Calibration & Maintenance
Calibration & Maintenance
Chapter 7
Your
Team
AmigoBot is built to last a lifetime and requires little maintenance.
C
ALIBRATING
Y
OUR
R
OBOT
Your robot comes with FLASH parameters adjusted for operation on smooth, flat surfaces
with its original payload. If you operate your robot on some different surface and with
lighter or heavier loads, you probably will need to recalibrate many of its operating
parameters, such as
driftFactor
,
revCount
,
ticksMM
, and the PIDs.
The ARIA
demo
program has two modes to help you do that. In ‘
p
’osition mode,
demo
displays current heading and position. Press the ‘
r
’ key to reset these to 0 at any time.
Press the right or left arrow key to have the robot rotate 90 degrees either clockwise or
counterclockwise, respectively. The up and down arrow keys tell the robot to advance
forward or backward one meter, respectively.
ARIA
demo
’s ‘
d
’irect mode lets you change the variety of operating parameters on-the-
fly by sending the respective AmigoSH client command number and value to be used
during the current session. To replace the default values for permanent use by AmigoSH,
use AmigoSHcf.
Accordingly, to properly calibrate your robot, first use
AmigoSHcf
and record the default
values for the respective parameters, such as for
driftFactor
and
revCount
. Then
connect with the ARIA demo in position mode and move the robot. As accurately as
possible, measure its actual motion and position and use direct mode to adjust the
reported values for your robot’s current configuration and operating environment.
For example, start with
driftFactor
since its value affects both
ticksMM
and
revCount
.
Draw a line on the floor parallel to the robot’s translation travel and drive the robot
forward or back at least five meters. Adjust
driftFactor
(command #89) to minimize
the robot’s drift off that line.
Then drive the robot forward or back one or more meters and compare its actual
translation distance you accurately measure with
demo
’s AmigoSH-reported distance (x)
in millimeters. Adjust
ticksMM
(command #93) so that the numbers match.
Likewise, rotate your robot and compare your measured rotation angle to the reported
heading (
th
). Adjust
revCount
(the measure of differential encoder ticks to achieve
180-degrees rotation) accordingly (command #88).
Finally, drive the robot around and adjust its PID, velocity and acceleration values to
achieve the desired performance for the operating configuration.
When you are satisfied that the robot moves and rotates the proper distances and
headings, and drives with the proper performance, commit the new values into their
related FLASH parameters in your robot with
AmigoSHcf
and don’t forget to save a copy
in a
.rop
file for later reference.
D
RIVE
L
UBRICATION
The drive motors and gearbox are sealed and self-lubricating, so you need not fuss with
grease or oil. An occasional drop or two of oil on the axle bushings between the wheels
and the case won’t hurt.
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