Chris, The ability to adjust the ODE parameters for the friction coefs (esp axis specific) is not currently implemented in Gazebo world files. I was wondering how you would go about modeling an omni-wheel when this question was first proposed and I think you are onto an elegant solution.
Jordi, Nate, Where in the svn code base are the ODE parameters for wheels adjusted? Where are the XML parameters read? I am trying to give Chris an idea of where the current system would need to be patched to allow this behavior. Sawyer (Sorry I can't be of more help, I'm currently still working with the older Gazebo platform) On Monday 18 February 2008 1:57:09 pm chgans wrote: > Hi all, > > Sorry not to reply in the thread, but i've just subscribed, and so i > don't have the original email. > > I'm very interesting as well in modeling omni-directional wheel and > holonomous robot in Gazebo. > I used to work on an open source project which try to develop such a > platform[1] (as well as an ODE-based simulator). > At that time we used a "normal" wheel model, but the simple trick was to > define the ODE friction coef along the wheel axis to be very small > compared to the one along the wheel path, I'm not sure gazebo allow to > access these type of parameters from the xml file. > > I'm really new to player/stage/gazebo, I start having a look on > Saturday! Did a few build, trys (and errors), and finally get everything > running (last player/stage (pre-)release, and a fresh svn for gazebo). > Try playercam, joystick, laser, sonar, i am still exploring... and i > enjoy! Thank's to you all! > > I'm so enthusiastic, that i would like to resuscitate the WISIRC project > that i start with some of my friends in 2004, but actually what i > realized is that all we wanted to do is something like > player/stage/gazebo, but the main difference is p/s/g do it for real! :-) > Having all this framework running, will allow me to concentrate more on > HW, meca, drivers, sensors, etc of the robot (i'm actually more on HW, > low-level SW side). > For this holonomic platform we developped a specific PC104 motor control > board[2], based on 3 HCTL1100 ICs(z filter), each of these was accessed > from userspace by the "motion control" daemon, which in turn was > accessed by the path planner. The goal was to implement the same "motion > control" interface within the simulator, and we almost did, almost... > Then we decide to start working with a DSP running the motion control > algorithm (2 PIDs, one for controlling the linear position/velocity, the > second one for controlling angular position/velocity), which has > odometry directly connected (wheel encoder + laser motion sensors, such > has found in laser mouse for gamer), and then the project start slowing > down and down and ... dies. (snif! ;)) > Ah, and i didn't tell you about our plan for having DSP-based (TI C6711) > camera imagery , etc... ;) > Well, the big difference between p/s/g and wisirc, is that our goal was > to build completely from scratch (HW, Meca, SW) an 99.99% open-source > holonomic platform. As hobbyist, the fun is in the do-it-youself! (And i > don't have the money to buy all these very expensives ready-to-uses > sensors) > > I'm really happy to see all the features that p/s/g offers, very > exciting. So for now, i have to create these configuration/model files > for my bot, and start digging into the player's drivers/interfaces model. > > Have fun! > Chris. > > > [1] http://home.gna.org/wisirc/images/wizbot1-20040901/ > http://download.gna.org/wisirc/MecaWiz/wizbot-20060819/chassis_1.png > > http://download.gna.org/wisirc/MecaWiz/wizbot-20060819/new_wheel_1.png [2] > http://home.gna.org/wisirc/projects/WizHard > PS: this site is really out of date, unfortunately our newer wisirc.org > web site disapeared recently... > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Playerstage-gazebo mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/playerstage-gazebo ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Playerstage-gazebo mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/playerstage-gazebo
