High-resolution positioning device

• US 9,479,040 B2
• Filed: 04/27/2012
• Issued: 10/25/2016
• Est. Priority Date: 04/29/2011
• Status: Active Grant

• Current Assignee: Physik Instrumente (PI) GmbH & Co. KG
• Original Assignee: Physik Instrumente (PI) GmbH & Co. KG
• Inventors: Mohr, Hans-Ulrich, Gl, Rainer, Schffel, Christoph, Katzschmann, Michael, Walenda, Carolin, Rudolf, Christian
• Primary Examiner(s): Kenerly, Terrance
• Assistant Examiner(s): Elnakib, Ahmed
• Application Number:
  US14/112,315
• Publication Number:
  US 20140077627A1
• Time in Patent Office: 1,642 Days
• Field of Search: 310/12.06, 310/12.05, 310/12.19, 310/68.B, 310/68.E, 310/90.5, 250/442
• US Class Current: 1/1
• CPC Class Codes: H02K 2201/18 Machines moving with multiple degrees of freedom
• CPC Class Codes: H02K 41/02 Linear motors; Sectional motors
• CPC Class Codes: H02K 41/031 of the permanent magnet type
• CPC Class Codes: H02K 7/09 with magnetic bearings

Abstract

A high-resolution positioning device has a stator and a rotor, a coil array, arranged on the stator, and having at least three groups of flat coils, wherein each group has at least two single coils and the coil array encloses a free space on the stator, also having permanent magnetically-excited circuits that are situated on, against or in the rotor and form a magnet array which likewise encloses a free space, wherein the free spaces accommodate a position measuring system which has a measuring head having sensors, and an area scale. The device is in the form of a freely suspended, magnetically controlled six-dimensional drive, wherein the measuring head is situated in the coil array free space and the area scale is situated in the magnet array free space, and the rotor is free of drive-related electrical or electronic and, in this regard, live parts.

Claims

1. A high-resolution positioning device having a stator and a rotor, a coil array, arranged on the stator, having at least three groups of flat coils, wherein each group has at least two single coils as a coil pair and the coil array encloses a free space on the stator, furthermore having permanent magnetically-excited circuits that are situated on, against or in the rotor and form a magnet array which likewise encloses a free space, wherein the free spaces accommodate a position measuring system which has a measuring head with sensors and an area scale,

characterized in that

the positioning device is formed as a freely suspended, magnetically controlled six-dimensional drive, wherein with a corresponding energization and commutation of one coil pair of the coil array, horizontal and vertical forces as well as torques can each be imposed on the rotor by the magnetic interaction in the associated row of the magnet array, and the vertical forces serve the purpose of carrying the rotor weight and the positioning of the rotor, and the permanent-magnetically excited circuits are each composed of a Halbach array comprising a plurality of segments, and the measuring head is situated in the coil array free space and the area scale in the magnet array free space, and the rotor is free of drive-related electrical or electronic and, in this regard, live parts, and

for weight compensating the rotor, ferromagnetic plates covering the rotor and travel range are coupled to the stator, and permanent magnetically-excited magnet circuits to the rotor, and an air gap distance is present between the ferromagnetic plates and the permanent magnetically-excited magnet circuits, wherein the ferromagnetic plates cover the pole faces of the permanent magnetically-excited magnet circuits preferably completely in each position of the rotor.

2. The positioning device according to claim 1,

characterized in that

the measuring head has an area shape adapted to the coil array free space and utilizing the available space.

3. The positioning device according to claim 1,

characterized in that

the measuring head comprises optical incremental sensors as well as capacitive sensors.

4. The positioning device according to claim 3,

characterized in that

the capacitive sensors are arranged in the area edge region and at least one optical sensor is arranged in the center of the measuring head.

5. The positioning device according to claim 3,

characterized in that

the capacitive sensors are each composed of a pair of sensors which detect the respective distance from the surface of the area scale in order to detect angular positions and movements in the z direction therefrom.

6. The positioning device according to claim 3,

characterized in that

the optical sensors, in conjunction with the area scale, detect movements in the x and y directions and rotational or yaw movements about the z direction.

7. The positioning device according to claim 1,

characterized in that

the measuring head has the shape of a triangle and

the coil array comprises three coil pairs which are arranged in a triangular shape and preferably offset from each other in each case by 120°

, and the magnet array comprises three magnet rows wherein the rows of ma nets are each situated centered to a coil pair when the rotor is in the center position relative the stator.

8. The positioning device according to claim 1,

characterized in that

the respective coil group is realized as a structural unit having cooling tubes and forming a sandwich arrangement and

the respective coil group comprises an enclosure with means for supplying or discharging a cooling medium.

9. The positioning device according to claim 1,

characterized in that

the rotor is configured as a supporting body having hollow spaces for receiving the magnet array.

10. The positioning device according to claim 1,

characterized in that

reference sensors are provided for a defined start or rest position for the rotor relative to the stator.

11. The positioning device according to claim 1,

characterized in that

the coil array is embedded in the stator and is essentially flush with the stator surface.

12. A high-resolution positioning device having a stator and a rotor, a coil array, arranged on the stator, having at least three groups of flat coils, wherein each group has at least two single coils as a coil pair and the coil array encloses a free space on the stator, furthermore having permanent magnetically-excited circuits that are situated on, against or in the rotor and form a magnet array which likewise encloses a free space, wherein the free spaces accommodate a position measuring system which has a measuring head with sensors and an area scale,

characterized in that

the positioning device is formed as a freely suspended, magnetically controlled six-dimensional drive, wherein with a corresponding energization and commutation of one coil pair of the coil array, horizontal and vertical forces as well as torques can each be imposed on the rotor by the magnetic interaction in the associated row of the magnet array, and the vertical forces serve the purpose of carrying the rotor weight and the positioning of the rotor, and the permanent-magnetically excited circuits are each composed of a Halbach array comprising a plurality of segments, and the measuring head is situated in the coil array free space and the area scale in the magnet array free space, and the rotor is free of drive-related electrical or electronic and, in this regard, live parts, and

for weight compensating the rotor, ferromagnetic plates covering the rotor and travel range are coupled to the stator and electromagnets interacting with the ferromagnetic plates are provided to be coupled to the rotor, wherein an air gap distance is present between the ferromagnetic plates and the electromagnets, and the ferromagnetic plates cover the pole faces of the electromagnets preferably completely in each position of the rotor.

13. The positioning device according to claim 12,

characterized in that

the measuring head has an area shape adapted to the coil array free space and utilizing the available space.

14. The positioning device according to claim 12,

characterized in that

the measuring head comprises optical incremental sensors as well as capacitive sensors.

15. The positioning device according to claim 14,

characterized in that

the capacitive sensors are arranged in the area edge region and at least one optical sensor is arranged in the center of the measuring head.

16. The positioning device according to claim 14,

characterized in that

the capacitive sensors are each composed of a pair of sensors which detect the respective distance from the surface of the area scale in order to detect angular positions and movements in the z direction therefrom.

17. The positioning device according to claim 14,

characterized in that

the optical sensors, in conjunction with the area scale, detect movements in the x and y directions and rotational or yaw movements about the z direction.

18. The positioning device according to claim 12,

characterized in that

the measuring head has the shape of a triangle and

the coil array comprises three coil pairs which are arranged in a triangular shape and preferably offset from each other in each case by 120°

, and the magnet array comprises three magnet rows, wherein the rows of magnets are each situated centered to a coil pair when the rotor is in the center position relative the stator.

19. The positioning device according to claim 12,

characterized in that

the respective coil group is realized as a structural unit having cooling tubes and forming a sandwich arrangement and

the respective coil group comprises an enclosure with means for supplying or discharging a cooling medium.

20. The positioning device according to claim 12,

characterized in that

the rotor is configured as a supporting body having hollow spaces for receiving the magnet array.

21. The positioning device according to claim 12,

characterized in that

reference sensors are provided for a defined start or rest position for the rotor relative to the stator.

22. The positioning device according to claim 12,

characterized in that

the coil array is embedded in the stator and is essentially flush with the stator surface.