From: Peter N. <Pet...@li...> - 2009-03-25 08:59:21
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I was trying to improve odometry a bit and was reading the documentation for ODE. I was also looking around in som .cc files and found that if you omit the <mu1>***</mu1> setting in your model the friction coefficient will default to Infinity. I also found a <slip1> and <slip2> setting to tune how much a body i allowed to slip. By decreasing this value (default was 0.1) my odometry was improved. Inf friction and very little slip means that the wheel based odometry gets better. It was not perfect though and I was not able to decrease slip to much (cause then it is not possible to turn) some slip must be allowed to happen if you want to turn the wheels. Anyway thanks for your reply I will try tuning the step time too. If anyone else have any clue about the other questions, particularly the first one about the laser range, I would be happy to know. Thank You, Peter Nordin Richard Edwards wrote: > I can only answer question three. Currently if you look at the drivers > which let gazebo work as a player plugin, there is no support for > perfect odometry. Thus, you have errors that will accumulate over time, > I believe there were some mentions of tuning the update rate, etc, to > obtain a time based near perfect odometry. > > Thank You, > > Richard Edwards > > Peter Nordin wrote: > >> Hello everyone >> >> >> I recently began using gazebo, (two days ago) and I have run into some >> problems that I hope someone can help me solve. I am using the SVN head >> version of gazebo together with OGRE 1.6.1 and ODE-0.11 on a Kubuntu >> 8.04 64-bit system. >> >> >> My first question has to do with the max range setting on the sicklms200 >> laser. >> >> I want to mimic my real laser that is set to scan up to 80 meters. When >> I set the max range in my gazebo .world file the “laser beams” in gazebo >> seems to have the correct length. But when I connect gazebo to a player >> server and us a client to read the laser data, all range readings are >> divided by 10. My maximum range will be 8 meters. If I set the max value >> to 20 meters in gazebo my maximum range from player will be 2 meters. If >> I set it to 9 meters the maximum will be 0.9 meters. BUT if I set it to >> 8 meters (the default value) the range readings are not divided by 10 >> and the correct ranges are given. Why does the “range unit” change >> depending on max range setting. This does not happen on my real laser. >> >> >> Second question: >> >> In the help files at the web page it is said that the GUI can be >> deactivated if you omit the <rendering:gui> section. When I do this >> Gazebo crashes with the following message: >> >> How do I make it work? >> >> >> [server/GazeboConfig.cc:84] >> >> Gazebo Path[/usr/local/share/gazebo] >> >> [server/GazeboConfig.cc:92] >> >> Ogre Path[/usr/lib/OGRE] >> >> gazebo: OgreTextureManager.cpp:43: static Ogre::TextureManager& >> Ogre::TextureManager::getSingleton(): Assertion `ms_Singleton' failed. >> >> Aborted >> >> >> Third question: >> >> I am using a client that is following a set of lines created between >> waypoints in the world coordinate system. Once it reach the end of the >> track the order of waypoints is reversed and the robot goes back to the >> beginning and so on. I have noticed after running the simulation for a >> few minutes that the track seems to have drifted. The question is. Does >> gazebo include drift, noise, uncertainty, or slip in the odometry >> calculations? (I am using a world file based on the pioneer2dx robot >> (with the addition of one laser). The client program is only using the >> odometry for positioning in the track. >> >> >> Thank you for your help >> >> Peter >> >> >> ------------------------------------------------------------------------------ >> Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are >> powering Web 2.0 with engaging, cross-platform capabilities. Quickly and >> easily build your RIAs with Flex Builder, the Eclipse(TM)based development >> software that enables intelligent coding and step-through debugging. >> Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com >> _______________________________________________ >> Playerstage-gazebo mailing list >> Pla...@li... >> https://lists.sourceforge.net/lists/listinfo/playerstage-gazebo >> >> > > > ------------------------------------------------------------------------------ > Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are > powering Web 2.0 with engaging, cross-platform capabilities. Quickly and > easily build your RIAs with Flex Builder, the Eclipse(TM)based development > software that enables intelligent coding and step-through debugging. > Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com > _______________________________________________ > Playerstage-gazebo mailing list > Pla...@li... > https://lists.sourceforge.net/lists/listinfo/playerstage-gazebo > |