[ros-users] using navigation to move a robot

[Ben Reiter]

Dear Ros-User-Group,

My name is Ben Reiter, I'm a student a WashU in Saint Louis. I'm trying to
get our robot to move using the navigation stack, but I'm having some
issues. I'll try to explain exactly what I'm doing, and what is going wrong.
At the moment, the robot fails to move at all. In rviz, I can see that the
transforms all are working, that it can definitely see the laser, and is
starting to build a map.

I run:

Roscore
Hokuyo_node
rflex b21 (the interaction with our robot which sets up tf, b21/cmd_vel, and
a host of other nodes)
gmapping slam_mapping
move_base move_base (which starts move_base_node)
simple_navigation_goals (from this tutorial:
http://www.ros.org/wiki/navigation/Tutorials/SendingSimpleGoals)

I'm currently having 2 issues, they might or might not be related.

First, when I run move_base I try to remap its output 'cmd_vel' to
'b21/cmd_vel' by writing "rosrun move_base move_base cmd_vel:=b21/cmd_vel"
However, this seems to have no effect because move_base still creates a
cmd_vel topic that doesn't communicate with the b21/cmd_vel.

Second, and I think more importantly, when I run simple_navigation_goals,
the output is as follows:

Waiting for the move_base action server to come up
Sending goal
The base failed to move forward 1 meter for some reason

And then it exits.

Just after "sending Goal" in simple_navigation_goals, when looking at the
output of move_base, I get this error:

[ERROR] 1269463020.665478000: Aborting because a valid plan could not be
found. Even after executing all recovery behaviors

I'm not really sure how to fix this, Any help would be appreciated.

Thanks,

Ben Reiter
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