Application of piezomaterials in ultrasonic motors and

nanopositioning Valentinas Snitka

Research Center for Microsystems&NanotechnologyKaunas University of Technology,

LITHUANIA

http://www.microsys.ktu.lt

1st International Workshop on Smart Materials and Structures, Kiel, 2004

OUTLINE• Introduction• Travelling wave motors• Standing wave ultrasonic motors• Nanopositioning with SWUM• SAW ultrasonic motors• Ultrasonic levitation, ultrasonic bearings• Flexure nanopositioning• Multilayer piezoactuators• Future applications

Many different actuator technologies are used for linear motion

• Piezoactuators – decades from infancy to industry• Advantages:

smaller componenthigher resolutionhigh acting force

Problems: control, feedback

Obstacle for implementation: price/pcs, mass production, low voltage piezoceramic

Inchworm motors

Inchworm motor schematic. 1,2,3 – piezoceramic elements.1- clamping, 2 – extraction, 3 – clamping, 2- retraction

Principle of work : stepping motion based on piezoactuatorsextraction- retraction. Resolution – subnanometer, vacuum compatible Disadvantage –slow

Travelling wave motorsInvented before 1980 at “Vibrotechnika”Kaunas University, Lithuaniaand in Japan 1982

a)

b)

Elliptical motion generated at the rotor surface and teeth tips of travelling wave.a - schematic, b - design.

How does it work?

Travelling wave motors

Principle of cylindrical mode motor:4 segments of piezoceramics exiting with phase shift

Transportable object: slider, microparticles

Surface Acoustic Wave MotorsInvented in “Vibrotechnika” Kaunas University, Lithuania,Snitka (SU patent 1985)Tomikawa, Japan, 1991

SAW amplitude-10 nm

Surface Acoustic Wave Motors

Nanometers resolution, 0.6 m/s speed

Piezoelectric filmon substrate

Near Field Acoustic Levitation

Driving force – throughsqueezed gas film

Schematic

Configuration set-up

Configuration of transportation system

Standing wave ultrasonic motors

Bimodal vibration plate

Micro-push motors with rectangular plate

Micro-push motor with annular plate

Invented in Vibrotechnika Institute, KTU, Lithuania0 1973

1-Input driving pulse, Nano-steps displacement2-Output micro-step response Resolution - 10 nm

Linear nanopositioning

Start-stop reversible motion

Vmax = 90 mm/sec during 0.7 sec

Flexure X-Y nanopositioning stages

Ferroelectrics multi-layer stack

- Subnanometer resolution- Nanometer ‘accuracy

X-Y stage for Bio-AFM

Near Field Scanning Optical Microscope

Ultrasonic and piezomotor are the next generation motors especially in small size applications

Main advantages:

- high torque-weight ratio- silent operation- direct drive- self-breaking- low-inertia- maximum efficiency at high torque- negligible magnetic field

Future applications:

- automobile industry- robotics- microelectronics- MEMS technology- space missions- magnetic resonance imaging- nanopositioning- consumer goods.

Externalelectrodes

Internalelectrodes

Piezoceramic

Co-fired multilayer technology

Multilayer-based components enable a wide range of shapes to be produced

Provide the flexibility needed to design high-precision components

Low control voltage

Conclusions

Mass-production, simple and flexible manufacturing of new generation ferroelectrics film is a key for many Micro-Nano technology and products developments

THANK YOU !