Re: [Playerstage-users] Questions. Sorry if they are bad questions.

[Jordi <mu...@gm...>]

Have you tried your program on gazebo?


=46riday 31 March 2006 16:36=E3=80=81Tim Reynolds =E3=81=95=E3=82=93=E3=81=
=AF=E6=9B=B8=E3=81=8D=E3=81=BE=E3=81=97=E3=81=9F:
> Hello
>
> A fellow student and I are doing research into various AI techniques for
> controlling robots and are using Player/Stage.
>
> First, Player/Stage is amazing software, and you guys have done a wonderf=
ul
> job.
>
> Part of this while project is that we are developing a framework / API for
> easily writing bot AI and controlling the timing of actions.
> We are testing a few AI techniques with this: Standard state machine, swa=
rm
> bots and genetic algorithms.
>
> We have run into a few problems and were wondering if we could get any
> insight.
>
> 1) Grippers
> When we use grippers to grab another bot, a few different things can
> happen, none of which are what we expected.
> a - If the bot that is grabbed is not active, it loses all devices attach=
ed
> to it. (This is of course using Stage). A bot is able to connect to it
> later, but when it tries to read from the sensors the whole simulation
> crashes.
> b - If the bot that is grabbed is active, once it is grabbed the simulati=
on
> crashes upon calling read() in Player.
>
> We are not sure if we are doing something wrong here. Is this just a 'not
> possible' thing at this point?
> One area we were looking to use this in is part of our simulation, which =
is
> a game of Jail Break. We have 'guard' and 'prisoner' bots. The game is for
> the prisoners to get the correct keys to open doors and get to the 'goal'
> area. Keys are just objects, doors are actually bots using color blob
> finders and omni-directional movement.
>
> The two ways it was going to be used was for the 'guard' bots to grab the
> 'prisoner' bots, and the other was just a novel game type we wanted to try
> where we have both the swarm bots and the state machine bots in the same
> area. The 'key' for the swarm bots is a normal key, whereas the key for t=
he
> state machine bot is one of the swarm bots. The bot would have to catch o=
ne
> to get out. Childish, but fun.
>
> 2) Pan-Tilt-Zoom
> I have not personally worked on this yet, but my friend tells me that when
> he tries to adjust the PTZ for, say, the blob finder, it causes the FOV to
> go to zero, or what appears to be zero. Was wondering if there were known
> issues with that or a particular way for doing that.
>
> 3) Disconnects and the Player client crashing.
> When I close Stage, all connected player clients crash with a socket read
> error [Success] ( A broken pipe error). This is a problem. The destructors
> aren't getting called. I tried using a try / catch block to see if there
> was an exception I could catch, but there doesn't seem to be one. This is=
 a
> bit of a problem. However, I am assuming I am just missing something here.
> I THINK the player client is crashing on the read() command, so is there
> something I can check, variable or method, before calling read to ensure
> that the socket is still open? Does Stage send out any kind of message
> before it closes that would indicate to the bot that it needs to close as
> well?
>
> Thank you very much.
>
> After I finish up the API, I would love to send it to you guys, see what
> you think. /shrug.
>
> Tim Reynolds
> ra...@gm...