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  • 1151.
    Woltjer, Rogier
    et al.
    Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology.
    Smith, Kip
    Linköping University, Department of Computer and Information Science, CSELAB - Cognitive Systems Engineering Laboratory. Linköping University, The Institute of Technology.
    Constraint recognition in a fire-fighting microworld studyManuscript (preprint) (Other academic)
    Abstract [en]

    This paper describes a method for the recognition of constraints in network-based command and control, and illustrates its application in an experimental study in a command and control microworld. The method uses goals-means test analysis to extract the essential variables that describe the behavior of a command and control team. It juxtaposes these variables in state space representations illustrating constraints and regions for opportunities for action. A series of examples shows how state spaces plots of experimental data can aid in the description of bavior vis-é-vis constraints, and discusses how state space representations may be used o improve control in network-based command and control settings.

  • 1152.
    Woltjer, Rogier
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, CSELAB - Cognitive Systems Engineering Laboratory.
    Smith, Kip
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Industrial Ergonomics.
    Hollnagel, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, CSELAB - Cognitive Systems Engineering Laboratory.
    Constraint recognition and state space representation in collaborative distributed command and control2007In: Swedish Human Factors Network HFN Conference,2006, Linköping: HFN , 2007, p. 72-82Conference paper (Other academic)
  • 1153.
    Wong, Chee Yew
    et al.
    Center for Industrial Production Aalborg University.
    Dahlgaard, Jens Jörn
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Quality Technology and Management.
    Towards Continuous Improvement: A Case of Self-Assessment using the EFQM Excellence Model2004In: International Conference of the Central and Eastern European Countries,2004, 2004Conference paper (Refereed)
  • 1154.
    Wren, Joakim
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Evaluation of three temperature measurement methods used during microwave thermotherapy of prostatic enlargement2004In: International Journal of Hyperthermia, ISSN 0265-6736, E-ISSN 1464-5157, Vol. 20, no 3, p. 300-316Article in journal (Refereed)
    Abstract [en]

    Three temperature measurement methods used during microwave thermotherapy of prostatic enlargement are analysed and evaluated using a phantom model. A commercial transurethral microwave thermotherapy (TUMT) system that uses a radiometric thermometer for temperature control was used to heat the phantom. The transient temperature distribution was obtained by using both fibreoptic (which is considered as gold standard) and thermocouple measurements. Both methods are subject to potential measurement errors caused by electro-magnetic and/or thermal interference. The error sources are analysed and the measurement methods evaluated. The radiometric temperature and especially its relation to the transient temperature distribution was evaluated based on the fibreoptic and thermocouple measurements. These measurements in principle gave equivalent temperature distributions, and thermal interference was concluded to be the largest source of measurement error. The radiometric measurement method gave qualitative rather than quantitative readings of the temperature, and an underestimation of more than 10°C was obtained for some parts of the heated area. The area that gives most of the radiometric signal was relatively close to the catheter in contrast to previously published results.

  • 1155.
    Wren, Joakim
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Microwave Thermotherapy of Prostatic Enlargement, Analysis of Radiometric Thermometry using a Hybrid Bio-Heat Equation2004In: Computer Methods in Biomechanics and Biomedical Engineering, ISSN 1025-5842, E-ISSN 1476-8259, Vol. 7, no 3Article in journal (Refereed)
  • 1156.
    Wren, Joakim
    Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    On modelling and simulation of perfused tissue during thermal treatment: thermal analysis of blood perfusion and lesioning during ablative neurosurgery2000Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Thermal treatment means therapy for which heat is the therapeutic agent. During treatment, the tissue temperature is increased to an injurious temperature (higher than 43 °C for the most widely used treatments). The aim is to reach necrotic temperature in the treatment area and non-lethal temperature outside the same. However, for several reasons this is not possible.

    The thesis deals with thermal treatment from a thermal point of view. The principle aim of the analysis is to obtain the entire temperature field in the treatment area, preferably before the treatment even takes place (temperature prediction). However, it is a complex task to obtain the entire temperature fields which usually varies substantially with both time and space. Parameters of importance are for instance the power supply needed for a certain treatment, the blood perfusion and the heat flux within the treatment area.

    The thesis comprises two different projects; the first project regards modelling and simulation of heat transfer in blood-perfused tissue. The second project concerns modelling and simulation of lesion growth and associated thermal problems during ablative neurosurgery. Throughout the thesis the focus is on modelling, but also experiments are carried out in order to enhance the thermal analysis in the second project.

    In the first project, an important aim is to increase the understanding about the equations (bio-heat equations, BHE's) used for modelling the effect from blood perfusion. A survey as well as a discussion of the equations used the last few decades is carried out. The core of the project is to the BHE's that are variants of the heat conduction equation, and therefore easily implemented in standard thermal simulation packages. An alternative model is proposed in the thesis as a more accurate and flexible tool compared with the most widely used models, the BHE of Pennes and the keff equation.

    In the second project, the focus is on the lesion growth together with the very important temperature measurement, which is used to monitor and control the lesioning process. A simulation model is developed by using input from the in vitro experiments. The model is considered to accurately describe the lesioning process, and very good agreement between experiments and simulations is obtained.

    Furthermore, simulations are used to analyse and evaluate the intra-electrode temperature measurement. The maximum temperature was always located outside the electrode, and therefore, there is always a difference in both time and level between the measured temperature and maximum temperature in the treatment area. The difference is important to quantify, since the lesioning process is directly dependent on the temperature measurement.

  • 1157.
    Wren, Joakim
    et al.
    Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology.
    Eriksson, Ola
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Loyd, Dan
    Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology.
    Analysis of temperature measurement for monitoring radio-frequency brain lesioning2001In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 39, no 2, p. 255-262Article in journal (Refereed)
    Abstract [en]

    During ablative neurosurgery of movement disorders, for instance therapy of Parkinson's disease, temperature monitoring is crucial. This study aims at a quantitative comparison of measurement deviations between the maximum temperature located outside the lesioning electrode and two possible thermocouple locations inside the electrode. In order to obtain the detailed temperature field necessary for the analysis, four finite element models associated with different surroundings and with different power supplies are studied. The results from the simulations show that both the power level and the power density as well as the surrounding medium affect the temperature measurement and the temperature field in general. Since the maximum temperature is located outside the electrode there will always be a deviation in time and level between the measured and the maximum temperature. The deviation is usually 2–7 s and 3–12°C, depending on, for example, the thermocouple location and surrounding medium. Therefore, not only the measured temperature but also the relation between measured and maximum temperature must be accounted for during therapy and device design.

  • 1158.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Erlandsson, B-E
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Simulation of thermal treatment of the prostate using a hybrid bio-heat equation2001In: International Symposium on Computer Methods in Biomechanics and Biomedical Engineering,2001, 2001Conference paper (Refereed)
  • 1159.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation.
    heat transfer analysis model of microwave thermal therapy of the prostate2000In: World Congress on Medical Physics and Biomedical Engineering,2000, 2000Conference paper (Refereed)
  • 1160.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    A hybrid equation for simulation of perfused tissue during thermal treatment2001In: International Journal of Hyperthermia, ISSN 0265-6736, E-ISSN 1464-5157, Vol. 17, no 6, p. 483-498Article in journal (Refereed)
    Abstract [en]

    Bio-heat equations (BHEs) are necessary for predicting tissue temperature during thermal treatment. For some applications, however, existing BHEs describe the convective heat transfer by the blood perfusion in an unsatisfactory way. The two most frequently used equations, the BHE of Pennes and the keff equation, use for instance either a heat sink or an increased thermal conductivity in order to account for the blood perfusion. Both these methods introduce modelling inaccuracies when applied to an ordinary tissue continuum with a variety of vessel sizes. In this study, a hybrid equation that includes both an increased thermal conductivity and a heat sink is proposed. The equation relies on the different thermal characteristics associated with small, intermediate and large sized vessels together with the possibilities of modelling these vessels using an effective thermal conductivity in combination with a heat sink. The relative importance of these two terms is accounted for by a coefficient ▀. For ▀ = 0 and ▀ = 1, the hybrid equation coincides with the BHE of Pennes and the keff equation, respectively. The hybrid equation is used here in order to simulate temperature fields for two tissue models. The temperature field is greatly affected by ▀, and the effect is dependent on, e.g. the boundary conditions and the power supply. Since the BHE of Pennes and the keff equation are included in the hybrid equation, this equation can also be useful for evaluation of the included equations. Both these heat transfer modes are included in the proposed equation, which enables implementation in standard thermal simulation programmes.

  • 1161.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Transient temperature response of the myocardium investigated by the hybrid bioheat model2004In: IASME Transactions, ISSN 1790-031X, Vol. 1, no 3, p. 560-565Article in journal (Refereed)
  • 1162.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics . Linköping University, The Institute of Technology.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Sjödin, Jörgen
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Energy Systems.
    Erlandsson, B-E
    A Heat Transfer Analysis of Microwave Thermal Therapy of the Prostate2000In: Annual International Conference of the IEEE Engineering in Medicine biology Society,2000, 2000Conference paper (Other academic)
  • 1163.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Investigation of medical thermal treatment using a hybrid bio-heat model2004In: 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society,2004, 2004Conference paper (Refereed)
  • 1164.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Persson, Peter
    IKP .
    A method for determination of intra-valve heat transfer in thermostatic mixing valves2006In: International Conference on Heat and Mass Transfer,2006, Miami, Florida, USA: WSEAS/IASME , 2006, p. 46-Conference paper (Refereed)
    Abstract [en]

      

  • 1165.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Persson, Peter
    IKP .
    Thermostatic mixing valves - A method for non-disturbing intra-valve heat transfer estimation2006In: Journal of Advanced Nursing, ISSN 0309-2402, E-ISSN 1365-2648, Vol. 1, p. 59-64Article in journal (Refereed)
    Abstract [en]

      

  • 1166.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Persson, Peter
    IKP .
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Thermostatic Mixing Valves - Modeling and simulation of the thermostat under real operating conditions2006In: WSEAS Transactions on Circuits and Systems, ISSN 1109-2734, Vol. 1, p. 56-61Article in journal (Refereed)
    Abstract [en]

       

  • 1167.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Persson, Peter
    IKP .
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Thermostatic Mixing Valves - Thermostatic temperature distribution during various operating conditions2006In: International Conference on Heat and Mass Transfer,2006, Miami, Florida, Usa: WSEAS/IASME , 2006, p. 42-Conference paper (Refereed)
    Abstract [en]

      

  • 1168.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Sjödin, Jan-Gunnar
    Erlandsson, Björn-Erik
    Eliasson, Tomas
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Accuracy of Temperature Measurement During Transurethral Hyperthermia Treatment och the Prostate1999In: Proc of BMES/BMBS99,1999, 1999Conference paper (Other academic)
  • 1169.
    Wren, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Svensson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Gårdhagen, Roland
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Engstrand, Ulf
    Learning more with demonstration based education2005In: CUL-dagen 2005,2005, 2005Conference paper (Other academic)
  • 1170. Xiong, C
    et al.
    Hök, Bertil
    Strömberg, Tomas
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    A bioacoustic method for timing of respiration at cardiac investigations1995In: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 15, p. 151-157Article in journal (Refereed)
  • 1171.
    Yong, Yang
    et al.
    College of Information Central South University, Changsa, China.
    An, Lou
    Changsa University, Changsa, China.
    Rydberg, Karl-Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    Fuzzy sliding mode variable structure control for an electro-hydraulic servo system2005In: 9th Scandinavian international conference on fluid power,2005, Linköping: Linköpings universitet , 2005, p. 74-Conference paper (Refereed)
  • 1172.
    Yong, Yang
    et al.
    College of Information Central South University, Changsa, China.
    Rydberg, Karl-Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    Intelligent control for artificial damping in hydraulic crane system under load dynamics2005In: ICFP05,2005, 2005Conference paper (Other academic)
  • 1173.
    Zachrison, Anders
    Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Selection schemes and neural networks in adaptive real-time control: predictive simulation adaptive control2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The vision of self-aware machines was the starting point of this work. The idea is a machine having knowledge about itself and its surrounding environment, being able to react to changes in the environment. To support this vision, a number of engineering disciplines need to be merged and the control strategy "predictive simulation adaptive control'', PSAC, developed.

    The focus of the thesis is the synthesis of a number of algorithms and ideas from different engineering disciplines and fields. The main disciplines that the work is based on are simulation techniques, selection schemes and neural networks; all of these combined with the constraints imposed by the real-time demands of control systems.

    Selection schemes, or optimisation algorithms, are introduced here and used directly for real-time control of the test system, a rod-less pneumatic cylinder. The selection process is primarily based on genetic algorithms and the outcome of numerous simulations of the system for different possible control signals.

    Neural networks in general, and the version used here in particular, the Kohonen self-organising map, is widely used for classification and storage of information. Here it is used first to approximate friction in a rod-less pneumatic cylinder, and later on, possible ways to utilise this technique for condition monitoring are briefly discussed.

    Real-time systems and programming are a necessity when designing modern control systems. From the real-time constraints, special demands are put on the implemented algorithms and ideas.

    By bringing all this together, piece by piece, the vision comes a little bit closer. One step on the path, is the PSAC control concept proposed here. The control concept is successfully implemented and tested on a position servo consisting of a pneumatic rod-less cylinder controlled by on/off-valves.

    List of papers
    1. Simulation and selection schemes for real-time control of a pneumatic cylinder
    Open this publication in new window or tab >>Simulation and selection schemes for real-time control of a pneumatic cylinder
    2003 (English)In: The Bath Workshop on Power Transmission & Motion Control, PTMC' 03 / [ed] C. R. Burrows & K. A. Edge, London, Bury St Edmunds, UK: Professional Engineering Publishing , 2003, p. 307-318Conference paper, Published paper (Other academic)
    Abstract [en]

    Simulation techniques are used in this project to predict the dynamic behaviour of a rod-less pneumatic cylinder in real-time. This forms a controller for position control of the cylinder using selection and optimisation methods based on simulation results. This paper reports on the current state of ongoing research, emphasising extending the use of simulation techniques within real-time applications. A test setup is presented with a pneumatic cylinder controlled by four 3/2 on/off valves. The valves form a modulating energy input to the cylinder. The valve switch timing is established by short simulations of different possible scenarios. A selection scheme is then applied and the most suitable simulation forms the control signals for the valves. Experimental results together with the corresponding simulations are presented.

    The presented setup uses the real-time operating system Linux/RTAI to host the simulation, selection and control software.

    Place, publisher, year, edition, pages
    London, Bury St Edmunds, UK: Professional Engineering Publishing, 2003
    Keywords
    Pneumatic, simulation, selection scheme, control, real-time
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-24282 (URN)3898 (Local ID)3898 (Archive number)3898 (OAI)
    Conference
    The Bath Workshop on Power Transmission & Motion Control, PTMC' 03, Bath, United Kingdom, 10th-12th September, 2003
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-20
    2. Simulation and Selection Schemes in Machine Self-Awareness, a Position Control Case Study
    Open this publication in new window or tab >>Simulation and Selection Schemes in Machine Self-Awareness, a Position Control Case Study
    2004 (English)In: Power Transmission and Motion Control. PTMC 2004 / [ed] C R Burrows, K A Edge, D N Johnston, London, Bury St Edmunds, UK: Professional Engineering Publishing , 2004, p. 307-318Conference paper, Published paper (Other academic)
    Abstract [en]

    Simulation techniques for numerical prediction of dynamic behaviour of a sub-system may be combined with different types of selection schemes at a controller loop level. This constitutes a way of using physical simulation models as a prediction scheme for machine control. This is similar to model-based control techniques but introduces the flexibility of switching control objectives and limitations on the fly. Such a control strategy may be of interest in applications where the environment is not fully identified or may change in an unpredictable way. A sudden change in working conditions due to a failure in the system or component itself is an example. The machine then needs to have some degree of readiness for unforeseen conditions. This is a typical scenario in remote mobile robotics and machinery in hazardous environments. Some level of self-awareness in the controller of the machine is desirable.

    This paper describes a case study of techniques suitable for such machine self awareness. Simulation techniques are used in this project to predict the dynamic behaviour of a rod-less pneumatic cylinder in real-time. This forms a controller for position control of the cylinder using selection and optimisation methods based on simulation results. Previous work has shown that the method works when using grid selection schemes of a reduced set of control signals. In this paper this is further extended using genetic algorithm selection schemes.

    Possible applications for the proposed scheme are discussed and a simple selection scheme based upon genetic algorithms is proposed.

    Place, publisher, year, edition, pages
    London, Bury St Edmunds, UK: Professional Engineering Publishing, 2004
    Keywords
    Machine Self-Awareness, simulation
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-23249 (URN)2666 (Local ID)9781860584664 (ISBN)2666 (Archive number)2666 (OAI)
    Conference
    The Bath Workshop on Power Transmission & Motion Control, PTMC' 04, Bath, United Kingdom, 1st-3rd September, 2004
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-20
    3. Self-Organising Maps for Illustration of Friction in a Pneumatic Cylinder
    Open this publication in new window or tab >>Self-Organising Maps for Illustration of Friction in a Pneumatic Cylinder
    2005 (English)In: 9th Scandinavian International Conference on Fluid Power, SICFP’05, 2005, p. 80-81Conference paper, Published paper (Other academic)
    Abstract [en]

    Friction exists in virtually every mechanical system. A great many models for prediction and simulation of friction exist. However, due to the high non-linear nature of friction, especially stick-slip friction, there exists a trade-off between simplicity and accuracy in the predictions, also due to difficulties in building an accurate model.

    Here an approach to estimation of friction based on accumulated knowledge, using previous measurements and estimations based on these measurements, is discussed. In this approach, a special kind of neural networks, is used. The type of neural network used here is a Kohonen self-organising map. Results from the trained map are used to illustrate how friction relates to states in the pneumatic cylinder. The structure in the map resulting from the different states is also discussed, interpreted and illustrated.

    Keywords
    Self-organizing maps, friction, pneumatic
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-12975 (URN)
    Conference
    9th Scandinavian International Conference on Fluid Power, SICFP’05, Linköping, Sweden, 1st-2nd June, 2005
    Available from: 2008-02-26 Created: 2008-02-26 Last updated: 2017-12-20
  • 1174.
    Zachrison, Anders
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    Rösth, Marcus
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    Ölvander, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Machine Design.
    Werndin, Ronnie
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    Evolve - A Vehicle Based Test Platform for Active Rear Axle Camber and Steering Control2003In: SAE 2003 World Congress,2003, Detroit, USA: SAE , 2003Conference paper (Refereed)
  • 1175.
    Zachrison, Anders
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    Rösth, Marcus
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    Ölvander, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Machine Design.
    Werndin, Ronnie
    IKP Tekniska fakulteten.
    Evolve-A Vehicle-Based Test Platform for Active Rear Axle Camber and Steering Control2003In: SAE Transactions, ISSN 0096-736X, Vol. 112, no 6, p. 690-695Article in journal (Refereed)
  • 1176.
    Zachrison, Anders
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering.
    Sethson, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    Predictive Simulation Adaptive Control for Pneumatic Components2007In: 22nd IEEE International Symposium on Intelligent Control, part of IEEE Multi-conference on Systems and Control,2007, Singapore: IEEE , 2007, p. 345-Conference paper (Refereed)
  • 1177.
    Zachrison, Anders
    et al.
    Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Sethson, Magnus
    Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Simulation and selection schemes for real-time control of a pneumatic cylinder2003In: The Bath Workshop on Power Transmission & Motion Control, PTMC' 03 / [ed] C. R. Burrows & K. A. Edge, London, Bury St Edmunds, UK: Professional Engineering Publishing , 2003, p. 307-318Conference paper (Other academic)
    Abstract [en]

    Simulation techniques are used in this project to predict the dynamic behaviour of a rod-less pneumatic cylinder in real-time. This forms a controller for position control of the cylinder using selection and optimisation methods based on simulation results. This paper reports on the current state of ongoing research, emphasising extending the use of simulation techniques within real-time applications. A test setup is presented with a pneumatic cylinder controlled by four 3/2 on/off valves. The valves form a modulating energy input to the cylinder. The valve switch timing is established by short simulations of different possible scenarios. A selection scheme is then applied and the most suitable simulation forms the control signals for the valves. Experimental results together with the corresponding simulations are presented.

    The presented setup uses the real-time operating system Linux/RTAI to host the simulation, selection and control software.

  • 1178.
    Zachrison, Anders
    et al.
    Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Sethson, Magnus
    Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Simulation and Selection Schemes in Machine Self-Awareness, a Position Control Case Study2004In: Power Transmission and Motion Control. PTMC 2004 / [ed] C R Burrows, K A Edge, D N Johnston, London, Bury St Edmunds, UK: Professional Engineering Publishing , 2004, p. 307-318Conference paper (Other academic)
    Abstract [en]

    Simulation techniques for numerical prediction of dynamic behaviour of a sub-system may be combined with different types of selection schemes at a controller loop level. This constitutes a way of using physical simulation models as a prediction scheme for machine control. This is similar to model-based control techniques but introduces the flexibility of switching control objectives and limitations on the fly. Such a control strategy may be of interest in applications where the environment is not fully identified or may change in an unpredictable way. A sudden change in working conditions due to a failure in the system or component itself is an example. The machine then needs to have some degree of readiness for unforeseen conditions. This is a typical scenario in remote mobile robotics and machinery in hazardous environments. Some level of self-awareness in the controller of the machine is desirable.

    This paper describes a case study of techniques suitable for such machine self awareness. Simulation techniques are used in this project to predict the dynamic behaviour of a rod-less pneumatic cylinder in real-time. This forms a controller for position control of the cylinder using selection and optimisation methods based on simulation results. Previous work has shown that the method works when using grid selection schemes of a reduced set of control signals. In this paper this is further extended using genetic algorithm selection schemes.

    Possible applications for the proposed scheme are discussed and a simple selection scheme based upon genetic algorithms is proposed.

  • 1179.
    Zachrison, Anders
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    Sethson, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    Simulering och optimering för styrning i realtid2003In: Hydraulikdagar 2003, HD03,2003, Linköping, Sweden: Linköpings universitet , 2003Conference paper (Refereed)
  • 1180.
    Zhai, Shumin
    et al.
    IDA IBM Almaden Research Center.
    Accot, Johnny
    IBM Almaden Research Center.
    Woltjer, Rogier
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Industrial Ergonomics.
    Human Action Laws in Electronic Virtual Worlds: An Empirical Study of Path Steering Performance in VR2004In: Presence - Teleoperators and Virtual Environments, ISSN 1054-7460, E-ISSN 1531-3263, Vol. 13, no 2, p. 113-127Article in journal (Refereed)
    Abstract [en]

    This paper is concerned with simple human performance “laws of action” for three classes of tasks—pointing, crossing, and steering, as well as their applications in Virtual Reality research. In comparison to Fitts' law of pointing, the “law of steering”— the quantitative relationship between human temporal performance and the movement path's spatial characteristics—has been notably under investigated. After a review of research on the law of steering in different domains and time periods, we examine the applicability of the law of steering in a VR locomotion task. Participants drove a virtual vehicle in a virtual environment on paths whose shape and width were systematically manipulated. Results showed that the law of steering indeed applies to locomotion in Virtual Environments. Participants' mean trial completion times linearly correlated (r2 between 0.985 and 0.999) with an index of difficulty quantified as path length to width ratio for the straight and circular paths used in this experiment. On average both the mean and the maximum speeds of the participants were linearly proportional to path width. Such human performance regularity provides a quantitative tool for 3D human-machine interface design and evaluation. We also propose to use the law-of-steering model in Virtual Reality manipulation tasks such as the “ring and wire” task in the future.

  • 1181.
    Zinko, Heimo
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Energy Systems.
    Mindre koldioxid med solvärme2005In: Energimagasinet : teknik, ekonomi, miljö, ISSN 0348-9493, Vol. 7, p. 26-30Article in journal (Other (popular science, discussion, etc.))
  • 1182.
    Zinko, Heimo
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Energy Systems.
    The role of solar energy in the light of a deregulated European energy system2005In: ISES-Conference,2005, 2005Conference paper (Refereed)
  • 1183.
    Zinko, Heimo
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Gebremedhin, Alemayehu
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Klasson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Energy Systems.
    Reduction of CO2 emissions in district heating areas2008In: 10th World Renewable Energy Congress WRECX,2008, 2008, p. 2675-2680Conference paper (Refereed)
  • 1184.
    Zinko, Heimo
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Energy Systems.
    Söderberg, Sven-Olof
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Energy Systems.
    Fahlén, Elsa
    Gebremedhin, Alemayehu
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Energy Systems.
    Integration av absorptionsmaskiner i fjärrvärmesystem2004Report (Other academic)
  • 1185.
    Åman, Robin
    Linköping University, Department of Mechanical Engineering.
    Design of an End Effector for Drilling in Automated Processes2006Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    In an attempt to solve a problem concerning drilling, a project was started at the universities in Linköping and Lund. As a part of the project this thesis aims to help solve the drilling problem. The goal of this thesis is to design an end effector that will help avoid slipping when drilling. The methods used were taken from David G. Ullman’s book The Mechanical Design Process. Members involved in the project were interviewed to get an understanding of the task. With that done the concept generation phase began, resulting in several concepts. With the use of evaluation methods, such as feasibility judgment and Go/No-Go screening, a final concept emerged. All of the parts and details of the concept were designed with respect for the customers’ requirements and demands.

    Download full text (pdf)
    FULLTEXT01
  • 1186.
    Ödkvist, Magnus
    Linköping University, Department of Mechanical Engineering.
    Konceptstudie av kombinerad nödgenerator-trädgårdsredskap: Concept Study of a Combined Emergency Generator-Garden tool2005Student paper second termStudent thesis
    Abstract [en]

    The present study concerns a concept development of a product idea that Bengt Magnuson, associate professor, had when a heavy storm caused a widespread power failure of long duration. With a basic power-producing unit one should be able to get through a power loss. The product could also be useful for other tasks if different modules are connected, e g grass mower or snow-blower.

    According to the product idea the basic unit will be able to produce electric power enough for a fridge, freezer, TV, and a few electric lamps. Normally the basic unit can be used e g as a mower, when such a module is attached. An increased number of tasks would make the contraption useful and tempting for those who do not own an electrical power set in reserve. The study was limited, not involving the construction and characteristics of the power set, as such systems already exist. Power sets will be discussed according to size, weight, and effect to estimate there suitability in the base unit. Also was a consumers investigation not Per-formed, as the study is supposed to produce a basis for such an enquiry.

    During the concept development, five ideas were compared in order to reach the best solution. This solution was compared to the alternative solutions which were brought forward at the critical scrutinisation of the product idea.

    The result that was reached implied that the product would deflect buyers due to the considerable weight. Even if the weight would be reduced by making the generator unit lighter, two alternative solutions were considered better. One of them would use an alternator and put it on a modified mower with an extra shaft-coupling. The other one would be to add an alternator generator to a system already on the market, where the same motor could be moved between different products.

    In conclusion: One should not continue further development of the original product idea but instead use one of the alternative solutions and perform a consumer’s investigation on that one. It is important as a need for an electricity supply in reserve seems to exist for many people outside the central urban areas.

    Download full text (pdf)
    FULLTEXT01
  • 1187.
    Ölund, Fredrik
    Linköping University, Department of Mechanical Engineering.
    San Pedro S.A.: Taking the first step to a safer work environment2006Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    As a part of improving the production, the Bolivian door manufacturer San Pedro S.A. needs to develop their level of industrial safety. Today their safety level is considered to be almost non-existing. Together with CADEFOR, San Pedro wishes for a handbook that show them how to work with industrial safety, how to implement it and were to begin.

    Much needs to be done at San Pedro and the task has been to show both them and CADEFOR which parts San Pedro need to focus on to increase the overall safety.

    It is considered important that they chose to start with the most crucial areas but the aim is that they will, during a period of time, attend to all problem areas mentioned.

    The first thing San Pedro needs to do is to form an aim for the safety work. This means setting up a policy and routines for the ongoing work.

    Secondly they should start working with improving the fire security, informing the personal about the risks they are exposed to. Further they should educate attendants in first aid, use the protection on the machines available and create a better luminosity environment.

    Download full text (pdf)
    FULLTEXT01
  • 1188.
    Ölvander, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Machine Design .
    Krus, Petter
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Machine Design.
    A multi-objective optimization approach to aircraft preliminary design2004In: SAE Transactions Journal of Aerospace, p. 454-460Article in journal (Refereed)
  • 1189.
    Ölvander, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Machine Design.
    Krus, Petter
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Machine Design.
    Optimizing the Optimization - A Method for Comparison of Optimization Algorithms2006In: AIAA Multidisciplinary Design Optimization Specialists Conference,2006, Newport, RI; USA: AIAA , 2006Conference paper (Refereed)
  • 1190.
    Östlin, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Assembly technology.
    Effectiveness in the Closed-Loop Supply Chain: A Study Regarding Remanufacturing2005In: EEE International Engineering Management Conference IEMC 2005,2005, 2005Conference paper (Refereed)
  • 1191.
    Östlin, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Assembly technology.
    Lindahl, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Environmental Technique and Management.
    Sundin, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Assembly technology.
    Managing Functional Sales Systems - Important Aspects for Making Functional Sales an Effective Business System2005In: 10th International Conference of Sustainable Innovation,,2005, 2005Conference paper (Refereed)
  • 1192.
    Östlin, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering.
    Östlin, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Assembly technology.
    Lindahl, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering.
    Lindahl, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Environmental Technique and Management.
    Sundin, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering.
    Sundin, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Assembly technology.
    Managing Functional Sales Systems - Important Aspects for Making Functional Sales an Effective Business System2006In: 10th International Conference of Sustainable Innovation,2006, Linköping: Linköpings universitet , 2006Conference paper (Refereed)
21222324 1151 - 1192 of 1192
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