11
the SONAR if you are operating in a noisy environment or on uneven or highly reflective floor
a heavy shag carpet, for
example. If the SONAR are too sensitive, they will “see” the carpet immediately ahead of the robot as an obstacle.
Increase the sensitivity of the SONAR by turning the gain-adjustment screw clockwise, making them more likely to see
small objects or objects at a greater distance. For instance, increase the gain if you are operating in a relatively quiet
and open environment with a smooth floor surface.
M
OTORS
,
W
HEELS
,
AND
P
OSITION
E
NCODERS
Pioneer 3 drive systems use high-speed, high-torque, reversible-DC motors, each equipped with a high-resolution
optical quadrature shaft encoder for precise position and speed sensing and advanced dead-reckoning. Motor
gearhead ratios, encoder ticks-per-revolution and tire sizes vary by robot model. However, ARCOS can correct for tire
mismatches and convert most client commands and reported server information from platform-independent distance
and heading units into platform-dependent encoder ticks, as expressed in the
DriftFactor, TicksMM
and
RevCount
FLASH parameters. Please read Chapter 6 for more details.
All Pioneer 3-DX robots come with foam-filled solid tires with knobby treads.
4
Pioneer 3-AT tires are pneumatic so that
you may configure your robot for differing terrains. In any configuration, be careful to inflate the 3-AT tires evenly and
adjust the respective
DriftFactor
,
TicksMM
and
RevCount
FLASH parameters for proper operation. We ship Pioneer
3-AT’s with the tires inflated to 23 psi each.
B
ATTERIES AND
P
OWER
Except when the DX is outfitted with the auto-recharging system (see next Chapter), Pioneer 3 robots contain up to
three, hot-swappable, seven- or nine- ampere-hour, 12 volts direct-current (VDC), sealed lead/acid batteries (total of
252 watt-hours), accessible through a hinged and latched rear door. We provide a suction cup tool to help grab and
slide each battery out of its bay. Spring contacts on the robot’s battery power board alleviate the need for manually
attaching and detaching power cables or connectors.
Balance the batteries in your robot.
Battery life, of course, depends on the configuration of accessories and motor activity. AT charge life typically ranges
from two to three hours. The DX runs continuously for six hours or more; up to four hours with onboard computer. If
you don’t use the motors, your robot’s microcontroller will run for several days on a single battery charge.
IMPORTANT:
IMPORTANT:
IMPORTANT:
IMPORTANT: Batteries have a significant impact on the balance and operation of your robot. Under most conditions, we
recommend operating with three batteries. Otherwise, a single battery should be mounted in the center, or two
batteries inserted on each side of the battery container.
Battery Indicators and Low Voltage Conditions
The User Control Panel has a bi-color LED labeled
BATTERY
that visually indicates current battery voltage. From
approximately 12.5 volts and above, the LED glows bright green. The LED turns progressively orange and then red as
the voltage drops to approximately 11.5 volts.
Aurally, the User Control Panel’s buzzer, if active (see the ARCOS
SoundTog
client command and FLASH parameter), will
sound a repetitive alarm if the battery voltage drops consistently below the FLASH
LowBattery
(11.5 VDC, by default)
level. If the battery voltage drops below the FLASH
ShutdownVolts
(11 VDC, by default) the microcontroller
automatically shuts down a client connection and notifies the computer, via the
HOST
RI
(ring indicator)
pin, to shut
down and thereby prevent data loss or systems corruption due to low batteries.
Recharging
Typical battery recharge time using the recommended accessory charger varies according to the discharge state; it is
roughly equal to three hours per volt per battery. The Power Cube accessory allows simultaneous recharge of three
swappable batteries outside the robot.
4
A ribbed-tread tire is available optionally. Contact
MobileRobots
sales for details.