<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
Hi Aswin, <br>
<br>
I'm still coming up to speed with ROS so I'm not familiar with
what's there but I did do a fair bit of research in this area (and
am reasonably familiar with the Packbot) ... here's my 2c on this
topic. <br>
<br>
Depending on how hard your "highly undulating military environment"
is, you might well have quite a challenge on your hands. Realtime,
deployable path planning through "advanced mobility" terrain
(terrain where you actually need to consider the 3D characteristics
of the terrain in detail) is still largely an open research problem,
especially with a small reconfigurable tracked vehicle such as the
Packbot. The vast majority of such autonomous systems demonstrated
in the real world "solve" the problem mostly by restricting the
robot to terrain that its intrinsic mechanical design allows it to
easily overcome, rather than via true 3D planning. <br>
<br>
Unless you plan on turning this into a full blown research project
in its own right, your best approach may be to keep to areas that
you can easily detect as drivable in your pointcloud and then do 2D
path planning over the resulting space. You won't max out the
capabilities of the Packbot (and for a basic 2D planner that isn't
able to move the flippers, a Packbot is often *less* mobile than a
similarly sized 4WD robot such as a Pioneer AT or a Volksbot RT
because the tracks can make it harder to turn and it can be more
easily high-centred) but at least you'll have something working.
Alternatively, if you can restrict your tasks to things like
detecting and climbing stairs or kerbs or other detectable,
structured objects and then 2D plan between them you might also be
able to make some progress. <br>
<br>
I'm not familiar with the modules available in ROS (that in itself
is an active research topic) but it's possible there's something
there you can start with but for a robot such as the Packbot, even
detecting what is and isn't drivable in a meaningful fashion (ie.
more than simply detecting flat ground but including steps and kerbs
that the Packbot is able to drive over) in a natural environment is
also rather non-trivial. <br>
<br>
Best of luck! :-) <br>
<br>
- Raymond<br>
<br>
On 25/02/2011 4:31 PM, Aswin Thomas wrote:
<blockquote
cite="mid:AANLkTi=2LA9sX2FemAUPJR22NwBVqqyaRzNh_9hL0CCZ@mail.gmail.com"
type="cite">
<p class="MsoNormal" style=""><span style="font-size: 11pt; color:
rgb(31, 73, 125);">Hi all,</span></p>
<p class="MsoNormal" style="">
<span style="font-size: 11pt; color: rgb(31, 73, 125);">Does
anyone know of a reliable algorithm that
can do path planning in 3D? Assuming that a 3D point cloud is
available in real
time. Are there any ROS packages are available? </span></p>
<p class="MsoNormal" style=""><span style="font-size: 11pt; color:
rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal" style=""><span style="font-size: 11pt; color:
rgb(31, 73, 125);">I have a packbot and am supposed to
navigate it autonomously in a highly undulating military
environment. I have no
idea how to go about doing it.</span></p>
<p class="MsoNormal" style=""><span style="font-size: 11pt; color:
rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal" style=""><span style="font-size: 11pt; color:
rgb(31, 73, 125);">On another note, I am a new ROS user and
have a hard time understanding the navigation tutorials. Is
there any ROS based project I can take a look? A very very
simplified one will do. Its just to help me take off since I
have a project deadline in a month.</span></p>
<p class="MsoNormal" style=""><span style="font-size: 11pt; color:
rgb(31, 73, 125);"><br>
</span></p>
<p class="MsoNormal" style=""><span style="font-size: 11pt; color:
rgb(31, 73, 125);">Thanks for your suggestions.</span></p>
<p class="MsoNormal" style="">
<span style="font-size: 11pt; color: rgb(31, 73, 125);"><br>
</span></p>
<p class="MsoNormal" style=""><span style="font-size: 11pt; color:
rgb(31, 73, 125);">Cheers</span></p>
<p class="MsoNormal" style="">
<span style="font-size: 11pt; color: rgb(31, 73, 125);">Aswin</span></p>
<pre wrap="">
<fieldset class="mimeAttachmentHeader"></fieldset>
_______________________________________________
ros-users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:ros-users@code.ros.org">ros-users@code.ros.org</a>
<a class="moz-txt-link-freetext" href="https://code.ros.org/mailman/listinfo/ros-users">https://code.ros.org/mailman/listinfo/ros-users</a>
</pre>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
/~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\
| ___ ___ | School of Computer Science |
| /__/ /__ | and Engineering, |
| / \aymond ___/heh | The University of New South Wales, |
| | UNSW SYDNEY NSW, 2052, AUSTRALIA |
| <a class="moz-txt-link-abbreviated" href="mailto:rsheh@cse.unsw.edu.au">rsheh@cse.unsw.edu.au</a> | <a class="moz-txt-link-freetext" href="http://rsheh.web.cse.unsw.edu.au">http://rsheh.web.cse.unsw.edu.au</a> |
|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
| Right now I'm having amnesia and deja vu at the same time. |
| I think I've forgotten this before. |
\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~/
</pre>
</body>
</html>