A 4x4 array of coils with iron cores, each with a controllable current, creates a magnetic field. An iron ball is revolving on a flat surface placed on top of the coils in response to this magnetic field. A real-time mesurement of the position of the ball is realized using a pressure sensitive resistive foil on top of the surface. These measurements are periodically brought to a PC through a data acquisition PCI card and processed in real time by Simulink. Commanded values of coil currents are produced by a feedback controller running in Simulink.
<p>Currently, only a single object (ball) can be manipulated since the sensoric foil cannot work with more than one ball. We are investigating other planar sensor principles, considering capacitive, magnetic and other priciples. Of course, the last resort are real-time computer vision techniques.
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The presented system serves as a benchmark platform for the algorithmic task of "distributed planar manipulation by shaping force fields through an actuator array". Another instance, perhaps a bit more practically relevant, is (micro)manipulation with (electrically neutral) particles by shaping an electric field through an array of electrodes (so-called dielectrophoresis), which is motivated by the needs in bioanalytical instrumentation. See some videos in the same channel.
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<bdo lang="en" dir="ltr"><a href="//commons.wikimedia.org/wiki/Commons:YouTube_files" title="Commons:YouTube files">YouTube</a>: <a rel="nofollow" class="external text" href="https://www.youtube.com/watch?v=kKXPDXM1ItI"><bdi lang="">Steering an iron ball along a circular path by shaping the magnetic field using an array of coils</bdi></a> – View/save archived versions on <a rel="nofollow" class="external text" href="https://web.archive.org/web/*/https://www.youtube.com/watch?v=kKXPDXM1ItI">archive.org</a> and <a rel="nofollow" class="external text" href="https://archive.today/https://www.youtube.com/watch?v=kKXPDXM1ItI">archive.today</a></bdo>