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4 PARAMETERS FOR POSITIONING CONTROL
(5) Speed change (fixed time method)
Operation in which a speed change during deceleration is executed is shown
below.
Fixed position stop acceleration
/deceleration time
(Indirect setting device)
0
Command speed V
2
(After speed change)
V1
Speed
Time
Command speed V
0
(Before speed change)
Before speed change
Before speed
change
Time
t1
OFF
ON
ab
0
Servo program start
V
0 a
(V2 - V1) b
Speed change V2 (Deceleration)
Acceleration
Deceleration from
speed V
1 to V2
Deceleration from
speed V
1 to V2
Same slope as
acceleration decrease
1)
Speed change command Speed difference
Acceleration/
deceleration time
Maximum
acceleration
Operation
1) Deceleration from speed
V
0 to 0
(V
2 - V1) b (V2 - V1) b
(a) The acceleration is decreased until the
acceleration becomes from acceleration
to"0" at speed change. This inclination of
acceleration section 2 (acceleration
decrease section) is calculated based on
the acceleration/deceleration time before
speed change.
(b) Deceleration processing is executed.
(Note): The acceleration time "t1" is
lengthened than "b
(100.0 + D1R +
D2R)
100.0", because the
acceleration continues until the
acceleration reaches zero after a
speed change.
POINTS
When a speed change is executed during decreasing acceleration of advanced
S-curve acceleration/deceleration, in order to maintain smoothness of acceleration,
the speed will continue to increase until acceleration reaches zero. Therefore, the
time for speed change is lengthened.
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