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## playerstage-users

 [Playerstage-users] GetXSpeed( ) function in position2d proxy From: R C - 2007-05-30 21:07:55 ```Can someone please help me with the GetXspeed() command in the position2d proxy? In my situation the GetYspeed () always returns 0. Is it possible to get the actual X and Y velocity vectors from the GetXspeed () command. First I have made all angles for each global by using the GetYaw() command and adding that angle from the original angle. For example: double YawPosOrig[0] = {1.57}; Yawpos[0] = pp0.GetYaw() + YawPosOrig[0]; All robots angles have been globalized in the same manner. Since we are using a 2-d simulator, I would assume that traveling at a 45 degree angle that I would get a reading from both GetXSpeed()and GetYSpeed() commands. But 0 is showing up for GetYSpeed(). Will using "GetXspeed() cos Yawpos[0]" give me the X-direction velocity and "GetXspeed() sin Yawpos[0]" give me Y-direction velocity that I'm looking for?? With that same question could the GetXspeed() command be the resultant for those two vectors?? ____________________________________________________________________________________Get the Yahoo! toolbar and be alerted to new email wherever you're surfing. http://new.toolbar.yahoo.com/toolbar/features/mail/index.php ```
 Re: [Playerstage-users] GetXSpeed( ) function in position2d proxy From: Toby Collett - 2007-05-30 21:15:42 Attachments: Message as HTML ```Generally all speeds reported by robots in player are ego centric, that is their X speed is in their local coordinate system with X facing forwards. Most real robots dont have a built in concept of global position, this is provided by an external localisation sensor (such as GPS, or a map based localisation algorithm). To get global speed you would do as you suggest and perform an coordinate system tranformation from the local robot axes to the global axes using the robots heading. Keep in mind that heading estimates from odometry in the real world are quite poor compared to those in stage. Toby On 5/31/07, R C wrote: > > Can someone please help me with the GetXspeed() > command in the position2d proxy? In my situation the > GetYspeed () always returns 0. Is it possible to get > the actual X and Y velocity vectors from the GetXspeed > () command. First I have made all angles for each > global by using the GetYaw() command and adding that > angle from the original angle. For example: > > double YawPosOrig[0] = {1.57}; > Yawpos[0] = pp0.GetYaw() + YawPosOrig[0]; > > All robots angles have been globalized in the same > manner. Since we are using a 2-d simulator, I would > assume that traveling at a 45 degree angle that I > would get a reading from both GetXSpeed()and > GetYSpeed() commands. But 0 is showing up for > GetYSpeed(). Will using "GetXspeed() cos Yawpos[0]" > give me the X-direction velocity and "GetXspeed() sin > Yawpos[0]" give me Y-direction velocity that I'm > looking for?? > > With that same question could the GetXspeed() command > be the resultant for those two vectors?? > > > > ____________________________________________________________________________________Get > the Yahoo! toolbar and be alerted to new email wherever you're surfing. > http://new.toolbar.yahoo.com/toolbar/features/mail/index.php > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > Playerstage-users mailing list > Playerstage-users@... > https://lists.sourceforge.net/lists/listinfo/playerstage-users > -- This email is intended for the addressee only and may contain privileged and/or confidential information ```