The most common and most likely answer to this crossword clue is the 11 letter word CYBERNETICS
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More clues leading to the result CYBERNETICS
Buddy explains!

The straight part
We know that "Study of control systems" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case study of control systems = cybernetics.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CYBERNETICS mean?
CYBERNETICS noun- The theory/science of communication and control in the animal and the machine.
- The art/study of governing, controlling automatic processes and communication.
- Technology related to computers and Internet.