Is there any topic to preview the planned path?

[sean85914]

Hello, I m using follow_joint_trajectory to control my universal robot, while I notice that after I send the trajectory goal, the robot immediately started to move. As mentioned, is there any topic to preview the planned path?

[mathias-luedtke]

As mentioned, is there any topic to preview the planned path?

There is no planning involved. The provided trajectory is executed directly by interpolating and forwarding the way-points at control rate.

[lucasw]

I see this service to to query the trajectory at a future time:

https://github.com/ros-controls/ros_controllers/blob/aa9c32b8ea8f83cb578cde82619f78e720fef89c/joint_trajectory_controller/include/joint_trajectory_controller/joint_trajectory_controller_impl.h#L657-L683

It may not be too hard to modify that to respond with a whole trajectory along a range of times instead of just a single one (like from the current time to the request time), or add a publisher in there that does that on a regular basis.