Sevcon Dragon8 - Driveability Profiles

Doc. # 177/52705
Rev. 1.0
64
In torque mode, both inner and outer wheel maximum speeds are scaled according the outer wheel map.
The outer wheel target torque comes from the throttle. The inner wheel target torque is scaled to the
outer wheel actual torque according the inner wheel map.
In object 2913
h
, 0 to 1 is represented by values in the range 0 to 32767. The inner wheel is scaled
according to the outer wheel. Where a demand (pu) of -1 is shown at 90º for the inner wheel, this means
the inner wheel demand will be equal and opposite to the outer wheel.
The calculated steering angle can be read at 2623
h
. An angle value of -32767 indicates full steering to
the left, +32767 full steering to the right and 0 is straight ahead.
If steering switches are used instead of a steering potentiometer, only part of the steering map is used as
shown in Table 22.
Value
Description
2913
h
,9
Outer wheel speed during inner wheel cutback
2913
h
,11
Outer wheel speed during inner wheel reversal
2913
h
,17
Inner wheel cutback speed
2913
h
,19
Inner wheel reverse speed
Table 22 Objects to set when using steering switches
NOTE: During a turn the inner wheel speed is slowed by power reduction instead of braking to prevent
the outer wheel motor working against the inner wheel motor.
Driveability profiles
WARNING: Ensure driveability profiles are disabled when not required. Activation of a
driveability profile can cause driving parameters to change.
Driveability profiles allow you to set maximum values for speed, torque, acceleration and deceleration
for use in a range of operational situations. In addition, in torque mode, there are ramp rates for speed
limits as well. Torque mode acceleration/decelerationFigure 27 and Figure 28 show the change in speed
and torque target under various driving conditions over a period of time.