ISSN 1068�3712, Russian Electrical Engineering, 2010, Vol. 81, No. 10, pp. 521–523. © Allerton Press, Inc., 2010.Original Russian Text © P.V. Gulyaev, Yu.K. Shelkovnikov, A.V. Tyurikov, N.I. Osipov, 2010, published in Elektrotekhnika, 2010, No. 10, pp. 8–11.

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The development of methods and tools for high�accuracy object positioning is an important factor inthe successful development of many modern technol�ogies. The main requirement imposed on positioningdrives is increasing the accuracy of linear or angularstep movements. Step piezodrives are traditionallynoted for their top accuracy characteristics; the best ofthese drives provide a movement step on the level of 5–10 nm. Further increasing the accuracy is limited tothe presence of backlash in kinematic pairs or contactzones of pushers with a moved object. In our opinion,inertial piezodrives [1–3] possess the greatest poten�tial for increasing accuracy and are distinguished inthat their movement step is connected to the piezoele�ment deformation, the value of which may be substan�tially lower than 5–10 nm. In addition, these drives areable to work in a quasi�static mode and form singlestep movements, which facilitates the realization ofcompensation methods in increasing the accuracy[4, 5]. Another trend in the development of an inertialpiezodrive is the application of kinematic pairs, whichallows one to reduce the relation between the value ofan object’s finite movement to the value of piezoele�ment deformation used to acquire this movement.

Figures 1 and 2 present an inertial rotation�lineardrive that contains a backlash�free screw–nut pair(produced by Haydon Switch & Instruments). A car�rier plate 2 in which two piezoelectric plates 3 are can�tilever fitted in one end is joined to the screw 1 (Fig. 1)in the given pair. An inertial element 4, the weight ofwhich considerably exceeds the weight of the element 2,is mounted at the other end of the plates 3.

The drive operates as follows. The bottom of thenut is fixed on the stationary platform and the movableobject is attached to the screw 1. A dissymmetricalsaw�tooth control signal (Fig. 3) is applied to the elec�trodes of the piezoelectric plates 3. The electrodes areswitched so that, if one plate shrinks, the otherstretches. When forming a gently sloping leading edge

of the control signal, piezoelectric plates 3 bend andthe inertial element 4 slowly shifts, thus allowing thefrictional force to restrict the rotation of the screw inthe nut. While forming a sharp trailing edge, the volt�age between the coats of piezoelectric plates 3becomes zero in a short time. Due to the inertial prop�erties, the element 4 cannot arrive as quickly at the ini�tial point. As a result, piezoelectrically uncompen�sated forces of the elasticity of the deformed piezo�electric plates overcome the frictional force in thescrew–nut pair, causing the rotation and linear move�ment of the screw. This Δz movement proves to be sig�nificantly (by about two orders of magnitude) smaller

High�Accuracy Inertial Rotation�Linear Piezoelectric DriveP. V. Gulyaev, Yu. K. Shelkovnikov, A. V. Tyurikov, and N. I. Osipov

Received September 22, 2010

Abstract—The possibilities of applying backlash�free screw–nut pairs that enable one to significantly reducethe relation of the screw’s linear movement to piezoelement deformation are considered for an inertial piezo�drive. The sample of an inertial piezodrive with a kinematic screw–nut pair and the results of its experimentalstudy are described.

Keywords: piezoelement, inertial piezodrive, nanoscale movements, rotation�linear drive, backlash�freescrew–nut pair.

DOI: 10.3103/S1068371210100020

4

3

21

r

Δl

Δϕ

Fig. 1. Arrangement of the active part in inertial drive:(1) screw; (2) carrier plate; (3) piezoelectric plates;(4) inertial element.

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GULYAEV et al.

than that of the bending deformation of the piezoelec�tric plates. For the preliminary assessment of Δz andangular movement Δϕ, the following expressions canbe used:

where h is a thread pitch, Δl is the bending movementwhich overcomes gravitational center of the inertialelement during the slopping leading edge of the con�trol signal, and radius r of a circle spinned by the grav�itational center in the drive performance.

In the drive realization a screw–nut pair operatingwithout lubricating oil was used, what had significantinfluence on the drive performance. In particular, thedependence of the movement on the control signal

ΔϕΔlr

����; Δz Δϕh2π

���������≤Δlh2πr�������,= =

amplitude is nonlinear in character. Nevertheless, thepresence of dry friction enables one to achieve a quies�cent state during the formation of the gently slopingleading edge of the control signal.

The NTMDT probe microscope (Zelenograd) aswell as the PPIP�214 micromovement controller withM�214 inductive transducer were used to define thevalues of the linear movement of the screw in the pre�sented drive. In measurements using a probe micro�scope, a detecting head 1 (SMENA50 SEMI) anddrive 2 were mounted on a heavy base 3 (Fig. 4).Microscope cantilever 4 was placed above the abuttingend of the screw. Movements were registered in height�measuring mode (height signal) via semicontactivetechniques. The results are presented in Fig. 5. Mea�suring device nodes, including the screw in drive 1,were grounded in order to reduce the capacitivepickup influence. Nevertheless, the existing interfer�ence level did not permit one to conduct measure�ments of extra�small (less than 1 nm) step movements.A PPIP�214 micromovement controller was used todefine the average value of these movements and thecombined shift of the drive screw after the series ofcontrol signals was measured, after which the averagevalue of the step movement was determined. The giventechnique makes it possible to steadily register linearmovements with a step of around 0.7 nm or more. Thisvalue correlates to the relative (circular) shift in boththe screw and the nut for about 17.5 nm; it fits wellwith the minimal relative shift, which is regularlyreproduced in a kinematic pair of linear inertial piezo�drives. The drive is extremely unstable in a range ofmovement of less than 0.7 nm. However, the series ofmovement with an average step of up to 0.2 nm have

Fig. 2. Physical form of rotation�linear drive.

U

t

Fig. 3. Form of control signals.

1

4

3

2

Fig. 4. Installation diagram for movements measuring:(1) probe microscope; (2) drive; (3) platform; (4) cantilever.

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HIGH�ACCURACY INERTIAL ROTATION�LINEAR PIEZOELECTRIC DRIVE 523

been registered for certain periods of time. It seemslikely that upgrading the drive’s working stability in thismode is connected with improving the quality of theelement surfaces of the kinematic pair and refining theirrheological characteristics during manufacturing.

The studies of the drive’s other characteristicsshowed the following results. With the use of driverswith low�frequency control signals (2–3 Hz) and anoperating voltage of 350 V, the full speed of movementwill not exceed 50 μm/min. The loading capacity of

the drive’s certain realization is 120 g; it is possible toenhance the given characteristics using additionalpiezoelements. In this way, the use of kinematicscrew–nut pairs in inertial piezodrives allows one toobtain a high accuracy in step movements. The resultsare evidence that, today, this type of drive can be suc�cessfully used to position relatively light samples andtools in the nanosized dimensional range.

ACKNOWLEDGMENTS

This work was supported by the Russian Founda�tion for Basic Research, project no. 10�08�00227�a.

REFERENCES1. Bykov, V.A., Golubok, A.O., Kotov, V.V., and Sapozh�

kov, I.D., RF Patent no. 2297072, Izobret. Polezn.Modeli, 2007, no. 10.

2. Anders, M., Thaer, M., and Heiden, C., Simple Micro�postitioning Devices for STM, Surf. Sci., 1987,vol. 181, nos. 1–2, pp. 176–182.

3. Pohl, D.W., Sawtooth Nanometer Slider: A VersatileLow Voltage Piezoelectric Translation Device, Surf.Sci., 1987, vol. 181, pp. 174–175.

4. Lipanov, A.M., Gulyaev, P.V., and Shelkovnikov, E.Yu.,Precision Piezomotor for Nanodisplacements of Scan�ning Tunnel Microscope, Datchiki Sist., 2004, no. 9,pp. 30–33.

5. Afonin, S.M., The Way to Calculate the DynamicalCharacteristics of Stepper Piezomotor for Nanosizedand Microsized Displacements, Elektrichestvo, 2010,no. 4, pp. 45–51.

782

772

7621.51.00.50 t, s

z, nm

Fig. 5. Step movement curve of drive screw.