Using my published work on another paper I am currently working on a new publication that uses the same control algorithms that I implemented on another experiment. The controllers are well explained in the published paper but I wish to incorporate the block diagrams and a summarized explanation of the controllers in the new paper. 

My question is: can I reuse these figures? do I require permission or a citation will suffice? My reasoning for doing this is to provide the reader with a clear picture of the controllers rather than just a reference to a paper.

thank you
You have two options. If what you want to do is exactly what you would do if the previous paper were by someone else, then just do that. Quote yourself as if you were another author and give appropriate references. 

However, if you wish to go beyond that and you have yielded copyright to the journal that published the first paper you need their permission - as stupid as that sounds. 

I expect that most reputable journals would give you permission (in writing, of course) since the work is yours. 

If you retain copyright though, you can copy it freely, but still reference the original. 

Well, a third option, is to just create a new diagram without reference to the old one, even if that also seems stupid. The simplest thing, though, may just be go send readers to the other paper for the diagram. 

Copyright law is a minefield. Self-plagiarism is a thing.