[ros-users] robot_pose_ekf

[Jan Elseberg]

Hi everyone,

I am attempting to use robot_pose_ekf to combine the measurements from 
my IMU with the odometry of the robot. For this purpose I have 
configured robot_pose_ekf to not use visual_odometry input. Running the 
launch file, every topic is correctly connected. However, the ekf filter 
repeatedly prints:

   Odom sensor activated
   odom sensor not active any more

and I get this debug message:

   [DEBUG] 1275662646.245471000: Could not transform imu message from 
/xsens to base_footprint. Imu will not be activated yet.

As my tf-tree is set up according to the navigation-stack tutorial my 
robots coordinate frame is called "base_link", instead of 
"base_footprint". In order to set up a connection to my robots frame, I 
have added this static transform:

   <node pkg="tf" type="static_transform_publisher" name="baselink" 
args="0 0 0 0 0 0 /base_link /base_footprint 20" machine="mach"/>

With this the robot_pose_ekf now publishes fused pose estimates. Now 
this warning pops up from time to time:

    [ WARN] 1275665674.294791000: Robot pose ekf diagnostics discovered 
a potential problem.

I have also noticed two additional frame_ids that are not connected to 
the rest of the tf-tree, namely "odom_combined" and "odomwheel". From 
this I gather that what I have done is not the proper way to solve the 
problem. But what is the proper way to solve it? Is there a way to remap 
frame_ids similar to remapping topics? Or is this not the cause of my 
problem at all?


  Regards,
     Jan Elseberg