Curtis 1268 Manual,
Rev. D
41
7
Response to Full Throttle Release (Compression Braking)
The way the vehicle responds when the throttle is completely released can be
modified using the
DECEL
,
REGEN C/L
, brake mapping, and negative field mapping
parameters. Braking parameters should be set for M1 and M2 forward speeds
and for reverse speed.
When the throttle is released, the
DECEL
rate acts to drive the armature
PWM down to zero, but the
BRAKE MAP
will ensure that the braking (regen)
current is limited to the value for the present vehicle speed. This allows a profile
to be specified that allows high initial braking torque, softening to a milder
torque as the vehicle slows down. Alternatively, you can set up a profile with
strong braking down to zero speed. A lower
DECEL
value will also provide a more
immediate strong braking feel.
step
1. Set the brake mapping parameters to the default values shown
in Example A on the next page.
Note: With the default settings, maximum braking torque
is specified at top speed, tailing off to a much milder torque at
low speeds.
step
2. Drive the vehicle at full speed on flat ground and release the
throttle, paying attention to the feel of vehicle braking. If the
initial braking is too sudden, increase the
DECEL
value. If the
initial braking is too strong, lower the
BRAKE MAX
or increase the
BRAKE MAP END
.
When setting a very mild compression braking feel, beware
of setting the
BRAKE MAX
and
REGEN C/L
to values that will inhibit
the controller’s ability to maintain top speed braking—in both
throttle applied and throttle released conditions—on a downhill
grade.
If the braking torque remains too strong after the vehicle
has been brought to a slower speed, reduce the
BRAKE MAP
and
BRAKE MIN
parameters, and increase the
BRAKE MAP START
. These
adjustments will act to limit the braking torque at the lower
speeds.
If, on the other hand, you want to
increase
braking torque
at lower speeds, increase the
BRAKE MAP
or
BRAKE MIN
parameters,
or reduce the
BRAKE MAP START
.
Note: The setting of the brake mapping and
DECEL
parameters will also affect the
feel of the vehicle deceleration during partial throttle releases. After completing
procedure
7
for full throttle release, make sure the deceleration during partial
throttle release is acceptable.
5 — TUNING GUIDE