In unit 5 section 5.3 there were such a node tag in the launch file that weren’t commented after that at all:
<!-- start fake calibration -->
<node pkg="rostopic" type="rostopic" name="fake_joint_calibration"
args="pub /calibrated std_msgs/Bool true" />
I just would like to know what is it’s function, or what would happen without it ?
This is true Noor.
That node, the only thing it does is to publish a True in the topic /calibrated. We need to have that topic for compatibility with the real robot. The real robot (which you can practice with here) requires to have the real joints calibrated. That is a process that is done on startup of the robot. Until the calibration process is not finished, the topic /calibrated doesn’t say True. This topic is used by other programs to wait until True and then continue.
That is why, in order to not interrupt those programs we are publishing the fake calibration, saying to those programs that the calibration was done properly (it required no calibration because it is a simulation)