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  • 1.
    Arbat, Anna
    et al.
    SIC, Departament d’Electrònica, Universitat de Barcelona, Barcelona, Spain.
    Edqvist, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Casanova Mohr, Raimon
    SIC, Departament d’Electrònica, Universitat de Barcelona, Barcelona, Spain.
    Brufau, Jordi
    SIC, Departament d’Electrònica, Universitat de Barcelona, Barcelona, Spain.
    Canals, J.
    SIC, Departament d’Electrònica, Universitat de Barcelona, Barcelona, Spain.
    Samitier, Joseph
    SIC, Departament d’Electrònica, Universitat de Barcelona, Barcelona, Spain.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dieguez, Angle
    SIC, Departament d’Electrònica, Universitat de Barcelona, Barcelona, Spain.
    Design and validation of the control circuits for a micro-cantilever tool for a micro-robot2009In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 153, no 1, p. 76-83Article in journal (Refereed)
    Abstract [en]

    The objective of this paper is to present the design and validation of a cantilever-based contact sensing system for a micro-robot. Key elements of the fabrication process of the sensor and the electrical model extraction used to design the control electronics are described. The architecture used for the sensor corresponds to a micro-cantilever fabricated of piezoelectric-polyvinylidene fluoride-trifluoroethylene stacked in a multilayer structure with the possibility of both actuating and sensing. A lumped electro mechanical equivalent model of the micro-cantilever was used to design the control electronics for the cantilever. A driving signal from, the control system is used to vibrate the cantilever at its first mechanical resonance frequency. The control system contains an analog front-end to measure the sensor output signal and a digital control unit designed to track and keep the resonance frequency of the cantilever. By integrating the cantilever control system is integrated in the application specified integrated circuit used to control of the circuit is simplyfied and very compact. Experimental results show a similar behavior between the electrical model and the fabricated system, and the deviations between the model and the measured structure are analyzed. The results also show that the designed control system is capable to detect the resonance frequency of the system and to actuate despite small deviations in process parameters of different batches of cantilevers. The whole system was designed to be integrated into an autonomous micro-robot, although it can be used in other applications.

  • 2. Brufau, J
    et al.
    Puig-Vidal, M
    Lopez-Sanchez, J
    Snis, Niklas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Driesen, W
    Gao, J
    Velten, T
    MICRON: Small Autonomous Robot for Cell Manipulation Applications2005In: 2005 IEEE International Conference on Robotics and Automation, Barcelona, Spain April 2005, 2005Conference paper (Refereed)
  • 3.
    Edqvist, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Snis, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Casanova Mohr, Raimon
    SiC, Electronics Department, University of Barcelona, Barcelona, Spain.
    Scholz, Oliver
    IBMT, Fraunhofer Institute for Biomedical Engineering, St Ingbert, Germany.
    Corradi, Paolo
    Scuola Superiore Sant’Anna, Pisa, Italy.
    Gao, Jianbo
    IBMT, Fraunhofer Institute for Biomedical Engineering, St Ingbert, Germany.
    Di´eguez, Angel
    SiC, Electronics Department, University of Barcelona, Barcelona, Spain.
    Wyrsch, Nicolas
    Institut de Microtechnique, University of Neuchˆatel, Neuchˆatel, Switzerland.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Evaluation of building technology for mass producible millimetre-sized robots using flexible printed circuit boards2009In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 19, no 7, p. 11pp-Article in journal (Refereed)
    Abstract [en]

    Initial tests of a building technology for a compact three-dimensional mass produciblemicrorobot are presented. The 3.9 × 3.9 × 3.3 mm3 sized prototype robot represents amicrosystem with actuators, sensors, energy management and integrated electronics. Theweight of a folded robot is 65 mg and the total volume is less than 23 mm3. The design of theinterfaces of the different modules in the robot, as well as the building technology, isdescribed. The modules are assembled using conductive adhesive with industrial surfacemounting technology on a thin double-sided flexible printed circuit board. The final shape ofthe microrobots is achieved by folding the flexible printed circuit board twice. Electrical andmechanical studies are performed to evaluate the assembly and it is concluded that thetechnology can be used for this type of microsystem. Several issues using the presentedassembly technique are identified and addressed.

  • 4.
    Edqvist, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Snis, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Gentle dry etching of P(VDF-TrFE) multilayer micro actuator structures by use of an inductive coupled plasma2008In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 18, no 1, p. 015007-Article in journal (Refereed)
    Abstract [en]

    To fully utilize the actuator properties of poly(vinylidenefluoride) (P(VDF))-based polymers, the electric field has to be rather high and one way to accomplish this, in particular with low voltage drive signals, is to build multilayered structures. This paper focuses on how to structure poly(vinylidenefluoride-trifluoroethylene) P(VDF-TrFE) by presenting an etch method to create multilayered miniaturized actuators, with intermediate aluminium electrodes. To create inter-connect areas for the multilayer electrodes, a modified Bosch process in an inductive couple plasma (ICP) etcher is used to remove all P(VDF-TrFE) not covered by the electrodes. Since each electrode mask is slightly different from the others, the result is a staircase-like inter-electrode contact area that is connected from above using a conductive adhesive. The developed ICP etch results in high selective etching and a good agreement between theoretical and measured capacitance values. The manufactured cantilevers, consisting of a multilayer on top of a flexible printed circuit (FPC) board, were tested and the resonant stroke was confirmed to agree with expected values. The successful establishment of interlayer connections between the electrodes open up the possibility for batch fabrication of cheap low voltage micro actuators built on a standard substrate used in millions of commercial products. 2008 IOP Publishing Ltd.

  • 5. Eisinberg, A
    et al.
    Izzo, I
    Menciassi, A
    Houston, K
    Valdastri, P
    Dario, P
    Gustafsson, R
    Simu, U
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Design and shape deposition manufacturing (SDM) fabrication of a PZT-actuated tool for micromanipulation2005In: International Symposium on Computational Intelligence in Robotics and Automation, 2005. CIRA 2005. Proceedings. 2005 IEEE, 2005Conference paper (Refereed)
  • 6. Evander, Mikael
    et al.
    Johansson, Linda
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Lilliehorn, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Piskur, Jure
    Lindvall, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Almqvist, Monica
    Laurell, Thomas
    Nilsson, Johan
    Noninvasive acoustic cell trapping in a microfluidic perfusion system for online bioassays2007In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 79, no 7, p. 2984-2991Article in journal (Refereed)
    Abstract [en]

    Techniques for manipulating, separating, and trapping particles and cells are highly desired in today's bioanalytical and biomedical field. The microfluidic chip-based acoustic noncontact trapping method earlier developed within the group now provides a flexible platform for performing cell- and particle-based assays in continuous flow microsystems. An acoustic standing wave is generated in etched glass channels (600x61 microm2) by miniature ultrasonic transducers (550x550x200 microm3). Particles or cells passing the transducer will be retained and levitated in the center of the channel without any contact with the channel walls. The maximum trapping force was calculated to be 430+/-135 pN by measuring the drag force exerted on a single particle levitated in the standing wave. The temperature increase in the channel was characterized by fluorescence measurements using rhodamine B, and levels of moderate temperature increase were noted. Neural stem cells were acoustically trapped and shown to be viable after 15 min. Further evidence of the mild cell handling conditions was demonstrated as yeast cells were successfully cultured for 6 h in the acoustic trap while being perfused by the cell medium at a flowrate of 1 microL/min. The acoustic microchip method facilitates trapping of single cells as well as larger cell clusters. The noncontact mode of cell handling is especially important when studies on nonadherent cells are performed, e.g., stem cells, yeast cells, or blood cells, as mechanical stress and surface interaction are minimized. The demonstrated acoustic trapping of cells and particles enables cell- or particle-based bioassays to be performed in a continuous flow format.

  • 7.
    Johansson, Linda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Enlund, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Katardjiev, Ilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wiklund, M
    Dept of Applied Physics, Albanova/KTH , Stockholm.
    Yantchev, Ventislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Surface acoustic wave-induced precise particle manipulation in a trapezoidal glass microfluidic channel2012In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 22, no 2, p. 025018-Article in journal (Refereed)
    Abstract [en]

    Surface acoustic wave (SAW) excitation of an acoustic field in a trapezoidal glass microfluidic channel for particle manipulation in continuous flow has been demonstrated. A unidirectional interdigital transducer (IDT) on a Y-cut Z-propagation lithium niobate (LiNbO3) substrate was used to excite a surface acoustic wave at approximately 35 MHz. An SU8 layer was used for adhesive bonding of the superstrate glass layer and the substrate piezoelectric layer. This work extends the use of SAWs for acoustic manipulation to also include glass channels in addition to prior work with mainly poly-di-methyl-siloxane channels. Efficient alignment of 1.9 mu m polystyrene particles to narrow nodal regions was successfully demonstrated. In addition, particle alignment with only one IDT active was realized. A finite element method simulation was used to visualize the acoustic field generated in the channel and the possibility of 2D alignment into small nodal regions was demonstrated.

  • 8.
    Johansson, Linda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Enlund, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Katardjiev, Ilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Yantchev, Ventsislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Surface acoustic wave induced particle manipulation in a PDMS channel: principle concepts for continuous flow applications2012In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 14, no 2, p. 279-289Article in journal (Refereed)
    Abstract [en]

    A device for acoustic particle manipulation in the40 MHz range for continuous-flow operation in a 50 μm wide PDMS channel has been evaluated. Unidirectionalinterdigital transducers on a Y-cut Z-propagation lithiumniobate wafer were used to excite a surface acoustic wavethat generated an acoustic standing wave inside the microfluidicchannel. It was shown that particle alignment nodeswith different inter-node spacing could be obtained,depending on device design and driving frequency. Theobserved inter-node spacing differed from the standard halfwavelengthinter-node spacing generally employed in bulkacoustic transducer excited resonant systems. This effectand the related issue of acoustic node positions relative thechannel walls, which is fundamental for most continuousflow particle manipulation operations in channels, wasevaluated in measurements and simulations. Specificapplications of particle separation and alignment wherethese systems can offer benefits relative state-of the artdesigns were identified.

  • 9.
    Johansson, Linda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Evander, Mikael
    Lilliehorn, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Almqvist, Monica
    Nilsson, Johan
    Laurell, Thomas
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Temperature and trapping characterization of an acoustic trap with miniaturized integrated transducers - towards in-trap temperature regulation2013In: Ultrasonics, ISSN 0041-624X, E-ISSN 1874-9968, Vol. 53, no 5, p. 1020-1032Article in journal (Refereed)
    Abstract [en]

    An acoustic trap with miniaturized integrated transducers (MITs) for applications in non-contact trapping of cells or particles in a microfluidic channel was characterized by measuring the temperature increase and trapping strength. The fluid temperature was measured by the fluorescent response of Rhodamine B in the microchannel. The trapping strength was measured by the area of a trapped particle cluster counter-balanced by the hydrodynamic force. One of the main objectives was to obtain quantitative values of the temperature in the fluidic channel to ensure safe handling of cells and proteins. Another objective was to evaluate the trapping-to-temperature efficiency for the trap as a function of drive frequency. Thirdly, trapping-to-temperature efficiency data enables identifying frequencies and voltage values to use for in-trap temperature regulation. It is envisioned that operation with only in-trap temperature regulation enables the realization of small, simple and fast temperature-controlled trap systems. The significance of potential gradients at the trap edges due to the finite size of the miniaturized transducers for the operation was emphasized and expressed analytically. The influence of the acoustic near field was evaluated in FEM-simulation and compared with a more ideal 1D standing wave. The working principle of the trap was examined by comparing measurements of impedance, temperature increase and trapping strength with impedance transfer calculations of fluid-reflector resonances and frequencies of high reflectance at the fluid-reflector boundary. The temperature increase was found to be moderate, 7 degrees C for a high trapping strength, at a fluid flow of 0.5 mm s(-1) for the optimal driving frequency. A fast temperature response with a fall time of 8 s and a rise time of 11 s was observed. The results emphasize the importance of selecting the proper drive frequency for long term handling of cells, as opposed to the more pragmatic way of selecting the frequency of the highest acoustic output. Trapping was demonstrated in a large interval between 9 and 11.5 MHz, while the main trapping peak displayed FWHM of 0.5 MHz. A large bandwidth enables a more robust manufacturing and operation while allowing the trapping platform to be used in applications where the fluid wavelength varies due to external variations in fluid temperature, density and pressure. 

  • 10.
    Johansson, Linda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thorslund, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Effective mixing of laminar flows at a density interface by an integrated ultrasonic transducer2009In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 9, no 2, p. 297-304Article in journal (Refereed)
    Abstract [en]

    An acoustic mixer for glass channel microfluidic systems is presented. An acoustic standing wave, perpendicular to the fluid flow, is generated by the excitation of a miniaturized piezoelectric transducer operated around 10 MHz. The transducer is fabricated into a planar printed circuit board structure, constituting the bottom channel wall, which makes the mixer simple to integrate with a wide selection of microfluidic channel designs. The mixing occurs at a fluid-fluid density interface due to the acoustic radiation force; an analytical expression is derived to qualitatively describe this phenomenon. Only a small density difference in the range of 2–5% is required to achieve 150–270% peak broadening of a fluorescent sample between sheath flows, which we use as a measure of the mixing efficiency. The mixing efficiency is measured with regard to its sensitivity to the density difference, the fluid velocity and the transducer driving frequency. Transducers at different positions along the microchannel make it possible to compare the mixing of straight versus diagonal flows across the transducer surface. We finally demonstrate enhanced chemical lysis of E. coli K12 cells in the device due to active fluid mixing.

  • 11.
    Johansson, Linda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Thorslund, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    On-chip fluorescence activated cell sorting by an integrated miniaturized ultrasonic transducer2009In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 81, no 13, p. 5188-5196Article in journal (Refereed)
    Abstract [en]

    An acoustic microfluidic system for miniaturized fluorescence-activated   cell sorting (mu FACS) is presented. By excitation of a miniaturized   piezoelectric transducer at 10 MHz in the microfluidic channel bottom, an acoustic standing wave is formed in the channel. The acoustic   radiation force acting on a density interface causes fluidic movement, and the particles or cells on either side of the fluid interface are displaced in a direction perpendicular to the standing wave direction. The small size of the transducer enables individual manipulation of   cells passing the transducer surface. At constant transducer activation   the system was shown to accomplish up to 700 mu m sideways displacement   of 10 mu m beads in a 1 mm wide channel. This is much larger than if   utilizing the acoustic radiation force acting directly on particles, where the limitation in maximum displacement is between a node and an antinode which at 10 MHz is 35 mu m. In the automatic sorting setup,   the system was demonstrated to successfully sort single cells of E-GFP expressing beta-cells.

  • 12.
    Johansson, Linda
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Nilsson, M
    Lilliehorn, T
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Almqvist, M
    Nilsson, J
    Laurell, T
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Temperature Evaluation of soft and hard PZT Transducers for Ultrasonic trapping in a microfluidic platform2005In: µTAS 2005, Boston, USA, 2005Conference paper (Refereed)
  • 13.
    Johansson, Linda
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Nilsson, M
    Lilliehorn, Tobias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Almqvist, M
    Nilsson, J
    Laurell, T
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    An Evaluation of the Temperature Increase from PZT Micro-Transducers for Acoustic Trapping2005In: Ultrasonics 2005, Rotterdam, Nederländerna, 2005Conference paper (Refereed)
  • 14.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Micro- and Nanomanipulation for Nanomanufacturing2014In: Encyclopedia of Nanotechnology / [ed] Bhushan, Bharat, springer , 2014, p. 1-17Chapter in book (Refereed)
  • 15.
    Johansson, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Snis, Niklas
    Piezomotor Uppsala AB.
    An ultrasonic motor for high-precision positioning2014Conference paper (Refereed)
  • 16. Laurell, T
    et al.
    Lilliehorn, Tobias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Almqvist, M
    Ressine, A
    Finnskog, D
    Nilsson, J
    Marko-Varga, G
    Nanotechnology – What’s in it for clinical chemistry?,2004In: IFBL’s 26 th Congress (International Federation of Biomedical Laboratory Science), Stockholm, Sweden, 2004Conference paper (Refereed)
  • 17.
    Lilliehorn,, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Blom, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Simu, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Johansson, S
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Nilsson, M
    Dept. of Electrical Measurements Lund Institute of Technology Lund, Sweden.
    Multilayer piezoelectric copolymer transducers2005In: Ultrasonics Symposium, 2005Conference paper (Other (popular science, discussion, etc.))
  • 18.
    Lilliehorn, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, Linda
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Nilsson, M.
    Almqvist, M
    Laurell, T.
    Nilsson, J
    Ultrasonic microbead trapping in microfluidic systems2004In: Actuator, Bremen, Germany, 2004Conference paper (Refereed)
  • 19.
    Lilliehorn, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, Linda
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Stepinski, Tadeusz
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Nilsson, M
    Almqvist, M
    Laurell, T
    Nilsson, J
    Array Transducer for Ultrasonic Manipulation of Particles2004In: MSW, Ystad, Sweden, 2004Conference paper (Other scientific)
  • 20.
    Lilliehorn, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Fabrication of multilayer 2-D ultrasonic transducer microarrays by green machining,2004In: J. Micromech. Microeng, Vol. 14, no 5, p. 702-709Article in journal (Refereed)
  • 21.
    Lilliehorn, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Nilsson, M
    Johansson, L
    Almqvist, S. U, M.
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Nilsson, J
    Laurell, T
    Bioassays on ultrasonically trapped microbead clusters in microfluidic systems2004In: MicroTAS, Malmö, Sweden, 2004Conference paper (Refereed)
  • 22.
    Lilliehorn, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Nilsson, M
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Almqvist, M
    Nilsson, J
    Laurell, T
    Dynamic arraying of microbeads for bioassays in microfluidic channels2005In: Sensors and Actuators B: Chemical, Vol. 106, no 2, p. 851-858Article in journal (Refereed)
  • 23.
    Lilliehorn, Tobias
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science. Technology, Department of Engineering Sciences, Signal Processing.
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science. Technology, Department of Engineering Sciences, Signal Processing.
    Nilsson, M
    Almqvist, M
    Stepinski, Tadeusz
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science. Technology, Department of Engineering Sciences, Signal Processing. Signals and systems.
    Laurell, T
    Nilsson, J
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science. Technology, Department of Engineering Sciences, Signal Processing.
    Trapping of microparticles in the near field of an ultrasonic transducer2005In: Ultrasonics, Vol. 43, no 5, p. 289-299Article in journal (Refereed)
  • 24. Nilsson, M
    et al.
    Almqvist, M.
    Nilsson, J
    Laurell, T
    Lilliehorn, Tobias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Ultrasonic beadtrapping for bioassays2004In: MSW, Ystad, Sweden,, 2004Conference paper (Refereed)
  • 25. Nilsson, M
    et al.
    Johansson, Linda
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Lilliehorn, Tobias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Lindvall, M
    Piskur, J
    Almqvist, M
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Laurell, T
    Nilsson, J
    Acoustic Trapping of Cells in a microfluidic format2005In: µTAS 2005, Boston, USA, 2005Conference paper (Refereed)
  • 26.
    Olofsson, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. PiezoMotor AB.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Analysis of the tribofilm formation on the friction drive surfaces of a piezoelectric motor2007In: ASME/STLE International Joint Tribology Conference, Parts A and B, 2007, p. 871-872Conference paper (Refereed)
  • 27.
    Olofsson, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. PiezoMotor AB.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Influence from humidity on the alumina friction drive system of an ultrasonic motor2009In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 42, no 10, p. 1467-1477Article in journal (Refereed)
    Abstract [en]

    Miniaturized ultrasonic motors, based on piezoelectric movement, are rapidly developing and the number of commercial applications is steadily growing. The details of the friction drive system of these motors still need systematic studies to fully utilize the potential of the technique. The friction drive system transfers the high frequency oscillatory movement from the stator to a drive rail. The friction force should be maximized and stabilized to achieve the best motor performance, while maintaining a low wear rate.

    The mating parts of a friction drive system typically consist of alumina which is selected due to its relatively low wear rate and relatively high coefficient of friction. With increasing relative humidity, the friction coefficients of alumina ceramics generally decrease.

    This work examines how water and humidity affect a friction drive system with respect to coefficient of friction and wear of the mating surfaces. Ball-on-disc experiments were used to evaluate the tribological properties. The worn surfaces were studied by scanning electron microscopy.

    The coefficient of friction was found to be relatively low but stable with water on the surface but higher and more fluctuating in dryer conditions. The character of the worn surfaces did not clearly correlate to the friction behaviour.

  • 28.
    Olofsson, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. PiezoMotor AB.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Influences from humidity on the friction drive system of a piezoelectric motor2008Conference paper (Refereed)
  • 29.
    Olofsson, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. PiezoMotor AB.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    The effect of grain size on the tribofilm formation on the alumina friction drive system of an ultrasonic motor2009In: ECOTRIB 09 / [ed] E. Ciulli, B. Piccigallo, R. Bassani, F. Franek, J. Vizintin, R. Crockett, Pisa: Edizioni ETS , 2009, p. 965-970Conference paper (Refereed)
  • 30.
    Olofsson, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Lindberg, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. PiezoMotor AB.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    On the role of tribofilm formation on the alumina drive components of an ultrasonic motor2009Conference paper (Refereed)
    Abstract [en]

    Ultrasonic motors typically have a friction drive system to transfer the movement. The miniaturized motor type investigated here has a friction drive system consisting of two drive pads that transfer the high frequency oscillating movement of two piezoelectric elements to a linear drive rail. The pads and rail consist of alumina.

    Fiction tests were carried out to investigate how the coefficient of friction between the drive pads and the drive rail depends on the number of strokes of the rail. It was found to initially increase with the number of strokes and then stabilize.

    Scanning electron microscopy studies of the friction drive surfaces show how a tribofilm forms and develops with the number of strokes. Interestingly, the smooth tribofilm surface gives a higher coefficient of friction than the original rougher surface. To further investigate the nature of the tribofilm. cross section samples were produced with a focused ion beam instrument. The tribofilms show different characters and appear to form gradually by agglomeration and sintering of wear debris. Transmission electron microscopy showed the tribofilm to be amorphous and partly nano-crystal line. This high resolution investigation also clearly demonstrated that the tribofilm bonds very well to the underlying alumina grains.

    The processes of friction increase and tribofilm build-up stabilize early compared to the lifetime of the motor.

  • 31.
    Olofsson, Johanna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Lindberg, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. PiezoMotor AB.
    Jacobson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    On the role of tribofilm formation on the alumina drive components of an ultrasonic motor2009In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 267, no 5-8, p. 1295-1300Article in journal (Refereed)
    Abstract [en]

    Ultrasonic motors typically have a friction drive system to transfer the movement. The miniaturized motor type investigated here has a friction drive system consisting of two drive pads that transfer the high frequency oscillating movement of two piezoelectric elements to a linear drive rail. The pads and rail consist of alumina.

    Fiction tests were carried out to investigate how the coefficient of friction between the drive pads and the drive rail depends on the number of strokes of the rail. It was found to initially increase with the number of strokes and then stabilize.

    Scanning electron microscopy studies of the friction drive surfaces show how a tribofilm forms and develops with the number of strokes. Interestingly, the smooth tribofilm surface gives a higher coefficient of friction than the original rougher surface. To further investigate the nature of the tribofilm. cross section samples were produced with a focused ion beam instrument. The tribofilms show different characters and appear to form gradually by agglomeration and sintering of wear debris. Transmission electron microscopy showed the tribofilm to be amorphous and partly nano-crystal line. This high resolution investigation also clearly demonstrated that the tribofilm bonds very well to the underlying alumina grains.

    The processes of friction increase and tribofilm build-up stabilize early compared to the lifetime of the motor.

  • 32.
    Olsson, Pontus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Carlbom, Ingrid
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nysjö, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Whole Hand Haptics2011In: Medicinteknikdagarna Oktober 11-12 2011, Linköping, Sweden, 2011Conference paper (Refereed)
    Abstract [en]

    Our sense of touch is in many ways the most sophisticated of our senses with receptors throughout the body. Unlike vision and hearing, haptics provides bi-directional communication between an individual and his/her environment. Yet, our sense of touch has been exploited for computer interfaces mostly in primitive ways, with both input and output limited to contact with a single point on a virtual object or to signal an event. But a single point of contact is often insufficient for exploration and manipulation: try to pick up a small object with only one finger! Current multi-point interaction devices are built using mechanical tendons, which are large and bulky and provide neither the stiffness nor the dynamic range required for object manipulation. We present a first generation of a haptic glove that acts as an external skeleton where the hand and finger joints are controlled by actuators that are integrated in the glove. This first prototype allows for six degrees of freedom (DOF) movement of the hand, and one DOF gripping with the thumb and index finger. The six DOF movements are accomplished with a commercial haptic arm, which allows us to simulate physical object properties such as weight, friction and inertia. The gripping force is controlled by the most compact high precision piezoelectric motor that is commercially available today, using a separate force sensor in a feed-back loop. The high stiffness of the motor in combination with a high dynamic speed range allows for delicate control of the gripping force. Combined with emerging 3D display technology, the haptic glove opens up exciting possibilities of co-located visio-haptic interaction more closely resembling real-world interaction.

  • 33.
    Olsson, Pontus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nysjö, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Carlbom, Ingrid
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Rendering stiffness with a prototype haptic glove actuated by an integrated piezoelectric motor2012In: Haptics: Perception, Devices, Mobility, and Communication: Part I, Springer Berlin/Heidelberg, 2012, p. 361-372Conference paper (Refereed)
  • 34.
    Olsson, Pontus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Nysjö, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Carlbom, Ingrid B.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Comparison of walking and traveling-wave piezoelectric motors as actuators in kinesthetic haptic devices2016In: IEEE Transactions on Haptics, ISSN 1939-1412, E-ISSN 2329-4051, Vol. 9, no 3, p. 427-431Article in journal (Refereed)
    Abstract [en]

    Piezoelectric motors offer an attractive alternative to electromagnetic actuators in portable haptic interfaces: they are compact, have a high force-to-volume ratio, and can operate with limited or no gearing. However, the choice of a piezoelectric motor type is not obvious due to differences in performance characteristics. We present our evaluation of two commercial, operationally different, piezoelectric motors acting as actuators in two kinesthetic haptic grippers, a walking quasi-static motor and a traveling wave ultrasonic motor. We evaluate each gripper's ability to display common virtual objects including springs, dampers, and rigid walls, and conclude that the walking quasi-static motor is superior at low velocities. However, for applications where high velocity is required, traveling wave ultrasonic motors are a better option.

  • 35.
    Simu, Urban
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Analysis of quasi-static and dynamic motion mechanisms for piezoelectric miniature robots2006In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 132, no 2, p. 632-642Article in journal (Refereed)
    Abstract [en]

    Piezoceramic actuators are often used when there is a need for high precision translation and are therefore of particular interest in the development of miniature robotic systems. In this paper the effect of miniaturisation on two dynamic and two quasi-static motion mechanisms has been experimentally evaluated using a miniature piezoceramic drive unit. The actuator design, comprising six piezoceramic multilayer bimorphs, and the rapid prototype process used to fabricate the monolithic multilayer structure, are described. Experiments show that for a mass of 1-10g, corresponding to the miniature robot considered, it is possible to use both dynamic and quasi-static motion mechanisms. With the present drive unit at low loads, the dynamic motion mechanisms are less demanding and work closer to the ideal case than quasi-static motion mechanisms. At higher loads the opposite will in general be true. Artefacts due to vibrations and bouncing in the vertical direction are the main reason for non-ideal behaviour when a small movable mass is used. In particular, movements generated by mechanisms utilizing a vertical velocity component are sensitive to a low mass. The design parameters to avoid or reduce these artefacts are identified and discussed.

  • 36.
    Snis, Niklas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Edqvist, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Simu, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Monolithic fabrication of multilayer P(VDF-TrFE) cantilevers2008In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 144, no 2, p. 314-320Article in journal (Refereed)
    Abstract [en]

    When operating a piezoelectric actuator the use of multilayers has for a long time proven to be a good solution to maintain a high electric field at a reduced applied voltage. The piezoelectric copolymer polyvinylidene-trifluoroethylene P(VDF-TrFE) has rather low piezoelectric constant compared to piezoceramics but it can withstand much higher electric fields. As the copolymer can be spin coated the individual layer thickness of the multilayer can easily be reduced to a few m and rather large strains can be achieved at a moderate voltage. Here a monolithic fabrication technique for producing P(VDF-TrFE) actuators, without any lamination or adhesive layers, is presented. To fabricate the multilayer successive spin coating of the piezoelectric polymer polyvinylidene-trifluoroethylene P(VDF-TrFE) and electrode evaporation on a substrate was performed. Four different substrate materials were coated with a multilayer stack of 6 active P(VDF-TrFE) layers and 7 aluminum electrodes. The monolithic multilayer structures with patterned electrodes were diced by a cutting saw to produce unimorph cantilevers. No delamination or dissolution could be observed between adjacent copolymer layers. The cantilevers were evaluated in terms of static and resonant deflection and the Q-factor was estimated from the frequency spectra. A discussion regarding the influence of the Q-factor on the fabrication process tolerance is given. The different substrate materials used was stainless steel, flexible printed circuit board (FPC), polycarbonate and aluminum. The Q-factor varied from 30 for the polycarbonate to 83 for the stainless steel. These results provide guidelines for the material choices of a forthcoming locomotion module to be used in the 3 mm 3 mm 3 mm I-SWARM robots. The FPC substrate showed to have the best compatibility to the fabrication processes and the most suitable Q-value of 42. This together with the high deflections makes the FPC the preferred substrate materials the future actuators for the I-SWARM locomotion module. 2008 Elsevier B.V. All rights reserved.

  • 37.
    Snis, Niklas
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Johansson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    A piezoelectric disc-shaped motor using a quasi-static walking mechanism2005In: Journal of Micromechanics and Microengineering, Vol. 15, p. 2230-2234Article in journal (Refereed)
  • 38.
    Thornell, Greger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Laurell, T
    Nilsson, J
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Desktop microfabrication: initial experiments with a piezoceramic1999In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 9, no 4, p. 434-437Article in journal (Refereed)
    Abstract [en]

    A method for building microstructures from a suspension of micrometre-sized piezoelectric particles by depositing droplets on top of droplets and promoting drying is devised. A micromachined dispensing unit similar to a drop-on-demand inkjet-printer head is used. The relation of the vertical building rate to the ejection frequency and the substrate temperature is established, and a mechanism explaining the tubular structures built is proposed.

  • 39.
    Yantchev, Ventsislav
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Enlund, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Katardjiev, Ilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Johansson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Johansson, Linda
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Interface acoustic wave based manipulation of sub-micrometer particles in microfluidic channels2009In: Proceedings. 2009 Inernational IEEE Ultrasonic Symposium, 2009Conference paper (Refereed)
    Abstract [en]

    The work in question addresses the issue of continuous flow particle manipulation in liquid media with particularemphasis on particles with micron and sub-micron dimensions.The subject is of significant relevance for a range of biotechnological applications and in particular for lab-on-chip ones.Particle manipulation utilizing Interface Acoustic Waves (IAW)is proposed for the first time. Manipulation of submicron sized particles is successfully demonstrated in a streaming free regime.

1 - 39 of 39
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