C
ALCULATING
M
OVE
P
ROFILES
SMD34K User Manual
ADVANCED MICRO CONTROLS INC.
46
S-Curve Acceleration Equations (continued)
Trapezoidal S-Curve Acceleration
Figure R3.4 shows the speed profile of a move during its acceleration phase. The figure shows the desired
trapezoidal S-curve acceleration in red along with the equivalent constant acceleration in blue. The equivalent
constant acceleration is equal to the change in speed divided by the time it takes to achieve the change in
speed. This is the value that would have to be used if the Acceleration Jerk parameter was left at zero and
we will use this information to calculate the S-curve acceleration and the value of the Acceleration Jerk
Parameter.
Figure R3.4 Move Profile Example
In this example, the period of constant acceleration is 50% of the acceleration phase.
Speed is equal to acceleration multiplied by the time it is applied.
This is shown graphically in figure R3.5 as the area of the blue
rectangle. In order for the Trapezoidal S-curve acceleration to
reach the same speed in the same amount of time, the area of the
polygon must equal the area of the rectangle.
This means that a trapezoidal S-curve acceleration profile that is has a period of constant acceleration equal to
half of the total phase time, requires its programmed acceleration value to be 4/3 that of the constant acceler-
ation value used to achieve the same speed in the same amount of time.
Sp
e
e
d
Programmed
Speed
Starting
Speed
S = Programmed Speed – Starting Speed
s
t
t=0
Time
Constant
Acceleration
Trapezoidal S-curve
Acceleration
Acceleration =
a
=
j
=
j
=
jerk =
SMD
Acceleration
Jerk Parameter(J) =
speed
time
s
t
a
t
Ja
100
acceleration
time
100j
a
Figure R3.5 Trapezoidal Acceleration
Ac
c
e
le
ra
ti
on
t
a
c
a
s
Time
Constant
Deceleration
Trapezoidal S-Curve Deceleration
t/4
3t/4
t/2
a
s
t
2
-------
a
s
t
4
-------
a
c
t
Area of polygon = Area of rectangle
=
+
2
a
s
t
4
----------
a
s
t
4
-------
+
a
c
t
=
3
a
s
t
4
----------
a
c
t
=
a
s
4
3
---
a
c
=
Содержание SMD34K
Страница 1: ...MICRO CONTROLS INC ADVANCED U s e r M anual Manual 940 0S280 ...
Страница 6: ...TABLE OF CONTENTS SMD34K User Manual ADVANCED MICRO CONTROLS INC 6 Notes ...
Страница 50: ...CALCULATING MOVE PROFILES SMD34K User Manual ADVANCED MICRO CONTROLS INC 50 Notes ...
Страница 62: ...CONFIGURATION DATA FORMAT SMD34K User Manual ADVANCED MICRO CONTROLS INC 62 Notes ...
Страница 80: ...COMMAND DATA FORMAT SMD34K User Manual ADVANCED MICRO CONTROLS INC 80 Notes ...
Страница 100: ...LEADERS IN ADVANCED CONTROL PRODUCTS ADVANCED MICRO CONTROLS INC ...