Over the past decade, researchers have made significant advances on using magnets to precisely move objects without any physical contact. However, the objects are specially designed to be made mostly of ferromagnetic material so that they can be moved by magnets. But what if it were possible to use magnets to manipulate metal objects that contain no magnetic material at all, which is common in many engineered devices? It is well known that moving magnets create electrical fields that, in turn, can generate forces in metal objects through the generation of eddy currents. The project explores how these forces can be used to control the movement of such objects, enabling manipulation in microgravity and undersea, and enabling new tools for scientific research.
This project methodically characterizes the physics of magnetic manipulation of nonmagnetic-but-conductive spheres (solid and thin walled). For the time-varying magnetic fields used to generate eddy currents in the spheres, rotating magnetic dipole fields are used, which are generated by unique electromagnetic and permanent-magnet hardware platforms developed by the Principal Investigator with prior NSF support. The project characterizes eddy-current-based manipulation as a robotic-manipulation problem, in order to determine how the number and placement of the dipole actuation sources affects manipulability. The project tests the hypothesis that a sphere can be manipulated with limited prior knowledge by learning the model?s parameters while using guarded actions to avoid loss of control authority. This joint learning and control problem is formulated as an information-theoretic, active-learning problem to find informative samples for learning, subject to unknown manipulation constraints imposed by the electromagnetic physics of the system. Finally, the project includes a feasibility study in the practical application of this phenomenon.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
