piezoelectric properties inchworm linear motor

1. • Piezoelectric properties
• Inchworm Linear motor

9. The inchworm motor is a device that uses piezoelectric actuators to move a shaft
with nanometer precision.
In its simplest form, the inchworm motor uses three piezo-actuators mounted inside a tube
and electrified in sequence to grip a shaft, moved in a linear direction.
Motion of the shaft is due to the extension of the lateral piezo pushing on two clutching
piezos; the actuation process of the inchworm motor is a six step cyclical process after the
initial relaxation and initialization phase.
All three piezos are relaxed and unextended. To initialize the inchworm
Inchworm Liner motor
The inchworm motor can be used in the patch clamping of biological cells. This technique is most
performed with an optical microscope and micromanipulator holding a glass pipette; the inchworm
motor is ideal in patch clamping because it provides the operator with an instantaneous, precise and
predictable motion without drift. Unimorph Bimorph Miniature Piezo SteppingMotor Principle.

10. Step 1. Extension of the lateral
piezo.
Step 2. Extension of the aft clutch
piezo.
Step 3. Relaxation of the forward
clutch piezo.
Step 4. Relaxation of the lateral
piezo.
Step 5. Extension of the forward
clutch piezo.
Step 6. Relaxation of the aft clutch
piezo.

11. To move long distances the sequence of six steps is repeated manytimes in rapid
succession.
Once the motor has moved sufficiently close to the desired final position, the
motor may be switched to an optional fine positioning mode.
In this mode, the clutches receive constantvoltage, the lateral piezo voltage is
adjusted to an intermediate value, under continuous feedback control, to obtain
the desired final position; the inchworm motor is used in scanning tunneling
microscopes.
An STM requires nanometer scale control of its scanning tip near the material;
this control can be accomplished by connecting the scanning tip to the shaft of
the inchworm motor.
The inchworm motor, in turn, allows control in a direction normal to the plane of
the observed material's surface.
Movement across the surface is referred to as movement in the x-y plane,
whereas movement normal to the surface is referred to as movementin the z-
direction.
Movement of the scanning tip by the inchworm motor is either manually
controlled or automatically controlled by connecting the motor to a feedback
system

12. END