[ros-users] Navigation Stack on tight places

Gonçalo Cabrita goncabrita at gmail.com
Thu Nov 18 14:52:47 UTC 2010

Hi Steven!

"ts not a failure case but do you also see the one where it turns a little
bit away from the path then does loop around to rejoin it.?"

You we also get that a lot! The robot never sticks to the path the planner
outputs, it wonders around a lot.

We are using Roombas 560 with Eee PCs and Hokuyo lasers. We launch the
Roomba the laser and the tf broadcaster on one file and map server, amcl and
move base on another one. We have the map updaters running at 3Hz and the
path planner at 5Hz. Still sometimes the EeePC skips a loop! Furthermore, I
dunno how the Create is but our Roombas have nasty odometry! The encoders
have only 1 channel with 4 pulses per motor turn!

Anyways, I'm not familiar with the nav stack code, but I would like to help
if possible!

Gonçalo Cabrita
ISR - University of Coimbra

On Thu, Nov 18, 2010 at 2:35 PM, Steven Martin <
s34.martin at connect.qut.edu.au> wrote:

>  Yep see that one all the time. I think the implementation of DWA is
> flawed for tank steer robots.
> Its not a failure case but do you also see the one where it turns a little
> bit away from the path then does loop around to rejoin it.?
> I started implementing just pure pursuit path follower to replace DWA but
> haven't quite got it working and been too busy with other stuff. I think we
> need to implement some other local planners or just path followers.
> Also what are you using for the localization? I haven't been able to get
> AMCL to work reliably on the iCreates.
>  ------------------------------
> *From:* ros-users-bounces at code.ros.org [ros-users-bounces at code.ros.org] on
> behalf of Gonçalo Cabrita [goncabrita at gmail.com]
> *Sent:* Thursday, 18 November 2010 11:51 PM
> *To:* ros-users at code.ros.org
> *Subject:* [ros-users] Navigation Stack on tight places
>  Hi everyone!
>  We've been using the nav stack on our Roombas for quite a while now,
> mostly on the corridors of ISR without any problems.
>  However we have a small 4mx3m arena we built specifically for testing
> odor search algorithms in which we recently started to run some experiments.
> We quickly found out that the nav stack has some problems moving the robot
> around in tight places. Quite often we get the behavior that can be seen in
> the following video...
>  http://www.youtube.com/watch?v=vy9xoNvmktg
>  In the video we are running a Roomba inside our arena in Stage with
> perfect odometry. The robot stalls against a wall and stays there for
> 30mins until we stop it. On occasion the robot eventually gets out after a
> while.
>  At first I thought this could be happening because of the poor
> performance of the EeePCs the Roombas carry around or because of the
> Roomba's crappy odometry, but in Stage on a Core2Duo laptop we were able to
> see the same behavior.
>  Has anyone experienced this behavior before?
> _______________________________________________
> ros-users mailing list
> ros-users at code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ros.org/pipermail/ros-users/attachments/20101118/31909dda/attachment-0003.html>

More information about the ros-users mailing list