Learn English – What should be used for additional information? Comma or Semi-colon

With commas instead of semicolons, it would not be clear that item 2, sensing and perception, is not a subsection of science and technology of robots or not a continuation of the motion-planning and control list. As it happens, that is not made clear with semicolons either; here is a possible interpretation of the original version:

...requiring knowledge in a number of key robotics science and technology areas, including robotics motion-planning and control; robotic sensing and perception; and robotic artificial intelligence.

By changing the order of the list you can avoid that problem:

...requiring knowledge in a number of key areas, including artificial intelligence, sensing and perception, and robot motion-planning and control.

Note, I shortened “science and technology of robot motion-planning and control” to “robot motion-planning and control”.

I would use a comma in this case.

A semicolon should only be used when the clauses you're separating can stand on their own as complete sentences. In this case, "Find out on a new episode of Off Time Radio" is a complete sentence, but "if he ever texts me back" is a dependent clause and cannot stand by itself. Thus, it would be incorrect to use a semicolon here.

It would also be incorrect to use an em dash or period for the same reason. These serve the same grammatical function as a semicolon but imply different types of relationships between the joined sentences.