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  • 1.
    Aleotti, Jacopo
    et al.
    Örebro University, Department of Technology.
    Skoglund, Alexander
    Örebro University, Department of Technology.
    Duckett, Tom
    Örebro University, Department of Technology.
    Position teaching of a robot arm by demonstration with a wearable input device2004Conference paper (Refereed)
    Abstract [en]

    This paper describes the first prototype of a "Programming by demonstration" (PbD) system for position teaching of a robot manipulator. A new approach for enabling PbD using supervised learning is presented, by connecting a wearable input device for sensing human arm movements to the software controller of a robot arm. The method does not require analytical modelling of either the human arm or robot, and can be customised for different users and robots. Initial experiments on some simple movements tasks are presented.

  • 2.
    Ananiev, Anani
    et al.
    Örebro University, Department of Technology.
    Michelfelder, Thorsten
    Örebro University, Department of Technology.
    Kalaykov, Ivan
    Örebro University, Department of Technology.
    Driving redundant robots by a dedicated clutch-based actuator2007In: Robot motion and control 2007 / [ed] Krzysztof Kozłowski, Berlin: Springer , 2007, p. 167-176Conference paper (Other academic)
    Abstract [en]

    The redundancy in the body construction of humans and animals makes them very adaptable for a wide variety of natural environments. By switching/activating/deactivating they can accommodate the necessary locomotion for performing almost any task in their lifes. Therefore redundant and hyper-redundant robots are at the focus of research world-wide. The existing hyper-redundant robotic platforms are built in a plenty of mechanical constructions and purposes of use, but have a limited number of useful features that, unfortunately, limit their applicability in some important areas.

  • 3.
    Andersson, Birgitta
    et al.
    Örebro University, Department of Technology.
    Fast, Lars
    Holdstock, Paul
    Pirici, Diana
    Charging of a person exiting a car seat2009Conference paper (Refereed)
    Abstract [en]

    Electrostatic charge is generated by the contact, rubbing together and separation of clothing and car seat upholstery. It is also known that the charging levels will increase in a cold and dry climate. Charge on clothing will induce a separation of charge in the body of the wearer. The net result is an increase in the electrical potential of the body (or body voltage), thereby creating the risk of an electrostatic discharge (ESD) in the form of a spark from the charged human body to a large or earthed conductor. As charge is also bound to the surface of the clothing, brush discharges from the clothing can follow. The effects of sparks from the human body in the environment of a car may be a) to cause uncomfortable and distracting shocks to the person; b) to cause damage or disruption to electronic systems (GPS devices, vehicle management systems, etc); or c) to ignite flammable fuel vapour. A brush discharge from clothing may also ignite fuel vapour and be a risk for (unprotected) sensitive electronic devices (ESDS). The characteristic shape of the discharge current in a brush discharge is very similar to a Human Body Model (HBM) discharge. Measurement systems for determining body voltage and recording brush discharges are described. Results are presented of tests conducted with various combinations of car seat upholstery and clothing in different test environments. The antistatic property of some automotive textiles including conductive threads is emphasized.

  • 4.
    Andersson, Birgitta
    et al.
    Örebro University, Department of Technology.
    Stranneby, Dag
    Örebro University, Department of Technology.
    ESD – elektrostatiska urladdningar: risker och skydd vid elektronikhantering2002Book (Other (popular science, discussion, etc.))
  • 5.
    Andersson, Birgitta
    et al.
    Örebro University, Department of Technology.
    Stranneby, Dag
    Örebro University, Department of Technology.
    Long-term charge retention on PWBs2005In: Journal of Electrostatics, ISSN 0304-3886, E-ISSN 1873-5738, Vol. 63, no 6-10, p. 597-602Article in journal (Refereed)
    Abstract [en]

    A sample of printed wiring boards, isolated from ground, has been charged tribo-electrically and the charge decay process has been studied with focus on the long-term charge decay behaviour. It was found that the time constant 1/e did not say much about the proceeding decay process. Instead a second-order approximation model for the measured decay curves has been suggested.

  • 6. Andersson, K.
    et al.
    Stridh, S.
    Örebro University, Department of Technology.
    Mät bara när mätdata kan förklaras2006In: VVS-forum, ISSN 0346-4644, no 1, p. 20-21Article in journal (Other (popular science, discussion, etc.))
  • 7. Andersson, Kjell
    et al.
    Stridh, Göran
    Örebro University, Department of Technology.
    Bodin, Lennart
    Örebro University, Department of Business, Economics, Statistics and Informatics.
    Besvär av innemiljön: medicinska och psykologiska mekanismer kan förklara2006In: Miljöforskning, ISSN 2000-8627, no 1, p. 20-21Article in journal (Other academic)
  • 8.
    Andersson, Per-Allan
    Örebro University, Department of Technology.
    Läggartemperaturens inverkan på glödskalet, samt dess inverkan på metoden för avlägsning av glödskalet: litteraturstudie2003Report (Other academic)
  • 9.
    Andreasson, Henrik
    Örebro University, Department of Technology.
    Local visual feature based localisation and mapping by mobile robots2008Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis addresses the problems of registration, localisation and simultaneous localisation and mapping (SLAM), relying particularly on local visual features extracted from camera images. These fundamental problems in mobile robot navigation are tightly coupled. Localisation requires a representation of the environment (a map) and registration methods to estimate the pose of the robot relative to the map given the robot’s sensory readings. To create a map, sensor data must be accumulated into a consistent representation and therefore the pose of the robot needs to be estimated, which is again the problem of localisation.

    The major contributions of this thesis are new methods proposed to address the registration, localisation and SLAM problems, considering two different sensor configurations. The first part of the thesis concerns a sensor configuration consisting of an omni-directional camera and odometry, while the second part assumes a standard camera together with a 3D laser range scanner. The main difference is that the former configuration allows for a very inexpensive set-up and (considering the possibility to include visual odometry) the realisation of purely visual navigation approaches. By contrast, the second configuration was chosen to study the usefulness of colour or intensity information in connection with 3D point clouds (“coloured point clouds”), both for improved 3D resolution (“super resolution”) and approaches to the fundamental problems of navigation that exploit the complementary strengths of visual and range information.

    Considering the omni-directional camera/odometry setup, the first part introduces a new registration method based on a measure of image similarity. This registration method is then used to develop a localisation method, which is robust to the changes in dynamic environments, and a visual approach to metric SLAM, which does not require position estimation of local image features and thus provides a very efficient approach.

    The second part, which considers a standard camera together with a 3D laser range scanner, starts with the proposal and evaluation of non-iterative interpolation methods. These methods use colour information from the camera to obtain range information at the resolution of the camera image, or even with sub-pixel accuracy, from the low resolution range information provided by the range scanner. Based on the ability to determine depth values for local visual features, a new registration method is then introduced, which combines the depth of local image features and variance estimates obtained from the 3D laser range scanner to realise a vision-aided 6D registration method, which does not require an initial pose estimate. This is possible because of the discriminative power of the local image features used to determine point correspondences (data association). The vision-aided registration method is further developed into a 6D SLAM approach where the optimisation constraint is based on distances of paired local visual features. Finally, the methods introduced in the second part are combined with a novel adaptive normal distribution transform (NDT) representation of coloured 3D point clouds into a robotic difference detection system.

  • 10.
    Andreasson, Henrik
    et al.
    Örebro University, Department of Technology.
    Duckett, Tom
    University of Lincoln.
    Lilienthal, Achim J.
    A Minimalistic Approach to Appearance-Based Visual SLAM2008In: IEEE Transactions on Robotics, ISSN 1552-3098, Vol. 24, no 5, p. 991-1001Article in journal (Refereed)
    Abstract [en]

    This paper presents a vision-based approach to SLAM in indoor / outdoor environments with minimalistic sensing and computational requirements. The approach is based on a graph representation of robot poses, using a relaxation algorithm to obtain a globally consistent map. Each link corresponds to a relative measurement of the spatial relation between the two nodes it connects. The links describe the likelihood distribution of the relative pose as a Gaussian distribution. To estimate the covariance matrix for links obtained from an omni-directional vision sensor, a novel method is introduced based on the relative similarity of neighbouring images. This new method does not require determining distances to image features using multiple view geometry, for example. Combined indoor and outdoor experiments demonstrate that the approach can handle qualitatively different environments (without modification of the parameters), that it can cope with violations of the “flat floor assumption” to some degree, and that it scales well with increasing size of the environment, producing topologically correct and geometrically accurate maps at low computational cost. Further experiments demonstrate that the approach is also suitable for combining multiple overlapping maps, e.g. for solving the multi-robot SLAM problem with unknown initial poses.

  • 11.
    Andreasson, Henrik
    et al.
    Örebro University, Department of Technology.
    Duckett, Tom
    University of Lincoln, United Kingdom.
    Lilienthal, Achim J.
    Örebro University, Department of Technology.
    Mini-SLAM: minimalistic visual SLAM in large-scale environments based on a new interpretation of image similarity2007In: 2007 IEEE international conference on robotics and automation (ICRA), 2007, p. 4096-4101Conference paper (Refereed)
    Abstract [en]

    This paper presents a vision-based approach to SLAM in large-scale environments with minimal sensing and computational requirements. The approach is based on a graphical representation of robot poses and links between the poses. Links between the robot poses are established based on odometry and image similarity, then a relaxation algorithm is used to generate a globally consistent map. To estimate the covariance matrix for links obtained from the vision sensor, a novel method is introduced based on the relative similarity of neighbouring images, without requiring distances to image features or multiple view geometry. Indoor and outdoor experiments demonstrate that the approach scales well to large-scale environments, producing topologically correct and geometrically accurate maps at minimal computational cost. Mini-SLAM was found to produce consistent maps in an unstructured, large-scale environment (the total path length was 1.4 km) containing indoor and outdoor passages.

  • 12.
    Andreasson, Henrik
    et al.
    Örebro University, Department of Technology.
    Lilienthal, Achim J.
    aass.
    Vision aided 3D laser scanner based registration2007In: Proceedings of the European Conference on Mobile Robots, ECMR (2007), 2007, p. 192-197Conference paper (Refereed)
    Abstract [en]

    This paper describes a vision and 3D laser based registration approach which utilizes visual features to identify correspondences. Visual features are obtained from the images of a standard color camera and the depth of these features is determined by interpolating between the scanning points of a 3D laser range scanner, taking into consideration the visual information in the neighbourhood of the respective visual feature. The 3D laser scanner is also used to determine a position covariance estimate of the visual feature. To exploit these covariance estimates, an ICP algorithm based on the Mahalanobis distance is applied. Initial experimental results are presented in a real world indoor laboratory environment

  • 13.
    Andreasson, Henrik
    et al.
    Örebro University, Department of Technology.
    Lilienthal, Achim J.
    Örebro University, Department of Technology.
    Vision based interpolation of 3D laser scans2006Conference paper (Refereed)
    Abstract [en]

    3D range sensors, particularly 3D laser range scanners, enjoy a rising popularity and are used nowadays for many different applications. The resolution 3D range sensors provide in the image plane is typically much lower than the resolution of a modern color camera. In this paper we focus on methods to derive a high-resolution depth image from a low-resolution 3D range sensor and a color image. The main idea is to use color similarity as an indication of depth similarity, based on the observation that depth discontinuities in the scene often correspond to color or brightness changes in the camera image. We present five interpolation methods and compare them with an independently proposed method based on Markov Random Fields. The algorithms proposed in this paper are non-iterative and include a parameter-free vision-based interpolation method. In contrast to previous work, we present ground truth evaluation with real world data and analyse both indoor and outdoor data. Further, we suggest and evaluate four methods to determine a confidence measure for the accuracy of interpolated range values.

  • 14.
    Andreasson, Henrik
    et al.
    Örebro University, Department of Technology.
    Magnusson, Martin
    Örebro University, Department of Technology.
    Lilienthal, Achim J.
    aass.
    Has something changed here?: Autonomous difference detection for security patrol robots2007In: IEEE/RSJ international conference on intelligent robots and systems, 2007. IROS 2007, 2007, p. 3429-3435Conference paper (Refereed)
    Abstract [en]

    This paper presents a system for autonomous change detection with a security patrol robot. In an initial step a reference model of the environment is created and changes are then detected with respect to the reference model as differences in coloured 3D point clouds, which are obtained from a 3D laser range scanner and a CCD camera. The suggested approach introduces several novel aspects, including a registration method that utilizes local visual features to determine point correspondences (thus essentially working without an initial pose estimate) and the 3D-NDT representation with adaptive cell size to efficiently represent both the spatial and colour aspects of the reference model. Apart from a detailed description of the individual parts of the difference detection system, a qualitative experimental evaluation in an indoor lab environment is presented, which demonstrates that the suggested system is able register and detect changes in spatial 3D data and also to detect changes that occur in colour space and are not observable using range values only.

  • 15.
    Andreasson, Henrik
    et al.
    Örebro University, Department of Technology.
    Treptow, André
    University of Tübingen.
    Duckett, Tom
    Örebro University, Department of Technology.
    Localization for mobile robots using panoramic vision, local features and particle filter2005In: Proceedings of the 2005 IEEE International Converence on Robotics and Automation: ICRA - 2005, 2005, p. 3348-3353Conference paper (Refereed)
    Abstract [en]

    In this paper we present a vision-based approach to self-localization that uses a novel scheme to integrate featurebased matching of panoramic images with Monte Carlo localization. A specially modified version of Lowe’s SIFT algorithm is used to match features extracted from local interest points in the image, rather than using global features calculated from the whole image. Experiments conducted in a large, populated indoor environment (up to 5 persons visible) over a period of several months demonstrate the robustness of the approach, including kidnapping and occlusion of up to 90% of the robot’s field of view.

  • 16.
    Andreasson, Henrik
    et al.
    Örebro University, Department of Technology.
    Treptow, André
    University of Tübingen.
    Duckett, Tom
    Örebro University, Department of Technology.
    Self-localization in non-stationary environments using omni-directional vision2007In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 55, no 7, p. 541-551Article in journal (Refereed)
    Abstract [en]

    This paper presents an image-based approach for localization in non-static environments using local feature descriptors, and its experimental evaluation in a large, dynamic, populated environment where the time interval between the collected data sets is up to two months. By using local features together with panoramic images, robustness and invariance to large changes in the environment can be handled. Results from global place recognition with no evidence accumulation and a Monte Carlo localization method are shown. To test the approach even further, experiments were conducted with up to 90% virtual occlusion in addition to the dynamic changes in the environment

  • 17.
    Andreasson, Henrik
    et al.
    Örebro University, Department of Technology.
    Triebel, Rudolph
    University of Friburg.
    Burgard, Wolfram
    University of Friburg.
    Improving plane extraction from 3D data by fusing laser data and vision2005In: 2005 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2005. (IROS 2005): IROS 2005 IEEE/RSJ, 2005, p. 2656-2661Conference paper (Refereed)
    Abstract [en]

    The problem of extracting three-dimensional structures from data acquired with mobile robots has received considerable attention over the past years. Robots that are able to perceive their three-dimensional environment are envisioned to more robustly perform tasks like navigation, rescue, and manipulation. In this paper we present an approach that simultaneously uses color and range information to cluster 3d points into planar structures. Our current system also is able to calibrate the camera and the laser based on the remission values provided by the range scanner and the brightness of the pixels in the image. It has been implemented on a mobile robot equipped with a manipulator that carries a range scanner and a camera for acquiring colored range scans. Several experiments carried out on real data and in simulations demonstrate that our approach yields highly accurate results also in comparison with previous approaches

  • 18.
    Andreasson, Henrik
    et al.
    Örebro University, Department of Technology.
    Triebel, Rudolph
    University of Freiburg, Germany.
    Lilienthal, Achim J.
    Örebro University, Department of Technology.
    Non-iterative Vision-based Interpolation of 3D Laser Scans2007In: Autonomous Robots and Agents, Berlin / Heidelberg: Springer , 2007, Vol. 76, p. 83-90Chapter in book (Other academic)
    Abstract [en]

    3D range sensors, particularly 3D laser range scanners, enjoy a rising popularity and are used nowadays for many different applications. The resolution 3D range sensors provide in the image plane is typically much lower than the resolution of a modern colour camera. In this chapter we focus on methods to derive a highresolution depth image from a low-resolution 3D range sensor and a colour image. The main idea is to use colour similarity as an indication of depth similarity, based on the observation that depth discontinuities in the scene often correspond to colour or brightness changes in the camera image. We present five interpolation methods and compare them with an independently proposed method based on Markov random fields. The proposed algorithms are non-iterative and include a parameter-free vision-based interpolation method. In contrast to previous work, we present ground truth evaluation with real world data and analyse both indoor and outdoor data

  • 19.
    Arén, Björn
    Örebro University, Department of Technology.
    Die Stresses in the compaction of powders: experiments and analysis2004Conference paper (Refereed)
  • 20.
    Arén, Björn
    Örebro University, Department of Technology.
    Dimensioning of dies for the compaction of shaped PM-parts2003Conference paper (Refereed)
  • 21. Bahadori, Shahram
    et al.
    Cesta, Amedeo
    Grisetti, Giorgio
    Iocchi, Luca
    Leone, Riccardo G.
    Nardi, Daniele
    Oddi, Angelo
    Pecora, Federico
    Örebro University, Department of Technology.
    Rasconi, Riccardo
    Robocare: an integrated robotic system for the domestic care of the elderly2003Conference paper (Refereed)
  • 22. Bahadori, Shahram
    et al.
    Cesta, Amedeo
    Iocchi, Luca
    Leone, Riccardo G.
    Nardi, Daniele
    Pecora, Federico
    Örebro University, Department of Technology.
    Rasconi, Riccardo
    Scozzafava, L.
    Towards ambient intelligence for the domestic care of the elderly2005In: Ambient intelligence: a novel paradigm / [ed] Gian Luca Foresti, Tim Ellis, Springer Berlin/Heidelberg, 2005, p. 15-38Chapter in book (Refereed)
  • 23. Benedetti, Marco
    et al.
    Pecora, Federico
    Örebro University, Department of Technology.
    Policella, Nicola
    Anatomy of a scheduling competition2007Conference paper (Refereed)
  • 24.
    Benferhat, Salem
    et al.
    Univ. Paul Sabatier, Toulouse, France.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Smets, Philippe
    Univ. Libre de Bruxelles, Brussels, Belgium.
    Belief functions and default reasoning2000In: Artificial Intelligence, ISSN 0004-3702, E-ISSN 1872-7921, Vol. 122, no 1-2, p. 1-69Article in journal (Refereed)
    Abstract [en]

    We present a new approach to deal with default information based on the theory of belief functions. Our semantic structures, inspired by Adams' epsilon semantics, are epsilon-belief assignments, where mass values are either close to 0 or close to 1. In the first part of this paper, we show that these structures can be used to give a uniform semantics to several popular non-monotonic systems, including Kraus, Lehmann and Magidor's system P, Pearl's system Z, Brewka's preferred sub-theories, Geffner's conditional entailment, Pinkas' penalty logic, possibilistic logic, and the lexicographic approach. In the second part, we use epsilon-belief assignments to build a new system, called LCD, and we show that this system correctly addresses the well-known problems of specificity, irrelevance, blocking of inheritance, ambiguity, and redundancy

  • 25.
    Bennewitz, Maren
    et al.
    University of Freiburg.
    Burgard, Wolfram
    University of Freiburg.
    Cielniak, Grzegorz
    Örebro University, Department of Technology.
    Thrun, Sebastian
    Carnegie Mellon University.
    Learning motion patterns of people for compliant robot motion2005In: The international journal of robotics research, ISSN 0278-3649, E-ISSN 1741-3176, Vol. 24, no 1, p. 31-48Article in journal (Refereed)
    Abstract [en]

    Whenever people move through their environments they do not move randomly. Instead, they usually follow specific trajectories or motion patterns corresponding to their intentions. Knowledge about such patterns enables a mobile robot to robustly keep track of persons in its environment and to improve its behavior. This paper proposes a technique for learning collections of trajectories that characterize typical motion patterns of persons. Data recorded with laser-range finders is clustered using the expectation maximization algorithm. Based on the result of the clustering process we derive a Hidden Markov Model (HMM) that is applied to estimate the current and future positions of persons based on sensory input. We also describe how to incorporate the probabilistic belief about the potential trajectories of persons into the path planning process. We present several experiments carried out in different environments with a mobile robot equipped with a laser range scanner and a camera system. The results demonstrate that our approach can reliably learn motion patterns of persons, can robustly estimate and predict positions of persons, and can be used to improve the navigation behavior of a mobile robot.

  • 26.
    Bergsten, Pontus
    Örebro University, Department of Technology.
    Observers and controllers for Takagi-Sugeno fuzzy systems2001Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis studies analysis and design issues for observers anc controllers for Takagi-Sugeno (TS) fuzzy systems. Many physical systems are nonlinear in nature and using the well known linear techniques for such systems may result in bad performance, and even instability. On the other hand, analysis and design of observers and controllers for general nonlinear systems tend to be a quite involved procedure. It turns out, however, that a TS fuzzy system is able to represent or approximate a large class of nonlinear systems. Developing methods for observation and control for TS systems should therefore be worthwile.

    The TS fuzzy systems considered in this thesis are allowed to have an affine term. This can be an advantage, because affine TS fuzzy systems may be able to approximate nonlinear functions  to high accuracy with fewer rules than the TS fuzzy system with linear consequents only.

    It is shown that observer design is more difficult when the weights in the TS fuzzy systems depend on the estimated state, and an explicit design procedure is devised for that case. A reduced order observer is also proposed. To deal with modeling errors a fuzzy sliding mode approach is taken.

    The controller design is focused on affine TS fuzzy systems. Analysis and design of observer-based error state feedback controllers are proposed. Furthermore, it is also shown how recent results on classical gain scheduling may be used for control of affine TS fuzzy systems.

    Analysis and design for both observers and controllers are based on quadratic stability analysis, and in some cases, on robust quadratic stability analysis. Although this approach may be conservative, it often results in automatic design procedures based on optimization subject to linear matrix inequalities.

  • 27.
    Bergsten, Pontus
    et al.
    Örebro University, Department of Technology.
    Palm, Rainer
    Siemens AG Corporate Technology, Munich, Germany.
    Driankov, Dimiter
    Örebro University, Department of Technology.
    Fuzzy Observers2001In: The 10th IEEE International Conference on Fuzzy Systems (Volym:3): Meeting the grand challenge: Machines that serve people, New York, USA: IEEE conference proceedings, 2001, p. 700-703Conference paper (Refereed)
    Abstract [en]

    We consider the analysis and design of three different types of nonlinear observers for dynamic Takagi-Sugeno fuzzy systems. Our approach is based on extending existing nonlinear observer schemes, namely Thau-Luenberger and sliding mode observers, to the case of interpolated multiple local affine linear models. Then linear matrix inequality based techniques are used for observer analysis and design.

  • 28.
    Berntsson, Tomas
    Örebro University, Department of Technology.
    Anlöpning utan bly2002Conference paper (Other academic)
  • 29.
    Berntsson, Tomas
    Örebro University, Department of Technology.
    Replacement of lead baths with environment friendly alternative heat treatment processes in steel wire production2005Licentiate thesis, comprehensive summary (Other academic)
    List of papers
    1. Replacement of lead baths for the tempering of spring wire
    Open this publication in new window or tab >>Replacement of lead baths for the tempering of spring wire
    2003 (English)In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 32, no 5, p. 241-246Article in journal (Refereed) Published
    Abstract [en]

    Molten lead is used for tempering of valve-spring wire. Lead has drawbacks due to slow temperature changes. In 1991 the Swedish Parliament passed a Government Bill, in which proposals were made to phase out the use of lead in the long term, primarily through voluntary measures. Tempering of SIS 2090 (SAE 9254, DIN 55SiCr7) wire with different dimensions using induction heating was tested in a pilot process line. An induction coil for six wires and two coils with different lengths designed for single wires were tested. The results showed that an induction coil for six wires gave excessive temperature and property variations between the wires. The shorter of the single wire coils gave fluctuations in temperature and properties using a 3.00-mm wire. No such fluctuations were observed with the longer coil. One of the experiments showed that the process might need time to reach stable conditions. The results so far indicate that it is possible to produce valve-spring wire with induction tempering. The process needs more control and monitoring compared to tempering in molten lead. © Blackwell Munksgaard, 2003.

    Keyword
    Automotive engineering, Lead, Wire, Monitoring
    National Category
    Engineering and Technology
    Research subject
    Mechanical Engineering
    Identifiers
    urn:nbn:se:oru:diva-4615 (URN)10.1034/j.1600-0692.2003.00648.x (DOI)
    Available from: 2007-07-12 Created: 2007-07-12 Last updated: 2017-12-14Bibliographically approved
    2. Alternatives to lead bath for patenting of high carbon steel wire
    Open this publication in new window or tab >>Alternatives to lead bath for patenting of high carbon steel wire
    2004 (English)In: Wire Journal International, ISSN 0277-4275, Vol. 37, no 5, p. 82-86Article in journal (Refereed) Published
    Abstract [en]

    The alternatives to lead bath for patenting of high carbon steel wire are discussed. It is found that it is possible to achieve properties of high-speed gas patented music wire without using a soaking furnace. Laboratory experiments with patenting in a fluidized bed, showed that the process could give the required mechanical properties for the valve spring wire. It is also found that small alterations in process parameters in the industrial trials has a large impact on the mechanical properties and microstructures.

    Keyword
    Carbon steel, Furnaces, Austenite, Mufflers, Wire drawing, Molten materials, Valves (mechanical), Quenching, Process control, High temperature effects
    Research subject
    Mechanical Engineering
    Identifiers
    urn:nbn:se:oru:diva-4582 (URN)
    Available from: 2007-07-12 Created: 2007-07-12 Last updated: 2017-10-18Bibliographically approved
    3. Material properties of induction tempered high tensile valve spring wire
    Open this publication in new window or tab >>Material properties of induction tempered high tensile valve spring wire
    2006 (English)In: Steel Research International, ISSN 1611-3683, Vol. 77, no 11, p. 836-843Article in journal (Refereed) Published
    Abstract [en]

    Most of today's hardened valve spring wires are tempered in a lead bath. The lead bath provides a stable and accurate degree of tempering of the wire, but it has environmental disadvantages and limitations in flexibility. This paper describes how induction heating can replace lead bath and how this may affect the material properties. The study includes FEM-simulations, calculation of the tempering parameter and experiments with induction tempering of three different SiCr valve spring steels carried out under pilot production. The mechanical properties of the test samples were measured. Fatigue testing of one of the steels was performed on finished springs. The results were evaluated by comparing induction-tempered wire with the conventional lead tempered reference wire. The induction tempered wire fulfilled the product requirements and corresponded in performance with the lead tempered wire.

    Place, publisher, year, edition, pages
    Düsseldorf: Verlag Stahleisen, 2006
    Keyword
    Wire, Valves (mechanical), Tempering, Lead, Thermoanalysis, Steel, Finite element method, Computer simulation, Induction tempering, Spring steel, Super clean steel, High strength steel, Silicon chromium steel
    National Category
    Engineering and Technology
    Research subject
    maskinteknik
    Identifiers
    urn:nbn:se:oru:diva-4387 (URN)
    Available from: 2007-07-12 Created: 2007-07-12 Last updated: 2017-10-18Bibliographically approved
  • 30.
    Berntsson, Tomas
    et al.
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Alternativ till bly vid värmebehandling av tråd: sammanfattning2003Report (Other academic)
  • 31.
    Berntsson, Tomas
    et al.
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Material properties of induction tempered high tensile valve spring wire2006In: Steel Research International, ISSN 1611-3683, Vol. 77, no 11, p. 836-843Article in journal (Refereed)
    Abstract [en]

    Most of today's hardened valve spring wires are tempered in a lead bath. The lead bath provides a stable and accurate degree of tempering of the wire, but it has environmental disadvantages and limitations in flexibility. This paper describes how induction heating can replace lead bath and how this may affect the material properties. The study includes FEM-simulations, calculation of the tempering parameter and experiments with induction tempering of three different SiCr valve spring steels carried out under pilot production. The mechanical properties of the test samples were measured. Fatigue testing of one of the steels was performed on finished springs. The results were evaluated by comparing induction-tempered wire with the conventional lead tempered reference wire. The induction tempered wire fulfilled the product requirements and corresponded in performance with the lead tempered wire.

  • 32.
    Berntsson, Tomas
    et al.
    Örebro University, Department of Technology.
    Sapcanin, Edin
    Örebro University, Department of Technology.
    Alternativ till bly vid värmebehandling av tråd: examensarbete2003Report (Other academic)
  • 33.
    Berntsson, Tomas
    et al.
    Örebro University, Department of Technology.
    Sapcanin, Edin
    Örebro University, Department of Technology.
    Alternativ till bly vid värmebehandling av tråd: slutrapport2003Report (Other academic)
  • 34.
    Berntsson, Tomas
    et al.
    Örebro University, Department of Technology.
    Sapcanin, Edin
    Örebro University, Department of Technology.
    Kontinuerlig patentering av pianotråd med gaskylning: delrapport2003Report (Other academic)
  • 35.
    Berntsson, Tomas
    et al.
    Örebro University, Department of Technology.
    Sapcanin, Edin
    Örebro University, Department of Technology.
    Patentering av tråd i virvelbädd och med gaskylning: delrapport2003Report (Other academic)
  • 36.
    Berntsson, Tomas
    et al.
    Örebro University, Department of Technology.
    Sapcanin, Edin
    Örebro University, Department of Technology.
    Hede, Allan
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Alternatives to lead bath for heat treatment of wire2003Conference paper (Other academic)
  • 37.
    Berntsson, Tomas
    et al.
    Örebro University, Department of Technology.
    Sapcanin, Edin
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Blyfri värmebehandling av tråd2002In: Stål 2002, 2002, p. 50-51Conference paper (Other academic)
  • 38.
    Berntsson, Tomas
    et al.
    Örebro University, Department of Technology.
    Sapcanin, Edin
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Segerberg, Sören
    Alternatives to lead bath for patenting of high carbon steel wire2003Conference paper (Refereed)
  • 39.
    Berntsson, Tomas
    et al.
    Örebro University, Department of Technology.
    Sapcanin, Edin
    Örebro University, Department of Technology.
    Jarl, Magnus
    Örebro University, Department of Technology.
    Segerberg, Sören
    Alternatives to lead bath for patenting of high carbon steel wire2004In: Wire Journal International, ISSN 0277-4275, Vol. 37, no 5, p. 82-86Article in journal (Refereed)
    Abstract [en]

    The alternatives to lead bath for patenting of high carbon steel wire are discussed. It is found that it is possible to achieve properties of high-speed gas patented music wire without using a soaking furnace. Laboratory experiments with patenting in a fluidized bed, showed that the process could give the required mechanical properties for the valve spring wire. It is also found that small alterations in process parameters in the industrial trials has a large impact on the mechanical properties and microstructures.

  • 40.
    Biel, Lena
    Örebro University, Department of Technology.
    Modeling of perceptual systems: a sensor fusion model with active perception2002Licentiate thesis, comprehensive summary (Other academic)
    List of papers
    1. ECG analysis: a new approach in human identification
    Open this publication in new window or tab >>ECG analysis: a new approach in human identification
    2001 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    In this paper a new approach in human identification is investigated, For this purpose, a standard 12-lead electrocardiogram (ECG) recorded during rest is used. Selected features extracted from the ECG are used to identify a person in a predetermined group. Multivariate analysis is used for the identification task. Experiments show that it is possible to identify a person by features extracted from one lead only. Hence, only three electrodes have to be attached on the person to be identified. This makes the method applicable without too much effort.

    Keyword
    data fusion, electrocardiogram (ECG), feature extraction, human identification, multivariate analysis
    National Category
    Computer Sciences
    Research subject
    Computer and Systems Science
    Identifiers
    urn:nbn:se:oru:diva-16067 (URN)000169439600022 ()
    Available from: 2011-06-22 Created: 2011-06-22 Last updated: 2018-01-12Bibliographically approved
    2. Multivariate sensor fusion by a neural network model
    Open this publication in new window or tab >>Multivariate sensor fusion by a neural network model
    (English)Manuscript (preprint) (Other academic)
    National Category
    Computer Sciences
    Research subject
    Computer and Systems Science
    Identifiers
    urn:nbn:se:oru:diva-16070 (URN)
    Available from: 2011-06-22 Created: 2011-06-22 Last updated: 2018-01-12Bibliographically approved
    3. Active perception for autonomous sensor systems: an emerging paradigm?
    Open this publication in new window or tab >>Active perception for autonomous sensor systems: an emerging paradigm?
    2000 (English)Manuscript (preprint) (Other academic)
    National Category
    Computer Sciences
    Research subject
    Computer and Systems Science
    Identifiers
    urn:nbn:se:oru:diva-16068 (URN)000165444800008 ()
    Available from: 2011-06-22 Created: 2011-06-22 Last updated: 2018-01-12Bibliographically approved
    4. Active perception in a sensor fusion model
    Open this publication in new window or tab >>Active perception in a sensor fusion model
    2002 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    During the last decades the research in the sensor fusion area has mainly been focused on fusion methods and feature selection methods. A possible further development in this area is to incorporate a process referred to as active perception. This means that the system is able to manipulate the sensing mechanisms to create a focus on selected information in the surrounding environment. This process may also be able to handle the feature selection process with respect to which features to be used and/or the number of features to use. This paper presents a model that contains a decision system based on active perception integrated with previous sensor fusion algorithms. The human body has perhaps one of the most advanced perceptual processing systems. The human perception process can be divided into sensation (measurement collection) and perception (interpret the surroundings). During the sensation process a huge amount of data is collected from different sensors that reflect the environment. The information has to be interpreted in an effective way, i.e. in the fusion process. The interpretation together with a decision system to control the sensors to focus on important information will correspond to the (active) perception process. The model presented in this paper capitalizes on the properties presented by the biological counterpart to achieve more human-like processes for a sensor fusion. Finally, the paper presents the testing of the model in two examples. The applications used have a safety approach of fire indication, identification and decision-making. The goal is to enlarge a conventional fire alarm system to not only detect fire, but also to propose different actions for a human in a dangerous area for example.

    National Category
    Computer Sciences
    Research subject
    Computer and Systems Science
    Identifiers
    urn:nbn:se:oru:diva-16066 (URN)000176995000017 ()
    Available from: 2011-06-22 Created: 2011-06-22 Last updated: 2018-01-12Bibliographically approved
  • 41.
    Biel, Lena
    et al.
    Örebro University, Department of Technology.
    Pettersson, Ola
    Örebro University, Department of Technology.
    Philipson, Lennart
    Örebro University, Department of Technology.
    Wide, Peter
    Örebro University, Department of Technology.
    ECG analysis: a new approach in human identification2001Manuscript (preprint) (Other academic)
    Abstract [en]

    In this paper a new approach in human identification is investigated, For this purpose, a standard 12-lead electrocardiogram (ECG) recorded during rest is used. Selected features extracted from the ECG are used to identify a person in a predetermined group. Multivariate analysis is used for the identification task. Experiments show that it is possible to identify a person by features extracted from one lead only. Hence, only three electrodes have to be attached on the person to be identified. This makes the method applicable without too much effort.

  • 42.
    Biel, Lena
    et al.
    Örebro University, Department of Technology.
    Wide, Peter
    Örebro University, Department of Technology.
    Active perception for autonomous sensor systems: an emerging paradigm?2000Manuscript (preprint) (Other academic)
  • 43.
    Biel, Lena
    et al.
    Örebro University, Department of Technology.
    Wide, Peter
    Örebro University, Department of Technology.
    Active perception in a sensor fusion model2002Manuscript (preprint) (Other academic)
    Abstract [en]

    During the last decades the research in the sensor fusion area has mainly been focused on fusion methods and feature selection methods. A possible further development in this area is to incorporate a process referred to as active perception. This means that the system is able to manipulate the sensing mechanisms to create a focus on selected information in the surrounding environment. This process may also be able to handle the feature selection process with respect to which features to be used and/or the number of features to use. This paper presents a model that contains a decision system based on active perception integrated with previous sensor fusion algorithms. The human body has perhaps one of the most advanced perceptual processing systems. The human perception process can be divided into sensation (measurement collection) and perception (interpret the surroundings). During the sensation process a huge amount of data is collected from different sensors that reflect the environment. The information has to be interpreted in an effective way, i.e. in the fusion process. The interpretation together with a decision system to control the sensors to focus on important information will correspond to the (active) perception process. The model presented in this paper capitalizes on the properties presented by the biological counterpart to achieve more human-like processes for a sensor fusion. Finally, the paper presents the testing of the model in two examples. The applications used have a safety approach of fire indication, identification and decision-making. The goal is to enlarge a conventional fire alarm system to not only detect fire, but also to propose different actions for a human in a dangerous area for example.

  • 44. Bloch, I.
    et al.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    On the representation of fuzzy spatial relations in robot maps2003In: Intelligent systems for information processing: from representation to applications / [ed] Bernadette Bouchon-Meunier, Laurent Foulloy, Ronald R. Yager, Amsterdam: Elsevier, 2003, p. 47-57Conference paper (Refereed)
    Abstract [en]

    Spatial directional relations, like "north of," play an important role in the modeling of the environment by an autonomous robot. We propose an approach to represent spatial relations grounded in fuzzy set theory and fuzzy mathematical morphology. We show how this approach can be applied to robot maps, and suggest that these relations can be used for self-localization and for reasoning about the environment. We illustrate our approach on real data collected by a mobile robot in an office environment

  • 45. Bloch, Isabelle
    et al.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Why robots should use fuzzy mathematical morphology2002Conference paper (Refereed)
    Abstract [en]

    Mobile robots must represent and reason about spatial knowledge acquired from sensor data which are inherently approximate and uncertain. While techniques based on fuzzy sets are increasingly used in this domain, the use of these techniques often rests on intuitive grounds. In this paper, we show that fuzzy mathematical morphology, a theory often used in image processing but mostly ignored in the robotic tradition, can provide a well grounded approach to the treatment of imprecise spatial knowledge in robotics

  • 46.
    Boldrin, Luca
    et al.
    University of Pauda.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    A modal logic for fusing partial belief of multiple reasoners1999In: Journal of logic and computation (Print), ISSN 0955-792X, E-ISSN 1465-363X, Vol. 9, no 1, p. 81-103Article in journal (Refereed)
    Abstract [en]

    We present PLn, a multi-agent epistemic logic in which each agent can perform uncertain (possibilistic) reasoning. The original feature of this logic is the presence of a distributed belief operator, with the purpose of merging the belief of different agents. Unlike the corresponding operator in the categorical (non-uncertain) case, our distributed belief operator accumulates support for the same fact coming from different agents. This means that opinions shared by different agents can be combined into a stronger distributed belief. This feature is useful in problems like pooling expert opinions and combining information from multiple unreliable sources. We provide a possible worlds semantics and an axiomatic calculus for our logic, and prove soundness, completeness and decidability results. We hint at some possible applications of PLn in the conclusions

  • 47.
    Bordignon, Mirko
    et al.
    Dept. of Information Engineering, University of Padova, Italy.
    Pagello, Enrico
    Dept. of Information Engineering, University of Padova, Italy.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    An inexpensive, off-the-shelf platform for networked embedded robotics2007In: Proceedings of the 1st international conference on Robot communication and coordination, RoboComm '07, Piscataway: IEEE press , 2007, p. Art no: 45-Conference paper (Refereed)
    Abstract [en]

    Recent years have witnessed the proliferation of a new class of devices, commonly referred to as Networked Embedded Devices. Their increasingly low cost and small size make them suited for large scale sensing applications. Likewise, they could be appealing as a means to embed intelligent actuation capabilities into the environment, turning simple artifacts into networked robotic appliances. The currently existing devices, however, are not suited for this development. In this paper, we present the PEIS-Mote: an open, general, small-size and inexpensive sensor-actuator node especially suited for networked robotics, and built from commonly available off-the-shelf components. This platform can run a popular operating system for sensor networks, TinyOS, which makes it interoperable with most commercially available sensor nodes.

  • 48. Bordignon, Mirko
    et al.
    Rashid, Jayedur
    Örebro University, Department of Technology.
    Broxvall, Mathias
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Seamless integration of robots and tiny embedded devices in a PEIS-ecology2007In: IEEE/RSJ international  conference on intelligent robots and systems, IROS 2007, New York: IEEE , 2007, p. 3101-3106Conference paper (Refereed)
    Abstract [en]

    The fields of autonomous robotics and ambient intelligence are converging toward the vision of smart robotic environments, in which tasks are performed via the cooperation of many networked robotic devices. To enable this vision, we need a common communication and cooperation model that can be shared between robotic devices at different scales, ranging from standard mobile robots to tiny embedded devices. Unfortunately, today's robot middlewares are too heavy to run on tiny devices, and middlewares for embedded devices are too simple to support the cooperation models needed by an autonomous smart environment. In this paper, we propose a middleware model which allows the seamless integration of standard robots and simple off-the-shelf embedded devices. Our middleware is suitable for building truly ubiquitous robotics applications, in which devices of very different scales and capabilities can cooperate in a uniform way. We discuss the principles and implementation of our middleware, and show an experiment in which a mobile robot, a commercial mote, and a custom-built mote cooperate in a home service scenario.

  • 49.
    Bothe, Hans-H.
    et al.
    Örebro University, Department of Technology.
    Persson, Martin
    Örebro University, Department of Technology.
    Biel, Lena
    Örebro University, Department of Technology.
    Rosenholm, Magnus
    Örebro University, Department of Technology.
    Multivariate sensor fusion by a neural network modelManuscript (preprint) (Other academic)
  • 50.
    Bouguerra, Abdel
    et al.
    Örebro University, Department of Technology.
    Karlsson, Lars
    Örebro University, Department of Technology.
    PC-SHOP: a probabilstic-conditional hierarchical task planner2005In: Intelligenza Artificiale, ISSN 1724-8035, Vol. 2, no 4, p. 44-50Article in journal (Refereed)
    Abstract [en]

    In this paper we report on the extension of the classical HTN planner SHOP to plan in partially observable domains with uncertainty. Our algorithm PC-SHOP uses belief states to handle situations involving incomplete and uncertain information about the state of the world. Sensing and acting are integrated in the primitive actions through the use of a stochastic model. PC-SHOP is showed to scale up well compared to some of the state-of-the-art planners. We outline the main characteristics of the algorithm, and present performance results on some problems found in the literature.

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