sjukhuset. Theaim of the over all project is to study the possibilities forintroduction of a force reflective teleoperator in neurologicalskullbase operations for the particular task of bone millingand thereby, hopefully, increase patient safety, decreasesurgeon workload and cost forthe society.

    The main contributions of this thesis are:

    Derivation of a dynamical model of the master andoperator’s finger system and, experimental identificationof ranges on model parameter values. Based on this model, theinteraction channel controllers optimized for transparency arederived and modified to avoid the influence of the uncertainmodel parameters. This results in a three channel structure. Todecrease the influence of the uncertain parameters locally atthe master, a control loop is designed such that the frequencyresponse of the reflected force is relatively unaffected by theuncertainties, a result also confirmed in a transparencyanalysis based on the H-matrix. The developed teleoperatorcontrol structure is tested in experiments where the operatorcould alter the contact force without facing any problems aslong as the slave is in contact with the environment.

    As a result of the severe difficulties for the teleoperatorto move from free space motion to in-contact manipulationwithout oscillative behaviour, a new detection algorithm basedon passivity theory is developed. The algorithm is able todetect the non-passive behaviour of the actual teleoperatorinduced by the discrete change in system dynamics occurring atthe contact instant. A stabilization controller to be activatedby the detection algorithm is designed and implemented on themaster side of the teleoperator. The detection algorithm andthe stabilization controller are shown highly effective in realexperiments.

    All major research results presented in the thesis have beenverified experimentally.

    KeywordsTeleoperator, Force Feedback, Passivity, StiffContacts, Control, Robustness, Transparency, Bone Milling,Uncertainty

  • 49.
    Flemmer, Henrik
    et al.
    KTH, Superseded Departments, Machine Design.
    Eriksson, Bengt
    KTH, Superseded Departments, Machine Design.
    Wikander, Jan
    KTH, Superseded Departments, Machine Design.
    Control Design for Transparent Teleoperators with Model Parameter Variation2002Conference paper (Refereed)
  • 50.
    Flemmer, Henrik
    et al.
    KTH, Superseded Departments, Machine Design.
    Eriksson, Bengt
    KTH, Superseded Departments, Machine Design.
    Wikander, Jan
    KTH, Superseded Departments, Machine Design.
    Passivity Issues in Bilateral Teleoperation: A Phase Property2003Conference paper (Refereed)
12345 1 - 50 of 247
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