WAM Arm – User’s Manual
www.barrett.com
© 2008 Barrett Technology®, Inc.
Document: D1001, Version: AH.00
53 of 80
Problem:
During operation, you hear a “popping” sound accompanied by a distinct nasty
smell.
Reason(s):
1.
An electrical component burned up.
Solution(s):
a)
Carefully record all events leading up to the failure. Contact Barrett for repair.
Problem:
The WAM returns to home position before starting a new trajectory.
Reason(s):
1.
The first point in the trajectory is the home position.
Solution(s):
a)
Inspect the trajectory file with a text editor to determine if this is the case. Every
trajectory file is just a comma-delimited file with time (in seconds) in the left column
and (depending on the mode) the joint positions or the Cartesian positions in the
remaining columns.
Problem:
A slight knocking can be heard when moving a particular cable circuit of the
WAM (it may also be felt if backdriving the WAM by hand). As the knock occurs,
a slight backlash may be felt.
Reason(s):
1.
Debris in a joint bearing.
Solution(s):
a)
Apply several drops of oil (3-in-1, or WD-40 in liquid form or another light viscosity
mineral oil should work). The debris has about a 50% chance of working itself out
eventually.
2.
Loose ball-bearing retainer
Solution(s):
a)
Eliminated in newer designs, usually does not interfere with operation except for
clicking noise.
3.
Insufficient motor shaft axial preload/shimming – the rotor/shaft should not be able to
move axially inside the motor.
Solution(s):
a)
Return to Barrett for repair.
Problem:
The robot fails to follow scaled trajectories.
Reason(s):
1.
The WAM does not have the latest OS/firmware/software.
Solution(s):
a)
Follow the directions on wiki.barrett.com to update your firmware/software.
Problem:
Gravity Compensation does not operate correctly.
Reason(s):
1.
The wam.conf file links to the incorrect configuration file based on the present WAM setup
Solution(s):
a)
Change the link in wam.conf to the correct configuration file: WAM4 (4-DOF),
WAM7 (4DOF with Wrist), or WAMG (4DOF with gimbals)
2.
The parameters in the configuration file do not match your system’s actual configuration.
Solution(s):
a)
Check the linked configuration file for the following:
•
Correct the tool center point (DH parameters d, a, alpha). These are offsets from
the final link’s frame.
•
Correct the tool Center-Of-Mass (COM), relative to the tool center point
•
Correct the tool mass
•
In pre-2007 WAMs, Motor 4 (M4) was located over M3. After 2007, M4 was
reversed and located over M2. The transformation matrices need to match your
