2012-06-20 11:56:12 -0600 answered a question navfn and carrot planner? I've never seen any launch file explicitly executing those package. They are typically used as a plugin for the move_base package. Of course, you can create your own move_base that uses one of those planners. The code snippets from the wiki pages of those and the source code of move_base are helpful to understand how to use those planners. 2012-06-18 04:59:53 -0600 answered a question hector slam problem with imu The velocities in the odometry messages from hector_mapping are always zero. You can try out the angular velocity from the IMU. For the linear velocity you can differentiate the position of the odometry from hector_mapping, integrate the linear acceleration from the IMU, and combine them through averaging or filtering. My robot doesn't have an IMU, and I get the "SearchDIR angle change too large" message only when my robot is gone crazy so that the map is messed up. If you get the message often or from the beginning, I don't think augmenting your robot with an IMU will fix the issue. 2011-11-04 06:29:47 -0600 asked a question gazebo_ros_force can't find link I'm trying to model a hovercraft by applying force to a rigid body using the gazebo_ros_force plugin. I wrote the urdf file below, which has two boxes, one on top of the other. It works fine in Gazebo as long as I apply some force to the root link, base_link in this urdf file. When I attempt to apply force to the child link (test_link), I get an error message: "gazebo_ros_force plugin error: bodyName: test_link does not exist." If anyone can point out what I'm doing wrong, I would appreciate it.  Gazebo/Black 0.00001 0.00001 1000000 1.0 false 0.01 true 15.0 box_force test_link