Attracting Conductive Nonmagnetic Objects With Rotating Magnetic Dipole Fields

Recent research has shown that eddy currents induced by rotating magnetic dipole fields can produce forces and torques useful for dexterous manipulation of conductive nonmagnetic objects. This control paradigm shows promise for application in the remediation of space debris. However, the resulting force from each field source always includes a repulsive component, suggesting that the object should be surrounded by field sources to some degree to ensure the object does not leave the dexterous workspace during manipulation. In this letter, we describe the ability of multiple field sources working together in a coordinated fashion to attract conductive nonmagnetic objects that are not surrounded, reminiscent of a tractor beam. This enables an object to be pulled into a dexterous manipulation workspace. We explicitly describe the nominal attractive force on spherical objects, serving as an approximation for other object geometries, as a function of the properties of the object and the field-generation system. We perform experimental verification using a water-based microgravity simulator.