Really strange. Perhaps your publication didn’t get to the robot? Please check if the topic below helps:
How to publish once (only one message) into a topic and get it to work
Yes, you should not publish faster than your publisher’s queue_size can accommodate, otherwise, some messages will be dropped. You define the queue_size when you create a publisher like this:
publisher = rospy.Publisher('/cmd_vel', Twist, queue_size=5)
It’s a good idea to control your publishing rate with rate.sleep() or similar, so you don’t publish too fast.
Cheers