Wireless control and selection of forces and torques--towards wireless engines

Powering and manipulating translational and rotational motions of objects wirelessly, and controlling several objects independently is of significant importance in numerous fields such as robotics, medicine, biology, fluid dynamics, optics. We propose a method based on coupled LC resonators, to control objects selectively by steering the frequency of an external magnetic field. This concept does not need any magnetic materials and it brings a rich variety of features concerning forces and torques. We theoretically and experimentally show that the forces can be enhanced by the interaction of resonators and that both direction and magnitude of forces can be controlled by the frequency of the applied external magnetic field. Moreover, we demonstrate interesting rotational effects, such as bi-directionally controllable torques, controllable stable orientations, and spinning, which leads to a wirelessly powered motor.