<s>
Amplified	B-Algorithm
piezoelectric	I-Algorithm
actuators	I-Algorithm
are	O
specific	O
actuators	B-Algorithm
using	O
piezoelectric	O
materials	O
as	O
active	O
material	O
and	O
have	O
a	O
specific	O
design	O
to	O
overcome	O
traditional	O
limitations	O
of	O
classical	O
direct	O
piezoelectric	O
actuators	B-Algorithm
,	O
the	O
limited	O
stroke	O
.	O
</s>
<s>
The	O
amplification	O
ratio	O
can	O
typically	O
reach	O
20	O
times	O
,	O
that	O
means	O
such	O
actuators	B-Algorithm
can	O
reach	O
strokes	O
of	O
1mm	O
.	O
</s>
<s>
The	O
other	O
advantage	O
is	O
that	O
this	O
kind	O
of	O
flextentional	O
actuator	B-Algorithm
is	O
very	O
reliable	O
.	O
</s>
<s>
Actuators	B-Algorithm
of	O
this	O
type	O
can	O
have	O
a	O
stroke	O
of	O
2mm	O
.	O
</s>
<s>
The	O
lever	O
arm	O
amplification	O
method	O
were	O
used	O
as	O
amplified	B-Algorithm
piezoelectric	I-Algorithm
actuator	I-Algorithm
in	O
1980s	O
as	O
a	O
piezoelectric	O
impact	O
printer	O
element	O
by	O
T.Yano	O
et	O
al	O
.	O
</s>
<s>
Piezoelectric	O
actuators	B-Algorithm
,	O
and	O
especially	O
amplified	B-Algorithm
piezoelectric	I-Algorithm
actuators	I-Algorithm
,	O
have	O
been	O
historically	O
studied	O
and	O
used	O
in	O
aerospace	O
applications	O
.	O
</s>
<s>
NASA	O
,	O
for	O
example	O
,	O
studied	O
and	O
tested	O
its	O
own	O
actuators	B-Algorithm
for	O
cryogenic	O
applications	O
.	O
</s>
<s>
The	O
space	O
industry	O
's	O
interest	O
in	O
amplified	B-Algorithm
piezoelectric	I-Algorithm
actuators	I-Algorithm
is	O
due	O
to	O
the	O
high	O
power	O
density	O
of	O
these	O
actuators	B-Algorithm
,	O
high	O
positioning	O
accuracy	O
,	O
high	O
reliability	O
,	O
and	O
low	O
power	O
losses	O
when	O
used	O
in	O
quasistatic	O
operation	O
.	O
</s>
<s>
Amplified	B-Algorithm
piezoelectric	I-Algorithm
actuators	I-Algorithm
have	O
no	O
sliding	O
parts	O
due	O
to	O
the	O
flexural	O
hinges	O
and	O
do	O
not	O
require	O
lubrication	O
.	O
</s>
<s>
Piezoelectric	O
actuators	B-Algorithm
can	O
also	O
be	O
made	O
with	O
nonmagnetic	O
materials	O
,	O
which	O
allows	O
their	O
use	O
in	O
MRI	O
machine	O
.	O
</s>
<s>
The	O
most	O
commonly	O
used	O
technology	O
is	O
the	O
amplified	B-Algorithm
piezoelectric	I-Algorithm
actuator	I-Algorithm
.	O
</s>
