The control of self-propelled microjets inside a microchannel with time-varying flow rates

I.S.M. Khalil, Veronika Magdanz, Samuel Sanchez, Oliver S. Schmidt, Sarthak Misra

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    Abstract

    We demonstrate the closed-loop motion control of self-propelled microjets inside a fluidic microchannel. The motion control of the microjets is achieved in hydrogen peroxide solution with time-varying flow rates, under the influence of the controlled magnetic fields and the self-propulsion force. Magnetic dipole moment of the microjets is characterized using the U-turn and the rotating field techniques. The characterized magnetic dipole moment has an average of 1.4 × 10−13 A.m2 at magnetic field, linear velocity, and boundary frequency of 2 mT, 100 μm/s, and 25 rad/s, respectively. We implement a closed-loop control system that is based on the characterized magnetic dipole moment of the mi- crojets. This closed-loop control system positions the microjets by directing the magnetic field lines toward the reference position. Experiments are done using a magnetic system and a fluidic microchannel with a width of 500 μm. In the absence of a fluid flow, our control system positions the microjets at an average velocity and within an average region-of-convergence (ROC) of 119 μm/s and 390 μm, respectively. As a representative case, we observe that our control system positions the microjets at an average velocity and within an average ROC of 90 μm/s and 600 μm and 120 μm/s and 600 μm when a flow rate of 2.5 μl/min is applied against and along the direction of the microjets, respectively. Furthermore, the average velocity and ROC are determined throughout the flow range (0 to 7.5 μl/min) to characterize the motion of the microjets inside the microchannel.
    Original languageUndefined
    Pages (from-to)49-58
    Number of pages10
    JournalIEEE transactions on robotics
    Volume30
    Issue number1
    DOIs
    Publication statusPublished - Feb 2014

    Keywords

    • time-varying flow
    • microjets
    • microrobots
    • self-propulsion
    • IR-87539
    • Magnetic torque
    • Motion Control
    • Microchannel
    • METIS-300105
    • EWI-23862

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