On Mon, Dec 27, 2010 at 10:39 AM, Jack O'Quin wrote: > On Mon, Dec 27, 2010 at 11:48 AM, Eitan Marder-Eppstein > wrote: >> On Sat, Dec 25, 2010 at 7:53 PM, wrote: >>> I have been making some experiments on ROS together with Stage, using >>> multiple mobile robots in the same environment. >>> All robots run the navigation stack. However, sometimes they collide >>> with each other. >> >> So, its true that the navigation stack doesn't do a great job of handling >> the multi-robot case, but I'd expect you to get reasonable results in Stage >> as long as the laser mounted on each robot is capable of seeing the body of >> the other robot. Have you verified that each robot in stage sees the other >> in its entirety? > > This is definitely worth checking. > > I had problems migrating simulations to recent versions of stage. > Although stage is a 2D simulation, they've added some "2.5D" features > in stage version 3. Objects now have heights, and the laser simulation > appears to send out a horizontal planar scan at the Z level of the > laser's position. A laser mounted on top of a simulated robot may "see > over the top" of another, similar robot. To echo Jack: all models in Stage (including lasers and robot bases) have heights. A sensor will only "see" other models at the same height. If you copied from standard Stage .world examples, you probably have some Pioneer-like robots with SICK-like lasers mounted on their tops in such a way that a robot's laser only sees other robots' lasers, not their bases. This is the correct result for such a robot configuration; in the real world, the laser planes don't intersect the robot bases. If you want to simulate a different (perhaps less realistic) kind of robot, you can adjust the laser heights; if you post your .world file (and also any files that are included by your .world file), we can provide some pointers on what to modify. brian.