Did you check if the clocks of the robot computer and your laptop are synchronized? Wim On Wed, Dec 1, 2010 at 5:11 PM, devpriya wrote: > > Hi Guys, > > The setup is like this, I have a MobileRobots PeopleBot. I wrote a > playerstage wrapper for ROS so that ROS running on my laptop can communicate > with the player server on the robot. The connection is through a wired > ethernet. > > I am seeing a strange case of tf failure here. The transform from base_link > to base_laser fails unless I subtract 1.75 seconds from the timestamp of > laser transforms! > > I can see that the messages from odometery and laser scan are coming at > almost the same rate. Even the timestamps are almost identical and I am > timestamping these messages on the laptop. > > The workaround of subtracting 1.75 seconds from the laser timestamp fixes > the base_link to base_laser transform but now when I try to run the > 2dnavigation stack, the transform from map to base_laser won't happen > because the messages are too old. Even increasing the tolerance to something > like 2 seconds doesn't help as the buffer gets filled with old messages! > > I guess my hack of subtracting 1.75 seconds at the first place was a wrong > move and I want to know if anybody had faced any such problem and if yes > then how did you debug it? > > I have tried all the debugging techniques mentioned in the tf tutotrial on > ROS's website. Everything looks fine in view_frames or roswtf. > > One more piece of information which might be helpful is that I am running > Ubuntu on VmWare on MacBook Pro. I don't know if virtual machine has > something to do in this, may be timing issue! > > If you need any more info to help me out, please let me know and I will > furnish the same. > -- > View this message in context: http://ros-users.122217.n3.nabble.com/Tf-failure-while-working-with-a-Pioneer-P3DX-tp2003281p2003281.html > Sent from the ROS-Users mailing list archive at Nabble.com. > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users > -- -- Wim Meeussen Willow Garage Inc.