There was a long standing bug in the Pyrobot Simulator which allowed robots to escape from a boxed-in area (especially when dealing with robots which had evolved behavior). This was a weird bug, and I never could figure out how the little buggers could escape...until now!
The short story is that you can get updated versions of Pyro from cvs: http://pyrorobotics.org/?page=PyroDeveloperCVS The long story is an interesting mystery of the life of a bug. Here is that story briefly. The Pyrobot client robots move robots in the simulator by setting their velocities. Then 10 times a second, or so, the simulator will look to see if the robot will hit something, and if the way is clear, it moves the robot by those velocities. Now, there is a kink in this when the robot would run into something. In that case (and only in that case) the velocities are adjusted. If the robot is going to hit something, the simulator tries to slow the robot down a bit to see if it can move a little bit, if it can't move the whole amount. Also, if the robot runs into something that "gives" (a puck) then it even loses a little bit of energy/velocity, and transfers this energy to the puck. (This doesn't work with angular movement, just in the x direction to keep things simple). This generally work fine. However, every once in a while a robot inexplicable runs over an obstacle and runs amuck in the sim wild. This is impossible. Guesses? Spoiler below. It turns out that while the simulator is moving the robot, a change in velocity can come in. Now, when the robot adjusts the velocity during the robot placement, it actually is adjusting the new velocity rather than the one it started with. The first solution I tried was to put a lock/aquire/release on the velocities, but that really slowed down the user interface. The second fix which seems to work is to make a copy of the velocities when the simulator starts to move the robot, and use those during the move. Now, I don't see any more escaping robots! (Somehow I don't think this exciting mystery of the escaping robot would transfer to the big screen...) Any way, try it out. This was big problem when trying to evolve robots, and they kept getting out of their boxes. -Doug -- Douglas S. Blank Associate Professor, Bryn Mawr College http://cs.brynmawr.edu/~dblank/ Office: 610 526 601 _______________________________________________ Pyro-users mailing list Pyro-users@pyrorobotics.org http://emergent.brynmawr.edu/mailman/listinfo/pyro-users
