<s>
Hardware-in-the-loop	B-Application
(	O
HIL	O
)	O
simulation	O
,	O
HWIL	B-Application
,	O
or	O
HITL	O
,	O
is	O
a	O
technique	O
that	O
is	O
used	O
in	O
the	O
development	O
and	O
testing	O
of	O
complex	O
real-time	O
embedded	B-Architecture
systems	I-Architecture
.	O
</s>
<s>
HIL	O
simulation	O
provides	O
an	O
effective	O
testing	O
platform	B-Device
by	O
adding	O
the	O
complexity	O
of	O
the	O
process-actuator	O
system	O
,	O
known	O
as	O
a	O
plant	O
,	O
to	O
the	O
test	O
platform	B-Device
.	O
</s>
<s>
The	O
complexity	O
of	O
the	O
plant	O
under	O
control	O
is	O
included	O
in	O
testing	O
and	O
development	O
by	O
adding	O
a	O
mathematical	B-Algorithm
representation	I-Algorithm
of	O
all	O
related	O
dynamic	O
systems	O
.	O
</s>
<s>
The	O
embedded	B-Architecture
system	I-Architecture
to	O
be	O
tested	O
interacts	O
with	O
this	O
plant	O
simulation	O
.	O
</s>
<s>
HIL	O
simulation	O
must	O
include	O
electrical	O
emulation	O
of	O
sensors	B-Application
and	O
actuators	B-Algorithm
.	O
</s>
<s>
These	O
electrical	O
emulations	O
act	O
as	O
the	O
interface	O
between	O
the	O
plant	O
simulation	O
and	O
the	O
embedded	B-Architecture
system	I-Architecture
under	O
test	O
.	O
</s>
<s>
The	O
value	O
of	O
each	O
electrically	O
emulated	O
sensor	O
is	O
controlled	O
by	O
the	O
plant	O
simulation	O
and	O
is	O
read	O
by	O
the	O
embedded	B-Architecture
system	I-Architecture
under	O
test	O
(	O
feedback	O
)	O
.	O
</s>
<s>
Likewise	O
,	O
the	O
embedded	B-Architecture
system	I-Architecture
under	O
test	O
implements	O
its	O
control	O
algorithms	O
by	O
outputting	O
actuator	B-Algorithm
control	O
signals	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
HIL	O
simulation	O
platform	B-Device
for	O
the	O
development	O
of	O
automotive	O
anti-lock	O
braking	O
systems	O
may	O
have	O
mathematical	O
representations	O
for	O
each	O
of	O
the	O
following	O
subsystems	O
in	O
the	O
plant	O
simulation	O
:	O
</s>
<s>
In	O
many	O
cases	O
,	O
the	O
most	O
effective	O
way	O
to	O
develop	O
an	O
embedded	B-Architecture
system	I-Architecture
is	O
to	O
connect	O
the	O
embedded	B-Architecture
system	I-Architecture
to	O
the	O
real	O
plant	O
.	O
</s>
<s>
Ideally	O
,	O
an	O
embedded	B-Architecture
system	I-Architecture
would	O
be	O
tested	O
against	O
the	O
real	O
plant	O
,	O
but	O
most	O
of	O
the	O
time	O
the	O
real	O
plant	O
itself	O
imposes	O
limitations	O
in	O
terms	O
of	O
the	O
scope	O
of	O
the	O
testing	O
.	O
</s>
<s>
For	O
example	O
,	O
testing	O
an	O
engine	B-Device
control	I-Device
unit	I-Device
as	O
a	O
real	O
plant	O
can	O
create	O
the	O
following	O
dangerous	O
conditions	O
for	O
the	O
test	O
engineer	O
:	O
</s>
<s>
The	O
tight	O
development	O
schedules	O
associated	O
with	O
most	O
new	O
automotive	O
,	O
aerospace	O
and	O
defense	O
programs	O
do	O
not	O
allow	O
embedded	B-Architecture
system	I-Architecture
testing	O
to	O
wait	O
for	O
a	O
prototype	O
to	O
be	O
available	O
.	O
</s>
<s>
Sensors	B-Application
communicate	O
the	O
demanded	O
flight	O
response	O
and	O
then	O
apply	O
realistic	O
force	O
feedback	O
to	O
the	O
fly-by-wire	O
controls	O
using	O
motors	O
.	O
</s>
<s>
In	O
context	O
of	O
automotive	O
applications	O
"	O
Hardware-in-the-loop	B-Application
simulation	I-Application
systems	O
provide	O
such	O
a	O
virtual	O
vehicle	O
for	O
systems	O
validation	O
and	O
verification.	O
"	O
</s>
<s>
Since	O
in-vehicle	O
driving	O
tests	O
for	O
evaluating	O
performance	O
and	O
diagnostic	O
functionalities	O
of	O
Engine	B-Device
Management	I-Device
Systems	I-Device
are	O
often	O
time-consuming	O
,	O
expensive	O
and	O
not	O
reproducible	O
,	O
HIL	O
simulators	O
allow	O
developers	O
to	O
validate	O
new	O
hardware	O
and	O
software	O
automotive	O
solutions	O
,	O
respecting	O
quality	O
requirements	O
and	O
time-to-market	O
restrictions	O
.	O
</s>
<s>
In	O
addition	O
,	O
an	O
I/O	B-General_Concept
unit	O
allows	O
the	O
connection	O
of	O
vehicle	O
sensors	B-Application
and	O
actuators	B-Algorithm
(	O
which	O
usually	O
present	O
high	O
degree	O
of	O
non-linearity	O
)	O
.	O
</s>
<s>
Finally	O
,	O
the	O
Electronic	B-Device
Control	I-Device
Unit	I-Device
(	O
ECU	O
)	O
under	O
test	O
is	O
connected	O
to	O
the	O
system	O
and	O
stimulated	O
by	O
a	O
set	O
of	O
vehicle	O
maneuvers	O
executed	O
by	O
the	O
simulator	O
.	O
</s>
<s>
Since	O
complexity	O
of	O
models	O
processing	O
is	O
dumped	O
,	O
a	O
full-size	O
HIL	O
system	O
is	O
reduced	O
into	O
a	O
portable	O
device	O
composed	O
of	O
a	O
signal	O
generator	O
,	O
an	O
I/O	B-General_Concept
board	O
,	O
and	O
a	O
console	O
containing	O
the	O
actuators	B-Algorithm
(	O
external	O
loads	O
)	O
to	O
be	O
connected	O
to	O
the	O
ECU	O
.	O
</s>
<s>
HIL	O
simulation	O
for	O
radar	B-Application
systems	I-Application
have	O
evolved	O
from	O
radar-jamming	O
.	O
</s>
<s>
Digital	O
Radio	O
Frequency	O
Memory	O
(	O
DRFM	O
)	O
systems	O
are	O
typically	O
used	O
to	O
create	O
false	O
targets	O
to	O
confuse	O
the	O
radar	B-Application
in	O
the	O
battlefield	O
,	O
but	O
these	O
same	O
systems	O
can	O
simulate	O
a	O
target	O
in	O
the	O
laboratory	O
.	O
</s>
<s>
This	O
configuration	O
allows	O
for	O
the	O
testing	O
and	O
evaluation	O
of	O
the	O
radar	B-Application
system	I-Application
,	O
reducing	O
the	O
need	O
for	O
flight	O
trials	O
(	O
for	O
airborne	O
radar	B-Application
systems	I-Application
)	O
and	O
field	O
tests	O
(	O
for	O
search	O
or	O
tracking	O
radars	B-Application
)	O
,	O
and	O
can	O
give	O
an	O
early	O
indication	O
to	O
the	O
susceptibility	O
of	O
the	O
radar	B-Application
to	O
electronic	O
warfare	O
(	O
EW	O
)	O
techniques	O
.	O
</s>
<s>
Current-generation	O
real-time	O
processing	O
platforms	B-Device
have	O
the	O
capability	O
to	O
model	O
large-scale	O
power	O
systems	O
in	O
real-time	O
.	O
</s>
<s>
These	O
types	O
of	O
simulation	O
platforms	B-Device
enable	O
the	O
evaluation	O
and	O
testing	O
of	O
large-scale	O
power	O
systems	O
in	O
a	O
realistic	O
emulated	O
environment	O
.	O
</s>
<s>
Moreover	O
,	O
HIL	O
for	O
power	O
systems	O
has	O
been	O
used	O
for	O
investigating	O
the	O
integration	O
of	O
distributed	O
resources	O
,	O
next-generation	O
SCADA	O
systems	O
and	O
power	B-Device
management	I-Device
units	I-Device
,	O
and	O
static	O
synchronous	O
compensator	O
devices	O
.	O
</s>
