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  • 151.
    Gao, Shang
    et al.
    School of Business Administration, Zhongnan University of Economics and Law, Wuhan, China.
    Krogstie, John
    Department of Computer and Information Science, Norwegian University of Science and Technology, Trondheim, Norway.
    Siau, Keng
    Department of Business and Information Technology, Missouri University of Science and Technology, Rolla MO, United States.
    Adoption of mobile information services: An empirical study2014In: International Journal of Mobile Information Systems, ISSN 1574-017X, E-ISSN 1875-905X, Vol. 10, no 2, p. 147-171Article in journal (Refereed)
    Abstract [en]

    This study investigates the adoption of mobile information services at a Norwegian university. By expanding the Technology Acceptance Model (TAM), a new research model, known as the mobile services acceptance model (MSAM), is proposed. Based on the research model, seven research hypotheses are presented. The proposed research model and research hypotheses were empirically tested using data collected from a survey of users of a mobile service, extended Mobile Student Information Systems (eMSIS), at a Norwegian university. The findings indicate that the fitness of the research model is good. Support was also found for the seven research hypotheses. Among the factors, the personal initiatives and characteristics has the strongest influence on the intention to use eMSIS.

  • 152.
    Gao, Shang
    et al.
    Department of Computer and Information Science, Norwegian University of Science and Technology, Trondheim, Norway.
    Krogstie, John
    Department of Computer and Information Science, Norwegian University of Science and Technology, Trondheim, Norway.
    Siau, Keng
    Department of Management, University of Nebraska, Lincoln NE, USA.
    Developing an instrument to measure the adoption of mobile services2011In: International Journal of Mobile Information Systems, ISSN 1574-017X, E-ISSN 1875-905X, Vol. 7, no 1, p. 45-67Article in journal (Refereed)
    Abstract [en]

    Currently, there is no standard instrument for measuring user adoption of mobile services. Based on the mobile service acceptance model, this paper reports on the development of a survey instrument designed to measure user perception on mobile services acceptance. A survey instrument was developed by using some existing scales from prior instruments and by creating additional items which might appear to fit the construct definitions. In addition, a pilot study was conducted by distributing the survey to 25 users of a mobile service called Mobile Student Information Systems. As a result, a survey instrument containing 22 items were retained. Furthermore, the results showed that the reliabilities of all the scales in the survey instrument were above the target acceptance level.

  • 153.
    Garipov, Emil
    et al.
    Technical University of Sofia, Bulgaria.
    Stoilkov, Teodor
    Technical University of Sofia, Bulgaria.
    Kalaykov, Ivan
    Örebro University, Department of Natural Sciences.
    Multiple regressive model adaptive control2008In: New developments in robotics automation and control / [ed] Aleksandar Lazinica, Rijeka, Croatia: InTech , 2008, p. 59-84Chapter in book (Refereed)
  • 154.
    Gasparri, Andrea
    et al.
    Roma Tre University, Rome, Italy.
    Fiorini, Flavio
    Logofive Srl, Turin, Italy.
    Di Rocco, Maurizio
    Roma Tre University, Rome, Italy.
    Panzieri, Stefano
    Roma Tre University, Rome, Italy.
    A networked transferable belief model approach for distributed data aggregation2012In: IEEE transactions on systems, man and cybernetics. Part B. Cybernetics, ISSN 1083-4419, E-ISSN 1941-0492, Vol. 42, no 2, p. 391-405Article in journal (Refereed)
    Abstract [en]

    This paper focuses on the extension of the transferable belief model (TBM) to a multiagent-distributed context where no central aggregation unit is available and the information can be exchanged only locally among agents. In this framework, agents are assumed to be independent reliable sources which collect data and collaborate to reach a common knowledge about an event of interest. Two different scenarios are considered: In the first one, agents are supposed to provide observations which do not change over time (static scenario), while in the second one agents are assumed to dynamically gather data over time (dynamic scenario). A protocol for distributed data aggregation, which is proved to converge to the basic belief assignment given by an equivalent centralized aggregation schema based on the TBM, is provided. Since multiagent systems represent an ideal abstraction of actual networks of mobile robots or sensor nodes, which are envisioned to perform the most various kind of tasks, we believe that the proposed protocol paves the way to the application of the TBM in important engineering fields such as multirobot systems or sensor networks, where the distributed collaboration among players is a critical and yet crucial aspect.

  • 155.
    Gholami Shahbandi, Saeed
    et al.
    Center for Applied Intelligent Systems Research, Halmstad University, Halmstad, Sweden.
    Magnusson, Martin
    Örebro University, School of Science and Technology.
    2D map alignment with region decomposition2019In: Autonomous Robots, ISSN 0929-5593, E-ISSN 1573-7527, Vol. 43, no 5, p. 1117-1136Article in journal (Refereed)
    Abstract [en]

    In many applications of autonomous mobile robots the following problem is encountered. Two maps of the same environment are available, one a prior map and the other a sensor map built by the robot. To benefit from all available information in both maps, the robot must find the correct alignment between the two maps. There exist many approaches to address this challenge, however, most of the previous methods rely on assumptions such as similar modalities of the maps, same scale, or existence of an initial guess for the alignment. In this work we propose a decomposition-based method for 2D spatial map alignment which does not rely on those assumptions. Our proposed method is validated and compared with other approaches, including generic data association approaches and map alignment algorithms. Real world examples of four different environments with thirty six sensor maps and four layout maps are used for this analysis. The maps, along with an implementation of the method, are made publicly available online.

  • 156.
    Gholami Shahbandi, Saeed
    et al.
    Center for Applied Intelligent Systems Research, Halmstad University, Halmstad, Sweden.
    Magnusson, Martin
    Örebro University, School of Science and Technology.
    Iagnemma, Karl
    Robotic Mobility Group, Massachusetts Institute of Technology, Cambridge MA, USA.
    Nonlinear Optimization of Multimodal Two-Dimensional Map Alignment With Application to Prior Knowledge Transfer2018In: IEEE Robotics and Automation Letters, E-ISSN 2377-3766, Vol. 3, no 3, p. 2040-2047Article in journal (Refereed)
    Abstract [en]

    We propose a method based on a nonlinear transformation for nonrigid alignment of maps of different modalities, exemplified with matching partial and deformed two-dimensional maps to layout maps. For two types of indoor environments, over a dataset of 40 maps, we have compared the method to state-of-the-art map matching and nonrigid image registration methods and demonstrate a success rate of 80.41% and a mean point-to-point alignment error of 1.78 m, compared to 31.9% and 10.7 m for the best alternative method. We also propose a fitness measure that can quite reliably detect bad alignments. Finally, we show a use case of transferring prior knowledge (labels/segmentation), demonstrating that map segmentation is more consistent when transferred from an aligned layout map than when operating directly on partial maps (95.97% vs. 81.56%).

    Download full text (pdf)
    Nonlinear Optimization of Multimodal 2D Map Alignment with Application to Prior Knowledge Transfer
  • 157.
    Giaretta, Alberto
    et al.
    Örebro University, School of Science and Technology.
    De Donno, Michele
    DTU Compute, Technical University of Denmark, Kongens Lyngby, Denmark.
    Dragoni, Nicola
    Örebro University, School of Science and Technology. DTU Compute, Technical University of Denmark, Kongens Lyngby, Denmark.
    Adding Salt to Pepper: A Structured Security Assessment over a Humanoid Robot2018In: Proceedings of the 13th International Conference on Availability, Reliability and Security, ACM , 2018, article id 22Conference paper (Refereed)
    Abstract [en]

    The rise of connectivity, digitalization, robotics, and artificial intelligence (AI) is rapidly changing our society and shaping its future development. During this technological and societal revolution, security has been persistently neglected, yet a hacked robot can act as an insider threat in organizations, industries, public spaces, and private homes. In this paper, we perform a structured security assessment of Pepper, a commercial humanoid robot. Our analysis, composed by an automated and a manual part, points out a relevant number of security flaws that can be used to take over and command the robot. Furthermore, we suggest how these issues could be fixed, thus, avoided in the future. The very final aim of this work is to push the rise of the security level of IoT products before they are sold on the public market.

  • 158.
    Giaretta, Alberto
    et al.
    Örebro University, School of Science and Technology.
    Dragoni, Nicola
    Örebro University, School of Science and Technology. DTU Compute, Technical University of Denmark, Lyngby, Denmark.
    Massacci, Fabio
    Department of Information Science and Engineering, University of Trento, Trento, Italy.
    IoT Security Configurability with Security-by-Contract2019In: Sensors, E-ISSN 1424-8220, Vol. 19, no 19, article id E4121Article in journal (Refereed)
    Abstract [en]

    Cybersecurity is one of the biggest challenges in the Internet of Things (IoT) domain, as well as one of its most embarrassing failures. As a matter of fact, nowadays IoT devices still exhibit various shortcomings. For example, they lack secure default configurations and sufficient security configurability. They also lack rich behavioural descriptions, failing to list provided and required services. To answer this problem, we envision a future where IoT devices carry behavioural contracts and Fog nodes store network policies. One requirement is that contract consistency must be easy to prove. Moreover, contracts must be easy to verify against network policies. In this paper, we propose to combine the security-by-contract (S × C) paradigm with Fog computing to secure IoT devices. Following our previous work, first we formally define the pillars of our proposal. Then, by means of a running case study, we show that we can model communication flows and prevent information leaks. Last, we show that our contribution enables a holistic approach to IoT security, and that it can also prevent unexpected chains of events.

  • 159.
    Giaretta, Alberto
    et al.
    Örebro University, School of Science and Technology.
    Dragoni, Nicola
    DTU Compute, Technical University of Denmark, Kongens Lyngby, Denmark.
    Massacci, Fabio
    Department of Information Sciences and Engineering, University of Trento, Italy; Vrije Universiteit Amsterdam, Netherlands.
    S×C4IoT: A Security-by-contract Framework for Dynamic Evolving IoT Devices2022In: ACM transactions on sensor networks, ISSN 1550-4867, E-ISSN 1550-4859, Vol. 18, no 1, article id 12Article in journal (Refereed)
    Abstract [en]

    The Internet of Things (IoT) revolutionised the way devices, and human beings, cooperate and interact. The interconnectivity and mobility brought by IoT devices led to extremely variable networks, as well as unpredictable information flows. In turn, security proved to be a serious issue for the IoT, far more serious than it has been in the past for other technologies. We claim that IoT devices need detailed descriptions of their behaviour to achieve secure default configurations, sufficient security configurability, and self-configurability. In this article, we propose S×C4IoT, a framework that addresses these issues by combining two paradigms: Security by Contract (S×C) and Fog computing. First, we summarise the necessary background such as the basic S×C definitions. Then, we describe how devices interact within S×C4IoT and how our framework manages the dynamic evolution that naturally result from IoT devices life-cycles. Furthermore, we show that S×C4IoT can allow legacy S×C-noncompliant devices to participate with an S×C network, we illustrate two different integration approaches, and we show how they fit into S×C4IoT. Last, we implement the framework as a proof-of-concept. We show the feasibility of S×C4IoT and we run different experiments to evaluate its impact in terms of communication and storage space overhead.

    Download full text (pdf)
    S×C4IoT: A Security-by-contract Framework for Dynamic Evolving IoT Devices
  • 160.
    Gidlund, Mikael
    et al.
    Institutionen för informationsteknologi och medier, Mittuniversitetet, Västerås, sweden.
    Lennvall, Tomas
    Örebro University, School of Science and Technology. ABB Corporate Research, Västerås, Sweden.
    Neander, Jonas
    ABB Corporate Research, Västerås, Sweden.
    An energy efficient method for communication between a wireless sensor network and an industrial control system2011Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    The invention is a method for communication between a wireless device node in a wireless sensor network (WSN) and control apparatus or control processes of an industrial control system (ICS). The wireless network includes a plurality of device nodes and at least one gateway (GW). The method comprises receiving at a gateway an aggregated data packet (ADP) for a final address in the ICS. The gateway processes the data packet, detects that it is an aggregated data packet and reconstructs the original data packets contained therein. The gateway then sends each of the original data packets as standard data packets to the intended final address in the ICS. In other aspects of the invention a method, system and a computer program for carrying out the method are described.

  • 161.
    Gidlund, Mikael
    et al.
    Mid Sweden University, Västerås, Sweden.
    Lennvall, Tomas
    RISE SICS, Västerås, Sweden.
    Åkerberg, Johan
    ABB AB Corporate Research, Västerås, Sweden.
    Will 5G become yet another wireless technology for industrial automation?2017In: 2017 IEEE International Conference on Industrial Technology (ICIT): Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1319-1324Conference paper (Refereed)
    Abstract [en]

    With the growing interest in adoption of wireless technologies in industrial automation and the continuous search for new revenue streams new players are entering the arena in order to make their business grow further. One of the emerging wireless technologies aiming to support industrial automation applications is 5G, targeting anything from extreme throughput (> 10 Gbit/s) to extreme low latency (≤ 1 ms) to ultra high reliability (≥ 99.999%). In this article we intend to discuss the potential and challenges of adopting 5G in real industrial environments and give a more balanced picture compared to previous articles mainly written by telecom researchers and vendors as a way to promote their technology. Specifically, this article will discuss and provide some real industrial requirements, describe the main technical features of 5G and try to assess what applications it will support that are not by already supported by existing technologies. In the end, the success of 5G will depend on appealing business models and scalability, i.e., whether or not the same equipment can be deployed worldwide without any changes and spectrum rules, and the migration paths beyond 5G for reasonable business risks.

  • 162.
    Grantner, Janos L.
    et al.
    Western Michigan University, Dept. of Electrical and Computer Engineering, USA.
    Fodor, George. A.
    ABB Automation Products AB, Västerås, Sweden; Western Michigan University, Dept. of Electrical and Computer Engineering, USA.
    Driankov, Dimiter
    Department of Information and Computer Science, University of Linköping, Linköping, Sweden.
    The virtual fuzzy state machine approach: a domain-independent fault detection and recovery method for object-based control systems1999In: Proceedings of the 18th International Conference of the North American  Fuzzy Information Processing Society (NAFIPS), IEEE conference proceedings, 1999, p. 158-162Conference paper (Refereed)
    Abstract [en]

    The current trend of using object based design for real time control systems has the implication that traditional state based fault detection and recovery methods cannot be used directly. This problem is even more difficult for domain independent fault detection and recovery since most such methods are based on a formal analysis of the global state set. The paper presents a domain independent fault isolation, detection and recovery method for object based control systems based on constraints of the object architecture. Variations of the control behavior from normal cases are detected using a fuzzy state machine approach

  • 163.
    Grantner, J.L.
    et al.
    Western Michigan University, Kalamazoo, USA.
    Fodor, George
    George Fodor, Al3B Industrial Systems AB, ISY/AMC, Västerås.
    Driankov, Dimiter
    University of Linköping, Linköping.
    Hybrid fuzzy-Boolean automata for ontological controllers1998In: The 1998 IEEE International Conference on Fuzzy Systems Proceedings: IEEE World Congress on Computational Intelligence  (Volume:1), New York, USA: IEEE conference proceedings, 1998, p. 400-404Conference paper (Refereed)
    Abstract [en]

    This paper introduces a hybrid fuzzy-Boolean finite state machine (HFB FSM) model for ontological control. Ontological control is a novel type supervisory control that deals with the problems of error detection and recovery in complex control systems. The HFB FSM is used as a specification method for the problem of recovery when an autonomous control system encounters unexpected changes in its environment. The method allows a controller B (the ontological controller) to trigger a recovery operation on controller A when B has the recovery specification of A. The approach has important potential applications in industry

  • 164.
    Grosinger, Jasmin
    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.
    Making Robots Proactive through Equilibrium Maintenance2016In: 25th International Joint Conference on Artificial Intelligence, 2016Conference paper (Refereed)
  • 165.
    Gupta, Puneet Kumar
    et al.
    Independent Accessible Media Professional, Meerut, India.
    Mathew Martin, Poothullil John
    Department of Outreach & Extension Services, Ali Yavar Jung National Institute for the Hearing Handicapped, Mumbai, India.
    Comprehension of basic mathematics among children with hearing impairment using multimedia in accesible and non-accesible format a comparative study2013In: 2013 IEEE 63rd Annual Conference International Council for Educational Media (ICEM), IEEE conference proceedings, 2013, p. 1-11Conference paper (Refereed)
    Abstract [en]

    Teaching mathematics has been a complex issue for educators as well as learners. Same is the condition for the hearing impaired learners. Multimedia can be a big facilitator in order to render simpler and effective learning methods in the field of teaching mathematics to the hearing impaired students. The guidelines of United Nations Convention of Rights of Persons with Disabilities (UNCRPD, 2007), makes provision for creation of information in accessible format.

    However there are no research studies to establish that teaching mathematics through the accessible format of multimedia would increase comprehension levels in children with hearing impairment. According to Mary Ellen Foster (2003) in her study on visual comprehension found that ‘Intuitively, one way of determining the usefulness of any presentation of data is by measuring the ease with which tasks involving that data can be performed using that presentation’.

    It may be noted that children with hearing impairment use visual techniques in their thought process, therefore accessible format of multimedia will enhance their comprehension levels. Accessible format includes techniques such as captioning, sign language and audio Description.

    This can be very helpful in processing information by hearing impaired children. The study investigated the effects of multimedia in accessible format, through the use of captioning and Indian sign language (ISL), on hearing impaired children. Hearing impaired viewers watched twice, the short multimedia with and without accessibility formats respectively. Their reactions were recorded on a questionnaire developed for the purpose of the study.

    Forty nine students participated in this study from two deaf schools of Mumbai,India. Analysis of the data showed that there was difference in the effects of accessible and non accessible formats of on the Hearing Impaired viewers.

    The study also showed that accessible formats increase the comprehension of the subject of the multimedia and use of ISL and captioning helped hearing impaired students to understand concepts better. The hearing impaired persons correlated watching the ISL interpreter with understanding the concept of the topic of multimedia. Placement of the ISL interpreter in the screen was also covered under the study.

  • 166.
    Gustafsson, Erik
    Örebro University, School of Science and Technology.
    Vibratorbaserade hjälpmedel för personer med funktionshinder: Vibrator based Aids for people with Disabilities2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Over time, research has been made for communication with people with disabilities at Örebro University and in the University Hospital of Örebro. The research has been cooperated with the research network NovaMedTech. Mainly, this research has been directed to people who are deaf-blind. Communication with those persons is possible with vibrators in our current situation. Unfortunately, these vibrators don’t meet the requirements and my primary role in the continuation of this research is to find or construct a vibrator that meets those requirements.

    I used the vibrator that today’s research is built on as a benchmark. I started to examine the market of small vibrators that could meet the requirements. I needed a vibrator which could provide a wider frequency range and was linear. Most vibrators manufactured today are designed to attract attention, not to transfer information. This means that they have a high stimulus at a certain frequency. With that in mind I decided to construct a vibrator to get a better idea what restrictions there are and what difficulties I would encounter.

    My measurements show that it should be possible to design a vibrator that is sufficiently strong and has a frequency range that is wide enough to be used as communication tool for deaf-blind. If the vibrator can’t be linear is it possible to solve that problem with a control circuit that compensates its peaks and valleys and also compensates for nonlinearity in skin sensation. You can compare it with a speaker systems equalizer.

  • 167.
    Gustafsson, Thomas
    Örebro University, School of Science and Technology.
    Modernisering av testutrustning2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report describes the work to modernize a test equipmentt for a missile system. The new test equipment would be upgraded to use a USB interfaces instead of RS232 interface for communication between the computer and the rest of the hardware. The work begins with the specification and ends with a working product. In that included a brief explanation of the USB interface and its differences from the RS232 interface, an investigation to find the best solution for implementing USB communication with the equipment and construction of electronics to control signals and power supplies to the missile system.

    Download full text (pdf)
    fulltext
  • 168.
    Güler, Püren
    et al.
    Robotics, Perception and Learning Lab, School of Computer Science and Communication, KTH Royal Institute of Technology, Stockholm, Sweden.
    Pieropan, Alessandro
    KTH Royal Institute of Technology, Stockholm, Sweden; Ishikawa Watanabe Laboratory, University of Tokyo, Tokyo, Japan.
    Ishikawa, Masatoshi
    Ishikawa Watanabe Laboratory, University of Tokyo, Tokyo, Japan.
    Kragic, Danica
    Ishikawa Watanabe Laboratory, University of Tokyo, Tokyo, Japan.
    Estimating deformability of objects using meshless shape matching2017In: 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 5941-5948Conference paper (Refereed)
    Abstract [en]

    Humans interact with deformable objects on a daily basis but this still represents a challenge for robots. To enable manipulation of and interaction with deformable objects, robots need to be able to extract and learn the deformability of objects both prior to and during the interaction. Physics-based models are commonly used to predict the physical properties of deformable objects and simulate their deformation accurately. The most popular simulation techniques are force-based models that need force measurements. In this paper, we explore the applicability of a geometry-based simulation method called meshless shape matching (MSM) for estimating the deformability of objects. The main advantages of MSM are its controllability and computational efficiency that make it popular in computer graphics to simulate complex interactions of multiple objects at the same time. Additionally, a useful feature of the MSM that differentiates it from other physics-based simulation is to be independent of force measurements that may not be available to a robotic framework lacking force/torque sensors. In this work, we design a method to estimate deformability based on certain properties, such as volume conversation. Using the finite element method (FEM) we create the ground truth deformability for various settings to evaluate our method. The experimental evaluation shows that our approach is able to accurately identify the deformability of testing objects, supporting the value of MSM for robotic applications. 

  • 169. Günther, Martin
    et al.
    Hertzberg, Joachim
    Mansouri, Masoumeh
    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.
    Hybrid reasoning in perception: a case study2012In: IFAC-PapersOnLine, E-ISSN 2405-8963, Vol. 45, no 22, p. 90-95Article in journal (Refereed)
    Abstract [en]

    Robots operating in a complex human-inhabited environment need to represent and reason about different kinds of knowledge, including ontological, spatial, causal, temporal and resource knowledge. Often, these reasoning tasks are not mutually independent, but need to be integrated with each other. Integrated reasoning is especially important when dealing with knowledge derived from perception, which may be intrinsically incomplete or ambiguous. For instance, the non-observable property that a dish has been used and should therefore be washed can be inferred from the observable properties that it was full before and that it is empty now. In this paper, we present a hybrid reasoning framework which allows to easily integrate different kinds of reasoners. We demonstrate the suitability of our approach by integrating two kinds of reasoners, for ontological reasoning and for temporal reasoning, and using them to recognize temporally and ontologically defined object properties in point cloud data captured using an RGB-D camera.

  • 170.
    Hang, Kaiyu
    et al.
    Department of Mechanical Engineering and Material Science, Yale University, New Haven, CT, USA.
    Lyu, Ximin
    Hong Kong University of Science and Technology, Hong Kong, China.
    Song, Haoran
    Hong Kong University of Science and Technology, Hong Kong, China.
    Stork, Johannes Andreas
    Örebro University, School of Science and Technology. RPL, KTH Royal Institute of Technology, Stockholm, Sweden.
    Dollar, Aaron
    Department of Mechanical Engineering and Material Science, Yale University, New Haven, CT, USA.
    Kragic, Danica
    RPL, KTH Royal Institute of Technology, Stockholm, Sweden.
    Zhang, Fu
    The University of Hong Kong, Hong Kong, China.
    Perching and resting: A paradigm for UAV maneuvering with modularized landing gears2019In: Science Robotics, E-ISSN 2470-9476, Vol. 4, no 28, article id eaau6637Article in journal (Refereed)
    Abstract [en]

    Perching helps small unmanned aerial vehicles (UAVs) extend their time of operation by saving battery power. However, most strategies for UAV perching require complex maneuvering and rely on specific structures, such as rough walls for attaching or tree branches for grasping. Many strategies to perching neglect the UAV’s mission such that saving battery power interrupts the mission. We suggest enabling UAVs with the capability of making and stabilizing contacts with the environment, which will allow the UAV to consume less energy while retaining its altitude, in addition to the perching capability that has been proposed before. This new capability is termed “resting.” For this, we propose a modularized and actuated landing gear framework that allows stabilizing the UAV on a wide range of different structures by perching and resting. Modularization allows our framework to adapt to specific structures for resting through rapid prototyping with additive manufacturing. Actuation allows switching between different modes of perching and resting during flight and additionally enables perching by grasping. Our results show that this framework can be used to perform UAV perching and resting on a set of common structures, such as street lights and edges or corners of buildings. We show that the design is effective in reducing power consumption, promotes increased pose stability, and preserves large vision ranges while perching or resting at heights. In addition, we discuss the potential applications facilitated by our design, as well as the potential issues to be addressed for deployment in practice.

  • 171.
    Hassanzadeh, Rahman
    Örebro University, School of Science and Technology.
    Design och tillverkning av universell förstärkarmodul för trådtöjningsgivare2006Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The degree project assigned to me was to build a universal amplifier module for a strain gauge that could be used in 3 different states ie. quarter, half or full wheatstone bridge. The printed circuit card to be built for a company shall fulfil many needs and it is intended for industrial purposes.

    The most important is measuring the force on an object. This is accomplished with the help of a wheatstone bridge since voltage is directly proportional to resistance and furthermore resistance is proportional to force. This means that a change in resistance results in an increment or decrement of voltage. The important factor in this module is that it should register the least possible change in resistance so that a value gets recorded in the bridge. The reasons for using quarter, half or full bridge are explained later in the report.

    Measurement voltage for the module is +15 and -15 volts. The module should not give out a signal because of temp drift or imbalance of the object in measure at the point of zero balancing it. To attain this goal, I used:

     A microprocessor (ATmega 16) that has a built-in A/D converter.

     A D/A converter of 10 bits.

    In long distance measurements, the idea of monitoring current instead of voltage sounded better. This is because current remains the same along the line(wire) whereas voltage subsides the longer the wire. Calculation of voltage when resistance and current are given is pretty simple.

    The construction was partly done with the help of the program Multisim while the printed circuit card was manufactured with the help of Ultiboard.

    The result was a complete card with components mounted and constructed according to the company’s demands and specifications.

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    Design och tillverkning av universell förstärkarmodul för trådtöjningsgivare
  • 172.
    Hassanzadeh, Rahman
    Örebro University, School of Science and Technology.
    UTVECKLING AV PROCESSORPLATTFORM2007Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abstract

     

    The purpose of this project is to develop a modular processor card which is intended to work as a platform for Kitron Development Karlskoga. The modular processor card is meant to be used as a control system in development projects, mainly in medical and industrial products. The processor card will consist of a central unit with the basic functions for a control system. Furthermore there will be complete modules with machine commodity and programming, to pick exactly the necessary functions for a specific application.

     

    With consideration to the specification of the development and the main unit, I chose an adequate microprocessor (AT90CAN32) as core and interface circuits to stated border areas.

     

    The construction is first completed in the program MultiSim and then remade in the program OrCAD Capture. The programming language C was used in the software model. Then a layout was created in the program Ultiboard.

     

    The project has resulted in the manufacture of a pattern card that can manage I/O units, such as D/A-converter, keyboard, display and serial port RS-232. The purpose was that the units should communicate with the processor. The application decides what the main unit is used for.

     

    The D/A-converter was governed through SPI commands and the result was shown on an instrument (voltage). With the keyboard I was able to write digits to the processor and the result was shown on the display. The keyboard was used to send digits to the processor and was then sent through RS-232 to the PC. In the PC, a terminal program was used to receive digits.

     

    A general platform has been developed through this project, where you can choose which functions you wish to use (see the building block in figure no.1).

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    FULLTEXT03
  • 173.
    Haustein, J. A.
    et al.
    KTH Royal Institute of Technology, Division of Robotics, Perception and Learning (RPL), CAS, CSC, Stockholm, Sweden.
    Hang, K.
    Yale University, Department of Mechanical Engineering and Material Science, New Haven, United States.
    Stork, Johannes Andreas
    Örebro University, School of Science and Technology.
    Kragic, D.
    KTH Royal Institute of Technology, Division of Robotics, Perception and Learning (RPL), CAS, CSC, Stockholm, Sweden.
    Object Placement Planning and optimization for Robot Manipulators2019In: IEEE International Conference on Intelligent Robots and Systems, Institute of Electrical and Electronics Engineers (IEEE), 2019, p. 7417-7424Conference paper (Refereed)
    Abstract [en]

    We address the problem of planning the placement of a rigid object with a dual-arm robot in a cluttered environment. In this task, we need to locate a collision-free pose for the object that a) facilitates the stable placement of the object, b) is reachable by the robot and c) optimizes a user-given placement objective. In addition, we need to select which robot arm to perform the placement with. To solve this task, we propose an anytime algorithm that integrates sampling-based motion planning with a novel hierarchical search for suitable placement poses. Our algorithm incrementally produces approach motions to stable placement poses, reaching placements with better objective as runtime progresses. We evaluate our approach for two different placement objectives, and observe its effectiveness even in challenging scenarios.

  • 174.
    Herdenstam, Anders P. F.
    et al.
    Örebro University, School of Hospitality, Culinary Arts & Meal Science.
    Kurtser, Polina
    Örebro University, School of Science and Technology.
    Swahn, Johan
    Örebro University, School of Hospitality, Culinary Arts & Meal Science.
    Arunachalam, Ajay
    Örebro University, School of Science and Technology.
    Edberg, Karl-Magnus
    Örebro University, School of Hospitality, Culinary Arts & Meal Science.
    Nature versus machine: Sensory evaluation of robot-cultivated basil affected by mechanically induced stress2022Conference paper (Other academic)
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    Nature versus machine: Sensory evaluation of robot-cultivated basil affected by mechanically induced stress
  • 175. Herdt, Andrei
    et al.
    Diedam, Holger
    Wieber, Pierre-Brice
    Dimitrov, Dimitar
    Örebro University, School of Science and Technology.
    Mombaur, Katja
    Diehl, Moritz
    Online walking motion generation with automatic footstep placement2010In: Advanced Robotics, ISSN 0169-1864, E-ISSN 1568-5535, Vol. 24, no 5-6, p. 719-737Article in journal (Refereed)
    Abstract [en]

    The goal of this paper is to demonstrate the capacity of model predictive control (MPC) to generate stable walking motions without the use of predefined footsteps. Building up on well-known MPC schemes for walking motion generation, we show that a minimal modification of these schemes allows designing an online walking motion generator that can track a given reference speed of the robot and decide automatically the footstep placement. Simulation results are proposed on the HRP-2 humanoid robot, showing a significant improvement over previous approaches.

  • 176.
    Hernandez Bennetts, Victor
    et al.
    Örebro University, School of Science and Technology.
    Kamarudin, Kamarulzaman
    Center of Excellence for Advanced Sensor Technology, School of Mechatronics Engineering, Universiti Malaysia Perlis, Arau Perlis, Malaysia.
    Wiedemann, Thomas
    Institute of Communications and Navigation, German Aerospace Center, Oberpfaffenhofen, Germany.
    Kucner, Tomasz Piotr
    Örebro University, School of Science and Technology.
    Somisetty, Sai Lokesh
    Department of Mechatronics, Sastra University, Thanjavur, India.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Multi-Domain Airflow Modeling and Ventilation Characterization Using Mobile Robots, Stationary Sensors and Machine Learning2019In: Sensors, E-ISSN 1424-8220, Vol. 19, no 5, article id E1119Article in journal (Refereed)
    Abstract [en]

    Ventilation systems are critically important components of many public buildings and workspaces. Proper ventilation is often crucial for preventing accidents, such as explosions in mines and avoiding health issues, for example, through long-term exposure to harmful respirable matter. Validation and maintenance of ventilation systems is thus of key interest for plant operators and authorities. However, methods for ventilation characterization, which allow us to monitor whether the ventilation system in place works as desired, hardly exist. This article addresses the critical challenge of ventilation characterization-measuring and modelling air flow at micro-scales-that is, creating a high-resolution model of wind speed and direction from airflow measurements. Models of the near-surface micro-scale flow fields are not only useful for ventilation characterization, but they also provide critical information for planning energy-efficient paths for aerial robots and many applications in mobile robot olfaction. In this article we propose a heterogeneous measurement system composed of static, continuously sampling sensing nodes, complemented by localized measurements, collected during occasional sensing missions with a mobile robot. We introduce a novel, data-driven, multi-domain airflow modelling algorithm that estimates (1) fields of posterior distributions over wind direction and speed ("ventilation maps", spatial domain); (2) sets of ventilation calendars that capture the evolution of important airflow characteristics at measurement positions (temporal domain); and (3) a frequency domain analysis that can reveal periodic changes of airflow in the environment. The ventilation map and the ventilation calendars make use of an improved estimation pipeline that incorporates a wind sensor model and a transition model to better filter out sporadic, noisy airflow changes. These sudden changes may originate from turbulence or irregular activity in the surveyed environment and can, therefore, disturb modelling of the relevant airflow patterns. We tested the proposed multi-domain airflow modelling approach with simulated data and with experiments in a semi-controlled environment and present results that verify the accuracy of our approach and its sensitivity to different turbulence levels and other disturbances. Finally, we deployed the proposed system in two different real-world industrial environments (foundry halls) with different ventilation regimes for three weeks during full operation. Since airflow ground truth cannot be obtained, we present a qualitative discussion of the generated airflow models with plant operators, who concluded that the computed models accurately depicted the expected airflow patterns and are useful to understand how pollutants spread in the work environment. This analysis may then provide the basis for decisions about corrective actions to avoid long-term exposure of workers to harmful respirable matter.

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    Multi-Domain Airflow Modeling and Ventilation Characterization Using Mobile Robots, Stationary Sensors and Machine Learning
  • 177.
    Hernandez Bennetts, Victor
    et al.
    Örebro University, School of Science and Technology.
    Kucner, Tomasz Piotr
    Örebro University, School of Science and Technology.
    Schaffernicht, Erik
    Örebro University, School of Science and Technology.
    Neumann, Patrick P.
    Bundesanstalt für Materialforschung und -prüfung, Berlin, Germany.
    Fan, Han
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Probabilistic Air Flow Modelling Using Turbulent and Laminar Characteristics for Ground and Aerial Robots2017In: IEEE Robotics and Automation Letters, E-ISSN 2377-3766, Vol. 2, no 2, p. 1117-1123Article in journal (Refereed)
    Abstract [en]

    For mobile robots that operate in complex, uncontrolled environments, estimating air flow models can be of great importance. Aerial robots use air flow models to plan optimal navigation paths and to avoid turbulence-ridden areas. Search and rescue platforms use air flow models to infer the location of gas leaks. Environmental monitoring robots enrich pollution distribution maps by integrating the information conveyed by an air flow model. In this paper, we present an air flow modelling<?brk?> algorithm that uses wind data collected at a sparse number of locations to estimate joint probability distributions over wind speed and direction at given query locations. The algorithm uses a novel extrapolation approach that models the air flow as a linear combination of laminar and turbulent components. We evaluated the prediction capabilities of our algorithm with data collected with an aerial robot during several exploration runs. The results show that our algorithm has a high degree of stability with respect to parameter selection while outperforming conventional extrapolation approaches. In addition, we applied our proposed approach in an industrial application, where the characterization of a ventilation system is supported by a ground mobile robot. We compared multiple air flow maps recorded over several months by estimating stability maps using the Kullback&ndash;Leibler divergence between the distributions. The results show that, despite local differences, similar air flow patterns prevail over time. Moreover, we corroborated the validity of our results with knowledge from human experts.

  • 178.
    Hernandez Bennetts, Victor
    et al.
    Örebro University, School of Science and Technology.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Khaliq, Ali Abdul
    Örebro University, School of Science and Technology.
    Pomareda Sese, Victor
    Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain.
    Trincavelli, Marco
    Örebro University, Örebro, Sweden..
    Gasbot: A Mobile Robotic Platform for Methane Leak Detection and Emission Monitoring2012In: Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Workshop on Robotics for Environmental Monitoring (WREM), Vilamoura, Portugal, October 7-12, 2012, 2012Conference paper (Refereed)
    Abstract [en]

    Due to its environmental, economical and safety implications, methane leak detection is a crucial task to address in the biogas production industry. In this paper, we introduce Gasbot, a robotic platform that aims to automatize methane emission monitoring in landfills and biogas production sites. The distinctive characteristic of the Gasbot platform is the use of a Tunable Laser Absorption Spectroscopy (TDLAS) sensor, along with a novel gas distribution algorithm to generate methane concentration maps of indoor and outdoor exploration areas. The Gasbot platform has been tested in two different scenarios: an underground corridor, where a pipeline leak was simulated and in a decommissioned landfill site, where an artificial methane emission source was introduced.

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    Gasbot: A mobile robotic platform for methane leak detection and emission monitoring
  • 179.
    Hoang, Dinh-Cuong
    et al.
    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.
    Object-RPE: Dense 3D Reconstruction and Pose Estimation with Convolutional Neural Networks for Warehouse Robots2019In: 2019 European Conference on Mobile Robots, ECMR 2019: Proceedings, IEEE, 2019, article id 152970Conference paper (Refereed)
    Abstract [en]

    We present a system for accurate 3D instance-aware semantic reconstruction and 6D pose estimation, using an RGB-D camera. Our framework couples convolutional neural networks (CNNs) and a state-of-the-art dense Simultaneous Localisation and Mapping (SLAM) system, ElasticFusion, to achieve both high-quality semantic reconstruction as well as robust 6D pose estimation for relevant objects. The method presented in this paper extends a high-quality instance-aware semantic 3D Mapping system from previous work [1] by adding a 6D object pose estimator. While the main trend in CNN-based 6D pose estimation has been to infer object's position and orientation from single views of the scene, our approach explores performing pose estimation from multiple viewpoints, under the conjecture that combining multiple predictions can improve the robustness of an object detection system. The resulting system is capable of producing high-quality object-aware semantic reconstructions of room-sized environments, as well as accurately detecting objects and their 6D poses. The developed method has been verified through experimental validation on the YCB-Video dataset and a newly collected warehouse object dataset. Experimental results confirmed that the proposed system achieves improvements over state-of-the-art methods in terms of surface reconstruction and object pose prediction. Our code and video are available at https://sites.google.com/view/object-rpe.

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    Object-RPE: Dense 3D Reconstruction and Pose Estimation with Convolutional Neural Networks for Warehouse Robots
  • 180. Hristozov, Iasen
    et al.
    Iliev, Boyko
    Örebro University, Department of Technology.
    Eskiizmirliler, Selim
    A combined feature extraction method for an electronic nose2006In: Modern information processing: from theory to applications / [ed] Bernadette Bouchon-Meunier, Giulianella Coletti, Ronald Yager, Amsterdam: Elsevier, 2006, p. 453-466Chapter in book (Other academic)
  • 181.
    Hüllmann, Dino
    et al.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Kohlhoff, Harald
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Erdmann, Jessica
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Neumann, Patrick P.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Control of a spherical parallel manipulator with three degrees of freedom2018In: 35th Danubia-Adria Symposium on Advances in Experimental Mechanics: Extended abstracts / [ed] D. Ş. Pastramă, D. M. Constantinescu, Bukarest, Romania, 2018, p. 159-160Conference paper (Refereed)
    Abstract [en]

    In robotic applications, it is often necessary to orient a sensor quickly. Spherical parallel manipulators (SPM) are well suited for this purpose since they offer superior dynamics and structural stiffness as compared to serial manipulators. To control them, however, the kinematic equations have to be known. In this paper, a SPM with three degrees of freedom and the kinematic equations describing its mechanical properties are presented.

  • 182.
    Hüllmann, Dino
    et al.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Kohlhoff, Harald
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Erdmann, Jessica
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Neumann, Patrick P.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Current-independent torque control of permanent-magnet synchronous motors2017In: Materials Today: Proceedings, E-ISSN 2214-7853, Vol. 4, no 5, p. 5821-5826Article in journal (Refereed)
    Abstract [en]

    A current-independent torque equation for the permanent-magnet synchronous motor (PMSM) aiming at direct-drive servo applications is derived from a first principles model. Instead of measuring currents, all required control parameters are derived from optical incremental encoder measurements. The results are verified on a real system in test series showing the effect of static friction and proving the obtained torque model.

  • 183.
    Hüllmann, Dino
    et al.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Neumann, Patrick P.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Gas Dispersion Fluid Mechanics Simulation for Large Outdoor Environments2019In: 36th Danubia Adria Symposium on Advances in Experimental Mechanics: Extended Abstracts, Pilsen, Czech Republic: Danubia-Adria Symposium on Advances in Experimental Mechanics , 2019, p. 49-50Conference paper (Refereed)
    Abstract [en]

    The development of algorithms for mapping gas distributions and localising gas sources is a challenging task, because gas dispersion is a highly dynamic process and it is impossible to capture ground truth data. Fluid-mechanical simulations are a suitable way to support the development of these algorithms. Several tools for gas dispersion simulation have been developed, but they are not suitable for simulations of large outdoor environments. In this paper, we present a concept of how an existing simulator can be extended to handle both indoor and large outdoor scenarios.

  • 184.
    Hüllmann, Dino
    et al.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Neumann, Patrick P.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Monroy, Javier
    Machine Perception and Intelligent Robotics group (MAPIR), Universidad de Malaga, Spain.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    A Realistic Remote Gas Sensor Model for Three-Dimensional Olfaction Simulations2019In: ISOCS/IEEE International Symposium on Olfaction and Electronic Nose (ISOEN), IEEE, 2019, article id 8823330Conference paper (Refereed)
    Abstract [en]

    Remote gas sensors like those based on the Tunable Diode Laser Absorption Spectroscopy (TDLAS) enable mobile robots to scan huge areas for gas concentrations in reasonable time and are therefore well suited for tasks such as gas emission surveillance and environmental monitoring. A further advantage of remote sensors is that the gas distribution is not disturbed by the sensing platform itself if the measurements are carried out from a sufficient distance, which is particularly interesting when a rotary-wing platform is used. Since there is no possibility to obtain ground truth measurements of gas distributions, simulations are used to develop and evaluate suitable olfaction algorithms. For this purpose several models of in-situ gas sensors have been developed, but models of remote gas sensors are missing. In this paper we present two novel 3D ray-tracer-based TDLAS sensor models. While the first model simplifies the laser beam as a line, the second model takes the conical shape of the beam into account. Using a simulated gas plume, we compare the line model with the cone model in terms of accuracy and computational cost and show that the results generated by the cone model can differ significantly from those of the line model.

  • 185.
    Hüllmann, Dino
    et al.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Paul, Niels
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Kohlhoff, Harald
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Neumann, Patrick P.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Measuring rotor speed for wind vector estimation on multirotor aircraft2018In: Materials Today: Proceedings, E-ISSN 2214-7853, Vol. 5, no 13, p. 26703-26708Article in journal (Refereed)
    Abstract [en]

    For several applications involving multirotor aircraft, it is crucial to know both the direction and speed of the ambient wind. In this paper, an approach to wind vector estimation based on an equilibrium of the principal forces acting on the aircraft is shown. As the thrust force generated by the rotors depends on their rotational speed, a sensor to measure this quantity is required. Two concepts for such a sensor are presented: One is based on tapping the signal carrying the speed setpoint for the motor controllers, the other one uses phototransistors placed underneath the rotor blades. While some complications were encountered with the first approach, the second yields accurate measurement data. This is shown by an experiment comparing the proposed speed sensor to a commercial non-contact tachometer.

  • 186.
    Hüllmann, Dino
    et al.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Paul, Niels
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Neumann, Patrick P.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Motor Speed Transfer Function for Wind Vector Estimation on Multirotor Aircraft2017In: 34th Danubia-Adria Symposium on Advances in Experimental Mechanics: Book of proceedings / [ed] F. Cosmi, Trieste, Italy: EUT Edizioni Università di Trieste , 2017, p. 75-77Conference paper (Refereed)
    Abstract [en]

    A set of equations is derived to estimate the 3D wind vector with a multirotor aircraft using the aircraft itself as a flying anemometer. Since the thrust component is required to compute the wind vector, the PWM signal controlling the motors of the aircraft is measured and a transfer function describing the relation between the PWM signal and the rotational speed of the motors is derived.

  • 187.
    Iannotta, Marco
    et al.
    Örebro University, School of Science and Technology.
    Dominguez, David Caceres
    Örebro University, School of Science and Technology.
    Stork, Johannes Andreas
    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.
    Heterogeneous Full-body Control of a Mobile Manipulator with Behavior Trees2022In: IROS 2022 Workshop on Mobile Manipulation and Embodied Intelligence (MOMA): Challenges and  Opportunities, 2022Conference paper (Refereed)
    Abstract [en]

    Integrating the heterogeneous controllers of a complex mechanical system, such as a mobile manipulator, within the same structure and in a modular way is still challenging. In this work we extend our framework based on Behavior Trees for the control of a redundant mechanical system to the problem of commanding more complex systems that involve multiple low-level controllers. This allows the integrated systems to achieve non-trivial goals that require coordination among the sub-systems.

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    Heterogeneous Full-body Control of a Mobile Manipulator with Behavior Trees
  • 188.
    Iliev, Boyko
    Örebro University, Department of Technology.
    Minimum-time sliding mode control of robot manipulators2002Licentiate thesis, monograph (Other academic)
  • 189.
    Iliev, Boyko
    Örebro University, Department of Technology.
    Minimum-time sliding mode control of robot manipulators2004Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Robot manipulators have a complex and highly nonlinear dynamics, accompanied with a high degree of uncertainty. These properties make them difficult for time-optimal control. The theory of sliding mode control can provide methods, able to cope with the uncertainty and nonlinearity in the system. However, besides the chattering problem it does not provide

    time-optimal behavior. The optimal control theory provides the appropriate design methodology for minimum-time control, but the designed system lacks robustness. In this thesis we combine these two approaches to obtain new control techniques, which have the robust properties of the sliding mode control and a performance, close to the time-optimal control. Two methods for minimum-time sliding mode control based on the concept of maximum slope sliding line are developed with a theoretical proof of their properties.

    In the time-optimal sliding mode control we prove that the time-optimal switching line of a simple linear system (double integrator) can be used as a sliding surface for a complex second order nonlinear system (robot manipulator) if the control gain is sufficiently high. Optimal

    performance is achieved by scaling the surface in such way that the maximum control action is efficiently used.

    The fuzzy minimum-time sliding mode control is developed employing a Takagi-Sugeno

    fuzzy model for the sliding surface. We demonstrate that designs, based on a single sliding line tend to be conservative, due to the nonlinearities in the robot's dynamics. The Takagi-Sugeno model represents the maximum slope sliding lines for different values of the joint angles taking into account the variation in the gravity and inertia terms. This gives a convenient way to provide adaptation and incorporate additional knowledge in the controller design.

    Design procedures for all the methods are developed and evaluated in simulation and in experiments with real robot manipulators.

  • 190.
    Iliev, Boyko
    et al.
    Örebro University, Department of Technology.
    Kalaykov, Ivan
    Örebro University, Department of Technology.
    Minimum-time sliding mode control for second-order systems2004In: Proceedings of the 2004 American control conference, 2004: vol 1, 2004, p. 626-631Conference paper (Refereed)
    Abstract [en]

    Our approach for near time-optimal control is based on Takagi-Sugeno fuzzy model of the maximum slope SMC sliding surface as an adaptive technique for tuning the current slope of the sliding surface to the maximum feasible slope depending on the current state of system. The stability conditions of this method are proved and respective measures about the feasible maximum slope are presented. Experimental results demonstrate the system behaviour.

  • 191.
    Iliev, Boyko
    et al.
    Örebro University, Department of Technology.
    Lindquist, Malin
    Örebro University, Department of Technology.
    Robertsson, Linn
    Örebro University, Department of Technology.
    Wide, Peter
    Örebro University, Department of Technology.
    A fuzzy technique for food- and water quality assessment with an electronic tongue2006In: Fuzzy sets and systems (Print), ISSN 0165-0114, E-ISSN 1872-6801, Vol. 157, no 9, p. 1155-1168Article in journal (Refereed)
    Abstract [en]

    The problem of food- and water quality assessment is important for many practical applications, such as food industry and environmental monitoring. In this article we present a method for fast online quality assessment based on electronic tongue measurements. The idea is implemented in two steps. First we apply a fuzzy clustering technique to obtain prototypes corresponding to good and bad quality from a set of training data. During the second, online step we evaluate the membership of the current measurement to each cluster and make a decision about its quality. The result is presented to the user in a simple and understandable way, similar to the concept of traffic light signals. Namely, good quality is indicated with by a green light, bad quality with a red one, and a yellow light is a warning signal. The approach is demonstrated in two case studies: quality assessment of drinking water and baby food.

  • 192.
    Ishida, Hiroshi
    et al.
    Tokyo University of Agriculture and Technology, Tokyo, Japan.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Matsukura, Haruka
    Tokyo University of Agriculture and Technology, Tokyo, Japan.
    Hernandez Bennetts, Victor
    Örebro University, School of Science and Technology.
    Schaffernicht, Erik
    Örebro University, School of Science and Technology.
    Using Chemical Sensors as 'Noses' for Mobile Robots2016In: Essentials of Machine Olfaction and Taste / [ed] Takamichi Nakamoto, Singapore: John Wiley & Sons, 2016, p. 219-246Chapter in book (Refereed)
    Abstract [en]

    Gas sensors detect the presence of gaseous chemical compounds in air. They are often used in the form of gas alarms for detecting dangerous or hazardous gases. However, a limited number of stationary gas alarms may not be always sufficient to cover a large industrial facility. Human workers having a portable gas detector in their hand needs to be sent to thoroughly check gas leaks in the areas not covered by stationary gas alarms. However, making repetitive measurements with a gas detector at a number of different locations is laborious. Moreover, the places where the gas concentration level needs to be checked are often potentially dangerous for human workers. If a portable gas detector is mounted on a mobile robot, the task of patrolling in an industrial facility for checking a gas leak can be automated. Robots are good at doing repetitive tasks, and can be sent into harsh environments.

  • 193.
    Jadidi, Maani Ghaffari
    et al.
    Fac Engn & IT, Univ Technol Sydney, Sydney NSW, Australia.
    Miro, Jaime Valls
    Fac Engn & IT, Univ Technol Sydney, Sydney NSW, Australia.
    Valencia, Rafael
    Örebro University, School of Science and Technology.
    Andrade-Cetto, Juan
    Inst Robot & Informat Ind, Consejo Superior de Investigaciones Científicas (CSIC), Universitat Politècnica de Catalunya (UPC), Barcelona, Spain.
    Exploration on Continuous Gaussian Process Frontier Maps2014In: 2014 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION (ICRA), IEEE conference proceedings, 2014, p. 6077-6082Conference paper (Refereed)
    Abstract [en]

    An information-driven autonomous robotic exploration method on a continuous representation of unknown environments is proposed in this paper. The approach conveniently handles sparse sensor measurements to build a continuous model of the environment that exploits structural dependencies without the need to resort to a fixed resolution grid map. A gradient field of occupancy probability distribution is regressed from sensor data as a Gaussian process providing frontier boundaries for further exploration. The resulting continuous global frontier surface completely describes unexplored regions and, inherently, provides an automatic stop criterion for a desired sensitivity. The performance of the proposed approach is evaluated through simulation results in the well-known Freiburg and Cave maps.

  • 194.
    Jafari, Raheleh
    et al.
    Centre for Artificial Intelligence Research (CAIR), University of Agder, Grimstad, Norway.
    Razvarz, Sina
    Departamento de Control Automático, CINVESTAV-IPN (National Polytechnic Institute), Mexico City, Mexico.
    Gegov, Alexander
    School of Computing, University of Portsmouth, Portsmouth, UK.
    Paul, Satyam
    Örebro University, School of Science and Technology. School of Engineering and Sciences, Tecnológico de Monterrey, Monterrey, Mexico.
    Fuzzy Modeling for Uncertain Nonlinear Systems Using Fuzzy Equations and Z-Numbers2019In: Advances in Intelligent Systems and Computing / [ed] Lotfi, Ahmad; Bouchachia, Hamid; Gegov, Alexander; Langensiepen, Caroline; McGinnity, Martin, Springer, 2019, Vol. 840, p. 96-107Conference paper (Refereed)
    Abstract [en]

    In this paper, the uncertainty property is represented by Z-number as the coefficients and variables of the fuzzy equation. This modification for the fuzzy equation is suitable for nonlinear system modeling with uncertain parameters. Here, we use fuzzy equations as the models for the uncertain nonlinear systems. The modeling of the uncertain nonlinear systems is to find the coefficients of the fuzzy equation. However, it is very difficult to obtain Z-number coefficients of the fuzzy equations.

    Taking into consideration the modeling case at par with uncertain nonlinear systems, the implementation of neural network technique is contributed in the complex way of dealing the appropriate coefficients of the fuzzy equations. We use the neural network method to approximate Z-number coefficients of the fuzzy equations.

  • 195.
    Jafari, Raheleh
    et al.
    Agder University College, Grimstad, Norway.
    Razvarz, Sina
    National Polytechnic Institute, Mexico City, Mexico.
    Gegov, Alexander
    University of Portsmouth, Portsmouth, UK.
    Paul, Satyam
    National Polytechnic Institute, Mexico City, Mexico.
    Modeling and Control of Uncertain Nonlinear Systems2018Conference paper (Refereed)
    Abstract [en]

    A survey of the methodologies associated with the modeling and control of uncertain nonlinear systems has been given due importance in this paper. The basic criteria that highlights the work is relied on the various patterns of techniques incorporated for the solutions of fuzzy equations that corresponds to fuzzy controllability subject. The solutions which are generated by these equations are considered to be the controllers. Currently, numerical techniques have come out as superior techniques in order to solve these types of problems. The implementation of neural networks technique is contributed in the complex way of dealing the appropriate coefficients and solutions of the fuzzy systems.

  • 196.
    Johansson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    de Vin, Leo J.
    Centre for Intelligent Automation, University of Skövde, Sweden.
    A low cost video see-through head mounted display for increased situation awareness in an augmented environmentManuscript (preprint) (Other academic)
    Abstract [en]

    A head mounted display is developed for use in an augmented reality immersive simulator for virtual training. The simulator requires a video see-through parallax-free display to accurately mix the real and virtual worlds. High field of view is also required to allow use of peripheral vision in order to create a higher sense of awareness for the user. Due to high cost associated with commercial off-the-shelf display systems, a custom solution is designed and developed by combining hardware and software. It’s shown that it’s possible to build a low cost display system that provides the necessary attributes and acceptable compromises for the current type of application.

  • 197.
    Johansson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    de Vin, Leo J.
    Centre for Intelligent Automation, University of Skövde, Sweden.
    An augmented virtuality simulator with an intuitive interface: concept, design and implementationManuscript (preprint) (Other academic)
    Abstract [en]

    This paper describes the design and implementation of a simulator in which users can move untethered in a mixed reality where the boundary between real and virtual objects is minimal. A wide field of view, inexpensive, custom-built video see-through head-mounted display is used in combination with wireless image transfers, natural position displacement and software chroma keying. The result is a simulator that facilitates a high grade of presence with a user interface that allows a high degree of mobility.

  • 198.
    Johansson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    de Vin, Leo J.
    Centre for Intelligent Automation, University of Skövde, Sweden.
    Design and development of an augmented environment with high user mobility for training purposes2008In: Proceedings of the 11th Mechatronics Forum Biennial International Conference: 23 – 25 June 2008, Universith of Limerick, Ireland / [ed] Toal D., Limerick: University of Limerick , 2008Conference paper (Other academic)
    Abstract [en]

    The paper describes the design and development of a novel cost effective simulator for training of situation awareness, strategy and co-operation. By mixing real and virtual realities in combination with wireless and body-mounted hardware, the result is an augmented environment that allows for high physical mobility against a relatively low cost.

  • 199.
    Johansson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    de Vin, Leo J.
    University of Skövde.
    Design and evaluation of an omnidirectional active floor for synthetic environmentsManuscript (preprint) (Other academic)
    Abstract [en]

    In the case of an application with a freely moving user it could be feasible that a simulator that facilitates real running, walking, and crawling can achieve a higher feeling of presence and situation awareness, and therefore potential training effect, compared to a simulator without such facilities. Omnidirectional walking is a research topic that has yielded a number of diverse solutions, but most are still within their prototype stages. Solutions can be expensive, mechanically complicated and in some cases unpractical. The complexity of existing solutions stems in the fact that they are two dimensional, given the normal two dimensional translation of human walking. If instead the problem is viewed upon from an angle of effect, another alternative is available. A two dimensional floor has the purpose to constantly allow translation in any direction, while it also transports the user towards its central region. This is to always have a marginal in all directions for changes in user translation direction or velocity. The effect of this is that a floor could be constructed to always facilitate transportation of the user towards its center, regardless of where on the floor’s surface the user is situated. This paper describes the design and evaluation of a powered omnidirectional floor that reduces the complexity of omnidirectional walking from two dimensions to one dimension. The floor is utilized to create a synthetic environment for training.

  • 200.
    Johansson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    de Vin, Leo J.
    Centre for Intelligent Automation University of Skövde, Skövde, Sweden.
    Omnidirectional robotic telepresence through augmented virtuality for increased situation awareness in hazardous environments2009In: Proceedings 2009 IEEE International Conference on  Systems, Man and Cybernetics, IEEE conference proceedings, 2009, p. 6-11Conference paper (Other academic)
    Abstract [en]

    This paper proposes a novel low-cost robotic telepresence approach to situation awareness, initially aimed for hazardous environments. The robot supports omnidirectional movement, wide field of vision, haptic feedback and binaural sound. It is controlled through an augmented virtuality environment with an intuitive position displacement scheme that supports physical mobility. The operator thereby can conduct work away from danger whilst retaining situation awareness of the real environment.

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