## playerstage-gazebo

 [PlayerStage-Gazebo] fiducial weirdness in gazebo From: Solly Brown - 2006-10-24 05:52:53 ```Hi all, I'm getting some odd pose readings from fiducials attached to SimpleSolids in gazebo. In particular, I've got one large box (2m x 2m x 1m) which I'm puzzled by. When the robot is standing at the corner of the box, the fiducial pose indicates the fiducial is located in the centre of the box. But when the robot stands along one of the sides of the box the fiducial pose indicates the fiducial is located right in front of the robot, on the outer face of the box (ie. not in the centre of the box). Any idea what's going on here? I thought the fiducial would just be using the c.o.m. of the object as it's location, but that appears not to be the case. Solly ```
 Re: [PlayerStage-Gazebo] fiducial weirdness in gazebo From: Solly Brown - 2006-10-24 06:31:58 ```Ah, I should spend more time reading the source code. In case anyone else comes across this in future, the answer is that the SickLMS2000 driver finds the leftmost and rightmost laser lines which hit the fiducial (in this case the entire object). It then reports the average position of these two points as the fiducial location. So, when the robot is standing next to the corner of a large box, you get scan lines hitting both sides of the object and the leftmost and rightmost fiducial points are on opposite corners of the box. Take an average and you end up with a point near the centre of the box. If the robot can only see one side of the box you get a much more sensible answer obviously. I guess the moral of the story is to actually attach little fiducial strip objects (as you would in real life) to larger objects. Cheers, Solly Solly Brown wrote: > Hi all, > > I'm getting some odd pose readings from fiducials attached to > SimpleSolids in gazebo. > > In particular, I've got one large box (2m x 2m x 1m) which I'm puzzled by. > > When the robot is standing at the corner of the box, the fiducial pose > indicates the fiducial is located in the centre of the box. > > But when the robot stands along one of the sides of the box the fiducial > pose indicates the fiducial is located right in front of the robot, on > the outer face of the box (ie. not in the centre of the box). > > Any idea what's going on here? I thought the fiducial would just be > using the c.o.m. of the object as it's location, but that appears not to > be the case. > > Solly > > ------------------------------------------------------------------------- > Using Tomcat but need to do more? Need to support web services, security? > Get stuff done quickly with pre-integrated technology to make your job easier > Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo > http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 > _______________________________________________ > Playerstage-gazebo mailing list > Playerstage-gazebo@... > https://lists.sourceforge.net/lists/listinfo/playerstage-gazebo > ```