Sent my science vessel for expedition and got a message that, Found some ships during an expedition, but there is no one to control them.

I don't know how to control them, plz help me in this situation

Had same probleem, you need to send other ships with the science vessel, e.g. large cargo, fighter, recycler, battleships,  problem is that sometimes you lose them to black holes or pirates, so send what you can reasonable afford to lose if the worst happens typically I would send 1 science, 10 l cargo, 10 recycler, 1 fighter, 1 battleship    but its entirely up to you

Depending on what ships you find in an expedition, you have to have same type of ships in your fleet to control them. Sending just 1 science vessel in an expo, will just get you science vessels, but afaik you can't get those in an expo:(

From my experience...which admittedly was some time ago.. typically it takes 10 or more ships of the same type to "control" the shps that you find.  For example, i would send 25 battleships, 100 cruisers and 10 battlecruisers into expedition and sometimes find a few battleships, a couple of cruisers and a battlecruiser or 2.   Seems the more ships you send, the more you can control and bring home, but that's just an observation without any confirmation from the admin.  My 2 cents, anyway 

There are some online tools for oGame expos which may help... http://bontchev.my.contact.bg/ogame/expeditions.html