Open-loop S-Curves A2
53
Detailed descriptions
The HPV 600 speed command is passed
through an internal S-curve in order to produce
the speed reference. In general, the S curve
function takes an arbitrary speed command and
generates a speed reference subject to the
conditions that the maximum accel, decel and
jerk rates not be exceeded. The speed
command is typically the target speed that the
reference is headed to.
Below shows the six parameters associated with
an S-Curve data set:
•
Accel - Maximum allowed acceleration rate
(ft/s
2
or m/s
2
)
•
Decel - Maximum allowed deceleration rate
(ft/s
2
or m/s
2
)
•
Accel Jerk In - Maximum allowed change in
acceleration towards Accel (ft/s
3
or m/s
3
)
•
Accel Jerk Out - Maximum allowed change in
acceleration from Accel (ft/s
3
or m/s
3
)
•
Decel Jerk In - Maximum allowed change in
deceleration towards Decel (ft/s
3
or m/s
3
)
•
Decel Jerk Out - Maximum allowed change in
deceleration from Decel (ft/s
3
or m/s
3
)
The S-curves are specified by four parameters:
acceleration rate (ft/s
2
or m/s
2
), deceleration
rate (ft/s
2
or m/s
2
), leveling jerk rate (ft/s
3
or
m/s
3
), and jerk rate (ft/s
3
or m/s
3
).
Since an adjustable jerk rate is helpful for
smooth landings, the jerk rates are split for ease
in elevator fine tuning. The jerk rate parameters
specifies: acceleration from the floor (ACCEL
JERK IN), jerk out of acceleration (ACCEL JERK
OUT), jerk into deceleration (DECEL JERK IN),
and the leveling into the floor (DECEL JERK
OUT).
S-Curve
There are four S-curve patterns available in the
drive and each S-curve is customized by six
parameters:
Parameters for S-curve-0 (SC0):
•
ACCEL RATE 0, DECEL RATE 0, ACCEL
JERK IN 0, ACCEL JERK OUT 0, DECEL
JERK IN 0, and DECEL JERK OUT 0
Parameters for S-curve-1 (SC1):
•
ACCEL RATE 1, DECEL RATE 1, ACCEL
JERK IN 1, ACCEL JERK OUT 1, DECEL
JERK IN 1, and DECEL JERK OUT 1
Parameters for S-curve-2 (SC2):
•
ACCEL RATE 2, DECEL RATE 2, ACCEL
JERK IN 2, ACCEL JERK OUT 2, DECEL
JERK IN 2, DECEL JERK OUT 2
Parameters for S-curve-3 (SC3):
•
ACCEL RATE 3, DECEL RATE 3, ACCEL
JERK IN 3, ACCEL JERK OUT 3, DECEL
JERK IN 3, DECEL JERK OUT 3
S-Curve Pattern Selection
The default S-curve pattern is S-curve-0 (SC0).
To make the other patterns available, the user
must assign S-CURVE SEL 0 and/or S-CURVE
SEL 1 as logic input(s). The logic input(s) can
then be used to select one of the S-curve
patterns, as follows:
Logic Inputs
Assigned
S-curves
Available
None SC0
only
SEL 0 only
SC0 or SC1
SEL 1 only
SC0 or SC2
SEL 0 & SEL 1
SC0, SC1,
SC2 or SC3
S-curve Availability
logic input
S-CURVE S-curve
SEL 1 SEL
0 selected
0 0
SCO
0 1
SC1
1 0
SC2
1 1
SC3
Selecting S-curves