This paper presents a novel magnetically levitated (maglev) stage developed to meet the ever-increasing precise positioning requirements in nanotechnology. This magnetic levitator has 6 independent linear actuators necessary and sufficient to generate all 6-degree-of-freedom (6-DOF) motions. This minimum-actuator design concept led to a compact, 200 g lightweight moving part and the power consumption less than of a Watt, thereby reducing the thermal-expansion error drastically. The analysis and sizing of the magnetic linear actuators and the working principle of the maglev stage are presented. We designed and implemented stabilizing controllers for 6-DOF motion control with the dynamic model based on the actuator analysis. Test results showed nanoscale step responses in all six axes with 2nmrms horizontal position noise. A noise propagation model and analysis identified the capacitance sensor noise and the floor vibration as the dominant noise sources in the vertical and horizontal dynamics, respectively. A comparison of noise performances with controllers closed at 25, 65, and 90 Hz crossover frequencies illustrated how the selection of the control bandwidth should be made for nanopositioning. Experimental results including a 250μm step response, sinusoidal and square-wave trajectories, and spherical motion generation demonstrated the three-dimensional (3D) nanoscale motion-control capability of this minimum-actuator magnetic levitator. Potential applications of this maglev stage include manufacture of nanoscale structures, atomic-level manipulation, assembly and packaging of microparts, vibration isolation for delicate instruments, and seismic motion detection.

1.
Sitti
,
M.
, 2001, “
Survey of Nanomanipulation Systems
,”
Proc. IEEE-NANO 2001
, pp.
75
80
.
2.
Sitti
,
M.
, and
Hashimoto
,
H.
, 2000, “
Controlled Pushing of Nanoparticles: Modeling and Experiments
,”
IEEE/ASME Trans. Mechatron.
1083-4435,
5
(
2
), pp.
199
211
.
3.
Bauer
,
C.
,
Bugacov
,
A.
,
Koel
,
B. E.
,
Madhukar
,
A.
,
Montoya
,
N.
,
Ramachandran
,
T. R.
,
Requicha
,
A. A. G.
,
Resch
,
R.
, and
Will
,
P.
, 1998, “
Nanoparticle Manipulation by Mechanical Pushing: Underlying Phenomena and Real-Time Monitoring
,”
Nanotechnology
0957-4484,
9
(
4
), pp.
360
364
.
4.
Taylor
,
R. M.
, 1994, “
The Nanomanipulator: A Virtual-Reality Interface to a Scanning Tunneling Microscope
,” Ph.D. Dissertation, University of North Carolina at Chapel Hill, Chapel Hill, NC.
5.
Yu
,
M. F.
,
Dyer
,
M. J.
,
Rohrs
,
H. W.
,
Lu
,
X. K.
,
Ausman
,
K. D.
,
Her
,
J. V.
, and
Ruoff
,
R. S.
, 1999, “
Three-Dimensional Manipulation of Carbon Nanotubes under a Scanning Electron Microscope
,”
Nanotechnology
0957-4484,
10
(
3
), pp.
244
252
.
6.
Requicha
,
A. A. G.
,
Meltzer
,
S.
,
Terán
,
A. F. P.
,
Makaliwe
,
J. H.
,
Sikén
,
H.
,
Hsieh
,
S.
,
Lewis
,
D.
,
Koel
,
B. E.
, and
Thompson
,
M. E.
, 2001, “
Manipulation of Nanoscale Components with the AFM: Principles and Applications
,”
Proc. IEEE-NANO 2001
, pp.
81
86
.
7.
Egshira
,
Y.
,
Kosaka
,
K.
,
Takada
,
S.
,
Iwabuchi
,
T.
,
Baba
,
T.
,
Moriyama
,
S.
,
Harada
,
T.
,
Nagamoto
,
K.
,
Nakada
,
A.
,
Kubota
,
H.
, and
Ohmi
,
T.
, 2001, “
0.69nm Resolution Ultrasonic Motor for Large Stroke Precision Stage
,”
Proc. IEEE-NANO 2001
, pp.
397
402
.
8.
Jayawant
,
B. V.
, 1981,
Electromagnetic Levitation and Suspension Techniques
,
Edward Arnold Ltd.
, London.
9.
Hajjaji
,
A. E.
, and
Ouladsine
,
M.
, 2001, “
Modeling and Nonlinear Control of Magnetic Levitation Systems
,”
IEEE Trans. Ind. Electron.
0278-0046,
48
(
4
), pp.
831
838
.
10.
Takahara
,
K.
, 1988, “
Development of a Magnetically Suspended, Tetrahedron-Shaped Antenna Pointing System
,”
Proc. NASA CP-2056, 22nd Aerospace Mechanisms Symp.
, pp.
133
147
.
11.
Gupta
,
A. A.
,
Germann
,
L. M.
, and
Medbery
,
J. D.
, 1991, “
Six Degree-of-Freedom Magnetically-Suspended Fast Steering Mirror (MSFSM) Tracks Atmospheric Turbulence While Providing Focusing and Collimation Travel
,”
Proc. 14th Annual AAS Guidance and Control Conference
, AAS
91
039
.
12.
Hollis
,
R. L.
, and
Salcudean
,
S. E.
, 1993, “
Lorentz Levitation Technology: a New Approach to Fine Motion Robotics, Teleoperation, Haptic Interface, and Vibration Isolation
,”
Proc. 5th International Symposium on Robotics Research
, pp.
1
18
.
13.
Salcudean
,
S. E.
,
Davis
,
H.
,
Chen
,
C. T.
,
Goertz
,
D. E.
, and
Tryggvason
,
B. V.
, 1992, “
Coarse-Fine Residual Gravity Cancellation System with Magnetic Levitation
,”
IEEE International Conference on Robotics and Automation
, pp.
1641
1647
.
14.
Shan
,
X.
,
Kuo
,
S.-K.
,
Zhang
,
J.
, and
Menq
,
C.-H.
, 2002, “
Ultra Precision Motion Control of a Multiple Degrees of Freedom Magnetic Suspension Stage
,”
IEEE/ASME Trans. Mechatron.
1083-4435,
7
(
1
), pp.
67
78
.
15.
Jung
,
K. S.
, and
Baek
,
Y. S.
, 2002, “
Study on a Novel Contact-Free Planar System Using Direct Drive DC Coils and Permanent Magnets
,”
IEEE/ASME Trans. Mechatron.
1083-4435,
2
(
1
), pp.
35
43
.
16.
Chen
,
S. S.
,
Busch-Vishniac
,
I. J.
, 1995, “
A Magnetically Levitated, Automated, Contact Analytical Probe Tool
,”
IEEE Trans. Semicond. Manuf.
0894-6507,
8
(
1
), pp.
72
78
.
17.
Kim
,
W.-J.
, and
Trumper
,
D. L.
, 1998, “
High-Precision Magnetic Levitation Stage for Photolithography
,”
Precis. Eng.
0141-6359,
22
(
2
), pp.
66
77
.
18.
Holmes
,
M. L.
, 1994, “
Analysis and Design of a Magnetically Suspended Precision Motion Control Stage
,” M.S. Thesis, University of North Carolina at Charlotte, Charlotte, NC.
19.
Holmes
,
M. L.
,
Hocken
,
R.
, and
Trumper
,
D.
, 2000, “
The Long Range Scanning Stage: a Novel Platform for Scanned Probe Microscopy
,”
Precis. Eng.
0141-6359,
24
(
3
), pp.
191
209
.
20.
Kim
,
W.-J.
, and
Maheshwari
,
H.
, 2002, “
High-Precision Control of a Maglev Linear Actuator with Nanopositioning Capability
,”
Proc. of 2002 American Control Conference
, pp.
4279
4284
.
21.
Kim
,
W.-J.
,
Gu
,
J.
, and
Maheshwari
,
H.
, 2002, “
Six-DOF Mechatronic Nanopositioning Device
,”
Proc. 2nd IFAC Conference on Mechatronics Systems
, pp.
909
914
.
22.
Slocum
,
A. H.
, 1992,
Precision Machine Design
,
Prentice-Hall, Inc.
, Englewood Cliffs, NJ, Chap. 2.
23.
Gu
,
J.
, 2003, “
Development of a 6-Degree-of-Freedom Magnetically Levitated Instrument with Nanometer Precision
,” M.S. Thesis, Texas A&M University, College Station, TX.
24.
Haus
,
H. A.
, and
Melcher
,
J. R.
, 1989,
Electromagnetic Fields and Energy
,
Prentice-Hall, Inc.
, Englewood Cliffs, NJ.
25.
Earnshaw
,
S.
, 1842, “
On the Nature of the Molecular Forces which Regulate the Constitution of the Luminiferous Ether
,”
Trans. Cambridge Philos. Soc.
0371-5779,
7
, pp.
97
112
.
26.
Maybeck
,
P. S.
, 1979,
Stochastic Models, Estimation, and Control
,
Academic Press
, NY.
27.
Papoulis
,
A.
, 1991,
Probability, Random Variables and Stochastic Processes
,
2nd ed.
,
McGraw-Hill Higher Education
, NY.
You do not currently have access to this content.