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  • 51.
    Banaee, Hadi
    et al.
    Örebro University, School of Science and Technology.
    Ahmed, Mobyen Uddin
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Towards NLG for Physiological Data Monitoring with Body Area Networks2013In: 14th European Workshop on Natural Language Generation, 2013, p. 193-197Conference paper (Refereed)
    Abstract [en]

    This position paper presents an on-goingwork on a natural language generationframework that is particularly tailored fornatural language generation from bodyarea networks. We present an overview ofthe main challenges when considering thistype of sensor devices used for at homemonitoring of health parameters. The paperpresents the first steps towards the implementationof a system which collectsinformation from heart rate and respirationusing a wearable sensor.

  • 52.
    Bandaru, Vamsi Krishna
    et al.
    Örebro University, School of Science and Technology.
    Balasubramanian, Rajasekaran
    Örebro University, School of Science and Technology.
    OBJECT RECOGNITION USINGDIALOGUES AND SEMANTICANCHORING2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report explains in detail the implemented system containing a robot and a sensor

    network that is deployed in a test apartment in an elderly residence area. The report

    focuses on the creation and maintenance (anchoring) of the connection between the

    semantic information present in the dialog with perceived actual physical objects in the

    home. Semantic knowledge about concepts and their correlations are retrieved from online

    resources and ontologies, e.g. Word-Net and sensors information are provided by

    cameras distributed in the apartment.

  • 53.
    Beeson, Patrick
    et al.
    TRACLabs Inc., Webster TX, USA.
    Kortenkamp, David
    TRACLabs Inc., Webster TX, USA.
    Bonasso, R. Peter
    TRACLabs Inc., Webster TX, USA.
    Persson, Andreas
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Bona, Jonathan P
    State University of New York, Buffalo, USA.
    An Ontology-Based Symbol Grounding System for Human-Robot Interaction2014In: Artificial Intelligence for Human-Robot Interaction: 2014 AAAI Fall Symposium, AAAI Press, 2014Conference paper (Refereed)
    Abstract [en]

    This paper presents an ongoing collaboration to develop a perceptual anchoring framework which creates and maintains the symbol-percept links concerning household objects. The paper presents an approach to non-trivialize the symbol system using ontologies and allow for HRI via enabling queries about objects properties, their affordances, and their perceptual characteristics as viewed from the robot (e.g. last seen). This position paper describes in brief the objective of creating a long term perceptual anchoring framework for HRI and outlines the preliminary work done this far.

  • 54.
    Bennetts, Victor Hernandez
    et al.
    Örebro University, School of Science and Technology.
    Schaffernicht, Erik
    Örebro University, School of Science and Technology.
    Stoyanov, Todor
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Trincavelli, Marco
    Örebro University, School of Science and Technology.
    Robot Assisted Gas Tomography - Localizing Methane Leaks in Outdoor Environments2014In: 2014 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION (ICRA), IEEE conference proceedings, 2014, p. 6362-6367Conference paper (Refereed)
    Abstract [en]

    In this paper we present an inspection robot to produce gas distribution maps and localize gas sources in large outdoor environments. The robot is equipped with a 3D laser range finder and a remote gas sensor that returns integral concentration measurements. We apply principles of tomography to create a spatial gas distribution model from integral gas concentration measurements. The gas distribution algorithm is framed as a convex optimization problem and it models the mean distribution and the fluctuations of gases. This is important since gas dispersion is not an static phenomenon and furthermore, areas of high fluctuation can be correlated with the location of an emitting source. We use a compact surface representation created from the measurements of the 3D laser range finder with a state of the art mapping algorithm to get a very accurate localization and estimation of the path of the laser beams. In addition, a conic model for the beam of the remote gas sensor is introduced. We observe a substantial improvement in the gas source localization capabilities over previous state-of-the-art in our evaluation carried out in an open field environment.

  • 55.
    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.

  • 56.
    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.

  • 57.
    Bergstrand, Simon
    Örebro University, School of Science and Technology.
    Programmering av styrutrustning för vridbord vid radarmätplats2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When calibrating a radars antenna the radar is placed on a turntable that points it to a measuring point on a tower. The main task for the thesis was to write a program in National Instruments programming environment LabVIEW that can turn the turntable with an accuracy of 0.1 milliradians. The program shall be able to be used as a DLL (Dynamic-link library) in LabWindows/CVI where a number of different functions shall be able to control the turntable. Because all of the hardware is from National Instruments the software development became easy. The challenge was instead to measure the lengths and angles of the turntable and at testing be so precise that is necessary. All requirements were met but the lack of accuracy when testing makes the results a bit uncertain.Another part of the thesis was to write documents that specify requirements, interfaces and also describes how the software will be designed, tested and calibrated. For these documents the MIL-STD-498 was used that used to be an American military standard.

  • 58.
    Bergström, Per
    et al.
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Khodadad, Davood
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Hällstig, Emil
    Optronic Partner Dp AB, Skellefteå, Sweden.
    Sjödahl, Mikael
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Dual-wavelength digital holography: single-shot shape evaluation using speckle displacements and regularization2014In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 53, no 1, p. 123-131Article in journal (Refereed)
    Abstract [en]

    This paper discusses the possibility of evaluating the shape of a free-form object in comparison with its shape prescribed by a CAD model. Measurements are made based on a single-shot recording using dual-wavelength holography with a synthetic wavelength of 1.4 mm. Each hologram is numerically propagated to different focus planes and correlated. The result is a vector field of speckle displacements that is linearly dependent on the local distance between the measured surface and the focus plane. From these speckle displacements, a gradient field of the measured surface is extracted through a proportional relationship. The gradient field obtained from the measurement is then aligned to the shape of the CAD model using the iterative closest point (ICP) algorithm and regularization. Deviations between the measured shape and the CAD model are found from the phase difference field, giving a high precision shape evaluation. The phase differences and the CAD model are also used to find a representation of the measured shape. The standard deviation of the measured shape relative the CAD model varies between 7 and 19 μm, depending on the slope.

  • 59.
    Bergström, Per
    et al.
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Khodadad, Davood
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Hällstig, Emil
    Optronic Partner dp AB, Skellefteå, Sweden.
    Sjödahl, Mikael
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Single Shot Shape Evaluation Using Dual-Wavelength Holographic Reconstructions and Regularization2014In: Fringe 2013: 7th International Workshop on Advanced Optical Imaging and Metrology / [ed] Wolfgang Osten, Springer Berlin/Heidelberg, 2014, p. 103-108Conference paper (Refereed)
    Abstract [en]

    The aim of this work is to evaluate the shape of a free form object using single shot digital holography. The digital holography results in a gradient field and wrapped phase maps representing the shape of the object. The task is then to find a surface representation from this data which is an inverse problem. To solve this inverse problem we are using regularization with additional shape information from the CAD-model of the measured object.

  • 60.
    Berna, Amalia
    et al.
    CSIRO Ecosystem Sciences and CSIRO Food Futures Flagship, Canberra, Australian Capital Territory (ACT), Australia.
    Vergara, Alexander
    University of California, San Diego, USA.
    Trincavelli, Marco
    Örebro University, School of Science and Technology.
    Huerta, Ramon
    University of California, San Diego, USA.
    Afonja, Ayo
    Department of Chemistry, University College London, London, UK.
    Parkin, Ivan
    Binions, Russell
    Trowell, Stephen
    Evaluating zeolite-modified sensors: towards a faster set of chemical sensors2011In: Olfaction and electronic nose: proceedings of the 14th International Symposium on Olfaction and Electronic Nose (ISOEN 2011), May 2-5, 2011, New York City, USA, American Institute of Physics (AIP), 2011, p. 50-52Conference paper (Refereed)
    Abstract [en]

    The response of zeolite-modified sensors, prepared by screen printing layers of chromium titanium oxide (CTO), were compared to unmodified tin oxide sensors using amplitude and transient responses. For transient responses we used a family of features, derived from the exponential moving average (EMA), to characterize chemo-resistive responses. All sensors were tested simultaneously against 20 individual volatile compounds from four chemical groups. The responses of the two types of sensors showed some independence. The zeolite modified CTO sensors discriminated compounds better using either amplitude response or EMA features and CTO-modified sensors also responded three times faster.

  • 61. Birk, Andreas
    et al.
    Poppinga, Jann
    Stoyanov, Todor
    Örebro University, School of Science and Technology.
    Nevatia, Yashodhan
    Planetary Exploration in USARSim: A Case Study including Real World Data from Mars2009In: RoboCup 2008: Robot Soccer World Cup XII / [ed] Volume editors: Luca Iocchi, Hitoshi Matsubara, Alfredo Weitzenfeld, Changjiu Zhou, Springer Berlin Heidelberg , 2009, p. 463-472Conference paper (Refereed)
    Abstract [en]

     Intelligent Mobile Robots are increasingly used in unstructured domains; one particularly challenging example for this is, planetary exploration. The preparation of according missions is highly non-trivial, especially as it is difficult to carry out realistic experiments without, very sophisticated infrastructures. In this paper, we argue that, the, Unified System for Automation and Robot Simulation (USARSim) offers interesting opportunities for research on planetary exploration by mobile robots. With the example of work on terrain classification, it, is shown how synthetic as well as real world data, from Mars call be used to test an algorithm's performance in USARSim. Concretely, experiments with an algorithm for the detection of negotiable ground oil a, planetary surface are presented. It is shown that the approach performs fast; and robust on planetary surfaces.

  • 62. Birk, Andreas
    et al.
    Stoyanov, Todor
    Örebro University, School of Science and Technology.
    Nevatia, Yashodhan
    Ambrus, Rares
    Poppinga, Jan
    Pathak, Kaustubh
    Terrain Classification for Autonomous Robot Mobility: from Safety, Security Rescue Robotics to Planetary Exploration2008Conference paper (Refereed)
  • 63.
    Birkelöf, Jonas
    Örebro University, School of Science and Technology.
    Framtagning av demonstratorer2009Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    På Alfred Nobelmuseet i Karlskoga finns en avdelning som kallas Fiffiga huset. Där finns många experiment som besökare kan prova på, samt montrar som visar hur olika tekniska och maskinella apparater fungerar. Till utställningen och öppnandet sommaren 2009 ville de ha två nya demonstratorer. I rapporten kallas dem för reaktionstidsväggen och baklängesprataren. Reaktionstidsväggen skulle mäta besökarens reaktionstid genom att tryckknappar, med inbyggda dioder som slumpvis tänds, trycks ned i rätt ordning. Baklängesprataren skulle spela in besökarens tal och sedan spela upp det baklänges. Tanken var att besökaren skulle försöka prata baklänges och få det att låta rätt vid uppspelning. Arbetet gick ut på att bygga dessa demonstratorer och montera dem i Fiffiga huset. Reaktionstidsväggen styrdes med hjälp av en mikroprocessor ATMega16 från Atmel. Dess jobb var att läsa av knapptryckningar samt skicka information till dioder och display. Även baklängesprataren skulle styras med hjälp av mikroprocessorn ATMega16. En enkel mikrofonförstärkare samt filter till högtalarna skulle anslutas till processorn. Det inbyggda minnet skulle inte räcka till så ett extern minne behövde anslutas.Endast reaktionstidsväggen hann bli färdig inom projektets ramar eftersom all gammal elektronik som medföljde från Nobelmuseet var komplex, samt att många kortslutningar och avbrott gjorde felsökning till en tidskrävande procedur.

  • 64.
    Bonaccorsi, Manuele
    et al.
    The BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa, Italy.
    Fiorini, Laura
    The BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa, Italy.
    Cavallo, Filippo
    The BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa, Italy.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Dario, Paolo
    The BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa, Italy.
    A cloud robotics solution to improve social assistive robots for active and healthy aging2016In: International Journal of Social Robotics, ISSN 1875-4791, E-ISSN 1875-4805, Vol. 8, no 3, p. 393-408Article in journal (Refereed)
    Abstract [en]

    Technological innovation in robotics and ICT represents an effective solution to tackle the challenge of providing social sustainable care services for the ageing population. The recent introduction of cloud technologies is opening new opportunities for the provisioning of advanced robotic services based on the cooperation of a number of connected robots, smart environments and devices improved by the huge cloud computational and storage capability. In this context, this paper aims to investigate and assess the potentialities of a cloud robotic system for the provisioning of assistive services for the promotion of active and healthy ageing. The system comprised two different smart environments, located in Italy and Sweden, where a service robot is connected to a cloud platform for the provisioning of localization based services to the users. The cloud robotic services were tested in the two realistic environments to assess the general feasibility of the solution and demonstrate the ability to provide assistive location based services in a multiple environment framework. The results confirmed the validity of the solution but also suggested a deeper investigation on the dependability of the communication technologies adopted in such kind of systems.

  • 65.
    Bouguerra, Abdelbaki
    Örebro University, Department of Technology.
    A reactive approach for object finding in real world environments2006In: Intelligent Autonomous Systems 9 / [ed] Tamio Arai, Rolf Pfeifer, Tucker Balch, Hiroshi Yokoi, 2006, p. 391-398Conference paper (Other academic)
    Abstract [en]

    In this paper we propose an approach to handle requests of finding objects in real world environments by mobile robots. The proposed approach checks candidate objects based on the likelihood they constitute an answer to the requests in a reactive way. As a result, run-time perceived objects are handled “on the fly” without extra cost. We present the theoretical concepts of the proposed approach, and describe the experiments we run to validate it.

  • 66.
    Boustedt, Katarina
    Örebro University, Department of Technology.
    Flip chip for high frequency applications: materials aspects2007Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Flip chip has since decades been the primary choice for chip interconnect for high performance circuits. Over the last few years, interest from the microwave arena has increased, and at this point in time microwave flip chip is a possible option for volume production.

    This thesis is based on an extensive literature survey in combination with experiments done in collaboration with Ericsson, Flextronics in Linköping and Chalmers University of Technology in Gothenburg. The backbone of the literature survey was published as a chapter on high frequency interconnects in the reference book “Area Array Interconnection Handbook” (2002), edited by Karl Puttlitz and Paul A. Totta, who are known as the fathers of flip chip. This literature study has since then been expanded and the latest search was

    done in June 2007.

    Four groups of experiments are reported in this thesis. The fi rst experiments are on stud bumping thin film substrates for subsequent fl ip-chip bonding. The wire was 17-μm diameter Au1Pd and bumping was uniform and successful, after some initial equipment problems.

    The second is a set of tests on flip-chip bonding using gold stud bumps, gold tin solder-on-substrate, and plated gold pillars on alumina carriers. To evaluate the joining process using these different bumps, chips made of alumina

    with coplanar waveguide transmission lines were thermocompression bonded to the bumped carriers. Bonder parameters were assessed related to the different bump types and materials. The bonding results were analyzed using shear tests, transmissive x-ray and scanning electron microscopy on

    cross-sections.

    The third experiment lot contains early results on reliability of stud-bump flip chip of gallium arsenide microstrip chips. Since the sample availability was very low and the joining process still under development, the results are vague, although it was fruitful to establish adequate methods of analysis and test.

    The fourth set of experiments involved the same alumina on alumina assembly, and flip-chip underfill and its impact measured up to 70 GHz. Three different underfill materials were applied to the test vehicles described above. Before and after underfilling, the test vehicles were measured for S parameters and compared.

    This study concludes that for flip chip on gold pads, the preferred joining process is soldering, just as for silicon chips with aluminum or copper pads. Since solder bumping on gold pads is hard to come by, the second best choice is plated pillars, on carrier or chip, and thirdly, gold wire stud bumping.

    Underfill for microwave applications should not necessarily be dreaded to the extent that it is today. This study has proven that the matching of lines isnot affected and the changes in dips can be considered in the early phases of the design process for chip and carrier.

  • 67.
    Boustedt, Katarina
    et al.
    Örebro University, School of Science and Technology.
    Persson, Katrin
    IMEGO, Gothenburg, Sweden.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Flip chip as an enabler for MEMS packaging2002In: 52nd Electronic Components and Technology Conference, 2002. Proceedings., 2002, p. -128Conference paper (Refereed)
    Abstract [en]

    With the recent trends in microelectronics to move more and more towards incorporating MEMS (micro electro mechanical systems) structures, lowering the overall cost becomes vital. One major cost driver in today's MEMS is the packaging. Many of the MEMS structures require some level of low pressure for full quality operation, and some may even need vacuum to function properly. Different MEMS packaging strategies exist on the market and they can be divided into two different approaches. The first one protects the wafer temporarily during wafer scribing or dicing and the second one provides a permanent seal to the wafer through full wafer bonding before scribing and dicing. The latter, permanent methods allows for selecting very low cost packaging without hermeticity as a requirement, whereas in the temporary seal methods the seal is removed after dicing and the sensitive structures become unprotected again. Using flip chip for MEMS has the benefit of providing MEMS structures with a covering lid, the chip itself. A number of flip chip MEMS interconnection methods presented in literature are described.

  • 68.
    Boustedt, Katarina
    et al.
    Örebro University, School of Science and Technology.
    Persson, Katrin
    IMEGO, Gothenburg, Sweden.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Bohman, Sofie
    IMEGO, Gothenburg, Sweden.
    Wafer Bonding Technologies for MEMS Packaging2002In: Proceedings : the IMAPS Nordic Annual Conference : Stockholm, 2002, 29 September-2 October 2002., 2002, p. -127Conference paper (Other academic)
  • 69.
    Burgués, Javier
    et al.
    Institute for Bioengineering of Catalonia (IBEC),The Barcelona Institute of Science and Technology, Baldiri Reixac, Barcelona, Spain; Department of Electronics and Biomedical Engineering, Universitat de Barcelona, Barcelona, Spain.
    Hernandez Bennetts, Victor
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Marco, Santiago
    Institute for Bioengineering of Catalonia (IBEC),The Barcelona Institute of Science and Technology, Baldiri Reixac, Barcelona, Spain; Department of Electronics and Biomedical Engineering, Universitat de Barcelona, Barcelona, Spain.
    Smelling Nano Aerial Vehicle for Gas Source Localization and Mapping2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 3, article id 478Article in journal (Refereed)
    Abstract [en]

    This paper describes the development and validation of the currently smallest aerial platform with olfaction capabilities. The developed Smelling Nano Aerial Vehicle (SNAV) is based on a lightweight commercial nano-quadcopter (27 g) equipped with a custom gas sensing board that can host up to two in situ metal oxide semiconductor (MOX) gas sensors. Due to its small form-factor, the SNAV is not a hazard for humans, enabling its use in public areas or inside buildings. It can autonomously carry out gas sensing missions of hazardous environments inaccessible to terrestrial robots and bigger drones, for example searching for victims and hazardous gas leaks inside pockets that form within the wreckage of collapsed buildings in the aftermath of an earthquake or explosion. The first contribution of this work is assessing the impact of the nano-propellers on the MOX sensor signals at different distances to a gas source. A second contribution is adapting the ‘bout’ detection algorithm, proposed by Schmuker et al. (2016) to extract specific features from the derivative of the MOX sensor response, for real-time operation. The third and main contribution is the experimental validation of the SNAV for gas source localization (GSL) and mapping in a large indoor environment (160 m2) with a gas source placed in challenging positions for the drone, for example hidden in the ceiling of the room or inside a power outlet box. Two GSL strategies are compared, one based on the instantaneous gas sensor response and the other one based on the bout frequency. From the measurements collected (in motion) along a predefined sweeping path we built (in less than 3 min) a 3D map of the gas distribution and identified the most likely source location. Using the bout frequency yielded on average a higher localization accuracy than using the instantaneous gas sensor response (1.38 m versus 2.05 m error), however accurate tuning of an additional parameter (the noise threshold) is required in the former case. The main conclusion of this paper is that a nano-drone has the potential to perform gas sensing tasks in complex environments.

  • 70.
    Burgués, Javier
    et al.
    Department of Electronic and Biomedical Engineering, Universitat de Barcelona, Barcelona, Spain; Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain.
    Hernandez Bennetts, Victor
    Örebro University, School of Science and Technology.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Marco, Santiago
    Department of Electronic and Biomedical Engineering, Universitat de Barcelona, Barcelona, Spain; Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain.
    3D Gas Distribution with and without Artificial Airflow: An Experimental Study with a Grid of Metal Oxide Semiconductor Gas Sensors2018In: Proceedings, E-ISSN 2504-3900, Vol. 2, no 13, article id 911Article in journal (Refereed)
    Abstract [en]

    Gas distribution modelling can provide potentially life-saving information when assessing the hazards of gaseous emissions and for localization of explosives, toxic or flammable chemicals. In this work, we deployed a three-dimensional (3D) grid of metal oxide semiconductor (MOX) gas sensors deployed in an office room, which allows for novel insights about the complex patterns of indoor gas dispersal. 12 independent experiments were carried out to better understand dispersion patters of a single gas source placed at different locations of the room, including variations in height, release rate and air flow profiles. This dataset is denser and richer than what is currently available, i.e., 2D datasets in wind tunnels. We make it publicly available to enable the community to develop, validate, and compare new approaches related to gas sensing in complex environments.

  • 71.
    Canelhas, Daniel Ricão
    et al.
    Univrses AB, Strängnäs, Sweden.
    Stoyanov, Todor
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    A Survey of Voxel Interpolation Methods and an Evaluation of Their Impact on Volumetric Map-Based Visual Odometry2018In: Proceedings of the IEEE International Conference on Robotics and Automation (ICRA),, IEEE Computer Society, 2018, p. 6337-6343Conference paper (Refereed)
    Abstract [en]

    Voxel volumes are simple to implement and lend themselves to many of the tools and algorithms available for 2D images. However, the additional dimension of voxels may be costly to manage in memory when mapping large spaces at high resolutions. While lowering the resolution and using interpolation is common work-around, in the literature we often find that authors either use trilinear interpolation or nearest neighbors and rarely any of the intermediate options. This paper presents a survey of geometric interpolation methods for voxel-based map representations. In particular we study the truncated signed distance field (TSDF) and the impact of using fewer than 8 samples to perform interpolation within a depth-camera pose tracking and mapping scenario. We find that lowering the number of samples fetched to perform the interpolation results in performance similar to the commonly used trilinear interpolation method, but leads to higher framerates. We also report that lower bit-depth generally leads to performance degradation, though not as much as may be expected, with voxels containing as few as 3 bits sometimes resulting in adequate estimation of camera trajectories.

  • 72.
    Carletti, Cristina
    et al.
    Marche Polytechnic University Ancona, Ancona, Italy.
    Di Rocco, Maurizio
    Roma Tre University, Rome, Italy.
    Gasparri, Andrea
    Roma Tre University, Rome, Italy.
    Ulivi, Giovanni
    Roma Tre University, Rome, Italy.
    A distributed transferable belief model for collaborative topological map-building in multi-robot systems2010In: 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, 2010, p. 554-560Conference paper (Refereed)
    Abstract [en]

    In this paper the problem of multi-robot collaborative topological map-building is addressed. In this framework, a team of robots is supposed to move in an indoor office-like environment. Each robot, after building a local map by using infrared range-finders, achieves a topological representation of the environment by extracting the most significant features via the Hough transform and comparing them with a set of predefined environmental patterns. The local view of each robot which is significantly constrained by its limited sensing capabilities is then strengthened by a collaborative aggregation schema based on the Transferable Belief Model (TBM). In this way, a better representation of the environment is achieved by each robot with a minimal exchange of information. A preliminary experimental validation carried out by exploiting data collected from a self-made team of robots is proposed.

  • 73.
    Carlson, Jan
    et al.
    Department of Computer Science and Engineering, Mälardalen University, Västerås, Sweden.
    Lennvall, Tomas
    Department of Computer Science and Engineering, Mälardalen University, Västerås, Sweden.
    Fohler, Gerhard
    Department of Computer Science and Engineering, Mälardalen University, Västerås, Sweden.
    Enhancing time triggered scheduling with value based overload handling and task migration2003In: Sixth IEEE International Symposium on Object-Oriented Real-Time Distributed Computing, 2003: Proceedings, IEEE Computer Society, 2003, p. 121-128Conference paper (Refereed)
    Abstract [en]

    Time triggered methods provide deterministic behaviour suitable for critical real-time systems. The), perform less favourably, however if the arrival times of some activities are not known in advance, in particular if overload situations have to be anticipated. In many systems, the criticality of only a subset of activities justify the cost associated with the time triggered methods.

    In this paper we consider distributed systems where a subset of critical activities are handled in a time triggered fashion, via an offline schedule. At runtime, the arrival of aperiodic tasks may cause overload that demands to be handled in such a way that i) time triggered activities still meet all their original constraints, ii) execution of high-valued tasks are prioritised over tasks with lower value, iii) tasks can be quickly migrated to balance the overall system load.

    We give a precise formulation of overload detection and value based task rejection in the presence of offline scheduled tasks, and present a heuristic algorithm to handle overload. To benefit from the distributed setting, the overload handling includes an algorithm that integrates migration of rejected tasks with resource reclaiming and an acceptance test of newly arrived tasks.

    Simulation results underline the effectiveness of the presented approach.

  • 74.
    Carlsson, Johannes
    Örebro University, School of Science and Technology.
    Digital ljudkvalitetsoptimering för hörlurar.2011Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete har utförts hos Dirac Research AB i Uppsala. Dirac Research är en världsledande programvaruspecialist inom ljudoptimering, rumskorrigering och ljudfältssyntes.

    Dirac har nu velat utreda hur man på bästa sätt kan använda deras programvara Dirac Live för att förbättra ljudet hos hörlurar. I examensarbetet ingick en teoretisk del om örat, hörlurar, mätmetoder och hur en frekvenskurva bör se ut. Det ingick också att mäta impulssvaret för några olika hörlurar. Impulssvaret användes sedan till att förbättra ljudet hos hörlurarna genom att designa digitala filter som användes genom programvaran Dirac Live. När filterdesignen var klar utfördes ett lyssningstest för att få åsikter om hur andra upplevde filtrena.

    Mätningarna utfördes på Karolinska Institutet i Huddingen på ett KEMAR-huvud. Det är ett konsthuvud som ska efterlikna en människas huvud till form och storlek. Där mättes fyra earbuds (intra-concha), tre in-ear (insert), två omslutande (circum-aural) och ett par utanpåliggande (supra-aural) hörlurar upp. Med filterdesignen visade det sig att förbättringar upplevdes på de flesta av hörlurarna. Dock så kompenserades inte de omslutande- och utanpåliggande hörlurarna något. Dessa var endast tänkta att ha som referens.

    Det var en del skillnader mellan de olika hörlurarnas frekvenssvar. Det beror delvis på hörselgångens resonansfrekvens. När omslutande hörlurar mäts kan hörselgången ses som en kvartsvågsresonator medan den vid mätning av in-ear-hörlurar kan ses som halvvågsresonator. Även hörlurarnas konstruktion påverkar skillnaderna för de olika hörlurstyperna.

    Som målkurvor till hörlurarna användes bland annat högtalarmätningar i form av frifältsmätningar och diffusfältsmätningar utöver de hörlurar som användes som referens. Dock upplevdes en frekvensgång med en mjuk topp vid 3 kHz och i övrigt ganska rak frekvensgång som bäst. Vid lyssningstestet var det även den kurvan som fick flest röster hos tre av de fyra hörlurarna som användes vid lyssningstestet.

  • 75. Carpin, Stefano
    et al.
    Stoyanov, Todor
    Örebro University, School of Science and Technology.
    Nevatia, Yashodhan
    Lewis, M.
    Wang, J.
    Quantitative Assessments of USARSim Accuracy2006Conference paper (Refereed)
  • 76.
    Chakraborty, Subham
    et al.
    Innopolis University, Universitetskaya, Innopolis, Russia.
    Thapaliya, Ananga
    Innopolis University, Universitetskaya, Innopolis, Russia.
    Above the Clouds: A Brief Study2019In: Software Technology: Methods and Tools / [ed] Manuel MazzaraJean-Michel BruelBertrand MeyerAlexander Petrenko, Springer, 2019, Vol. 11771, p. 326-333Conference paper (Refereed)
    Abstract [en]

    Cloud Computing is a versatile technology that can support a broad-spectrum of applications. The low cost of cloud computing and its dynamic scaling renders it an innovation driver for small companies, particularly in the developing world. Cloud deployed enterprise resource planning (ERP), supply chain management applications (SCM), customer relationship management (CRM) applications, medical applications, business applications and mobile applications have potential to reach millions of users. In this paper, we explore the different concepts involved in cloud computing and we also examine clouds from technical aspects. We highlight some of the opportunities in cloud computing underlining the importance of clouds showing why that technology must succeed and we have provided additional cloud computing problems that businesses may need to address. Finally, we discuss some of the issues that this area should deal with.

  • 77.
    Charusta, Krzysztof
    et al.
    Örebro University, School of Science and Technology.
    Krug, Robert
    Örebro University, School of Science and Technology.
    Dimitrov, Dimitar
    Örebro University, School of Science and Technology.
    Iliev, Boyko
    Örebro University, School of Science and Technology.
    Independent contact regions based on a patch contact model2012In: 2012 IEEE International Conference on Robotics and Automation (ICRA), IEEE conference proceedings, 2012, p. 4162-4169Conference paper (Refereed)
    Abstract [en]

    The synthesis of multi-fingered grasps on nontrivial objects requires a realistic representation of the contact between the fingers of a robotic hand and an object. In this work, we use a patch contact model to approximate the contact between a rigid object and a deformable anthropomorphic finger. This contact model is utilized in the computation of Independent Contact Regions (ICRs) that have been proposed as a way to compensate for shortcomings in the finger positioning accuracy of robotic grasping devices. We extend the ICR algorithm to account for the patch contact model and show the benefits of this solution.

  • 78.
    Charusta, Krzysztof
    et al.
    Örebro University, School of Science and Technology.
    Krug, Robert
    Örebro University, School of Science and Technology.
    Stoyanov, Todor
    Örebro University, School of Science and Technology.
    Dimitrov, Dimitar
    Örebro University, School of Science and Technology.
    Iliev, Boyko
    Örebro University, School of Science and Technology.
    Generation of independent contact regions on objects reconstructed from noisy real-world range data2012In: 2012 IEEE International Conference on Robotics and Automation (ICRA), IEEE conference proceedings, 2012, p. 1338-1344Conference paper (Refereed)
    Abstract [en]

    The synthesis and evaluation of multi-fingered grasps on complex objects is a challenging problem that has received much attention in the robotics community. Although several promising approaches have been developed, applications to real-world systems are limited to simple objects or gripper configurations. The paradigm of Independent Contact Regions (ICRs) has been proposed as a way to increase the tolerance to grasp positioning errors. This concept is well established, though only on precise geometric object models. This work is concerned with the application of the ICR paradigm to models reconstructed from real-world range data. We propose a method for increasing the robustness of grasp synthesis on uncertain geometric models. The sensitivity of the ICR algorithm to noisy data is evaluated and a filtering approach is proposed to improve the quality of the final result.

  • 79.
    Chatzipetrou, Panagiota
    et al.
    Software Research Engineering Lab (SERL), Blekinge Institute of Technology, Karlskrona, Sweden.
    Alégroth, Emil
    Software Research Engineering Lab (SERL), Blekinge Institute of Technology, Karlskrona, Sweden.
    Papatheocharous, Efi
    RISE SICS AB, Lund, Sweden.
    Borg, Markus
    RISE SICS AB, Lund, Sweden.
    Gorschek, Tony
    Software Research Engineering Lab (SERL), Blekinge Institute of Technology, Karlskrona, Sweden.
    Wnuk, Krzysztof
    Software Research Engineering Lab (SERL), Blekinge Institute of Technology, Karlskrona, Sweden.
    Component selection in Software Engineering: Which attributes are the most important in the decision process?2018In: 44th Euromicro Conference on Software Engineering and Advanced Applications, SEAA 2018: Proceedings / [ed] Bures, T; Angelis, L, IEEE conference proceedings , 2018, p. 198-205Conference paper (Refereed)
    Abstract [en]

    Component-based software engineering is a common approach to develop and evolve contemporary software systems where different component sourcing options are available: 1)Software developed internally (in-house), 2)Software developed outsourced, 3)Commercial of the shelf software, and 4) Open Source Software.

    However, there is little available research on what attributes of a component are the most important ones when selecting new components. The object of the present study is to investigate what matters the most to industry practitioners during component selection. We conducted a cross-domain anonymous survey with industry practitioners involved in component selection. First, the practitioners selected the most important attributes from a list. Next, they prioritized their selection using the Hundred-Dollar ($100) test. We analyzed the results using Compositional Data Analysis. The descriptive results showed that Cost was clearly considered the most important attribute during the component selection. Other important attributes for the practitioners were: Support of the component, Longevity prediction, and Level of off-the-shelf fit to product. Next, an exploratory analysis was conducted based on the practitioners' inherent characteristics. Nonparametric tests and biplots were used. It seems that smaller organizations and more immature products focus on different attributes than bigger organizations and mature products which focus more on Cost.

  • 80.
    Cirillo, Marcello
    Örebro University, School of Science and Technology.
    Planning in inhabited environments: human-aware task planning and activity recognition2011In: Künstliche Intelligenz, ISSN 0933-1875, E-ISSN 1610-1987, Vol. 25, no 4, p. 355-358Article in journal (Refereed)
    Abstract [en]

    Our work addresses issues related to the cohabitation of service robots and people in unstructured environments. We propose new planning techniques to empower robot means-end reasoning with the capability of taking into account human intentions and preferences. We also address the problem of human activity recognition in instrumented environments. We employ a constraint-based approach to realize a continuous inference process to attach a meaning to sensor traces as detected by sensors distributed in the environment.

  • 81.
    Cirillo, Marcello
    et al.
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    Uras, Tansel
    Department of Computer Science, University of Southern California, Los Angeles, USA.
    Koenig, Sven
    Department of Computer Science, University of Southern California, Los Angeles, USA.
    Integrated Motion Planning and Coordination for Industrial Vehicles2014In: Proceedings of the 24th International Conference on Automated Planning and Scheduling, AAAI Press, 2014Conference paper (Refereed)
    Abstract [en]

    A growing interest in the industrial sector for autonomous ground vehicles has prompted significant investment in fleet management systems. Such systems need to accommodate on-line externally imposed temporal and spatial requirements, and to adhere to them even in the presence of contingencies. Moreover, a fleet management system should ensure correctness, i.e., refuse to commit to requirements that cannot be satisfied. We present an approach to obtain sets of alternative execution patterns (called trajectory envelopes) which provide these guarantees. The approach relies on a constraint-based representation shared among multiple solvers, each of which progressively refines trajectory envelopes following a least commitment principle.

  • 82.
    Cirillo, Marcello
    et al.
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Proactive assistance in ecologies of physically embedded intelligent systems: a constraint-based approach2011In: Handbook of research on ambient intelligence and smart environments: trends and perspectives / [ed] Nak-Young Chong, Fulvio Mastrogiovanni, IGI Global, 2011, p. 534-557Chapter in book (Refereed)
    Abstract [en]

    The main goal of this Chapter is to introduce SAM, an integrated architecture for concurrent activity recognition, planning and execution. SAM provides a general framework to define how an intelligent environment can assess contextual information from sensory data. The architecture builds upon a temporal reasoning framework operating in closed-loop between physical sensing and actuation components in a smart environments. The capabilities of the system as well as possible examples of its use are discussed in the context of the PEIS-Home, a smart environment integrated with robotic components.

  • 83.
    Cirillo, Marcello
    et al.
    Örebro University, School of Science and Technology.
    Uras, Tansel
    Department of Computer Science, University of Southern California, Los Angeles, USA.
    Koenig, Sven
    Department of Computer Science, University of Southern California, Los Angeles, USA.
    A lattice-based approach to multi-robot motion planning for non-holonomic vehicles2014In: Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems, 2014, p. 232-239Conference paper (Refereed)
    Abstract [en]

    Coordinating fleets of autonomous, non-holonomic vehicles is paramount to many industrial applications. While there exists solutions to efficiently calculate trajectories for individual vehicles, an effective methodology to coordinate their motions and to avoid deadlocks is still missing. Decoupled approaches, where motions are calculated independently for each vehicle and then centrally coordinated for execution, have the means to identify deadlocks, but not to solve all of them. We present a novel approach that overcomes this limitation and that can be used to complement the deficiencies of decoupled solutions with centralized coordination. Here, we formally define an extension of the framework of lattice-based motion planning to multi-robot systems and we validate it experimentally. Our approach can jointly plan for multiple vehicles and it generates kinematically feasible and deadlock-free motions.

  • 84.
    Coradeschi, Silvia
    et al.
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Kristoffersson, Annica
    Örebro University, School of Science and Technology.
    Cortellessa, Gabriella
    Consiglio Nazionale delle Ricerche (CNR), Rome, Italy; Istituto di Scienze e Tecnologie della Cognizione (ISTC-CNR), Rome, Italy.
    Severinson Eklundh, Kerstin
    KTH, Royal Institute of Technology, Stockholm, Sweden.
    Social robotic telepresence2011In: the 6th ACM/IEEE International Conference on Human-Robot Interaction (HRI 2011).HRI, ACM Digital Library , 2011, p. 5-6Conference paper (Refereed)
  • 85.
    Dandan, Kinan
    et al.
    Örebro University, School of Science and Technology.
    Ananiev, Anani
    Örebro University, School of Science and Technology.
    Ivan, Kalaykov
    Örebro University, School of Science and Technology.
    SIRO: the silos surface cleaning robot concept2013Conference paper (Refereed)
    Abstract [en]

    A concept of a suspended robot for surface cleaning in silos is presented in this paper. The main requirements and limitations resulting from the specific operational conditions are discussed. Due to the large dimension of the silo as a confined space, specific kinematics of the robot manipulator is proposed. The major problems in its design are highlighted and an approach to resolve them is proposed. The suggested concept is a reasonable compromise between the basic contradicting factors in the design: small entrance and large surface of the confined space, suspension and stabilization of the robot

  • 86.
    Daoutis, Marios
    et al.
    Örebro University, School of Science and Technology.
    Coradeschi, Silvia
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Towards concept anchoring for cognitive robots2012In: Intelligent Service Robotics, ISSN 1861-2784, Vol. 5, no 4, p. 213-228Article in journal (Refereed)
    Abstract [en]

    We present a model for anchoring categorical conceptual information which originates from physical perception and the web. The model is an extension of the anchoring framework which is used to create and maintain over time semantically grounded sensor information. Using the augmented anchoring framework that employs complex symbolic knowledge from a commonsense knowledge base, we attempt to ground and integrate symbolic and perceptual data that are available on the web. We introduce conceptual anchors which are representations of general, concrete conceptual terms. We show in an example scenario how conceptual anchors can be coherently integrated with perceptual anchors and commonsense information for the acquisition of novel concepts.

  • 87.
    Daoutis, Marios
    et al.
    Örebro University, School of Science and Technology.
    Mavridis, Nikolaos
    Towards a Model for Grounding Semantic Composition2014Conference paper (Refereed)
  • 88.
    Di Rocco, Maurizio
    Roma Tre University.
    Formation control through environment pattern recognition for a multi-robotarchitecture2009Conference paper (Refereed)
  • 89.
    Di Rocco, Maurizio
    et al.
    Örebro University, School of Science and Technology. Roma Tre University, Rome, Italy.
    La Gala, Francesco
    Marine Technology Research Institute (INSEAN), Rome, Italy.
    Ulivi, Giovanni
    Roma Tre University, Rome, Italy.
    Testing Multirobot Algorithms SAETTA: A Small and Cheap Mobile Unit2013In: IEEE robotics & automation magazine, ISSN 1070-9932, E-ISSN 1558-223X, Vol. 20, no 2, p. 52-62Article in journal (Other academic)
  • 90.
    Di Rocco, Maurizio
    et al.
    Roma Tre University, Rome, Italy.
    Pascucci, Federica
    Probabilistic localization in sensor networks using distributed Kalman filter2010In: 7th IFAC Symposium on Intelligent Autonomous Vehicles 2010, Lecce, Italy / [ed] Giovanni Indiveri, Antonio M. Pascoal, 2010Conference paper (Refereed)
    Abstract [en]

    In recent years sensor networks have interested fields such as environment monitoring, surveillance and other distributed applications for data elaboration. This interest has been based on the decentralized approach in treating the information. However it is still a challenge to manipulate such streams of data when the dimension of the net becomes large despite computational capabilities and consumption constraints. In most of applications, location awareness is fundamental to accomplish common tasks. In this paper a probabilistic approach to solve localization problem in wireless sensor networks is presented. The algorithm, based on the Kalman Filter, estimates the sensors' location by an adaptive behavior. The technique proposed allows a reduction of the computation burden respect to the traditional Kalman Filter showing, as explained in simulations and real world experiments, good performances.

  • 91.
    Di Rocco, Maurizio
    et al.
    Roma Tre University.
    Pascucci, Federica
    Roma Tre University.
    Sensor network localization using distributed extended Kalman filter2007Conference paper (Refereed)
  • 92.
    Di Rocco, Maurizio
    et al.
    Roma Tre University.
    Pascucci, Federica
    Roma Tre University.
    Perillo, David
    Roma Tre University.
    Consensus filter for sensor networks localization and tracking2007Conference paper (Refereed)
  • 93.
    Di Rocco, Maurizio
    et al.
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Sivakumar, Prasanna Kumar
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Configuration Planning with Multiple Dynamic Goals2013In: Designing intelligent robots: reintegrating AI II. Papers from the AAAI Spring Symposium, AAAI Press, 2013, p. 12-17Conference paper (Refereed)
    Abstract [en]

    We propose an approach to configuration planning for robotic systems in which plans are represented as constraint networks and planning is defined as search in the space of such networks. The approach supports reasoning about time, resources, and information dependencies between actions. In addition, the system can leverage the flexibility of such networks at execution time to support dynamic goal posting and re-planning.

  • 94.
    Di Rocco, Maurizio
    et al.
    Örebro University, School of Science and Technology.
    Reggente, Matteo
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Gas source localization in indoor environments using multiple inexpensive robots and stigmergy2011In: 2011 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE, 2011, p. 5007-5014Conference paper (Refereed)
    Abstract [en]

    Environmental monitoring is a rather new field in robotics. One of the main appealing tasks is gas mapping, i.e., the characterization of the chemical properties (concentration, dispersion, etc.) of the air within an environment. Current approaches rely on a robot using standard localization and mapping techniques to fuse gas measures with spatial features. These approaches require sophisticated sensors and/or high computational resources. We propose a minimalistic approach, in which one or multiple low-cost robots exploit the ability to store information in the environment, or “stigmergy”, to effectively compute an artificial potential leading toward the likely location of the gas source, as indicated by a highest gas concentration or fluctuation. The potential is computed and stored directly on an array of RFID tags buried under the floor. Our approach has been validated in extensive experiments performed on real robots in a domestic environment.

  • 95.
    Di Rocco, Maurizio
    et al.
    Roma Tre University, Rome, Italy.
    Ulivi, Giavanni
    An efficient implementation of a particle filter for localization using compass data2010In: 7th IFAC Symposium on Intelligent Autonomous Vehicles 2010, Lecce, Italy / [ed] Giovanni Indiveri, Antonio M. Pascoal, 2010Conference paper (Refereed)
    Abstract [en]

    This paper presents a localization algorithm for a small mobile platform. Taking advantage from modern technology, Saetta, a low cost mobile robot, has been built from scratch. Due to the limited processing capabilities, some ad hoc solutions have been used: the lack of processing resources has been compensated by an efficient implementation of the estimator and by the use of compass measures which ease the computational load. The results show how a careful design allows the implementation of sophisticated algorithms also on small platforms.

  • 96.
    Dimitrov, Dimitar N.
    et al.
    Örebro University, School of Science and Technology.
    Wieber, P. -B.
    Stasse, O.
    Ferreau, H. J.
    Diedam, H.
    An optimized linear model predictive control solver for online walking motion generation2009In: IEEE International Conference on Robotics and Automation (ICRA '09), IEEE conference proceedings, 2009, p. 1171-1176Conference paper (Other academic)
    Abstract [en]

    This article addresses the fast solution of a Quadratic Program underlying a Linear Model Predictive Control scheme that generates walking motions. We introduce an algorithm which is tailored to the particular requirements of this problem, and therefore able to solve it efficiently. Different aspects of the algorithm are examined, its computational complexity is presented, and a numerical comparison with an existing state of the art solver is made. The approach presented here, extends to other general problems in a straightforward way. © 2009 IEEE.

  • 97.
    Dimitrov, Dimitar
    et al.
    Örebro University, School of Science and Technology.
    Paolillo, Antonio
    Wieber, Pierre-Brice
    Walking motion generation with online foot position adaptation based on L_1- and L_\inf-norm penalty formulations2010In: IEEE International conference on Robotics and automation (ICRA), IEEE conference proceedings, 2010, p. 3523-3529Conference paper (Refereed)
    Abstract [en]

    The article presents an improved formulation of an existing model predictive control scheme used to generate online "stable" walking motions for a humanoid robot. We introduce: (i) a change of variable that simplifies the optimiza tion problem to be solved; (ii) a simply bounded formulation in the case when the positions of the feet are predetermined; (iii) a formulation allowing foot repositioning (when the system is perturbed) based on ℓ1- and ℓ-norm minimization; (iv) a formulation that accounts for (approximate) double support constraints when foot repositioning occurs.

  • 98.
    Dimitrov, Dimitar
    et al.
    Örebro University, School of Science and Technology.
    Sherikov, Alexander
    Örebro University, School of Science and Technology.
    Wieber, Pierre-Brice
    A sparse model predictive control formulation for walking motion generation2011In: IEEE/RSJ International conference on Intelligent robots and systems (IROS), IEEE, 2011, p. 2292-2299Conference paper (Refereed)
    Abstract [en]

    This article presents a comparison between dense and sparse model predictive control (MPC) formulations, in the context of walking motion generation for humanoid robots. The former formulation leads to smaller, the latter one to larger but more structured optimization problem. We put an accent on the sparse formulation and point out a number of advantages that it presents. In particular, motion generation with variable center of mass (CoM) height, as well as variable discretization of the preview window, come at a negligible additional computational cost. We present a sparse formulation that comprises a diagonal Hessian matrix and has only simple bounds (while still retaining the possibility to generate motions for an omnidirectional walk). Finally, we present the results from a customized code used to solve the underlying quadratic program (QP).

  • 99.
    Dimitrov, Dimitar
    et al.
    Örebro University, School of Science and Technology.
    Wieber, Pierre-Brice
    Stasse, Olivier
    Ferreau, Hans Joachim
    Diedam, Holger
    An optimized linear model predictive control solver2010In: Recent advances in optimization and its applications in engineering / [ed] Moritz Diehl, Francois Glineur, Elias Jarlebring, Wim Michiels, Heidelberg: Springer, 2010, 1, p. 309-318Chapter in book (Refereed)
  • 100.
    Dmytryshyn, Andrii
    et al.
    Dept. Computing Science, Umeå University, Umeå, Sweden.
    Johansson, Stefan
    Dept. Computing Science, Umeå University, Umeå, Sweden.
    Kågström, Bo
    Dept. Computing Science, Umeå University, Umeå, Sweden.
    Canonical structure transitions of system pencils2015Report (Other academic)
    Abstract [en]

    We investigate the changes under small perturbations of the canonical structure information for a system pencil (A B C D) − s (E 0 0 0), det(E) ≠ 0, associated with a (generalized) linear time-invariant state-space system. The equivalence class of the pencil is taken with respect to feedback-injection equivalence transformation. The results allow to track possible changes under small perturbations of important linear system characteristics.

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