Re: [ompl-users] [ompl-devel] Help Please !

[Mark M. <mm...@ri...>]

Dear Sepehr Eghbali,

On Mar 7, 2011, at 8:40 AM, Sepehr Eghbali wrote:
> Hi there
> I`m a robotic master student at university of Tehran in Iran. We tend to use your library for PRM, but we have face some issues and it would be great if you could help us:
> 1. Is it possible to use a robot with joints in the "OPML app" ? ( I mean the GUI) or it is only possible to use a rigid robot in the graphical interface ? ( in all of the GUI examples we can only see a rigid robot but in a You Tube link at your website there is a real robot the do the manipulation with several revolute joints)

It is currently not possible to use articulated mechanisms in the GUI. To plan for articulated mechanisms you need to define the appropriate state space (and control space, if desired). OMPL is included with ROS. ROS includes “glue code” that maps the internal representation of the robot and the state of the environment to a space that OMPL can plan in. In future releases you can expect some simpler examples that demonstrate how you can do this yourself.

> 2. Is it also possible to use a robot with joints NOT in the OMPL GUI but with the library itself ?

Yes, the python GUI simply calls functions from the ompl and ompl_app libraries. This doesn’t immediately help with modeling a robot with joints. You may want to look at the Orocos KDL library for modeling the robot and write some additional code to interface with OMPL.

> 3. Does the library support different sampling methods like Gaussian sampling or bridge test ? Can we do it on our own ? Please tell me how we can do it and how we can visualize it.

Gaussian sampling is there: http://ompl.kavrakilab.org/classompl_1_1base_1_1ValidStateSampler.html. We haven’t added the bridge test sampler yet.

We recently added an example program that demonstrates how to use a given sampler and how to create a new one. See:
http://ompl-beta.kavrakilab.org/samplers.html
http://ompl.hg.sourceforge.net/hgweb/ompl/ompl/file/696954879eb9/demos/StateSampling.cpp
http://ompl.hg.sourceforge.net/hgweb/ompl/ompl/file/696954879eb9/demos/StateSampling.py

-- 
Mark Moll