Selection Example For Position Control - YASKAWA SGDH User Manual

11 Appendix

11.1.2 Selection Example for Position Control

(9) Result
The provisionally selected servomotor and SERVOPACK are confirmed to be applicable.
The torque diagram is shown below.
(N m)
Torque
11
1.73
0
-7.5
0.1
11.1.2 Selection Example for Position Control
Mechanical Specifications
Linear motion
1
Ball screw
• Load speed: V = 15 m/min
• Linear motion section mass: M = 80 kg
• Ball screw length: L
• Ball screw diameter: D
• Ball screw lead: P
• Coupling mass: M
• Coupling outer diameter: D
(1) Speed Diagram
15
Speed
(m/min)
ta
(2) Rotation Speed
• Load axis rotation speed
V
N =
P
B
• Motor shaft rotation speed with direct coupling: Gear ratio 1/R = 1/1
Therefore,
N = N
M
(3) Load Torque
9.8µ M P
T =
L
2πR η
Speed
0.1
1.0
1.5
Servomotor
Coupling
= 0.8 m
B
= 0.016 m
B
= 0.005 m
B
= 0.3 kg
C
=0 .03 m
C
Reference
V
pulse
Load
speed
c t d t s t
Time (s)
1.2
t
15
= = 3000 (min ) -1
0.005
×
R = 3000 1 = 3000 (min )
-1
9.8 × 0.2 × 80 × 0.005
B
=
2π × 1 × 0.9
• Positioning times: n = 40 times/min
• Positioning distance: = 0.25 m
• Positioning time: tm = Less than 1.2 s
• Electrical stop accuracy: δ = ± 0.01 mm
• Friction coefficient: µ = 0.2
• Mechanical efficiency: η = 0.9 (90%)
60 60
1.5 s ( )
t = ----- - = ----- - =
n 40
Where ta = td, ts = 0.1 (s)
60
ta = tm − ts − = 1.2 − 0.1 −
V
tc = 1.2 0.1 – – 0.1 × 2 = 0.9 s ( )
= 0.139 (N m)
11-4
× 0.25
60
= 0.1 (s)
15