2.1 Selecting the Servomotor Capacity
2.1.2 Capacity Selection Example for a Rotary Servomotor: For Position Control
2-4
10.
Result
It has been verified that the provisionally selected Servomotor is applicable.
The torque diagram is shown below.
2.1.2
Capacity Selection Example for a Rotary Servomotor:
For Position Control
1.
Mechanical Specifications
2.
Speed Diagram
•
Verifica-
tion of
effective
torque
value:
Trms
=
=
t
1.5
(1.2
3
)
2
×
0.1 + (0.4
3
)
2
×
1.0 + (0.
3
7)
2
×
0.1
≈ 0.48
3
(N
x
m) < Rated torque...
S
ati
s
factory
TP
2
x
ta
+
TL
2
x
tc
+
Ts
2
x
td
(N
x
m)
0.1
1.5
1.0
0.1
-0.
3
7
0
0.4
3
1.2
3
Torque
Motor
S
peed
Item
Code
Value
Item
Code
Value
Load Speed
υ
L
15 m/min
Coupling Outer Diam-
eter
d
C
0.03 m
Linear Motion Section
Mass
m
80 kg
Number of Feeding
Operations
n
40 rotation/min
Ball Screw Length
B
0.8 m
Feeding Distance
0.25 m
Ball Screw Diameter
d
B
0.016 m
Feeding Time
tm
1.2 s max.
Ball Screw Lead
P
B
0.005 m
Electrical Stopping
Precision
δ
±
0.01 mm
Ball Screw Material
Density
ρ
7.87
×
10
3
kg/m
3
Friction Coefficient
μ
0.2
External Force on
Linear Motion Section
F
0 N
Mechanical Efficiency
η
0.9 (90%)
Coupling Mass
m
C
0.3 kg
υ
L
Linear motion
s
ection
S
ervomotor
Ball
s
crew
Coupling
(m/min)
tm
15
tc
ta
td
ts
t
υ
L
Motor
S
peed
Reference pul
s
e
s
Load
s
peed
Time
t
= = = 1.5 (
s
)
ta
=
tm
−
ts
−
= 1.2
−
0.1
−
= 0.1 (
s
)
tc
= 1.2
−
0.1
−
0.1
×
2 = 0.9 (
s
)
60
60
40
60
×
0.25
15
60
If ta = td and t
s
= 0.1 (
s
),
υ
L
