Devices and Methods for Driving a Rotary Platform

Abstract

One example device includes a rotor platform that rotates about an axis of rotation. The device also includes a ring magnet mounted to the rotor platform to provide a rotor-platform magnetic field. The device also includes a stator platform that includes a planar mounting surface. The device also includes a plurality of conductive structures disposed along the planar mounting surface. The conductive structures remain within a predetermined distance to the ring magnet in response to rotation of the rotor platform about the axis of rotation. The conductive structures are electrically coupled to define an electrically conductive path that at least partially overlaps the ring magnet. The device also includes circuitry that causes an electrical current to flow through the conductive path. The electrical current generates a stator-platform magnetic field that interacts with the rotor-platform magnetic field such that the rotor platform rotates about the axis of rotation.

1 - 13 . (canceled) 
     
     
         14 . A method for rotating a first platform of a device relative to a second platform of the device and about an axis of rotation of the first platform, wherein the first platform remains within a predetermined distance to the second platform in response to rotation of the first platform about the axis of rotation, the method comprising:
 causing an electrical current to flow through an electrically conductive path included in the second platform and extending around the axis of rotation of the first platform, wherein the electrically conductive path is defined by a plurality of conductive structures in a substantially coplanar arrangement, wherein the electrical current generates a second-platform magnetic field that interacts with a first-platform magnetic field such that the first platform rotates about the axis of rotation; and   modulating the electrical current to adjust an orientation of the first platform about the axis of rotation to achieve a target orientation.   
     
     
         15 . The method of  claim 14 , further comprising:
 modulating the electrical current to adjust a characteristic of the rotation of the first platform, wherein the characteristic comprises a direction or a rate of the rotation.   
     
     
         16 . The method of  claim 14 , further comprising:
 obtaining output of a magnetic field sensor included in the second platform and positioned between two particular adjacent conductive structures of the plurality of conductive structures, wherein the plurality of conductive structures includes a plurality of spaced-apart conductive structures that are spaced apart by a substantially uniform distance, and wherein the two particular adjacent conductive structures are spaced apart by a greater distance than the substantially uniform distance; and   determining an orientation of the first platform about the axis of rotation based on the output of the magnetic field sensor.   
     
     
         17 - 20 . (canceled)