Device for supporting and linearly moving an object

A device for supporting and linearly moving an object, said device comprising:

• a stationary body having a cylindrical internal bore;
• a movable member having an outer peripheral portion and coupled to the object and situated within the cylindrical internal bore of the stationary body to be axially movable in an axial direction in the cylindrical internal bore of the stationary body;
• yokes fixed on the inner peripheral portion of the stationary body at predetermined intervals in the circumferential direction of the inner peripheral portion of the stationary body, such that magnetic pole faces of the yokes are directed to the movable member;
• bias coil mounted on the yokes, for being supplied with a predetermined bias current;
• control coils mounted on the yokes, for being supplied with a predetermined control current;
• projecting magnetic poles formed on the outer peripheral portion of the movable member, such that projecting faces of the projecting magnetic poles, which are opposed to the magnetic pole faces of the yokes, are arranged at predetermined intervals in a circumferential direction of the outer peripheral portion of the movable member and extend in the axial direction of the movable member;
• position detection faces formed on the outer peripheral portion of the movable member along a circumference of the outer peripheral portion of the movable member between the projecting magnetic poles, the position detection faces extending axially;
• position detectors, disposed on the stationary body and opposed to the position detection faces, for detecting positions of the position detection faces, thereby detecting a distance between the movable member and a predetermined position in a non-contact manner;
• levitation means for controlling an electric current to be supplied to the coils in relation to outputs of the position detectors, thereby electromagnetically levitating the movable member at a predetermined position in the cylindrical internal bore;
• and
• vibration damping means for controlling an electric current to be supplied to the coils in relation to a sum signal of at least two of the outputs of the position detectors, said vibration damping means including means for superimposing the control current on the bias current, and supplying the superimposed current to the bias coil.

A device for supporting and linearly moving an object, said device comprising:

• a stationary body having a cylindrical internal bore;
• a movable member coupled to the object and situated within the cylindrical internal bore of the stationary body to be axially movable in the cylindrical internal bore of the stationary body;
• yokes fixed on the inner peripheral portion of the stationary body at predetermined intervals in the circumferential direction of the inner peripheral portion of the stationary body, such that magnetic pole faces of the yokes are directed to the movable member;
• coils mounted on the yokes;
• projecting magnetic poles formed on the outer peripheral portion of the movable member, such that projecting faces of the projecting magnetic poles, which are opposed to the magnetic pole faces of the yokes, are arranged at predetermined intervals in the circumferential direction of the outer peripheral portion of the movable member and extend in the axial direction of the movable member;
• position detection faces formed on the outer peripheral portion of the movable member along the circumference of the outer peripheral portion of the movable member between the projecting magnetic poles, the position detection faces extending axially;
• position detectors, disposed on the stationary body and opposed to the position detection faces, for detecting the positions of the position detection faces, thereby detecting the distance between the movable member and a predetermined position in a non-contact manner;
• levitation means for controlling an electric current to be supplied to the coils on the basis of outputs of the position detectors, thereby electromagnetically levitating the movable member at a predetermined position in the cylindrical internal bore.
• a rotation control yoke situated such that a magnetic pole face thereof is directed to both circumferential end portions of at least one of the projecting magnetic poles formed on the movable member;
• a control coil mounted on the rotation control yoke;
• data acquisition means for acquiring rotational displacement data of the movable member on the basis of a sum signal of at least two of outputs from the position detectors;
• and
• vibration damping means for activating the control coil on the basis of a rotational displacement amount represented by the rotational displacement data acquired by the acquiring means, thereby damping the vibration of the movable member about its axis.

A device for supporting and linearly moving an object, said device comprising:

• a stationary body having a cylindrical internal bore surface;
• a movable member having an outer peripheral surface and coupled to the object and situated within the cylindrical internal bore of the stationary body to be axially movable in the cylindrical internal bore of the stationary body;
• electromagnets arranged between the inner peripheral surface of the stationary body and the outer peripheral surface of the movable member at two or more axial points, said electromagnets electromagnetically levitating the movable member in relation to the stationary body;
• radial position detection means for detecting a radial position of the movable member;
• magnet control means for controlling a magnetic force of the electromagnets in relation to an output from the radial position detection means;
• axial movement amount detection means for detecting an axial movement amount of the movable member;
• electromagnetic force generating means, for applying an axial driving force to the movable member;
• and
• control parameter adjusting means for adjusting a control parameter of the magnet control means in accordance with an output from the axial movement amount detection means, said control parameter adjusting means including level adjusting means for adjusting a level of a constant excitation current applied to the electromagnets, so as to meet force equilibrium conditions for total forces of the electromagnets and non-interference conditions for mutual non-interference between center-of-gravity movement and rotational movement both the center of gravity of the movable member,
• control model updating means for updating a magnetic support system model imagined in relation to the electromagnets, in accordance with the output from the axial movement amount detection means;
• and
• compensation parameter updating means for updating a compensation parameter of stabilizing the magnetic support system, in relation to the result of the control model updating means.

A device for supporting and linearly moving an object, said device comprising:

• a stationary body having a cylindrical internal bore;
• a movable member coupled to the object and situated within the cylindrical internal bore of the stationary body to be axially movable in the cylindrical internal bore of the stationary body;
• axial position detection means for detecting the axial position of the movable member in a non-contact manner;
• a magnetic bearing device comprising electromagnets arranged between the inner peripheral surface of the stationary body and the outer peripheral surface of the movable member at predetermined intervals in the circumferential direction of the stationary body and the movable member, said electromagnets electromagnetically levitating the movable member in relation to the stationary body;
• electromagnetic force generating means, for applying an axial driving force to the movable member, said electromagnetic force generating means including a voice coil motor having a driving coil;
• a data table storing correction data for correcting at least an attitude error of the movable member over the entire axial movement range of the movable member;
• read-out means for reading out, from the data table, the correction data corresponding to the axial position represented by the axial position data acquired by the axial position detection means;
• and
• attitude adjusting means for adjusting at least the attitude of the movable member by delivering the correction data read out by the read-out means to the magnetic bearing device.