“An 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
The ultrasonic motor is invented in 1980..
“Piezoelectricity is the ability of certain crystals to
generate a voltage in response to applied mechanical
stress. The word is derived from the Greek piezein, which
means to squeeze or press. The piezoelectric effect is
reversible in that piezoelectric crystals, when subjected
to an externally applied voltage, can change shape by
a small amount.”
A linear ultrasonic motor was designed using a
combination of the first longitudinal and the fourth
bending mode. The motor consisted of a straight metal
bar bonded with a piezo-ceramic element as a driving
element. The resulting displacement was amplified by
two teeth and transmitted by the frictional force
between the motor and the rail in a linear motion. The
basic design is discussed and simulations are
compared with the experimental results.
The combination of materials and simplicity of the
innovative piezoelectric motor design give:
•High power delivery (breathing mode)
•A simple friction drive Driving 1-2 micrometers at 5080kHz
•Scalable size without loss of performance
Dry friction 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 (i.e., for farther than one
vibration cycle); without this modulation, ultrasonic
motors would fail to operate.
TYPES OF USM
•Bi-directional linear standing wave USM
•Rotary Ultrasonic Motor
•Spherical ultrasonic motor
•Piezoelectric ultrasonic motors are small and light
•Because they use ultrasonic power, piezoelectric
ultrasonic motors cause no noise and little
•Due to these advantages, piezoelectric ultrasonic
motors are typically used in lens drive units of
Consequently, it is difficult to control the
ultrasonic motor while maintaining performance.
Very small, so complicated.
• This new breed of motors has many excellent
performances and features such as high torque,
low speed, simple and compact structure with
great variability in design, not interfering or being
affected by magnetic field when in operation,
power off self-brake, etc.
•Camera auto focus lenses,
•Watch motors and compact paper handling.
•Medical application within micro-surgery and sensor