20-06-2010, 05:13 PM
ultrasonic motor is a type of electric motor powered by the ultrasonic vibration of a component, the stator, placed against another component, the rotor or slider depending on the scheme of operation (rotation or linear translation) .in ultrasonic motor Dry friction is often used in contact, and the ultrasonic vibration induced in the stator is used both to impart motion to the rotor and to modulate the frictional forces present at the interface. The friction modulation allows bulk motion of the rotor and without this modulation, ultrasonic motors would fail to operate...and two different ways are generally available to control the friction along the stator-rotor contact interface, "traveling-wave vibration" and "standing-wave vibration".
see more
http://en.wikipediawiki/Ultrasonic_motor
http://noliacFiles/Billeder/Pdf/Pdf%20%20external/Piezoelectric_ultrasonic_motors.pdf
http://sea-acustica.es/Sevilla02/ult02002.pdf
http://english.peopledaily.com.cn/200112...6054.shtml
http://freepatentsonline6628045.html