SECTION 3 - CHASSIS & TURNTABLE
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3-5
3.6
DRIVE/STEERING SPEED CONTROL
The Drive/Steering Speed Control system uses the steering
sensors from the steering control system (see Section 3.5,
Steering Control System) to increase operator control and
comfort by reducing the effect of turning the chassis and the
resulting lateral platform speed. The system proportionally
varies the drive speed based on the predicted turning radius
of the chassis for both coordinated and conventional two
wheel steer modes. The tighter the turn the slower the allow-
able drive speed. As crab steer does not steer on a radius, full
drive speed is maintained regardless of steer angle.
NOTE:
For more detailed information concerning system adjust-
ment and operation, refer to Section 6 - JLG Control Sys-
tem.
3.7
TRACTION CONTROL SYSTEM
The Traction Control System uses the steering sensors from
the steering control system (see Section 3.5, Steering Control
System) to optimize the performance of the drive system. This
is especially important due to the disparity of wheel speeds
generated between the inside and outside wheels of the
extended axle chassis with large steering angle capability.
The steering sensors are used to predict the rolling path and
therefore the required wheel speed of each wheel as the steer-
ing angles change and steering modes change. The control
system can then command the ideal flow from each of the two
drive pumps, one for the right side of the machine and one for
he left side. Two flow dividers, one for the right side front to
back and one for the left side front to back absorb the varia-
tion in wheel speed front to back.
NOTE:
For more detailed information concerning system adjust-
ment and operation, refer to Section 6 - JLG Control Sys-
tem.
3.8
DRIVE ORIENTATION SYSTEM
The Drive Orientation System (DOS) is intended to indicate to
the operator conditions that could make the direction of
movement of the chassis different than the direction of move-
ment of the drive/steer control handle. The system indicates to
the operator the need to match the black and white direc-
tional arrows on the platform control panel to the arrows on
the chassis. The system uses a proximity switch mounted on
the hydraulic swivel, an indicator light, and a spring return
override switch on the platform display panel. The proximity
switch trips when the turntable is swung ± 45 degrees off cen-
ter of the normal driving position. This occurs roughly when
the main boom is swung past a rear tire. When the turntable is
in the normal drive position with the boom between the rear
tires, no indications or interlocks are made. When the machine
is actively driving when the turntable is swung past the switch
point, the system is ignored until drive/steer is released. When
drive is initiated with the boom swung past the switch point,
the DOS indicator will flash and the drive/steer functions will
be disabled. The operator must engage the DOS override
switch to enable Drive/steer (high drive will remain disabled).
When the DOS is enabled, the DOS indicator will be illumi-
nated continuously and a 3-second enable timer will be
started and will continue for 3 seconds after the end the last
drive/steer command. If the timer expires, the DOS override
switch must be re-engaged to enable drive/steer.
NOTE:
For more detailed information concerning system adjust-
ment and operation, refer to Section 6 - JLG Control Sys-
tem.
3.9
GROUND CONTROL ENABLE SYSTEM
The ground controls include the use of a function enable sys-
tem for the operation of directional functions from the ground
control panel. To operate any directional function, the func-
tion enable switch must be held in combination with the
directional function switch. This switch doubles as the auxil-
iary power switch. When the engine is not running, activating
this switch will operate auxiliary power. When the engine in
running, activating this switch will enable directional func-
tions. Releasing this switch during function commands will
stop the function movement. Unlike the platform enable, no
timer or sequence logic is imposed on the use of the function
enable.
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