Closed-path linear motor

• US 6,713,902 B2
• Filed: 06/06/2002
• Issued: 03/30/2004
• Est. Priority Date: 02/26/1998
• Status: Expired due to Term

• Current Assignee: Rockwell Automation, Inc.
• Original Assignee: Anorad Corporation (Rockwell Automation, Inc.)
• Inventors: Chitayat, Anwar
• Primary Examiner(s): Dougherty, Thomas M.
• Assistant Examiner(s): JONES, JUDSON
• Application Number:
  US10/163,664
• Publication Number:
  US 20020149272A1
• Time in Patent Office: 663 Days
• Field of Search: 310/12, 310/13, 310/14, 318/135
• US Class Current: 310/12.16
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: H02K 11/00 Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection casings, enclosures or supports H02K5/00
• CPC Class Codes: H02K 11/22 Optical devices
• CPC Class Codes: H02K 41/02 Linear motors; Sectional motors
• CPC Class Codes: H02K 41/03 Synchronous motors; Motors moving step by step; Reluctance motors H02K41/035 takes precedence
• CPC Class Codes: H02P 25/06 Linear motors

Abstract

A system and method for a linear motor for driving a plurality of stages along a path are provided. The linear motor system includes a plurality of armature windings arranged to form a path, such as may be straight, curved, opened or closed. The stages include motor magnets that provide a magnet field. An encoder sensor is connected for movement with the stages so as to sense relative movement between the stages and the path. The encoder sensor further is operative to provide an encoder signal having an electrical characteristic indicative of relative movement between the stages and the path.

Claims

1. A linear motor system comprising:

a linear path for supporting and guiding a plurality of stages, the linear path having a plurality of armature windings thereon;

a plurality of switches, a subset of the switches being connected with respective armature windings; and

a plurality of stages, a subset of the stages having at least one switching magnet and at least one motor magnet on at least one stage, wherein the subset of switches respectively close when under the influence of the at least one switching magnet such that power can be applied to the respective armature windings to interact with the at least one motor magnet and effect movement of the at least one stage along the path.

2. The system of claim 1, wherein the subset of the plurality of stages corresponds with a respective one of a plurality of pendant arms, the plurality of pendant arms having at least one encoder magnet and at least one switching magnet thereon.

3. The system of claim 1, wherein the subset of the plurality of stages corresponds with a respective one of a plurality of rails, the plurality of rails having at least one encoder sensor and at least one switching sensor thereon.

4. The system of claim 1, wherein the subset of the plurality of stages is separately controlled by a motor controller.

5. The system of claim 1, wherein the path contains closed-loop control regions and open-loop control regions.

6. The system of claim 1, further comprising a memory for receiving command motion information.

7. The system of claim 1, the path comprising a plurality of path modules arranged in an end-to-end manner.

8. The system of claim 1, the path being shaped in a racetrack pattern.

9. The system of claim 1, the path being a multilevel path.

10. The system of claim 9, the multilevel path including a down spiral aside a down and up spiral.

11. The system of claim 1, the path being shaped in a Moebius band pattern.

12. Manufacturing equipment employing the linear motor system of claim 1.

13. A method for driving a plurality of stages along a linear motor path comprising:

providing independent application of armature power to at least are stage of a subset of the plurality of stages from a motor controller; and

providing independent armature switching and independent position communication from at least one stage a subset of the plurality of stages to the motor controller.

14. The method of claim 13, further comprising generating a programmed phase sequence for control at least one of the plurality of stages if the position communication is not received by the motor controller.

15. The method of claim 13, further comprising providing path switching to direct at least one of the plurality of stages flexibly along different paths.

16. The method of claim 13, further comprising receiving command motion information and continuously comparing the command motion information with a computer until a commanded condition is attained.

17. A system for driving a plurality of stages along a linear motor path comprising:

means for providing independent application of armature power to a subset of the plurality of stages from a motor controller; and

means for providing independent armature switching and independent position communication from a subset of the plurality of stages to the motor controller.