From: Tiago V. <ts...@is...> - 2010-08-30 15:27:36
|
Hi all, I'm a new user starting to introduce myself in the world of Player and I'd like to ask to those of you who have more experience about the localization driver. When I start player, the particles of amcl are all spread on space as suppose, and I've also already increased the variance on the initial distribution. What I found strange is that once the robot starts to move the particles converge very quickly (let's say in a few seconds) and very often to a wrong position. Afterwards, even if I do some random walking, it's very difficult for the localizer to converge to the real position. I found this behavior strange, as I think particles should not converge almost immediately once I start moving. I've tried in different maps, in real and simulated robots, with different limits on the maximum and minimum number of particles, and it doesn't seem to change. Am I missing something here or may it just be the way the algorithm is? Thanks in advance. |
From: Rich M. <jp...@gm...> - 2010-08-30 15:52:33
|
AMCL has several parameters to adjust the update rate, initial guess, etc[1]. Number of samples isn't the only value that can affect the rate of convergence. For example, adding more variance to laser scans and drift to the odometry model might help slow down the convergence. I recommend that you read the description in the linked documentation if you haven't already. It does a good job describing how this AMCL implementation works. Rich [1] http://playerstage.sourceforge.net/doc/Player-svn/player/group__driver__amcl .html -----Original Message----- From: Tiago Veiga [mailto:ts...@is...] Sent: Monday, August 30, 2010 11:27 AM To: pla...@li... Subject: [Playerstage-users] amcl behavior Hi all, I'm a new user starting to introduce myself in the world of Player and I'd like to ask to those of you who have more experience about the localization driver. When I start player, the particles of amcl are all spread on space as suppose, and I've also already increased the variance on the initial distribution. What I found strange is that once the robot starts to move the particles converge very quickly (let's say in a few seconds) and very often to a wrong position. Afterwards, even if I do some random walking, it's very difficult for the localizer to converge to the real position. I found this behavior strange, as I think particles should not converge almost immediately once I start moving. I've tried in different maps, in real and simulated robots, with different limits on the maximum and minimum number of particles, and it doesn't seem to change. Am I missing something here or may it just be the way the algorithm is? Thanks in advance. ---------------------------------------------------------------------------- -- Sell apps to millions through the Intel(R) Atom(Tm) Developer Program Be part of this innovative community and reach millions of netbook users worldwide. Take advantage of special opportunities to increase revenue and speed time-to-market. Join now, and jumpstart your future. http://p.sf.net/sfu/intel-atom-d2d _______________________________________________ Playerstage-users mailing list Pla...@li... https://lists.sourceforge.net/lists/listinfo/playerstage-users |
From: Roberto G. <rg...@ro...> - 2010-08-30 17:10:42
|
Hi, I have only short experience testing amcl. What you are describing happens even in simple environments if the numbr of particles is set too low. Once the algorithm converges to a wrong estimated pose it can be hard to converge to a correct one. Unless you have a wrong setting in scale / resolution parameters of .world and .cfg files, this behaviour is normal with this algorithm. You could try: -increase number of particles: e.g. parameters pf_min_samples 10000 pf_max_samples 100000 -define (init_pose, init_pose_var) Best Regards, Robert ------------------------------------------------- Roberto Guzman Departamento de Ingenieria ------------------------------------------------- Robotnik Automation, SLL C/Berni y Catala, 53 bajo 46019 - VALENCIA - SPAIN ------------------------------------------------- Tel: +34 963383835 Fax: +34 963383580 E-mail: rg...@ro... Internet: http://www.robotnik.es ------------------------------------------------- 2010/8/30 Tiago Veiga <ts...@is...> > Hi all, > > I'm a new user starting to introduce myself in the world of Player and > I'd like to ask to those of you who have more experience about the > localization driver. > > When I start player, the particles of amcl are all spread on space as > suppose, and I've also already increased the variance on the initial > distribution. What I found strange is that once the robot starts to move > the particles converge very quickly (let's say in a few seconds) and > very often to a wrong position. Afterwards, even if I do some random > walking, it's very difficult for the localizer to converge to the real > position. > > I found this behavior strange, as I think particles should not converge > almost immediately once I start moving. I've tried in different maps, in > real and simulated robots, with different limits on the maximum and > minimum number of particles, and it doesn't seem to change. > > Am I missing something here or may it just be the way the algorithm is? > > Thanks in advance. > > > ------------------------------------------------------------------------------ > Sell apps to millions through the Intel(R) Atom(Tm) Developer Program > Be part of this innovative community and reach millions of netbook users > worldwide. Take advantage of special opportunities to increase revenue and > speed time-to-market. Join now, and jumpstart your future. > http://p.sf.net/sfu/intel-atom-d2d > _______________________________________________ > Playerstage-users mailing list > Pla...@li... > https://lists.sourceforge.net/lists/listinfo/playerstage-users > |