Re: [Playerstage-users] AMCL driver's abilities]

[Jared G. <jar...@dr...>]

Mark,

Here's something that might help. Look at the player manual which is on
the Playerstage CVS. It has an updated section on the "wavefront"
driver, which uses AMCL as a base driver. You can follow the
instructions in that section, which will get you started. However, in
order for these instructions to work, you will need to be working from
the CVS.



If you do not want to work from CVS, here is some code to help. We'll
use AMCL in the cave world, with the VFH driver running the robot:

1) First, start up stage: $stage simple.world

2) Start a player server with the attached config file. Make sure you
have the files cave.pnm (attached), and vfh_cave.cfg (attached) in the
directory you're calling the player server from, and that the map loads
properly when you run this: $player -p 7000 vfh_cave.cfg

3) Run the client I have attached (betternav.cpp). Its not perfect, but
is enough to get you going. You can compile it by running:
$g++ -o betternav betternav.cpp -lplayerclient
and then running:
$./betternav -g 9 9 0

There are three different coordinate frames of reference you will need
to deal with when using the wavefront path planner:   
1) The Stage frame of reference, which has its (0,0) origin at the (0,0)
pixel of the world map, or the bottom left hand corner. Your stage world
file (simple.world) will specify a robot's start position in these
coordinates.  
2) The localize frame of reference, which has (0,0) at the center of
your world map. If you are giving the robot a guess as to where the
robot s starting position is, you will use this frame of reference. The
wavefront planner and the amcl driver use this coordinate system.  (i.e.
when you specify robot pose in the betternav.cpp file, or in the
vfh_cave.cfg file)
3) The robot's frame of reference, or the frame of reference for a
position driver, which will have its origin (0,0) at the point where the
robot starts. This means that an interface such as VFH receives goal
commands with reference to that point (i.e. when you call $./betternav
-g 9 9 0)



Jared Giesbrecht
Defence Scientist
Autonomous Land Systems
Defence R&D Canada Suffield
Phone: 403-544-4709
Email: Jar...@dr...