Hi guys, that's my first post here so i hope i'm doing this right. I have a problem with Gazebo: when i initialize everything seems to work fine until i have to Respawn the robot. When i press CTRL + R (or i do it by command line) Gazebo stop publishing on the /robotname/jointstate topic for about 40 seconds, then it restarts publishing. Everything else seems to work fine, but i can't use that topic and consequentially the /tf one. I tried to unload the controller but it says i cannot do it because the controller is still running.

I'm doing a study on a lot of parameters so i have to respawn the robot every time but that seems to be a big problem for that topic and i don't know how to solve it. It would be ok for me to unload e reload every time the controller but it doesn't allow me to do it.