Direct Piezoelectric Actuators Brandon Withers ECE 5320 Mechatronics Assignment #1

Outline Major Applications History of Piezoelectricity Piezomaterials Characteristics of Piezoactive Materials Piezoelectric Actuator Possibilities PI PT120-140 Piezoceramic Tubes

Reference List R. Bishop, The Mechatronics Handbook. Boca Raton, FL.:CRC Press LLC, 2002. Adaptronics Inc., (2004, Feb. 21). “Piezoelectric Actuators Tutorial” (2003) [Online]. Available: http://www.adaptronics.com/products/piezoelectric_actuators/tutorial/page_3.html PI Datasheets, (2004, Feb. 21). “PT120 – PT140 Piezoceramic Tubes” (2003) [Online]. Available: http://www.physikinstrumente.de/products/prdetail.php?sortnr=103100

To Explore Further Piezo Tutorials -- http://www.piezo.com/appdata.html -- http://www.morganelectroceramics.com/piezoguide8.html Manufacturers of Piezoelectric Actuators -- http://www.adaptronics.com -- http://www.morganelectroceramics.com -- http://www.piezo.com -- http://www.physikinstrumente.de/products/index.php Great Site With Many Links to Web Documents Dealing With Piezoelectronics -- http://citeseer.nj.nec.com/528109.html

Major Applications Fiber alignment switching, splicing and stretching modulation Micro-assembly and micro-handling systems Micro-embossing Laser cavity tuning/stabilization Beam steering/alignment Ultrasonic welding Ultrasonic cleaning

History of Piezoelectricity 1880 – Curie brothers first examined the piezoelectric effect on crystal materials which have the ability to produce electrical charges in response to externally applied forces. This is called the direct effect and is reciprocal so that the piezoelectric material also changes its dimensions under applied electrical charges. 1922 – Langevin proposed the first Actuator based on crystal materials. Late 1960s – Discovery of PZT (lead titanium-zirconate) increased the number of applications. 1988 – First market use of multilayer actuators (MLAs) derived from the high capacitor technology.

Piezomaterials Materials that exhibit a significant and useful piezoelectric effect fall into three main groups: Crystals - Natural (quartz, Rochelle salt) - Synthetic (lithium sulfate, ammonium dihydrogen phosphate) Polarized ferroelectric ceramics (main piezomaterials for engineering applications and must be artificially polarized) - Lead Zirconate Titanate (PZT) - Barium Titanate - Lead Magnesium Niobate - Modified Lead Titanate - Bismuth Titatnate Polymer fibers

Characteristics of Piezoactive Materials Piezoelectric materials are crystalline solids whose asymmetric structures create an electric dipole moment in the crystal lattice, which is sensitive to both elastic strain and applied electrical field. “Piezoelectric Actuators Tutorial”

Characteristics of Piezoactive Materials (cont.) PZT materials get their remnant polarization during a process known as the poling process. During this process the material is subjected to a high electric field at the Curie temperature and then slowly cooled with the field applied. When a stress is applied it generates an electrical field through the inverse piezoelectric effect. Since the ceramic is a dielectric medium, the electrical displacement is related to the electrical field by the following equations: S = sET + dE D = εTE + dT S = strain (m) sE = compliance of the material (m2/N) T = stress (N/m2) εT = permittivity under constant stress (F/m) E = electric field (V/m) d = piezoelectric constant (m/V or C/N) D = dielectric displacement (C/m2)

Characteristics of Piezoactive Materials (cont.) “The Mechatronics Handbook”

Piezoelectric Actuator Possibilities “The Mechatronics Handbook”

Piezoelectric Actuators Possibilities (cont.) “The Mechatronics Handbook”

PI PT120-140 Piezoceramic Tubes Application Examples Micropositioning Scanning, Microscopy (STM, AFM, etc.) Fiber Stretching / Modulation of Optical Path Length Micro Pumps / Ink-Jet Printing Micromanipulators Ultrasonic and Sonar Applications These monolithic components contract laterally (radially) and longitudinally when a voltage is applied between their inner and outer electrodes. Multi-electrode tubes are available to provide XYZ motion for use in manipulation and scanning microscopy applications “PT120 – PT140 Piezoceramic Tubes”

PI PT120-140 Piezoceramic Tubes “PT120 – PT140 Piezoceramic Tubes”

PI PT120-140 Piezoceramic Tubes Tube actuators are not designed to withstand large forces, but their high resonant frequencies make them especially suitable for dynamic operation. “PT120 – PT140 Piezoceramic Tubes”

PI PT120-140 Piezoceramic Tubes Useful Equations “PT120 – PT140 Piezoceramic Tubes”