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- Eriksson, Magnus G., et al.
(author)
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A Haptic and Virtual Reality Skull Bone Surgery Simulator
- 2005
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Conference paper (peer-reviewed)abstract
- The work presented in this paper gives an introduction to the development of a simulator system based on a virtual reality representation of the human skull, from which both haptic and visual feedback is generated to simulate and animate the milling process in skull bone surgery. The system will be used to educate and train surgeons to do complicated skull bone operations, such as removal of cancer tumors. The skull bone data is taken from a CT-scan and visualized using a modified Marching cubes algorithm. Different haptic rendering algorithms of the bone milling process are discussed for implementation. An energy-based approach is used for modeling of material removed during the milling process. The topic is still young and unexplored; hence this paper discusses the different parts a bone milling VRsystem consists of and gives an insight into problems occurring in a VR bone milling process and presents solutions for some of these problems.
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| 2. |
- Eriksson, Magnus G., et al.
(author)
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Haptic Simulation of the Milling Process in Temporal Bone Operations
- 2005
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In: Medicine Meets Virtual Reality 13. - : IOS Press. - 9781586034986 ; , s. 133-136
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Conference paper (peer-reviewed)abstract
- A VR-simulation system for educating surgeons of the temporal bone milling processes is presented in this paper. E. g. the milling process that occurs during the removal of certain cancer tumors in the brain. The research project is recently started up and this paper is an introduction to the bone milling simulation topic. We present how the graphical rendering of the temporal bone is done. Acquired data are managed using the Marching cubes algorithm to perform a visual representation. A re-production of iso-surfaces will represent the material removal occurred during the milling process. Force models are discussed and will be implemented in the H3D API, which is used to control the virtual simulation and collision detection. Equipment, implementation and future work are also presented in the paper.
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| 4. |
- Flemmer, Henrik, 1972-
(author)
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Control Design and Performance Analysis of force Reflective Teleoperators - A Passivity Based Approach
- 2004
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Doctoral thesis (other academic/artistic)abstract
- In this thesis, the problem of controlling a surgical masterand slave system with force reflection is studied. The problemof stiff contacts between the slave and the environment isgiven specific attention. The work has been carried out at KTHbased on an initial cooperation with Karolinska Sjukhuset. Theaim of the over all project is to study the possibilities forintroduction of a force reflective teleoperator in neurologicalskullbase operations for the particular task of bone millingand thereby, hopefully, increase patient safety, decreasesurgeon workload and cost forthe society. The main contributions of this thesis are: Derivation of a dynamical model of the master andoperator’s finger system and, experimental identificationof ranges on model parameter values. Based on this model, theinteraction channel controllers optimized for transparency arederived and modified to avoid the influence of the uncertainmodel parameters. This results in a three channel structure. Todecrease the influence of the uncertain parameters locally atthe master, a control loop is designed such that the frequencyresponse of the reflected force is relatively unaffected by theuncertainties, a result also confirmed in a transparencyanalysis based on the H-matrix. The developed teleoperatorcontrol structure is tested in experiments where the operatorcould alter the contact force without facing any problems aslong as the slave is in contact with the environment. As a result of the severe difficulties for the teleoperatorto move from free space motion to in-contact manipulationwithout oscillative behaviour, a new detection algorithm basedon passivity theory is developed. The algorithm is able todetect the non-passive behaviour of the actual teleoperatorinduced by the discrete change in system dynamics occurring atthe contact instant. A stabilization controller to be activatedby the detection algorithm is designed and implemented on themaster side of the teleoperator. The detection algorithm andthe stabilization controller are shown highly effective in realexperiments. All major research results presented in the thesis have beenverified experimentally. KeywordsTeleoperator, Force Feedback, Passivity, StiffContacts, Control, Robustness, Transparency, Bone Milling,Uncertainty
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| 7. |
- Sjöstedt, Carl-Johan, 1975-, et al.
(author)
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Evaluation of Auxiliary Device Efficiency in Heavy Vehicle Application
- 2013
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In: Proceedings of the ASME Design Engineering Technical Conference. - 9780791855843
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Conference paper (peer-reviewed)abstract
- To investigate the energy consumption related to auxiliary devices, as a basis for optimizing the auxiliary systems’ layout and identifying potential for fuel consumption reduction, a study has been carried out at Scania CV AB. The following auxiliary devices have been investigated: Alternator, water pump, cooling fan, air compressor, air conditioning compressor, oil pump and power steering pump. Those auxiliary devices represent 5–7% of the total fuel consumption in long haulage truck applications, while for a city bus the figure could be as high as 50%. One of the challenges of evaluating the fuel consumption of auxiliary devices is the variance: it depends on many factors including road data, driver profile, ambient conditions (temperature, pres- sure, precipitation) and more. To investigate this variance, test data collected from the Scania test fleet has been analyzed. The data are used as input to a MATLAB/Simulink model of the aux- iliary systems. This way, a large population of trucks has been investigated, for many driving cycles under realistic conditions. A general model for reducing fuel consumption for auxiliary sys- tems has been developed.
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