Displacement devices and methods for fabrication, use and control of same

Patent metadata

Field	Value
Publication number	US-10116195-B2
Application number	US-201615365767-A
Country	US
Kind code	B2
Filing date	Nov 30, 2016
Priority date	May 30, 2014
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A displacement device comprise a stator having a plurality of electrically conductive coils shaped to provide: a first plurality of coil traces generally elongated in a stator-x direction and distributed over at least a first portion of a first layer; a second plurality of coil traces generally elongated in a stator-y direction and distributed over at least a second portion of a second layer. The first and second portions of the first and second layers overlapping one another in a stator-z direction. The displacement device also comprises a moveable stage having one or more magnet arrays. The moveable stage is moveable relative to the stator within a two-dimensional working region. The one or more magnet arrays include a first magnet array comprising a plurality of first magnetization segments, each having a corresponding first magnetization direction. The displacement device comprises one or more amplifiers connected to drive a plurality of currents in the plurality of electrically conductive coils; and a controller configured to control the currents driven by the one or more amplifiers and to thereby cause the moveable stage to track a desired position, (xr,yr), within the working region.

First claim

What is claimed is:

1. A displacement device comprising:
a stator comprising a plurality of electrically conductive coils, the plurality of electrically conductive coils shaped to provide:
a first plurality of coil traces generally elongated in a stator-x direction and distributed over at least a first portion of a first layer;
a second plurality of coil traces generally elongated in a stator-y direction and distributed over at least a second portion of a second layer, the stator-y direction non-parallel to the stator-x direction;
the first and second portions of the first and second layers overlapping one another in a stator-z direction, the stator-z direction generally orthogonal to both the stator-x direction and the stator-y direction;

a moveable stage comprising one or more magnet arrays, the moveable stage moveable relative to the stator within a two-dimensional working region, the one or more magnet arrays comprising a first magnet array, the first magnet array comprising a plurality of first magnetization segments, each first magnetization segment having a corresponding first magnetization direction;
one or more amplifiers connected to drive a plurality of currents in the plurality of electrically conductive coils;
a controller connected to deliver signals to the one or more amplifiers and configured, by using such signals, to control the currents driven by the one or more amplifiers and to thereby cause the moveable stage to track a desired position, (x r ,y r ), within the working region, where x r is a desired position of the moveable stage in the stator-x direction in the working region and y r is a desired position of the moveable stage in the stator-y direction in the working region;

wherein:
the controller is configured to control the currents driven by the one or more amplifiers to drive first currents, i x , in at least some of the first plurality of coil traces and to drive second currents, i y , in at least some of the second plurality of coil traces;
the first currents, i x , comprise a plurality of first current phases, i kx , each first current phase, i kx , driven into a corresponding one of the at least some of the first plurality of coil traces and phase-adjacent first current phases driven into spatially adjacent ones of the at least some of the first plurality of coil traces, where:
k is an integer from 0 to n p −1 representing a first phase index; and
n p is a number greater than or equal to two of different effective phases in the first currents, i x ;
each first current phase, i kx , is determined based on a function F(y r ), where F(y r ) is a spatially periodic function of y r in the stator-y direction over the working region, with a first spatial period, λ 1 ;
each first current phase, i kx , in a particular one of the at least some of the first plurality of coil traces is out of phase, as a function of y r , with one or more phase-adjacent first current phases in one or more spatially adjacent ones of the at least some of the first plurality of coil traces by a first spatial phase difference

λ
1

2
⁢

n
p

;

the second currents, i y , comprise a plurality of second current phases, i jy , each second current phase, i jy , driven into a corresponding one of the at least some of the second plurality of coil traces and phase-adjacent second current phases driven into spatially adjacent ones of the at least some of the second plurality of coil traces, where:
j is an integer from 0 to m p −1 representing a second phase index; and
m p is a number greater than or equal to two of different effective phases in the second currents, i y ;
each second current phase, i jy , is determined based on a function G(x r ), where G(x r ) is a spatially periodic function of x r in the stator-x direction over the working region, with a second spatial period, λ 2 ; and
each second current phase, i jy , in a particular one of the at least some of the second plurality of coil traces is out of phase, as a function of x r , with one or more phase-adjacent second current phases in one or more spatially adjacent ones of the at least some of the second plurality of coil traces by a second spatial phase difference

λ
2

2
⁢

m
p

.

2. A displacement device according to claim 1 wherein F(y r ) and G(x r ) are each sinusoidal functions.

3. A displacement device according to claim 1 wherein the controller is configured to determine each first current phase, i kx , according to

i
kx

=

A
kx

⁢

sin
⁡

(

y
r

λ
1

⁢
2
⁢
π

-

k
⁢

π

n
p

+

φ
x

)

where, A kx is an amplitude of the k th first current phase, i kx , and φ x is an arbitrary phase offset, and to determine each second current phase, i jy , according to

i
jy

=

A
jy

⁢

sin
⁡

(

x
r

λ
2

⁢
2
⁢
π

-

j
⁢

π

m

Assignees

• Univ British Columbia

Inventors

• Lu Xiaodong

Classifications

• H02N15/00

  Holding or levitation devices using magnetic attraction or repulsion, not otherwise provided for (electric or magnetic devices for holding work on machine tools B23Q3/15 {; monorail vehicle propulsion or suspension B60L13/00}; sliding or levitation devices for railway systems B61B13/08; material handling devices associated with conveyors incorporating devices with electrostatic or magnetic grippers B65G47/92; separating thin or filamentary articles from piles using magnetic force B65H3/16; delivering thin or filamentary articles from magnetic holders by air blast or suction B65H29/24; bearings using magnetic or electric supporting means F16C32/04; relieving bearing loads using magnetic means F16C39/06; magnets H01F7/00; dynamo-electric clutches or brakes H02K49/00 {; electric furnaces with simultaneous levitation and heating H05B6/32}) · CPC title

• H02K41/02

  Linear motors; Sectional motors · CPC title

• H02K41/03

  Synchronous motors; Motors moving step by step; Reluctance motors (H02K41/035 takes precedence) · CPC title

• H02K41/031 Primary

  of the permanent magnet type · CPC title

• H02P8/00

  Arrangements for controlling dynamo-electric motors rotating step by step · CPC title