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  • 101.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Ishiguro, Hiroshi
    Osaka University.
    Asada, Minoru
    JST Erato Asada Synergistic ntelligence Project and Osaka University.
    Shapiro, Stuart C.
    State University of New York at Buffalo.
    Thielscher, Michael
    Dresden University of Technology.
    Breazeal, Cynthia
    MIT Media Lab.
    Mataric, Maja J.
    University of Southern California.
    Ishida, Hiroshi
    Tokyo University of Agriculture and Technology.
    Human-inspired robots2006In: IEEE Intelligent Systems, ISSN 1541-1672, Vol. 21, no 4, p. 74-85Article in journal (Refereed)
    Abstract [en]

    Future robots will work in hospitals, elderly care centers, schools, and homes. Similarity with humans can facilitate interaction with a variety of users who don't have robotics expertise, so it make sense to take inspiration from humans when developing robots. However, humanlike appearance can also be deceiving, convincing users that robots can understand and do much more than they actually can. Developing a humanlike appearance must go hand in hand with increasing robots' cognitive, social, and perceptive capabilities. This installment of Trends & Controversies explores different aspects of human-inspired robots.

  • 102.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    An introduction to the anchoring problem2003In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 43, no 2-3, p. 85-96Article in journal (Refereed)
    Abstract [en]

    Anchoring is the problem of connecting, inside an artificial system, symbols and sensor data that refer to the same physical objects in the external world. This problem needs to be solved in any robotic system that incorporates a symbolic component. However, it is only recently that the anchoring problem has started to be addressed as a problem per se, and a few general solutions have begun to appear in the literature. This paper introduces the special issue on perceptual anchoring of the Robotics and Autonomous Systems journal. Our goal is to provide a general overview of the anchoring problem, and to highlight some of its subtle points

  • 103.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Anchoring symbols to sensor data: preliminary report2000In: Proceedings of the 17th AAAI conference, 2000, p. 129-135Conference paper (Refereed)
    Abstract [en]

    Anchoring is the process of creating and maintaining the correspondence between symbols and percepts that refer to the same physical objects. Although this process must necessarily be present in any physically embedded system that includes a symbolic component (e.g., an autonomous robot), no systematic study of anchoring as a problem per se has been reported in the literature on intelligent systems. In this paper, we propose a domain-independent definition of the anchoring problem, and identify its three basic functionalities: find, reacquire, and track. We illustrate our definition on two systems operating in two different domains: an unmanned airborne vehicle for traffic surveillance; and a mobile robot for office navigation.

  • 104.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Anchoring symbols to vision data by fuzzy logic1999In: Symbolic and quantitative approaches to reasoning and uncertainty: European conference, ECSQARU '99 : proceedings / [ed] Anthony Hunter, Simon Parsons, Berlin/Heidelberg: Springer Berlin/Heidelberg, 1999, p. 104-115Conference paper (Refereed)
    Abstract [en]

    Intelligent agents embedded in physical environments need the ability to connect, or anchor, the symbols used to perform abstract reasoning to the physical entities which these symbols refer to. Anchoring must rely on perceptual data which is inherently affected by uncertainty. We propose an anchoring technique based on the use of fuzzy sets to represent uncertainty, and of degree of subset-hood to compute the partial match between signatures of objects. We show examples where we use this technique to allow a deliberative system to reason about the objects (cars) observed by a vision system embarked in an unmanned helicopter, in the framework of the WITAS project.

  • 105.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Perceptual anchoring: a key concept for plan execution in embedded systems2002In: Advances in Plan-Based Control of Robotic Agents / [ed] Michael Beetz, Joachim Hertzberg, Malik Ghallab, Martha E. Pollack, 2002, Vol. 2466, p. 97-126Conference paper (Refereed)
    Abstract [en]

    Anchoring is the process of creating and maintaining the correspondence between symbols and percepts that refer to the same physical objects. This process must necessarily be present in any physically embedded system that includes a symbolic component, for instance, in an autonomous robot that uses a planner to generate strategic decisions. However, no systematic study of anchoring as a problem per se has been reported in the literature on intelligent systems. In this paper, we advocate for the need for a domain-independent framework to deal with the anchoring problem, and we report some initial steps in this direction. We illustrate our arguments and framework by showing experiments performed on a real mobile robot

  • 106.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Perceptual anchoring of symbols for action2001In: Proceedings of the 17th IJCAI, 2001, p. 407-412Conference paper (Refereed)
    Abstract [en]

    Anchoring is the process of creating and maintaining the correspondence between symbols and percepts that refer to the same physical objects. Although this process must necessarily be present in any symbolic reasoning system embedded in a physical environment (e.g., an autonomous robot), the systematic study of anchoring as a clearly separated problem is just in its initial phase. In this paper we focus on the use of symbols in actions and plans and the consequences this has for anchoring. In particular we introduce action properties and partial matching of objects descriptions. We also consider the use of indefinite references in the context of action. The use of our formalism is exemplified in a mobile robotic domain

  • 107.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Perceptual anchoring with indefinite descriptions2003Conference paper (Refereed)
    Abstract [en]

    Anchoring is the problem of how to connect, inside an artificial system, the symbol-level and signal-level representations of the same physical object. In most previous work on anchoring, symbol-level representations were meant to denote one specific object, like 'the red pen p22'. These are also called definite descriptions. In this paper, we study anchoring in the case of indefinite descriptions, like `a red pen x'. A key point of our study is that anchoring with an indefinite description involves, in general, the selection of one object among several perceived objects that satisfy that description. We analyze several strategies to perform object selection, and compare them with the problem of action selection in autonomous embedded agents.

  • 108.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Symbiotic Robotic Systems: Humans, Robots, and Smart Environments2006In: IEEE Intelligent Systems, ISSN 1541-1672, Vol. 21, no 3, p. 82-84Article in journal (Refereed)
    Abstract [en]

    A symbiotic robotic system consists of a robot, a human, and a (smart) environment that cooperate symbiotically to perform a task. While the possibility of cooperating with the smart environment and with humans might greatly simplify the execution of robotic tasks, it also presents new challenges that open new research directions. In this article, we claim that symbiotic robotic systems will constitute a dominant new paradigm in the future of autonomous robotics, and discuss the corresponding potential and scientific challenges. This article is part of a special issue on the Future of AI.

  • 109.
    Duckett, Tom
    et al.
    Örebro University, Department of Technology.
    Axelsson, Mikael
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Learning to locate an odour source with a mobile robot2001In: IEEE international conference on robotics and automation: ICRA 2001, 2001, p. 4017-4022Conference paper (Refereed)
    Abstract [en]

    We address the problem of enabling a mobile robot to locate a stationary odour source using an electronic nose constructed from gas sensors. On the hardware side, we use a stereo nose architecture consisting of two parallel chambers, each containing an identical set of sensors. On the software side, we use a recurrent artificial neural network to learn the direction to a stationary source from a time series of sensor readings. This contrasts with previous approaches, that rely on the existence of a model of the sensor's dynamics. The complete system is able to orient and turn towards the source. An experimental validation was carried out to evaluate the performance of the system.

  • 110.
    Duckett, Tom
    et al.
    Örebro University, Department of Technology.
    Marsland, Stephen
    University of Manchester.
    Shapiro, Jonathan
    University of Manchester.
    Fast, on-line learning of globally consistent maps2002In: Autonomous Robots, ISSN 0929-5593, E-ISSN 1573-7527, Vol. 12, no 3, p. 287-300Article in journal (Refereed)
    Abstract [en]

    To navigate in unknown environments, mobile robots require the ability to build their own maps. A major problem for robot map building is that odometry-based dead reckoning cannot be used to assign accurate global position information to a map because of cumulative drift errors. This paper introduces a fast, on-line algorithm for learning geometrically consistent maps using only local metric information. The algorithm works by using a relaxation technique to minimise an energy function over many small steps. The approach differs from previous work in that it is computationally cheap, easy to implement and is proven to converge to a globally optimal solution. Experiments are presented in which large, complex environments were successfully mapped by a real robot.

  • 111.
    Duckett, Tom
    et al.
    Örebro University, Department of Technology.
    Nehmzow, Ulrich
    University of Manchester.
    Mobile robot self-localisation using occupancy histograms and a mixture of Gaussian location hypotheses2001In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 34, no 2-3, p. 117-129Article in journal (Refereed)
    Abstract [en]

    The topic of mobile robot self-localisation is often divided into the sub-problems of global localisation and position tracking. Both are now well understood individually, but few mobile robots can deal simultaneously with the two problems in large, complex environments. In this paper, we present a unified approach to global localisation and position tracking which is based on a topological map augmented with metric information. This method combines a new scan matching technique, using histograms extracted from local occupancy grids, with an efficient algorithm for tracking multiple location hypotheses over time. The method was validated with experiments in a series of real world environments, including its integration into a complete navigating robot. The results show that the robot can localise itself reliably in large, indoor environments using minimal computational resources

  • 112.
    Duckett, Tom
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Building globally consistent gridmaps from topologies2000In: Proceedings of the 6th international symposium on robot control: IFAC - (SYROCO), 2000, p. 357-361Conference paper (Refereed)
    Abstract [en]

    This paper addresses the problem of recovering metric consistency in a global gridmap for mobile robot navigation. Gridmaps can only be updated consistently using exact estimates of the robot position, a requirement which is very hard to fulfil in real world environments because the same sensor data must be used for both map building and self-localisation. To overcome this problem, we use a hierarchy of robot maps which integrates topological and grid-based representations. The consistency problem is solved at the topological level, by applying a relaxation technique to generate coordinates for the places in the robot's map. Consequently, the robot is able to recover a globally consistent gridmap without requiring accurate sensors or high computational costs. Experiments on a Nomad 200 robot are presented which demonstrate the efficacy of our approach.

  • 113.
    Enghag, Per
    et al.
    Örebro University, Department of Technology.
    Larsson, Rune
    Örebro University, Department of Technology.
    Pettersson, Kjell
    Örebro University, Department of Technology.
    An investigation into the forces and friction in wire drawing2001In: Wire Industry, ISSN 0043-6011, Vol. 68, no 809, p. 272-277Article in journal (Refereed)
    Abstract [en]

    The drawing machine equipped with load cells, is demostrated to measure drawing forces and calculate friction coefficients. The measurement is reported using the drawing of one wire with one lubricant but with different reductions and die geometries. The planned utilisation of the drawing machine is helpful in the investigation of unknown parameters in the wire drawing process. The machine is used for the study of surface condition of mechanically scaled wires, lubricants and carriers of different wire types and the pressure and rotating dies.

  • 114. Eriksson, Conny
    et al.
    Lundberg, Sven-Erik
    Örebro University, Department of Technology.
    Working range of roll pass sequences in wire rod rolling with interstand tensions2004In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 31, no 1, p. 81-92Article in journal (Refereed)
    Abstract [en]

    In the high speed rolling of wire rod in blocks, interstand tensions are utilised in order to keep the process stable. However, interstand tensions influence the rolling process, and especially the spread and forward slip, which are dependent of tensions between the stands. By the influence on spread, the tolerances of the rolled product depend on the tensions and usually the interstand tensions are kept as low as possible in order to obtain required tolerances. A narrow spread technology is used to utilise interstand tensions in order to increase the working range of a pass sequence and move the product range towards smaller sizes. By adapting a certain amount of interstand tensions, smaller sizes can be rolled by a given roll pass schedule. A practical problem in this method is the fixed gearings in the common blocks, which require a certain and given level of interstand tensions and corresponding reductions. In the latest generation of blocks, where the stands are arranged in units, two by two, with each unit driven by a dedicated electrical motor, it is possible to introduce 'inter unit' tensions, and by this method extend the working range of the pass sequence. A special computer program for analysis of interstand tensions has been developed by combining a program TENSION, developed at the Royal Institute of Technology in Stockholm, dealing with the basic principles of rolling with interstand tensions, with the recently published program WORKRAN, which analyses the working range of any roll pass sequence built up by common two-symmetrical grooves. From the analysis and experimental data it is shown that interstand tensions at the level of 10% of the yield stress of the material increase the working range in a six stand block by 2% and reduce the lower limit of the exit section area by about 15%. Higher tension levels have a larger effect both on the extension of the working range and on the reduction of the minimum exit area but it becomes more difficult to control the tolerances at higher tension levels. The influence of interstand tensions on the reduction and on the working range of the pass sequence is mainly obtained by the influence on the round passes, while the oval passes have a counteracting effect on the influence of interstand tensions

  • 115.
    Fabrizi, Elisabetta
    et al.
    Università di Roma “La Sapienza”.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Augmenting topology-based maps with geometric information2000In: Proceedings of the 6th international conference on intelligent autonomous systems: IAS, 2000, p. 604-661Conference paper (Refereed)
    Abstract [en]

    Topology-based maps are a new representation of the workspace of a mobile robot based on the topological notions of connectivity and adjacency. In this paper, we show how to enrich a topology-based map with geometric information useful for planning and navigation. Both the topology-based map and this geometric information are automatically extracted from sensor data.

  • 116.
    Fabrizi, Elisabetta
    et al.
    La Sapienza - Roma.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Augmenting topology-based maps with geometric information2002In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 40, no 2, p. 91-97Article in journal (Refereed)
    Abstract [en]

    Topology-based maps are a new representation of the workspace of a mobile robot, which capture the structure of the free space in the environment in terms of the basic topological notions of connectivity and adjacency. A topology-based map can represent the environment in terms of open spaces (rooms and corridors) connected by narrow passages (doors and junctions). In this paper, we show how to enrich a topology-based map with geometric information useful for the generation and execution of navigation plans. Both the topology-based map and its geometric information are automatically extracted from sensor data. We illustrate the use of topology-based maps for planned behavior-based navigation on a real robot.

  • 117. Fabrizi, Elisabetta
    et al.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Behavioral navigation on topology-based maps2000In: Proceedings of the 8th international symposium on robotics with applications, 2000Conference paper (Refereed)
    Abstract [en]

    In order to plan behavior-based navigation strategies, a mobile robot needs information about the connectivity of the space, and about those geometric properties that allow the selection of the adequate behavior in each area. We propose to represent this information by a topology-based map, a graph that encodes the topological structure of the free space in the environment, in which nodes represent large open spaces and arcs represent passages between them. In this paper, we show how to extract a topology-based map from a fuzzy occupancy grid using image processing techniques, and how to use this map for planning behavioral navigation. We illustrate our technique by giving an example of office navigation on a real robot

  • 118. Fabrizi, Elisabetta
    et al.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Extracting topology-based maps from gridmaps2000In: IEEE international conference on robotics and automation, ICRA '00: proceedings, 2000, p. 2972-2978Conference paper (Refereed)
    Abstract [en]

    We propose topology-based maps as a new representation of the workspace of a mobile robot. These maps capture the structure of the free space in the environment in terms of the basic topological notions of connectivity and adjacency. Topology-based maps can be automatically extracted from an occupancy grid built from sensor data using techniques borrowed from the image processing field. Since these techniques can be soundly defined on fuzzy values, our approach is well suited to deal with the uncertainty inherent in the sensor data. Topology-based maps are fairly robust with respect to sensor noise and to small environmental changes, and have nice computational properties.

  • 119. Filipovic, Mirjana
    et al.
    Ericsson, Conny
    Överstam, Henrik
    Örebro University, Department of Technology.
    Behaviour of surface defects in wire rod rolling2006In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 77, no 6, p. 439-444Article in journal (Refereed)
    Abstract [en]

    Defects are often present in rolled products, such as wire rod. The market demand for wire rod without any defects has increased. In the final wire rod products, defects originating from steel making, casting, pre-rolling of billets and during wire rod rolling can appear. In this work, artificial V-shaped longitudinal surface cracks have been analysed experimentally and by means of FEM. The results indicate that the experiments and FEM calculations show the same tendency except in two cases, where instability due to fairly "round" false round bars disturbed the experiment. FE studies in combination with practical experiments are necessary in order to understand the behaviour of the material flows in the groove and to explain whether the crack will open up as a V-shape or if it will be closed as an I-shape.

  • 120.
    Fleck, Sven
    et al.
    University of Tübingen.
    Busch, Florian
    University of Tübingen.
    Biber, Peter
    University of Tübingen.
    Strasser, Wolfgang
    University of Tübingen.
    Andreasson, Henrik
    Örebro University, Department of Technology.
    Omnidirectional 3D modeling on a mobile robot using graph cuts2005In: Proceedings of the 2005 IEEE International Converence on Robotics and Automation: ICRA - 2005, 2005, p. 1748-1754Conference paper (Refereed)
    Abstract [en]

    For a mobile robot it is a natural task to build a 3D model of its environment. Such a model is not only useful for planning robot actions but also to provide a remote human surveillant a realistic visualization of the robot’s state with respect to the environment. Acquiring 3D models of environments is also an important task on its own with many possible applications like creating virtual interactive walkthroughs or as basis for 3D-TV.

    In this paper we present our method to acquire a 3D model using a mobile robot that is equipped with a laser scanner and a panoramic camera. The method is based on calculating dense depth maps for panoramic images using pairs of panoramic images taken from different positions using stereo matching. Traditional 2D-SLAM using laser-scan-matching is used to determine the needed camera poses. To receive high-quality results we use a high-quality stereo matching algorithm – the graph cut method. We describe the necessary modifications to handle panoramic images and specialized post-processing methods.

  • 121.
    Frese, Udo
    et al.
    University of Bremen.
    Larsson, Per
    NamaTec AB.
    Duckett, Tom
    Örebro University, Department of Technology.
    A multilevel relaxation algorithm for simultaneous localisation and mapping2005In: IEEE Transactions on robotics, ISSN 1552-3098, E-ISSN 1941-0468, Vol. 21, no 2, p. 196-207Article in journal (Refereed)
    Abstract [en]

    This paper addresses the problem of simultaneous localisation and mapping (SLAM) by a mobile robot. An incremental SLAM algorithm is introduced that is derived from multigrid methods used for solving partial differential equations. The approach improves on the performance of previous relaxation methods for robot mapping because it optimizes the map at multiple levels of resolution. The resulting algorithm has an update time that is linear in the number of estimated features for typical indoor environments, even when closing very large loops, and offers advantages in handling non-linearities compared to other SLAM algorithms. Experimental comparisons with alternative algorithms using two well-known data sets and mapping results on a real robot are also presented

  • 122.
    Frisk, Margot
    et al.
    Örebro University, Department of Health Sciences.
    Arvidsson, Helena
    Arbets- och miljömed. kliniken, USÖ.
    Kiviloog, Jaak
    Lungkliniken, USÖ.
    Ivarsson, Ann-Britt
    Örebro University, Department of Health Sciences.
    Kamwendo, Kitty
    Örebro University, Department of Health Sciences.
    Stridh, Göran
    Örebro University, Department of Technology.
    An investigation of the housing environment for persons with asthma and persons without asthma2006In: Scandinavian Journal of Occupational Therapy, ISSN 1103-8128, E-ISSN 1651-2014, Vol. 13, no 1, p. 4-12Article in journal (Refereed)
    Abstract [en]

    Asthma is a chronic disease affected by environmental factors that may increase symptoms that impact on a persons' well-being. An important issue in occupational therapy is to improve the relationship between a person's functional capacity and the physical environment. The aim of the study was to compare the housing environment of persons with asthma (cases, n=49) and persons without asthma (controls, n=48), with regard to building construction and condition, physical, chemical and biological factors, and cleaning routines. A secondary aim was to compare different types of accommodation within cases and controls. A specialist team, including a construction engineer, a biological scientist, and an occupational therapist, conducted the study. Data were collected using protocols, as well as a number of established technical methods from the field of occupational and environmentsl medicine. The primary results showed no major differences in the housing environment between the two groups. However, in individual homes environmental factors at levels that could increase symptoms were identified. When single-familyhouses were compared with multi-family houses, significant differences were found indicating that preventive interventions may be needed in some single-family houses. Further studies are needed to clarify the person-environment relationship for persons with asthma, focusing on their ability to perform daily activities.

  • 123. Galindo, Cipriano
    et al.
    Fernandez-Madrigal, Juan-Antonio
    Gonzalez, Javier
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Buschka, Par
    Life-long optimization of the symbolic model of indoor environments for a mobile robot2007In: IEEE transactions on systems, man and cybernetics. Part B. Cybernetics, ISSN 1083-4419, E-ISSN 1941-0492, Vol. 37, no 5, p. 1290-1304Article in journal (Refereed)
    Abstract [en]

    The use of a symbolic model of the spatial environment becomes crucial for a mobile robot. that is intended to operate optimally and intelligently in indoor scenarios. Constructing such a model involves important problems that are not solved completely at present. One is called anchoring, which implies to maintain a correct dynamic correspondence between the real world and the symbols in the model. The other problem is adaptation: among the numerous possible models that could be constructed for representing a given environment, optimization involves the selection of one that improves as much as possible the operations of the robot. To cope with both problems, in this paper, we propose a framework that allows an indoor mobile robot to learn automatically a symbolic model of its environment and to optimize it over time with respect to changes in both the environment and the robot operational needs through an evolutionary algorithm. For coping efficiently with the large amounts of information that the real world provides, we use abstraction, which also helps in improving task planning. Our experiments demonstrate that the proposed framework is suitable for providing an indoor mobile robot with a good symbolic model and adaptation capabilities.

  • 124. Galindo, Cipriano
    et al.
    Fernández-Madrigal, Juan Antonio
    González, Javier
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Using semantic information for improving efficiency of robot task planning2007Conference paper (Refereed)
    Abstract [en]

    The use of semantic information in robotics is an emergent field of research. As a supplement to other types of information, like geometrical or topological, semantics can improve mobile robot reasoning or knowledge inference, and can also facilitate human-robot communication. These abilities are particularly relevant for robots intended to operate in everyday environments populated by people, which typically involve a great number of objects, places, and possible actions. In this paper, we explore a novel usage of semantic information: as an improvement for task planning in complex scenarios like the mentioned ones, where other planners easily find intractable situations. More specifically, we propose to first construct a "semantic" plan composed of categories of objects, places, etc. that solves a "generalized" version of the requested task, and then to use that plan for discarding irrelevant information in the definitive planning carried out on the symbolic instances of those elements (that correspond to physical elements of the world with which the robot can operate). Our results using this approach are promising, and have been compared to other existing approaches.

  • 125. Galindo, Cipriano
    et al.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Coradeschi, Silvia
    Örebro University, Department of Technology.
    Buschka, Pär
    Örebro University, Department of Technology.
    Fernández-Madrigal, J. A.
    González, J.
    Multi-hierarchical semantic maps for mobile robotics2005In: 2005 IEEE/RSJ international conference on intelligent robots and systems (IROS 2005), 2005, p. 2278-2283Conference paper (Other academic)
    Abstract [en]

    The success of mobile robots, and particularly of those interfacing with humans in daily environments (e.g., assistant robots), relies on the ability to manipulate information beyond simple spatial relations. We are interested in semantic information, which gives meaning to spatial information like images or geometric maps. We present a multi-hierarchical approach to enable a mobile robot to acquire semantic information from its sensors, and to use it for navigation tasks. In our approach, the link between spatial and semantic information is established via anchoring. We show experiments on a real mobile robot that demonstrate its ability to use and infer new semantic information from its environment, improving its operation.

  • 126. Garipov, Emil
    et al.
    Stoilkov, Teodor
    Kalaykov, Ivan
    Örebro University, Department of Technology.
    Multiple-model dead-beat controller in case of control signal constraints2007In: ICINCO 2007: proceedings of the Fourth International Conference on Informatics in Control, Automation and Robotics, Signal Processing, Systems Modeling and Control / [ed] Janan Zaytoon, Jean-Louis Ferrier, Juan Andrade-Cetto, Joaquim Filipe, INSTICC Press , 2007, p. 171-177Conference paper (Refereed)
    Abstract [en]

    The task of achieving a dead-beat control by a linear DB controller under control constraints is presented in this paper. Two algorithms using the concept of multiple-model systems are proposed and demonstrated - a multiple-model dead-beat (MMDB) controller with varying order using one sampling period and a MMDB controller with fixed order using several sampling periods. The advantages and disadvantages of these controllers are summarized.

  • 127. Gasós, Jorge
    et al.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Integrating fuzzy geometric maps and topological maps for robot navigation1999Conference paper (Refereed)
    Abstract [en]

    Autonomous mobile robots need to use spatial information about the environment in order to effectively plan and execute navigation tasks. This information can be represented at different level of abstractions, ranging from detailed geometric maps to coarse topological maps. Each level is adequate for some sub-tasks, but not for others. In this paper, we propose to use hybrid maps, patchworks of local metric maps connected into a topological network. Our hybrid maps are peculiar in that they use fuzzy sets to represent the uncertainty that affects metric information. We show how a robot can build hybrid maps from sensor data, and how it can use them in autonomous indoor navigation. We also report experiments performed on a real mobile robot that demonstrate the robustness of our approach with respect to inaccuracies in the map and noise in the sensor data.

  • 128.
    Gasós, Jorge
    et al.
    Université Libre de Bruxelles.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Using fuzzy sets to represent uncertain spatial knowledge in autonomous robots1999In: Spatial Cognition and Computation, ISSN 1387-5868, E-ISSN 1573-9252, Vol. 1, no 3, p. 205-226Article in journal (Refereed)
    Abstract [en]

    Autonomous mobile robots need the capability to reason from and about spatial knowledge. Due to limitations in the prior information and in the perceptual apparatus, this knowledge is inevitably affected by uncertainty. In this paper, we discuss some techniques employed in the field of autonomous robotics to represent and use uncertain spatial knowledge. We focus on techniques which use fuzzy sets to account for the different facets of uncertainty involved in spatial knowledge. These facets include the false measurements induced by bad observation conditions; the inherent noise in odometric position estimation; and the vagueness introduced by the use of linguistic descriptions. To make the discussion more concrete, we illustrate some of these techniques showing samples from our work on mobile robots.

  • 129.
    Gillström, Peter
    Örebro University, Department of Technology.
    Alternativ till betning vid tråddragning: skalbrytning och borstning som metod vid glödskalsrensning på valstråd av kolstål2004In: Stål 2004, 2004, p. 67-68Conference paper (Other academic)
  • 130.
    Gillström, Peter
    Örebro University, Department of Technology.
    Alternatives to pickling: preparation of carbon and low alloyed steel wire rod2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A well established method for scale removal on hot rolled wire rod is pickling. To avoid pollution problems, the wire rod can be mechanically descaled. By this method, the removed scale can be recirculated to the blast furnace.

    In batch pickling considerable energy is necessary; e.g. for heating of the pickling baths, ventilation of acid fumes and application of lubricant carrier. Energy consumption of the alternative descaling methods has been assessed and compared to pickling

    A method was developed to evaluate the remaining scale on mechanically descaled wire rod. Stretching experiments were used to evaluate adhesion of scale to the wire rod surface of different steel grades. Most of the scale was removed on the carbon steel grades and Cr/V alloyed steel grades. More scale remained on silicon alloyed steel grades.

    Shot blasting with steel shots was studied as an alternative to pickling. This method removed the scale on all studied steel grades, even the silicon alloyed grades. The wire rod surface was much rougher compared to the pickled wire rod surface. The shot blast power consumption was measured and evaluated. The PC strand wire gave more wear of dies otherwise the shot blasted wire rod showed no difference in the wire drawing process compared to pickled wire rod. Downstream problems such as cleaning and adherence of copper were observed.

    Reverse bending and brushing with steel brushes and brushes with SiC abrasives were studied on wire rod of low carbon and silicon chromium alloyed steel grades. Scale remained in surface valleys after brushing of the low carbon steel grade. The silicon steel grades were not possible to descale by bending and brushing. Surface defects from brushing were observed on wire rods brushed by steel brushes, but not on wire rod brushed by SiC-nylon brushes.

    A study of shot blasting with recycled glass was done. Due to the lower density, the shot velocity must be higher than for steel shots. Recycled glass gives an irregular surface of the wire, including chip formation, which can improve the lubricant carrying ability of the wire rod surface, but also increase the risk for reduction of the fatigue strength of the wire.

    The differences of die wear using wire rods descaled by two treatments; pickling and reversed bending has been studied. The study gave a background of wear mechanism and described a method to estimate die wear in wire drawing. The conclusions of the experiments indicate that the method for wire rod preparation seems to be of minor importance for the wear of die. The wear rate of a die used in the sixth draft was one order of magnitude lower than the wear rate of the die in the first draft. Abrasive wear is present presumably from the WC grains, torn out in the adhesive wear, on both dies used on pickled wire rod and reverse bent and steel wool cleaned wire rod.

    In order to evaluate new methods to descale wire rod, the effect of thermal shock has been studied. An estimation of the stresses, developed in the oxide during cooling after hot rolling and a FEM-simulation during cooling from ambient temperature down to 77 K, has been made. Experiments using liquid nitrogen, flame and steam to descale wire rod have been performed with mild steel and silicon and chromium steel wire rod. The experiments have shown that thermal shock cannot descale the wire rod. Only a descaling effect from the flame has been found.

    List of papers
    1. Determination of scale amount on wire of carbon steels and low alloyed steels
    Open this publication in new window or tab >>Determination of scale amount on wire of carbon steels and low alloyed steels
    2003 (English)In: Wire Journal International, ISSN 0277-4275, Vol. 36, no 9, p. 73-77Article in journal (Refereed) Published
    Abstract [en]

    Scale amount on wire of carbon steels and low alloyed steels was discussed. Metal microscopy and scanning electron microscopy were used. It was found that this method can determine the scale determinations after the material has been stretched.

    Research subject
    Mechanical Engineering
    Identifiers
    urn:nbn:se:oru:diva-3063 (URN)
    Available from: 2006-03-17 Created: 2006-03-17 Last updated: 2017-10-18Bibliographically approved
    2. Replacement of pickling with shot blasting for wire rod preparation
    Open this publication in new window or tab >>Replacement of pickling with shot blasting for wire rod preparation
    2004 (English)In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 33, no 5, p. 269-278Article in journal (Refereed) Published
    Abstract [en]

    An oxide scale layer covers steel wire rod produced by hot rolling. This oxide is often removed by pickling before wire drawing; otherwise, hard oxides will be impressed into the wire surface and give an inferior surface quality. Stricter pollution regulations increase the incentive to replace pickling with mechanical descaling. This paper gives results from tests on carbon steels by using shot blasting to descale wire rod. The tests include: (i) shot blasting experiments in an industrial full-scale in-line shot blasting machine, (ii) laboratory drawing experiments on shot blasted wire rod, (iii) industrial trials on shot blasted wire rod at the drawing plants. There are differences in the appearance of surfaces between shot blasted and pickled wires, but no differences in the drawing process were observed in the laboratory experiment. In the industrial trials the wear of dies were more severe when drawing shot blasted wire of one of the steel grades. In the downstream processes, problems were recorded with the cleanness of the surface of another grade and adhesion of copper coating on a third grade.

    Research subject
    Mechanical Engineering
    Identifiers
    urn:nbn:se:oru:diva-3064 (URN)10.1111/j.1600-0692.2004.00692.x (DOI)000224243300003 ()2-s2.0-7544234544 (Scopus ID)
    Available from: 2006-03-17 Created: 2006-03-17 Last updated: 2023-12-08Bibliographically approved
    3. Mechanical descaling of wire rod using reverse bending and brushing
    Open this publication in new window or tab >>Mechanical descaling of wire rod using reverse bending and brushing
    2006 (English)In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 172, no 3, p. 332-340Article in journal (Refereed) Published
    Abstract [en]

    Wire rods are covered with an oxide layer, which must be removed before wire drawing. This paper presents an investigation of mechanical descaling by reverse bending and brushing as replacement for pickling. Steel grades studied were low carbon steel and silicon chromium steel. Brushing was done with steel brushes and nylon brushes with SiC. The amount of scale remaining after reverse bending of the low carbon steel depended on the roller diameter. After brushing traces of scale remained in valleys on the surface. Surface damage was observed after brushing with steel brushes but not after SiC-nylon brushing. Silicon chromium alloyed steel was not possible to clean by bending and brushing with the roller diameters studied. The electrical energy required for the mechanical descaling of low C steel may be estimated to be 7kWh/tonne with SiC-nylon brushes and 14kWh/tonne with steel brushes. [All rights reserved Elsevier]

    Place, publisher, year, edition, pages
    Amsterdam: Elsevier, 2006
    Keywords
    bending, carbon steel, drawing (mechanical), pickling (materials processing), rods (structures), rollers (machinery), wires
    National Category
    Engineering and Technology
    Research subject
    Mechanical Engineering
    Identifiers
    urn:nbn:se:oru:diva-4438 (URN)10.1016/j.jmatprotec.2005.10.014 (DOI)000236294600003 ()2-s2.0-33344472880 (Scopus ID)
    Available from: 2007-07-12 Created: 2007-07-12 Last updated: 2023-12-08Bibliographically approved
    4. Shot blasting of billets and wire rod
    Open this publication in new window or tab >>Shot blasting of billets and wire rod
    2005 (English)In: Metallurgy and new materials researches, ISSN 1221-5503, Vol. 13, no 4, p. 1-21Article in journal (Refereed) Published
    Abstract [en]

    A model for work and power in shot blasting is derived. A study is made to use recycled glass as a shot blasting media. The theoretical model must be adjusted for strain hardening material. The experiments indicate that the average shear yield stress is more than twice the initial value for austenitic stainless steels. Soft materials get rough surfaces in shot blasting, which can be advantageous for the ability to carry the wire drawing lubricant. Recycled glass is a possible shot material. Due to the lower density, the shot velocity must be higher than for steel shots. This effect becomes larger by rotation of the glass shots during operation. Recycled glass gives irregular surface, including chip formation, which can improve the lubricant carrying ability of the wire rod surface, but also increase the risk for reduction of the fatigue strength of the wire.

    Research subject
    Mechanical Engineering
    Identifiers
    urn:nbn:se:oru:diva-3066 (URN)
    Note
    Tidskriftens parallelltitel: Cercetari Metalurgice si de noi MaterialeAvailable from: 2006-03-17 Created: 2006-03-17 Last updated: 2017-10-18Bibliographically approved
    5. Wear of die after drawing of pickled or reverse bent wire rod
    Open this publication in new window or tab >>Wear of die after drawing of pickled or reverse bent wire rod
    2007 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 262, no 7-8, p. 858-867Article in journal (Refereed) Published
    Abstract [en]

    The object of this paper was to evaluate the difference of die wear by using wire rods descaled by two different treatments; pickling or reversed bending. The paper gives a background of wear mechanism and describe a method to estimate die wear in wire drawing. The conclusions of the experiments were that the wire rod preparation seems to be of minor importance for the wear of die. A die in the sixth draft had a magnitude lower wear, compared to the die in the first draft. Abrasive wear is present from the WC grains, torn out in the adhesive wear, on both dies used on pickled wire rod and reverse bent and steel wool cleaned wire rod. © 2006 Elsevier B.V. All rights reserved.

    Place, publisher, year, edition, pages
    Amsterdam: Elsevier, 2007
    Keywords
    Descaling, Drawing dies, Pickling, Wire drawing, Wire rods, Adhesive wear
    National Category
    Engineering and Technology
    Research subject
    Mechanical Engineering
    Identifiers
    urn:nbn:se:oru:diva-4354 (URN)10.1016/j.wear.2006.08.016 (DOI)000245063500012 ()2-s2.0-33847015253 (Scopus ID)
    Available from: 2007-07-12 Created: 2007-07-12 Last updated: 2023-12-08Bibliographically approved
    6. Descaling of wire rod by using the effect of thermal shock: liquid nitrogen, steam or flame
    Open this publication in new window or tab >>Descaling of wire rod by using the effect of thermal shock: liquid nitrogen, steam or flame
    (English)Manuscript (preprint) (Other academic)
    Research subject
    Mechanical Engineering
    Identifiers
    urn:nbn:se:oru:diva-3068 (URN)
    Available from: 2006-03-17 Created: 2006-03-17 Last updated: 2017-10-18Bibliographically approved
  • 131.
    Gillström, Peter
    Örebro University, Department of Technology.
    An alternative preparation to pickling in wire drawing2003Conference paper (Other academic)
  • 132.
    Gillström, Peter
    Örebro University, Department of Technology.
    Descaling of wire rod by using the effect of thermal shock: liquid nitrogen, steam or flameManuscript (preprint) (Other academic)
  • 133.
    Gillström, Peter
    Örebro University, Department of Technology.
    Reserapport Italien/Schweiz2003Report (Other (popular science, discussion, etc.))
  • 134.
    Gillström, Peter
    Örebro University, Department of Technology.
    Valstrådspreparering: alternativ till betning2002Conference paper (Other academic)
  • 135.
    Gillström, Peter
    Örebro University, Department of Technology.
    Valstrådspreparering, alternativ till betning: sammanfattning2003Report (Other academic)
  • 136.
    Gillström, Peter
    et al.
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Determination of scale amount on wire of carbon steels and low alloyed steels2002Conference paper (Refereed)
  • 137.
    Gillström, Peter
    et al.
    Örebro University, Department of Technology.
    Jarl, Magnus
    Determination of scale amount on wire of carbon steels and low alloyed steels2003In: Wire Journal International, ISSN 0277-4275, Vol. 36, no 9, p. 73-77Article in journal (Refereed)
    Abstract [en]

    Scale amount on wire of carbon steels and low alloyed steels was discussed. Metal microscopy and scanning electron microscopy were used. It was found that this method can determine the scale determinations after the material has been stretched.

  • 138.
    Gillström, Peter
    et al.
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Mechanical descaling of wire rod using reverse bending and brushing2006In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 172, no 3, p. 332-340Article in journal (Refereed)
    Abstract [en]

    Wire rods are covered with an oxide layer, which must be removed before wire drawing. This paper presents an investigation of mechanical descaling by reverse bending and brushing as replacement for pickling. Steel grades studied were low carbon steel and silicon chromium steel. Brushing was done with steel brushes and nylon brushes with SiC. The amount of scale remaining after reverse bending of the low carbon steel depended on the roller diameter. After brushing traces of scale remained in valleys on the surface. Surface damage was observed after brushing with steel brushes but not after SiC-nylon brushing. Silicon chromium alloyed steel was not possible to clean by bending and brushing with the roller diameters studied. The electrical energy required for the mechanical descaling of low C steel may be estimated to be 7kWh/tonne with SiC-nylon brushes and 14kWh/tonne with steel brushes. [All rights reserved Elsevier]

  • 139.
    Gillström, Peter
    et al.
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Replacement of pickling with shot blasting for wire rod preparation2004In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 33, no 5, p. 269-278Article in journal (Refereed)
    Abstract [en]

    An oxide scale layer covers steel wire rod produced by hot rolling. This oxide is often removed by pickling before wire drawing; otherwise, hard oxides will be impressed into the wire surface and give an inferior surface quality. Stricter pollution regulations increase the incentive to replace pickling with mechanical descaling. This paper gives results from tests on carbon steels by using shot blasting to descale wire rod. The tests include: (i) shot blasting experiments in an industrial full-scale in-line shot blasting machine, (ii) laboratory drawing experiments on shot blasted wire rod, (iii) industrial trials on shot blasted wire rod at the drawing plants. There are differences in the appearance of surfaces between shot blasted and pickled wires, but no differences in the drawing process were observed in the laboratory experiment. In the industrial trials the wear of dies were more severe when drawing shot blasted wire of one of the steel grades. In the downstream processes, problems were recorded with the cleanness of the surface of another grade and adhesion of copper coating on a third grade.

  • 140.
    Gillström, Peter
    et al.
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Valstrådspreparering - alternativ till betning vid tråddragning: slutrapport2003Report (Other academic)
  • 141.
    Gillström, Peter
    et al.
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Wear of die after drawing of pickled or reverse bent wire rod2007In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 262, no 7-8, p. 858-867Article in journal (Refereed)
    Abstract [en]

    The object of this paper was to evaluate the difference of die wear by using wire rods descaled by two different treatments; pickling or reversed bending. The paper gives a background of wear mechanism and describe a method to estimate die wear in wire drawing. The conclusions of the experiments were that the wire rod preparation seems to be of minor importance for the wear of die. A die in the sixth draft had a magnitude lower wear, compared to the die in the first draft. Abrasive wear is present from the WC grains, torn out in the adhesive wear, on both dies used on pickled wire rod and reverse bent and steel wool cleaned wire rod. © 2006 Elsevier B.V. All rights reserved.

  • 142.
    Gillström, Peter
    et al.
    Örebro University, Department of Technology.
    Larsson, Tord
    Örebro University, Department of Technology.
    Energibehov vid betning2005In: Bergsmannen med Jernkontorets annaler : nordisk branschtidning för stål-, metall-, berg- och mineralindustrierna, ISSN 0284-0448, no 4Article in journal (Other (popular science, discussion, etc.))
  • 143.
    Gillström, Peter
    et al.
    Örebro University, Department of Technology.
    Lundberg, Sven-Erik
    Örebro University, Department of Technology.
    Shot blasting of billets and wire rod2005In: Metallurgy and new materials researches, ISSN 1221-5503, Vol. 13, no 4, p. 1-21Article in journal (Refereed)
    Abstract [en]

    A model for work and power in shot blasting is derived. A study is made to use recycled glass as a shot blasting media. The theoretical model must be adjusted for strain hardening material. The experiments indicate that the average shear yield stress is more than twice the initial value for austenitic stainless steels. Soft materials get rough surfaces in shot blasting, which can be advantageous for the ability to carry the wire drawing lubricant. Recycled glass is a possible shot material. Due to the lower density, the shot velocity must be higher than for steel shots. This effect becomes larger by rotation of the glass shots during operation. Recycled glass gives irregular surface, including chip formation, which can improve the lubricant carrying ability of the wire rod surface, but also increase the risk for reduction of the fatigue strength of the wire.

  • 144.
    Gritti, Marco
    et al.
    Örebro University, Department of Technology.
    Broxvall, Mathias
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Reactive self-configuration of an ecology of robots2007Conference paper (Refereed)
    Abstract [en]

    The field of ubiquitous robotics is burgeoning, and different brands of massively distributed heterogeneous robotic systems are being proposed and applied to several domains. The strong added value of these systems comes from their potential ability to dynamically self-configure, by changing the form of their cooperation to adapt to a given task or situation. In face of this, no satisfactory solution exists to the problem of how such a system should self-configure. In this paper, we explore a reactive approach to self-configuration inspired by ideas from the field of semantic web services. We illustrate our approach on a specific type of ubiquitous robot system, called PEIS-Ecology. We show experiments in which our approach autonomously generates a configuration to perform a cooperative navigation task, and dynamically changes this configuration when one of the components fails.

  • 145. Grothérus, Dag
    et al.
    Larsson, Tord
    Örebro University, Department of Technology.
    Ventilation i medelstora och större pannhus2005Report (Other academic)
    Abstract [sv]

    Utformning av pannhus kan sammanfattas enligt nedan:

    - Luftflöde som tillförs pannhuset skall klara av att tillföra erforderlig förbränningsluft samt att kyla pannhuset.

    - Pannhusetventilationen skall utföras som mekanisk ventilation och luften bör tillföras på flera olika nivåer.

    Arbetsmiljögsstiftningen anger cirka 45 oC som högsta lokaltemperatur. Undertrycket i pannhusets nedre del bör inte vara med än 40 Pa för att personalen på ett enkelt sätt skall kunna öppna dörrar vid utrymning.

  • 146. Guarino, Donatella
    et al.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Monitoring the state of a ubiquitous robotic system: a fuzzy logic approach2007In: IEEE international fuzzy systems conference, FUZZ-IEEE 2007, New York: IEEE , 2007, p. 1-6Conference paper (Refereed)
    Abstract [en]

    A trend is emerging in the fields of ambient intelligence (AmI) and autonomous robotics, which points in the direction of a merger between these two fields. The inclusion of robotic devices in AmI system, sometimes named ubiquitous robotics, makes one of the hard problems in this field even harder: how can we provide a comfortable, natural interface between the everyday user and a complex system which consists of a large multitude of highly heterogeneous devices? In this paper, we address a specific, important aspect of this problem: to monitor the state of the ubiquitous system by the user of the system. The solution that we propose is based on two mechanisms: an expression-based semantics to represent in a uniform way the status of heterogeneous devices; and a common interface point to aggregate the information from all devices into a summary status presented to the user. For both mechanisms, we propose to use the tools of fuzzy logic. We justify this choice by arguments grounded in the semantics and formal properties of fuzzy logic. We also illustrate our approach on a specific type of ubiquitous robotic system called Ecology of Physically Embedded Intelligent Systems, or PEIS-Ecology.

  • 147. Guarino, Donatella
    et al.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    On interfacing with an ubiquitous robotic system2006In: 17th European Conference on Artificial Intelligence (ECAI), / [ed] Gerhard Brewka, Silvia Coradeschi, Anna Perini, Paolo Traverso, IOS Press, 2006, p. 857-858Conference paper (Refereed)
    Abstract [en]

    The emerging field of ubiquitous robotics presents new challenges for human-robot interface. In this note, we introduce the concept of a common interface point using an expression-based semantics as a way to address some of these challenges. We illustrate this concept in the framework of the PEIS-Ecology approach to ubiquitous robotics.

  • 148. Hadad, Rabie
    et al.
    Lindgren, Patrik
    Jonsson, Mikael
    Lundberg, Sven-Erik
    Örebro University, Department of Technology.
    A Theoretical / Empirical study of void closure in heavy plate hot rolling of tool steel2009In: Metallurgy and New Materials Researches / Cercetari metalurgice, si de noi materiale, ISSN 1221-5503, Vol. 17, no 1, p. 9-26Article in journal (Other academic)
    Abstract [en]

    By the introduction of TOOLOX®, SSAB in Oxelösund has turned into a new market segment, including heavier sizes and dramatically increased requirements on inner quality of the plate. To be able to determine the minimum reduction from slab to finished plate with acceptable inner quality, a study was made, to evaluate the minimum reduction for a given requirement of inner quality. By experimental rolling in the heavy plate mill in Oxelösund it has been proven that more than 40 % total reduction is necessary for total closure of voids under the geometrical deformation conditions in that mill. The total reduction is more important than the geometrical rolling conditions, and heavy pass reductions are favourable for void closure. The closure of internal defects can be improved by cooling the surface of the slabs.

  • 149. Hansen, Thorbjörn
    et al.
    Jönsson, Pär
    Lundberg, Sven-Erik
    Örebro University, Department of Technology.
    Törresvoll, Ketil
    The concept of the liquid sampling and hot rolling method for determination of macro inclusion characteristics in steel2006In: Steel Research International, ISSN 1611-3683, Vol. 77, no 3, p. 177-185Article in journal (Refereed)
    Abstract [en]

    A novel method for determination of semi-macro and macro size distributions of inclusions in steel from samples in ladle, tundish and mould has been developed. The samples are worked and surface treated before inspection. Mainly immersed ultrasonic scanning is performed to determine the semi-macro and macro inclusion content. The LSHR method has been tested in several different steel plants and for different steel grades. It is concluded that new information regarding large inclusions during steelmaking can be obtained using the method.

  • 150.
    Harrysson, Christer
    Örebro University, Department of Technology.
    Byggbranschens behov av förnyelse: en väg till småhus med lägre livscykelkostnader2006In: Bygg och Teknik, ISSN 0281-658X, E-ISSN 2002-8350, Vol. 98, no 5, p. 61-68Article in journal (Other academic)
    Abstract [sv]

    Småhus byggs på många olika sätt och tekniska lösningar. Några av dessa måste vara bättre än andra. Valet av lösning inriktas ofta på att minska produktionskostnaden utan vederbörlig hänsyn till drift- och underhållskostnader. Produktionskostnaden för småhus har ökat kraftigt liksom energipriset. Olika åtgärders energibesparing har ofta helt eller delvis uteblivit. Byggandet har blivit allt mer komplicerat och påkostat med många nya oprövade material, konstruktioner och installationer. Larmrapporter duggar tätt om hälsoproblem för de boende och byggskador. Nya hus har ofta helt andra och delvis okända egenskaper än tidigare, de är t ex fuktkänsligare.

     

    Råd ges för utformning av energieffektiva och komfortabla småhus till låga livscykelkostnader. Man kan sänka produktionskostnaden med 30 % genom åtgärder som minskar slöseriet under byggprocessen. Den totala energianvändningen för värme, varmvatten och hushållsel kan sänkas med 30 % genom rätt teknisk lösning och god innemiljö utan att öka produktionskostnaden. Fönster ska vara energieffektiva, ytan begränsas till 10 á 15 % av golvarean och avskärmas för besvärande solinstrålning. Luftvärme och energislösande golvvärme bör undvikas.

     

    Energianvändningen i småhus varierar kraftigt mellan såväl nominellt lika som olika hus på grund av skillnader i boendevanor, individuell mätning och debitering av energi och vatten, arbetsutförandets kvalitet (isolering, tätningar, injustering av värme och ventilation) och valet av teknisk lösning.

     

    Småhus byggda sedan mitten på 1980-talet har normalt i medeltal den totala energianvändningen för värme, varmvatten och hushållsel 13 000 – 15 000 kWh/år eller 120 – 130 kWh/m2 år. Det finns en god lösning som har 70 – 80 kWh/m2 år. Denna karakteriseras bland annat av frånluftsventilation med väggventiler och radiatorer samt frånluftsvärmepump för värme och varmvatten. Lösningen ställer inte speciella krav på projektörer, byggare, förvaltare  och brukare till skillnad från passivhus.

     

    Gruppbyggda småhus jämfört med flerbostadshus har i allmänhet per kvadratmeter lägenhetsyta:

    ·        30 % lägre produktionskostnad

    ·        50 % lägre total energianvändning för värme, varmvatten och hushållsel

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