Nitin,

On the tutorials page <http://www.ros.org/wiki/tf/Tutorials> there are
two tutorials that are of particular interest to you:
 * "Learning about tf and time" talks about the waitForTransform method.
 * "Debugging tf problems" shows you the tf tools that will help you
debug the type of problem you are having. The output of these tools is
also very useful when asking questions on the mailinglist, as this
gives other people more insight in the state of you tf buffer.

Hope this helps!

Wim



On Tue, Jul 27, 2010 at 3:22 AM, nitinDhiman <nitinkdhiman@gmail.com> wrote:
>
> Hello everybody,
> I have boxturtle installed using debs. I am trying to interact with pioneer
> 3dx. I have following launch file
>
> <node pkg="tf" type="static_transform_publisher" name="sonar1_to_baseLink"
> args="-0.1 -0.13 -0.08 1.57 0 0  base_link  sonar1 100"/>
>
> <node pkg="p2os_driver" type="p2os" name="p2os" >
>
>
> </node>
>
> I listening to transform using code, which is similar to tutorial in tf:
>
> #include <ros/ros.h>
> #include <tf/transform_listener.h>
>
>
> int main(int argc, char ** argv)
> {
>  ros::init(argc, argv, "sonar1_tf_listener");
>
>   ros::NodeHandle node;
>
>   tf::TransformListener listener;
>   ros::Rate rate(10.0);
>   while(node.ok())
>   {
>     tf::StampedTransform transform;
>     try
>     {
>
> listener.lookupTransform("base_link","sonar1",ros::Time(0),transform);
>     } catch(tf::TransformException ex){
>       ROS_ERROR(" %s ", ex.what());
>     }
>
>     ROS_INFO(" x=%f y=%f z=%f child=%s frameId=%s ",
> transform.getOrigin().x(), transform.getOrigin().y(),
> transform.getOrigin().z(), transform.frame_id_,
> transform.child_frame_id_);//,  transform.getOrigin().yaw());
>   //  ROS_INFO(" Quaterion x=%f y=%f z=%f w=%f
> ",transform.getRotation().x() , transform.getRotation().y(),
> transform.getRotation().z(), transform.getRotation().w());
>   rate.sleep();
>   }
>
>  return 0;
> }
>
> I am getting following error which I am not able to resolve :
> nitin@tangri:/opt/ros/boxturtle/experimental/pioneer-interaction$ rosrun
> pioneer-interaction tfListenerSonar1
> [ERROR] 1280226258.499191000:  Frame id /base_link does not exist! When
> trying to transform between /sonar1 and /base_link.
>
>
> I have some previous posts about such errors but no help. Frames are
> connected correctly as odom-->base_link-->sonar1
> Thanks
> nitin
> --
> View this message in context: http://ros-users.122217.n3.nabble.com/tf-error-frame-base-link-do-not-exist-tp998832p998832.html
> Sent from the ROS-Users mailing list archive at Nabble.com.
>
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-- 
--
Wim Meeussen
Willow Garage Inc.
<http://www.willowgarage.com)