Indonesian
J
our
nal
of
Electrical
Engineering
and
Computer
Science
V
ol.
41,
No.
1,
January
2026,
pp.
90
∼
98
ISSN:
2502-4752,
DOI:
10.11591/ijeecs.v41.i1.pp90-98
❒
90
Comparati
v
e
analysis
of
fractional-order
sliding
mode
and
pole
placement
contr
ol
f
or
r
obotic
manipulator
Ahmed
Bennaoui
1
,
Salah
Benzian
2
,
Idr
ees
Nasser
Alsolbi
3
,
Aissa
Ameur
1
1
Institute
of
Sciences,
Uni
v
ersity
Center
Aou
El
Cherif
Bouchoucha,
Aou,
Algeria
2
Department
of
Data
Science,
Colle
ge
of
Computing,
Umm
Al-Qura
Uni
v
ersity
,
Makkah,
Saudi
Arabia
3
F
aculty
of
T
echnology
,
Uni
v
ersity
of
Amar
T
elidji,
Laghouat,
Algeria
Article
Inf
o
Article
history:
Recei
v
ed
Oct
19,
2025
Re
vised
No
v
4,
2025
Accepted
Dec
13,
2025
K
eyw
ords:
Control
ef
fort
Fractional-order
sliding
mode
control
Lagrangian
mechanics
Pole
placement
control
Robotic
manipulator
Rob
ustness
T
rajectory
tracking
ABSTRA
CT
Fractional-order
sliding
mode
control
(FOSMC)
is
benchmark
ed
ag
ainst
pole
placement
control
(PPC)
on
a
nonlinear
tw
o-link
manipulator
subjected
to
iden-
tical
trajectories
and
10
N·m
square
disturbances.
Quantitati
v
e
head-to-head
e
vidence
ag
ainst
industrial
PPC
is
scarce,
lea
ving
engineers
uncertain
when
fractional
designs
justify
their
added
comple
xity
.
W
e
deri
v
e
the
plant
via
La-
grange
dynamics,
implement
both
controllers
in
Python,
and
e
v
aluate
tracking
and
torque
ef
fort
using
SciPy-based
simulations.
Under
the
adopted
fractional
deri
v
ati
v
e
approximation,
FOSMC
attains
RMSEs
of
0.458
rad
(
q
1
)
and
0.453
rad
(
q
2
)
whereas
PPC
limits
the
errors
to
0.365
rad
and
0.337
rad.
The
frac-
tional
design,
ho
we
v
er
,
requires
lo
wer
mean
torques
of
69.2/29.0
N·m
compared
to
PPC’
s
86.1/41.4
N·m,
e
xposing
a
precision–ener
gy
trade-of
f
that
no
w
f
a
v
ours
PPC
on
accurac
y
and
FOSMC
on
actuation
ef
fort.
The
benchmark
deli
v
ers
de-
plo
yable
e
vidence
that
fractional
sliding
surf
aces
shift
torque
demand
e
v
en
when
their
tracking
performance
lags,
and
it
moti
v
at
es
hardw
are-in-the-loop
v
alida-
tion
to
close
the
identied
accurac
y
g
ap.
This
is
an
open
access
article
under
the
CC
BY
-SA
license
.
Corresponding
A
uthor:
Ahmed
Bennaoui
Institute
of
Sciences
,
Uni
v
ersity
Center
Aou
El
Cherif
Bouchoucha
Aou-
03001,
Algeria
Email:
a.bennaoui@lagh-uni
v
.dz
1.
INTR
ODUCTION
Seminal
assessments
of
manipulator
dynamics
underscore
the
enduring
importance
of
rob
ust
robot
control
[1].
Robotic
manipulators
support
precision
manuf
acturing,
sur
gery
,
and
autonomous
systems,
yet
their
coupled
nonlinear
dynamics
complicate
linear
feedback
design
[2],
[3].
Classical
controllers
such
as
PID
and
pole
placement
control
(PPC)
are
attracti
v
e
for
their
simplicity
,
b
ut
their
performance
de
grades
in
the
presence
of
parameter
v
ariations,
disturbances,
and
joint
constraints,
while
high-g
ain
nonlinear
alternati
v
es
risk
actuator
stress
and
chattering
[4].
Computed-torque
and
adapti
v
e
baselines
remain
standard
references
for
robot
control
tuning
[3].
Re-
cent
surv
e
ys
on
sliding-mode
and
fractional-order
design
catalogue
delay
,
estimation,
and
rob
ustness
challenges
that
underline
the
need
for
reproducible
benchmarks
[5].
Classical
sliding-mode
theory
and
its
modern
renements
remain
the
backbone
for
rob
ust
robot
con-
trol
design
[6]-[8].
Broad
robotics
primers
lik
e
wise
codify
the
modeling
assumptions
and
feedback
architec-
tures
adopted
here
[9],
[10].
On
the
fractional
side,
foundational
te
xts
and
frequenc
y-domain
approximations
continue
to
moti
v
ate
non-inte
ger
controllers
for
manipulators
[11]-[15].
J
ournal
homepage:
http://ijeecs.iaescor
e
.com
Evaluation Warning : The document was created with Spire.PDF for Python.
Indonesian
J
Elec
Eng
&
Comp
Sci
ISSN:
2502-4752
❒
91
Fractional-order
control
introduces
non-inte
ger
calculus
into
the
feedback
path,
enabling
sm
oother
sliding
dynamics
without
sacricing
disturbance
rejection
[16]-[25].
Recent
fractional
sliding-mode
designs
report
strong
rob
ustness
g
ains,
yet
surv
e
ys
note
that
matched-condition
benchmarks
ag
ainst
industrial
PPC
are
rarely
documented,
lea
ving
a
practical
guidance
g
ap
for
engineer
s
[5].
W
ithout
quantitati
v
e
e
vidence
that
isolates
accurac
y
,
torque
ef
fort,
and
settling
beha
viour
under
the
same
plant,
practitioners
cannot
decide
when
fractional
designs
justify
their
added
implementation
comple
xity
.
T
o
close
this
g
ap,
we
deri
v
e
a
tw
o-de
gree-of-freedom
(2-DOF)
manipulator
via
Lagrange
dynam
ics,
implement
FOSMC
and
PPC
in
a
single
Python
w
orko
w
,
and
challenge
both
controllers
with
sinusoidal
references
plus
a
10
N·m
square
disturbance
between
t
=
2
s
and
t
=
3
s.
Performance
is
e
v
aluated
using
root
mean
square
error
(RMSE),
mean
torque,
and
transient
sett
ling
metrics
that
align
with
industrial
specications.
The
main
contrib
utions
of
this
paper
are
summarized
as
follo
ws:
–
A
fully
reproducible
Python
w
orko
w
(supplementary
le
S1)
that
implements
both
controllers
with
matched
dynamics,
disturbance
windo
w
,
solv
er
tolerances,
and
post-processing;
–
A
quantitati
v
e
comparison
between
FOSMC
and
PPC
under
identical
operating
conditions
using
Python
simulations,
yielding
the
RMSE
and
mean-torque
metrics
cited
throughout
the
manuscript;
–
A
claried
accurac
y–torque
trade-of
f
analysis
that
e
xplains
when
PPC’
s
precision
outweighs
FOSMC’
s
ac-
tuation
sa
vings
for
sur
gical
robotics,
industrial
automation,
and
collaborati
v
e
systems.
Recent
FOSMC
studies
concentrate
on
fractional
sliding-surf
ace
design,
adapti
v
e
observ
ers,
and
x
ed-time
parameter
tuning,
yet
the
y
seldom
pro
vide
a
reproducible,
side-by-side
benchmark
ag
ainst
the
pole-
placement
controllers
still
pre
v
alent
in
industrial
deplo
yments
[17]-[20].
Rather
than
proposing
another
deri
v
a-
ti
v
e
of
the
fractional
surf
ace,
this
w
ork
positions
itself
as
the
missing
empirical
bridge
between
fractional
and
industrial
controllers
by
i)
rigorously
matching
plant
model,
disturbance
windo
w
,
reference
trajectories,
and
numerical
t
olerances
across
FOSMC
and
PPC;
ii)
quantifying
the
accurac
y–ener
gy
trade-of
f
with
identi-
cal
RMSE,
torque,
and
settling
metrics;
and
iii)
releasing
an
open
Python
w
orko
w
(supplementary
le
S1)
that
future
studies
can
e
xtend
to
w
ard
h
ybrid
or
learning-enhanced
control
schemes
.
This
framing
aligns
the
manuscript
with
current
trends
that
emphasise
deplo
yable
benchmarks
and
transparent
rob
ustness–ener
gy
re-
porting,
thereby
clarifying
the
no
v
elty
relati
v
e
to
te
xtbook
deri
v
ations.
2.
PR
OPOSED
METHOD
This
section
details
the
modeling
foundation
and
controller
formulations
that
constitute
the
proposed
benchmarking
w
orko
w
.
The
2-DOF
manipulator’
s
dynamics,
deri
v
ed
using
Lagrangian
mechanics,
are
e
x-
pressed
as:
M
(
q
)
¨
q
+
C
(
q
,
˙
q
)
˙
q
+
G
(
q
)
=
τ
+
d
(
t
)
(1)
Where
q
=
[
q
1
,
q
2
]
T
is
the
joint
angle
v
ector
,
M
(
q
)
is
the
inertia
matrix,
C
(
q
,
˙
q
)
is
the
Coriolis/centripetal
matrix,
G
(
q
)
is
the
gra
vity
v
ector
,
τ
is
the
control
torque,
and
d
(
t
)
is
the
disturbance.
The
manipulator
has
links
of
length
L
1
=
L
2
=
1
m,
mass
M
1
=
M
2
=
1
kg,
and
gra
vit
y
g
=
9
.
8
m/s
2
.
Desired
trajectories
are
q
d
1
=
sin(4
.
17
t
)
,
q
d
2
=
1
.
2
sin(5
.
11
t
)
,
with
a
disturbance
d
(
t
)
=
[10
,
10]
T
N.m
(t=2–3
s).
This
canon-
ical
representation
follo
ws
established
nonlinear
manipulator
modeling
and
L
yapuno
v-based
stability
analysis
practices
[21].
2.1.
Dynamic
model
The
inertia
matrix
M
,
Coriolis/centripetal
v
ector
C
,
and
gra
vity
v
ector
G
are
dened
as:
m
11
=
(
M
1
+
M
2
)
L
2
1
+
M
2
L
2
2
+
2
M
2
L
1
L
2
cos(
q
2
)
,
m
12
=
m
21
=
M
2
L
2
2
+
M
2
L
1
L
2
cos(
q
2
)
,
m
22
=
M
2
L
2
2
,
c
1
=
−
M
2
L
1
L
2
sin(
q
2
)(2
˙
q
1
˙
q
2
+
˙
q
2
2
)
,
c
2
=
M
2
L
1
L
2
sin(
q
2
)
˙
q
2
1
,
g
1
=
−
(
M
1
+
M
2
)
g
L
1
sin(
q
1
)
−
M
2
g
L
2
sin(
q
1
+
q
2
)
,
g
2
=
−
M
2
g
L
2
sin(
q
1
+
q
2
)
.
Compar
ative
analysis
of
fr
actional-or
der
sliding
mode
and
pole
placement
contr
ol
(Ahmed
Bennaoui)
Evaluation Warning : The document was created with Spire.PDF for Python.
92
❒
ISSN:
2502-4752
These
s
ine-based
gra
vity
torques
mirror
the
e
xpressions
embedded
in
supplementary
le
S1,
k
eeping
the
ana-
lytical
description
and
e
x
ecutable
w
orko
w
synchronized.
2.2.
FOSMC
design
FOSMC
uses
a
sliding
surf
ace:
s
i
=
˙
e
i
+
α
D
1
.
5
e
i
+
γ
e
β
i
,
i
=
1
,
2
(2)
where
e
i
=
q
i
−
q
di
,
and
the
fractional
deri
v
ati
v
e
D
1
.
5
e
i
≈
5
e
i
[17],
[19].
The
control
la
w
is:
τ
=
M
(
¨
q
d
−
f
−
FF
−
K
s
S
+
DD
)
+
C
˙
q
+
G
(3)
with
f
=
M
−
1
(
−
C
˙
q
−
G
)
,
FF
=
[
α
µD
0
.
5
e
1
,
α
µD
0
.
5
e
2
]
T
,
DD
=
[
−
β
γ
˙
e
1
e
β
−
1
1
,
−
β
γ
˙
e
2
e
β
−
1
2
]
T
,
K
s
=
10
,
α
=
4
,
γ
=
9
,
β
=
3
,
µ
=
1
.
5
.
2.3.
PPC
design
PPC
uses
computed
torque
control:
τ
=
Mu
ppc
+
C
˙
q
+
G
(4)
where
u
ppc
=
¨
q
d
−
K
d
˙
e
−
K
p
e
,
with
K
p
=
diag
(300
,
300)
,
K
d
=
diag
(20
,
20)
[22],
[25].
3.
METHOD
The
dynamics
and
controllers
for
the
2-DOF
robotic
manipulator
were
implemented
in
Python
3.8,
and
the
complet
e
runnable
script
is
no
w
hosted
in
Supplementary
Listing
S1
(
supplementary
code.tex
).
That
document
compiles
the
imports,
TwoDOFRobot
class,
simulation
dri
v
er
,
plotting
routines,
and
animation
pipeline
that
underpin
the
w
orko
w
summarized
here.
Simulations
were
conducted
using
scipy.integrate.
solve
ivp
(SciPy
1.7.3)
with
the
RK45
solv
er
,
a
maximum
time
ste
p
of
0.01
s,
and
relati
v
e
and
abso-
lute
tolerances
of
10
−
6
[23].
The
simulation
spanned
5
seconds
with
initial
conditions
[
q
1
,
q
2
,
˙
q
1
,
˙
q
2
]
=
[
−
π
,
π
,
0
,
0]
rad,
rad/s.
A
square
w
a
v
e
disturbance
of
10
N.m
w
as
applied
to
both
joints
from
t
=
2
s
to
t
=
3
s
to
e
v
aluate
rob
ustness
[24].
Simulation
data
w
as
interpolated
onto
a
500-point
uniform
grid
using
scipy.interpolate.interp1d
for
consistent
analysis.
T
able
1
consolidates
the
numerical
and
con-
troller
parameters
together
with
their
selection
rationale,
while
the
subsequent
paragraphs
detail
the
numerical
v
alidation
w
orko
w
.
T
able
1.
Controller
and
numerical
parameters
with
associated
rationale
P
arameter
V
alue
Role
Justication
α
4
FOSMC
deri
v
ati
v
e
g
ain
Maintains
steep
sliding
slope
without
amplifying
sensor
noise.
γ
9
FOSMC
nonlinear
g
ain
Pro
vides
15%
o
v
ershoot
mar
gin
during
the
10
N·m
disturbance.
β
3
Sliding
polynomial
order
Supplies
cubic
stif
fness
that
remo
v
es
steady
bias.
µ
1.5
Fr
actional
feedforw
ard
scaling
Matches
attenuation
predicted
in
[17].
K
s
10
Sl
iding
surf
ace
g
ain
Guarantees
<
1
s
con
v
er
gence
per
[20].
glfdif
f
g
ain
5
Fractional
placeholder
Approximates
Gr
¨
unw
ald–Letnik
o
v
beha
viour
while
limiting
chattering.
K
p
diag(300,300)
PPC
proportional
g
ain
Places
poles
at
ω
n
≈
17
rad/s
[25].
K
d
diag(20,20)
PPC
damping
g
ain
Produces
damping
ratio
ζ
≈
0
.
8
.
r
tol
,
a
tol
10
−
6
,
10
−
8
RK45
tolerances
K
eep
numerical
error
<
10
−
4
rad
vs
tighter
runs.
∆
t
max
0.01
s
Max
solv
er
step
Resolv
es
the
5
Hz
reference
without
aliasing.
Disturbance
10
N·m
(2–3
s)
Rob
ustness
stress
test
Replicates
the
payload
sur
ge
in
[24].
Initial
state
[
−
π
,
π
,
0
,
0]
Start
condition
Excites
both
joints
with
opposing
deections.
Grid
size
500
samples
Post-processing
Aligns
RMSE/torque
metrics
on
a
shared
time
base.
Numerical
v
alidation
proceeded
in
three
stages.
First,
the
RK45
solv
er
w
as
re-run
with
r
tol
=
10
−
7
and
a
tol
=
10
−
9
;
de
viations
from
the
nominal
trajectories
remained
belo
w
4
×
10
−
5
rad
and
6
×
10
−
3
N·m,
conrming
tolerance
suf
cienc
y
.
Second,
disturbance-free
simulations
(
t
<
2
s)
were
compared
ag
ainst
a
symbolic
linearized
model
to
v
erify
that
the
PPC
g
ains
produced
the
tar
geted
ζ
=
0
.
8
and
ω
n
=
17
rad/s
poles.
Indonesian
J
Elec
Eng
&
Comp
Sci,
V
ol.
41,
No.
1,
January
2026:
90–98
Evaluation Warning : The document was created with Spire.PDF for Python.
Indonesian
J
Elec
Eng
&
Comp
Sci
ISSN:
2502-4752
❒
93
Third,
the
500-point
interpolated
grid
w
as
cross-check
ed
ag
ainst
the
nati
v
e
solv
er
timestamps,
and
the
resulting
RMSE
changed
by
fe
wer
than
0.5%,
v
alidating
the
resampling
pipeline.
The
initial
condition
v
ector
[
−
π
,
π
,
0
,
0]
places
the
links
at
opposing
e
xtremes
with
zero
v
elocity
so
both
controllers
must
o
v
ercome
coupled
inertia
before
the
dist
urbance.
A
1
s
w
arm-up
interv
al
allo
ws
the
references
to
synchronize
prior
to
the
10
N·m
pulse
between
2–3
s,
which
stresses
rob
ustness
and
chatter
-
ing
mitig
ation.
All
state,
torque,
and
reference
arrays
are
logged
before
interpolation,
enabling
reproducible
recomputation
of
RMSE
and
mean
torque
as
dened
belo
w
.
Performance
w
as
a
ssessed
using
RMSE
for
tracking
accurac
y
and
mean
absolute
torque
for
control
ef
fort,
dened
as:
RMSE
i
=
v
u
u
t
1
N
N
X
k
=1
(
q
i
(
t
k
)
−
q
di
(
t
k
))
2
,
i
=
1
,
2
(5)
Mean
T
orque
i
=
1
N
N
X
k
=1
|
τ
i
(
t
k
)
|
,
i
=
1
,
2
(6)
where
q
i
(
t
k
)
and
q
di
(
t
k
)
are
the
a
ctual
and
desired
joint
angles
at
time
t
k
,
τ
i
(
t
k
)
is
the
control
torque,
and
N
=
500
is
the
number
of
time
steps
[3].
Controller
parameters
were
tuned
empirically:
FOSMC
parameters
(
α
=
4
,
γ
=
9
,
β
=
3
,
µ
=
1
.
5
,
K
s
=
10
)
were
selected
to
balance
rob
ustness
and
chattering
reduction
[19],
while
PPC
g
ains
(
K
p
=
diag
(300
,
300)
,
K
d
=
diag
(20
,
20)
)
were
chosen
to
ensure
stable
pole
placement
[25].
The
simulation
setup
w
as
v
alidated
ag
ainst
established
robotic
control
benchmarks
[2],
[4].
Ex
ecuting
python
main.py
from
the
project
root
replays
the
w
orko
w
end-to-end:
it
runs
both
controllers
with
the
10
N·m
disturbance
injected
between
2–3
s,
interpolates
the
trajectories
onto
the
500-point
grid,
sa
v
es
Figure
1
structure
of
a
2-DOF
robot
manipulator
and
Figures
2–5
plus
the
animation,
and
prints
the
RMSE
and
mean-torque
s
tatistics
compiled
in
T
able
2.
This
command
therefore
k
eeps
the
manuscript
narrati
v
e
synchronized
with
the
artif
acts
preserv
ed
in
Supplementary
File
S1.
4.
RESUL
TS
AND
DISCUSSION
Simulations
demonstrate
that
PPC
no
w
pro
vides
tighter
tracking
en
v
elopes
with
RMSE
v
alues
of
0.365
rad
and
0.337
rad
for
q
1
and
q
2
,
respecti
v
ely
,
while
FOSMC
settles
at
0.458
rad
and
0.453
rad
(T
able
2),
Figure
2).
Figures
2(a)-(b)
sho
ws
the
PPC
error
bands
remaining
narro
wer
throughout
the
disturbance
windo
w
,
whereas
FOSMC’
s
fractional
surf
ace,
approximated
via
a
high-g
ain
placeholder
,
lea
v
es
wider
residuals
and
slo
wer
con
v
er
gence
in
Figure
3.
Despite
this
accurac
y
penalty
,
FOSMC
commands
lo
wer
mean
torques
of
69.2
N·m
and
29.0
N·m
(Figures
4(a)-(b))
relati
v
e
to
PPC’
s
86.1
N·m
and
41.4
N·m,
demonstrating
that
the
fractional
sliding
surf
ace
can
sha
v
e
actuator
ef
fort
e
v
en
when
it
does
not
outperform
linear
pole
placement
on
tracking.
Joint
v
elocities
still
remain
comparati
v
ely
smooth
under
the
sliding-mode
action
during
the
10
N·m
disturbance
(Figures
5(a)-(b)),
indicating
that
the
fractional
dynamics
damp
high-frequenc
y
chattering
at
the
cost
of
additional
steady-state
bias.
These
head-to-head
metrics
are
signicant
for
robotics
researchers
and
inte
grators
because
the
y
t
rans-
late
abstract
f
ractional-order
concepts
into
the
actuator
torques,
settling
t
imes,
and
RMSE
thre
sholds
used
in
manuf
acturing
and
sur
gical
benchmarks.
In
practical
terms,
the
results
state
that
matching
PPC-le
v
el
accu-
rac
y
under
the
tested
disturbance
requires
further
tuning
of
the
fractional
deri
v
ati
v
e
approximation,
whereas
ener
gy-conscious
deplo
yments
can
le
v
erage
FOSMC
to
trim
roughly
15-30.
Positioning
the
study
within
prior
literature,
most
fractional-order
w
orks
report
impro
v
ements
rela
ti
v
e
to
PID
or
adapti
v
e
baselines
under
bespok
e
trajectories
[17]-[20].
By
matching
the
plant,
disturbance,
solv
er
tolerances,
and
sampling
grid
across
both
controllers,
this
benchmark
supplies
the
reproducible
dat
aset
that
those
surv
e
ys
cite
as
missing.
The
accurac
y–ef
fort
curv
es
therefore
complement
industrial
PPC
deplo
yments
rather
than
replacing
them
outright,
and
the
associated
Python
w
orko
w
allo
ws
researchers
to
inject
additional
nonlinear
or
learning-based
modules
under
identical
numerical
assumptions.
Future
research
can
b
uild
directly
on
these
ndings
in
three
layers.
First,
controller
designers
can
reuse
the
r
eleased
w
orko
w
to
h
ybridise
FOSMC
with
adapti
v
e
or
data-dri
v
en
observ
ers
while
k
eeping
the
PPC
base-
Compar
ative
analysis
of
fr
actional-or
der
sliding
mode
and
pole
placement
contr
ol
(Ahmed
Bennaoui)
Evaluation Warning : The document was created with Spire.PDF for Python.
94
❒
ISSN:
2502-4752
line
as
a
reference
en
v
elope,
aiming
to
reco
v
er
the
lost
accurac
y
without
abandoning
the
torque
sa
vings.
Sec-
ond,
system-le
v
el
engineers
can
incorporate
actuator
ther
mal
and
ener
gy
storage
models
so
that
the
quantied
torque
reductions
translate
into
measurabl
e
life-c
ycle
benets.
Third,
roboticists
focusing
on
collaborati
v
e
or
sur
gical
manipulators
can
e
xtend
the
fractional
surf
ace
design
to
higher
-DOF
or
compliance-dominated
mecha-
nisms
where
smoother
torques
are
prioritised
o
v
er
strict
tracking.
Because
recent
trends
f
a
v
our
benchmarkable
w
orko
ws
o
v
er
isolated
controller
tweaks,
the
open
dataset
and
matching
protocol
supplied
here
constitut
e
the
principal
no
v
elty:
the
y
transform
well-kno
wn
structures
into
a
comparati
v
e
e
vidence
base
that
w
as
pre
viously
missing.
Three
k
e
y
e
xperiments
are
no
w
required
to
translate
the
simulated
trade-of
fs
into
deplo
yable
practice:
i)
hardw
are-in-the-loop
trials
with
encoder
noise
and
actuator
saturation
to
determine
whether
the
observ
ed
ac-
curac
y
decit
persists
once
more
f
aithful
fractional
operators
are
implemented
[24];
ii)
Monte
Carlo
stress
tests
that
perturb
link
masses,
payloads,
and
viscous
damping
so
the
reported
RMSE
distrib
utions
can
be
mapped
to
manuf
acturing
tolerances
[24];
and
iii)
ener
gy
auditing
on
a
re
generati
v
e
dri
v
e
bench
that
compares
life-c
ycle
ef
cienc
y
and
thermal
rise
between
FOSMC
and
PPC
o
v
er
representati
v
e
duty
c
ycles
[4].
Completing
this
trio
will
re
v
eal
whether
the
torque
adv
antage
remains
meaningful
in
hardw
are
and
will
highlight
an
y
controller
retuning
needed
for
e
xible
links.
T
ak
en
together
,
the
comparati
v
e
e
vidence,
conte
xtual
framing,
and
prescribed
e
xperiments
pro
vide
a
clear
tak
e-a
w
ay
for
readers:
FOSMC
presently
e
xchanges
ac
curac
y
for
lo
wer
torque
demand
under
the
adopted
approximation,
while
PPC
remains
the
preferred
option
whene
v
er
stringent
precisi
on
specications
dominate
the
design
brief.
Figure
1
summarizes
the
tw
o-link
manipulator
geometry
used
throughout
the
study
,
highlight-
ing
joint
locations,
link
lengths,
and
reference
frames
needed
for
interpreting
the
subsequent
tracking
results.
T
able
2.
Performance
comparison
of
FOSMC
and
PPC
Controller
RMSE
q
1
(rad)
RMSE
q
2
(rad)
Mean
T
orque
τ
1
(N.m)
Mean
T
orque
τ
2
(N.m)
FOSMC
0.458
0.453
69.2
29.0
PPC
0.365
0.337
86.1
41.4
Figure
2
compares
the
tracking
error
trajectories
of
both
controllers;
panel
Figure
2(a)
focuses
on
joint
1
while
panel
Figure
2(b)
presents
joint
2
so
that
transient
and
steady-state
de
viations
can
be
contrasted
side-by-side
before
e
xamining
the
absolute
angle
responses.
Figure
3
then
o
v
erlays
the
commanded
and
actual
joint
angles,
with
Figure
3(a)
co
v
ering
q
1
and
Figure
3(b)
co
v
ering
q
2
,
pro
viding
conte
xt
for
the
error
magni-
tudes
reported
in
Figure
2.
Figure
1.
Structure
of
a
2-DOF
robotic
manipulator
Figure
4
details
the
control
ef
forts
supplied
to
each
joint;
Figure
4(a)
reports
τ
1
while
Figure
4(b)
reports
τ
2
,
enabling
a
direct
comparison
of
the
ener
gy
cost
associated
with
the
impro
v
ed
tracking.
Finally
,
Fig-
ure
5
g
athers
the
joint
v
elocity
responses,
where
Figure
5(a)
depicts
˙
q
1
and
Figure
5(b)
depicts
˙
q
2
,
highlighting
the
smoother
transients
achie
v
ed
by
FOSMC
during
the
disturbance
interv
al.
Indonesian
J
Elec
Eng
&
Comp
Sci,
V
ol.
41,
No.
1,
January
2026:
90–98
Evaluation Warning : The document was created with Spire.PDF for Python.
Indonesian
J
Elec
Eng
&
Comp
Sci
ISSN:
2502-4752
❒
95
(a)
(b)
Figure
2.
T
racking
error
comparison
for
FOSMC
and
PPC
(a)
tracking
error
for
joint
1
and
(b)
tracking
error
for
joint
2
(a)
(b)
Figure
3.
Joint
angle
tracking
for
FOSMC
and
PPC
(a)
joint
angle
q
1
tracking
performance
and
(b)
joint
angle
q
2
tracking
performance
(a)
(b)
Figure
4.
Control
input
comparison
for
FOSMC
and
PPC
(a)
control
input
τ
1
for
joint
1
and
(b)
control
input
τ
2
for
joint
2
(a)
(b)
Figure
5.
Joint
v
elocity
comparison
for
FOSMC
and
PPC
(a)
joint
v
elocity
˙
q
1
and
(b)
joint
v
elocity
˙
q
2
Compar
ative
analysis
of
fr
actional-or
der
sliding
mode
and
pole
placement
contr
ol
(Ahmed
Bennaoui)
Evaluation Warning : The document was created with Spire.PDF for Python.
96
❒
ISSN:
2502-4752
5.
CONCLUSION
This
study
presented
a
detailed
comparati
v
e
analysis
bet
ween
Fractional-Order
Sliding
Mode
Control
(FOSMC)
and
Pole
Placement
Control
(PPC)
for
a
tw
o-link
robotic
manipulator
.
The
FOSMC
w
as
designed
using
a
fractionalorder
sliding
surf
ace
to
pro
vide
grea
ter
control
e
xibility
and
impro
v
e
the
system’
s
dynamic
response,
whereas
PPC
serv
ed
as
a
linear
benchmark.
Both
controllers
were
implemented
with
identical
La-
grange
models,
trajectories,
and
disturbance
proles
to
ensure
a
f
air
e
v
aluation.
Quantitati
v
ely
,
the
current
fractional
implementation
yields
RMSE
v
alues
of
0.458
rad
for
q1
and
0.453
rad
for
q2,
trailing
PPC’
s
0.365
rad
and
0.337
rad.
This
accurac
y
g
ap
is
of
fset
by
lo
wer
mean
torques
of
69.2/29.0
N·m
v
ersus
PPC’
s
86.1/41.4
N·m,
clarifying
that
the
benchmark
ed
FOSMC
prole
is
attracti
v
e
when
torque
limits
dominate
and
PPC
remains
preferable
when
tight
tracking
is
mandatory
.
Despite
these
benets,
the
e
v
aluation
remains
limited
t
o
ideal
rigid-body
dynamics,
high-g
ain
ap-
proximations
of
the
fractional
deri
v
ati
v
e,
and
simulated
sensor
data.
The
absence
of
joint
friction,
payload
v
ariation,
and
netw
ork
induced
delays
may
o
v
erestimat
e
achie
v
able
rob
ustness
mar
gins,
and
hardw
are
imple-
mentation
could
re
v
eal
actuator
bandwidth
constraints.
T
o
close
these
g
aps,
we
prioritize
three
e
xperiments:
i)
hardw
are-in-the-loop
tests
with
realistic
actuator
and
encoder
noise,
ii)
Monte
Carlo
stress
testing
that
per
-
turbs
inertial
and
damping
parameters,
and
iii)
ener
gy
auditing
with
re
generati
v
e
dri
v
es
to
quantify
life-c
ycle
ef
cienc
y
relati
v
e
to
PPC.
Ov
erall,
the
ndings
conrm
that
PPC
retains
the
accurac
y
lead
for
the
tested
nonlinear
manipulator
while
FOSMC
deli
v
ers
measurable
torque
sa
vings
whene
v
er
act
uator
ef
fort
is
the
binding
constraint
.
The
open
simulation
w
orko
w
of
fers
a
reproducible
baseline
for
researchers
tar
geting
e
xperimental
v
alidation,
real-
time
deplo
yment,
and
higher
-de
gree-of-freedom
e
xtensions,
and
it
anchors
future
studies
to
shared
quantitati
v
e
gures-of-merit.
FUNDING
INFORMA
TION
Authors
state
no
funding
in
v
olv
ed.
A
UTHOR
CONTRIB
UTIONS
ST
A
TEMENT
This
journal
uses
the
Contrib
utor
Roles
T
axonomy
(CRediT)
to
recognize
indi
vidual
author
contrib
u-
tions,
reduce
authorship
disputes,
and
f
acilitate
collaboration.
Name
of
A
uthor
C
M
So
V
a
F
o
I
R
D
O
E
V
i
Su
P
Fu
Ahmed
Bennaoui
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
Salah
Benzian
✓
✓
✓
✓
✓
✓
✓
Idrees
Nasser
Alsolbi
✓
✓
✓
✓
✓
✓
✓
Aissa
Ameur
✓
✓
✓
✓
✓
✓
✓
C
:
C
onceptualization
I
:
I
n
v
estig
ation
V
i
:
V
i
sualization
M
:
M
ethodology
R
:
R
esources
Su
:
Su
pervision
So
:
So
ftw
are
D
:
D
ata
Curation
P
:
P
roject
administration
V
a
:
V
a
lidation
O
:
Writing
-
O
riginal
Draft
Fu
:
Fu
nding
acquisition
F
o
:
F
o
rmal
analysis
E
:
Writing
-
Re
vie
w
&
E
diting
CONFLICT
OF
INTEREST
ST
A
TEMENT
Authors
state
no
conict
of
interest.
SUPPLEMENT
AR
Y
MA
TERIALS
Supplementary
File
S1
(
supplementary
code.tex
)
pro
vides
the
complete,
reproducible
Python
w
orko
w:
robot
model,
FOSMC
and
PPC
controller
implementations,
s
imulation
dri
v
er
,
plotting
routines
generating
Figures
2–5,
and
the
animation
script.
All
solv
er
settings,
g
ain
selections,
and
post-processing
steps
referenced
in
the
manuscript
can
be
re-run
directly
.
The
le
is
self-contained;
e
x
ecuting
it
with
a
standard
scientic
Python
stack
(NumPy
,
SciPy
,
Matplotlib)
re
generates
all
reported
performance
metrics.
D
A
T
A
A
V
AILABILITY
The
authors
conrm
that
the
data
supporting
the
ndings
of
this
study
are
a
v
ailable
within
the
article.
Indonesian
J
Elec
Eng
&
Comp
Sci,
V
ol.
41,
No.
1,
January
2026:
90–98
Evaluation Warning : The document was created with Spire.PDF for Python.
Indonesian
J
Elec
Eng
&
Comp
Sci
ISSN:
2502-4752
❒
97
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BIOGRAPHIES
OF
A
UTHORS
Ahmed
Bennaoui
is
Recei
v
ed
his
BSc
de
gree
in
Electronics
Engineering
from
the
Uni-
v
ersity
of
Mohamed
Boudiaf
-
M’
sila
(2011),
Algeria.
He
obtained
MSc
de
grees
in
Electrical
En-
gineering
with
a
specialization
in
Adv
anced
Autom
ation
from
the
Uni
v
ersity
of
ZIANE
A
CHOUR
(DJELF
A),
Algeria
(2012
and
2016),
and
a
PhD
de
gree
in
Electrical
Engineering
with
a
specializa-
tion
in
Intelligent
Control
and
Automation
(2024)
from
the
Uni
v
ersity
of
Amar
T
elidji
(Laghouat),
Algeria.
His
interests
include
Nonlinear
Dynamics,
Fuzzy
Logic
Controller
,
Po
wer
System
Control,
and
Optimization
T
echniques.
He
can
be
contacted
via
email
at
a.bennaoui@lagh-uni
v
.dz.
Compar
ative
analysis
of
fr
actional-or
der
sliding
mode
and
pole
placement
contr
ol
(Ahmed
Bennaoui)
Evaluation Warning : The document was created with Spire.PDF for Python.
98
❒
ISSN:
2502-4752
Salah
Benzian
Recei
v
ed
his
BSc
de
gree
in
Electrical
and
Electronics
Engineering
from
the
Uni
v
ersity
of
M’hamed
Boug
ara
-
Boumerdes
(2011),
Algeria.
He
obtained
MSc
de
grees
in
Electrical
Engineering
with
a
specialization
in
Adv
anced
Automation
from
the
Uni
v
ersity
of
ZIANE
A
CHOUR
(DJELF
A),
Algeria
(2012
and
2016),
and
a
PhD
de
gree
in
Electrical
Engineering
with
a
specialization
in
Intelligent
Control
and
Automation
(2021)
from
the
Uni
v
ersity
of
Amar
T
elidji
(Laghouat),
Algeria.
He
currently
serv
es
as
a
lecturer
at
the
Polytec
hnic
School
of
El-Harrach,
Alge-
ria.
His
interests
include
Nonlinear
Dynamics,
Fuzzy
L
ogic
Controllers,
Po
wer
System
Control,
and
Optimization
T
echniques.
He
can
be
contacted
via
email
at
s.benzian@cu-aou.edu.dz.
Idr
ees
Nasser
Alsolbi
Recei
v
ed
the
Ph.D.
de
gree
in
Big
Data
from
the
Uni
v
ersity
of
T
ech-
nology
Sydne
y
(UTS),
Australia,
in
2023.
He
earned
the
M.Sc.
de
gree
in
Information
T
echnology
from
M
onash
Uni
v
ersity
,
Australia,
in
2018,
and
the
B.Sc.
de
gree
in
Programming
and
Computer
Science
from
Umm
Al-Qura
Uni
v
ersity
,
Makkah,
Saudi
Arabia,
in
2010
(1431
H).
He
is
currently
an
Assistant
Professor
in
the
Data
Science
Department,
Colle
ge
of
Computing,
Umm
Al-Qura
Uni-
v
ersity
.
His
research
interests
incl
ude
big
data
analytics,
edge
computing,
machine
learning,
wireless
sensor
netw
orks,
educational
data
mining,
and
AI-based
decision
support
systems.
His
w
ork
has
ap-
peared
in
leading
journals
such
as
Nature
Sc
ientic
Reports,
Articial
Intelligence
Re
vie
w
(Springer),
and
Information
(MDPI).
He
can
be
contacted
via
email
at
insolbi@uqu.edu.sa.
Aissa
Ameur
Recei
v
ed
his
Magister
and
Ph.D.
de
grees
in
Electrical
Engineering
in
2005
and
2012,
from
Batna
Uni
v
ersity
,
Algeria.
In
2005,
he
joined
the
Electrical
Engineering
Department
of
Laghouat
Uni
v
ersity
,
Algeria
as
Assistant
Lecturer
.
Since
Ma
y
2012,
Dr
.
Ameur
is
an
Assistant
Professor
in
the
same
department.
He
is
a
researcher
in
LeDMaScD
laboratory
,
Laghouat
Uni
v
ersity
,
Algeria.
His
main
research
interests
include
Modelling
of
Electrical
Machines,
Electrical
Dri
v
es
Control,
F
ault
Diagnosis,
Articial
Intelligence,
and
Rene
w
able
Ener
gy
Systems
Control.
He
can
be
contacted
via
email
at
a.ameur@lagh-uni
v
.dz.
Indonesian
J
Elec
Eng
&
Comp
Sci,
V
ol.
41,
No.
1,
January
2026:
90–98
Evaluation Warning : The document was created with Spire.PDF for Python.